Introduction
Historically, cancer patients were advised to “take it easy” while they underwent treatment and recovery. Now, there is overwhelming evidence that we should encourage our patients to do the opposite. By increasing physical fitness, patients can better tolerate cancer treatment, maximize their functional independence, improve survival, and increase their quality of life. Although there is no single exercise protocol or dose that has shown to be superior for breast and gynecological cancer patients as of yet, we can comfortably state that staying active in a variety of ways is vital for cancer treatment and recovery. A collaborative team-based approach is essential to the success of an exercise program for patients with breast and gynecological cancer. Typically, patients will received primary treatment from oncologists, radiation oncologists, and surgeons. Referral to a physiatrist, particularly one who specializes in cancer rehabilitation, can ensure a patient starts an appropriate and safe exercise program that takes into account their individual needs. Teaching, training, and supervision from experienced physical therapists, fitness trainers, and exercise physiologists specializing in cancer rehabilitation allow patients to safely increase their physical fitness and adherence to their exercise program. Family and friends are a vital support system for patients with breast cancer and should be involved in medical/surgical treatment, as well as rehabilitation efforts. This chapter will discuss the exercise recommendations and disease–specific modifications important for patients living with breast and gynecological cancers, highlighting the evidence of benefits and safety considerations. Compared to breast cancer, there is a significantly smaller body of literature exploring gynecological cancer and exercise, and therefore the majority of evidence presented in this chapter is derived from research examining breast cancer patients. When available, evidence pertaining to specific issues of patients with gynecological cancer will be presented.
Types of Exercise
Exercise regimens for breast cancer patients should include a variety of activities that cause different primary physiological effects: aerobic, anaerobic, muscle strengthening, bone strengthening, balance training, and flexibility training. Yoga, tai chi, and qigong comprise an exercise category that combines many of the previous categories while “emphasizing relaxation, meditation and spirituality.” The absolute and relative intensity of exercise is important to consider when prescribing an exercise regimen. The absolute intensity, commonly measured in metabolic equivalents, is the “rate of energy expenditure required to perform any physical activity” (see Table 3.1 ). Relative intensity can be measured objectively by VO 2max or the sing-talk test, or subjectively rated by the participant with a scale such as the rate of perceived exertion (see Table 3.2 ). The term physical activity generally refers to a wide range of occupational, recreational, and household activities, while exercise refers to dedicated time to endurance, strengthening, or sport activities. In this chapter the terms physical activity and exercise will be used interchangeably.
| METs (Approximate) | Activity |
|---|---|
| 1.0 | Sleeping, sitting quietly, meditating |
| 2.0 | Cooking, folding laundry, light gardening, playing musical instrument |
| 3.0 | Walking, child care (moderate), occupational standing tasks, Tai Chi |
| 4.0 | Bicycling (leisure), power yoga, raking leaves |
| 5.0 | Elliptical trainer, resistance training, dancing |
| 6.0 | Power lifting, rowing (vigorous), shoveling snow |
| 7.0 | Running (13 min/mi), racquetball, soccer (casual), backpacking |
| 8.0 | Running (12 min/mi), calisthenics, circuit training, rock climbing |
| 9.0 | Running (11.5 min/mi), stair treadmill, cross-country skiing (moderate) |
| 10.0 | Running (9 min/mi), soccer (competitive), swimming (vigorous) |
| 11.0 | Running (8.5 min/mi), stationary bike (vigorous), rope jumping (moderate) |
| 12.0 | Running (7 min/mi), rowing (competitive), bicycling (racing) |
| Numerical Rating | Qualitative Rating |
|---|---|
| 6 | |
| 7 | Very, very light |
| 8 | |
| 9 | Very light |
| 10 | |
| 11 | Fairly light |
| 12 | |
| 13 | Somewhat hard |
| 14 | |
| 15 | Hard |
| 16 | |
| 17 | Very hard |
| 18 | |
| 19 | Very, very hard |
| 20 |
Exercise Positively Influences Breast and Gynecological Cancer Prevention, Treatment, Survival and Recurrence
Exercise, in addition to being beneficial to general health, may prevent the development of breast cancer in a dose-dependent manner. The main proposed mechanisms of how exercise decreases the risk of developing breast cancer are via decreased adiposity, improvement of metabolic and hormonal abnormalities, and immunomodulation ( Fig. 3.1 ). Adiposity promotes a chronic inflammatory and hypoxic state, coupled with excessive hormone production, and should be viewed as a “preventable and reversible risk factor” for breast cancer. It is important to note that exercise has a greater impact on reducing obesity when combined with dietary modifications. Higher intensity exercise correlates with increased risk reduction up to a certain point, as exhaustive exercise can have detrimental effects on the muscular microenvironment. Current evidence is limited on whether the preventative effect of exercise is modified by age, race, or socioeconomic status, although some evidence points to a greater effect for postmenopausal women compared to premenopausal women. It is also unclear whether patients with a family history of breast cancer receive the same risk reduction benefit from exercise compared to those without genetic predisposition. There is strong evidence that increasing physical activity and limiting sedentary behavior lower the risk of endometrial cancer, with more limited evidence for ovarian cancer. It is important to note that there is a significant linear correlation between physical activity and melanoma risk, and therefore patients engaging in outdoor physical activity should be educated on sun-safe practices.
Treatment
The National Comprehensive Cancer Network (NCCN) and the American College of Sports Medicine (ACSM) recommend physical activity, including aerobic exercise and resistance training, for cancer patients undergoing active cancer treatment and posttreatment. Exercise can help patients better tolerate treatment, decrease treatment complications, and increase chemotherapy completion rates, translating to improved treatment outcomes. Exercise may have these effects by increasing perfusion and oxygenation of tumor cells by normalizing tumor blood vessels and by promoting immune cell mobilization and infiltration into tumors. Exercise may also work synergistically with chemotherapy to impact tumor growth. There is also evidence of a dose–response relationship between exercise frequency and intensity and chemotherapy completion rates. Patients need not limit activity before surgery, as there is strong evidence that the cardiopulmonary benefits of exercise help patients better tolerate anesthesia, with fewer complications postoperatively. Thus an individually structured exercise program consisting of aerobic and resistance training should be seen by clinicians and patients as an adjunctive breast cancer treatment.
Survival and Recurrence
The effect of physical activity on breast cancer survival and recurrence is an ongoing area of research. A metaanalysis by Ibrahim and Al-Homaidh observed an inverse relationship between physical activity and mortality in patients with breast cancer. Survivors who are overweight and obese are at higher risk for breast cancer recurrence, so it would seem that weight loss through exercise might be a feasible way to decrease that risk. A literature review by Loprinzi et al. found a nonsignificant risk reduction of breast cancer recurrence with increased physical activity. Thereafter, a robust systemic review and metaanalysis examining 123,574 patients by Lahart et al. concluded that an inverse relationship exists “between physical activity and all-cause, breast cancer-related death and breast cancer events.” In addition, the timing of activity may matter, with evidence suggesting that physical activity performed after cancer diagnosis confers greater mortality benefits compared to prediagnosis.
Exercise Guidelines
The 2018 Physical Activity Guidelines for Americans gives consideration to various categories of exercise and lays out minimum exercise goals for all Americans. Fig. 3.2 summarizes the goals for adults, as well as special considerations for older adults and those with comorbid conditions or disability. The evidence-based guidelines recommend goals and modifications so that all Americans, even and especially the elderly, disabled, and ill, can reap the benefits of increased physical activity. It is encouraged that physicians use this information to help patients create an individualized exercise program based on their fitness level and interests, to help them meet the minimum requirements. The guidelines emphasize minimizing total and interval duration of sedentary behavior, defined as “any waking behavior characterized by an energy expenditure ≤1.5 metabolic equivalents (METs), while in a sitting, reclining or lying posture,” and encourage increasing activity through daily tasks such as walking or cycling. Inactivity should be avoided, with patients returning to regular daily activities as soon as possible.
General Safety Considerations
Prior to starting an exercise regimen, patients should have a full history and physical by a physician to identify any safety considerations or contraindications to exercise. Relative and absolute contraindications to exercise can be found in Table 3.3 . If a patient does have a contraindication to exercise, they should be referred for immediate treatment and reevaluated after their condition has been treated and/or stabilized. Further testing may be necessary to assess patient tolerance and starting intensities for exercise. Pretesting for endurance exercise may include measuring VO 2max or the 6-minute walk test. Strength testing can be measured with one-repetition maximum testing and has been proven safe for patients with or at risk of lymphedema. Baseline testing should always be performed so that progress, failure to progress, or regression can be tracked. An individualized program should then be created based on the patient’s interests, exercise restrictions, and fitness level.
| Absolute Contraindications to Exercise | Relative Contraindications to Exercise |
|---|---|
| Platelet count <20,000 per µL a | Hemoglobin <6 g/dL |
| Fever a | Severe nausea vomiting or diarrhea b |
| New onset “unusual or unexplained severe tiredness or unusual weakness” | Cardiovascular impairment (e.g., coronary ischemia, heart failure) |
New-onset neurological deficits:
| Arrhythmia with symptoms of dyspnea, anxiety, or fatigue |
| Resting SBP >180 mmHg or DBP >110 mmHg | |
| Uncompensated heart failure, unstable angina | |
| COPD with superimposed pneumonia or exceptional involuntary loss of body weight (10% in the past half year of >5% in the past month) |
a Activity restricted to walking and activities of daily living.
b May be able to tolerate low intensity; maintain hydration; monitor body weight.
Overall, exercise prior to, during and after chemotherapy, radiation, and surgery has been shown to be safe and is recommended for breast cancer patients. Physicians may consider starting certain high-risk and/or deconditioned patients in a supervised program to ensure proper technique and improve adherence. Once the patient has completed active treatment and has shown competency with their exercise program, they may continue on their own with regular medical follow-up. A safe exercise “dose” for breast cancer patients and survivors has not been elucidated as of yet. However, there is robust evidence that aerobic and resistance training, either alone or in combination, are safe and feasible in this population. There is currently no upper limit on training for patients participating in a supervised, slowly progressive aerobic and resistance regimen. In an ideal world, patients would undergo a formal functional assessment prior to any surgical, radiation, or chemotherapeutic interventions to more accurately monitor declines in function and progress in therapy; this information would also help further research in this field.
The most common comorbid medical conditions that may affect the safety of an exercise routine for cancer patients and survivors are type II diabetes mellitus, coronary artery disease, heart failure, chronic obstructive pulmonary disease, obesity, hypertension, and osteoarthritis. Monitoring of blood glucose, heart rate, blood pressure, and oxygen saturation before, during, and after exercise may be warranted in patients who are frail, deconditioned, or have active medical issues. Modifications to an exercise protocol may be necessary due to complications and/or symptoms of these conditions, such as neuropathy, foot ulcers, dyspnea, edema, elevated blood pressure, and joint pain.
Barriers to Exercise/Adherence
Breast cancer patients encounter many barriers to participating in physical activity and exercise, so not surprisingly they tend to be more sedentary than the general population. Logistical barriers include time constraints due to frequent doctors’ visits and treatments, financial strain due to medical bills and inability to work, and lack of transportation and childcare. Physiological barriers include pain, fatigue, and neuropathy and will be further explored in subsequent sections of this chapter. Psychological barriers such as anxiety, depression, poor motivation, poor self-esteem, and cognitive deficits will also be discussed. Efforts to make physical activity more accessible and attainable for these patients are crucial, as emerging evidence continues to show that increased physical activity during cancer treatment results in better outcomes.
Support from physicians, therapists, other patients, family, and friends can help motivate patients to begin and continue an exercise program and stay physically active. Supervised and group exercises have consistently shown to increase exercise adherence in patients with nonmetastatic breast cancer. Patients with advanced disease tend to have more significant barriers to exercise and should be given alternatives such as home-based programs. Incorporating behavioral techniques such as goal setting and activity diaries may also be helpful. Making activities more fun, such as tailoring programs to patient’s interests, adding music, and avoiding monotony can also increase adherence.
With recent research supporting the role of technology in promoting physical activity, physical fitness, and weight loss, its potential to positively impact patients with cancer is now being explored. eHealth is defined as the use of information and communication technologies for health and can include the use of email, text messaging, push notifications, websites, and mobile-based applications; mHealth is the specific use of mobile-based applications to deliver eHealth. A mixed-methods study by Phillips et al explored breast cancer survivors’ preferences for mHealth physical activity interventions, finding that while survivors are interested in these interventions, their “preferences varied around themes of relevance, ease of use, and enhancing personal motivation.” Studies have shown improved physical functioning in cancer patients with the use of a smartphone app; however, it is unclear if results are superior to the use of a pedometer alone, a brochure, or other eHealth such as web- or email-based interventions. mHealth and eHealth for cancer survivors offer a promising new way to motivate and connect patients, but more research is needed to determine feasibility and effectiveness.
Medical and Surgical Complications of Breast Cancer: Exercise Benefits, Safety Considerations, and Barriers
Breast cancer treatment will generally include some combination of surgery, radiation, and chemotherapy, all of which can pose limitations to exercise and rehabilitation. In this section, we will review evidence-based safety considerations and benefits of various forms of exercise in relation to specific issues regarding surgical and medical treatments of breast cancer. Table 3.4 summarizes exercise modifications for specific complications of chemotherapy. Table 3.5 summarizes exercises that have been deemed safe and possibly beneficial for breast cancer-related complications.
| Complication | Modification |
|---|---|
| Leukopenia | Sanitize equipment, frequent hand washing |
| May prefer home exercises over group setting | |
| Thrombocytopenia | Low impact, low-intensity exercise |
| Avoid large increases in blood pressure | |
| Monitor for bleeding | |
| Anemia | Lower intensity of exercise |
| Fatigue | Avoid inactivity, avoid overtraining |
| Decrease intensity and duration | |
| Relaxation exercises | |
| Nausea/vomiting/diarrhea | Ensure adequate hydration |
| Avoid high-intensity exercise, rest when needed | |
| Dizziness | Decrease intensity and duration |
| Supervision to ensure safety | |
| Change positions slowly to avoid orthostasis | |
| Pain | May need to decrease intensity of aerobic and resistance exercises |
| Judicious use of analgesics | |
| Dyspnea | Adjust exercise intensity as needed |
| Monitor oxygen saturation | |
| Tachycardia/arrhythmia | Monitor heart rate before, during and after exercise |
| Reassurance if no other symptoms, can be due to chemotherapy | |
| Adjust training intensity as needed | |
| Monitor symptoms, discontinue exercise, and refer to physician if associated with dyspnea and anxiety or fatigue | |
| Numbness/neuropathy | Caution with free weights in upper extremities (increased risk to drop weights) |
| Supervision with balance exercises (increased risk of falls) | |
| Wear appropriate footwear with good grip | |
| Skin/nail changes | Protect skin and nails, may need to use soft gloves in severe cases |
| Avoid swimming and vigorous arm movement for patients with ports or catheters |
| Complication | Safe Exercises | Possibly Beneficial Exercises | Precautions/Modifications |
|---|---|---|---|
| Breast cancer-related lymphedema (BCRL) |
|
|
|
| Cancer-related fatigue (CRF) |
|
| Avoid overtraining |
| Bone loss/disease |
|
|
|
| Chemotherapy-induced peripheral neuropathy (CIPN) |
|
|
|
| Cognitive impairment |
| Yoga | May need supervision for safety awareness |
| Axillary web syndrome (AWS) | Flexibility | Flexibility | Avoid disuse of the limb |
Cancer-Related Fatigue
The NCCN defines cancer-related fatigue (CRF) as “a distressing, persistent, subjective sense of physical, emotional and/or cognitive tiredness or exhaustion related to cancer or cancer treatment that is not proportional to recent activity and interferes with usual functioning.” CRF is a prevalent issue among patients with cancer before, during, and after active treatment. Fatigue tends to worsen both with progression of cancer and with subsequent chemotherapy and radiation, affecting quality of life, mood, pain tolerance, cognition, and sleep. Patients suffering from CRF are more likely to be sedentary, accelerating deconditioning. While the exact pathophysiologic mechanism for CRF is unknown and is likely multifactorial, there is evidence that a concurrent, yet independent, parasympathetic underactivity and sympathetic overactivity contributes to the development and persistence of fatigue by inducing an inflammatory cascade, triggering production of proinflammatory cytokines. It is important to keep in mind that the cause of CRF is often multifactorial, and cancer patients may have other noncancer factors contributing to fatigue so an individualized approach to treatment is critical. Evaluation into and treatment of medical causes of fatigue such as anemia, psychological causes such as “catastrophizing” and depression, and sleep disorders are necessary. Overtraining and poor nutritional status can also contribute to fatigue and should be monitored on a regular basis.
Exercise alone, or combined with psychological interventions, is recommended as a first-line option for treating CRF. Many types of exercise have been shown to be safe and beneficial for slowing the progression of CRF, even in patients with advanced metastatic disease, including aerobic exercises, anaerobic exercises, and seated exercises. Supervised aerobic and resistance training, in comparison to self-administered regimens, appear more effective at improving CRF and quality of life. Patients who have completed primary treatment appear to benefit from a combination of exercise and psychological interventions, whereas patients receiving primary treatment can benefit from exercise alone.
It has been proposed, with some promising initial evidence, that mindful and relaxing exercises such as yoga may improve CRF by calming sympathetic overactivity and stimulating parasympathetic responses, thereby reducing inflammatory activity. Along similar reasoning, increasing physical activity in general and reducing body mass index (BMI) have been shown to reduce inflammation that may help improve fatigue Yoga has been proven safe for patients with CRF undergoing active treatment and posttreatment and is listed as a category 1 recommendation by the NCCN. Sprod et al. demonstrated safety, feasibility, and significant improvements in elderly, nonmetastatic cancer patients with CRF with a 4-week cancer-specific yoga intervention. Although any cancer type was eligible for the study, the majority were breast cancer survivors. Patients with greater adherence to a regular yoga practice of two to three sessions per week were more likely to report significant reductions of fatigue. Studies examining the effect of yoga on CRF used various types and styles of yoga; however, all were tailored specifically to reduce fatigue, and patients with functional limitations were given modifications and/or props as needed.
Altered Body Composition: Obesity and Cachexia
Breast cancer patients are at a higher risk of adiposity than the general population. This may be due to effects of breast cancer treatment, tendency toward more sedentary behavior, eating habits, hormone imbalances, metabolic changes, and menopausal status. Chemotherapy-induced amenorrhea causes menopause that increases the likelihood of weight gain. Chemotherapy regimens of cyclophosphamide, methotrexate, and fluorouracil cause an average weight gain of 2–6 kg. Additional risks for increased weight gain include premenopausal status, prolonged chemotherapy regimens, and receiving steroids.
There is now robust evidence that obesity and weight gain affect breast cancer development, progression, and recurrence via multiple biochemical pathways, including insulin resistance, chronic inflammation, endocrine fluctuations, and tissue hypoxia. In fact, obesity has been linked to as many as 15%–20% of cancer deaths. The link between excess weight gain and breast cancer development is stronger for postmenopausal women when compared to premenopausal women. Fortunately, adiposity is a reversible risk factor, and exercise has been shown to favorably affect breast cancer evolution in both pre- and postmenopausal women. Specifically, exercise has been shown to affect pathways that shift the body into an antiinflammatory, antimitotic and well-perfused state that is less likely to nurture the growth of a tumor. One of the most prominent risk factors for breast cancer recurrence is exposure to prolonged and elevated levels of estrogen. As adipose tissue is the main source of estrogens in postmenopausal women, reducing adipose tissue will invariably reduce estrogen exposure, thereby decreasing risk of breast cancer development. It is important to note that a combined program of exercise and dietary modifications was shown to reduce estrone and estradiol levels, as well as increase levels of sex hormone–binding globulin, more than an exercise program alone.
Patients who are overweight or obese can decrease adipose tissue and increase lean muscle mass with aerobic and resistance exercises, which may result in overall weight loss or maintenance of body weight. However, weight loss is not always a positive sign in breast cancer patients, as it may be due to muscle wasting, sarcopenia, and/or cachexia. Muscle wasting can occur due to the tumor itself, host responses, and effects of cancer treatments. Cancer cachexia is a distinct syndrome caused by inflammation and metabolic derangements that cannot be completely reversed by aggressive treatment of chemotherapy side effects and nutritional support. Sarcopenia is a separate entity that may present as a component of cachexia and is defined by low muscle mass and reduced gait speed. Patients with muscle wasting may not necessarily lose body weight, as loss of muscle mass is often coupled with increased fat mass, insulin resistance, and overall weight gain. Side effects of chemotherapy such as nausea, vomiting, diarrhea, and anorexia can also contribute to weight loss. Measurements of body weight alone may not give the full clinical picture, therefore monitoring of body composition parameters such as body fat and lean mass is recommended. Skeletal muscle wasting in cancer patients worsens prognosis, and endurance and resistance exercise have been shown to help maintain muscle mass and decrease inflammation in this population. Nutritional monitoring and support is essential for these patients while participating in an exercise program.
Bone Health
Bone Metastases
Bone is the most frequent site for metastatic disease in breast cancer, and while it carries a more favorable overall prognosis compared to visceral metastases, it can negatively affect functional capacity, fatigue, and quality of life. Clinicians and patients alike may be fearful of an increased risk for falls, fractures, and pain, although there have been multiple randomized controlled trials showing that individualized exercise programs that “avoid loading bones and minimize shear forces on areas of the body with metastatic lesions” are feasible, safe, and well tolerated in this population. According to the 2010 ACSM exercise guidelines for cancer survivors, patients with bone metastases should aim for the same minimum activity targets as cancer patients without metastases. Reaching these targets can prove especially challenging in this population, and the majority of patients with bone metastases do not meet the guidelines. Physiatrists, physical and occupational therapists trained in cancer rehabilitation can be a vital resource in developing a safe and effective program for these patients.
Palliative treatment of bone metastases, such as radiation and chemotherapy, can further impact physical functioning due to negative impacts on muscle strength, fatigue, and skin integrity. The Metastatic Exercise Training Trial examined the impact of a supervised exercise program for patients with metastatic disease. They determined that a moderate-intensity exercise program in this population is feasible; however, the study was limited by poor adherence, more-so in patients receiving chemotherapy. Clinicians should therefore be aware that patients undergoing chemotherapy may need additional modifications, often on a day-to-day basis based on symptoms, to improve adherence to exercise. Patients should also be monitored for new or worsening neurologic deficits, as bone metastases may cause nerve root or spinal cord compression requiring urgent neurosurgical evaluation. More studies are needed to elucidate if physical activity has an impact on treatment outcomes in this population. However, patients with metastatic disease are still encouraged to stay active to reap the cardiovascular and metabolic benefits of exercise. A few animal studies do show some promising evidence that weight-bearing exercises may in fact inhibit the spread of bony metastatic disease.
While the majority of patients with bone metastases will report bone pain, only bone pain associated with functional activity has been linked to an increased risk for pathologic fracture. Therefore it is recommended to encourage patients to start or continue an exercise regimen of aerobic and resistance exercises, unless they have or develop pain during activity. If pain develops, they should be assessed for pathologic fractures before returning to activity. Prompt referral to orthopedic surgery when there is a concern for an impending fracture is critical, as elective prophylactic fixation can avoid serious complications associated with acute pathologic fractures such as “extreme pain, urgent hospitalization, and the risk of emergency surgery with compromised outcome.” Postoperative exercise may need to be modified to accommodate weight-bearing restrictions. Fracture risk screening tools, such as Mirels’ Classification Scoring System and the World Health Organization screening tool (FRAX), may help clinicians identify patients that require exercise modifications. Clinicians and patients should be aware that one randomized controlled trial demonstrated bisphosphonates to be superior compared to exercise alone in preventing bone loss during breast cancer treatment. However, a subsequent study comparing a combination of guided paravertebral muscle resistance training, bisphosphonate, and radiation therapy to bisphosphonates and radiation therapy without resistance exercise showed significantly increased bone density in the area of stable spinal osteolytic metastases in the resistance exercise group, with no increased risk of fracture or disease progression.
Osteopenia/Osteoporosis
Osteopenia and osteoporosis in breast cancer patients can be caused by the cancer itself, as a separate disease process or a side effect of treatments such as chemotherapy, aromatase inhibitors, and steroids. Chemotherapy regimens, especially those including cyclophosphamide, methotrexate, and fluorouracil, can lead to bone loss by causing premature ovarian failure. The use of steroids alone significantly increases the risk for fractures. Tamoxifen, while preserving bone mineral density in postmenopausal women, can act as an estrogen antagonist in premenopausal women and actually increase bone loss. Severe decreases in bone mineral density may require dose reduction of drug therapy, potentially affecting survival. Research supports both aerobic and resistance exercises having beneficial effects on bone mineral density. It is recommended that all women with osteoporosis perform both impact and resistance exercises regularly to maintain bone integrity. Patients are encouraged to, at minimum, continue their current daily and functional activities to preserve bone mass, as bone loss occurs rapidly with unloading and is difficult to regain.
Cardiovascular Health
Breast cancer patients are at increased risk of cardiovascular dysfunction due to effects of chemotherapy, radiation, weight gain, and inactivity. Some of the most commonly used chemotherapeutic agents to treat breast cancer, Doxorubicin (DOX) and trastuzumab, cause dose-dependent cardiotoxicity, especially when given concurrently or sequentially. Cardiotoxicity is a common reason for dose reduction or discontinuation of chemotherapy, and there are currently no preventative treatments. Manifestation of cardiotoxicity from DOX and/or trastuzumab may be delayed for many years so it is important for clinicians and therapists to be aware of a patient’s treatment history in order to identify symptoms such as dyspnea, shortness of breath, and edema promptly. Animal studies show that exercise offers cardioprotection in animals receiving DOX; however, there are few studies examining animals given both DOX and trastuzumab. The REHAB trial showed initial evidence that aerobic exercise training can improve cardiopulmonary function in postmenopausal breast cancer survivors. Another trial by van Waart et al. showed that patients in a high-intensity exercise program better tolerate trastuzumab treatment, indicating a possible cardioprotective effect of exercise on trastuzumab cardiotoxicity.
Cytopenias
Cytopenias due to breast cancer treatment will be monitored and treated by the patient’s oncologist; however, it is important for patients, therapists, and trainers to be aware of safety precautions and exercise modifications in order to prevent injuries and adverse events. Patients with anemia should be monitored for symptoms such as dyspnea, fatigue, palpitations, and dizziness. Exercise intensity should be adjusted so that patients are symptom free. Severe anemia, defined as a hemoglobin less than 6 g/dL, is a relative contraindication to exercise and may require treatment with a blood transfusion prior to resuming activity. Patients with leukopenia are at increased risk for infection and should therefore follow strict hygiene precautions. Some may prefer to exercise at home so as not to expose themselves to contaminants at a public facility. Patients who receive granulocyte-colony-stimulating factor injections to prevent leukopenia may develop musculoskeletal and bone pain within 2 days after injection and may need intensity reduction or rest during this time. Lastly, thrombocytopenia puts patients at increased risk for bleeding. Patients should avoid high-impact, high-intensity exercise and be monitored for bruising or bleeding. A platelet count of <20,000/μL is a contraindication for exercise; however, patients may tolerate light walking and activities of daily living.
Chemotherapy-Related Neurotoxicity
Patients undergoing treatment for cancer may receive chemotherapeutic agents that cause significant neurotoxicity, both in the central and peripheral nervous systems. The most common neurotoxic chemotherapeutic agents used to treat breast cancer include cisplatin, carboplatin, paclitaxel, fluorouracil, and cyclophosphamide (see Table 3.6 ). Many neurotoxic effects of chemotherapy are seen in the immediate treatment period, are dose-dependent, and can resolve. However, with more patients participating in rehabilitation and exercise during treatment, it is important to be aware of them so that they can be identified and treated promptly. These symptoms can be debilitating and often require dose reduction and/or cessation of chemotherapy, potentially limiting the possibility for cure.
