Introduction
Pain and decreased function in breast cancer are common and can be significant. One large study showed that 47% of women treated for breast cancer experienced pain and 58% reported sensory disturbances into the third year postoperatively, half rated this pain as moderate to severe. Pain severe enough to limit function occurs in about 60% of cases. As just one example of functional loss, consider arm morbidity after breast surgery and adjuvant treatments. As one might imagine, limitations in upper extremity range of motion have been linked to a reduction in ability to perform activities of daily living as well as a reduced health-related quality of life. As such, pain and disability are among the most feared complications of breast cancer treatments.
Postmastectomy Pain Syndrome
Persistent breast pain following surgery is referred to as postmastectomy pain syndrome (PMPS). It is a collection of symptoms following any breast surgery, not just mastectomy, and can include lumpectomy, breast reconstruction, augmentation or reduction, and importantly is also inclusive of procedures done in the upper outer quadrant of the breast and axilla as well. Though there are no universally accepted diagnostic criteria, it is agreed that pain must persist for more than 3 months postoperatively after all other causes of pain have been excluded. It typically presents with pain of neuropathic and/or musculoskeletal symptoms. Pain is commonly localized to the breast, chest wall, axilla, or ipsilateral shoulder or arm. This results in secondary limitations in functional range of motion and strength, including grip strength. Risk factors for development of this type of pain are multifactorial and are presented in Table 14.1 .
| Demographics |
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| Treatment and complication related |
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| Psychosocial risk factors |
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The evaluation of pain in this patient population requires an understanding of the pathophysiology and characteristics of breast cancer as a foundation. From there the patient-specific evaluation of the malignancy along with other comorbidities is used to clarify the cause(s) of the pain. Some pertinent questions are outlined in Table 14.2 .
| Severity | “How severe is your pain?” |
| Character | “How would you describe your pain?” |
| Location | “Where is your pain located? Can you point to it with one finger or is it diffuse?” |
| Radiation | “Does your pain travel or shoot anywhere?” |
| Timing | “When do you feel the pain the worst?” |
| Ameliorating/exacerbating factors | “What makes your pain better/worse?” |
| Impact | “How does this pain affect your daily life?” |
A careful history and physical examination will then focus on identifying pain generators. These can be divided into tumor- and treatment-related pain syndromes and then further divided into nociceptive and neuropathic pain syndromes. See Fig. 14.1 for common causes of pain in this population.
There are a few elements that require special attention during the physical exam of this unique population. For example, an inspection of the skin over irradiated areas and along the surgical incision should be done to evaluate for any signs of wound infection, adhesions, seromas, and neuromas. This should include the skin of the axilla for those who underwent nodal irradiation or lymphadenectomy. The muscles of the anterior and posterior chest wall should be palpated for asymmetry or myofascial pain. Observe for scapular winging. The shoulder should be moved through the full range of motion and inspected for any restrictions or weakness. Provocative maneuvers can be used to rule out rotator cuff or other musculoskeletal injuries to the shoulder girdle.
Radiation Fibrosis Syndrome
Under the umbrella of PMPS are several other syndromes that are seen in the breast cancer population that the clinician should be aware of. The first is radiation fibrosis syndrome, a collection of neuromuscular, musculoskeletal, and other complications resulting from radiation treatments. Nearly all patients will have some symptoms in the acute period of radiation treatment. However, it is the late-term effects of radiation that manifest after years, even decades, that define this condition. Radiation fibrosis is a chronic, progressive, unpredictable, and nonreversible condition resulting from continued fibrotic changes to the radiated tissues. These tissues can be of any type—bone, muscle, skin, ligaments, viscera, or nerves. The proposed mechanism is a positive feedback loop resulting in proliferation of fibrin, into the microvasculature, which ultimately ends with progressive sclerosis of all tissues in the radiation field. Often times, symptoms will manifest when either neurovascular compromise and/or atrophy ultimately develop. Sclerotic ligaments and tendons may shorten, resulting in loss of tissue elasticity and range of motion. Radiated musculature surrounding the shoulder, such as the rotator cuff, can become atrophied and lead to loss of function. Radiated chest wall musculature can begin to go into painful spasms, a result of ectopic firing of the injured motor nerves. This is seen particularly in the pectoralis major, serratus anterior, latissimus dorsi, and intercostal muscles. The thoracodorsal, long thoracic, medial, and lateral pectoral nerves may also be in the radiation field and can lead to functional impairments.
Management of radiation fibrosis is largely symptomatic. Physical and occupational therapy can use manual techniques to mobilize fibrotic tissue. Stretching of the tissues causing shoulder dysfunction can improve range of motion and prevent further morbidity. There is some evidence that nerve stabilizers for neuropathic pain and opioid analgesics for nociceptive pain can be effective. Botulinum toxin injections into painful spastic muscles, including those used for breast reconstruction, can also provide relief. Though there is no known way to reverse radiation fibrosis, there is some evidence that its progress can be slowed using the combination of tocopherol and pentoxifylline. Tocopherol has vitamin E activity and is thought to be a free radical scavenger. Pentoxifylline limits fibroblast collagen proliferation and platelet aggregation among other properties. In combination, they serve to reduce oxidative stress and subcutaneous fibrosis. The optimal dose and duration has not been well defined, and there is evidence that high-dose tocopherol can increase all-cause mortality. In general, total dose vitamin E around 700–1000 IU/day and pentoxifylline 800 mg/day is recommended, with the author dividing it into twice-daily dosing. This combination is the only known treatment that could potentially slow the progression of radiation fibrosis.
Postreconstruction Pain
Another aspect of PMPS is the cluster of painful conditions seen in those undergoing breast reconstruction. Breast reconstruction is generally done to restore body image and sexuality following breast cancer treatments. However, it has been shown at 1 year postoperatively that those undergoing reconstruction have more pain versus those that did not. Those with implant-based reconstruction had more pain than those without implants, with the highest cohort being those that had submuscular implants, particularly those involving augmentation.
Breast reconstruction generally requires a muscular “pocket” or myocutaneous flap to hold the implant in place and to prevent erosion through the skin. Traditionally, implants have been placed behind the pectoralis major muscle (subpectoral). The muscle is dissected from the chest wall and a tissue expander is placed beneath it. See Fig. 14.2 (from Ref. ). The expander is slowly filled with saline over weeks to months to stretch the muscle and fascia to the desired size. The patient is then taken back to operating room, and the expander is replaced with the implant. This stretching of the pectoralis and chest wall tissues is associated with significant discomfort in the expansion phase. This pain can result in inadequate expansion as well as removal of the expanders, abandoning reconstruction.
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