Fig. 6.1
A mammogram demonstrating a non-palpable cluster of microcalcifications in the outer quadrant of the breast (a) and a second mammogram demonstrating the position of the wire located adjacent to the clip left in place after the vacuum-assisted biopsy (b). Microcalcifications (b) non-palpable node
6.2.1 Indications
Despite some key disadvantages of the procedure such as the presence of a foreign body at pathological assessment, the possible wire transaction or migration, the patient discomfort especially if the procedure is done the day before the operation, and the interference with the surgical approach [18], WGL has had a considerable spread over the years, becoming the standard of care in several institutions although overall uptake has been slow.
It is indicated in the presence of non-palpable breast lesions or clusters of microcalcifications or parenchymal distortion. This method could be also applied in the case of multicentric and multifocal lesions [19], in case of diffuse microcalcifications or in presence of retroareolar lesions.
6.2.2 Description of the Surgical Procedure
Once the non-palpable breast lesion is localized with the hooked wire, in order to facilitate incision placement, images should be sent to the operative room with wire entry site indicated on them. The localization wire has the potential to migrate at many stages prior to and during surgery when the patient changes position or when traction is applied by the surgeon. In addition, in cases of small lesions, precise localization of the target lesion may be difficult due to the thickness of the tip of the wire. Besides, there have been reports of wire transection occurring during the time of surgery.
Placement of incision is limited by the way the wire is inserted and may have an impact on the cosmetic outcome (Fig. 6.2). Therefore, the incision should be placed as directly as possible over the mass to minimize tunneling through breast tissue, but it should be noted that the insertion site of the wire on the skin may be remote from the ideal surgical incision in many cases, resulting in an undesirable incision and more extensive dissection to locate the lesion and wire tip [20]. With superficial lesions, the wire entry site is usually close to the lesion and thus may be included in the incision. With some deeper lesions, the wire entry site is on the shortest path to the lesion and so may still be included in the incision. Once the incision is made, a block of tissue is excised around and along the wire in such a way as to include the lesion. This process is easier and involves less excision of tissue if the localizing wire has a thickened segment several centimeters in length that is placed adjacent to or within the lesion. The wire itself can then be followed into breast tissue until the thick segment is reached, at which point the excision can be extended away from the wire to include the lesion in a fairly small tissue fragment. With many lesions, the wire entry site is in a fairly peripheral location relative to the position of the lesion, which means that including the wire entry site in the incision would result in excessive tunneling within breast tissue. In such cases, the incision is placed over the expected position of the lesion, the dissection is extended into breast tissue to identify the wire a few centimeters away from the lesion itself, and the free end of the wire is pulled up into the incision. A generous block of tissue is then excised around the wire. Intraoperative ultrasonography may be useful for identifying the tip of the needle and facilitating excision, particularly in the case of a deep lesion or biopsy site in a large breast.
Fig. 6.2
Placement of incision is limited by the way the wire is inserted
At the end of the surgical procedure, a radiography should be performed intraoperatively on all wire-localized biopsy specimens to confirm the proper excision of the lesion (Fig. 6.3). If the lesion is missed, another tissue sample may be excised if the surgeon has some idea of the likely location of the missed lesion. In case of diffuse microcalcifications, if some of them are close to one margin at radiography, the surgeon has the possibility to remove more glands on that side in order to avoid positive excision margins with DCIS in mural edge. If, however, the surgeon suspects that the wire was dislodged before or during the procedure, then the incision should be closed, and repeat localization and biopsy should be performed later.
Fig. 6.3
A radiograph of the surgical specimen. The margins of the excised specimen were marked with surgical stitches (a) in order to better orient the X-ray (b). It shows the presence of the entire lesion in the middle of the excised tissue
6.3 ROLL Technique
In 1998, Luini and colleagues at the European Institute of Oncology in Milan [21] pioneered a new technique of localizing non-palpable breast lesions, and then it has been refined according to different modalities. This method derives its advantage from the accuracy in locating non-palpable lesions through an intralesional injection of a small amount of high-molecular-weight radioactive tracer, consisting of human serum albumin aggregates conjugated with technetium-99m. It is injected more frequently under ultrasound guidance (Fig. 6.4) but also by stereotactic guide, depending on whether nodes are ultrasonographically visible or microcalcifications are present at mammography or clips are left in place after mammotome biopsy. The size of albumin colloid is 100–150 μm in diameter in order to prevent migration of the radioactive tracer through the lymphatic path, ensuring its permanence in the area of inoculum. The dose involves the injection of 99mTc-labelled colloid in 0.1 cm3 followed by 0.1 cm3 of air and by 1 cm3 of iodinated water-soluble contrast if the injection is performed under stereotactic guide. The use of a proper probe for the detection of gamma radiations in the form of digital (strokes per second—sps) or acoustic signal enables the intraoperative localization of the inoculated and its precise surgical resection. ROLL requires localization to be performed within 24 h of surgery due to the 6 h half-life of 99mTc-labelled colloid [22], giving flexibility in the scheduling of the procedure and minimizing the discomfort of the patients.
Fig. 6.4
The performance of the intratumoral injection of the radioactive tracer under ultrasound guidance
6.3.1 Indications
In recent years, the ROLL has had an increasing application, so that it is, in many qualified centers, the technical of choice for surgical removal of non-palpable lesions of the breast.
The ROLL is currently indicated in the presence of non-palpable breast lesions detected by ultrasound or mammographic examination, such as clusters of microcalcifications, small opacities with spiculated or irregular margins, parenchymal distortion, and radial scars. This method is not however applied in the case of multicentric and multifocal lesions, in case of diffuse microcalcifications, or in presence of retroareolar lesions for possible radioactive contamination of the ducts.
6.3.2 Description of the Surgical Procedure
ROLL is a composite multidisciplinary procedure based on several connected steps and therefore there are many specialized skills involved in the procedure. First of all, the inoculation of the 99mTc-labelled colloid is performed by nuclear medicine in collaboration with the radiologist inside the lesion or in the area corresponding to the microcalcifications or near the clip. Then, a breast scintigram in anterior-posterior and lateral projections performed after the injection is mandatory to verify the proper and punctiform centering of the lesion with reference to the nipple, the inframammary fold, and the axilla. Moreover, any possible spills with skin contamination must be highlighted as well as any possible intraductal or intravascular spread that could make difficult or impossible the identification and then the excision of the centered lesion [18].
The equipment used in the operative room for the excision of the breast lesion involves the application of a radioactivity detector—handheld gamma probe—in the form of a metal cylinder containing inside a scintillator crystal capable of detecting gamma radiations emitted by 99m-Tc previously inoculated and transforming them into an electrical signal. The probe is connected by wire or by Bluetooth to an external digital reader that allows to convert the detected radioactivity both into a digital signal (sps) readable on a display and into an acoustic signal with an intensity and frequency proportional to the radioactivity captured over the investigated area [21].
In the operating room, even before preparation of the surgical field, the probe can be passed slowly by the surgeon over the surface of the breast in a perpendicular fashion; this maneuver allows to locate the orthogonal projection of the lesion itself on the skin and the surgeon can highlight it with a skin-marker pencil. In this way, the surgeon can choose the more appropriate surgical incision according to the position of the lesion (Fig. 6.5). In fact, depending on the location and the lesion characteristics (size, suspicion of malignancy), and the size and shape of the breast, skin incisions can be performed radial or arched. Radial incisions are generally preferred in case of intraductal calcifications, highly suspicious lesions, and lesions located in the lower quadrants of the breast, while arched incisions are mostly preferred for lesions located in the upper quadrants because they provide a better cosmetic result. Incisions around the nipple, with an excellent aesthetic result, are preferred, if possible, for all benign lesions.
Fig. 6.5
Intraoperative use of the handheld gamma probe, inserted in a sterile sheath, in order to confirm the presence of radioactive peak counts on the skin to determine the appropriate incision
Once the incision has been performed, the probe, inserted in a sterile sheath, allows to identify the area with higher signal intensity, thus indicating the direction in which surgical resection should be performed. Moving the probe slowly, the surgeon can verify that the higher acoustic signal intensity is always at the center of the specimen being excised, maintaining a look on the surgical field constantly. Therefore, the surgeon is able to precisely identify the area with the highest intensity of the acoustic signal and guide the surgical resection around it (Fig. 6.6). When the excision is completed, the probe can immediately verify the absence of residual signal on the surgical field, proving that the lesion was completely removed; if there is residual radioactivity, the surgeons have the possibility to enlarge the margins of resection.
Fig. 6.6
The surgeon used the gamma probe to confirm that the radioactive hotspot was centrally located within the excision specimen (a) and, once the specimen was excised, the surgeon used the gamma probe to ensure that maximal radioactivity with a rapid fall in gamma signal intensity was confined within the specimen (b)
An X-ray of the surgical specimen must always be performed in order to confirm the actual presence of the non-palpable lesion or the clip or the cluster microcalcifications in the excised piece and to assess the extent of surgical resection margins and the possibility of proceeding to enlarge the resection. Moreover, the specimen should be oriented, defining the surgical margins with clips or stitches in order to make the pathologist’s task easier.
6.4 Alternative Methods of Localization
6.4.1 Radioactive-Seed Localization
In contrast to ROLL, radioactive seed localization (RSL) involves percutaneous injection of a small titanium seed (with a size of 4 mm by 0.8 mm) radiolabelled with 125-I into the non-palpable lesion under either stereotactic or ultrasound guidance via a standard 18-gauge needle. At surgery, the gamma probe is guided to the focal hotspot on the skin directly overlying the lesion. Once an incision is made at this location, the gamma probe is used to detect the distance from the dissection plane to the seed and to ensure that the excised specimen contains the radioactive hotspot; intraoperative radiography can also be used to provide further visible confirmation. In RSL, however, because a radiolabelled titanium seed is used for localization (instead of radiocolloid), a separate injection of radiocolloid that can migrate to the axillary nodes is necessary for the performance of sentinel lymph node biopsy.
Several advantages and limitations are associated with RSL technique. ROLL needs to be performed within 24 h before surgery because of the short (6 h) half-life of the radiolabelled colloid (99mTc), whereas RSL is generally performed within 5 days before surgery [23, 24] because the half-life of 125-I is 60 days [25, 26]. This flexibility in the timing of seed insertion in RSL provides a clear advantage of this technique over ROLL by reducing the time pressure on the radiology department and operating theaters, thereby enabling better resource management on the day of surgery [27]. Concern over migration and subsequent loss of inserted seeds has been raised in RSL procedures, but clinically relevant seed migration is rare and has been reported in less than 1% of patients [28].
6.4.2 Ultrasound-Guided Surgery
Ultrasonographic imaging has been used for interventional purposes to acquire histological diagnosis using core biopsies and also for preoperative placement of wires for non-palpable lesion localization [26, 29]. With advancements in ultrasonography technology, by reducing the size of scanners, enhancing their portability, and improving imaging quality, and with the increased use of ultrasonography by breast surgeons, patients with lesions that are visible on ultrasonographic images can now undergo excision guided by intraoperative ultrasound (IOUS) without the need of preoperative localization [30]. Despite the aforementioned data, current evidence on IOUS has limitations owing to the lack of data from large RCTs comparing IOUS to the standard WGL in the published meta-analyses. Although no significant difference was found in the distribution of in situ disease between treatment groups, only one small RCT [31] comprising 49 patients (26 in the IOUS group versus 23 in WGL group) was included in the meta-analysis [29], and the remaining cohort-controlled studies had differences in potential confounding factors between groups. Therefore, the risk of selection bias toward less defined in situ malignancy being excluded from the IOUS group and the WGL group was not identified [29]. The lack of data from RCTs of non-palpable breast cancer, combined with a lack of long-term oncological outcomes from large series, is prohibitive in gaining insightful conclusions about the efficacy of IOUS in this disease. Another major limitation to the widespread implementation of IOUS has been the ability of surgeons to acquire formal training and accreditation in breast ultrasonography. The successful application of IOUS is dependent on expertise in the technique and experience in the use of ultrasonography during tumor excision.
6.5 Discussion
Widespread use of diagnostic breast imaging and screening programs has revolutionarily changed the diagnosis of breast cancer: this has directly resulted in a substantial increase in the number of diagnosed breast cancers which are clinically non-palpable, and, accordingly, the technology to deal with these lesions has developed commensurately.
However, as DCIS is being detected as radiographic lesions only, the need for image-guided localization of non-palpable breast lesions prior to surgical excision emerged, and identifying the presence and extent of a carcinoma in situ component is more difficult using standard clinical or radiological techniques than in isolated invasive disease. Primary breast-conserving surgery may therefore result in incomplete excision of cancer or inadequate clearance margins, which both typically require women to have reoperation to the breast. In a recent retrospective study among women who have undergone breast-conserving surgery in England, the authors found that the reoperation rates differed between women with and without carcinoma in situ. In particular one in five women who had breast-conserving surgery had a reoperation, but reoperation was nearly twice as likely when the tumor had a carcinoma in situ component associated [32].
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