Preoperative CTLG provides important information about the status of SLNs in patients with early-stage breast cancer. The relations among tumors, lymph-vessels, and SLNs can be assessed together with the surrounding anatomy. Guided by CTLG imaging findings, SLNB can easily be performed as a minimally invasive procedure. SLNB for breast carcinoma was introduced in the mid-1990s, and has already been performed on thousands of patients with breast carcinoma. Nevertheless, many unanswered questions remain (Schwartz et al., 2002). One of the problems to be solved is the lack of methods for identifying the full set of SLNs draining the primary tumor. As one possible solution to this problem, lymphangiography using an oil-in-water emulsion of contrast medium has been employed to assess the stages of malignancies. However, several complications have hampered widespread adoption of this method (Sato et al., 2007; Tangoku et al., 2004). Another possibility is CTLG, which allows visualization of the anatomy and provides functional data about lymphatic flow after interstitial injection of commercially available and commonly used intravenous contrast agents designed to enhance CT images. This method is simple, inexpensive and safe, such that CTLG has been performed in various fields, including video-assisted breast surgery (Yamashita and Shimizu, 2008), as well as in breast cancer patients requiring neoadjuvant chemotherapy (Ue et al., 2007) and patients with gastrointestinal malignancies (Tangoku et al., 2007). CTLG is technically easy to perform and the data acquisition time is short (Ue et al., 2007). In addition, CTLG can be performed at any institution equipped with a multi-detector row CT scanner.
In women, breast surgery is often performed using a lateral skin incision on the lateral mammary fold. This lateral skin incision saves the integrity of the skin blood supply, allows for a complete breast gland removal, and has benefits in terms of body image for women as no scars are apparent in the frontal view. Axillary clearance and/or SLNB can be easily performed via such a lateral skin incision (Regolo et al., 2008). On the other hand, the standard treatment for localized breast cancer in men is a modified radical or simple mastectomy including resection of the nipple since up to a third of men with breast cancer have stage III disease due to the small amount of breast tissue (Fentiman et al., 2006). For advanced male breast cancer, axillary dissection is usually performed via the same incision. However, in clinically node-negative cases, SLNB will probably become standard practice in the future. Another incision will thus be needed for SLNB in most cases. CTLG allows the detection of the sites of the SLNs preoperatively. Thus, the axillary region incision site can easily be determined, thereby shortening the operation.
CTLG will make SLNB in men with early-stage N0 breast cancer more practical, because CTLG has already become a standard method for women in many medical centers. Frequently, breast cancer is diagnosed in men at an advanced stage, making SLNB inappropriate, but a considerable proportion of patients still present with a clinically negative axilla, thereby making them candidates for a less invasive method of axillary staging (Gentilini et al., 2007). In addition, although the data were limited, a panel of the American Society of Clinical Oncology stated that SLNB would be unlikely to be any less accurate in men than in women, and that treatment of male breast cancer has paralleled that of female breast cancer (Lyman et al., 2005). The safety and usefulness of SLNB have also been reported for male patients. Thus far several papers have described SLNB in men, documenting detection rates of 100% and no false negatives in patients who received a back-up axillary clearance (Gentilini et al., 2007; Boughey et al., 2006; Cimmino et al., 2004; De Cicco et al., 2004; Flynn et al., 2008; Goyal et al., 2004; Kitada et al., 2011; Koukouras et al., 2012; Rusby et al., 2006). These findings support the reliability and reproducibility of SLNB as a technique applicable to male breast cancer patients.
In the American College of Surgeons Oncology Group Z0011 randomized trial, axillary lymph node dissection did not significantly affect overall or disease-free survival of patients with clinical T1-T2 breast cancer and a positive SLN who were treated with lumpectomy, adjuvant systemic therapy, and tangential-field whole-breast radiation therapy (Giuliano et al., 2011). More effective systemic therapy would presumably influence excellent local and distant outcomes, even if the regional nodes obtained by SLNB harbored metastases associated with a higher risk for systemic disease. A relatively large series of men with breast carcinoma suggested that men benefit from adjuvant systemic therapy for breast carcinoma, with the greatest benefit being that adjuvant hormonal therapy (Giordano et al., 2005; Ribeiro and Swindell, 1992). In our two cases, adjuvant endocrine therapy using tamoxifen was performed, and the second patient also received neoadjuvant endocrine therapy due to work-related issues. In men, CTLG has the potential to enhance the usefulness SLNB by reducing the complications associated with axillary lymph node dissection and improving quality of life with no reduction in survival duration.
In conclusion, CTLG allowed accurate SLN localization by providing rapid and adequate visualization of the direct connection between the SLN and its afferent lymphatic vessels. Detailed cross-sectional images of lymphatic anatomy during CT resulted in successful SLNB based on clear detection of the incision site. CTLG is especially valuable for identifying lymphatic drainage and the locations of SLNs in male breast cancer.