Comparison of two treatment strategies for irradiation of regional lymph nodes in patients with breast cancer: Lymph flow guided portals versus standard radiation fields.

ABSTRACT

AIM AND BACKGROUND: Radiotherapy being an essential part of breast cancer treatment, we evaluate various radiotherapy strategies in patients with breast cancer. MATERIALS AND METHODS: Lymph node (LN) scintigraphy was performed in 172 primary patients with BC. LN visualization started 30-360 min after intratumoral injection of 75-150 MBq of 99mTc-nanocolloids. Our standard recommendation for postoperative radiotherapy in patients with LN invasion by BC were as follows for patients with external localization of tumour - breast + axillary (Ax) + sub-supraclavicular (SSCL) regions; with internal localization - all above + internal mammary nodes (IM). Proposed strategy of lymph flow guided radiotherapy is based on the assumption that only regions that contain 'hot' LNs must be included in a treatment volume. RESULTS: Among 110 patients with external localization of BC, Ax LNs were visualized in all cases and in 62 patients it was the only region with 'hot' LN. Twenty-three patients (20.9%) had drainage to Ax + SSCL, 12 (10.9%) - Ax + IM, 13 (11.8%) - Ax + SSCL + IM regions. After the visualization of lymph flow patterns, standard treatment volume was changed in 87/110 cases (79.1%) in 56.4%, reduced, in 22.7%, enlarged or changed. In 62 patients with tumours in internal quadrants, we revealed the following patterns of lymph-flow only to the Ax region in 23 (37.1%); Ax + IM, 13 (21%); Ax + SSCL, 15 (24.2%); Ax + IM + ISSCL, 11 (17.7%) cases. After lymph-flow visualization, the standard irradiation volume was reduced in 53/62 (85.5%) cases. CONCLUSION: Visualization of an individual lymph flow pattern from BC can be used for the optimization of standard fields used for irradiation of regional LNs.