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[[ce:hsp sp="0.25"/]]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[[ce:hsp sp="0.25"/]]+[[ce:hsp sp="0.25"/]]axillary (Ax)[[ce:hsp sp="0.25"/]]+[[ce:hsp sp="0.25"/]]sub-supraclavicular (SSCL) regions; with internal localization – all above[[ce:hsp sp="0.25"/]]+[[ce:hsp sp="0.25"/]]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[[ce:hsp sp="0.25"/]]+[[ce:hsp sp="0.25"/]]SSCL, 12 (10.9%) – Ax[[ce:hsp sp="0.25"/]]+[[ce:hsp sp="0.25"/]]IM, 13 (11.8%) – Ax[[ce:hsp sp="0.25"/]]+[[ce:hsp sp="0.25"/]]SSCL[[ce:hsp sp="0.25"/]]+[[ce:hsp sp="0.25"/]]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[[ce:hsp sp="0.25"/]]+[[ce:hsp sp="0.25"/]]IM, 13 (21%); Ax[[ce:hsp sp="0.25"/]]+[[ce:hsp sp="0.25"/]]SSCL, 15 (24.2%); Ax[[ce:hsp sp="0.25"/]]+[[ce:hsp sp="0.25"/]]IM[[ce:hsp sp="0.25"/]]+[[ce:hsp sp="0.25"/]]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.