SPECT-CT localization of axillary sentinel lymph nodes for radiotherapy of early breast cancer

Sergey Novikov; Pavel Krzhivitskii; Sergey Kanaev; Petr Krivorotko; Nikolay Ilin; Julia Melnik; Nadejda Popova

doi:10.1016/j.rpor.2019.10.003

SPECT-CT localization of axillary sentinel lymph nodes for radiotherapy of early breast cancer

Rep Pract Oncol Radiother. 2019 Nov-Dec;24(6):688-694. doi: 10.1016/j.rpor.2019.10.003. Epub 2019 Nov 8.

Authors

Sergey Novikov¹, Pavel Krzhivitskii¹, Sergey Kanaev¹, Petr Krivorotko², Nikolay Ilin¹, Julia Melnik¹, Nadejda Popova¹

Affiliations

¹ Department of Radiotherapy and Nuclear Medicine, N.N. Petrov Institute Oncology, St Petersburg, Russia.
² Surgery department, N.N. Petrov Institute Oncology, 197758, St Petersburg, Russia.

Abstract

Purpose: To evaluate the opportunities of single photon emission tomography/computerized tomography (SPECT-CT) for localization of axillary sentinel lymph nodes (ASLNs) and subsequent radiotherapy planning in women with early breast cancer.

Material and methods: Individual topography of ASLN was determined in 151 women with clinical T1-2N0M0 breast cancer. SPECT-CT visualization of ASLNs was initiated 120 min after intra-peritumoral injection of 99mTc-radiocolloids. Doses absorbed by virtual ASLNs after the whole breast irradiation with standard and extended tangential fields were calculated on a treatment planning station.

Results: SPECT-CT demonstrated a large variability of ASLN localization. They were detected in the central subgroup in 94 (61%) patients, in pectoral - in 77 (51%), and in interpectoral - in 4 (3%) patients. Sentinel lymph nodes "lying on the chest" were revealed in 35 (23%) cases.We found that with standard tangential fields coverage of ASLNs was obtained only in 20% of evaluated women. Extended tangential fields can effectively irradiate ASLNs localized in all axillary sub-regions with the exception of ASLNs "lying on the chest".

Conclusion: SPECT-CT mapping of ASLNs in women with cT1-2N0M0 breast cancer reveals their variable localization. This information can be important for planning of radiation treatment in women that underwent breast conserving surgery without an axillary surgery.

Keywords: Breast cancer; Imaging; Radiotherapy; Sentinel lymph nodes.