Locoregional Management and Prognostic Factors in Breast Cancer Patients with Ipsilateral Internal Mammary and Axillary Lymph Node Involvement
Menée auprès de 117 patientes atteintes d'un cancer du sein non métastatique traité sur la période 2014-2019 et présentant une atteinte ganglionnaire (durée médiane de suivi : 3,82 ans ; âge médian au diagnostic : 46 ans), cette étude analyse les résultats d'un traitement multimodal (chimiothérapie néoadjuvante, résection, radiothérapie adjuvante) et met en évidence les facteurs pronostiques associés
Purpose: Breast cancer patients with ipislateral axillary and internal mammary (IM) lymph node involvement (cN3b) often forego IM node resection. Therefore, radiation is important for curative therapy. However, prognosis is not well-described in the era of modern systemic therapy and limited data exist to guide optimal locoregional treatment recommendations. Methods:We retrospectively reviewed 117 patients with non-metastatic cN3b breast cancer treated at our institution between 2014-2019. Staging included ultrasound evaluation of all regional nodal basins. All patients received neoadjuvant chemotherapy (NAC), resection of the breast primary and axillary nodal dissection, followed by adjuvant radiation to the breast/chest wall and regional nodes. Institutional guidelines recommend a 10 Gy boost to radiographically resolved nodes, and 16 Gy boost to unresolved nodes. Overall survival (OS), recurrence (RFS), locoregional (LRRFS), internal mammary (IMRFS), and distant metastasis free survival (DMFS) were evaluated with Kaplan Meier analysis. A multivariable model for RFS was constructed. Results: Median follow-up for 117 patients was 3.82 years. Median age at diagnosis was 46 years and 56 (48%) patients were receptor group ER+/HER2-. Mastectomy was performed in 96 (82%) of patients, 38 (32%) had biopsy confirmed IMC involvement, and 8 (7%) had IM node dissection. The median initial radiation dose was 50 Gy (range, 50-55) and IMC boost 10 Gy (range, 0-16). The 5-year OS, IMRFS, LRRFS, DMFS, and RFS were 74%, 98%, 89%, 68% and 67% respectively. On multivariable analysis, a clinical complete response (CR) of the IM nodes or pathologic ypN0 status had improved 5-year RFS with HR 0.24 (p=0.006) and HR 0.27 (p=0.05), respectively. Extranodal extension or lymphovascular invasion were associated with worse 5-year RFS with HR 4.13 (p=0.001) and HR 2.25 (p=0.04), respectively. Conclusion: Multimodality therapy provides excellent locoregional control of 89% at 5 years for cN3b breast cancer patients. Adjuvant radiation yields a 5-year IMRFS of 98%. Clinical and pathologic response of IM nodes are independently prognostic for RFS.
International Journal of Radiation Oncology, Biology, Physics 2022