Evolution of breast cancer management after mediastinal hodgkin lymphoma: Towards a breast- conserving approach.

Purpose: To analyse the clinical and histological characteristics of breast cancers (BC) occurring after Hodgkin lymphoma (HL), as well as their outcome with particular attention to the effectiveness and safety of breast-conservative surgery with radiation therapy (RT).

Materials and methods: This is a retrospective study of 218 patients who developed stage 0 to III BC after treatment for mediastinal HL between 1951 and 2022. Comprehensive demographic, clinical, and therapeutic data were collected for HL and BC, as well as survival and locoregional control. Statistical analyses were performed using R software version 4.1.1.

Results: The median age at HL diagnosis was 24 years [7-79]. BC appeared at a median age of 47 years [22-86], with a median interval of 21 years [5-51] after HL. Locoregional treatment included mastectomy in 117 (56.0 %) and lumpectomy in 92 (44.0 %), with postoperative RT in 99 patients (47.6 %). Isocentric lateral decubitus irradiation (ILD) was performed for 48 patients treated by tumorectomy (63.2 %). With a median follow-up of 29.7 years after HL and 7.7 years after BC, the 5-year overall survival (OS) and locoregional control rates were resp. 89.2 % and 86.4 % for invasive, and 100 % for in situ cancers. The 5-year metastasis-free survival rate was 87.4 % [95 % CI: 82.7-92.4 %]. No late sequelae was reported.

Conclusion: Breast-conserving surgery, combined with appropriate RT, can be considered in the treatment of BC after HL despite prior thoracic irradiation. This approach provides comparable outcomes in terms of local control and survival while reducing the risk of long-term complications associated with mastectomy.