Breast Cancer after Hodgkin's Lymphoma: An Observational Study

Background: Breast cancer (BC) counts for half of the excess risk of second cancer after Hodgkin Lymphoma (HL), but evidence about the clinical and pathological features of these cancers is lacking. The aim of this study was to evaluate whether these secondary BCs have distinctive characteristics compared to sporadic ones. Methods: This is a case-control study comparing patients who developed BC after receiving treatment for HL with an age-matched cohort of non-irradiated patients. All the cases were treated at the Veneto Institute of Oncology (Padua, Italy) between 2002 and 2017. We analyzed the clinical and pathologic features of BCs and compared treatment modalities using Chi-squared tests. Kaplan-Meier survival analyses were conducted to investigate overall and disease-free survival in the two groups. Results: In this study, 35 patients who were treated for HL and subsequently developed BCs were identified. BC occurred after a mean interval of 19.65 years (SD=10.08 years) from the HD diagnosis. According to the results, 4 of the patients treated for HL (11.4%) had a bilateral presentation. Also, 80% of the cases and 63% of the controls were ER+/HER- (p=0.516), while 20% of the HL group and 5.7% of the sporadic group were ER- /HER- (p=0.116). Ipsilateral BC recurrence (17.1% vs 8.6% in the sporadic BC group, p=0.346) and death events were more frequent in the HL group (11.4% vs 5.7% in the sporadic BC group, p=0.433), with a mean follow-up of 70 months (standard deviation=42.8months). Conclusion: Our data show that BC arising after HL often presented with bilateral localization, aggressive biological profiles, and had high recurrence rates. Dedicated treatment modalities should be considered and evaluated in a multidisciplinary setting.