Background: Adjuvant hormonal therapy (HT) reduces breast cancer recurrence risk in estrogen receptor-positive (ER+) ductal carcinoma in situ (DCIS). We assessed national practice patterns and influence of surgery and pathology on HT use in DCIS.
Methods: Data on DCIS patients diagnosed from 2004 to 2014 were extracted from the National Cancer Database, and patients were classified according to ER status and whether HT was received. Factors associated with HT use were assessed using Chi square tests for univariate analysis and logistic regression for multivariate analysis.
Results: Overall, 207,738 patients were evaluable as follows: ER+ (69.3%), ER- (13.7%), and ER unknown (17.0%). Among ER+ DCIS patients, 46.5% received HT, and HT use increased over time (42.3% in 2004 to 50.6% in 2014; p < 0.001). In contrast, 7.8% of ER- DCIS patients received HT, decreasing from 10.7% in 2004 to 5.9% in 2014 (p < 0.001). HT use varied by surgery type (BCS, 53.9%; unilateral mastectomy, 31.5%; and bilateral mastectomy, 8.1%; p < 0.001) and use was higher in BCS patients receiving adjuvant radiation than those not receiving radiation (62.7 vs. 29.1%; p < 0.001). Males treated with BCS were less likely to receive HT than females (43.2 vs. 54.0%; p < 0.001). In the BCS subset, higher use of HT was associated with more recent calendar year, age between 40 and 80 years, female sex, positive progesterone receptor status, and radiation use.
Conclusion: Adjuvant HT use in ER+ DCIS has increased over time, with the highest rates in patients treated with BCS and radiation. While inappropriate HT use was observed in ER- and bilateral mastectomy patients, the frequency of use in these categories decreased over time.