Purpose: To determine the prognostic role of tamoxifen therapy for patients with ductal carcinoma in situ (DCIS) according to molecular subtypes. Methods: Data of 14,944 patients with DCIS were analyzed. Molecular subtypes were classified into four categories based on expression of estrogen receptor (ER)/progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2). Kaplan–Meier estimator was used for overall survival analysis while Cox proportional hazards model was used for univariate and multivariate analyses. Results: Luminal A subtype (ER/PR+, HER2−) showed higher (P = .009) survival rate than triple-negative (TN) subtype. Tamoxifen therapy group showed superior (P < .001) survival than no-tamoxifen therapy group. It had survival benefit only for luminal A subtype (P = .001). Tamoxifen therapy resulted in higher survival rate in subgroups with positive ER (P = .006), positive PR (P = .009), and negative HER2 (P < .001). In luminal A subtype, tamoxifen therapy showed lower hazard ratio (HR) compared to no-tamoxifen therapy (HR, 0.420; 95% CI 0.250–0.705; P = .001). Tamoxifen therapy was a significant independent factor by multivariate analysis (HR, 0.538; 95% CI 0.306–0.946; P = .031) as well as univariate analysis. Conclusion: Tamoxifen therapy group showed superior prognosis than the no-tamoxifen therapy group. Its prognostic influence was only effective for luminal A subtype. Patients with luminal A subtype showed higher survival rate than those with TN subtype. Active tamoxifen therapy is recommended for DCIS patients with luminal A subtype, and routine tests for ER, PR, and HER2 should be considered for DCIS.
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Acknowledgements This article was supported by the Korean Breast Cancer Society (WA35-20170205-01). Grant sponsor The research for this manuscript was not financially supported and none of the authors had any relevant financial relationships. We appreciate valuable discussion from the members of the Boramae hospital Breast cancer Study group (BBS).
All Science Journal Classification (ASJC) codes
- Cancer Research