Immunoediting is crucial in cancer development and progression. This study compared the characteristics and prognosis of post-transplant breast cancer (PTBC) patients receiving immunosuppressants and general breast cancer patients.

Data from the Asan Medical Center Breast Cancer (AMCBC), kidney transplantation, and liver transplantation databases recorded during 1989-2013 were retrospectively analyzed. Four controls of AMCBC cohort per one case of PTBC cohort were selected based on tumor size, lymph node metastasis, and age.

After a median of 61 and 90.8 months after liver and kidney transplantation, respectively, 8 and 16 patients were diagnosed with breast cancer, respectively (p = 0.178). Mean age at breast cancer diagnosis was 51.9 (±8.7) and 45.2 (±4.5) years in liver and kidney transplantation patients, respectively. Age at diagnosis was significantly younger in kidney transplantation patients than in general breast cancer patients (45.2 ± 4.5 vs. 48.5 ± 10.1 years; p = 0.008). Cancer was detected via asymptomatic screening in 41.7% of the PTBC cohort but 30.6% of the control cohort (p = 0.241). In the PTBC cohort, 7 (29.2%) patients had stage 0 breast cancer compared with 1704 (9.7%) in the control cohort (p = 0.022); 22 (91.7%) patients had lymph node-negative cancer compared with 11,704 (66.8%) in the control cohort (p = 0.01). Estrogen receptor, progesterone receptor, and HER2 positivity did not differ between cohorts. Immunosuppressant use was not a poor prognostic factor for breast cancer patients.

Age at breast cancer diagnosis was younger in patients who received kidney transplants; the subtype and prognosis of breast cancer were comparable with that in the general cohort. Immunosuppressants do not adversely affect breast cancer prognosis.