Outcomes in patients with non‐invasive breast carcinoma

BACKGROUND AND AIM: Non‐invasive breast carcinoma is considered to be localized disease and is distinguished from invasive ductal and lobular carcinomas. The local recurrence of non‐invasive carcinoma after surgery may lead to development of invasive carcinoma and promote distant metastasis, which worsens the prognosis for breast cancer mortality. The distant metastasis of non‐invasive carcinoma may involve the ductal microvasculature without invasion. The outcomes of non‐invasive breast carcinoma were examined in this retrospective cohort study. METHODS AND RESULTS: Of 872 primary breast cancers diagnosed at a single center between May 2008 and March 2022, 93 (10.6%) were found to be non‐invasive carcinomas and were examined in this study. The breast cancer recurrence and survival rates of patients with non‐invasive carcinoma were analyzed retrospectively. The median follow‐up period was 1891 (range, 5–4804) days. All patients underwent surgical treatment [mastectomy with sentinel lymph node biopsy (SLNB) and partial mastectomy with or without SLNB, tumorectomy, and microdochectomy]. Postoperatively, radiation therapy was administered to 73 (78.4%) of the patients and endocrine therapy was administered to 64 (81.0%) of 79 patients with hormone‐receptor positivity. Of 26 patients who underwent partial mastectomy with SLNB, 24 (92.3%) showed isolated tumor cells in the SLNs on one‐step nucleic acid amplification. Local recurrence was observed in three (0.3%) patients; no distant metastasis was observed. One patient died of a noncancerous disease. The overall survival rate was 98.0% and the breast cancer‐specific survival rate was 100.0%. CONCLUSIONS: Non‐invasive breast carcinoma, like invasive breast carcinoma, causes local recurrence, but has a good prognosis without distant metastasis. The clinical significance of isolated tumor cells in the SLNs as a systemic component of non‐invasive breast carcinoma remains to be elucidated.