Background: Recent incidence, treatment patterns, and outcomes for node negative microscopically invasive breast cancer (MIBC) have not been reported.
Methods: State Health Registry of Iowa data identified women with ductal carcinoma in situ (DCIS), MIBC, and stage I breast cancer excluding MIBC (stage 1BC).
Results: From 2000 to 2013, 1,706, 193, and 4,514 women were diagnosed with DCIS, MIBC, and stage 1BC, respectively. MIBC increased at an annual percentage change of 2.1 (P = .041). MIBC was more frequently human epidermal growth factor receptor 2 positive than stage 1BC (39.7% vs 9.6%, P < .001). Mastectomy was performed more frequently in MIBC than DCIS (40.9% vs 30.6%, P = .014) or stage 1BC (40.9% vs 33.8%, P = .119). Chemotherapy was given to 4.1% of women with MIBC. Survival for women with MIBC was intermediate between DCIS and stage 1BC.
Conclusions: Management of MIBC is an increasingly frequent clinical scenario. Women with MIBC receive more aggressive local and systemic therapy than women with DCIS.
Keywords: Breast neoplasms; Cancer incidence; Mastectomy; Microinvasive tumor; SEER program.
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