Breast papilloma without atypia and risk of breast carcinoma

The incidence of asymptomatic papilloma has increased with the rising popularity of core needle biopsy for breast lesions. In this study, the risk of benign papilloma without atypia for subsequent breast carcinoma during follow-up was evaluated. From January 2000 to December 2010, among 39,461 women with breast ultrasonography, 37,847 women with benign papilloma on biopsy or excision, with benign diseases on biopsy, and with only ultrasonography performed were recruited. Women with concurrent or prior high-risk lesions (atypia, phyllodes tumor, or lobular neoplasm) or malignancies, or with a follow-up period of less than 12 months were excluded. The eligible 12,302 women were classified into three groups; papilloma (n = 265, patients with benign papilloma without atypia at excision), benign (n = 3,066, patients with benign results other than high risk results on core needle biopsy), and ultrasonography (n = 8,971, patients who underwent ultrasonography only without biopsy or surgery). The relative risks (RRs) of the papilloma and benign groups were calculated with intervals of 2 years using the Poisson regression analysis with age, family history, follow-up period, and breast parenchymal density being adjusted, and the ultrasonography group was used as a reference. The RR of the papilloma group was 4.8 (95% confidence interval [CI], 2.5-9.0), significantly higher than 1.5 (95% CI, 1.0-2.1) of the benign group. In the first 2 years, the RR of the papilloma group was 5.2 (95% CI, 2.2-12.6) but it dropped to 2.2 (95% CI, 0.5-9.2) during the next 2 years. Afterward, the RR increased over time although statistical significance was not achieved. Benign papilloma without atypia increased breast cancer risk fivefold when the ultrasonography group was used as a reference, higher than other benign lesions.