Characteristics associated with recurrence among women with ductal carcinoma in situ treated by lumpectomy

that may predict risks of recurrence in women with ductal carcinoma in situ (DCIS) have not been consistently identi-fied. We identified factors associated with recurrence as DCIS versus invasive breast cancer and determined the 5-year absolute risks of recurrence as a function of these factors. Methods: We conducted a population-based cohort study among 1036 women in the San Francisco Bay Area who were aged 40 years or older when diagnosed with DCIS and treated by lumpectomy alone from January 1983 through December 1994. Standardized pathology reviews were conducted to determine disease recurrence, defined as DCIS or invasive breast cancer diagnosed in the ipsilateral breast containing the initial DCIS lesion or at a distant site more than 6 months after the initial diagnosis and treatment of DCIS. Conditional logistic regression models were used to determine factors associated with recurrence. All statistical significance tests were two-sided. Results: During a median follow-up of 77.9 months, 209 women (20.2%) experienced a recurrence. Overall, the 5-year risks of recurrence as inva-sive cancer and as DCIS were 8.2 % (95 % confidence interval [CI] 6.6 % to 9.8%) and 11.7 % (95 % CI 9.9 % to 13.3%), respectively. The 5-year risks of recurrence as invasive can-cer and as DCIS were 4.8 % (95 % CI 3.7 % to 6.8%) and 4.8 % (95 % CI 3.8 % to 5.8%), respectively, for women with low-nuclear-grade DCIS; 11.8 % (95 % CI 9.9 % to 14.1%) and 17.1 % (95 % CI 15.5 % to 18.7%), respectively, for women with high-nuclear-grade DCIS; 11.6 % (95 % C