Abstract
BACKGROUND: Age is a known risk factor for recurrence in women with ductal carcinoma in situ (DCIS) treated with breast-conserving surgery (BCS). We explored the relationship between age, other risk factors, and recurrence. METHODS: Using a prospectively maintained database of DCIS patients undergoing BCS from 1978 to 2010, the association of age and recurrence risk was analyzed using Kaplan-Meier estimates, multivariable analysis, and competing risk multivariable analysis. RESULTS: Overall, 2996 cases were identified. Median follow-up for those without recurrence was 75 months; 732 were followed for ≥10 years, and 363 (12 %) had recurrence [192 (53 %) DCIS, 160 (44 %) invasive, 11 (3 %) unknown]. Risk of recurrence decreased with age, even after adjustment for eight clinicopathologic variables on multivariable analysis [hazard ratios (HR), with <40 years of age as the reference: 40-49 years, 0.82 (p = 0.36), 50-59 years, 0.46 (p = 0.0005), 60-69 years, 0.50 (p = 0.003), 70-79 years, 0.56 (p = 0.02), ≥80 years, 0.21 (p = 0.0015)]. This association persisted for cohorts with and without radiation therapy. Using competing risk multivariable analysis, the effect of age on invasive recurrence was empirically stronger than for DCIS recurrence. Ten-year invasive recurrence was 16 and 6.5 % in women <40 years of age and women ≥40 years of age, respectively. Only 0.6 % of the population ultimately developed distant disease; those <40 years of age constituted 4.7 % (141/2996) of the population, but 21 % (4/19) of those developed distant disease. CONCLUSIONS: The risk of recurrence of DCIS decreases with age. This effect is particularly strong at the extremes of age and is independent of other clinicopathologic factors. The oldest women are at low risk of recurrence, while the youngest women have a higher overall, and especially invasive, recurrence rate, although mortality remains low. These findings should be incorporated into risk/benefit discussions of treatment options.