Risk factors for non-invasive and invasive local recurrence in patients with ductal carcinoma in situ.

We aimed to identify clinicopathologic factors associated with local recurrence (LR) in a large population of DCIS patients treated with breast-conserving therapy between 1990-2001 in three health plans. Regression methods were used to estimate relative risks (RR) of LR. Among 2,995 patients, 325 had a LR [10.9 %; median follow-up 4.8 years (range 0.5-15.7)]. After adjusting for health plan and treatment, risk of LR was increased among women <45 years (RR = 2.1, 95 % CI 1.5-2.8), African-Americans (RR = 1.6; 95 % CI 1.1-2.1) and those with DCIS detected because of signs/symptoms (RR = 1.6; 95 % CI 1.2-2.0). After also adjusting for age and diagnosis year, pathologic features associated with increased LR were larger lesion size (RR = 2.9 for ≥20 low power fields of DCIS; 95 % CI 1.6-5.6) and involved (RR = 2.9; 95 % CI 1.6-5.2), or close margins (RR = 2.4; 95 % CI 1.6-3.8). Presentation with symptoms/signs was associated with increased risk of invasive recurrence; while African-American race, larger tumor size, and involved/close tumor margins were more strongly associated with increased risk of DCIS recurrence. Our findings suggest some risk factors differ for non-invasive and invasive LRs and that most factors are only moderately associated with increased LR risk. Future research efforts should focus on non-clinicopathologic factors to identify more powerful risk factors for LR.