Thompson AM, et al. - Researchers performed a review to analyze patterns of care, recurrence and mortality among women with screen-detected ductal carcinoma in situ. After screen-detected ductal carcinoma in situ (DCIS), recurrent DCIS or invasive cancer was uncommon. A reduction in further events was evident in association with both RT and endocrine therapy. However, these therapies did not lead to reduced breast cancer mortality within 5 years of diagnosis.

Methods

• Researchers linked a prospective cohort of patients with DCIS diagnosed through the UK National Health Service Breast Screening Programme (April 1, 2003 to March 31, 2012) to national databases and case note review.
• Analysis of patterns of care, recurrence and mortality was performed

Results

• Researchers recognized 9,938 women with screen-detected DCIS; mean age was 60 years (range 46–87).
• Mastectomy (2,931) or breast conserving surgery (BCS) (7,007; 70%) was the treatment strategy.
• In this study, 697 (6.8%) patients showed further DCIS or invasive breast cancer after BCS (7.8%) or mastectomy (4.5%) at 64 months median follow-up (p < 0.001).
• Breast radiotherapy (RT) after BCS (4,363/7,007; 62.3%) resulted in a 3.1% absolute reduction in ipsilateral recurrent DCIS or invasive breast cancer (no RT: 7.2% vs RT: 4.1% [p < 0.001]) and a 1.9% absolute reduction for ipsilateral invasive breast recurrence (no RT: 3.8% vs RT: 1.9% [p < 0.001]); these reductions were irrespective of the excision margin width or size of DCIS.
• When the radial excision margin was < 2 mm, women without RT after BCS showed more ipsilateral breast recurrences (p < 0.001).
• Adjuvant endocrine therapy (1,208/9,938; 12%) was associated with a reduction in any ipsilateral recurrence, whether RT was received (hazard ratio [HR] 0.57; 95% confidence interval [CI] 0.41–0.80) or not (HR 0.68; 95% CI 0.51–0.91) after BCS.
• Women who developed invasive breast recurrence vs those with recurrent DCIS had a worse survival (p < 0.001).
• Only 46 of 321 deaths were attributed to invasive breast cancer.