Mode of Detection of Second Breast Cancers in Patients Undergoing Surveillance After Treatment of Ductal Carcinoma in Situ.

Abstract

For patients undergoing posttreatment surveillance after ductal carcinoma in situ (DCIS), the NCCN Guidelines for Breast Cancer recommend annual breast imaging and physical examination every 6 to 12 months for 5 years, and then annually. The aim of our study was to evaluate the modes of detection (imaging, patient reported, or physical examination) of second cancers in a cohort of patients undergoing surveillance after primary DCIS treatment to better inform surveillance recommendations. We performed a retrospective cohort study of patients with DCIS treated between January 1, 2008, and December 31, 2011, within a large integrated health care system. Information on patient demographics, index DCIS treatment, tumor characteristics, and mode of detection of second breast cancer was obtained from the electronic health record or chart review. Our study cohort consisted of 1,550 women, with a median age of 59 years at diagnosis. Surgical treatment of DCIS included lumpectomy (75.0%; n=1,162), unilateral mastectomy (21.1%; n=327), or bilateral mastectomy (3.9%; n=61), with or without sentinel lymph node biopsy. Additionally, 44.4% (n=688) and 28.3% (n=438) received radiation and endocrine therapies, respectively. Median follow-up was 10 years, during which 179 (11.5%) women were diagnosed with a second breast cancer. Of the second cancers, 43.0% (n=77) were ipsilateral and 54.8% (n=98) contralateral, and 2.2% (n=4) presented with distant metastases; 61.5% (n=110) were invasive, 36.3% (n=65) were DCIS, and 2.2% (n=4) were Paget's disease. Second breast cancers were imaging-detected in 74.3% (n=133) of cases, patient-detected in 20.1% (n=36), physician-detected in 2.2% (n=4), and detected incidentally on imaging or pathology from procedures unrelated to oncologic care in 3.4% (n=6). In our cohort of patients undergoing surveillance following diagnosis and treatment of DCIS, 2% of second breast cancers were detected by a clinical breast examination. This suggests that survivorship care should prioritize mammography and patient education regarding breast self-examination and symptoms that warrant evaluation to detect second breast cancers.