Impact of a prior diagnosis of DCIS on survival from invasive breast cancer.

A diagnosis of invasive breast cancer after DCIS can be described as a new primary cancer or as a local invasive recurrence. It is of interest to determine if, among women with early-stage breast cancer, a past history of DCIS influences survival. We retrieved the records of 306,249 women diagnosed with stage I or stage II breast cancer between 2004 and 2012, in the surveillance, epidemiology, and end results registries database, of whom 5395 had a previous diagnosis of DCIS. For each patient, we extracted information on the year of diagnosis, age at diagnosis, tumor size, nodal status, grade, estrogen receptor status, type of surgery (lumpectomy/mastectomy), use of radiotherapy (no/yes), prior DCIS (no/yes), cause of death, and follow-up time. For each case with prior DCIS, we recorded information on the year of diagnosis of DCIS, laterality of DCIS, and treatments received for DCIS. We matched 3979 patients with a prior DCIS to 3979 patients without a prior DCIS, according to the various prognostic features of the invasive cancer. We estimated the risk of death from breast cancer for patients with invasive ductal carcinoma, with and without a prior diagnosis of DCIS. We identified 306,249 women with stage I/II breast cancer, of whom 2335 had a prior ipsilateral DCIS and 3060 had a prior contralateral DCIS. Breast cancer-specific survival at 9 years was 94.6 % for patients with a prior DCIS (ipsilateral or contralateral) and was 95.2 % for patients with no prior DCIS (p = 0.32). In a matched analysis (3979 matched pairs), the hazard ratio for death from breast cancer for patients with a prior ipsilateral DCIS, compared to patients with no prior DCIS, was 0.91 (95 % CI = 0.49-1.68; p = 0.75). A prior diagnosis of ipsilateral DCIS does not impact upon the prognosis of women with early-stage invasive breast cancer. This suggests that primary breast cancers and local invasive recurrences following DCIS are similar conditions and should be treated in the same way.