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Ductal carcinoma in situ is associated with good long-term disease- specific survival, but tumors that recur as invasive disease—particularly after radiotherapy—increase risk of death.
In a retrospective study, more than 50,000 women with DCIS were treated with total mastectomy or breast-conserving surgery (lumpectomy) plus radiation between 1988 and 2003. Both treatments yielded similar 10-year disease-specific survival rates, Dr. Mohammed Nazir Ibrahim of Sligo General Hospital, Ireland, said.
The investigators analyzed a Surveillance, Epidemiology, and End Results (SEER) dataset that included 8,285 in situ tumors; 33% of patients had total mastectomies and 30% had lumpectomy with radiotherapy. Nearly all the remaining patients had lumpectomy only; 2.4% did not undergo surgery or radiotherapy, and 0.3% had radiotherapy only. The analysis also revealed that the diagnosis of carcinoma in situ is increasing in the United States at a rate of 0.5% annually, Dr. Ibrahim said.
Important prognostic factors included grade 4 tumors, which had a hazard ratio (HR) of 1.7 compared with grade 1. African Americans had a more than twofold risk of death compared with Caucasians (HR 2.1). Hormone receptor-negative status, conferred a twofold increase in risk of death (HR 2.2).
In another study, Dr. Irene Wapnir of the Stanford (Calif.) Comprehensive Cancer Center presented long-term outcomes after invasive breast tumor recurrence in women with primary DCIS, from National Surgical Adjuvant Breast and Bowel Project trials B-17 and B-24. Between 1985 and 1994, 2,612 women were randomized to lumpectomy alone, lumpectomy plus whole-breast irradiation, or lumpectomy plus whole-breast irradiation with or without tamoxifen. The median follow-up was more than 12 years.
Breast cancer-specific survival ranged from 96% to 98%; patients receiving lumpectomy, radiation, and tamoxifen had the best survival. Of 336 deaths, 83 were from breast cancer. Among 242 cases of invasive breast tumor recurrence, there were 35 deaths, 22 of which were breast cancer-related. Nine deaths occurred in lumpectomy-alone patients (HR 1.17), 21 in lumpectomy plus radiation patients (HR 3.04), and 5 in lumpectomy plus radiation plus tamoxifen patients (HR 1.91).
Ibrahim M.N. et al. Comparison of survival rates in carcinoma in situ of the breast treated with total mastectomy to breast-conserving surgery and radiotherapy. Abstract 519.
Wapnir I. et al. Long-term outcomes after invasive breast tumor recurrence (IBTR) in women with DCIS in NSABP B-17 and B-24. Abstract 520.
Commentary |
As these two studies confirm, outcome after DCIS is excellent with current standard therapy. Invasive disease following DCIS is associated with the highest risk of subsequent mortality, but that risk is very low. Mastectomy does not appear to offer benefit over lumpectomy and radiation. Attention to surgical margins has reduced the risk of both in situ and invasive local recurrence. Now we need to develop risk models that can help us understand an individual patient's subsequent risk of ipsilateral as well as contralateral invasive cancer. Some women may benefit from adjuvant tamoxifen (for estrogen receptor- positive DCIS) and/or more aggressive surgery. With this in mind, practitioners would be able to make apt treatment recommendations for the growing population of women with DCIS. Given that the majority by far will survive DCIS, it is important to provide appropriate treatment and to avoid overtreatment. — Hope S. Rugo, M.D.
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