MIAMI BEACH – Adding radiotherapy and tamoxifen to breast-conserving surgery significantly reduces the local recurrence rate and the breast cancer–specific death rate in women with ductal carcinoma in situ, according to a systematic review and meta-analysis.
The review of 22 studies with a minimum of 10-year follow-up data showed that surgery plus radiation therapy nearly halved the rate of ipsilateral local recurrence from 23.5% with surgery alone to 13.5%, and the addition of tamoxifen cut the rate even further, to 9.2%.
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Dr. Kirsty Stuart
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The addition of tamoxifen to surgery and radiation also reduced breast cancer death rates from 3.1% without the drug to 1.5% with it, reported Dr. Kirsty Stuart of the Westmead Breast Cancer Institute at Westmead Hospital in Sydney, Australia.
"DCIS [ductal carcinoma in situ] treatment, however, will ultimately depend on the individual patient, their general condition, their tumor, and their fears," she told attendees at the annual meeting of the American Society for Radiation Oncology.
Dr. Stuart and colleagues conducted a meta-analysis of published randomized or nonrandomized trials of long-term outcomes in DCIS to determine the benefits of adjuvant radiotherapy and tamoxifen, a selective estrogen receptor modulator. The subjects all had pure DCIS with a minimum of 10-years’ follow-up, with data on treatment type and local recurrence. All studies were peer reviewed.
The investigators defined local recurrence as subsequent ipsilateral breast or chest wall disease (DCIS or invasive), and calculated the breast cancer death rate as the number of deaths from breast cancer divided by the total number of DCIS cases.
They identified a total of 22 qualifying studies dating from 1974 through 2011 with 6,167 patients. In all, 4.9% of patients had mastectomies, 51.8% had conservative surgery plus radiation, 41.2% had conservative surgery alone, and 2.1% had biopsy alone.
Among all cases, ipsilateral local recurrence was seen in 3.3% of mastectomy patients, 13.5% of patients who had surgery and radiation, 23.5% of surgery only patients, and 35.1% of biopsy only patients. Between-treatment comparisons showed that mastectomy was significantly better than each of the forms of therapy, both at preventing all cases of ipsilateral local recurrences and all cases of invasive local recurrence.
Looking at the addition of tamoxifen to surgery with or without radiation, the authors found that the drug significantly reduced the rate of local recurrence, from 24.1% with surgery alone to 19.8% with surgery and tamoxifen, and from 14.9% for the surgery/radiation combination to 9.2% for the two modalities plus tamoxifen.
Between-treatment comparisons showed that adding tamoxifen to radiation and surgery significantly improved recurrence rates over surgery plus radiation (P = .037), surgery plus tamoxifen (P = .0086), or surgery alone (P less than .000001). Compared with surgery only, the relative risk for invasive local recurrence was 0.71 for surgery plus tamoxifen, 0.63 for surgery plus radiotherapy, and 0.35 for all three treatments.
Invasive breast cancer death rates were also significantly lower when tamoxifen was added to surgery and radiation, decreasing from 8.4% without the drug to 4.3% with it.
"From the pooled data, conservative surgery alone for DCIS has a high recurrence rate that is partly reduced with tamoxifen," Dr. Stuart said.
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