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RTOG 9804: a prospective randomized trial for good-risk ductal carcinoma in situ comparing radiotherapy with
Beryl McCormick1, Kathryn Winter2, Clifford Hudis2
1Beryl McCormick and Clifford Hudis, Memorial Sloan-Kettering Cancer Center, New York, NY; Kathryn Winter and Jennifer Moughan, Radiation Therapy Oncology Group Statistical Center, Philadelphia; Amit Shah, York Cancer Center, York; Albert Yuen, Reading Hospital and Medical Center, Reading, PA; Henry Mark Kuerer, Nour Sneige, and Eric A. Strom, The University of Texas MD Anderson Cancer Center, Houston, TX; Barbara L. Smith, Massachusetts General Hospital, Boston, MA; Alan C. Hartford, Dartmouth Hitchcock Medical Center, Lebanon, NH; Afshin Rashtian, University of Southern California, Los Angeles, Los Angeles; Anthony T. Pu, Radiological Associates of Sacramento, Sacramento, CA; Eleanor M. Walker, Henry Ford Hospital, Detroit, MI; Jeannette L. Wilcox, Greenville SC Community Clinical Oncology Program (CCOP), Greenville, SC; Laura A. Vallow, Mayo Clinic, Jacksonville, FL; William Small Jr, Northwestern University Feinberg School of Medicine, Chicago, IL; Kevin Kerlin, Southeast Cancer Control Consortium CCOP, Winston-Salem, NC; Julia White, James Cancer Hospital, Ohio State University, Columbus, OH; Eileen Rakovitch, Toronto-Sunnybrook Regional Cancer Centre, Toronto, Ontario; and Isabelle Germain, L'Hotel-Dieu de Quebec, Quebec, Quebec, Canada. mccormib@mskcc.org.
Purpose:
The Radiation Therapy Oncology Group 9804 study identified good-risk patients with ductal carcinoma in situ (DCIS), a breast cancer diagnosis found frequently in mammographically detected cancers, to test the benefit of radiotherapy (RT) after breast-conserving surgery compared with observation.
Patients And Methods:
This prospective randomized trial (1998 to 2006) in women with mammographically detected low- or intermediate-grade DCIS, measuring less than 2.5 cm with margins ≥ 3 mm, compared RT with observation after surgery. The study was designed for 1,790 patients but was closed early because of lower than projected accrual. Six hundred thirty-six patients from the United States and Canada were entered; tamoxifen use (62%) was optional. Ipsilateral local failure (LF) was the primary end point; LF and contralateral failure were estimated using cumulative incidence, and overall and disease-free survival were estimated using the Kaplan-Meier method.
Results:
Median follow-up time was 7.17 years (range, 0.01 to 11.33 years). Two LFs occurred in the RT arm, and 19 occurred in the observation arm. At 7 years, the LF rate was 0.9% (95% CI, 0.0% to 2.2%) in the RT arm versus 6.7% (95% CI, 3.2% to 9.6%) in the observation arm (hazard ratio, 0.11; 95% CI, 0.03 to 0.47; P < .001). Grade 1 to 2 acute toxicities occurred in 30% and 76% of patients in the observation and RT arms, respectively; grade 3 or 4 toxicities occurred in 4.0% and 4.2% of patients, respectively. Late RT toxicity was grade 1 in 30%, grade 2 in 4.6%, and grade 3 in 0.7% of patients.
Conclusion:
In this good-risk subset of patients with DCIS, with a median follow-up of 7 years, the LF rate was low with observation but was decreased significantly with the addition of RT. Longer follow-up is planned because the timeline for LF in this setting seems protracted.
