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RTOG Phase III Trial Shows Radiation Therapy Lowers the Risk of Breast Cancer Recurrence for Women Diagnosed with "Good Risk" DCIS

June 4, 2012 | 

Initial results of the RTOG 9804, the first randomized, multi-center trial evaluating treatment with radiation therapy vs. observation) for women with "good risk" ductal carcinoma in situ (DCIS), will be presented at the American Society for Clinical Oncology 2012 Annual Meeting.

Philadelphia, PA (June 1, 2012) — Ductal carcinoma in situ (DCIS) — the earliest and most curable breast cancer — accounts for approximately 20% of all new diagnoses. Prior studies of participants with both low and high-grade DCIS showed that whole breast radiation helps prevent the recurrence of both invasive and non-invasive (in situ) breast cancer after lumpectomy. The RTOG 9804 trial sought to determine the benefits of radiation therapy (RT) versus patient observation alone in a population of women determined to have "good risk" disease (Tamoxifen was allowed, though not required, in both arms). The criteria for "good risk" disease included: no evident cancer symptoms prior to detection by a mammogram or other imaging test, only low or intermediate nuclear grade cancer as determined by pathology review, and cancers no larger than 2.5 cm, and at least 3 mm of tissue surrounding the lumpectomy site (the margins) determined to be cancer free by local instruction pathologists.

The study opened to accrual in December 1999 and closed in July 2006 having enrolled 636 of the planned 1790 study participants with 287 cases and 298 cases eligible for analysis in the radiation therapy and observation arms respectively. Two of the women receiving RT had a breast cancer recurrence compared with 15 women in the observation arm. "The research team hypothesized that we could successfully develop criteria that would identify a cohort of very low risk DCIS patients," says RTOG Principal Investigator Beryl McCormick, MD, Chief of External Beam Radiotherapy Service at Memorial Sloan-Kettering Cancer Center. "The low number of study participants who had a recurrence of their breast cancer strongly suggests we have developed criteria that identify good-risk DCIS patients, which is an important factor when evaluating treatment options for this patient population."

While the overall number of women experiencing a breast cancer recurrence was small, the addition of RT showed a statistically significant reduction in breast cancer recurrence, with 5-year rates of 0.4% and 3.2% for the RT and observation arms respectively. Women in the RT arm experienced more side effects than women in the observation arm with the increase in low-grade side effects being more pronounced. Grade 1 and 2 toxicities were 76% for the RT arm and 30% for the observation arm. RTOG will continue to follow the patients on this trial to assess long-term outcomes.

"This trial results can serve as one more piece of information for clinicians to consider in counseling patients with DCIS to determine if radiation is an appropriate option." says Julia White, MD, chair of the RTOG Breast Cancer Working Group and a Professor in the Department of Radiation Oncology at the Ohio State Comprehensive Cancer Center.

The results of RTOG 9804 will be presented at the 2012 American Society of Clinical Oncology on June 5, 2012 at 11 AM.

Authors:
B. McCormick1, K. Winter2, C. Hudis1, E. H. M. Kuerer3, E. Rakovitch4, B. L. Smith5, N. Sneige3, A. Shah6, I. Germain7, A. C. Hartford8, A. Rashtian9, E. M. Walker10, A. Yuen11, E. A. Storm3, J. L. Wilcox12, L. A. Vallow13, W. Small, Jr.14, A. T. Pu15, K. Kerlin16, J. White17

  1. Memorial Sloan-Kettering Cancer Center, New York, NY
  2. RTOG Statistical Center, Philadelphia, PA
  3. University of Texas MD Anderson Cancer Center, Houston, TX
  4. Toronto-Sunnybrook Regional Cancer Centre, Toronto, ON, Canada
  5. Massachusetts General Hospital, Boston, MA
  6. York Cancer Center, York, PA
  7. L Hotel-Dieu de Quebec, QC, Canada
  8. Dartmouth Hitchcock Medical Center, Lebanon, NH
  9. University of Southern California-Los Angeles, Los Angeles, CA
  10. Henry Ford Hospital, Detroit, MI
  11. Reading Hospital and Medical Center, Reading, PA
  12. Greenville SC CCOP, Greenville, SC
  13. Mayo Clinic, Jacksonville, FL
  14. Northwestern university Feinberg School of Medicine, Chicago, IL
  15. Radiological Associates of Sacramento, Sacramento, CA
  16. Southeast Cancer Control Consortium CCOP, Winston-Salem, NS
  17. Medical College of Wisconsin, Milwaukee, WI

The Radiation Therapy Oncology Group (RTOG) is administered by the American College of Radiology (ACR) and located in the ACR Center for Clinical Research in Philadelphia, PA. RTOG is a multi-institutional international clinical cooperative group funded primarily by National Cancer Institute grants CA21661, CA32115 and CA37422. RTOG has 40 years of experience in conducting clinical trials and is comprised of over 300 major research institutions in the United States, Canada and internationally. The group is currently accruing to 40 studies that involve radiation therapy alone or in conjunction with surgery and/or chemotherapeutic drugs or which investigate quality of life issues and their effects on the cancer patient. The American College of Radiology (ACR) is a national professional organization serving more than 32,000 radiologists, radiation oncologists, interventional radiologists and medical physicists with programs focusing on the practice of radiology and the delivery of comprehensive health care services.