A shorter course of radiation therapy given to breast cancer patients following mastectomy is safe and effective and cuts treatment time in half. That is according to data from a phase II clinical trial conducted by Rutgers Cancer Institute of New Jersey investigators and other colleagues who examined a hypofractionated regimen given over three weeks versus the traditional six week course of treatment.
When there is a concern that cancer cells may remain in the chest wall and lymph node regions following a mastectomy, a patient may be given targeted radiation over a five to six week period to further treat the breast cancer. "Receiving radiation for that long of a period becomes a quality of life issue for many patients. This includes the inconvenience of frequent travel to the treatment facility, as well as fatigue and other common side effects that can cause lost time at work and other challenges," notes the work's senior investigator Bruce G. Haffty, MD, professor and chair, Department of Radiation Oncology at Rutgers Cancer Institute, Rutgers Robert Wood Johnson Medical School and Rutgers New Jersey Medical School.
Researchers explored an accelerated course of radiation that cut treatment time in half. Currently, there is limited data supporting this type of treatment in this patient population.
From 2010 to 2014, 67 eligible patients with stage II to IIIa breast cancer were enrolled at Rutgers Cancer Institute of New Jersey and Huntsman Cancer Institute at the University of Utah. A dose of 36.63 Gy (a unit of radiation measurement) was given in 11 fractions of 3.33 Gy each. The fractions were delivered over a three-week period to the chest wall and area lymph nodes. The treatment also allowed for an optional four fractions (3.33 Gy each) of radiation to the chest wall at the mastectomy scar area, resulting in a total of 15 treatments over three weeks.
The aim was to not have any reported treatment toxicities of grade three or above. After a median follow up of 32 months, no grade three toxicities or higher were reported. There were 29 grade two toxicities reported, with a majority being skin rash followed by fatigue, similar to what may be experienced with the longer five to six week course of treatment. The estimated three-year survival rate of the cancer not coming back to the breast area was 89.2 percent. The estimated three-year survival rate for the cancer not coming back and spreading beyond the breast was 90.3 percent.
"While shorter courses of radiation therapy have been adopted in patients receiving radiation therapy to the breast alone after lumpectomy, there has not been adoption of shorter courses of treatment to the chest wall and lymph nodes after mastectomy. This trial demonstrated the safety of this shorter course approach in a prospective phase II study," notes Dr. Haffty.
Based on this study, a larger post-mastectomy randomized trial has been developed through the Alliance Cooperative Group with Haffty and current study investigators Matt Poppe of the Huntsman Cancer Institute and Atif J. Khan of Memorial Sloan Kettering Cancer Center leading the effort. In this phase III trial, a shorter course of radiation in the post-mastectomy, post-reconstruction setting will be compared to the more conventional five to six week course of treatment.