Fran Lowry

April 07, 2016

HOLLYWOOD, Florida — Hypofractionation, a shorter course of radiation delivered for 3 weeks instead of 5 weeks, is now preferred over whole-breast radiation, according to the 2016 National Comprehensive Cancer Network (NCCN) updated guidelines for breast cancer.

"For breast conserving surgery and radiation, the big take-home point is that shorter courses of radiation, or hypofractionation, are preferred for whole-breast radiation," Kilian E. Salerno, MD, director of breast radiation and soft tissue/melanoma radiation at Roswell Park Cancer Institute, Buffalo, New York, told Medscape Medical News.

"The rationale for using that word 'preferred' is from a preponderance of very good data that outcomes with hypofractionation are at lease equivalent. Women can have a shorter course of radiation, typically about 3 weeks of treatment as opposed to the 5 weeks of treatment done previously, and still have the same control rates, if not better, the same cosmetic outcomes, if not better, and the same, if not better, side effect profile," Dr Salerno said here at the National Comprehensive Cancer Network (NCCN) 21st Annual Conference.

Dr Kilian Salerno

Conventional fractionation delivers 1.8 to 2 Gy per fraction to a total dose of 45 to 50 Gy given over 5 weeks.

Hypofractionation is given over a shorter course, utilizing larger doses per fraction, with >2 Gy per fraction to lower total dose. These doses can include 40 to 42.5 Gy given in daily fractions for whole-breast or 34 to 38.5 Gy given in twice-daily fractions for partial breast irradiation, given over an accelerated time frame (3 weeks).

Hypofractionation's newly preferred status is based on long-term results from large studies from Canada (Whelan et al, N Engl J Med. 2010;363:513-520) and the UK START study (Haviland et al, Lancet Oncol. 2013;14:1086-1094) as well as others, Dr Salerno commented.

As previously reported by Medscape Medical News, there is mounting evidence supporting hypofraction in breast cancer. Two recent US studies provide further evidence of less toxicity and a better quality of life with hypofraction compared with conventional fractionation.

Dr Salerno told delegates at the NNCN annual meeting: "The regimen we use is 40 Gy in 15 fractions for 3 weeks, according to the results of the START B trial, which is the UK study. The NCCN panel felt very strongly that if you get the same results with less side effects, the shorter course is better," she said.

Another Important Option ― Omit Radiation

Another important issue discussed in the 2016 NCCN guidelines is the option to omit radiation in some women with breast cancer, Dr Salerno said.

"We know that not all women need to have radiation, and we are trying to determine who has a low risk of recurrence and in whom we can omit radiation. It is an active decision not to give it," she said.

"The guidelines reflect women 70 years of age or older with small, node-negative, ER-positive breast cancers who would go on to receive endocrine therapy. We know that the recurrence risks are quite low," Dr Salerno said.

Dr Salerno cited data from the PRIME II study (Fyles et al, N Engl J Med. 2004;351:963-970), which looked at women aged 65 years and older, and also from the CALGB 9343 study (Hughes et al, J Clin Oncol. 2013;31:2382-2387) and the NSABP B-21 study (Kunkler et al, Lancet Oncol. 2015), both of which included women aged 70 years or older with small cancers, negative nodes, and negative margins, and who were ER/PR positive. The results from all three of these studies showed no survival detriment to forgoing radiation in this population, she noted.

"There are a lot of studies being done now that are going beyond using age as the sole criterion and are looking at features of tumor biology and then moving towards better ways of stratifying recurrence risk. I think those trials are going to be very informative and take us beyond what we are currently using," Dr Salerno said.

Regional Nodal Irridation for Some?

The 2016 NCCN breast cancer guidelines also address the issue of which patients need regional nodal irradiation, and to what extent, she said.

"Several studies are showing a benefit with regional nodal radiation for recurrence and disease-free survival but not for overall survival, so we know there's a benefit to radiation," Dr Salerno said.

"We are working to best determine who does or does not need that treatment. I don't want people to take home that this is a blanket statement for every single patient to be treated, but you have to strongly consider this treatment based on data we now have, particularly from the EBCTCG meta-analysis [Early Breast Cancer Trialists Collaborative Group, Lancet. 2014;383:2127-2135] in patients who are one to three nodes positive," she said.

The 2016 NCCN breast cancer guidelines have also updated and refined the guidance regarding regional nodal irradiation, Dr Salerno said.

"The areas to be treated in regional nodal irradiation include the supraclavicular nodes, the infraclavicular nodes, the axillary bed at risk, and the internal mammary lymph nodes. These are the nodal areas that were included in the aforementioned studies," she said.

"When treating the internal mammary nodes, especially on the left side, the radiation oncologist needs to think about heart and lung dose," Dr Salerno said.

"We are trying very hard with our modern techniques to target what needs to be treated fully and minimize treating the remainder of the patient that does not need to be treated, in particular, heart and lung. We can tailor our therapies to help mitigate the side effects of treatment," she said.

Dr Salerno added that the newer trend of the NCCN guidelines is to refine its language regarding recommendations for management of disease instead of making large changes. She said that it was nice to hear another expert talk about 'tweeks and refinements' to the guidelines as opposed to the dramatic rearrangements seen in past years, and increasingly, this is going to be the way going forward, she predicted.

Approached for comment, William J. Gradishar, MD, Betsy Bramsen Professor of Breast Oncology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, told Medscape Medical News that the updated guidelines for the management of breast cancer bring greater clarity to the options that patients now have.

Dr William Gradishar

"The updates include shorter durations of radiation therapy, which is now considered a first choice for many patients. Additionally, the role of accelerated partial breast irradiation and the circumstances where radiation can be avoided were discussed. A large part of Dr Salerno's discussion also focused on the clinical scenarios in which regional node basins should be irradiated and her review of the data that support those recommendations in early-stage breast cancer," he said.

The NCCN guidelines are also striving to help clinicians personalize their management of breast cancer patients, noted Tuya Pal, MD, from Moffitt Cancer Center, Tampa, Florida.

Dr Tuya Pal

"As new data become available, there continue to be efforts to personalize treatments to maximize patient benefit while minimizing risks. This results in refinement, rather than drastic changes to existing guidelines," Dr Pal told Medscape Medical News.

Robert J. Morgan Jr, MD, codirector of the Gynecological Cancers Program at the City of Hope, Duarte, California, agreed that the refinements to the 2016 NCCN guidelines for breast cancer will lead to more efficient and less toxic treatment.

"All NCCN guidelines are updated at least annually with meetings or conference calls of the respective committees, or more often as necessary to make certain the guidelines reflect the most important and recently published information regarding cancer treatment," Dr Morgan told Medscape Medical News.

"The updates to the breast cancer guidelines reflect this ongoing effort, which is also performed by all of the guideline subcommittees for every tumor type. Many of the changes to the guidelines will be the result of the demonstration of safer, less toxic treatment approaches as they are compared to standard treatment approaches in clinical trials," he said.

Dr Salerno, Dr Gradishar, and Dr Morgan report no relevant financial relationships.

National Comprehensive Cancer Network (NCCN) 21st Annual Conference: Presented April 1, 2016.

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