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To hypofractionate or not to hypofractionate: That is the question

10/25/2017

 
PictureBenjamin D. Smith, MD, Associate Professor of Radiation Oncology and Health Services Research at The University of Texas MD Anderson Cancer Center.
By Benjamin D. Smith, MD, Chair of ASTRO’s Clinical Affairs and Quality Committee
 
In 2011, ASTRO published a clinical practice guideline on fractionation for whole breast irradiation. The primary purpose of this guideline was to synthesize the evidence regarding dose-fractionation from the available randomized clinical trials and thus to provide practical advice to radiation oncologists. At this time, the 10-year data from the NCIC (Canadian) trial had just been published, and the data from the START B trial had been published but with only six years follow-up.
 
The NCIC trial, though an excellent study, did not include a tumor bed boost nor did it include patients treated with more modern chemotherapy regimens, including anthracyclines, taxanes or trastuzumab. These issues, at the time, were considered to limit the external validity of this trial when applied to practice in the United States. Further, while the START B trial addressed these limitations, the lack of long-term follow-up from this trial was still a bit of a concern.
 
In light of the totality of the evidence at that time, the writing panel opted to define a group of patients for whom there was high confidence that hypofractionated whole breast irradiation and conventionally fractionated whole breast irradiation were equivalent. This group was considered women age 50 and older with pT1/2 N0 breast cancer, not receiving chemotherapy, for whom dose homogeneity goals could be achieved and in whom the heart could generally be excluded from the high-dose region.
 
These recommendations, while well-intended, now in retrospect seem conservative. In 2013, the long-term results of the START A and B trial were published. They demonstrated no evidence of an effect of chemotherapy, tumor bed boost or patient age on choice of dose-fractionation. There was also no evidence of a deleterious effect of hypofractionation on cardiac mortality. Armed with the long-term START A and B data, many practitioners, including myself, chose to more fully embrace hypofractionation as the preferred standard of care in patients receiving whole breast irradiation.
 
The patient mentioned in the recent NPR piece published by Liz Szabo had received chemotherapy. While in my personal opinion chemotherapy should not preclude use of hypofractionation, it should be remembered that the currently valid ASTRO guideline does not endorse a preferred dose-fractionation scheme in patients treated with chemotherapy. In essence, the current guideline suggests that either choice may be valid, and the panel deferred making a strong recommendation. Within this context, the patient’s physician is on stable ground to recommend conventional fractionation. However, I would encourage all physicians to engage patients in a process of shared decision-making, particularly in the setting of evolving treatment guidelines, to ensure the decisions are adequately personalized.
 
Within this setting, I think a couple points should be made. First, I believe in my heart that radiation oncologists who are treating patients with conventionally fractionated whole breast irradiation are not motivated by financial considerations. Rather, I believe these physicians are recommending the treatment they feel is best for their patient—best with regard to long-term toxicity and local-regional control. Practicing radiation oncologists are very cognizant of the fact that radiation delivery is irreversible, and we are very attuned to the potential effects of higher doses in shorter time frames, particularly late effects.
 
Thus, if a new treatment arises that provokes concern regarding late effects, it is understandable that a radiation oncologist may be reluctant to quickly adopt it. Second, while the reluctance to adopt hypofractionated whole breast irradiation may be very well-intended, what may be forgotten in this calculus is the harm of conventional fractionation. Two to three extra weeks of radiation may be very problematic to a patient—in terms of lost work, lost wages, lost time in caregiving roles and higher health care spending. In addition, research conducted at MD Anderson, my employer, showed that patients treated with conventional fractionation suffer a higher burden of acute toxicity, and they still have more fatigue six months post-radiation than patients treated with hypofractionation. These findings strongly underscore the relative harm of conventional fractionation relative to hypofractionation and, correspondingly, the value of hypofractionated whole breast irradiation.
 
To respond to the new literature, ASTRO has nearly completed an updated guideline on whole breast irradiation that will supersede the prior guideline. I hope that this new guideline will offer pragmatic assistance to well-intended clinicians, helping to synthesize the existing evidence and frame the literature to facilitate high quality shared decision-making.

What's your take on conventionally fractionated versus hypofractionated radiation therapy for breast cancer? Tell us in the comments.

Kathi Kolb
10/26/2017 05:30:58 pm

Thank you very much, Dr. Smith, for responding to the article by Ms. Szabo and for your understanding of the very considerations I discussed with her. I was very grateful to have discovered the Canadian research on the shorter protocol right about the time I was scheduling treatment for myself; that my radiation was taking place at a teaching hospital; and that my radiation oncologist was familiar with the protocol and felt comfortable doing it. Also, thank you for expanding on radiation options with patients who've had chemo. I appreciate your taking the time to address these issues.

Ben Smith
10/30/2017 11:32:10 am

Dear Ms Kolb,

Thank you for your kind comments. I am honored every day to devote my life to giving my patients the best possible treatment for their breast cancer.

Sincerely,
Ben

Mike Betz
11/4/2017 08:50:21 am

Thank you for the thoughtful commentary, Dr Smith. I'm very much looking forward to the ASTRO update and to its hopefully sparking a much-needed renewed discussion of the subject in our community worldwide.
In my center (in Lausanne, Switzerland), we introduced hypofractionation in early 2013 after the START B 10-yr data was presented in San Antonio, and rapidly expanded it thereafter (we now use it pretty much exclusively for all our early breast cancer patients). After nearly 5 years of experience with hypofractionated breast RT, there is no question in my mind that it is the better schedule, and our patients love it. However, we remain one of the few Swiss centers to have introduced hypofractionation as standard, and it's been a constant uphill battle to inform and educate colleagues from other disciplines when they continue to generally receive the message from many in our community that hypofractionated schedules should be reserved for frail, elderly patients. This has continued to be the case even after the Jan, 2016 update to the NCCN recommendations making hypofractionation the "NCCN-preferred standard" for whole-breast RT.
While I share your belief that most colleagues have the interest of their patients at heart, I also believe that billing considerations unfortunately continue to play a great role in driving resistance to hypofractionation (as they do to single-fraction treatment of bone mets). In one center I know of, a friend of mine was recently confronted with a fraction/patient analysis of her prescribing practices, implying that these were problematic from a budgetary standpoint when compared with those of her colleagues who do not use hypofractionation (as she does). Well-intentioned or not, physicians may not always be free to call the shots given the per-fraction reimbursement models currently in place in many regions, and may find themselves having to choose between hypofractionating and keeping their jobs.
I just this week saw the upcoming ASTRO guideline concerning hypofractionation for prostate cancer, which in its draft version is strongly in favor for all risk categories, with a high-level of evidence, and is going to open a whole new can of worms. Given the considerations just mentioned, increasing the quality of care in prostate as in breast cancer will unfortunately require a certain amount of personal courage on the behalf of many physicians in the absence of new reimbursement models

Ben Smith
11/6/2017 08:07:29 pm

Thank you for your thoughtful reply. The traditional fee-for-service models discourage innovation along the lines of value and cost. This is to our patients' detriment. As a specialty, I think we must have the courage to go where the evidence leads us and put our patients' interests ahead of our own, as you eloquently describe.

Mike Betz
11/12/2017 02:44:07 pm

Thank you for your equally eloquent response. I read with great interest Dr. Kavanagh's congressional testimony last week, presenting ASTRO's proposal to replace the current fee-for-service model with an alternative payment model based on care episodes, with reimbursement contingent on guideline-adherent care. Getting it in place by the end of 2018 certainly seems ambitious, and I do wonder how it will be received in the US radiation oncology community at large. Even though I won't be directly affected (and as far as I know nothing comparable is likely to be on the table in Switzerland in the foreseeable future), I wish you luck and will be following with great interest.


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