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Shorter Radiation Schedule as Effective as Standard

10-year follow-up of two trials shows less radiation, given in fewer doses of greater amounts per dose over fewer weeks, is as safe and effective as today’s standard of care

November 27, 2013

Written By Nicole Katze, MA, Editor and Manager, Publications
Reviewed By Suzanne B. Evans, MD, MPH

An analysis of 10 years of data from the UK Standardization of Breast Radiotherapy (START) trials A and B shows women with early-stage breast cancer may be able to have radiation therapy for a shorter amount of time, yet get the same treatment benefit.

Trial participants receiving today’s standard-of-care radiation therapy had the same risk of the breast cancer coming back and level of treatment side effects as those treated with less radiation overall, in fewer doses of greater amounts of radiation per dose, over fewer weeks.

Background and Design

Generally, women with early-stage breast cancer who have radiation therapy after breast surgery are given 25 doses of 2 gray of radiation over 5 weeks. One gray is one unit of radiation.

The START trials compared outcomes of a group of women receiving standard radiation therapy with outcomes of two other treatment groups receiving less overall radiation given in greater amounts per dose, in fewer doses. The outcomes assessed were:

  • rates of loco-regional recurrence, breast cancer that returned in the breast, the chest wall, near the collar bone or in the armpit on the same side as the breast cancer
  • the severity of side effects to healthy tissue as shown by breast shrinkage, hardening, swelling and the appearance of blood vessels on the surface of the skin
  • rates of local recurrence, cancer returned to the breast or chest wall
  • rates of distant recurrence, cancer that spread to distant parts of the body
  • rates of disease-free survival, the time from starting treatment to any kind of recurrence, and
  • rates of overall survival, the time from starting treatment to death from any cause

In START-A, 2,236 UK women with early-stage breast cancer were recruited from 17 cancer centers between January 1999 and December 2002. They were between the ages of 25 and 85, already had lumpectomy or mastectomy to remove the breast tumor, and were scheduled to have radiation therapy as part of their regular treatment. Women in START-A were randomly assigned to receive

  • standard therapy of 25 doses of 2 gray of radiation, given over 5 weeks, or
  • 13 doses of 3.2 gray of radiation, given over 5 weeks, or
  • 13 doses of 3.0 gray of radiation, given over 5 weeks

In START-B, 2,215 women from 23 cancer centers were recruited between January 1999 and October 2001. They were between the ages of 23 and 86, and met the same requirements as the women in START-A. The women in START-B were randomly assigned to receive

  • standard therapy of 25 doses of 2 gray of radiation, given over 5 weeks, or
  • 15 doses of 2.67 gray of radiation, given over 3 weeks

Participants enrolled in the trials had to have a very even dose of radiation sent through the breast, which is harder to achieve in larger bust sizes. Because of this, women who had larger breasts were not included in this study. Current technology, however, makes it possible for the delivery of radiation to be tailored so that it is evenly sent through larger breasts.

5-Year Results

At 5-years of follow-up, researchers found treatment with greater daily amounts of radiation given in fewer treatments over shorter time periods was as effective at preventing the cancer from returning as a local or loco-regional recurrence as less daily radiation doses given in more treatments over the standard 5 weeks, and had similar side effects on normal tissue.

10-Year Results

The present study reported on the final 10-year data from the START trials and found:

  • In START-A and START B, there was no significant difference in loco-regional recurrence in any of the treatment groups. This means that the greater amounts of radiation per dose received by participants in fewer doses had the same effects as the standard therapy.
  • In both trials, the most common side effects to normal tissue were breast shrinkage and hardening. Breast shrinkage occurred less frequently in the 3 week arm in the START-B trial.

What This Means for You

Ten-year follow-up data are important in clinical trials for breast cancer. They show the long-term impact of the study treatment or therapy. In this case, findings suggest you may be able to reduce the number of days you receive radiation treatments, if you receive less radiation overall in greater amounts, in fewer doses during each visit.  

Know that your doctor will have to give the radiation in a similar way to how it was given in the trial to expect the same results. Breast size may affect whether this is possible.

Fewer appointments may mean more time for the other important activities in your life. You may also find comfort in knowing that shortening the treatment period you receive radiation does not have a negative impact on the treatment’s ability to prevent recurrence. In addition, this study suggests that receiving less radiation overall, in fewer doses of greater amounts of radiation per dose, may lower the occurrence of side effects like breast shrinkage or hardening.

Talk with your radiation oncologist about the pros and cons of radiation therapy, what side effects to expect, and why he or she recommends a certain course of treatment. If you have concerns, share them openly.

Haviland, J, Owen, J, Dewar, J, Agrawal, R, Barrett, J, Barrett-Lee, P, et al. The UK standardization of breast radiaotherapy (START) trials of radiotherapy hypofractionation for treatment of early breast cancer: 10-year follow-up results of two randomized controlled trials. The Lancet (2013); 14 (11): 1086-1094.

Denver, CO  ·  September 13, 2014

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