A Randomized Trial Comparing Two Fractionation Schedules for Breast Irradiation Postlumpectomy in Node-Negative Breast Cancer

William Levin, MD
OncoLink Assistant Editor
Last Modified: May 22, 2000

Presenter: Timothy J. Whelan
Affiliation: Hamilton Regional Cancer Ctr, Hamilton, ON, Canada; Toronto Sunnybrook Regional Cancer Ctr, Toronto, ON, Canada; McMaster Univ, Hamilton, ON, Canada; Kingston Regional Cancer Ctr, Kingston, ON, Canada; Ottawa Regional Cancer Ctr, Ottawa,

Many women with early stage breast cancer choose lumpectomy plus definitive breast irradiation for treatment. Typically in the US, radiation is delivered to a dose of 46 - 50 Gy to the whole breast followed by a boost to about 60 Gy, all over a course of 6 weeks. This study evaluates the possibility of increasing the daily fraction size and reducing the number of treatment days by using a dose that is biologically equivalent to standard therapy.

Materials and Methods:

  • 1234 women with node negative breast cancer and clear surgical margins following lumpectomy were randomized to either:
    Arm 1. 42.5 Gy of whole breast irradiation in 16 fractions over 22 days
    Arm 2. 50 Gy of whole breast irradiation in 25 fractions over 35 days

  • All treatment was delivered 5 days per week with 2 tangential fields

  • No breast boost was used in this study

  • Median followup was 4.6 years

  • The 5-year actuarial breast recurrence rate was 2.9% in each arm.

  • The 5-year diease-free survival rates were 88% vs. 90% (p=NS) in Arm 1 vs. Arm 2.

  • The 5-year overall survival was 93.5% vs. 94.3% (p = NS) in Arm 1 vs. Arm 2.

  • The cosmetic outcome at both 3 and 5 years was not significantly different.
Authors' Conclusions

  • These data suggest that a shorter course of radiation is an acceptable alternative to the current standard of practice.

  • Such a schedule is more attractive because it is more convenient for patients and less resource-intensive for the facility.
Clinical/Scientific Implications:

  • In general, increasing the daily radiation dose can be associated with worse cosmetic outcome and a higher probability of normal normal tissue complications involving the heart, brachial plexus and lung.

  • The control arm of this trial did not use a breast boost typically administered at most US centers.

  • This study shows an equal efficacy in tumor control and cosmetic outcome between the two arms.

  • The relatively short followup of this study must be taken into account when evaluating for local control, late toxicity and cosmesis.


Catherine and Finn
by OncoLink Editorial Team
December 01, 2015