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Abstract

Purpose 

Conventionally fractionated postmastectomy radiation therapy (PMRT) takes approximately 5 to 6 weeks. Data supporting hypofractionated PMRT is limited. We prospectively evaluated a short course of hypofractionated PMRT, in which therapy was completed in 15 treatment days. 

Patients and Methods

We delivered PMRT at a dose of 36.63 Gy in 11 fractions of 3.33 Gy over 11 days to the chest wall and the draining regional lymph nodes, followed by an optional mastectomy scar boost of four fractions of 3.33 Gy. Our primary end point was freedom from any grade 3 or higher toxicities. We incorporated early stopping criteria on the basis of predefined toxicity thresholds. 

Results

We enrolled 69 women with stage II to IIIa breast cancer, of whom 67 were eligible for analysis. After a median follow-up of 32 months, there were no grade 3 toxicities. There were 29 reported grade 2 toxicities, with grade 2 skin toxicities being the most frequent (16 of 67; 24%). There were two patients with isolated ipsilateral chest wall tumor recurrences (2 of 67; crude rate, 3%). Three-year estimated local recurrence-free survival was 89.2% (95% CI, 0.748 to 0.956). The 3-year estimated distant recurrence-free survival was 90.3% (95% CI, 0.797 to 0.956). Forty-one patients had chest wall reconstructions; three had expanders removed for infection before radiation therapy. The total rate of implant loss or failure was 24% (9 of 38), and the unplanned surgical correction rate was 8% (3 of 38), for a total complication rate of 32%. 

Conclusion

To our knowledge, our phase II prospective study offers one of the shortest courses of PMRT reported, delivered in 11 fractions to the chest wall and nodes and 15 fractions inclusive of a boost. We demonstrated low toxicity and high local control with this schedule. On the basis of our data, we have designed a cooperative group phase III prospective, randomized trial of conventional versus hypofractionated PMRT that will activate soon.

Author information​

 Khan AJ1, Poppe MM1, Goyal S1, Kokeny KE1, Kearney T1, Kirstein L1, Toppmeyer D1, Moore DF1, Chen C1, Gaffney DK1, Haffty BG1.

1 Atif J. Khan, Sharad Goyal, Thomas Kearney, Deborah Toppmeyer, and Bruce G. Haffty, Rutgers Cancer Institute of New Jersey, New Brunswick; Dirk F. Moore and Chunxia Chen, Rutgers School of Public Health, Piscataway, NJ; Matthew M. Poppe, Kristine E. Kokeny, and David K. Gaffney, Huntsman Cancer Hospital, University of Utah, Salt Lake City, UT; and Laurie Kirstein, Memorial Sloan Kettering Cancer Center, NY.