Ultra- Hypofractioned Radiation Therapy Treatment to Whole-Breast for Early-Stage Breast Cancer: Optimal Standard of Care
Abstract
Purpose
Radiation therapy is utilized as an adjuvant treatment after breast conserving surgery in early-stage breast cancer patients. There are several protocols available for management of early-stage breast cancer. The purpose of the study is to present a dosimetric narrative of ultra-hypofractionated (Fast-Forward) and moderately hypofractionated (Fast) treatment regimen. A well established method of treatment delivers 4256cGy in 16 fractions over approximately three weeks, which has been proven to work as well as longer conventionally fractioned treatment schedules. Recently, even shorter treatment regimens delivering 2600cGy in 5 fractions over one week has been shown to be as effective and safe as moderately hypofractionated treatment schedules.
Methods
This study includes 30 left sided supine breast cases. The review compares radiation dose distribution plans from patients treated with 266cGy per fraction for 16 fractions (hypofractionated) and 520cGy per fraction for 5 fractions (ultra-hypofractionated) using same planning target volume (PTV)_Left Breast. Radiation treatment plans utilize 6x beam energy with 3-dimensional tangent beams using field-in-field technique.
Results
Outcome demonstrated that the dose distribution in isodose lines representation remains similar. PTV coverage was slightly reduced due to acceptance of lower hot-spot for fast forward treatment plans. Dose Volume Histogram (DVH) values were analyzed and Normal Tissue Complication Probability (NTCP) were calculated based on mathematical model. Model results indicated that biologically effective dose is comparable for heart and lung for both treatment plan schedules. NTCP results were very small and as low as 1%, making them insignificant.
Conclusion
The review suggests that the ultra-hypofractionated radiation therapy plans using 2600cGy in 5 fractions offer similar and safe dosimetric results compared to the 4256cGy in 16 fractions treatment schedule. Despite the fact that the16-fraction schedule has longer follow-up data, the 5-fraction schedule is a safe option available to patients offering a reduced treatment duration.