Abstract

INTRODUCTION

Adjuvant radiotherapy is the standard treatment for breast cancer patients who underwent breast conserving surgery. One of the most important factors affecting cosmetic results after radiotherapy is breast size. The aim of this study was to evaluate the cosmesis and dosimetric distribution of patients undergoing radiotherapy in the prone position due to pandular breast.

METHODS

Between July 2015 and August 2017, 17 patients who had breast conserving surgery and radiotherapy were evaluated. Patients were simulated in prone position. Fifty Gy to the breast; median 14 Gy (10-16 Gy) boost to the tumor bed were applied. Dosimetric results were evaluated from treatment planning system. Acute and late side effects were evaluated by using RTOG toxicity criteria.

RESULTS

Seventeen patients with pendulous breasts who underwent breast conserving surgery and radiotherapy were evaluated. The mean age was 59 (38-87); mean tumor size was 2.2 cm (0.7-5.5 cm). Median 50 Gy (48-50 Gy) radiotherapy was applied to the whole breast with a median 14 Gy (10-16 Gy) boost to the tumor bed. PTV minimum, maximum and mean doses were 3341 cGy, 5544 cGy, 5161 cGy; mean dose of lung and V5, V20, V30 values were 414 cGy, 10.5%, 5%, 3.6%; hear tmean dose and V5, V10, V30 values were; 256cGy, 7.7%, 3.3%, 1.2%; maximum and mean doses of the contrlateral breast were 1128 cGy and 44 cGy. In 7 patients grade 2 radiodermitis; in 1 patient grade 3 radiodermitis was observed. There was no recurrence or poor cosmetic outcome during the14.5 months follow-up (1-24 months).

DISCUSSION AND CONCLUSION

More dose inhomogenity is seen in the supine position radiotherapy of pendulous breasts and as a result bad cosmetic results may be observed. Also lung and heart toxicity increases with the irradiation of large areas. Good dose homogenities and cosmetic results may be achieved by prone position.