Hybrid Treatment Planning in Breast and Esophageal Cancer: A Feasible Approach for High-Volume Radiotherapy Centers.

[OBJECTIVE] To evaluate the feasibility of hybrid intensity-modulated radiotherapy (IMRT) technique in patients with esophageal and breast cancer within a high-patient volume setup.

[MATERIALS AND METHODS] A total of 36 patients with carcinoma of the left breast and esophagus were retrospectively studied with 3D-CRT, IMRT and Hybrid techniques. 3D-CRT plans for esophageal cancer consisted of one anterior-postertior (AP) and two oblique beams, while IMRT consisted of seven beams. The hybrid plan consisted of AP and PA static beams combined with five conformal beams, with a weighting ratio of 5:5 and 4:6. In breast cases, hybrid planning involved two tangential static beams and three conformal beams with a weighting ratio of 7:3. Dosimetric parameters of the hybrid-IMRT plans were then compared with those of the 3D-CRT and IMRT plans.

[RESULTS] In esophageal cancer patients, there was a significant difference found in the PTV coverage and conformity. The V20 and Dmean of left lung showed significant differences between IMRT and Hybrid IMRT. V25 and Dmean for heart showed reduced values in IMRT plan. The maximum dose to the spinal cord was higher in Hybrid IMRT compared to IMRT and 3D-CRT. In breast cancer patients, V20 and Dmean for the left lung were 23.77±4.28% and 11.09±1.70 Gy in hybrid plans; 26.50±5.06 % and 12.44±1.62 Gy in IMRT; and 25.47±5.07% and 11.52±1.54 Gy in 3D-CRT. The dose to the contralateral breast was higher in the IMRT plans.

[CONCLUSION] Considering its comparable planning time to IMRT and the added benefit of reduced OAR doses, hybrid planning could be a valuable option in high-patient-volume settings.