A comparison of radiotherapy treatment planning techniques in patients with rectal cancers by analyzing testes doses.

PURPOSE

To evaluate the target volume (TV) and critical organ doses with priority of testes with the comparison of conformal radiotherapy (CRT), dynamic intensity-modulated radiotherapy (DIMRT), and volumetric modulated arc therapy (VMAT) techniques.

MATERIALS AND METHODS

CRT, DIMRT, and VMAT techniques were generated on computed tomography images in prone position of 10 male patients with distal rectal cancer. Conformity index (CI), heterogeneity index (HI), treatment time, and monitor units were examined; dose-volume-histograms (DVHs) for the TV and the organs at risk (OARs) were evaluated.

RESULTS

Target dose coverage of all treatment plans was similar. HI and CI values for DIMRT and VMAT were closer to "1" compared to CRT. DVH parameters for OARs were decreased with DIMRT and VMAT compared to CRT. The percent volume (V) of 3 Gy dose of testes was 62.01% (±25.45%), 42.68% (±16.42%), and 35.89% (±14.97%) in the CRT, DIMRT, and VMAT techniques, respectively. V of testes decreased with VMAT compared to CRT and DIMRT (P = 0.008 and P = 0.051, respectively).

CONCLUSION

Modern radiotherapy techniques are superior to conformal techniques in planning quality parameters and sparing OARs. DIMRT and VMAT could be considered instead of CRT in the desire to preserve fertility of patients with rectal cancer.