Comparison of testicular dose delivered by intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) in patients with prostate cancer

Abstract

Introduction A small decrease in testosterone has been documented after prostate irradiation, possibly due to incidental dose to the testes. Testicular dose from prostate external beam radiation plans with either IMRT or VMAT were calculated to investigate any difference. Methods Testicles were contoured for 16 patients being treated for localized prostate cancer. Two plans were created for each patient, one with IMRT and one with VMAT. No specific attempt was made to reduce testicular dose. Minimum, maximum and mean dose to the testicles was recorded for each plan. Results Of the 16 patients, 4 received a total dose of 7800cGy to the prostate alone, 7 received 8000cGy to the prostate alone, and 5 received 8000cGy to the prostate and pelvic lymph nodes. The mean (range) of the mean testicular dose with an IMRT plan was 54.7cGy (21.1-91.9) and 59.0cGy (25.1-93.4) with a VMAT plan. In 12 cases, mean VMAT dose was higher than mean IMRT dose, with a mean difference of 4.3cGy (p=0.019). Summary There was a small, but statistically significant increase in mean testicular dose delivered by VMAT compared with IMRT. Despite this, it unlikely that there is a clinically meaningful difference in testicular dose from either modality.

Testosterone Levels and Sexual Quality of Life After Stereotactic Body Radiation Therapy for Prostate Cancer: A Multi-Institutional Analysis of Prospective Trials

“…Although stereotactic body radiation therapy (SBRT) has been recognized as a standard treatment option for lowand intermediate-risk prostate cancer, 1,2 concerns regarding the sequelae of hypofractionation remain. [3][4][5] The proximity and radiosensitivity of the testes raises concern for reduced testicular function and impaired quality of life after SBRT. 6 The impact of conventionally fractionated radiation therapy on testosterone levels is itself unclear, with reports of posteradiation therapy testosterone ranging from insignificantly changed 7,8 to transiently depressed 9,10 and even permanently decreased.…”

Colorectal cancer conventional radiotherapy treatment technique with sparing the testicles

“…The possible reasons were the dosimeter has been moved or the testicles have been in different position during the treatment session [16]. Various studies have shown that the distance of the testicles from the lower border of the radiation field is the most important factor affecting testicular dose [8,14,[17][18][19]. Herman, et al showed that the percentage of the dose testicles received due to the scattered radiation is inversely proportional to the distance of the testicles from the lower border of the radiation field [8].…”

Radiotherapy in testicular germ cell tumours – a literature review

“…In the study performed by Martin et al ., among 12 cases of prostate cancer, the mean dose delivered with VMAT was higher than the dose delivered with IMRT. The difference was 4.3 Gy ( p = 0.019) and was statistically significant [ 38 ].…”