Long-term impact of preoperative radiotherapy for rectal cancer on testicular function

The aim was to assess long-term impact of preoperative radiotherapy (RT) for rectal cancer on testicular function, its clinical relevance regarding sexual function and cancer-related events.

This analysis of an original cohort with longitudinal design included 163 men with rectal or prostate cancer stage I-III treated with surgery in Stockholm, Sweden, between 2010 and 2014. Exposure to RT (n = 91) was quantified by cumulative mean testicular dose. Repeated measurement of serum Testosterone (T), free T and Luteinizing hormone (LH) respectively questionnaires of sexual function (IIEF and AMS) were collected before treatment (baseline), one and two years postoperatively. Data on cancer recurrence were collected from medical records during the standard five-year cancer follow-up. Association between hormone levels and patient reported outcome measures for sexual function was assessed by linear random-effect models with final analysis adjusted for age, BMI and ASA-score.

Testicular dose was associated with a preoperative decline in T and free T, with a consecutive increase in LH and LH/T ratio during the study period. Not all androgen levels recovered within two years. Testosterone levels were associated with patient reported outcome measures for sexual function. Elevated LH one year after surgery for rectal cancer was associated with a three-times increased risk for cancer recurrence.

Endocrine testicular function is related to sexual symptoms in men treated for rectal- or prostate cancer. Monitoring of testicular function in these patients could be valuable to improve interventions for treatment-related sexual dysfunction. The association between elevated LH and cancer recurrence requires further investigation.