Assessment of testicular dose during preoperative radiotherapy for rectal cancer

Fertility and reproductive concerns related to the new generation of cancer drugs and the clinical implication for young individuals undergoing treatments for solid tumors

The treatment landscape of solid tumors has changed markedly in the last years. Molecularly targeted treatments and immunotherapies have been implemented and have, in many cancers, lowered the risk of relapse and prolonged survival. Patients with tumors harboring specific targetable molecular alterations or mutations are often of a younger age, and hence future fertility and family building can be important concerns in this group. However, there are great uncertainties regarding the effect of the new drugs on reproductive functions, including fertility, pregnancy and lactation and how young patients with cancers, both women and men should be advised. The goal with this review is to gather the current knowledge regarding oncofertility and the different novel therapies, including immune checkpoint inhibitors, antibody-drug conjugates, small molecules and monoclonal antibody targeted therapies. The specific circumstances and reproductive concerns in different patient groups where novel treatments have been broadly introduced are also discussed, including those with melanoma, lung, breast, colorectal and gynecological cancers. It is clear, that more awareness is needed regarding potential drug toxicity on reproductive tissues, and it is of essence that individuals are informed based on current expertise and on available fertility preservation methods.

Incidence of Secondary Cancers After Neoadjuvant Therapy for Locally Advanced Rectal Cancer

INTRODUCTION

Whether neoadjuvant chemoradiation for locally advanced rectal cancer (LARC) induces secondary cancers is controversial. This retrospective cohort study describes the incidence of secondary cancers in LARC patients.

METHODS

We compared 364 LARC patients who received conventional (50.4 Gy) or short course neoadjuvant radiation (25 Gy x 5 fractions) followed by resection to 142 patients with surgically resected rectal cancer who did not receive radiation at a single institution from 2004 to 2018. Secondary cancer was defined as any nonmetastatic noncolorectal malignancy diagnosed via biopsy or definitive imaging criteria at least 6 mo after completion of neoadjuvant therapy or after resection in the comparison group.

RESULTS

Among the neoadjuvant radiation group (364 patients, 40% female, age 61 ± 13 y), 32 patients developed 34 (9.3%) secondary cancers. Three cases involved a pelvic organ. Among the comparison group (142 patients, 39% female, age 64 ± 15 y), 15 patients (10.6%) developed a secondary cancer. Five cases involved pelvic organs. Secondary cancer incidence did not differ between groups. Latency period to secondary cancer diagnosis was 6.7 ± 4.3 y. Patients who received radiation underwent longer median follow-up (6.8 versus 4.5 y, P < 0.01) and were significantly less likely to develop a pelvic organ cancer (odds ratio 0.18; 95% confidence interval, 0.04-0.83; P = 0.02). No genetic mutations or cancer syndromes were identified among patients with secondary cancers.

CONCLUSIONS

Neoadjuvant chemoradiation is not associated with increased secondary cancer risk in LARC patients and may have a local protective effect on pelvic organs, especially prostate. Ongoing follow-up is critical to continue risk assessment.

Effect of preoperative radiotherapy for rectal cancer on spermatogenesis

In this study, preoperative radiotherapy for rectal cancer was found to result in a dose-dependent impairment of spermatogenesis and Sertoli cell function, reflected both by decreased sperm count and characteristic changes in hormonal response, with signs of partial recovery between 12 and 24 months after surgery. Decreased semen volume was also observed, indicating ejaculatory tract dysfunction, that seemed to be longer-lasting and not related to testicular dose. This threatens fertility in men treated for rectal cancer, and suggests that pretreatment cryopreservation and anticonception after treatment should be discussed individually.

Acute primary testicular failure due to radiotherapy increases risk of severe postoperative adverse events in rectal cancer patients

AIM

The aim of this study is to analyze postoperative adverse events (AE) in relation to acute primary testicular failure after radiotherapy (RT) for rectal cancer.

METHOD

This relation was assessed in 104 men, included in a previous prospective cohort study of men treated with surgical resection of the rectum for rectal cancer stage I-III. Postoperative AE were graded according to Clavien-Dindo (2004). Grade 3 or more was set as cut-off for severe postoperative AE. The impact of primary testicular failure on postoperative AE was related to the cumulative mean testicular dose (TD) and the change in Testosterone (T) and Luteinizing hormone (LH) sampled at baseline and after RT.

RESULTS

Twenty-six study participants (25%) had severe postoperative AE. Baseline characteristics and endocrine testicular function did not differ significantly between groups with (AE+) and without severe postoperative AE (AE-). After RT, the LH/T-ratio was higher in AE+, 0.603 (0.2-2.5) vs 0.452 (0.127-5.926) (p = 0.035). The longitudinal regression analysis showed that preoperative change in T (OR 0.844, 95% CI 0.720-0.990, p = 0.034), LH/T-ratio (OR 2.020, 95% CI 1.010-4.039, p = 0.047) and low T (<8 nmol/L, OR 2.605, 95 CI 0.951-7.139, p = 0.063) were related to severe postoperative AE.

CONCLUSION

Preoperative decline in T due to primary testicular failure induced by preoperative RT could be a risk factor regarding short-term outcome of surgery in men with rectal cancer.

Incidence of second tumors after treatment with or without radiation for rectal cancer

Background

The aim of this study was to analyze the association between radiation therapy (RT) for rectal cancer and the development of second tumors.

Patients and methods

Data on all surgically treated non-metastatic primary rectal cancer patients diagnosed between 1989 and 2007 were retrieved from the Netherlands population-based cancer registry. Fine and Gray's competing risk model was used for estimation of the cumulative incidence of second tumors. Multivariable analysis was conducted using Cox regression.

Results

The cohort consisted of 29 027 patients of which 15 467 patients had undergone RT. Median follow-up was 7.7 years (range 0-27). Among all 4398 patients who were diagnosed with a second primary tumor, 1030 had one or more pelvic tumors. The standardized incidence risk for any second tumor was 1.16 (95% confidence interval [CI] 1.12-1.19), resulting in 27.7/10 000 excess cancer cases per year in patients treated for rectal cancer compared with the general population. RT reduced the cumulative incidence of second pelvic tumors compared with patients who did not receive RT (subhazard ratio [SHR] 0.77, CI 0.68-0.88). Second prostate tumors were less common in patients who received RT (SHR 0.54, CI 0.46-0.64), gynecological tumors were more frequently observed in patients who received RT (SHR 1.49, CI 1.11-2.00).

Conclusions

Patients with previous rectal cancer had a marginally increased risk of a second tumor compared with the general population. Gynecological tumors occurred more often in females who received RT, but this did not result in an overall increased risk for a second cancer. RT even seemed to have a protective effect on the development of other second pelvic tumors, pre-dominantly for prostate cancer. These findings are highly important and can contribute to improved patient counseling.