Risk of Hypogonadism From Scatter Radiation During Pelvic Radiation in Male Patients With Rectal Cancer

Insights Into Antioxidant Strategies to Counteract Radiation-Induced Male Infertility

Significance: Radiotherapy, which employs ionizing radiation to destroy or prevent the multiplication of tumor cells, has been increasingly used in the treatment of neoplastic diseases, especially cancers. However, radiation collaterally leads to prolonged periods of sperm count suppression, presumably due to impaired spermatogenesis by depleting the germ cell pool, which has long-term side effects for male reproduction. Recent Advances: Studies of antioxidant compounds as a potential strategy for male fertility preservation have been performed mainly from animal models, aiming to prevent and restore the male germinal tissue and its function, particularly against the oxidative stress effects of radiation. Evidence in preclinical and clinical trials has shown that inhibitors of the renin-angiotensin system and other drugs, such as statins and metformin, are candidates for ameliorating radiation-induced damage to several tissues, including the testis and prostate. Critical Issues: Research for developing an ideal radioprotective agent is challenging due to toxicity in the normal tissue, tumor radioresistance, cellular response to radiation, costs, regulation, and timeline development. Moreover, male radioprotection experiments in humans, mainly clinical trials, are scarce and use few individuals. This scenario is reflected in the slow progress of innovation in the radioprotection field. Future Directions: Expanding human studies to provide clues on the efficacy and safety of radioprotective compounds in the human reproductive system is necessary. Drug repurposing, frequently used in clinical practice, can be a way to shorten the development pipeline for innovative approaches for radioprotection or radiomitigation of the repercussions of radiotherapy in the male reproductive system.

The Long-Term Effect of Intensity Modulated Radiation Therapy for Prostate Cancer on Testosterone Levels

Purpose

Concern about a long-term effect of the delivery of intensity modulated radiation therapy (IMRT) for prostate cancer on serum testosterone levels remains unelucidated. We evaluated how IMRT for localized prostate cancer affects serum testosterone levels during a follow-up period of up to 10 years.

Methods and Materials

We retrospectively evaluated data from 182 patients with localized prostate cancer who underwent definitive IMRT alone between 2007 and 2014. Serum total testosterone (TT) levels were measured by blood draws between 6 AM and 11 AM before treatment and at every posttreatment follow-up for 10 years. Pretreatment values and each posttreatment testosterone value were compared using a Wilcoxon signed rank test. The data set was stratified into 4 groups based on the pretreatment testosterone (pre-TT) values using quartiles.

Results

The median absolute or relative changes in TT levels from pretreatment were –0.42 ng/mL or –12.0% at 3 months after radiation therapy (P < .0001). Subsequently, TT levels gradually recovered to nearly the pretreatment levels 24 to 36 months after IMRT. When analyzed according to the pre-TT quartile, median TT levels initially decreased at the 3- to 12-month period in all the quartiles; however, median TT levels increased from the 18-month period in the first and second quartile groups, whereas they were maintained at less than the pretreatment levels in the third and the fourth quartile groups throughout the entire decade after radiation therapy. The proportion of patients with hypogonadal status, defined as TT levels <3.00 ng/mL, did not increase over time.

Conclusions

A transient and modest decrease of TT levels after IMRT spontaneously recovered to the pretreatment levels at the 24- to 36-month period except in patients in the higher quartile of pre-TT. This might have been partly owing to a variable sensitivity of individual testicular function to scattered radiation. Patients with lower pre-TT did not demonstrate a progressive overall rate of hypogonadism until 10 years after radiation therapy.

Epidemiology of Male Hypogonadism

The epidemiology of male hypogonadism has been understudied. Of the known causes of endogenous androgen deficiency, only Klinefelter syndrome is common with a likely population prevalence of greater than 5:10,000 men (possibly as high as 10-25:10,000). Mild traumatic injury might also be a common cause of androgen deficiency (prevalence 5-10:10,000 men), but large, long-term studies must be completed to confirm this prevalence estimation that might be too high. The classic causes of male androgen deficiency-hyperprolactinemia, pituitary macroadenoma, endogenous Cushing syndrome, and iron overload syndrome-are rare (prevalence < 10,000 men).

Utilization of brachytherapy in Quebec, Canada

BACKGROUND AND PURPOSE

Despite the excellent clinical outcomes from brachytherapy treatments compared with other modalities and the low associated costs, there have been reports of a decline in utilization of brachytherapy. The aim of this study was to investigate in detail the trend in utilization of brachytherapy in the province of Québec, Canada, from 2011 to 2019.

MATERIALS AND METHODS

All radiotherapy clinics in the province of Quebec, and among these the clinics that provide brachytherapy treatments, were identified. This observational retrospective cohort study involved analysis of data compiled by the Ministère de la Santé et des Services Sociaux du Québec for the period of 2011 to end of 2019 on all brachytherapy procedures performed in the province of Quebec. Time series graphs were used to describe the number of high dose rate (HDR) and low dose rate (LDR) brachytherapy treatments during the studied time period. Statistical analysis was conducted using R statistical software.

RESULTS

Between 2011 and 2019, 12 hospitals in the province of Québec provided radiotherapy treatments, and all of them offered brachytherapy services. The median annual number of brachytherapy sessions was 4413 (range 3930-4829). HDR brachytherapy represented over 90% of all brachytherapy treatments throughout the study period. Significant changes over time were observed in the number of treatments: at least 5% change was seen only for the two most common subtypes of brachytherapy, HDR interstitial and HDR intracavitary, with an increase of 9.6% and a decrease of 9.2%, respectively. The use of other subtypes of brachytherapy (HDR-plesiotherapy, LDR-interstitial, LDR-intracavitary, LDR-eye plaque) was stable between 2011 and 2019, with ≤ 2.5% variation.

CONCLUSION

This study demonstrates an overall steady use of brachytherapy between 2011 and 2019 in Quebec. Brachytherapy offers numerous advantages for the treatment of diverse cancer sites. Although more sophisticated external beam radiotherapy treatments have emerged in the last decades, the precision and cost-effectiveness of brachytherapy remain unbeaten. To ensure the continued use and availability of brachytherapy, governments must put in place policies and regulations to that effect. Training and exposure of future health care professionals to brachytherapy within Quebec and Canada is essential to provide all patients the same access to this life saving modality.

Involved Site Radiotherapy Extends Time to Premature Menopause in Infra-Diaphragmatic Female Hodgkin Lymphoma Patients - An Analysis of GHSG HD14- and HD17-Patients

Introduction

Consolidation radiotherapy in intermediate stage Hodgkin´s lymphoma (HL) has been the standard of care for many years as involved field radiotherapy (IFRT) after chemotherapy. It included initially involved region(s). Based on randomized studies, radiation volumes could be reduced and involved site radiation therapy (ISRT) became the new standard. ISRT includes the initially affected lymph nodes. In young adults suffering from HL, infertility and hypogonadism are major concerns. With regard to these questions, we analyzed the influence of modern radiotherapy concepts such as consolidating ISRT in infradiaphragmatic involvement of HL after polychemotherapy.

Patients and Methods

Five hundred twelve patients treated within German Hodgkin Study Group (GHSG) HD14 and HD17 trials were evaluated. We analyzed log-adjusted follicle-stimulating-hormone (FSH)- and luteinizing-hormone (LH)-levels of HD14-patients with infradiaphragmatic radiotherapy (IDRT) in comparison with HD14-patients, who had a supradiaphragmatic radiotherapy (SDRT). In a second step, we compared IFRT with ISRT of female HD17 patients regarding the effects on ovarian function and premature menopause.

Results

We analyzed FSH- and LH-levels of 258 female and 241 male patients, all treated with IFRT. Of these 499 patients, 478 patients had SDRT and 21 patients had IDRT. In a multiple regression model, we could show that log-adjusted FSH (p=0.0006) and LH values (p=0.0127) were significantly higher after IDRT than after SDRT. The effect of IDRT on gonadal function was comparable to two cycles of escalated bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (BEACOPPesc). We compared the effect of IFRT with ISRT in thirteen female HD17 patients with infradiaphragmatic (ID) involvement. The mean ovarian dose after ISRT was significantly lower than after IFRT. The calculated proportion of surviving non-growing follicles (NGFs) increased significantly from 11.87% to 24.48% in ISRT compared to IFRT, resulting in a significantly longer calculated time to menopause. The younger the age at therapy, the greater the absolute time gain until menopause.

Conclusion

Infradiaphragmatic IFRT impairs gonadal function to a similar extent as two cycles of BEACOPPesc. In comparison, the use of ISRT target volume definition significantly reduced radiation dose to the ovaries and significantly extends the time interval from treatment to premature menopause.

Prevalence of erectile dysfunction in male survivors of cancer: a systematic review and meta-analysis of cross-sectional studies

Background

Prevalence of erectile dysfunction (ED) in male survivors of cancer across cancer types has not been systematically analysed.

Aim

To estimate the prevalence of ED in all types of cancer and identify characteristics associated with ED in survivors of cancer.

Design and setting

Systematic review and meta-analysis (MA) of cross-sectional studies.

Method

MEDLINE, CINAHL, PsycINFO, and EMBASE were searched, targeting reports published from inception to 1 February 2020. All retrospective or prospective studies reporting prevalence of ED in male patients with cancer and using a validated tool for detection of ED were included. A random-effects MA model was used to pool prevalence of ED as absolute estimates at three different stages, that is, ‘healthy’, ‘at diagnosis’, and ‘after treatment’. A univariate MA regression including the three-level group variable as the only independent variable was used to assess the difference in ED prevalence across the three groups. Further MAs were conducted for studies involving patients at diagnosis and after treatment, and statistical inferences were made with setting for multiple testing controlling for a false discovery rate (FDR) <0.05.

Results

In total, 1301 studies were assessed for inclusion. Of these, 141 were potentially eligible and subsequently scrutinised in full text. Finally, 43 studies were included with a total of 13 148 participants. Overall, pooled data of the included studies showed an ED prevalence of 40.72% (95% confidence interval [CI] = 31.80 to 50.29) in patients with cancer, with prevalences of 28.60% (95% CI = 12.10 to 53.83) at time of diagnosis and 42.70% (95% CI = 32.97 to 53.03) after treatment, with significant difference between these two stages and across cancer locations, controlling for an FDR <0.05.

Conclusion

Erectile dysfunction was particularly high in male survivors of cancer and was associated with cancer treatment, cancer site, and age.

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.

Prolonged hormonal therapy and external beam radiation independently increase the risk of Persistent Hypogonadism in men treated with prostate brachytherapy

PURPOSE

To identify variables that predict persistent hypogonadism and castration in patients with prostate cancer (PCa) treated with brachytherapy (BT).

MATERIALS AND METHODS

A retrospective analysis was performed on 1,053 patients receiving BT ± external beam radiation therapy (EBRT) ± hormone therapy (HT) for NCCN low, intermediate, or high-risk PCa between 1990 and 2011. Patients were categorized as not receiving HT (n = 438, 41.6%), ≤6 months (n = 317, 31.1%) or > 6 months (n = 298, 28.3%) of HT. 572 (54.3%) received BT alone, and 481 had combination therapy. The five- and 10-year freedom from persistent hypogonadism (T < 280 ng/dL) and castration (T < 50 ng/dL) for each group was evaluated with Kaplan-Meier estimates. Multivariable cox proportional hazards models were used to compare the risk of persistent hypogonadism and castration at a median followup of 6.5 years (posttreatment to final T) (IQR: 4.3-9.1 years; range: 1.0-19.2 years).

RESULTS

The 5-year freedom from hypogonadism rates were 92.4%, 88.9%, and 87.0% for patients with no HT, ≤ 6 months and >6 months of HT, respectively (10-year rates: 66.7%, 55.3%, 40.5%); p < 0.01. The 5-year freedom from castration rates were 99.2%, 98.0%, and 98.4%, respectively (10-year rates: 97.9%, 95.5%, 90.9%); p = 0.078. Number of months of HT (HR = 1.04, p = 0.030) and BT with EBRT vs. BT alone (HR = 1.56, p = 0.010) significantly increased the risk of persistent hypogonadism. Number of months of HT was the only variable which increased the risk of persistent castration (HR = 1.09, p = 0.014).

CONCLUSIONS

The addition of EBRT to BT is an independent risk factor for persistent hypogonadism. Prolonged HT additionally increases the risk of persistent hypogonadism and castration.

A systematic review of radiation-induced testicular toxicities following radiotherapy for prostate cancer

BACKGROUND

Prostate cancer is the second most common malignancy in men in the world, and radiotherapy is used as a standard treatment modality for this cancer. Although this treatment modality effectively kills prostate cancerous cells, it unavoidably irradiates the organs/tissues that are away from the treatment site. In this regard, radiation-induced testicular toxicities following prostate radiotherapy can affect sexual function, reproduction, and quality of life in cancer survivors. This review summarizes the available data on testicular exposure to radiation during prostate radiotherapy and the consequences on testicular function.

METHODS

To illuminate the radiation-induced testicular toxicities following prostate radiotherapy, a systematic search was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline in PubMed, Web of Science, Scopus, Embase, and clinical trials electronic databases up to September 2018. According to a set of prespecified inclusion and exclusion criteria, 31 eligible articles providing data on testicular function following radiotherapy in patients with prostate cancer were included in the study.

RESULTS

According to the different radiotherapeutic techniques used for prostate cancer treatment, the total tumor dose and scattered testicular dose values were ranging from 36.25 to 78.00 Gy and 0.06 to 6.48 Gy, respectively. Luteinizing hormone and follicle-stimulating hormone levels after prostate radiotherapy were significantly higher in comparison with the pretreatment levels. Around 60% of the studies showed that testosterone levels after prostate radiotherapy were significantly lower than the pretreatment levels. Furthermore, erectile dysfunction (ED), as an adverse side effect resulting from prostate radiotherapy, was reported and this complication is significantly correlated with lower satisfaction with sexual life. Testicular atrophy following prostate radiotherapy has also been observed and its frequency in patients with prior prostate radiotherapy is 2.5 times more than that in the patients without prior radiotherapy.

CONCLUSION

The data revealed that the scattered dose to testicular tissues during prostate radiotherapy can lead to testicular atrophy, variation of the male sex hormones, and quality of sexual life.

Long-Term Endocrine and Metabolic Consequences of Cancer Treatment: A Systematic Review

The number of patients surviving ≥5 years after initial cancer diagnosis has significantly increased during the last decades due to considerable improvements in the treatment of many cancer entities. A negative consequence of this is that the emergence of long-term sequelae and endocrine disorders account for a high proportion of these. These late effects can occur decades after cancer treatment and affect up to 50% of childhood cancer survivors. Multiple predisposing factors for endocrine late effects have been identified, including radiation, sex, and age at the time of diagnosis. A systematic literature search has been conducted using the PubMed database to offer a detailed overview of the spectrum of late endocrine disorders following oncological treatment. Most data are based on late effects of treatment in former childhood cancer patients for whom specific guidelines and recommendations already exist, whereas current knowledge concerning late effects in adult-onset cancer survivors is much less clear. Endocrine sequelae of cancer therapy include functional alterations in hypothalamic-pituitary, thyroid, parathyroid, adrenal, and gonadal regulation as well as bone and metabolic complications. Surgery, radiotherapy, chemotherapy, and immunotherapy all contribute to these sequelae. Following irradiation, endocrine organs such as the thyroid are also at risk for subsequent malignancies. Although diagnosis and management of functional and neoplastic long-term consequences of cancer therapy are comparable to other causes of endocrine disorders, cancer survivors need individually structured follow-up care in specialized surveillance centers to improve care for this rapidly growing group of patients.

Thermoluminescence dosimetry of the dose received by scrotum and testes in radiotherapy of rectal cancer, compared to the point doses calculated by 3D-planning software

PURPOSE

Radiation received by the testes in the course of radiotherapy for rectal cancer may cause oligospermia and azospermia. We sought to determine the dose to the scrotum and testes with thermoluminescence dosimetry (TLD), and compare it to the dose calculated by 3D planning software.

METHODS

The TLDs were fixed to the scrotum in six points anteriorly and posteriorly in two fractions of radiotherapy. All patients received a 50-50.4 Gy total dose in prone position with 3D-planning. The average dose of TLD measurements was compared to the average of 6 relevant point doses calculated by the planning software.

RESULTS

The mean scrotal dose of radiation in 33 patients as measured by TLD was 3.77 Gy (7.5% of the total prescribed dose), and the mean of point doses calculated by the planning software was 4.11 Gy (8.1% of the total dose), with no significant difference. A significant relationship was seen between the position of the inferior edge of the fields and the mean scrotal dose (P = .04). Also body mass index (BMI) was inversely related with the scrotal dose (P = .049).

CONCLUSION

We found a dose of about 4 Gy received by the scrotum and testes from a total prescribed dose of 50 Gy in the radiotherapy of rectal carcinoma patients, with TLD measurements confirming testicular dose estimations by the planning software. This dose could be significantly harmful for spermatogenesis. Thus careful attention to the testicular dose in radiotherapy of rectal cancer for men desiring continued fertility is a necessity.

Process and Pitfalls of Sperm Cryopreservation

Sperm cryopreservation has been utilized routinely for over 40 years to preserve fertility in men undergoing cancer therapy and allow conception for infertile couples. This article provides a concise and up-to-date review of the literature and covers the latest advances in sperm cryopreservation and its array of clinical indications. Over recent years, the scope of clinical indications used for sperm cryopreservation has expanded widely. Consequently, more patient groups are eligible for sperm freezing, requiring specialist resources and higher running costs. Although sperm cryopreservation prior to cancer therapy is readily available in many countries, referral rates by oncology specialists and levels of patient engagement with cryopreservation services are both reported as low. Furthermore, sperm banking continues to raise ethical issues such whether sperm donation should be anonymous and whether sperm can be utilized posthumously by the surviving partner without consent from the patient. This review focuses on the technological advances and ethical controversies in sperm cryopreservation, and how better understanding of these issues could lead to improved access to fertility preserving treatment for patients.

Serum testosterone changes in patients treated with radiation therapy alone for prostate cancer on NRG oncology RTOG 9408

Objectives

We reviewed testosterone changes for patients who were treated with radiation therapy (RT) alone on NRG oncology RTOG 9408.

Methods and materials

Patients (T1b-T2b, prostate-specific antigen <20 ng/mL) were randomized between RT alone and RT plus 4 months of androgen ablation. Serum testosterone (ST) levels were investigated at enrollment, RT completion, and the first follow-up 3 months after RT. The Wilcoxon signed rank test was used to compare pre- and post-treatment ST levels in patients who were randomized to the RT-alone arm.

Results

Of 2028 patients enrolled, 992 patients were randomized to receive RT alone and 917 (92.4%) had baseline ST values available and completed RT. Of these 917 patients, immediate and 3-month post-RT testosterone levels were available for 447 and 373 patients, respectively. Excluding 2 patients who received hormonal therapy off protocol after RT, 447 and 371 patients, respectively, were analyzed. For all patients, the median change in ST values at completion of RT and at 3-month follow-up were −30.0 ng/dL (p5-p95; −270.0 to 162.0; P < .001) and −34.0 ng/dL (p5-p95, −228.0 to 160.0; P < .01), respectively.

Conclusion

RT for prostate cancer was associated with a median 9.2% decline in ST at completion of RT and a median 9.3% decline 3 months after RT. These changes were statistically significant.

Assessment of testicular dose during preoperative radiotherapy for rectal cancer

BACKGROUND

Radiotherapy (RT) for rectal cancer can have adverse effects on testicular function resulting in azoospermia and low testosterone levels. Variability of testicular dose (TD) due to differences in position of testes has been assessed with scrotal dosimeters and resulted in substantial variability of delivered TD. The aim of this study was to estimate planned and delivered TD using a treatment planning system (TPS).

METHODS

In 101 men treated with RT for rectal cancer the cumulative mean TD (mTD) was calculated by TPS based on plan-computed tomography (CT) to evaluate the effect of different predictors on planned TD. The delivered TD was estimated by TPS based on repeated cone-beam CTs in 32 of 101 men to assess within-person variability of planned and delivered TD in a longitudinal analysis.

RESULTS

The median planned mTD for short course RT was 0.57 Gy (range 0.06-14.37 Gy) and 0.81 Gy (range 0.36-10.80 Gy) for long course RT. The median planned mTD was similar to the median delivered mTD in the 32 men analysed over the entire course of RT (p=0.84). The mTD did not change significantly over time of planning and delivering RT. The variation in proximity between testes and planning target volume (PTV) was related to within-person variability of mTD in men on the 50th and 75th percentile of mTD and as expected the absolute difference between planned and delivered mTD increased with higher mTD.

CONCLUSION

Testicular doses calculated based on plan-CT are an accurate estimation of delivered TD based on repeated cone beam (CB)CT. The within-person variability of TD is related to variation in proximity between testes and PTV in men with moderate to high TD.

Acute histopathological responses of testicular tissues after different fractionated abdominal irradiation in rats

PURPOSE

To compare the effects of different fractionated doses of abdominal radiation therapy on acute histopathological responses of testicular tissues in rats.

METHODS

Thirty-three 3-week-old Wistar albino rats were randomized into 6 groups: group 1 (n = 5), control; group 2 (n = 4), hypofractionated total abdominal irradiation (TAI) of 6 Gy/1 fraction/day for 2 days; group 3 (n = 6), hypofractionated TAI of 4 Gy/1 fraction/day for 3 days; group 4 (n = 6), hypofractionated TAI of 3 Gy/1 fraction/day for 4 days; group 5 (n = 6), conventionally fractionated TAI of 2 Gy/1 fraction/day for 6 days; group 6 (n = 6), conventionally fractionated TAI of 1.7 Gy/1 fraction/day for 7 days. Mean epithelial length and diameter of seminiferous tubules of testicular tissues were determined after euthanasia.

RESULTS

Initially, a highly significant decrease in both the mean tubular diameter and epithelial height of the seminiferous tubules was demonstrated in all irradiated rats compared with the control group. No significant differences regarding both damage parameters were found between different hypofractionated radiation therapies. Both conventional radiation therapies reduced the epithelial height and mean diameter of the seminiferous tubules to a lesser extent when compared with 6 Gy/1 fraction/day hypofractionated therapy. It was further shown that parameter values were comparable between rats that received 3 Gy/day hypofractionated therapy and rats that received either of the two conventional therapies. Furthermore, although 4 Gy/day hypofractionation decreased tubular diameter and epithelial length to a greater degree compared with the conventional therapy of 1.7 Gy/1 fraction/day, no statistically significant difference was found when compared with conventional therapy of 2 Gy/1 fraction/day. Additionally, no statistically significant difference was demonstrated between the two types of conventional radiotherapy application.

CONCLUSION

The present study demonstrated that hypofractionated abdominal irradiation leads to more prominent tissue damage in the testes than conventional irradiation.

Sexual dysfunction and infertility as late effects of cancer treatment

Sexual dysfunction is a common consequence of cancer treatment, affecting at least half of men and women treated for pelvic malignancies and over a quarter of people with other types of cancer. Problems are usually linked to damage to nerves, blood vessels, and hormones that underlie normal sexual function. Sexual dysfunction also may be associated with depression, anxiety, relationship conflict, and loss of self-esteem. Innovations in cancer treatment such as robotic surgery or more targeted radiation therapy have not had the anticipated result of reducing sexual dysfunction. Some new and effective cancer treatments, including aromatase inhibitors for breast cancer or chemoradiation for anal cancer also have very severe sexual morbidity. Cancer-related infertility is an issue for younger patients, who comprise a much smaller percentage of total cancer survivors. However, the long-term emotional impact of being unable to have a child after cancer can be extremely distressing. Advances in knowledge about how cancer treatments may damage fertility, as well as newer techniques to preserve fertility, offer hope to patients who have not completed their childbearing at cancer diagnosis. Unfortunately, surveys in industrialised nations confirm that many cancer patients are still not informed about potential changes to their sexual function or fertility, and all modalities of fertility preservation remain underutilised. After cancer treatment, many patients continue to have unmet needs for information about restoring sexual function or becoming a parent. Although more research is needed on optimal clinical practice, current studies suggest a multidisciplinary approach, including both medical and psychosocial treatment options.

Hypofractionated passively scattered proton radiotherapy for low- and intermediate-risk prostate cancer is not associated with post-treatment testosterone suppression

Background.

To investigate post-treatment changes in serum testosterone in low- and intermediate-risk prostate cancer patients treated with hypofractionated passively scattered proton radiotherapy.

Material and methods.

Between April 2008 and October 2011, 228 patients with low- and intermediate-risk prostate cancer were enrolled into an institutional review board-approved prospective protocol. Patients received doses ranging from 70 Cobalt Gray Equivalent (CGE) to 72.5 CGE at 2.5 CGE per fraction using passively scattered protons. Three patients were excluded for receiving androgen deprivation therapy (n = 2) or testosterone supplementation (n = 1) before radiation. Of the remaining 226 patients, pretreatment serum testosterone levels were available for 217. Of these patients, post-treatment serum testosterone levels were available for 207 in the final week of treatment, 165 at the six-month follow-up, and 116 at the 12-month follow-up. The post-treatment testosterone levels were compared with the pretreatment levels using Wilcoxon's signed-rank test for matched pairs.

Results.

The median pretreatment serum testosterone level was 367.7 ng/dl (12.8 nmol/l). The median changes in post-treatment testosterone value were as follows: +3.0 ng/dl (+0.1 nmol/l) at treatment completion; +6.0 ng/dl (+0.2 nmol/l) at six months after treatment; and +5.0 ng/dl (0.2 nmol/l) at 12 months after treatment. None of these changes were statistically significant.

Conclusion.

Patients with low- and intermediate-risk prostate cancer treated with hypofractionated passively scattered proton radiotherapy do not experience testosterone suppression. Our findings are consistent with physical measurements demonstrating that proton radiotherapy is associated with less scatter radiation exposure to tissues beyond the beam paths compared with intensity-modulated photon radiotherapy.

Low incidence of new biochemical and clinical hypogonadism following hypofractionated stereotactic body radiation therapy (SBRT) monotherapy for low- to intermediate-risk prostate cancer

Background

The CyberKnife is an appealing delivery system for hypofractionated stereotactic body radiation therapy (SBRT) because of its ability to deliver highly conformal radiation therapy to moving targets. This conformity is achieved via 100s of non-coplanar radiation beams, which could potentially increase transitory testicular irradiation and result in post-therapy hypogonadism. We report on our early experience with CyberKnife SBRT for low- to intermediate-risk prostate cancer patients and assess the rate of inducing biochemical and clinical hypogonadism.

Methods

Twenty-six patients were treated with hypofractionated SBRT to a dose of 36.25 Gy in 5 fractions. All patients had histologically confirmed low- to intermediate-risk prostate adenocarcinoma (clinical stage ≤ T2b, Gleason score ≤ 7, PSA ≤ 20 ng/ml). PSA and total testosterone levels were obtained pre-treatment, 1 month post-treatment and every 3 months thereafter, for 1 year. Biochemical hypogonadism was defined as a total serum testosterone level below 8 nmol/L. Urinary and gastrointestinal toxicity was assessed using Common Toxicity Criteria v3; quality of life was assessed using the American Urological Association Symptom Score, Sexual Health Inventory for Men and Expanded Prostate Cancer Index Composite questionnaires.

Results

All 26 patients completed the treatment with a median 15 months (range, 13-19 months) follow-up. Median pre-treatment PSA was 5.75 ng/ml (range, 2.3-10.3 ng/ml), and a decrease to a median of 0.7 ng/ml (range, 0.2-1.8 ng/ml) was observed by one year post-treatment. The median pre-treatment total serum testosterone level was 13.81 nmol/L (range, 5.55 - 39.87 nmol/L). Post-treatment testosterone levels slowly decreased with the median value at one year follow-up of 10.53 nmol/L, significantly lower than the pre-treatment value (p < 0.013). The median absolute fall was 3.28 nmol/L and the median percent fall was 23.75%. There was no increase in biochemical hypogonadism at one year post-treatment. Average EPIC sexual and hormonal scores were not significantly changed by one year post-treatment.

Conclusions

Hypofractionated SBRT offers the radiobiological benefit of a large fraction size and is well-tolerated by men with low- to intermediate-risk prostate cancer. Early results are encouraging with an excellent biochemical response. The rate of new biochemical and clinical hypogonadism was low one year after treatment.

Clomiphene citrate and enclomiphene for the treatment of hypogonadal androgen deficiency

Hypogonadism has a number of important clinical consequences related to androgen deficiency and impaired spermatogenesis. The cause of this condition is multifactorial and can result from hypothalamic, pituitary or gonadal dysfunction as well as factors that affect hormonal signaling along the hypothalamic-pituitary-gonadal axis. While testosterone replacement is the most common treatment, it can paradoxically lead to infertility, and may be a less physiologic therapy for patients with secondary hypogonadism due to pituitary dysfunction. Clomiphene citrate, and its derivatives, may allow for restoration of gonadal function by restoring physiologic pituitary function in a subset of patients with hypogonadism.