Safety and tolerability of intermittent androgen deprivation therapy: a literature review

Evaluating the Effects of Prostate Radiotherapy Intensified with Pelvic Nodal Radiotherapy and Androgen Deprivation Therapy on Myelosuppression: Single-Institution Experience

BACKGROUND

Prostate cancer (PCa) management commonly involves the utilization of prostate radiotherapy (PRT), pelvic nodal radiotherapy (PNRT), and androgen deprivation therapy (ADT). However, the potential association of these treatment modalities with bone marrow (BM) suppression remains inadequately reported in the existing literature. This study is designed to comprehensively evaluate the risk of myelosuppression associated with PRT, shedding light on an aspect that has been underrepresented in prior research.

MATERIALS AND METHODS

We conducted a retrospective analysis of 600 patients with prostate cancer (PCa) treated with prostate radiotherapy (PRT) at a single oncology center between 2007 and 2017. Patients were categorized into four cohorts: PRT alone (n = 149), PRT + ADT, (n = 91), PRT + PNRT (n = 39), and PRT + PNRT + ADT (n = 321). To assess the risk of myelosuppression, we scrutinized specific blood parameters, such as hemoglobin (HGB), white blood cells (WBCs), neutrophils (NEUT), lymphocytes (LYM), and platelets (PLT) at baseline, mid-treatment (mRT), immediately post-RT (pRT), 1 month post-RT (1M-pRT), and 1 year post-RT (1Y-pRT). The inter-cohort statistical significance was evaluated with further stratification based on the utilized RT technique {3D conformal radiotherapy (3D-CRT), and intensity-modulated radiation therapy (IMRT)}.

RESULTS

Significant statistical differences at baseline were observed in HGB and LYM values among all cohorts (p < 0.05). Patients in the PRT + PNRT + ADT cohort had significantly lower HGB at baseline and 1M-pRT. In patients undergoing ADT, BMS had a significant impact at 1M-pRT {odds ratio (OR) 9.1; 95% Confidence Interval (CI) 4.8-17.1} and at 1Y-pRT (OR 2.84; CI 1.14-7.08). The use of 3D-CRT was linked to reduced HGB levels in the PRT + PNRT + ADT group at 1 month pRT (p = 0.015). Similarly, PNRT significantly impacted BMS at 1M-pRT (OR 6.7; CI 2.6-17.2). PNRT increased the odds of decreased WBC counts at 1Y-pRT (OR 6.83; CI: 1.02-45.82). Treatment with any RT techniques (3D-CRT or IMRT), particularly in the PRT + PNRT and PRT + PNRT + ADT groups, significantly increased the odds of low LYM counts at all time points except immediately pRT (p < 0.05). Furthermore, NEUT counts were considerably lower at 1M-pRT (p < 0.05) in the PRT + PNRT + ADT group. PLT counts were significantly decreased by PRT + PNRT + ADT at mRT (OR 2.57; 95% CI: 1.42-4.66) but were not significantly impacted by the RT technique.

CONCLUSIONS

Treatment with PRT, ADT, PNRT, and 3D-CRT is associated with BMS. Despite this statistically significant risk, no patient required additional interventions to manage the outcome. While its clinical impact appears limited, its importance cannot be underestimated in the context of increased integration of novel systemic agents with myelosuppressive properties. Longer follow-up should be considered in future studies.

The Use of Androgen Deprivation Therapy for Prostate Cancer Lead to Similar Rate of Following Open Angle Glaucoma: A Population-Based Cohort Study

This study aimed to survey the effect of androgen deprivation therapy (ADT) on the development of open angle glaucoma (OAG) in prostate cancer using the data from national health insurance research database (NHIRD) of Taiwan. A retrospective cohort study was conducted and patients were regarded as prostate cancer with ADT according to related diagnostic, procedure and medication codes. Each prostate subject with ADT was matched to one patient with prostate cancer, but without ADT, and two participants without both prostate cancer and ADT; 1791, 1791 and 3582 patients were recruited in each group. The primary outcome was set as the OAG development according to related diagnostic codes. Cox proportional hazard regression was used to estimate the adjusted hazard ratio (aHR) and 95% confidence interval (CI) of ADT for the incidence of OAG. There were 145, 65 and 42 newly developed OAG cases in the control group, prostate cancer without ADT group and prostate cancer with ADT group. The prostate cancer with ADT group showed a significantly lower risk of OAG development compared to the control group (aHR: 0.689, 95% CI: 0.489-0.972, p = 0.0341), and the risk of OAG development in the prostate cancer without ADT group was similar compared to that in the control group (aHR: 0.825, 95% CI: 0.613-1.111, p = 0.2052). In addition, ages older than 50 years old would lead to higher incidence of OAG development, respectively. In conclusion, the use of ADT will lead to a similar or lower rate of OAG development.

Hematologic Toxicity of Conformal Radiotherapy and Intensity Modulated Radiotherapy in Prostate and Bladder Cancer Patients

Background: The purpose of this study was to compare hematologic adverse effects and hematologic toxicity (HT) of pelvic irradiation in patients treated with conformal radiotherapy (CRT) and intensity modulated radiotherapy (IMRT) for radical treatment of prostate and bladder cancer. Methods: A group of 115 patients with prostate or bladder cancer treated with definitive radical radiotherapy was evaluated retrospectively. Blood test were taken before and after treatment comprising of following indices: white blood cells (WBC) hemoglobin (HGB), red blood cell (RBC), lymphocyte (LC), neutrophil (NC) and platelet (PLT) count. Patients were divided into several subgroups and the data was evaluated statistically using absolute and relative values. Results: There was a statistically significant difference in WBC (p=0.007), NC (p=0.031) and PLT (p=0.026) count decrease (absolute values) after treatment, between two treatment methods (CRT and IMRT), all in favor of IMRT. The relationship still proves to be significant regarding WBC (p=0,02) and (NC) (p=0,049) after presenting the data as relative percentage loss of starting value. However using Common Terminology Criteria for Adverse Effects (CTCAE), PLT count toxicity was more common in IMRT group (p=0.045). Conclusion: IMRT in comparison to CRT in bladder and prostate cancer patients is associated with a lesser absolute and relative decrease of hematologic indices. The hematologic effect of radiation was observed mainly regarding LC. Patients treated with IMRT suffered from significantly lesser decrease in relative and absolute values of WBC and NC. The mean of absolute PLT decrease count was lower in IMRT group; however, toxicity according to CTCAE was slightly more prevalent in IMRT group.

Effective chemotherapy of heterogeneous and drug-resistant early colon cancers by intermittent dose schedules: a computer simulation study

PURPOSE

The effectiveness of cancer chemotherapy is limited by intra-tumor heterogeneity, the emergence of spontaneous and induced drug-resistant mutant subclones, and the maximum dose to which normal tissues can be exposed without adverse side effects. The goal of this project was to determine if intermittent schedules of the maximum dose that allows colon crypt maintenance could overcome these limitations, specifically by eliminating mixtures of drug-resistant mutants from heterogeneous early colon adenomas while maintaining colon crypt function.

METHODS

A computer model of cell dynamics in human colon crypts was calibrated with measurements of human biopsy specimens. The model allowed simulation of continuous and intermittent dose schedules of a cytotoxic chemotherapeutic drug, as well as the drug's effect on the elimination of mutant cells and the maintenance of crypt function.

RESULTS

Colon crypts can tolerate a tenfold greater intermittent dose than constant dose. This allows elimination of a mixture of relatively drug-sensitive and drug-resistant mutant subclones from heterogeneous colon crypts. Mutants can be eliminated whether they arise spontaneously or are induced by the cytotoxic drug.

CONCLUSIONS

An intermittent dose, at the maximum that allows colon crypt maintenance, can be effective in eliminating a heterogeneous mixture of mutant subclones before they fill the crypt and form an adenoma.

Cognitive impairment among prostate cancer patients: An overview of reviews

To identify and clarify definitions and methods of measuring cancer-related cognitive impairment among prostate cancer patients treated with androgen deprivation therapy (ADT) and to assess the incidence and prevalence of cognitive impairment. A systematic review of Medline, EMBASE, PubMed, PsycINFO and CINAHL up to December 2015 was undertaken to identify English-language reviews. A total of 28 reviews were identified describing 20 primary studies. There were no studies of incidence. Reported prevalence rates varied between 10% and 69%. Cognitive domains impaired by ADT included: verbal memory, visuospatial ability and executive functions. Cognitive impairment was infrequently defined and four definitions were reported. A variety of measures and methods were used to assess cognitive function including neuropsychological tests, self-report measures and clinical assessments. The finding that, often, one measure was used to assess more than one aspect of cognition is likely to have contributed to imprecise estimates. There is a need to agree a definition of cognitive impairment in the clinical epidemiology of cancer and to standardise the selection of measures in order to aid accurate assessment and fair comparisons across studies regarding the prevalence of cognitive impairment among prostate cancer patients.

Integrating diet and exercise into care of prostate cancer patients on androgen deprivation therapy

Improved diagnosis and treatment regimens have resulted in greater longevity for men with prostate cancer. This has led to an increase in both androgen deprivation therapy (ADT) use and duration of exposure, and therefore to its associated adverse effects, such as sexual dysfunction, osteoporosis, reduced muscle mass, increased fat mass, and increased incidence of cardiovascular disease and type 2 diabetes. Given that the adverse effects of ADT are systemic, often debilitating, and difficult to treat, efforts continue in the development of new strategies for long-term management of prostate cancer. The PubMed database was searched to select trials, reviews, and meta-analyses in English using such search terms as "prostate cancer" and "androgen deprivation therapy", "cardiovascular risk", "lean body mass", "exercise", and "diet". The initial searches produced 379 articles with dates 2005 or more recent. Articles published after 2004 were favored. This review utilizes the latest data to provide a status update on the effects of exercise and diet on patients with prostate cancer, focusing on ADT-associated side effects, and it discusses the evidence for such interventions. Since the evidence of large-scale trials in patients with prostate cancer is missing, and an extrapolation of supporting data to all patient subgroups cannot be provided, individualized risk assessments remain necessary before the initiation of exercise and diet programs. Exercise, diet, and nutritional supplementation interventions have the potential to provide effective, accessible, and relatively inexpensive strategies for mitigating ADT-associated toxicities without introducing additional adverse effects.

Evaluating Intermittent Androgen-Deprivation Therapy Phase III Clinical Trials: The Devil Is in the Details

PURPOSE

Intermittent androgen deprivation (IAD) has been widely tested in prostate cancer. However, phase III trials testing continuous androgen deprivation (CAD) versus IAD have reached inconclusive and seemingly contradictory results. Different design and conduct issues must be critically evaluated to better interpret the results.

PATIENTS AND METHODS

Seven published phase III trials were examined for prespecified design and outcomes. Treatment specifications; primary end point; superiority versus noninferiority design assumptions, including magnitude of assumed versus observed noninferiority margin (NIM); duration of follow-up; and quality-of-life (QOL) outcomes were considered in terms of the results and conclusions reported.

RESULTS

Five trials had a superiority and three had a noninferiority primary hypothesis. Only three trials had a uniform population and overall survival (OS) end point. All trials observed better outcomes in terms of OS and progression-free survival (PFS) than assumed at time of study design, translating into prespecified NIMs or hazard ratios that reflected larger absolute differences in OS or PFS between arms. Lower-than-expected event rates also reduced statistical power for the trials. Other factors, including length of follow-up, cause of death, QOL, and primary end point, and their impact on trial interpretation are discussed.

CONCLUSION

No trial to date has demonstrated survival superiority of IAD compared with CAD. Trials concluding IAD is noninferior to CAD were based on wide NIMs that included clinically important survival differences, not likely to be considered comparable by physicians or patients. Interim analyses relying on short follow-up and including a majority of non-prostate cancer deaths will favor a noninferiority conclusion and should be interpreted cautiously. Adequate follow-up is required to ensure capture of prostate cancer deaths in both superiority and noninferiority trials.

Quantifying the evidence for the risk of metabolic syndrome and its components following androgen deprivation therapy for prostate cancer: a meta-analysis

Background

No meta-analysis is yet available for the risk of metabolic syndrome (MetS) following androgen deprivation therapy (ADT) for men with prostate cancer. To summarize the evidence for the link between ADT and MetS or its components quantitatively with a meta-analysis including all studies published to date.

Methods

PubMed and Embase were searched using predefined inclusion criteria to perform meta-analyses on the association between metabolic syndrome, hyperglycemia, diabetes, hypertension, dyslipidemia or obesity and androgen deprivation therapy in patients with prostate cancer. Random effects methods were used to estimate pooled relative risks (RRs) and 95% confidence intervals (CI).

Results

A total of nine studies was included. There was a positive association between ADT and risk of MetS (RR: 1.75 (95% CI: 1.27–2.41)). Diabetes was the only MetS component present in more than 3 studies, and also showed an increased risk following ADT (RR: 1.36 (95% CI: 1.17–1.58)).

Conclusion

This is the first quantitative summary addressing the potential risk of MetS following ADT in men with PCa. The positive RRs indicate that there is a need to further elucidate how type and duration of ADT affect these increased risks of MetS and diabetes as the number of men with PCa treated with ADT is increasing.

A review of continuous vs intermittent androgen deprivation therapy: redefining the gold standard in the treatment of advanced prostate cancer. Myths, facts and new data on a ″perpetual dispute″

OBJECTIVES

To review the literature and present new data of continuous androgen deprivation therapy (ADT) vs intermittent androgen deprivation (IAD) as therapies for prostate cancer in terms of survival and quality of life and clarify practical issues in the use of IAD.

MATERIALS AND METHODS

We conducted a systematic search on Medline and Embase databases using ″prostatic neoplasm″ and ″intermittent androgen deprivation″ as search terms. We reviewed meta-analyses, randomised controlled trials, reviews, clinical trials and practise guidelines written in English from 2000 and onwards until 01/04/2013. Ten randomized controlled trials were identified. Seven of them published extensive data and results randomizing 4675 patients to IAD versus CAD. Data from the other three randomized trials were limited.

RESULTS

Over the last years studies confirmed that IAD is an effective alternative approach to hormonal deprivation providing simultaneously several potential benefits in terms of quality of life and cost effectiveness. Thus, in patients with non metastatic, advanced prostate cancer IAD could be used as standard treatment, while in metastatic prostate cancer IAD role still remains ambiguous.

CONCLUSIONS

Nowadays, revaluation of the gold standard of ADT in advanced prostate cancer appears essential. Recent data established that IAD should no longer be consi¬dered as investigational, since its effectiveness has been proven, especially in patients suffering from non-metastatic advanced prostate cancer.

Intermittent versus continuous androgen deprivation for locally advanced, recurrent or metastatic prostate cancer: a systematic review and meta-analysis

BACKGROUND

Prostate cancer is the most common cancer in older men in the United States (USA) and Western Europe. Androgen deprivation (AD) constitutes, in most cases, the first-line of treatment for these cases. The negative impact of CAD in quality of life, secondary to the adverse events of sustained hormone deprivation, plus the costs of this therapy, motivated the intermittent treatment approach. The objective of this study is to to perform a systematic review and meta-analysis of all randomized controlled trials that compared the efficacy and adverse events profile of intermittent versus continuous androgen deprivation for locally advanced, recurrent or metastatic hormone-sensitive prostate cancer.

METHODS

Several databases were searched, including MEDLINE, EMBASE, LILACS, and CENTRAL. The endpoints were overall survival (OS), cancer-specific survival (CSS), time to progression (TTP) and adverse events. We performed a meta-analysis (MA) of the published data. The results were expressed as Hazard Ratio (HR) or Risk Ratio (RR), with their corresponding 95% Confidence Intervals (CI 95%).

RESULTS

The final analysis included 13 trials comprising 6,419 patients with hormone-sensitive prostate cancer. TTP was similar in patients who received intermittent androgen deprivation (IAD) or continuous androgen deprivation (CAD) (fixed effect: HR = 1.04; CI 95% = 0.96 to 1.14; p = 0.3). OS and CSS were also similar in patients treated with IAD or CAD (OS: fixed effect: HR = 1.02; CI 95% = 0.95 to 1.09; p = 0.56 and CSS: fixed effect: HR = 1.06; CI 95% = 0.96 to 1.18; p = 0.26).

CONCLUSION

Overall survival was similar between IAD and CAD in patients with locally advanced, recurrent or metastatic hormone-sensitive prostate cancer. Data on CSS are weak and the benefits of IAD on this outcome remain uncertain. Impact in QoL was similar for both groups, however, sexual activity scores were higher and the incidence of hot flushes was lower in patients treated with IAD.

Androgen receptor in human prostate cancer-associated fibroblasts promotes prostate cancer epithelial cell growth and invasion

The androgens and androgen receptor (AR) play key roles in the prostate cancer (PCa) development and progression via epithelium-stroma cross talk. Prostate cancer-associated fibroblasts (CAFs) are dominant components in PCa stroma and are essential in the malignant progression by supporting tumorigenesis and metastasis. However, the AR roles in CAFs are still obscure. We isolated and immortalized the CAFs from human PCa tissues and found the CAFs are AR positive. We then knocked down their AR with siRNA and co-cultured the resultant CAFs with PCa cell line PC3. The MTT, invasion, and colony formation assays were performed to study the PC3 biological behavior. The results showed that the PCa epithelial growth, invasion, and colony formation abilities decreased when knocking down the CAFs AR. By using the real-time quantitative polymerase chain reaction, we found the IGF1, FGF7, FGF10, SDF1, HGF, and TGFb2 expression levels decreased in the AR knocked down CAFs. These results suggested that the AR in CAFs promoted PCa epithelial growth and invasion via regulating a series of growth factors. Targeting the AR in CAFs might be a potential therapeutic option for PCa in future.

Six-month leuprorelin acetate depot formulations in advanced prostate cancer: a clinical evaluation

For nearly three decades, gonadotropin-releasing hormone (GnRH) agonists, particularly leuprorelin acetate (LA), have served as an important part of the treatment armamentarium for prostate cancer. The introduction of LA depot formulations provided a significant improvement in the acceptance of this therapy; however, their indicated treatment duration of 1 to 4 months was still not long enough to satisfy all medical needs. For this reason some manufacturers developed new injectable formulations that provide testosterone suppression for 6 months. This review article assesses key publications in order to compare these long-acting, commercially available, LA depot formulations and their clinical performance. The literature search identified 14 publications; by excluding reviews, duplications, and non-English articles, only three original papers describing clinical trial remained for review: two focused on microsphere-based LA formulations with either a 30 mg or 45 mg dose and one focused on a gel-based leuprorelin acetate with a 45 mg dose. All products were tested in individual clinical trials and have demonstrated their efficacy and safety.

Intermittent androgen-deprivation therapy in prostate cancer: a critical review focused on phase 3 trials

CONTEXT

Intermittent androgen deprivation (IAD) in prostate cancer (PCa) patients has been proposed to delay development of castration resistance and to reduce the side effects and costs of androgen deprivation therapy (ADT).

OBJECTIVE

This review analyzes (1) the oncologic and quality of life (QoL) results from randomized phase 3 trials comparing IAD and continuous ADT and (2) the prognostic parameters for IAD.

EVIDENCE ACQUISITION

We searched the Medline and Cochrane Library databases (primary fields: prostate neoplasm and intermittent androgen deprivation; secondary fields: randomized trials, survival, quality of life, predictors) without language restriction.

EVIDENCE SYNTHESIS

We found seven extensively described phase 3 trials randomizing 4675 patients to IAD versus continuous ADT. Other randomized trials investigating IAD have been performed, but available data are limited and have been published only in preliminary fashion. In all seven trials, patients spent most of their time on, rather than off, ADT. The induction periods ranged from 3 mo to 8 mo; in all but one trial, the PSA level designated for ADT discontinuation was <4 ng/ml. Mean follow-up ranged from 40-108 mo. Collectively, these trials support the concept that, mainly in metastatic cases, IAD can produce oncologic results similar to continuous ADT. In terms of overall survival, the hazard ratios for IAD and continuous ADT were very similar (range: 0.98-1.08). The QoL benefit of IAD appears to be modest at best. With IAD, QoL is likely influenced by the duration of the off-treatment periods and by the rate of testosterone recovery.

CONCLUSIONS

The evidence indicates that IAD is not inferior to continuous ADT. Data are insufficient to determine whether IAD is able to prevent the long-term complications of ADT. More comparative analysis focused on QoL is warranted.

Intermittent versus continuous androgen deprivation in prostate cancer

BACKGROUND

Castration resistance occurs in most patients with metastatic hormone-sensitive prostate cancer who are receiving androgen-deprivation therapy. Replacing androgens before progression of the disease is hypothesized to prolong androgen dependence.

METHODS

Men with newly diagnosed, metastatic, hormone-sensitive prostate cancer, a performance status of 0 to 2, and a prostate-specific antigen (PSA) level of 5 ng per milliliter or higher received a luteinizing hormone-releasing hormone analogue and an antiandrogen agent for 7 months. We then randomly assigned patients in whom the PSA level fell to 4 ng per milliliter or lower to continuous or intermittent androgen deprivation, with patients stratified according to prior or no prior hormonal therapy, performance status, and extent of disease (minimal or extensive). The coprimary objectives were to assess whether intermittent therapy was noninferior to continuous therapy with respect to survival, with a one-sided test with an upper boundary of the hazard ratio of 1.20, and whether quality of life differed between the groups 3 months after randomization.

RESULTS

A total of 3040 patients were enrolled, of whom 1535 were included in the analysis: 765 randomly assigned to continuous androgen deprivation and 770 assigned to intermittent androgen deprivation. The median follow-up period was 9.8 years. Median survival was 5.8 years in the continuous-therapy group and 5.1 years in the intermittent-therapy group (hazard ratio for death with intermittent therapy, 1.10; 90% confidence interval, 0.99 to 1.23). Intermittent therapy was associated with better erectile function and mental health (P<0.001 and P=0.003, respectively) at month 3 but not thereafter. There were no significant differences between the groups in the number of treatment-related high-grade adverse events.

CONCLUSIONS

Our findings were statistically inconclusive. In patients with metastatic hormone-sensitive prostate cancer, the confidence interval for survival exceeded the upper boundary for noninferiority, suggesting that we cannot rule out a 20% greater risk of death with intermittent therapy than with continuous therapy, but too few events occurred to rule out significant inferiority of intermittent therapy. Intermittent therapy resulted in small improvements in quality of life. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT00002651.).

Androgen deprivation therapy: evidence-based management of side effects

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: The benefits of androgen deprivation therapy (ADT) are well recognized and a multitude of studies have documented the benefits of ADT in conjunction with other therapies. Given the widespread use of ADT due to its important clinical implications, it is imperative that clinicians understand the side effects to limit treatment-related morbidity. There are numerous well recognized adverse effects of ADT, including vasomotor flushing, loss of libido and impotence, fatigue, gynaecomastia, anaemia, osteoporosis and metabolic complications, as well as effects on cardiovascular health and bone density. Present study focuses on the most recent evidence-based treatment options for various side effects of ADT.

OBJECTIVE

To familiarize clinicians with the various side effects of androgen deprivation therapy (ADT). The present study focuses on the most recent evidence-based treatment strategies for the common side effects of ADT.

METHODS

A PubMed database search was conducted from 2000 to 2012. All prospective clinical studies were selected, including randomized and non-randomized clinical trials, as well as meta-analysis studies concerning preventive and therapeutic interventions for various side effects of ADT. 'The Oxford 2011 Levels of Evidence' classification system for treatment benefits was used to categorize selected studies.

RESULTS

Gabapentin shows moderate efficacy for the long-term treatment of hot flashes in a dose-dependent manner. A combined resistance/aerobic exercise programme leads to significant improvement in fatigue, sexual function and cognitive function. A home-based/group exercise programme also improves fatigue and unfavourable metabolic changes. Denosumab increases lumbar spine, hip and radius bone mass density, and also reduces the risk of vertebral fractures in men receiving ADT for non-metastatic prostate cancer. Metformin coupled with lifestyle intervention is a safe, well-tolerated intervention for adverse metabolic changes. Toremifene improves the lipid profile. Intermittent ADT improves early side effects, such as hot flashes, sexual activity, fatigue, and quality of life, although its effect on long-term side effects remains inconclusive.

CONCLUSION

Despite significant improvement in management strategies for the side effects of ADT, the best way of preventing side effects is to use ADT only when it is absolutely indicated.