Use of sildenafil or other phosphodiesterase inhibitors and risk of melanoma

The relationship between the history of PDE5-inhibitors assumption and melanoma: a systematic review

INTRODUCTION

Phosphodiesterase 5 inhibitors (PDE5-is) are used worldwide as first line therapy for erectile dysfunction (ED). Current literature reported data on the warning association between PDE5-is use and the development of cutaneous melanoma. However, these data are contrasting, thus we aim to summarise evidence regarding this association.

CONTENT

A systematic review of all published articles related to the effects of PDE5-is in the development of cutaneous melanoma was performed. PubMed, EMBASE, and Cochrane library were queried for all the published studies indexed up to the 26th of May 2023. A combination of keywords related to PDE5-is and melanoma were used. Only original studies based on human subjects in the English language were included in the analysis.

SUMMARY AND OUTLOOK

Of 505 articles identified, only eight original articles were considered for further analysis. Overall, five of the selected articles including 657,984 subjects agrees on an increased risk of developing melanoma in PDE5-is users. On the other hand, three original articles based on data regarding 360,915 subjects, disagree with the previous statement declaring any association between PDE5-i use and melanoma. Current literature still reports contrasting data regarding the association between PDE5-is assumption and increased risk of melanoma, but a possible association is described, bringing attention to higher risk melanoma category of patients. More clinical studies are needed to clarify the impact of PDE5-is in the development and progression of melanoma.

Advancements in Phosphodiesterase 5 Inhibitors: Unveiling Present and Future Perspectives

Phosphodiesterase 5 (PDE5) inhibitors presented themselves as important players in the nitric oxide/cGMP pathway, thus exerting a profound impact on various physiological and pathological processes. Beyond their well-known efficacy in treating male erectile dysfunction (ED) and pulmonary arterial hypertension (PAH), a plethora of studies have unveiled their significance in the treatment of a myriad of other diseases, including cognitive functions, heart failure, multiple drug resistance in cancer therapy, immune diseases, systemic sclerosis and others. This comprehensive review aims to provide an updated assessment of the crucial role played by PDE5 inhibitors (PDE5-Is) as disease-modifying agents taking their limiting side effects into consideration. From a medicinal chemistry and drug discovery perspective, the published PDE5-Is over the last 10 years and their binding characteristics are systemically discussed, and advancement in properties is exposed. A persistent challenge encountered with these agents lies in their limited isozyme selectivity; considering this obstacle, this review also highlights the breakthrough development of the recently reported PDE5 allosteric inhibitors, which exhibit an unparalleled level of selectivity that was rarely achievable by competitive inhibitors. The implications and potential impact of these novel allosteric inhibitors are meticulously explored. Additionally, the concept of multi-targeted ligands is critically evaluated in relation to PDE5-Is by inspecting the broader spectrum of their molecular interactions and effects. The objective of this review is to provide insight into the design of potent, selective PDE5-Is and an overview of their biological function, limitations, challenges, therapeutic potentials, undergoing clinical trials, future prospects and emerging uses, thus guiding upcoming endeavors in both academia and industry within this domain.

Tranexamic acid use is not associated with the risk of melanoma in Danish women: A nested case-control study using Danish health registries

BACKGROUND

Repurposing already approved drugs in a cancer setting has gained increasing interest in recent years. Tranexamic acid is an anti-fibrinolytic drug that has recently been suggested as an anti-cancer drug due to its anti-inflammatory and anti-carcinogenic effects in animal studies. In this study, we aimed to investigate the possible melanoma-preventive role of tranexamic acid in Danish women.

METHOD

In this nested case-control study, we identified female cases 18-60 years with first-time melanoma during 2000-2015 and age-matched them with 10 female controls. The odds ratio (OR) of melanoma with tranexamic acid ever- or high use (≥ 100,000 mg) was estimated using conditional logistic regression.

RESULTS

A total of 7986 women with incident melanoma were eligible for study inclusion and were matched to 79,860 controls. Most exposed cases and controls were exposed to low cumulative doses of tranexamic acid corresponding to around 5 days of continuous treatment (1000 mg 3 times daily) for the presumed main indication, i.e., menorrhagia. The crude OR associating tranexamic ever use with melanoma was 1.04 (95% CI 0.98-1.11, p = 0.20), and the adjusted OR was 1.03 (0.97-1.10, p = 0.32). We found no dose-response pattern or effect measure modification by age, histologic type, localization, or clinical stage. However, prolonged use with cumulative doses of tranexamic acid (≥ 100,000 mg) was associated with an increased risk of melanoma (adjusted OR 1.23,95 %, CI 0.96-1.56), compared with non-use.

CONCLUSION

We found no association between tranexamic acid use and the risk of melanoma in Danish women. This could be explained by underlying dose- or biological factors, and sporadic use patterns. A higher risk of melanoma was seen among prolonged users which could be due to surveillance bias.

Beyond Erectile Dysfunction: cGMP-Specific Phosphodiesterase 5 Inhibitors for Other Clinical Disorders

Cyclic guanosine monophosphate (cGMP), an important intracellular second messenger, mediates cellular functional responses in all vital organs. Phosphodiesterase 5 (PDE5) is one of the 11 members of the cyclic nucleotide phosphodiesterase (PDE) family that specifically targets cGMP generated by nitric oxide-driven activation of the soluble guanylyl cyclase. PDE5 inhibitors, including sildenafil and tadalafil, are widely used for the treatment of erectile dysfunction, pulmonary arterial hypertension, and certain urological disorders. Preclinical studies have shown promising effects of PDE5 inhibitors in the treatment of myocardial infarction, cardiac hypertrophy, heart failure, cancer and anticancer-drug-associated cardiotoxicity, diabetes, Duchenne muscular dystrophy, Alzheimer's disease, and other aging-related conditions. Many clinical trials with PDE5 inhibitors have focused on the potential cardiovascular, anticancer, and neurological benefits. In this review, we provide an overview of the current state of knowledge on PDE5 inhibitors and their potential therapeutic indications for various clinical disorders beyond erectile dysfunction.

Use of phosphodiesterase-5 inhibitors and the incidence of melanoma

INTRODUCTION

Recent evidence of a causal link between Phosphodiesterase-5-inhibitor (PDE-5i) use and melanoma has caused concern in PDE-5i use and was even addressed in the 2018 American Urological Association guideline on erectile dysfunction (ED). Given that several studies have affirmed this low probability but statistically significant association, one might expect a shift in melanoma diagnoses since PDE-5is were introduced in 1998. We sought to determine if the introduction of PDE-5i drugs for ED treatment increased incidence of melanoma.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was used to compare the incidence of melanoma diagnosis in American men between 1973 and 2015, providing over a decade of data before and after PDE-5i introduction in 1998. Interrupted time-series and logistic regression were used to assess this relationship.

RESULTS

Over 43 years, the SEER database has reported 292,166 cases of Melanoma, with males accounting for 53.7% of cases (Standard deviation [SD] 3%, Range 47.5-58.3%). After the introduction of PDE-5i, there was no proportional increase in melanoma diagnoses, in fact demonstrating a 2% lower incidence from prediction models (p < 0.05).

CONCLUSION

Our analysis of the SEER database demonstrates that the trend in incidence of melanoma has fallen in the era of PDE-5i use for ED. These findings may be of value in counseling patients anxious about the potential association between PDE-5i use and skin cancer; however, continued research analyzing individual-level risk are needed.

Phosphodiesterase Type 5 Inhibitors and Risk of Skin Cancers in Men: A Meta-Analysis and Trial Sequential Analysis Involving 7,479,852 Subjects

Purpose

We conducted a systematic review and meta-analysis to quantify the association between phosphodiesterase type 5 inhibitors (PDE5Is) use and skin cancers and we also examined whether down-expression of the PDE5A gene was related to worse prognosis for malignant melanoma (MM) patients.

Materials and Methods

The PubMed, Cochrane Library, Web of Science, EMBASE, and ClinicalTrails.gov databases were searched. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the association between PDE5Is use and risk of skin cancers. Cumulative meta-analysis and trial sequential analysis (TSA) were also conducted. Survival outcomes were analyzed online.

Results

After pooling all 8 eligible studies comprising 7,479,852 subjects, we found that PDE5Is use was significantly associated with slightly increased risk of developing MM (OR: 1.13, 95% CI: 1.05 to 1.21, I²=67.1%), basal cell carcinoma (OR: 1.16, 95% CI: 1.13 to 1.19, I²=49.6%), and squamous cell carcinoma (OR: 1.07, 95% CI: 1.01 to 1.13, I²=0.0%). Totally, PDE5Is increased the risk of developing skin cancers (OR: 1.13, 95% CI: 1.09 to 1.17, I²=70.8%). TSA results showed that the sample size was enough to reach a positive conclusion.

Conclusions

The use of PDE5Is may be slightly associated with increased risk of developing skin cancers. There should be a balance between drug benefits and potential safety issues. However, the pooled results should be considered tentative until confounding factors such as sun exposure and lifestyle are well-controlled in further studies.

Discovery of Novel Agents on Spindle Assembly Checkpoint to Sensitize Vinorelbine-Induced Mitotic Cell Death Against Human Non-Small Cell Lung Cancers

Non-small cell lung cancer (NSCLC) accounts about 80% of all lung cancers. More than two-thirds of NSCLC patients have inoperable, locally advanced or metastatic tumors. Non-toxic agents that synergistically potentiate cancer-killing activities of chemotherapeutic drugs are in high demand. YL-9 was a novel and non-cytotoxic compound with the structure related to sildenafil but showing much less activity against phosphodiesterase type 5 (PDE5). NCI-H460, an NSCLC cell line with low PDE5 expression, was used as the cell model. YL-9 synergistically potentiated vinorelbine-induced anti-proliferative and apoptotic effects in NCI-H460 cells. Vinorelbine induced tubulin acetylation and Bub1-related kinase (BUBR1) phosphorylation, a necessary component in spindle assembly checkpoint. These effects, as well as BUBR1 cleavage, were substantially enhanced in co-treatment with YL-9. Several mitotic arrest signals were enhanced under combinatory treatment of vinorelbine and YL-9, including an increase of mitotic spindle abnormalities, increased cyclin B1 expression, B-cell lymphoma 2 (Bcl-2) phosphorylation and increased phosphoproteins. Moreover, YL-9 also displayed synergistic activity in combining with vinorelbine to induce apoptosis in A549 cells which express PDE5. In conclusion. the data suggest that YL-9 is a novel agent that synergistically amplifies vinorelbine-induced NSCLC apoptosis through activation of spindle assembly checkpoint and increased mitotic arrest of the cell cycle. YL-9 shows the potential for further development in combinatory treatment against NSCLC.

Development of novel phosphodiesterase 5 inhibitors for the therapy of Alzheimer's disease

Nitric oxide (NO) is a gaseous molecule that plays a multifactorial role in several cellular processes. In the central nervous system, the NO dual nature in neuroprotection and neurotoxicity has been explored to unveil its involvement in Alzheimer's disease (AD). A growing body of research shows that the activation of the NO signaling pathway leading to the phosphorylation of the transcription factor cyclic adenine monophosphate responsive element binding protein (CREB) (so-called NO/cGMP/PKG/CREB signaling pathway) ameliorates altered neuroplasticity and memory deficits in AD animal models. In addition to NO donors, several other pharmacological agents, such as phosphodiesterase 5 (PDE5) inhibitors have been used to activate the pathway and rescue memory disorders. PDE5 inhibitors, including sildenafil, tadalafil and vardenafil, are marketed for the treatment of erectile dysfunction and arterial pulmonary hypertension due to their vasodilatory properties. The ability of PDE5 inhibitors to interfere with the NO/cGMP/PKG/CREB signaling pathway by increasing the levels of cGMP has prompted the hypothesis that PDE5 inhibition might be used as an effective therapeutic strategy for the treatment of AD. To this end, newly designed PDE5 inhibitors belonging to different chemical classes with improved pharmacologic profile (e.g. higher potency, improved selectivity, and blood-brain barrier penetration) have been synthesized and evaluated in several animal models of AD. In addition, recent medicinal chemistry effort has led to the development of agents concurrently acting on the PDE5 enzyme and a second target involved in AD. Both marketed and investigational PDE5 inhibitors have shown to reverse cognitive defects in young and aged wild type mice as well as transgenic mouse models of AD and tauopathy using a variety of behavioral tasks. These studies confirmed the therapeutic potential of PDE5 inhibitors as cognitive enhancers. However, clinical studies assessing cognitive functions using marketed PDE5 inhibitors have not been conclusive. Drug discovery efforts by our group and others are currently directed towards the development of novel PDE5 inhibitors tailored to AD with improved pharmacodynamic and pharmacokinetic properties. In summary, the present perspective reports an overview of the correlation between the NO signaling and AD, as well as an outline of the PDE5 inhibitors used as an alternative approach in altering the NO pathway leading to an improvement of learning and memory. The last two sections describe the preclinical and clinical evaluation of PDE5 inhibitors for the treatment of AD, providing a comprehensive analysis of the current status of the AD drug discovery efforts involving PDE5 as a new therapeutic target.

Erectile Dysfunction Medications and Skin Cancer: An Analysis in US Veterans

OBJECTIVE

To examine the relationship between phosphodiesterase 5 inhibitor drugs (PDE5i) and skin cancers in a large-scale study of Veterans.

METHODS

This was a retrospective database review using the Department of Veterans Affairs Informatics and Computing Infrastructure database. Veterans Affairs Informatics and Computing Infrastructure was searched 19 years for Veterans who received PDE5i treatment of erectile dysfunction. A non-PDE5i group of Veterans was selected for comparison analysis. Follow-up time, outpatient clinic visits and incidence of malignant melanoma (MM), and basal cell carcinoma (BCC) were measured in both groups.

RESULTS

A total of 2.55 million Veterans were included in this study (1.27 million in each group). Mean age of the PDE5i group and non-PDE5i group was 59.2 years (standard deviation [SD] ± 10.8) and 58.7 (SD ± 10.8), respectively. Mean follow-up time for the PDE5i group was 8.9 years (SD ± 4.2) and 8.5 years (SD ± 4.3) for non-PDE5i group. Odds ratio for malignant melanoma and BCC in the PDE5i group was 1.25 (confidence interval 95%, 1.22-1.28, P <.0001) and 1.49 (confidence interval 95%, 1.46-1.51, P <.0001), respectively. PDE5i users showed more mean outpatient visits/year (8.9 SD ± 9.50) compared to non-PDE5i users (5.9 SD ± 10.0; P <.0001).

CONCLUSION

Veterans prescribed PDE5is to treat erectile show a minimal increased risk of MM and a greater risk of BCC compared to non-PDE5i users. PDE5i users visited outpatient VA clinics at a higher rate than non-PDE5i users in this study. These findings suggest confounding variables are likely involved in the relationship between skin cancers and PDE5i use. PDE5i drugs remain a safe treatment for erectile dysfunction.

Phosphodiesterase inhibitors for lower urinary tract symptoms consistent with benign prostatic hyperplasia

BACKGROUND

Benign prostatic hyperplasia (BPH) refers to non-malignant enlargement of the prostate gland that may cause bothersome lower urinary tract symptoms (LUTS). Alpha-blockers (ABs) and 5-alpha reductase inhibitors (5-ARIs) are the mainstay of medical treatment. Recently, phosphodiesterase inhibitors (PDEIs) that so far have been used mainly to treat erectile dysfunction were introduced to treat male LUTS.

OBJECTIVES

To assess the effects of PDEIs compared to placebo and other standard of care drugs (ABs and 5-ARIs) in men with LUTS consistent with BPH.

SEARCH METHODS

We conducted a systematic search of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Web of Science, and clinical trials registries of the World Health Organization (WHO) and the National Institutes of Health (NIH) (updated 2 August 2018). We performed citation tracking and handsearching of abstracts and conference proceedings. We also contacted study authors to ask for additional information.

SELECTION CRITERIA

We considered for inclusion in this systematic review randomised controlled trials (RCTs) comparing PDEIs versus placebo, ABs, or 5-ARIs for at least four weeks in men with BPH-LUTS.

DATA COLLECTION AND ANALYSIS

Three review authors independently screened the literature and extracted data. Primary outcomes were effects on urinary symptoms as assessed by the International Prostate Symptom Score (IPSS-total; score ranging from 0 to 35, with higher values reflecting more symptoms), urinary bother as assessed by the Benign Prostatic Hyperplasia Impact Index (BPHII; score ranging from 0 to 13, with higher values reflecting more bother), and adverse events (AEs). We used GRADE to rate the quality of evidence. We considered short-term (up to 12 weeks) and long-term (12 weeks or longer) results separately.

MAIN RESULTS

We included a total of 16 randomised trials in this review. The results for primary outcomes are as follows.PDEI versus placebo: PDEIs may result in a small improvement in IPSS-total score (mean difference (MD) 1.89 lower, 95% confidence interval (CI) 2.27 lower to 1.50 lower; n = 4293; low-quality evidence) compared to placebo, and may reduce the BPHII score slightly (MD 0.52 lower, 95% CI 0.71 lower to 0.33 lower; n = 3646; low-quality evidence). Rates of AEs may be increased (risk ratio (RR) 1.42, 95% CI 1.21 to 1.67; n = 4386; low-quality evidence). This corresponds to 95 more AEs per 1000 participants (95% CI 47 more to 151 more per 1000). Study results were limited to a treatment duration of six to 12 weeks.PDEI versus AB: PDEIs and ABs probably provide similar improvement in IPSS-total score (MD 0.22 higher, 95% CI 0.49 lower to 0.93 higher; n = 933; moderate-quality evidence) and may have a similar effect on BPHII score (MD 0.03 higher, 95% CI 1.10 lower to 1.16 higher; n = 550; low-quality evidence) and AEs (RR 1.35, 95% CI 0.80 to 2.30; n = 936; low-quality evidence). This corresponds to 71 more AEs per 1000 participants (95% CI 41 fewer to 264 more per 1000). Study results were limited to a treatment duration of six to 12 weeks.PDEI and AB versus AB alone: the combination of PDEI and AB may provide a small improvement in IPSS-total score (MD 2.56 lower, 95% CI 3.92 lower to 1.19 lower; n = 193; low-quality evidence) compared to AB alone. We found no evidence for BPHII scores. AEs may be increased (RR 2.81, 95% CI 1.53 to 5.17; n = 194; moderate-quality evidence). This corresponds to 235 more AEs per 1000 participants (95% CI 69 more to 542 more per 1000). Study results were limited to treatment duration of four to 12 weeks.PDEI and AB versus PDEI alone: the combination of PDEI and AB may provide a small improvement in IPSS-total (MD 2.4 lower, 95% CI 6.47 lower to 1.67 higher; n = 40; low-quality evidence) compared to PDEI alone. We found no data on BPHII or AEs. Study results were limited to a treatment duration of four weeks.PDEI and 5-ARI versus 5-ARI alone: in the short term (up to 12 weeks), the combination of PDEI and 5-ARI probably results in a small improvement in IPSS-total score (MD 1.40 lower, 95% CI 2.24 lower to 0.56 lower; n = 695; moderate-quality evidence) compared to 5-ARI alone. We found no evidence on BPHII scores or AEs. In the long term (13 to 26 weeks), the combination of PDEI and 5-ARI likely results in a small reduction in IPSS-total score (MD 1.00 less, 95% CI 1.83 lower to 0.17 lower; n = 695; moderate-quality evidence). We found no evidence about effects on BPHII scores. There may be no difference in rates of AEs (RR 1.07, 95% CI 0.84 to 1.36; n = 695; low-quality evidence). This corresponds to 19 more AEs per 1000 participants (95% CI 43 fewer to 98 more per 1000).We found no trials comparing other combinations of treatments or comparing different PDEI agents.

AUTHORS' CONCLUSIONS

Compared to placebo, PDEI likely leads to a small reduction in IPSS-total and BPHII sores, with a possible increase in AEs. There may be no differences between PDEI and AB with regards to improvement in IPSS-total, BPHII, and incidence of AEs. There appears to be no added benefit of PDEI combined with AB compared to PDEI or AB alone or PDEI combined with 5-ARI compared to ARI alone with regards to urinary symptoms. Most evidence was limited to short-term treatment up to 12 weeks and of moderate or low certainty.

No Causal Link between Phosphodiesterase Type 5 Inhibition and Melanoma

Purpose

To examine the association between phosphodiesterase type 5 (PDE5) inhibitor use and melanoma by 1) conducting a systematic review of observational studies; and 2) determining if low PDE5A gene expression in human melanoma correlated with decreased overall survival.

Materials and Methods

A systematic search of observational studies examining the association between PDE5 inhibitor use and melanoma was performed through ClinicalTrials.gov, the Cochrane Library, EMBASE, PubMed, and Web of Science databases, and seven eligible studies were identified. PDE5A gene expression was analyzed with RNA sequencing data from 471 human melanoma samples obtained from The Cancer Genome Atlas.

Results

Four studies reported a positive association between PDE5 inhibitor use and melanoma, and three studies found no correlation. RNA sequencing data analysis revealed that under-expression of the PDE5A gene did not impact clinical outcomes in melanoma.

Conclusions

There is currently no evidence to suggest that PDE5 inhibition in patients causes increased risk for melanoma. The few observational studies that demonstrated a positive association between PDE5 inhibitor use and melanoma often failed to account for major confounders. Nonetheless, the substantial evidence implicating PDE5 inhibition in the cyclic guanosine monophosphate (cGMP)-mediated melanoma pathway warrants further investigation in the clinical setting.

Considerations for Pharmacoepidemiological Studies of Drug-Cancer Associations

In this MiniReview, we provide general considerations for the planning and conduct of pharmacoepidemiological studies of associations between drug use and cancer development. We address data sources, study design, assessment of drug exposure, ascertainment of cancer outcomes, confounder adjustment and future perspectives. Aspects of data sources include assessment of complete history of drug use and data on dose and duration of drug use, allowing estimates of cumulative exposure. Outcome data from formal cancer registries are preferable, but cancer data from other sources, for example, patient or pathology registries, medical records or claims are also suitable. The two principal designs for observational studies evaluating drug-cancer associations are the cohort and case-control designs. A key challenge in studies of drug-cancer associations is the exposure assessment due to the typically long period of cancer development. We present methods to examine early and late effects of drug use on cancer development and discuss the need for employing 'lag-time' in order to avoid reverse causation. We emphasize that a new-user study design should always be considered. We also underline the need for 'dose-response' analyses, as drug-cancer associations are likely to be dose-dependent. Generally, studies of drug-cancer associations should explore risk of site-specific cancer, rather than cancer overall. Additional differentiation may also be crucial for organ-specific cancer with various distinct histological subtypes (e.g., lung or ovary cancer). We also highlight the influence of confounding factors and discuss various methods to address confounding, while emphasizing that the choices of methods depend on the design and specific objectives of the individual study. In some studies, use of active comparator(s) may be preferable. Pharmacoepidemiological studies of drug-cancer associations are expected to evolve considerably in the coming years, due to the increasing availability of long-term data on drug exposures and cancer outcomes, the increasing conduct of multinational studies, allowing studies of rare cancers and subtypes of cancer, and methodological improvements specifically addressing cancer and other long-term outcomes.

Repurposing drugs in oncology (ReDO)-selective PDE5 inhibitors as anti-cancer agents

Selective phosphodiesterase 5 inhibitors, including sildenafil, tadalafil and vardenafil, are widely-used in the treatment of erectile dysfunction and pulmonary arterial hypertension. They are also well-known as examples of successful drug repurposing in that they were initially developed for angina and only later developed for erectile dysfunction. However, these drugs may also be effective cancer treatments. A range of evidentiary sources are assessed in this paper and the case made that there is pre-clinical and clinical evidence that these drugs may offer clinical benefit in a range of cancers. In particular, evidence is presented that these drugs have potent immunomodulatory activity that warrants clinical study in combination with check-point inhibition.

Relation of phosphodiesterase type 5 inhibitors and malignant melanoma: a meta-analysis and systematic review

Data on the association between using PDE5 inhibitors and malignant melanoma are conflicting. To estimate the relation of using PDE5 inhibitors with risk of malignant melanoma, Medline (Ovid) and Embase (Ovid) databases were searched up to February 2017, and a random effects model was used to calculate the summary risk estimates. Five observational studies were included. Five studies reports encompassed a total of 15,979 melanoma cases occurring among 1, 188,414 participants. The pooled multivariable-adjusted RR of melanoma in patients with using PDE5 inhibitors was 1.12 (95% CI: 1.03–1.21, I² = 0.48). Findings from this systematic review support that PDE5 inhibitor use is associated with increased risk of melanoma in ED patients, the result remains inclusive and warrants further study in the future.

Use of phosphodiesterase type 5 inhibitors and risk of melanoma: a meta-analysis of observational studies

Background

Phosphodiesterase type 5 inhibitor (PE5i) administration may stimulate the proliferation and survival of melanocytes. However, discrepancies remain regarding the association between PDE5i use and melanoma risk in observational studies in humans.

Aim

To evaluate the association between PDE5i use and melanoma in a meta-analysis.

Materials and methods

Studies were identified by searching the PubMed and Embase databases. A random-effects model was applied to synthesize the data. A stratified study was performed to evaluate the influence of study characteristics on outcomes.

Results

Four prospective cohort studies and three case–control studies with 1,534,615 male participants and 16,053 melanoma cases were incorporated. Patients who received a PDE5i had a significantly increased risk for melanoma (adjusted risk ratio [RR] =1.12, 95% CI =1.03–1.33, P=0.008) with moderate heterogeneity (I²=54%). Cohort studies (adjusted RR =1.22, 95% CI =1.02–1.46, P=0.03) largely contributed to this result rather than case–control studies. Subsequent stratified analyses revealed that sildenafil was associated with an increased risk of melanoma (adjusted RR =1.26, 95% CI =1.07–1.50, P=0.007), but tadalafil and vardenafil were not. Also, PDE5i use was associated with a significantly increased risk of in situ melanoma (adjusted RR =1.31, 95% CI =1.01–1.69, P=0.04), but not of localized or nonlocalized melanoma.

Conclusion

PDE5i use may be associated with a significantly increased risk for melanoma in men. However, further research is needed to determine whether the association is causative.

Are phosphodiesterase type 5 inhibitors associated with increased risk of melanoma?: A systematic review and meta-analysis

Phosphodiesterase type 5 (PDE5) inhibitors are recommended for patients with erectile dysfunction by American Urological Association and European Association Urology guidelines. However, recent researches have shown that PDE5 inhibitors may lead to increased melanoma risk. Thus, we aimed to explore whether PDE5 inhibitors are associated with increased melanoma risk based on published literatures.We conducted a systematic online search on PubMed, EMBASE, Cochrane Library, Chinese Biochemical Literature, China National Knowledge Infrastructure, and Chinese Science and Technology Periodical databases to identify the related studies. Odds ratios (ORs), risk ratios, and hazard ratios with 95% confidence intervals (CIs) were extracted and calculated to assess the strength of associations between PDE5 inhibitors and melanoma risk. We also extracted the basal cell carcinoma (BCC) to validate the association in this study.We included 5 studies containing 100,932 participants in our systematic review and meta-analysis. The calculated results suggested positive results of PDE5 inhibitors on melanoma risk (OR: 1.13; 95%CI: 1.04-1.23). For localized and nonlocalized melanoma, the results were different (OR: 1.22; 95%CI: 1.04-1.43 for localized melanoma) (OR: 0.62; 95%CI: 0.39-0.98 for nonlocalized melanoma). It also showed that PDE5 inhibitors were associated with increased BCC risk (OR: 1.18; 95%CI: 1.11-1.27).The association between PDE5 inhibitors and melanoma might not be causal due to potential bias (patient selection, and so on) and limitations.

Meta-Analysis of the Association Between Phosphodiesterase Inhibitors (PDE5Is) and Risk of Melanoma

The US Food and Drug Administration recently announced the need to evaluate the association between PDE5is and melanoma. We performed a meta-analysis on the association between PDE5i and melanoma using random effects models and examined whether it met Hill's criteria for causality. A systematic search of Medline, EMBASE, and the Cochrane Library from 1998 to 2016 identified three case-control studies and two cohort studies, including a total of 866 049 men, of whom 41 874 were diagnosed with melanoma. We found a summary estimate indicating an increased risk of melanoma in PDE5i users (relative risk = 1.11, 95% confidence interval = 1.02 to 1.22). However, the association was only statistically significant among men with low PDE5i exposure (not high exposure) and with low-stage melanoma (not high stage), indicating a lack of dose response and biological gradient. PDE5i use was also associated with basal cell cancer, suggesting a lack of specificity and likely confounding by ultraviolet exposure. Thus, although this meta-analysis found a statistically significant association between PDE5i and melanoma, it did not satisfy Hill's criteria for causality.

Potential synergistic effect of phosphodiesterase inhibitors with chemotherapy in lung cancer

Purpose: Lung cancer remains the leading cause of cancer-related deaths worldwide and novel therapeutic approaches targeting crucial pathways are urgently needed to improve its treatment. Differentiation-based therapeutics (Methylxanthines) and phosphodiesterase inhibitors (type 4 and 5), have been implicated in cancer treatment. Our objectives were to capture any potential anti-tumor effect of these drug combinations with chemotherapeutic agents in vitro. Methods: Theophylline as Methylxanthines, Roflumilast as phosphodiesterase type 4 (PDE4) inhibitor and Sildenafil as phosphodiesterase type 5 (PDE5) inhibitor are the drugs that we combined with the chemotherapeutic agents (Docetaxel, Cisplatin and Carboplatin) in vitro. Lung cancer cell lines (NCI-H1048-Small cell lung cancer-SCLC, A549- Non-small cell lung cancer-NSCLC) were purchased from ATCC LGC Standards. At indicated time-point, following 24h and 48h incubation, cell viability and apoptosis were measured with Annexin V staining by flow cytometry. Statistical analysis was performed by GraphPad Prism. Results: In SCLC, following 48h incubation, platinum combinations of carboplatin with roflumilast and sildenafil (p<0.001) and carboplatin with theophylline and sildenafil showed increased apoptosis when compared to carboplatin alone. Concerning the combinations of cisplatin, when combined with roflumilast, theophylline and sildenafil appeared with increased apoptosis of that alone (p<0.001, 24h and 48h incubation). In NSCLC, the 24h incubation was not enough to induce satisfactory apoptosis, except for the combination of cisplatin with roflumilast and theophylline (p<0.05) when compared to cisplatin alone. However, following 48h incubation, carboplatin plus sildenafil, carboplatin plus sildenafil, theophylline and roflumilast showed more cytotoxicity when compared to carboplatin alone (p<0.001). Docetaxel combinations showed no statistically significant results. Conclusion: The synergistic effect of PDE inhibitors with platinum-based agents has been demonstrated in lung cancer. Our suggestion is that these combinations could be used as additive and maintenance treatment in combination to antineoplastic agents in lung cancer patients.

Phosphodiesterase type 5 inhibitors and risk of melanoma: A meta-analysis

BACKGROUND

The association between phosphodiesterase type 5 (PDE5) inhibitors and melanoma risk is controversial.

OBJECTIVE

We quantify the association between use of PDE5 inhibitors and melanoma.

METHODS

We systematically searched PubMed, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, and ClinicalTrials.gov for studies that were conducted up to July 13, 2016, and evaluated the association between PDE5 inhibitors and skin cancer. Random effects meta-analyses were used to calculate the adjusted odds ratio (OR) with the 95% confidence interval (CI).

RESULTS

Five observational studies were included. Compared with PDE5 inhibitor nonuse, PDE5 inhibitor use was slightly but significantly associated with an increased risk for development of melanoma (OR, 1.12; 95% CI, 1.03-1.21) and basal cell carcinoma (OR, 1.14; 95% CI, 1.09-1.19) but not squamous cell carcinoma. For melanoma risk, none of the prespecified factors (dose of PDE5 inhibitor, study design, and study region) significantly affected the results (P > .05). Our sensitivity analysis confirmed the stability of the results.

LIMITATIONS

We included only observational studies, which had some heterogeneities and inconsistent controlling for potential confounders.

CONCLUSIONS

Use of PDE5 inhibitors may be associated with a slightly increased risk for development of melanoma and basal cell carcinoma but not squamous cell carcinoma. However, further large well-conducted prospective studies with adequate adjustment for potential confounders are required for confirmation.