Do Thiazide Diuretics Increase the Risk of Skin Cancer? A Critical Review of the Scientific Evidence and Updated Meta-Analysis

The association between hydrochlorothiazide use and non-melanoma skin cancer in kidney transplant recipients

Background

hydrochlorothiazide (HCTZ) diuretics were correlated with an increased risk of non-melanoma skin cancer (NMSC) and melanoma in the general population. Information is a scarce regarding this effect in kidney transplant recipients who are at increased risk of skin malignancies under immunosuppression.

Methods

Single-center retrospective analysis of adult kidney transplant recipients between 1 January 2010 and 31 December 2015. The primary outcome of the study was the first diagnosis of skin cancer that was removed and pathologically analyzed. Exposure to thiazides was defined as HCTZ use daily for at least one year at a dose of 12.5 mg.

Results

Among 520 kidney transplant recipients, 50 (9.4%) were treated with HCTZ. During a median follow-up of 9.8 years, 67 patients underwent surgical removal and pathological analysis of at least one skin cancer. Exposure to HCTZ during the 3 years following transplantation was associated with an increased risk of skin cancer (P = 0.004). In a multivariate model, there was a significant association between HCTZ exposure and NMSC (HR 2.54, 95%CI 1.26-5.15, P = 0.007). There was a higher rate of basal cell carcinoma with HCTZ exposure, according to both univariate and multivariate analyses (HR 2.61, 95%CI 1.06-6.43, P = 0.037) and (HR 3.03, 95%CI 1.22-7.55, P = 0.017, respectively). However, no significant association was observed between HCTZ exposure and squamous cell carcinoma.

Conclusions

These findings suggest a benefit of increased frequency of dermatologist inspection in kidney transplant recipients receiving HCTZ especially in increased ultraviolet exposure area.

Photosensibilisierende Antihypertensiva und das Hautkrebsrisiko bei postmenopausalen Frauen: Photosensitizing antihypertensive medication and risk of skin cancer among postmenopausal women

Hintergrund

Es gibt nur wenige prospektive Studien, die die Dosis‐Wirkungs‐Beziehung zwischen der Anwendung einiger photosensibilisierender Antihypertensiva und Hautkrebs untersucht haben.

Patienten und Methodik

Anhand prospektiver Daten aus der Women's Health Initiative Observational Study untersuchten wir den Zusammenhang zwischen der Anwendung von Antihypertensiva und dem Risiko für nicht melanozytären Hautkrebs (NMSC) und dem Melanom bei postmenopausalen Frauen im Alter von 50–79 Jahren (n = 64 918). Dabei wurden multivariable Cox‐Regressionsmodelle (Proportional‐Hazard‐Modelle) verwendet und Hazard Ratios (HR) sowie 95%‐Konfidenzintervalle (KI) berechnet.

Ergebnisse

8777 NMSC und 1227 Melanom‐Fälle wurden beobachtet. Die Anwendung von Antihypertensiva (HR [95%‐KI]: 1,12 [1,07–1,18]), ACE‐Hemmern (1,09 [1,01–1,18]), Kalziumkanalblockern (1,13 [1,05–1,22]), Diuretika (1,20 [1,12–1,27]), Schleifendiuretika (1,17 [1,07–1,28]) und Thiaziden (1,17 [1,03–1,33]) war jeweils mit einem erhöhten NMSC‐Risiko assoziiert. Das NMSC‐Risiko stieg linear mit der Anwendung mehrerer Antihypertensiva (p‐Trend = 0,02) und mit zunehmender Anwendungsdauer (p‐Trend < 0,01) an. Antihypertensiva (1,15 [1,00–1,31]), Angiotensin‐II‐Rezeptorblocker (1,82 [1,05–3,15]) und Diuretika (1,34 [1,13–1,59]) waren jeweils mit einem erhöhten Melanomrisiko assoziiert. Zwischen der Anwendung von Antihypertensiva und der Melanom‐Inzidenz wurde eine Effektmodifikation durch Exposition gegenüber Sonnenlicht‐Exposition beobachtet (p‐Interaktion = 0,02).

Schlussfolgerungen

Die Anwendung von Antihypertensiva allgemein und einiger einzelner Klassen von Antihypertensiva ging mit einer erhöhten Inzidenz von NMSC und Melanomen einher, wobei eine Dosis‐Wirkungs‐Beziehung bestand.

The phenomenon of phototoxicity and long-term risks of commonly prescribed and structurally diverse drugs

Photosensitivity to structurally diverse drugs is a common but under-reported adverse cutaneous reaction and can be classified as phototoxic or photoallergic. Phototoxic reactions occur when the skin is exposed to sunlight after administering topical or systemic medications that exhibit photosensitizing activity. These reactions depend on the dose of medication, degree of exposure to ultraviolet light, type of ultraviolet light, and sufficient skin distribution volume. Accurate prediction of the incidence and phototoxic response severity is challenging due to a paucity of literature, suggesting that phototoxicity may be more frequent than reported. This paper reports an extensive literature review on phototoxic drugs; the review employed pre-determined search criteria that included meta-analyses, systematic reviews, literature reviews, and case reports freely available in full text. Additional reports were identified from reference sections that contributed to the understanding of phototoxicity. The following drugs and/or drug classes are discussed: amiodarone, voriconazole, chlorpromazine, doxycycline, fluoroquinolones, hydrochlorothiazide, nonsteroidal anti-inflammatory drugs, and vemurafenib. In reviewing phototoxic skin reactions, this review highlights drug molecular structures, their reactive pathways, and, as there is a growing association between photosensitizing drugs and the increasing incidence of skin cancer, the consequential long-term implications of photocarcinogenesis.

Photosensitizing antihypertensive medication and risk of skin cancer among postmenopausal women

BACKGROUND

Few prospective studies exist with an evaluation of a dose-response relationship between use of some photosensitizing antihypertensive medications and skin cancer.

PATIENT AND METHODS

We used prospective data from the Women's Health Initiative Observational Study to investigate the association between antihypertensive use and risk of non-melanoma skin cancer (NMSC) and melanoma in postmenopausal women aged 50-79 years at baseline (n  =  64,918). Multivariable Cox proportional hazards regression models were used and hazard ratios (HRs) and 95 confidence intervals (CIs) were calculated.

RESULTS

8,777 NMSC and 1,227 melanoma cases were observed. Use of antihypertensives (HR [95% CI]: 1.12 [1.07-1.18]), ACE inhibitors (1.09 [1.01-1.18]), calcium channel blockers (1.13 [1.05-1.22]), diuretics (1.20 [1.12-1.27]), loop diuretics (1.17 [1.07-1.28]), and thiazides (1.17 [1.03-1.33]) were each associated with higher NMSC risk. NMSC risk linearly increased with use of multiple antihypertensives (p-trend  =  0.02) and with longer duration of use (p-trend < 0.01). Antihypertensives (1.15 [1.00-1.31]), angiotensin-II receptor blockers (1.82 [1.05-3.15]), and diuretics (1.34 [1.13-1.59]) were each associated with elevated melanoma risk. Effect modification by solar radiation exposure was found between antihypertensive use and incidence of melanoma (p-interaction  =  0.02).

CONCLUSIONS

Use of antihypertensives overall, and several individual classes thereof, were associated with higher incidence of NMSC and melanoma with dose-response relationship.

What is the relationship between photosensitizing drugs and skin cancer?

ABSTRACT

Many medications are associated with phototoxicity or photoallergy, the two types of photosensitivity. Recently, a warning related to increased skin cancer risk was added to the labeling of the popular diuretic hydrochlorothiazide. This article reviews some photosensitizing medications and describes patient education on preventing and recognizing photosensitivity reactions and skin cancer.

The effects of exposure to solar radiation on human health

This assessment by the Environmental Effects Assessment Panel (EEAP) of the Montreal Protocol under the United Nations Environment Programme (UNEP) evaluates the effects of ultraviolet (UV) radiation on human health within the context of the Montreal Protocol and its Amendments. We assess work published since our last comprehensive assessment in 2018. Over the last four years gains have been made in knowledge of the links between sun exposure and health outcomes, mechanisms, and estimates of disease burden, including economic impacts. Of particular note, there is new information about the way in which exposure to UV radiation modulates the immune system, causing both harms and benefits for health. The burden of skin cancer remains high, with many lives lost to melanoma and many more people treated for keratinocyte cancer, but it has been estimated that the Montreal Protocol will prevent 11 million cases of melanoma and 432 million cases of keratinocyte cancer that would otherwise have occurred in the United States in people born between 1890 and 2100. While the incidence of skin cancer continues to rise, rates have stabilised in younger populations in some countries. Mortality has also plateaued, partly due to the use of systemic therapies for advanced disease. However, these therapies are very expensive, contributing to the extremely high economic burden of skin cancer, and emphasising the importance and comparative cost-effectiveness of prevention. Photodermatoses, inflammatory skin conditions induced by exposure to UV radiation, can have a marked detrimental impact on the quality of life of sufferers. More information is emerging about their potential link with commonly used drugs, particularly anti-hypertensives. The eyes are also harmed by over-exposure to UV radiation. The incidence of cataract and pterygium is continuing to rise, and there is now evidence of a link between intraocular melanoma and sun exposure. It has been estimated that the Montreal Protocol will prevent 63 million cases of cataract that would otherwise have occurred in the United States in people born between 1890 and 2100. Despite the clearly established harms, exposure to UV radiation also has benefits for human health. While the best recognised benefit is production of vitamin D, beneficial effects mediated by factors other than vitamin D are emerging. For both sun exposure and vitamin D, there is increasingly convincing evidence of a positive role in diseases related to immune function, including both autoimmune diseases and infection. With its influence on the intensity of UV radiation and global warming, the Montreal Protocol has, and will have, both direct and indirect effects on human health, potentially changing the balance of the risks and benefits of spending time outdoors.

Increased risk of metastasis in patients with incidental use of renin-angiotensin system inhibitors: a retrospective analysis for multiple types of cancer based on electronic medical records

Renin-angiotensin system inhibitors have been shown to prevent cancer metastasis in experimental models, but there are limited data in clinical studies. We aimed to explore whether renin-angiotensin system inhibitors administered during the period of cancer resection can influence the subsequent development of metastasis by analyzing multiple individual types of primary cancers. A total of 4927 patients who had undergone resection of primary cancers at Kyushu University Hospital from 2009 to 2014 were enrolled and categorized into 3 groups based on the use of antihypertensive drugs: renin-angiotensin system inhibitors, other drugs, and none. Cumulative incidence functions of metastasis, treating death as a competing risk, were calculated, and the difference was examined among groups by Gray's test. Fine and Gray's model was employed to evaluate multivariate-adjusted hazards of incidental metastasis. In the multivariate-adjusted analysis, patients with skin and renal cancers showed statistically higher risks of metastasis with the use of renin-angiotensin system inhibitors (hazard ratio [95% confidence interval], 5.81 [1.07-31.57] and 4.24 [1.71-10.53], respectively). Regarding pancreatic cancer, patients treated with antihypertensive drugs other than renin-angiotensin system inhibitors had a significantly increased risk of metastasis (hazard ratio [95% confidence interval], 3.31 [1.43-7.69]). Future larger studies are needed to ascertain whether renin-angiotensin system inhibitors can increase the risk of metastasis in skin and renal cancers, focusing on specific tissue types and potential factors associated with renin-angiotensin system inhibitor use.

Use of antihypertensive drugs and risk of cutaneous melanoma: a nationwide nested case-control study

Background

Most antihypertensives can induce dermal photosensitivity, which may increase melanoma risk. However, corroborating evidence is limited. We examined the associations between use of antihypertensives and melanoma risk.

Methods

A nationwide nested case-control study was conducted using data from the Cancer Registry of Norway, the National Registry and the Norwegian Prescription Database in 2004–15. Ten controls were randomly selected for each melanoma case, matched on sex and birth year. The study included 12 048 cases and 117 895 controls. We estimated rate ratios (RRs) with 95% confidence intervals (CIs). All analyses were adjusted for ambient ultraviolet radiation (UVR). We additionally performed active comparator analyses, and sensitivity analyses by only including new users, distinguishing between exclusive and mixed users, allowing for different latency periods, and subgroup analyses by melanoma subtype and clinical stage.

Results

Compared with non-use, we observed a slightly increased melanoma risk in users of diuretics (RR 1.08, CI 1.01–1.15), calcium-channel blockers (RR 1.10, CI 1.04–1.18) and drugs affecting the renin-angiotensin system (RR 1.10, CI 1.04–1.16), but not for beta blockers (RR 0.97, CI 0.92–1.03). We found no heterogeneity of associations by melanoma subtype or clinical stage and no dose-response relationship between the cumulative defined daily doses (DDDs) and melanoma. No interaction was found between cumulative DDDs and ambient UVR.

Conclusions

Weak associations, with lack of a dose-response relationship and lack of interactions with ambient UVR, in the DDD analysis in this nationwide study do not support a causal relationship between antihypertensives and melanoma risk.

Associations of thiazide use with skin cancers: a systematic review and meta-analysis

BACKGROUND

Previous findings on the associations of thiazide use with skin cancers were conflicting. This study aimed to examine the associations of individual thiazide use with skin cancer risk, differentiated by subtypes of skin cancers, geographic regions, and cumulative doses of individual thiazides.

METHODS

We searched PubMed, Embase, and Cochrane Central Register of Controlled Trials for relevant studies on January 5, 2022, scanned the references of included studies, and consulted experts. We included case-control and cohort studies or randomized trials reporting the associations of individual thiazide or thiazide-like diuretics use with skin cancers. Non-melanoma skin cancer (NMSC) and melanoma were analysed separately. A random-effects model meta-analysis was conducted for pooled odds ratio (OR) and hazard ratio (HR) for skin cancers related to individual thiazide use.

RESULTS

We included 15, 5, and 5 case-control or cohort studies reporting the risk for skin cancers associated with hydrochlorothiazide, bendroflumethiazide, and indapamide use, respectively, with 17,848,313 participants. The meta-analysis showed associations of hydrochlorothiazide use with increased risk of NMSC (OR 1.16, 95% CI 1.08-1.24; HR 1.26, 95% CI 1.04-1.54), squamous cell carcinoma (SCC) (OR 1.32, 95% CI 1.06-1.65; HR 1.61, 95% CI 0.97-2.67), and melanoma (OR 1.11, 95% CI 1.02-1.20; HR 1.03, 95% CI 0.93-1.14). The increased risks for SCC were associated with high cumulative doses of hydrochlorothiazide (OR 2.56, 95% CI 1.43-4.57; HR 1.20, 95% CI 1.00-1.45). Hydrochlorothiazide use was associated with different subtypes of melanoma including superficial spreading (OR 1.18, 95% CI 1.05-1.33), nodular (OR 1.23, 95% CI 1.08-1.39), and lentigo maligna melanoma (OR 1.33, 95% CI 1.08-1.65). Various cumulative doses of hydrochlorothiazide were associated with increased odds for melanoma. However, the associations of hydrochlorothiazide use with increased risk of NMSC and melanoma only appeared in non-Asian countries. No meaningful increase in the risk for skin cancers was associated with bendroflumethiazide and indapamide.

CONCLUSIONS

Hydrochlorothiazide is associated with an increased risk for NMSC (especially SCC) and melanoma in non-Asian countries, whereas bendroflumethiazide and indapamide are not associated with a meaningful risk for skin cancers. Healthcare professionals and patients should be informed of the different risk profiles of skin cancers associated with different thiazides, cumulative doses, and regions.

TRIAL REGISTRATION

PROSPERO CRD42021234317 .

Use of Thiazide Diuretics and Risk of All Types of Skin Cancers: An Updated Systematic Review and Meta-Analysis

Background: The use of thiazide diuretics is associated with skin cancer risk; however, whether this applies to all skin cancer types is unclear. Methods: In this meta-analysis, we searched multiple electronic databases and gray literature up to 10 April 2022, with no language restrictions, to identify relevant randomized controlled trials (RCTs) and non-randomized studies (cohort, case-control) that investigated the association between thiazide diuretics and skin cancer. The primary outcomes of interest were malignant melanoma and non-melanoma skin cancer (basal cell carcinoma [BCC], squamous cell carcinoma [SCC]). Secondary outcomes included other skin cancers (lip cancer, Merkel cell carcinoma, malignant adnexal skin tumors, oral cavity cancer, and precursors of skin cancer). We used a random-effects meta-analysis to estimate pooled adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Results: Thirty non-randomized studies (17 case-control, 13 cohort, no RCTs) were included. Thiazide diuretic users had a higher risk of malignant melanoma (17 studies; n = 10,129,196; pooled adjusted OR, 1.10; 95% CI, 1.04−1.15; p < 0.001; strength of evidence, very low; very small harmful effect), BCC (14 studies; n = 19,780,476; pooled adjusted OR, 1.05; 95% CI, 1.02−1.09; p = 0.003; strength of evidence, very low; very small harmful effect), and SCC (16 studies; n = 16,387,862; pooled adjusted OR, 1.35; 95% CI, 1.22−1.48; p < 0.001; strength of evidence, very low; very small harmful effect) than non-users. Thiazide diuretic use was also associated with a higher risk of lip cancer (5 studies; n = 161,491; pooled adjusted OR, 1.92; 95% CI, 1.52−2.42; p < 0.001; strength of evidence, very low; small harmful effect), whereas other secondary outcomes were inconclusive. Conclusions: Thiazide diuretics are associated with the risk of all skin cancer types, including malignant melanoma; thus, they should be used with caution in clinical practice.

Molecular mechanisms altering tubular calcium reabsorption

The majority of calcium filtered by the glomerulus is reabsorbed along the nephron. Most is reabsorbed from the proximal tubule (> 60%) via a paracellular pathway composed of the tight junction proteins claudins-2 and -12, a process driven by sodium and consequently water reabsorption. The thick ascending limb reabsorbs the next greatest amount of calcium (20-25%), also by a paracellular pathway composed of claudins-16 and -19. This pathway is regulated by the CaSR, whose activity increases the expression of claudin-14, a protein that blocks paracellular calcium reabsorption. The fine tuning of urinary calcium excretion occurs in the distal convoluted and connecting tubule by a transcellular pathway composed of the apical calcium channel TRPV5, the calcium shuttling protein calbindin-D_28K and the basolateral proteins PMCA1b and the sodium calcium exchanger, NCX. Not surprisingly, mutations in a subset of these genes cause monogenic disorders with hypercalciuria as a part of the phenotype. More commonly, "idiopathic" hypercalciuria is encountered clinically with genetic variations in CLDN14, the CASR and TRPV5 associating with kidney stones and increased urinary calcium excretion. An understanding of the molecular pathways conferring kidney tubular calcium reabsorption is employed in this review to help explain how dietary and medical interventions for this disorder lower urinary calcium excretion.

The Use of Antihypertensive Drugs as Coadjuvant Therapy in Cancer

Cancer is a complex group of diseases that constitute the second largest cause of mortality worldwide. The development of new drugs for treating this disease is a long and costly process, from the discovery of the molecule through testing in phase III clinical trials, a process during which most candidate molecules fail. The use of drugs currently employed for the management of other diseases (drug repurposing) represents an alternative for developing new medical treatments. Repurposing existing drugs is, in principle, cheaper and faster than developing new drugs. Antihypertensive drugs, primarily belonging to the pharmacological categories of angiotensin-converting enzyme inhibitors, angiotensin II receptors, direct aldosterone antagonists, β-blockers and calcium channel blockers, are commonly prescribed and have well-known safety profiles. Additionally, some of these drugs have exhibited pharmacological properties useful for the treatment of cancer, rendering them candidates for drug repurposing. In this review, we examine the preclinical and clinical evidence for utilizing antihypertensive agents in the treatment of cancer.

Photosensitizing Medications and Skin Cancer: A Comprehensive Review

(1) The incidence of skin cancer is increasing in the United States (US) despite scientific advances in our understanding of skin cancer risk factors and treatments. In vitro and in vivo studies have provided evidence that suggests that certain photosensitizing medications (PSMs) increase skin cancer risk. This review summarizes current epidemiological evidence on the association between common PSMs and skin cancer. (2) A comprehensive literature search was conducted to identify meta-analyses, observational studies and clinical trials that report on skin cancer events in PSM users. The associated risks of keratinocyte carcinoma (squamous cell carcinoma and basal cell carcinoma) and melanoma are summarized, for each PSM. (3) There are extensive reports on antihypertensives and statins relative to other PSMs, with positive and null findings, respectively. Fewer studies have explored amiodarone, metformin, antimicrobials and vemurafenib. No studies report on the individual skin cancer risks in glyburide, naproxen, piroxicam, chlorpromazine, thioridazine and nalidixic acid users. (4) The research gaps in understanding the relationship between PSMs and skin cancer outlined in this review should be prioritized because the US population is aging. Thus the number of patients prescribed PSMs is likely to continue to rise.

The Relationship Between Anti-Hypertensive Drugs and Cancer: Anxiety to be Resolved in Urgent

Hypertension is the prevailing independent risk factor for cardiovascular disease worldwide. Anti-hypertensive drugs are the common and effective cure for lowering blood pressure in patients with hypertension. However, some large-scale clinical studies have pointed out that long-term ingestion of some oral anti-hypertensive drugs was associated with risks of incident cancer and the survival time. In contrast, other studies argue that anti-hypertensive drugs are not related to the occurrence of cancer, even as a complementary therapy of tumor treatment. To resolve the dispute, numerous recent mechanistic studies using animal models have tried to find the causal link between cancer and different anti-hypertensive drugs. However, the results were often contradictory. Such uncertainties have taken a toll on hypertensive patients. In this review, we will summarize advances of longitudinal studies in the association between anti-hypertensive drugs and related tumor risks that have helped to move the field forward from associative to causative conclusions, in hope of providing a reference for more rigorous and evidence-based clinical research on the topic to guide the clinical decision making.

Use of Hydrochlorothiazide and Risk of Melanoma and Nonmelanoma Skin Cancer

INTRODUCTION

There are concerns that hydrochlorothiazide may increase the risk of incident nonmelanoma (cutaneous squamous cell carcinoma [cSCC], basal cell carcinoma [BCC]) and melanoma skin cancer, with regulatory agencies and societies calling for additional studies.

METHODS

We conducted a propensity score-matched population-based cohort study using the United Kingdom Clinical Practice Research Datalink. A total of 20,513 new users of hydrochlorothiazide were propensity score matched, in a 1:1 ratio, to new users of other thiazide diuretics between January 1, 1988 and March 31, 2018, with follow-up until March 31, 2019. Cox proportional hazards models were used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for cSCC, BCC, and melanoma, comparing use of hydrochlorothiazide with use of other thiazide diuretics overall, by cumulative duration of use, and cumulative dose.

RESULTS

After an 8.6-year median follow-up, hydrochlorothiazide was associated with an increased risk of cSCC (HR 1.50, 95% CI 1.06-2.11). HRs increased with cumulative duration of use, with evidence of an association after 5-10 years (HR 2.10, 95% CI 1.20-3.67) and highest after > 10 years (HR 3.70, 95% CI 1.77-7.73). Similarly, HRs increased with cumulative dose, with higher estimates for ≥ 100,000 mg (HR 4.96, 95% CI 2.51-9.81). In contrast, hydrochlorothiazide was not associated with an increased risk of BCC (HR 1.01, 95% CI 0.91-1.13) or melanoma (HR 0.82, 95% CI 0.63-1.08), with no evidence of duration- or dose-response relationships.

CONCLUSIONS

Use of hydrochlorothiazide was associated with an increased risk of cSCC and with evidence of a duration- and dose-response relationship. In contrast, no association was observed for BCC or melanoma.

Recent Warnings about Antihypertensive Drugs and Cancer Risk: Where Do They Come From?

The recent decrease in mortality related to cardiovascular diseases has largely been due to the more effective treatment of cardiovascular risk factors and secondary prevention therapies. More people than ever are now on long-term medications. Hypertension, which is one of the most common cardiovascular risk factors, requires life-long treatment. Recent evidence has focused attention on the risk of cancer that may be associated with the long-term use of antihypertensive therapy. This article summarises available evidence surrounding three recent events in this setting. Even though this is a crucial patient safety issue, there are no conclusive answers at this time and further studies are required.