Risk of nonmelanoma skin cancer in patients with inflammatory bowel disease who use thiopurines is not increased

Inflammatory Bowel Disease and Skin Cancer: A Two-Sample Mendelian Randomization Analysis

Background: At present, numerous clinical studies suggest a correlation between inflammatory bowel disease (IBD) and skin cancer. However, some articles present differing views that IBD does not increase the risk of skin cancer. The presence of potential reverse causality and residual confounding is inherent in conventional observational studies. Thus, this study used a two-sample Mendelian randomization (MR) study design to estimate the causal effect of IBD on the risk of skin cancer, including cutaneous malignant melanoma (CMM, also named melanoma skin cancer) and nonmelanoma skin cancer (NMSC). Design: In this study, a two-sample MR analysis was used to estimate the causal effect of IBD on skin cancer outcomes. The inverse-variance weighted (IVW) method was used as the main MR analysis, with multiple sensitivity analyses conducted to assess the robustness of findings. Results: In examining the association between IBD and NMSC, all p-values of the IVW methods were found to be <0.05, providing evidence for a causal effect of IBD on an increased risk of NMSC. However, IVW for IBD on CMM yielded p-values >0.05, indicating no causal relationship between IBD and CMM. These findings were consistent across other MR methods, with no evidence of pleiotropy or heterogeneity. Sensitivity analyses confirmed the robustness of our results. Conclusion: Using MR analysis, we found evidence for a causal effect of genetic liability for IBD on an increased risk of NMSC. However, our study did not find sufficient evidence to support a significant impact of IBD on CMM outcomes.

Cumulative thiopurine dosing and keratinocyte skin cancer in inflammatory bowel disease: a case-control study

BACKGROUND AND AIM

Patients with inflammatory bowel disease (IBD) treated with thiopurines are at increased risk of keratinocyte skin cancer (KSC). Most international guidelines recommend yearly dermatological screening of thiopurine-treated patients. Whether the association between the development of KSC and the use of thiopurines is dose-dependent remains unclear. The aim of this study was to investigate the association between the cumulative thiopurine dose and KSC development in patients with IBD which can be helpful to assist in further skin cancer risk stratification and personalization of screening recommendations in patients with IBD.

METHODS

We performed a single-center case-control study, including patients with IBD with and without a history of KSC (cases and controls, respectively). The primary outcome was the association of cumulative azathioprine, mercaptopurine and thioguanine dose with KSC development. Univariable and multivariable logistic regression analyses were performed, the latter corrected for age and smoking, known risk factors of KSC.

RESULTS

We included 50 cases and 150 controls, predominantly white population. Age and current azathioprine use were univariably significantly associated with KSC development. In multivariable logistic regression analyses, age at inclusion remained significantly associated. Cumulative doses of thiopurines (separate or combined) or duration of thiopurine use did not impact KSC risk, also after correcting for age and smoking.

CONCLUSION

Cumulative thiopurine dose and duration did not show an association with KSC development. Future KSC risk stratification, based on all available KSC risk factors, may aid in selecting individuals who can benefit most from dermatologic screening programs.

Minimal risk of lymphoma and non-melanoma skin cancer despite long-term use of thiopurines in patients with inflammatory bowel disease: A longitudinal cohort analysis from northern India

BACKGROUND AND AIM

Thiopurines are widely used to maintain remission in both ulcerative colitis (UC) and Crohn's disease (CD). Reported effectiveness and tolerability rates have been variable across studies. There are only sparse data in Asian population regarding the long-term efficacy and safety of thiopurines.

METHODS

Records of 5351 patients followed up at inflammatory bowel disease (IBD) clinic, All India Institute of Medical Sciences, New Delhi from 2004 to 2020 were evaluated retrospectively. Safety was evaluated in terms of long-term adverse events and development of malignancy.

RESULTS

Of 5351 patients with IBD, 1093 who received thiopurine for > 3 months (UC = 788 [proctitis-1.9%, left-sided colitis-44.9%, & pancolitis-53.1%] & CD = 305 [inflammatory-42.6%, stricturing-46.9%, & fistulizing-10.5%]) were included (60.8%-male patients). Follow up and treatment duration on thiopurine were 7 (4-12) years and 39.4 ± 40.3 months, respectively, with 254 (23.2%) patients receiving thiopurines for more than 5 and 68 (6.2%) receiving for more than 10 years. Three hundred and fifty-nine (UC: 249 [31.6%]; CD: 110 [36.1%]; P = 0.1) patients developed adverse events; commonest was myelosuppression (23.4%) followed by gastrointestinal intolerance (3%), flu-like illness (1.7%), and arthralgia/myalgia (1.4%). Myelosuppression was the commonest cause of thiopurine withdrawal. No patient (including 254 patients on thiopurine for ≥ 5 years) developed lymphoma or non-melanoma skin cancer. The cumulative probability of staying free from adverse events in overall IBD cohort at 1, 2, and 5 years was 78.6%, 71.9%, and 68.4%, respectively, and this was comparable between UC and CD (P = 0.09).

CONCLUSION

Long-term follow up of patients with IBD from northern India on thiopurine monotherapy demonstrated minimal risk of development of lymphoma as well as non-melanoma skin cancer.

Solid extraintestinal malignancies in patients with inflammatory bowel disease

Malignancies constitute the second cause of death in patients with inflammatory bowel diseases (IBD), after cardiovascular diseases. Although it has been postulated that IBD patients are at greater risk of colorectal cancer compared to the general population, lately there has been evidence supporting that this risk is diminishing over time as a result of better surveillance, while the incidence of extraintestinal cancers (EICs) is increasing. This could be attributed either to systemic inflammation caused by IBD or to long-lasting immunosuppression due to IBD treatments. It seems that the overall risk of EICs is higher for Crohn’s disease patients and it is mainly driven by skin cancers, and liver-biliary cancers in patients with IBD and primary sclerosing cholangitis. The aims of this review were first to evaluate the prevalence, characteristics, and risk factors of EICs in patients with IBD and second to raise awareness regarding a proper surveillance program resulting in early diagnosis, better prognosis and survival, especially in the era of new IBD treatments that are on the way.

Level of UV Exposure, Skin Type, and Age Are More Important than Thiopurine Use for Keratinocyte Carcinoma Development in IBD Patients

BACKGROUND

Retrospective studies observe an increased risk of keratinocyte carcinomas (KCs) in patients with inflammatory bowel disease (IBD) on thiopurine (TP) medication. The role of traditional risk factors such as skin type and sun protection behavior has not been studied in this population. This study aimed to examine traditional KC risk factors and thiopurine use on skin cancer development in an IBD cohort.

METHODS

Consecutive IBD patients were recruited from four specialist centers in Australia and New Zealand, each with varying UV exposure indices. Data pertaining to race, skin color, freckling and sun protection behavior, dose of TP therapy, and skin cancer development were elicited through a self-reported questionnaire.

RESULTS

A total of 691 IBD patients were included with 62 reporting KC development. Thiopurine usage was similar among patients who developed skin cancer compared with those who did not (92% vs. 89%, p = 0.3). There was no statistically significant association between KC development and TP dose or 6-thioguanine nucleotide levels. In multivariate modeling, four factors were independently and significantly associated with KC: age over 61 years old versus less than 30 years old (OR 6.76; 95% CI 2.38-19.18), residing in Brisbane versus Christchurch (OR 3.3; 95% CI 1.6-6.8), never staying in the shade versus staying in the shade ≥ 50% of the time (OR 3.8; 95% CI 1.4-10.5), and having a skin type that never tanned versus other skin types (OR 6.9; 95% CI 2.9-16.0).

CONCLUSION

Skin type, age, and sun protection behavior are more important risk factors for KC development than thiopurine medication use in this IBD population.

Nonmelanoma Skin Cancer Risk in Patients With Inflammatory Bowel Disease Undergoing Thiopurine Therapy: A Systematic Review of the Literature

BACKGROUND

Azathioprine and 6-mercaptopurine (thiopurines) are common adjunct treatments for inflammatory bowel disease (IBD). Although thiopurine therapy in organ transplant recipients is known to increase nonmelanoma skin cancers (NMSCs), dermatologic literature yields less data regarding NMSC risk of thiopurine use in IBD.

OBJECTIVE

The aim of this study was to systematically review current literature on NMSC risk in patients with IBD using thiopurine therapy.

METHODS

Systematic review of PubMed was performed with keywords "inflammatory bowel disease," "ulcerative colitis," "Crohn's disease," "thiopurine," "azathioprine," "6-mercaptopurine," "skin cancer," "non-melanoma," "squamous cell carcinoma," and "basal cell carcinoma." All available publication years were included. Publications were evaluated using PRISMA guidelines.

RESULTS

The systematic review yielded 67 articles; 18 met final inclusion criteria.

LIMITATIONS

Heterogeneity of study designs limited direct comparisons of thiopurine exposure and NMSC risk.

CONCLUSION

Patients with IBD using thiopurines seem to have a moderately increased risk of NMSC that is proportional to therapy duration. Risk of NMSC seems to decrease or return to baseline after discontinuing therapy, although additional data are needed to support this trend. Younger patients with IBD using thiopurines seem to be at greater risk of NMSC. Appreciating NMSC risk in patients with IBD undergoing thiopurine therapy should help direct skin cancer screening recommendations and sun protective measures.

Impact of New Treatments on Hospitalisation, Surgery, Infection, and Mortality in IBD: a Focus Paper by the Epidemiology Committee of ECCO

The medical management of inflammatory bowel disease has changed considerably over time with wider use of immunosuppressant therapy and the introduction of biological therapy. To what extent this change of medical paradigms has influenced and modified the disease course is incompletely known. To address this issue, an extensive review of the literature has been carried out on time trends of hospitalization, surgery, infections, cancer, and mortality rates in inflammatory bowel disease [IBD] patients. Preference was given to population-based studies but, when data from these sources were limited, large cohort studies and randomised controlled trials were also considered. In general, data on hospitalisation rates are strikingly heterogeneous and conflicting. In contrast, the consistent drop in surgery/colectomy rates suggests that the growing use of immunosuppressants and biological agents has had a positive impact on the course of IBD. Most clinical trial data indicate that the risk of serious infections is not increased in patients treated with anti-tumour necrosis factor alpha [TNFα] agents, but a different picture emerges from cohort studies. The use of thiopurines increases the risk for non-melanoma skin cancers and to a lesser extent for lymphoma and cervical cancer [absolute risk: low], whereas no clear increase in the cancer risk has been reported for anti-TNF agents. Finally, the majority of studies reported in the literature do not reveal any increase in mortality with immunosuppressant therapy or biologicals/anti-TNF agents.

Cancer and immunomodulators in inflammatory bowel diseases

The widespread use of thiopurines and anti-tumor necrosis factors (TNFs) in inflammatory bowel disease (IBD) is a rising concern regarding their potential cancer risk. MEDLINE, EMBASE, and the Cochrane Library database were searched for articles regarding immunomodulators anti-TNF agents in IBD, hematologic malignancies, and solid tumors. Current evidences support that thiopurines and anti-TNFs used alone or in combination do not increase the overall cancer risk in IBD. Thiopurines use, with or without anti-TNFs, is associated with an increased risk of lymphoma, particularly non-Hodgkin lymphoma, in Crohn's disease. Combined treatment significantly increases the risk of a rare hepatosplenic T-cell lymphoma, particularly in young male patients with Crohn's disease. An increased risk of nonmelanotic skin cancer is also observed when using thiopurines in IBD, whereas a slightly increased risk of melanoma is observed when using anti-TNFs. The role played by immunomodulators in the development of other cancer types (i.e., urinary) as also by the severity of IBD is under investigation. Although the incidence of specific malignancies (lymphoma, skin cancers) seems to be increased by immunomodulators, their absolute number is low. As thiopurines and anti-TNFs are highly effective in IBD, current evidences support that in appropriate hands, their benefits overwhelm the cancer risk. However, a careful selection of both patients and timing of treatment is mandatory, particularly in young male patients with Crohn's disease. Immunomodulators should therefore be handled by experienced and dedicated gastroenterologists who aware of the potential, although low, cancer risk associated with their use in patients with IBD.

Chemoprevention of colorectal cancer

Colorectal cancer has become one of the most prevalent malignant diseases for both men and women. Patients with inflammatory bowel diseases or certain inherited cancer syndromes are at high risk of developing colorectal cancer and have naturally the highest need for cancer prevention. In familial adenomatous polyposis (FAP) and Lynch syndrome, most of the underlying germline mutations can be detected by DNA sequencing, and medical counselling of affected individuals involves both surveillance tests and chemopreventive measures. However, as the mechanisms leading to colorectal cancer differ in these high-risk groups, the molecular action of chemopreventive drugs needs to be adjusted to the certain pathway of carcinogenesis. In the last decades, a number of drugs have been tested, including sulindac, aspirin, celecoxib, and mesalazine, but some of them are still controversially discussed. This review summarizes the advances and current standards of colorectal cancer prevention in patients with inflammatory bowel disease, FAP and Lynch syndrome.

Increased risk of malignancy with adalimumab combination therapy, compared with monotherapy, for Crohn's disease

BACKGROUND & AIMS

Few studies have assessed the risk of malignancy from anti-tumor necrosis factor monotherapy or combination therapy for Crohn's disease (CD). We determined the relative risk of malignancy in patients with CD who received adalimumab monotherapy, compared with the general population. We also compared the risk of malignancy associated with combination adalimumab and immunomodulator therapy with that of adalimumab monotherapy.

METHODS

We performed a pooled analysis of data from 1594 patients with CD who participated in clinical trials of adalimumab (CLASSIC I and II, CHARM, GAIN, EXTEND, and ADHERE studies; 3050 patient-years of exposure). We calculated rates of malignancy among patients; the expected rates of malignancy, based on the general population, were derived from the Surveillance, Epidemiology, and End Results registry and National Cancer Institute survey.

RESULTS

Compared with the general population, patients receiving adalimumab monotherapy did not have a greater than expected incidence of nonmelanoma skin cancer (NMSC) or other cancers, whereas those receiving combination therapy had a greater than expected incidence of malignancies other than NMSC (standardized incidence ratio, 3.04; 95% confidence interval [CI], 1.66-5.10) and of NMSC (standardized incidence ratio, 4.59; 95% CI, 2.51-7.70). Compared with patients receiving adalimumab monotherapy, those patients receiving combination therapy had an increased risk of malignancy other than NMSC (relative risk, 2.82; 95% CI, 1.07-7.44) and of NMSC (relative risk, 3.46; 95% CI, 1.08-11.06).

CONCLUSIONS

In patients with CD, the incidence of malignancy with adalimumab monotherapy was not greater than that of the general population. Co-administration of immunomodulator therapy and adalimumab was associated with an increased risk of NMSC and other cancers.

Immune-mediated inflammatory reactions and tumors as skin side effects of inflammatory bowel disease therapy

All drugs currently used for treating patients with inflammatory bowel disease (IBD - including Crohn's disease and ulcerative colitis) have the potential to induce skin lesions ranging from mild eruptions to more serious and widespread clinical presentations. The number of cutaneous adverse reactions due to IBD therapies is progressively increasing and the most frequently involved drugs are thiopurines and biologics like tumor necrosis factor (TNF)-α antagonists. The main drug-induced cutaneous manifestations are non-melanoma skin cancer (NMSC), notably basal cell and squamous cell carcinomas, and viral skin infections for thiopurines and psoriasiform, eczematoid and lichenoid eruptions as well as skin infections and cutaneous lupus erythematosus for biologics. Cutaneous manifestations should be promptly recognized and correctly diagnosed in order to quickly establish an adequate therapy. The main treatment for NMSC is surgical excision whereas the management of immune-mediated inflammatory skin reactions varies from topical therapy for mild presentations to the shift to another drug alone or in combination with corticosteroids for extensive eruptions.

Review article: dermatological complications of immunosuppressive and anti-TNF therapy in inflammatory bowel disease

BACKGROUND

With the expanding list of medications available to treat patients with inflammatory bowel disease (IBD), it is important to recognise adverse events, including those involving the skin. Dermatological adverse events may be confused with extra-intestinal manifestations of IBD.

AIM

To review drug-related dermatological manifestations associated with immunosuppressive and anti-tumour necrosis factor (anti-TNF) therapy.

METHODS

The literature was searched on PubMed for dermatological adverse events in IBD.

RESULTS

Present thiopurine exposure was associated with a 5.9-fold [95% confidence interval (CI), 2.1-16.4] increased risk of developing non-melanoma skin cancer (NMSC). The peak incidence is highest in Caucasians over the age of 65 years with crude incidence rates of 4.0 and 5.7/1000 patient-years for present and previous use. In anti-TNF-exposed subjects, drug-induced lupus was reported in 1% of the cases and a psoriatic rash in up to 3% of the cases. Anti-TNF monotherapy increases the risk of NMSC ~2-fold to a rate of 0.5 cases per 1000 person-years. Cutaneous lymphomas have been rarely reported in subjects on thiopurine or anti-TNF drug monotherapy. Combination therapy seems to have an additive effect on the risk of developing NMSC and lymphoma.

CONCLUSIONS

Physicians need to be aware of the wide spectrum of dermatological complications of immunosuppressive and anti-TNF therapy in IBD, especially psoriasis and non-melanoma skin cancer. Vigilance and regular screening for non-melanoma skin cancer is recommended. Case discussions between gastroenterologists and dermatologists should be undertaken to best manage dermatological adverse events.

Use of azathioprine and the risk of cancer in inflammatory bowel disease

Increased risks of lymphoma and skin cancer associated with thiopurine use among patients with inflammatory bowel disease have been shown, but data on the overall cancer risk are limited. We conducted a historical cohort study of 45,986 patients with inflammatory bowel disease (of whom, 5,197 (11%) used azathioprine) in Denmark from 1997 to 2008. We linked registry data on filled drug prescriptions, cancer diagnoses, and covariates and compared rates of overall incident cancer and cancer subgroups between users and nonusers of azathioprine, adjusting for propensity scores. During a median 7.9 (interquartile range: 3.5-12.0) person-years of follow-up, 2,596 incident cases of cancer were detected. Azathioprine use was associated with an increased risk of overall cancer (rate ratio = 1.41, 95% confidence interval: 1.15, 1.74), whereas former use of azathioprine (rate ratio = 1.02, 95% confidence interval: 0.83, 1.25) or increasing cumulative received doses (increase in rate ratio per 365 additional defined daily doses = 1.06, 95% confidence interval: 0.89, 1.27) were not. In subgroup analyses, azathioprine use was associated with increased risk of lymphoid tissue cancer (rate ratio = 2.40, 95% confidence interval: 1.13, 5.11) and urinary tract cancer (rate ratio = 2.84, 95% confidence interval: 1.24, 6.51). In conclusion, azathioprine use was associated with an increased risk of overall cancer in patients with inflammatory bowel disease, although these data cannot establish causality.

The burden of inflammatory bowel disease in Europe

Inflammatory bowel diseases (IBD) are chronic disabling gastrointestinal disorders impacting every aspect of the affected individual's life and account for substantial costs to the health care system and society. New epidemiological data suggest that the incidence and prevalence of the diseases are increasing and medical therapy and disease management have changed significantly in the last decade. An estimated 2.5-3 million people in Europe are affected by IBD, with a direct healthcare cost of 4.6-5.6 bn Euros/year. Therefore, the aim of this review is to describe the burden of IBD in Europe by discussing the latest epidemiological data, the disease course and risk for surgery and hospitalization, mortality and cancer risks, as well as the economic aspects, patients' disability and work impairment.

Oral squamous cell carcinoma in a Crohn's disease patient taking azathioprine: case report and review of the literature

Thiopurines are widely used for remission maintenance and post-operative recurrence prevention in Crohn's disease. The increased risk of cancer in transplant recipients on azathioprine is well recognized and there are concerns that this may also be true for inflammatory bowel disease patients. We report a case of a 33-year-old Caucasian woman with Crohn's disease treated with azathioprine for 9 years who developed an ulcerated lesion at the right superior retromolar trigone. Biopsy specimen revealed a squamous cell carcinoma.

Increased risk of nonmelanoma skin cancers among individuals with inflammatory bowel disease

BACKGROUND & AIMS

There are limited data on the risk of nonmelanoma skin cancer (NMSC) among individuals with inflammatory bowel disease (IBD), including those with or without exposure to immunosuppressant medications.

METHODS

Individuals with IBD (n = 9618) were identified from the University of Manitoba IBD Epidemiology Database and matched with randomly selected controls (n = 91,378) based on age, sex, and postal area of residence on the date of IBD diagnosis (index date). Groups were followed up from the index date until a diagnosis of any invasive cancer (including NMSC), death, migration from the province, or the end of the study (December 31, 2009), whichever came first. Cox regression analysis was performed to calculate the relative risk of NMSC among the individuals with IBD, adjusting for frequency of ambulatory care visits and socioeconomic status.

RESULTS

Of the individuals followed, 1696 were diagnosed with basal cell skin cancer (BCC) and 341 were diagnosed with squamous cell skin cancer (SCC). Individuals with IBD had an increased risk for BCC, compared with controls (hazard ratio, 1.20; 95% confidence interval [CI], 1.03-1.40). Among patients with IBD, use of thiopurines increased the risk of SCC (hazard ratio, 5.40; 95% CI, 2.00-14.56), compared with controls. Use of thiopurines also was associated with SCC in a case-control, nested analysis of individuals with IBD (odds ratio, 20.52; 95% CI, 2.42-173.81).

CONCLUSIONS

The risk of BCC could be increased among individuals with IBD. Use of thiopurines increases the risk of SCC among individuals with IBD.

Increased risk for nonmelanoma skin cancers in patients who receive thiopurines for inflammatory bowel disease

BACKGROUND & AIMS

Patients with inflammatory bowel disease (IBD) who have been exposed to thiopurines might have an increased risk of skin cancer. We assessed this risk among patients in France.

METHODS

We performed a prospective observational cohort study of 19,486 patients with IBD, enrolled from May 2004 to June 2005, who were followed up until December 31, 2007. The incidence of nonmelanoma skin cancer (NMSC) in the general population, used for reference, was determined from the French Network of Cancer Registries.

RESULTS

Before the age of 50 years, the crude incidence rates of NMSC among patients currently receiving or who previously received thiopurines were 0.66/1000 and 0.38/1000 patient-years, respectively; these values were 2.59/1000 and 1.96/1000 patient-years for the age group of 50 to 65 years and 4.04/1000 and 5.70/1000 patient-years for patients older than 65 years. Among patients who had never received thiopurines, the incidence of NMSC was zero before the age of 50 years, 0.60/1000 for the ages of 50 to 65 years, and 0.84/1000 for those older than 65 years. A multivariate Cox regression model stratified by propensity score quintiles showed that ongoing thiopurine treatment (hazard ratio [HR], 5.9; 95% confidence interval [CI], 2.1-16.4; P = .0006) and past thiopurine exposure (HR, 3.9; 95% CI, 1.3-12.1; P = .02) were risk factors for NMSC. They also identified age per 1-year increase as a risk factor for NMSC (HR, 1.08; 95% CI, 1.05-1.11; P < .0001).

CONCLUSIONS

Ongoing and past exposure to thiopurines significantly increases the risk of NMSC in patients with IBD, even before the age of 50 years. These patients should be protected against UV radiation and receive lifelong dermatologic screening.