Association Between Topical Calcineurin Inhibitor Use and Keratinocyte Carcinoma Risk Among Adults With Atopic Dermatitis.

Importance: Topical calcineurin inhibitors (TCIs), primarily used to treat atopic dermatitis (AD), carry a black box label warning users about the potential for increased skin cancer risk. The risk associated with keratinocyte carcinoma (KC), the most common cancer, defined as basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), remains poorly defined because findings from large-scale postmarketing surveillance studies have not been reported. Objectives: To examine KC risk overall and by subtype (BCC and SCC) among adults with AD exposed to TCIs compared with those exposed to topical corticosteroids (primary comparator group) and those unexposed to TCIs or topical corticosteroids (alternative comparator group) as well as alterations in risk with TCI dose, frequency, and duration of exposure. Design, Setting, and Participants: A retrospective cohort study was conducted at Kaiser Permanente Northern California, a large, integrated health care delivery system, of adults 40 years or older (n = 93 746) with a physician-rendered diagnosis of AD or dermatitis. Patients who were diagnosed from January 1, 2002, to December 31, 2013, were included, with follow-up through December 31, 2017. Data analysis was conducted from June 1, 2016, to October 1, 2018. Exposures: Time-varying pharmacy-dispensed TCI exposure (n = 7033) over the study period was compared with topical corticosteroids (n = 73 674) and no TCI or topical corticosteroid exposure (n = 46 141). Main Outcomes and Measures: Electronic pathologic testing-validated incident KCs (n = 7744). Results: Among a cohort of 93 746 members, the mean (SD) age was 58.5 (12.7) years, and 55 023 patients (58.7%) were women. Multivariable Cox proportional hazards regression revealed no association between TCI exposure and KC risk (adjusted hazard ratio [aHR], 1.02; 95% CI, 0.93-1.13) compared with topical corticosteroid exposure. Similarly, there were no significant differences in BCC risk (aHR, 1.01; 95% CI, 0.90-1.14, TCI vs topical corticosteroids) or SCC risk (aHR, 0.94; 95% CI, 0.82-1.08, TCI vs topical corticosteroids). Changing the comparator group to unexposed individuals yielded similar findings (aHR, 1.04; 95% CI, 0.91-1.19, TCI vs unexposed for basal cell carcinoma). There were no associations between TCI dose, frequency, and duration of use and BCC, SCC, or overall KC risk. Conclusions and Relevance: The results of this postmarketing surveillance study of adult health plan members with AD revealed no apparent association between TCI exposure and overall KC, BCC, or SCC risk. Secondary analyses examining dose, frequency, and duration of TCI exposure revealed no associations. These findings suggest that use of TCIs may be safe with respect to KC risk among adults with AD.

Comparative effectiveness of treatment of actinic keratosis with topical fluorouracil and imiquimod in the prevention of keratinocyte carcinoma: A cohort study.

BACKGROUND: The effectiveness of 5-fluorouracil compared with that of imiquimod for preventing keratinocyte carcinoma is unknown. OBJECTIVE: To compare the effectiveness of 5-fluorouracil and that of imiquimod in preventing keratinocyte carcinoma in a real-world practice setting. METHODS: We identified 5700 subjects who filled prescriptions for 5-fluorouracil or imiquimod for treatment of actinic keratosis in 2007. An intention-to-treat analysis controlling for potential confounding variables was used to calculate 2- and 5-year cumulative risk differences for subsequent keratinocyte carcinoma overall and in field-treated areas. RESULTS: 5-Fluorouracil was associated with a statistically significant decreased risk of any keratinocyte carcinoma compared with imiquimod (adjusted hazard ratio [aHR], 0.86; 95% confidence interval [CI], 0.76-0.97), but there were no significant differences in risk by tumor subtype (for squamous cell carcinoma: aHR, 0.89; 95% CI, 0.74-1.07; for basal cell carcinoma: aHR, 0.87; 95% CI, 0.74-1.03) or site-specific keratinocyte carcinoma (aHR, 0.96; 95% CI, 0.81-1.14). There were no significant differences in 2- or 5-year cumulative risk of keratinocyte carcinoma among those treated with 5-fluorouracil versus with imiquimod. LIMITATIONS: Generalizability to other practice settings may be limited. CONCLUSIONS: Whereas 5-fluorouracil was more effective in reducing keratinocyte carcinoma risk overall, we found no differences in the short- or long-term risk of subsequent site-specific keratinocyte carcinoma in a real-world practice setting.

A real-world, community-based cohort study comparing the effectiveness of topical fluorouracil versus topical imiquimod for the treatment of actinic keratosis.

BACKGROUND: The most widely used topical agents for the field-based treatment of multiple actinic keratoses (AKs) are 5-fluorouracil and imiquimod, but their comparative effectiveness has not been assessed in a real-world setting. OBJECTIVE: We compared the effectiveness of 5-fluorouracil and imiquimod in reducing risk for subsequent AKs in a large, integrated health care delivery system in northern California. METHODS: In this cohort study, we identified adult health plan members who had an AK diagnosed in 2007 and who subsequently filled a prescription for 5-fluorouracil or imiquimod (N = 5700). We followed subjects for subsequent AKs identified by the International Classification of Diseases codes and estimated the 2-year (short-term) and 5-year (long-term) differences in cumulative risk while controlling for potential confounding by pretreatment variables. RESULTS: 5-Fluorouracil reduced the short-term incidence of subsequent AKs (cumulative risk difference -4.54% [95% confidence interval, -7.91% to -1.17%]), but there was no statistically significant evidence of a long-term decreased risk (cumulative risk difference -1.43% [95% confidence interval, -3.43% to 0.05%]) compared with that with imiquimod. LIMITATIONS: This is a retrospective study with limited ascertainment of all relevant potential confounding variables. CONCLUSION: We found that 5-fluorouracil appeared to be significantly more effective than imiquimod in the short-term, but not long-term, prevention of subsequent AKs.

CD8+ lymphocyte intratumoral infiltration as a stage-independent predictor of Merkel cell carcinoma survival: a population-based study.

OBJECTIVES: Intratumoral CD8+ lymphocytes (IT-CD8s) have shown promise as a prognostic indicator for Merkel cell carcinoma (MCC). We tested whether IT-CD8s predict survival among a population-based MCC cohort. METHODS: One hundred thirty-seven MCC cases that had not previously been analyzed for IT-CD8s were studied. RESULTS: Three-year MCC-specific survival rates were 56%, 72%, and 100% for patients with absent (n = 46), low (n = 85), and moderate or strong (n = 6) IT-CD8s, respectively. Increased IT-CD8s were associated with improved MCC-specific survival in a multivariate competing risk-regression analysis including stage, age, and sex (hazard ratio [HR] = 0.5; 95% confidence interval [CI] = 0.3-0.9). Although a similar trend was observed for overall survival, statistical significance was not reached (HR = 0.8; 95% CI = 0.6-1.0), likely because of the high rate of non-MCC deaths among older patients. CONCLUSIONS: This study of prospectively captured MCC cases supports the concept that cellular immunity is important in MCC outcome and that CD8+ lymphocyte infiltration adds prognostic information to conventional staging.

Effect of host, tumor, diagnostic, and treatment variables on outcomes in a large cohort with Merkel cell carcinoma.

IMPORTANCE: Merkel cell carcinoma (MCC) is a rare, aggressive, neuroendocrine-derived skin cancer with high rates of recurrence and associated mortality. Few published studies have used comprehensive patient data and long-term follow-up to examine factors that predict MCC outcomes. OBJECTIVE: To characterize MCC in a large defined-population cohort and analyze predictors of disease recurrence and survival. SETTING, DESIGN, AND PARTICIPANTS: Retrospective cohort study of 218 patients with MCC from the cancer registry of Kaiser Permanente Northern California, a large integrated health care delivery system. Patients were diagnosed as having MCC and followed up from January 1, 1995, through December 31, 2009. We examined host (age, sex, race, and immunosuppression), tumor (anatomic site, size, and extent), diagnostic (results of imaging and pathologic nodal evaluation), and treatment (surgery, radiation therapy, and chemotherapy) variables for their association with MCC outcomes. EXPOSURE: Host, tumor, diagnostic, and treatment factors. MAIN OUTCOMES AND MEASURES: Recurrence (locoregional and distant) of MCC and patient survival (overall and MCC specific). RESULTS: We estimated adjusted hazard ratios (AHRs) and 95% CIs for outcomes using Cox proportional hazards regression models. After adjustment for host, tumor, diagnostic, and treatment variables, tumor extent (categorized as local, regional, and distant) remained significantly associated with all outcomes. Immunosuppression was associated with higher MCC-specific mortality (AHR, 4.9 [95% CI, 1.7-14.4]), and an unknown primary site was associated with a lower risk for distant metastasis (0.1 [0.0-0.7]) and improved survival (0.4 [0.2-0.9]). Pathological nodal evaluation was associated with a lower risk for metastasis (AHR, 0.2 [95% CI, 0.0-1.0]) and improved survival. Radiation treatment was associated with a decreased risk for locoregional recurrence (AHR, 0.3 [95% CI, 0.1-0.6]), whereas chemotherapy was not associated with any alteration in outcomes. CONCLUSIONS AND RELEVANCE: Tumor site and extent, results of pathologic nodal evaluation, and the presence of radiation treatment were associated with MCC recurrence. Immunosuppression, tumor extent, and results of pathologic nodal evaluation were associated with MCC-specific survival, whereas chemotherapy was not associated with any outcomes. Our findings may help to inform diagnostic and therapeutic management of MCCs.

Systemic immune suppression predicts diminished Merkel cell carcinoma-specific survival independent of stage.

Merkel cell carcinoma (MCC) is an aggressive cutaneous malignancy linked to a contributory virus (Merkel cell polyomavirus). Multiple epidemiologic studies have established an increased incidence of MCC among persons with systemic immune suppression. Several forms of immune suppression are associated with increased MCC incidence, including hematologic malignancies, HIV/AIDS, and immunosuppressive medications for autoimmune disease or transplant. Indeed, immune-suppressed individuals represent ∼10% of MCC patients, a significant overrepresentation relative to the general population. We hypothesized that immune-suppressed patients may have a poorer MCC-specific prognosis and examined a cohort of 471 patients with a combined follow-up of 1,427 years (median 2.1 years). Immune-suppressed patients (n=41) demonstrated reduced MCC-specific survival (40% at 3 years) compared with patients with no known systemic immune suppression (n=430; 74% MCC-specific survival at 3 years). By competing risk regression analysis, immune suppression was a stage-independent predictor of worsened MCC-specific survival (hazard ratio 3.8, P<0.01). Thus, immune-suppressed individuals have both an increased chance of developing MCC and poorer MCC-specific survival. It may be appropriate to follow these higher-risk individuals more closely, and, when clinically feasible, there may be a benefit of diminishing iatrogenic systemic immune suppression.