Factors associated with time to treatment for Merkel cell carcinoma

Differences in Merkel Cell Carcinoma Presentation and Outcomes Among Racial and Ethnic Groups

Importance

Racial and ethnic differences in skin cancer outcomes are understudied. Delineating these differences in Merkel cell carcinoma (MCC) is needed to better understand this rare disease.

Objective

To determine how MCC presentation and outcomes differ across racial and ethnic groups.

Design, Setting, and Participants

This retrospective cohort study included patients diagnosed with MCC and followed up from 2000 through 2018 in the 18 population-based cancer registries of the National Cancer Institute's Surveillance, Epidemiology, and End Results Program. Patients without follow-up data were excluded. Data analysis occurred from March 12 to November 30, 2022.

Main Outcomes and Measures

A Cox proportional hazards regression was conducted to determine associations between demographic variables (race and ethnicity, age, sex, and income) and clinical variables (stage at diagnosis, primary site, and diagnosis year) with MCC-specific survival.

Results

Of the 9557 patients with MCC identified (6758 [70.7%] aged ≥70 years; 6008 [62.9%] male), 222 (2.3%) were Asian American or Pacific Islander, 146 (1.5%) Black, 541 (5.7%) Hispanic, and 8590 (89.9%) White. Hispanic patients had improved MCC-specific survival compared with White patients (hazard ratio, 0.82; 95% CI, 0.67-0.99; P = .04). Black patients had the lowest MCC-specific survival, but it was not statistically different from White patients (hazard ratio, 1.19; 95% CI, 0.86-1.60; P = .28). Hispanic and Black patients were less likely to present with a primary site of the head and neck than White patients (183 of 541 [33.8%] Hispanic patients and 45 of 146 [30.8%] Black patients vs 3736 of 8590 [43.5%] White patients; P < .001 and P = .002, respectively). Black patients presented more often than White patients with advanced disease at diagnosis (59 of 146 [40.4%] vs 2510 of 8590 [29.2%]; P = .004).

Conclusions and Relevance

In this cohort study, there were differences between racial and ethnic groups in observed MCC outcomes and disease characteristics. Further investigations are warranted into the findings that, compared with White patients, Hispanic patients with MCC had improved outcomes and Black patients did not have worse outcomes despite presenting with more advanced disease.

Challenges documenting racial disparities in Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine skin cancer that predominantly impacts White patients. Overall incidence and the proportion of minority patients with MCC are both rising. In the more common skin cancer, melanoma, racial disparities are well-documented in stage at presentation and patient survival. Whether racial and ethnic disparities exist in MCC remains unclear. The study of MCC disparities is hampered by limitations in data registries, including SEER and NCDB, and an evolving natural history due to the advent of immunotherapy. Published MCC immunotherapy clinical trials consistently reported the racial diversity among enrolled subjects but failed to include patients' ethnicities. Efforts to improve data capture in cancer registries and create multi-institutional clinical databases will allow for more effective study of racial and ethnic disparities in rare cancers like MCC. Such studies are needed to advance policies promoting equity in care.

Patterns of Care and Data Quality in a National Registry of Black and White Patients with Merkel Cell Carcinoma

Merkel Cell Carcinoma (MCC) is a rare cancer most commonly affecting White patients; less is known for Black patients. We aim to report presentation, treatment, and quality of registry data by race with a secondary endpoint of overall survival. We conducted a retrospective cohort analysis between 2006−2017 via the National Cancer Database of Black and White MCC patients with and without known staging information. Multivariable logistic, proportional odds logistic, and baseline category logistic regression models were used for our primary endpoint. Multivariable Cox regression was used to interrogate overall survival. Multiple imputation was used to mitigate missing data bias. 34,503 patients with MCC were included (2566 Black patients). Black patients were younger (median age 52 vs. 72, p < 0.0001), had higher rates of immunosuppression (28% vs. 14%, p = 0.0062), and were more likely to be diagnosed at a higher stage (proportional OR = 1.41, 95% CI 1.25−1.59). No differences were noted by race across receipt of definitive resection (DR), though Black patients did have longer time from diagnosis to DR. Black patients were less likely to receive adjuvant radiation. Black patients were more likely to have missing cancer stage (OR = 1.69, CI 1.52−1.88). Black patients had decreased adjusted risk of mortality (HR 0.73, 0.65−0.81). Given the importance of registry analyses for rare cancers, efforts are needed to ensure complete data coding. Paramount to ensuring equitable access to optimal care for all is the recognition that MCC can occur in Black patients.

Predictors of Time to Definitive Surgery and Survival in Merkel Cell Carcinoma: Analysis of National Cancer Database

BACKGROUND

Effects of delays in treatment for Merkel cell carcinoma (MCC) are not yet fully understood.

OBJECTIVES

To determine the effect of time to treatment initiation (TTI) on mortality in MCC and predictors of TTI itself.

METHODS

Retrospective cohort analysis of the National Cancer Database (NCDB) for cases of MCC from 2004-2016, excluding individuals with Stage IV MCC as surgery is not the preferred treatment for this group.

RESULTS

A total of 12,157 patients (average age:74.4 years, SD:10.9) were included in the study, 7,491(61.6%) were male and 4,666 (38.4%) were female. Risk of higher TTI was seen in Blacks (odds ratio [OR]:1.7, 95% CI:1.2,2.6) and elderly individuals over 70 years (OR:1.7, 95% CI:1.2,2.5). On Kaplan-Meier survival analysis, individuals with TTI <30 days had a significantly longer overall survival than those with TTI >120 days (6.1 vs. 4.8 years, p=0.0002). However, after controlling for clinical and tumor factors in Cox multivariable analysis, no difference in survival was noted for TTI <30 days and TTI >120 days (Hazard Ratio [HR]:0.9, 95% CI:0.8,1.1). Worse outcomes were also associated with increasing age (HR:2.0, 95% CI:1.7,2.5), male sex (HR:1.2, 95% CI:1.2-1.3), higher CDCC (HR:1.4, 95% CI:1.3,1.5), lack of radiation therapy (HR:0.8, 95% CI:0.8-0.9), lack of private insurance (HR:0.7, 95% CI:0.6-1.0), and surgical technique other than Mohs or WLE (HR:1.2, 95% CI:1.2-1.3).

CONCLUSIONS

Although TTI is a useful prognostic metric in isolated survival analysis, its utility declines when controlling for other factors. Age, radiotherapy, type of surgery performed, co-morbidities, tumor size, and lymph node involvement may be important predictors of survival.