1151P - Characteristics and treatment outcomes in cutaneous adnexal carcinomas

Background

Cutaneous adnexal tumors comprise a heterogenous group of both benign and malignant tumors evolving from the four primary adnexal structures. Malignant adnexal tumors encompass a variety of histologic subtypes with varying clinical presentation. Due to the rarity of these conditions, incidence and prevalence is not well understood. In a retrospective analysis, estimated five-year Overall Survival (OS) and Disease-Free Survival (DFS) were estimated at 73% and 98%, respectively. There is a paucity of data surrounding the preferred clinical management of cutaneous adnexal tumors due to the rarity of these entities.

Methods

Patients with malignant adnexal tumors were identified using the National Cancer Database (NCDB). We examined demographic, clinicopathologic, and treatment information. Excluded from our cohort were patients with metastatic or unknown disease stage, positive or unknown margin status, unknown radiation and/or chemotherapy status, and unknown vital status. Chi-square analyses were used to assess differences across sebaceous versus non-sebaceous histologies. Multivariable Cox proportional hazard models were used to evaluate the effects of treatment modalities on overall survival after controlling for relevant covariates (age, race, and stage).

Results

3,694 patients were included in the final analysis. The most prevalent malignant cutaneous adnexal tumor included sebaceous carcinoma (n=1699, 46%), eccrine porocarcinoma (n = 568, 15.4%), and skin appendage carcinoma (n =415, 11.2%). In patients with fully resected cutaneous adnexal tumors with negative surgical margins, multivariable results showed that receipt of adjuvant radiation was associated with statistically significantly longer survival compared to not receiving radiation (HR .76 (95%CI 0.61 – 0.96)). Non-sebaceous histology was also associated with longer survival than sebaceous histology (HR 0.78 (95% CI 0.69 – 0.88)). After stratifying by histologic groups, adjuvant radiation was associated with longer overall survival in sebaceous carcinoma (HR 0.62 (95% CI 0.42 – 0.92)), while receipt of adjuvant radiation in non-sebaceous histology groups was not associated with overall survival (HR 0.85 (95% CI 0.65 – 1.13)). Use of adjuvant chemotherapy following R0 resection was not associated with overall survival in the sebaceous group, while in the non-sebaceous group, chemotherapy was associated with shorter overall survival (HR 3.92 (95% CI 1.94 – 7.92)).

Conclusions

Acknowledging the limitations of a retrospective evaluation of real-world data, there does not appear to be a benefit for adjuvant chemotherapy after R0 resection in cutaneous adnexal carcinomas. Alternatively, omission of adjuvant radiotherapy was associated with an increased risk of mortality.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.