How are patients with skin of color uniquely affected by dermatofibrosarcoma protuberans?
Clinical Applications
By Kathryn Schwarzenberger, MD, FAAD, June 1, 2025
In this month’s Clinical Applications column, Physician Editor Kathryn Schwarzenberger, MD, FAAD, talks with Travis Blalock, MD, MBA, FAAD, about his recent JAAD paper, ‘The epidemiology of dermatofibrosarcoma protuberans incidence, metastasis, and death among various population groups: A Surveillance, Epidemiology, and End Results database analysis.’
DermWorld: Your paper measured the incidence, metastasis, and survival outcomes of dermatofibrosarcoma protuberans (DFSP). Why did you choose to study this topic?
DermWorld: For those who haven’t read your paper, how did you go about assessing and measuring the incidence rates, metastasis, and survival outcomes?
Dr. Blalock: We are so fortunate to have such great data repositories in this country and we were able to access and review the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) registry. We reviewed the data from 2000 to 2018, measuring incidence rates based on those 18 population-based registries. For metastatic disease, we were able to characterize DFSPs based on whether the disease was localized, regional, or distant. To delve deeper, we evaluated various standard patient characteristics alongside socioeconomic status (SES), utilizing the SEER 17 census tract-level SES and rurality database for the years 2006-2018. Additionally, we leveraged the same database to analyze survival outcomes, including both DFSP-specific cancer survival and overall survival rates.
DermWorld: What were your findings?
Dr. Blalock: Some of our findings aligned with expectations and reinforced existing data. For instance, our analysis confirmed that Black patients have a higher incidence of DFSP, with a rate of 8.74 cases per million person-years, compared to white patients, whose incidence is 4.53 cases per million person-years. Notably, the incidence of DFSP remained consistent over the 18 years of data reviewed, and the rates of DFSP were similar between men and women. We did find that the risk of DFSP metastasis is markedly increased for patients with tumors that are larger than 3 cm as well as patients who had cancers on the head, neck, or genitalia. Finally, we found that patients who had surgery had better overall survival.
DermWorld Insights & Inquiries
DermWorld: In addition to racial differences regarding DFSP incidence, did any specific socioeconomic or demographic factors consistently predict higher disease severity?
Dr. Blalock: I noted earlier the two-fold higher DFSP incidence in Black patients than white patients. Interestingly, something happens in the data, which indicates that after the age of 80, Black patients had the lowest mean incidence of DFSP. Although we found a difference between incidences, there was no difference in the overall survival between Black and white patients. One notable finding in our data was the significantly improved overall survival for Hispanic patients. Beyond racial differences, we also found that patients living in higher socioeconomic quintiles had lower risk of metastatic disease as compared to those in the lowest socioeconomic quintile. While it’s not clear why, some might assume an access-related factor that impacts this risk. While there may be many different factors that may help us predict higher disease severity, for our specific model, demographic factors explained 45% of variation vis-à-vis DFSP incidence.
DermWorld: You and your colleagues conducted a subgroup analysis comparing Mohs micrographic surgery to wide surgical excision. Did you identify any significant differences between the treatments in terms of recurrence rates or cancer-specific survival?
Dr. Blalock: Multivariable Cox survival analysis for overall survival showed Mohs to have an improved overall survival as compared with wide local excision. However, this difference was not significant. So, with our analysis, no survival benefit was found for Mohs micrographic surgery. There are several studies with data indicating lower recurrence rates with Mohs micrographic surgery compared with wide local excision. However, our examination of the SEER registry could not assess this because data on locoregional recurrence was not collected by SEER. Thus, we believe that further investigation is warranted to characterize the benefit of Mohs surgery for DFSP treatment.
DermWorld: What implications do these findings have for health care policy?
Dr. Blalock: These findings reinforce the vital commitment dermatologists have to detecting disease in all patients. Our data emphasizes that patients with skin of color are uniquely impacted by DFSP and tend to experience worse outcomes as they age, at least until the age of 80. Whether this will lead to changes in health care policy remains uncertain. However, if our goal is to detect DFSP at smaller sizes and identify it in higher-risk areas such as the head, neck, and genitalia, we must approach this task with intentionality. This includes carefully examining these specific areas and paying close attention to patients at higher risk. As Arthur Conan Doyle aptly stated, “The world is full of obvious things which nobody by any chance ever observes.” Perhaps our findings serve as a valuable reminder to actively screen and thoroughly examine patients for this challenging tumor.
Travis W. Blalock, MD, MBA, FAAD, is director of dermatologic surgery, Mohs micrographic surgery, and cutaneous oncology for the department of dermatology at Emory. He is currently an associate professor of dermatology at the Emory University School of Medicine. His paper appeared in the Journal of the American Academy of Dermatology.
Dr. Blalock does not have any relevant financial or commercial conflicts of interest.
Disclaimer: The views and opinions expressed in this article do not necessarily reflect those of DermWorld.
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