Tumour size, age predict survival in dermatofibrosarcoma protuberans

The incidence of dermatofibrosarcoma protuberans (DFSP) is two times higher among Black than White individuals, reports a study. 

Moreover, the risk of DFSP metastasis is significantly higher in patients with larger tumour size and those with tumours located on their head and neck or genitalia.

A team of investigators analysed the incidence rate, overall and DFSP-specific survival outcomes for primary DFSP tumours contained in the Surveillance, Epidemiology, and End Results (SEER) registry using quasi-Poisson regression, Cox, and competing risk analyses.

The incidence rate of DFSP was 6.25 (95 percent confidence interval [CI], 5.93–6.57) cases per million person-years. Of note, a significantly higher incidence was seen among Black than White patients (8.74 vs 4.53 cases per million person-years).

DFSP with tumour size ≥3 cm (odds ratio [OR], 2.24, 95 percent CI, 1.62–3.12; p<0.001) and tumours located on the head and neck (OR, 4.88, 95 percent CI, 3.31–7.18; p<0.001) and genitalia (OR, 3.16, 95 percent CI, 1.17–8.52; p=0.023) contributed to a significantly elevated risk of metastasis. On the other hand, higher socioeconomic status correlated with a significantly lower metastasis risk.

In addition, larger tumour size, regardless of location, and older age (≥60 years) significantly predicted worse overall and cancer-specific survival.

“Larger tumour size (≥ 3 cm), regardless of location, and age (≥60 years) are the most important prognostic indicators of survival,” the investigators said. 

This study was limited by the retrospective design of SEER.