Prognostic analysis of hidradenocarcinoma: a SEER-based observational study

Hidradenocarcinoma is a rare malignancy of sweat gland differentiation. Published literature has reported that hidradenocarcinoma has a high recurrence and metastasis rate, and the prognosis is extremely poor. However, the sample sizes included in these studies are insufficient, and therefore, the findings are doubtful.

Clinicopathological characteristics and survival data of 289 hidradenocarcinoma patients were extracted from the SEER database (covering 18 registries, 2000-2018) released in July 2021. The distribution of clinicopathological characteristics was compared using the Pearson chi-square test. Overall survival (OS) and cancer-specific survival (CSS) were analysed using the log-rank test and univariate analysis.

The primary site of hidradenocarcinoma in 121 patients was located in the head and neck, accounting for 41.9%, and the others were located in the trunk and limbs. For hidradenocarcinoma, the mean OS and CSS were 164 months and 165.9 months, respectively; the 10-year OS rate and CSS rate were 60.2% and 90.5%, respectively. Survival analysis showed that the primary site, sex, age, race, histologic grade, stage, and surgery are not associated with hidradenocarcinoma patients' OS or CSS. For head and neck hidradenocarcinoma or trunk and limbs hidradenocarcinoma, sex, age, race, histologic grade, AJCC stage, and primary site surgery are still not related to prognosis. Tumour size is correlated with patients' OS rather than CSS.

Hidradenocarcinoma is a malignant tumour with a good prognosis, which is different from previous views. Tumour size is inversely proportional to patients' overall survival time affecting the OS and CSS of patients. Improving health awareness, initial histological examination and timely surgery are the keys to improving the prognosis.