Extramammary Paget's disease (EMPD) is a rare intraepithelial adenocarcinoma affecting the genitals and axillary regions. As metastasis of these tumours is itself rare, solid disease management strategies have not been established. Serum carcinoembryonic antigen (CEA) and cytokeratin 19 fragment 21‐1 (CYFRA 21‐1) levels have been identified as candidate biomarkers for tumour progression in EMPD; however, neither the accuracy of, nor correlation between, these markers have been examined in EMPD patients.
Although carcinoembryonic antigen (CEA) and cytokeratin 19 fragment (CYFRA) are useful marker for extramammary Paget's disease (EMPD), the serum CEA and CYFRA levels are not elevated in most EMPD patients without metastasis. Therefore, further useful biomarkers are needed for the detection of EMPD including early lesions. Cell‐free DNA (cfDNA) has attracted attention as an indicator of clinical conditions in several cancers, and we studied the clinical implications of cfDNA for EMPD. The serum cfDNA levels were significantly elevated in EMPD patients with or without metastasis compared to those in healthy controls. And serum cfDNA was a better diagnostic marker for the presence of EMPD compared to serum CYFRA. Moreover, the post‐operative serum cfDNA levels were significantly lower than those from the pre‐operative samples, and the change in serum cfDNA levels reflected the clinical courses of EMPD patients treated with chemotherapy. Taken together, serum cfDNA levels may be useful marker for the diagnosis and disease progression in EMPD.
Extramammary Paget disease (EMPD) is a rare dermatologic condition that frequently presents in areas where apocrine sweat glands are abundant, most commonly the vulva, although perineal, scrotal, perianal, and penile skin may also be affected. Lesions clinically present as erythematous, well-demarcated plaques that may become erosive, ulcerated, scaly, or eczematous. Extramammary Paget disease has a female predominance and usually occurs in the sixth to eighth decades of life. Professionals disagree about many aspects of EMPD, for example, the prevalence of concurrent vulvar adenocarcinoma or invasive EMPD, association with regional and distant cancers, and recurrence rates following surgical excision. Early recognition is imperative because the diagnosis is frequently delayed and there is a high incidence of associated invasive disease.
Cytokeratin 19 fragment 21-1 (CYFRA 21-1) has been used as a tumor marker for several malignancies. However, to date, no studies have assessed whether CYFRA 21-1 could be a useful marker for extramammary Paget's disease (EMPD). The present study aimed to evaluate the significance of CYFRA 21-1 as a serum tumor marker for EMPD progression. Concentrations of serum CYFRA 21-1 and carcinoembryonic antigen (CEA) in 13 cases of EMPD were measured prior to undergoing treatment at Sapporo Medical University Hospital from January 2014 to May 2016. Four of the 13 patients had lymph node metastases at diagnosis, but none had distant metastases. Immunohistochemistry indicated that all 13 primary tumors and four metastatic tumors in lymph nodes were positive for cytokeratin 19. Although none of the 13 patients showed high serum CEA levels, six patients (46.2%) had elevated serum CYFRA 21-1. Furthermore, CYFRA 21-1 was reduced in association with post-treatment tumor reduction in all six patients. Among these six patients, four developed recurrence and metastasis during the follow-up period. CYFRA 21-1 was re-elevated in all four of these patients; however, serum CEA was elevated only in the patient with distant metastasis. These results suggest that CYFRA 21-1 is more sensitive compared with CEA, and can be useful as a tumor marker for evaluating tumor progression and treatment efficacy in patients with EMPD.