Successful treatment of bilateral multiple lymph node metastases in extramammary Paget's disease with surgery and sequential chemotherapy of S‐1 and docetaxel

Dear Editor, Patients with bilateral lymph node metastases of extramammary Paget’s disease (EMPD) have a very poor prognosis, and the management of enlarged regional lymph nodes is controversial. We successfully treated a 77-year-old man with bilateral multiple lymph node metastases of EMPD with surgery and sequential chemotherapy of S-1, containing a 5-fluorouracil derivative (Taiho Pharmaceutical, Tokyo, Japan) and docetaxel (TXT). He had a medical history of autoimmune hepatitis and received a patch graft surgery to bilateral inguinal hernia 3 months before. He had noticed a gradually enlarging erythema around the base of the penis for 1 year. Physical examination revealed erythema with irregularly shaped erosion, 5.0 cm 9 3.5 cm in diameter, on the base of the penis (Fig. 1a). The serum carcinoembryonic antigen (CEA) level was 140.1 ng/mL (normal range, <4). Computed tomography (CT) disclosed neither lymphadenopathy nor signs of distant metastasis. We performed local excision with a wide margin and sentinel lymph node biopsy. Histology revealed Paget cells in the epidermis and dermis, with lymphatic invasion (Fig. 1b). The sentinel lymph nodes were metastasis-positive (right, 2/2; left, 3/3). Accordingly, following the initial surgery, we performed bilateral inguinal lymph node dissection. As a result, tumor cells were found to involve 28 of 31 (right, 12/12; left, 16/19) dissected lymph nodes. Post-surgery, CT revealed left external iliac lymph node swelling (Fig. 1c), and elevated serum CEA levels (161.6 ng/mL) were observed. Because the patient preferred aggressive treatment, we attempted chemotherapy with S-1 and TXT, referring to the report by Matsushita et al. We started delivery of S-1 (100 mg/m per day for 14 days consecutively, first cycle) and TXT (60 mg/m per day on day 1) at 2-week intervals in an outpatient clinic. The patient developed grade 4 neutrophil count decrease, grade 3 white blood cell decrease and grade 2 anorexia (Common Terminology Criteria for Adverse Events version 4.0). We immediately administrated granulocyte colony-stimulating factor and he passed without any side-effect afterwards. We consequently decreased the S-1 and TXT doses to 60 and 40 mg/m, respectively, after the second cycle. As a result, he could complete the therapy without any major adverse event after the second cycle. After the third cycle, the swollen external iliac lymph nodes were reduced from 12 to 6 mm upon CT (Fig. 1d), and the serum CEA level was decreased to 40.6 ng/mL. One year post-surgery, he remains alive and disease-free. In this case, there was no sign of lymph node and distant metastasis in imaging findings at initial therapy. We performed inguinal dissection in hope of the possibility of complete resection with a plan that we perform sequential chemotherapy, if metastasis has occurred. In addition, the efficacy of taxanes and oral S-1 has been reported in recent years. This case demonstrates the excellent effect of surgery and sequential S-1/TXT chemotherapy in a patient with multiple lymph node metastases of EMPD. This regimen has the advantage that it can be carried out in an outpatient clinic, and improvement of the prognosis of advanced EMPD patients can be expected. (a)