Vulvar cancer: Two pathways with different localization and prognosis

Background. Two etiologic pathways for vulvar squamous cell carcinoma (SCC) are described: in a background of lichen sclerosus and/or differentiated vulvar intraepithelial neoplasia and related to high-risk human papillomavirus (HPV) infection with high grade squamous intraepithelial lesion (HSIL) as precursor. The aim was to compare the predilection site and survival of HPV-related to non HPV-related vulvar SCCs. Methods. Data of patients treated for primary vulvar SCC at the Radboudumc between March 1988 and January 2015 were analyzed. All histological specimens were tested for HPV with the SPF10/DEIA/LiPA(25) system assay and p16(INK4a) staining was performed using CINtec (R) histology kit. Vulvar SCCs were considered HPV-related in case of either >25% p16(INK4a) expression and HPV positivity or >25% p16(INK4a) expression and HSIL next to the tumor without HPV positivity. Tumor localization, disease specific survival (DSS), disease free survival (DFS) and overall survival (OS) of patients with HPV-related and non HPV-related vulvar SCC were compared. Results. In total 318 patients were included: 55 (17%) had HPV-related (Group 1) and 263 (83%) had non HPV-related vulvar SCC (Group 2). Tumors in Group 1 were significantly more often located at the perineum compared to Group 2, 30% and 14%, respectively (p = 0.001). The DSS, DFS and OS were significantly better in HPV-related than in non HPV-related vulvar SCC patients. Conclusion. HPV-related vulvar SCCs are more frequently located at the perineum and have a favorable prognosis compared to non HPV-related vulvar SCCs. Both localization and HPV-relation could explain this favorable prognosis. HPV-related vulvar SCC seems to be a separate entity. (C) 2018 Elsevier Inc. All rights reserved.