Electrochemotherapy with cisplatin or bleomycin in head and neck squamous cell carcinoma: Improved effectiveness of cisplatin in HPV-positive tumors.

Human papillomavirus (HPV) is an important etiological factor in head and neck squamous cell carcinomas (SCCs). Standard treatment of HPV-positive tumors with platinum-based radio(chemo)therapy results in a better outcome than in HPV-negative tumors. Electrochemotherapy is becoming an increasingly recognized mode of treatment in different cancers; thus, its use in the management of head and neck SCC is of considerable interest. However, response to electrochemotherapy according to HPV status of the tumors has not been evaluated yet. Thus, our aim was to compare the effect of electrochemotherapy with cisplatin or bleomycin between HPV-negative and HPV-positive human pharyngeal SCC derived cell lines and tumor models. HPV-positive cells and tumors were found to be more sensitive to electrochemotherapy with cisplatin than HPV-negative ones, whereas sensitivity to electrochemotherapy with bleomycin was similar irrespective of the HPV status. The higher sensitivity of HPV-positive cells and tumors to electrochemotherapy with cisplatin is likely due to the higher level and slower repair of DNA damage. In HPV-negative tumors, a higher number of complete responses was recorded after bleomycin-based rather than cisplatin-based electrochemotherapy, while in HPV-positive tumors electrochemotherapy with cisplatin was more effective.