title: A new indication of sildenafil in medicine: hypoxic cell sensitizer for penile cancer.
abstract: OBJECTIVE
  To evaluate the feasibility and results of sildenafil used as radiosensitizer by causing penile vasodilatation and reducing tumor hypoxia in radical radiotherapy for penile cancer.
  
  
  METHODS
  Three men with histopathologic diagnosis of squamous carcinoma of penis were treated with radical external radiotherapy with concomitant sildenafil. Acute and late adverse events were noted according to RTOG toxicity criteria. Response to radiotherapy, as well as disease-free and overall survivals, was evaluated.
  
  
  RESULTS
  All three patients achieved tumescence, completed the treatment and achieved complete response. One patient had recurrence at 10 months and died of the disease after 23 months from starting the treatment. Other two patients are disease-free and alive at 48 and 53 months respectively. No excess acute or late adverse event was observed.
  
  
  CONCLUSIONS
  Sildenafil may act as radiosensitizer by causing penile vasodilatation and reducing hypoxia. Larger controlled studies are required to validate the hypothesis.
authors.affiliation: Department of Radiation Oncology, Nanavati Hospital, Mumbai, India. nagrajh@vsnl.net
authors.forename: Nagraj G
authors.initials: NG
authors.lastname: Huilgol
authors.forename: Amit
authors.initials: A
authors.lastname: Jain
mesh_terms: D000328:Adult; D000369:Aged, 80 and over; D002277:Carcinoma / Q000188:drug therapy* / Q000532:radiotherapy; D015687:Cell Hypoxia / Q000187:drug effects*; D003131:Combined Modality Therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D010412:Penile Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy; D010726:Phosphodiesterase Inhibitors / Q000627:therapeutic use*; D010865:Pilot Projects; D010879:Piperazines / Q000627:therapeutic use*; D011687:Purines / Q000627:therapeutic use; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000627:therapeutic use*
chemical_list: D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate