title: Cisplatin-based chemotherapy changes the incidence of bilateral testicular cancer.
abstract: BACKGROUND
  The introduction of cisplatin-based chemotherapy has remarkably increased the survival of testicular cancer patients. With this success, the concern for a contralateral testicular tumor has increased. The aim of this study was to investigate whether the risk for contralateral testicular tumor development was influenced by cisplatin-based chemotherapy.
  
  
  METHODS
  The incidence of a contralateral testicular tumor among 365 consecutive patients with a nonseminoma testicular tumor, diagnosed in the period 1980 and 1995, was established and related to previous therapy.
  
  
  RESULTS
  Eleven of 365 men (3%) developed a contralateral testicular tumor. After a total of 2403 person-years at risk, 4 of 225 chemotherapy-treated patients (1.8%) developed a contralateral testicular tumor, and 7 of 140 patients (5%) treated with orchidectomy alone developed a contralateral tumor. In comparison to this surveillance subgroup, patients previously treated with chemotherapy have a relative risk of 0.30 to develop a second testicular tumor.
  
  
  CONCLUSIONS
  In Dutch men with a nonseminoma testicular tumor, the incidence of a contralateral testicular tumor is 3%, which is 60-fold the expected incidence rate of testicular cancer. A three times lower incidence rate of a contralateral testicular tumor was found in the chemotherapy subgroup compared with those on surveillance. This supports the hypothesis that cisplatin-based chemotherapy may eradicate carcinoma in situ or early testicular cancer.
authors.affiliation: Department of Surgical Oncology, University Hospital, Groningen, The Netherlands.
authors.forename: J P
authors.initials: JP
authors.lastname: van Basten
authors.forename: H J
authors.initials: HJ
authors.lastname: Hoekstra
authors.forename: M F
authors.initials: MF
authors.lastname: van Driel
authors.forename: D T
authors.initials: DT
authors.lastname: Sleijfer
authors.forename: J H
authors.initials: JH
authors.lastname: Droste
authors.forename: H
authors.initials: H
authors.lastname: Schraffordt Koops
mesh_terms: D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001761:Bleomycin / Q000008:administration & dosage; D002945:Cisplatin / Q000008:administration & dosage; D005047:Etoposide / Q000008:administration & dosage; D007839:Functional Laterality; D006801:Humans; D008297:Male; D016609:Neoplasms, Second Primary / Q000473:pathology / Q000517:prevention & control*; D013736:Testicular Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000517:prevention & control* / Q000601:surgery
chemical_list: D001761:Bleomycin; D005047:Etoposide; D002945:Cisplatin