It is hypothesized that cisplatin-based chemotherapy (CBCT) reduces the occurrence of metachronous contralateral (second) germ cell testicular cancer (TC). However, studies including treatment details are lacking. The aim of this study was to assess the second TC risk, emphasizing the impact of previous TC treatment.
Based on the Cancer Registry of Norway, 5,620 men were diagnosed with first TC between 1980 and 2009. Treatment data regarding TC were retrieved from medical records. Cumulative incidences of second TC were estimated, and standardized incidence ratios were calculated. The effect of treatment intensity was investigated using Cox proportional hazard regression.
Median follow-up was 18.0 years, during which 218 men were diagnosed with a second TC after median 6.2 years. Overall, the 20-year crude cumulative incidence was 4.0% (95% CI, 3.5 to 4.6), with lower incidence after chemotherapy (CT) (3.2%; 95% CI, 2.5 to 4.0) than after surgery only (5.4%; 95% CI, 4.2 to 6.8). The second TC incidence was also lower for those age ≥ 30 years (2.8%; 95% CI, 2.3 to 3.4) at first TC diagnosis than those age < 30 years (6.0%; 95% CI, 5.0 to 7.1). Overall, the second TC risk was 13-fold higher compared with the risk of developing TC in the general male population (standardized incidence ratio, 13.1; 95% CI, 11.5 to 15.0). With surgery only as reference, treatment with CT significantly reduced the second TC risk (hazard ratio [HR], 0.55). For each additional CBCT cycle administered, the second TC risk decreased significantly after three, four, and more than four cycles (HRs, 0.53, 0.41, and 0.21, respectively).
Age at first TC diagnosis and treatment intensity influenced the second TC risk, with significantly reduced risks after more than two CBCT cycles.
Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 2020 Dec 23 [Epub ahead of print]
Ragnhild Hellesnes, Tor Åge Myklebust, Roy M Bremnes, Ása Karlsdottir, Øivind Kvammen, Helene F S Negaard, Torgrim Tandstad, Tom Wilsgaard, Sophie D Fosså, Hege S Haugnes
Department of Oncology, University Hospital of North Norway, Tromsø, Norway., Department of Research and Innovation, Møre and Romsdal Hospital Trust, Ålesund, Norway., Department of Oncology, Haukeland University Hospital, Bergen, Norway., Department of Oncology, Ålesund Hospital, Ålesund, Norway., Department of Oncology, Oslo University Hospital, Oslo, Norway., The Cancer Clinic, St. Olav's University Hospital, Trondheim, Norway., Department of Community Medicine, UiT, The Arctic University of Norway, Tromsø, Norway., Department of Registration, Cancer Registry of Norway, Oslo, Norway.