This study included a population-based cohort of 5,620 men diagnosed with first testicular cancer between 1980-2009, as well as second testicular cancer, who were identified by the Cancer Registry of Norway. Treatment data were based on medical records. Cumulative incidence of metachronous contralateral testicular cancer was estimated, and standardized incidence ratios (SIRs) were calculated to compare the risk to the general population. The effect of treatment intensity on the second testicular cancer risk was investigated using Cox regression:
Over a median follow-up of 16.3 years, there were 218 men diagnosed with a second testicular cancer after a median 6.2 years (IQR 3.3-10.6) from the initial testicular cancer diagnosis. Median time to second testicular cancer was shorter after chemotherapy (5.5 years) than after surgery only (6.6 years). Overall, the 20-year crude cumulative incidence was 4.0% (95% CI 3.5-4.6), with lower incidence after chemotherapy (3.2 %, 95% CI 2.4-3.9) than after surgery only (5.4%, 95% CI 4.4-7.3).
The second testicular cancer incidence was also lower for those ≥30 years (2.8%, 95% CI 2.2-3.4) at first testicular cancer diagnosis than those <30 years (6.0 %, 95% CI 4.9-7.1):
Overall, the risk of a second testicular cancer was 13-fold higher compared with the risk of developing testicular cancer in the general population (SIR 13.3, 95% CI 11.6-15.3). The SIR was lower after chemotherapy (9.1, 95% CI 7.1-11.6) than after surgery only (17.1, 95% CI 13.6-21.7). With surgery only as the referent variable, treatment with chemotherapy significantly reduced the risk of a second testicular cancer (HR 0.52, 95% CI 0.37-0.73). For each cisplatin-based chemotherapy cycle administered, the risk for a second testicular cancer decreased monotonously, with significantly reduced risks after 3 (HR 0.53, 95% CI 0.29-0.97), 4 (HR 0.41, 95% CI 0.25-0.66) and >4 cycles (HR 0.21, 0.07-0.66).
Dr. Hellesnes concluded this presentation on risk of second testicular malignancies with the following summary points:
- The overall 20-year cumulative incidence of a second testicular cancer was 4.0%
- Age at first testicular cancer diagnosis as well as treatment intensity influenced the risk of a second testicular cancer, with a monotonic risk reduction for each additional cisplatin-based chemotherapy cycle administered.
Co-authors: T.Å. Myklebust 2 , Ø. Kvammen 3 , R. Bremnes 4 , Á. Karlsdottir 5 , H.F.S. Negaard 6 , T. Tandstad 7 , T. Wilsgaard 8 , S.D. Fosså 9 , H.S. Sagstuen Haugnes 10
Affiliations: 2 Department of Registration, Cancer Registry of Norway, Oslo, Norway, 3 Department of Oncology, Ålesund Hospital, Ålesund, Norway, 4 Department of Clinical Medicine, UiT The Arctic University, Tromsø, Norway, 5 Department of Oncology, Haukeland University Hospital, Bergen, Norway, 6 Department of Oncology, Oslo University Hospital, Oslo, Norway, 7 The Cancer Clinic, St. Olav´s University Hospital, Trondheim, Norway, 8 Department of Community Medicine, Uit The Arctic University, Tromsø, Norway, 9 National Advisory Unit on Late Effects after Cancer Treatment, Oslo University Hospital Rikshospitalet - Radiumhospitalet, Oslo, Norway 10 Department of Oncology, University Hospital of North Norway, Tromso, Norway
Written by: Zachary Klaassen, MD, MSc, Assistant Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia, Twitter: @zklaassen_md, at the European Society for Medical Oncology Virtual Congress, ESMO Virtual Congress 2020 #ESMO20, 18 Sept - 21 Sept 2020.