medwireNews: Men who receive platinum-based chemotherapy (PBCT) or radiotherapy (RT) for testicular cancer have significantly higher long-term non-testicular cancer mortality rates than the general population, study findings indicate.
The results of the population-based cohort study, presented at the 2021 ASCO Annual Meeting, also showed that the youngest testicular cancer patients had the greatest excess mortality risk and that non-testicular second cancers were the biggest cause of excess deaths.
For the study, Ragnhild Hellesnes (University Hospital of North Norway, Tromsø) and colleagues retrieved complete treatment details from the medical records of 5707 men diagnosed with testicular cancer in Norway between 1980 and 2009 and linked their findings to data from the Norwegian Cause of Death Registry.
The men had a median age of 33.1 years at diagnosis and were treated with PBCT (44%), RT (27%), surgery (25%), or a combination of PBCT and RT (4%).
Hellesnes told delegates that, during a median follow-up of 18.7 years, 11.7% of study participants died of non-testicular cancer causes.
She reported that the risk for non-testicular cancer mortality was a significant 23% higher than that in the general population (standardized mortality ratio [SMR]=1.23) and that the risk varied by treatment type.
For people who received PBCT, the SMR was 1.23, while for those who had RT it was 1.28, increasing to 2.04 for those who received a combination of both PBCT and RT.
Conversely, there was no excess non-testicular cancer mortality among the individuals whose testicular cancer was only treated with surgery.
The researchers observed that the excess non-testicular cancer mortality was time-dependent, and only increased significantly from 10 years of follow-up and beyond, reaching a maximum SMR of 1.64 after 30–39 years.
It was also age-dependent, Hellesnes pointed out. Specifically, the SMR was a significant 2.27 for people who were younger than 20 years at diagnosis, falling to 1.42 for those aged 40–50 years, and was then not significantly increased among people diagnosed after 50 years of age.
Non-testicular second cancers were the most important cause of excess death, with SMRs of 1.43 after PBCT, 1.59 after RT, and 3.24 after both. The risks also varied by cancer type and were highest for oropharyngeal cancer after PBCT and bladder cancer after RT.
“It is important that health professionals and testicular cancer survivors are aware of this [excess second cancer] risk to ensure diagnosis at the earliest possible stage,” Hellesnes remarked.
She added: “Lifestyle improvements seem important in this group of cancer survivors.”
For non-cancer mortality, the investigators found that there was a significant 23% excess risk after PBCT, a 17% excess risk after RT, and a 55% excess risk after both treatments.
In the PBCT group, a notable finding was a 65% higher risk for death by suicide relative to the general population, which Hellesnes said “calls for health professionals’ awareness toward suicide risk factors in testicular cancer survivors in order to hopefully prevent future deaths by suicide.”
Conversely, long-term cardiovascular mortality was not significantly higher than that seen in the general population either overall or according to treatment modality.
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