medwireNews: A Dutch study has found that patients with a testicular germ cell tumor (TGCT) have an increased risk for developing metachronous contralateral TGCT, and that this risk is reduced with each additional cycle of platinum-based chemotherapy.
The risk was also reduced in men of older age at diagnosis and those with a nonseminomatous (NS)GCT rather than a seminomatous (S)GCT primary tumor histology.
The study was based on data from 4755 men who were younger than 50 years of age when diagnosed with NSGCT (45.1%) or SGCT (54.9%) between 1989 and 2007 across 11 hospitals in the Netherlands. The majority (65.5%) initially presented with stage I disease.
During a median follow-up of 17.0 years, 136 patients were diagnosed with metachronous contralateral TGCT (NSGCT 28.7%, SGCT 71.3%), with a minimum 6.0-month and median 6.1-year interval between the initial and contralateral TGCT.
The risk for developing a contralateral tumor was 14.6 times higher among patients who had a TGCT than would be expected for the general population, the team reports.
The 10- and 20-year cumulative incidences of contralateral TGCT were 2.4% and 3.4%, respectively. Notably, the 20-year cumulative incidence was lower among patients who initially had NSGCT, at 2.6% versus 4.0% among those who had SGCT.
Patients whose initial TGCT was treated with a platinum-based chemotherapy had a lower 20-year cumulative incidence of contralateral TGCT than those who received a non-platinum-based treatment, at 1.7% versus 4.4%, respectively. And on multivariable analysis, the risk for developing a contralateral TGCT decreased by 26% with each additional cycle of platinum-based chemotherapy.
The study authors say in the Journal of Clinical Oncology that finding a relationship between chemotherapy and risk for contralateral TGCT is “clinically relevant, as an increasing number of patients with TGCT may receive lower doses of platinum-based chemotherapy now that adjuvant therapy with one or two cycles of chemotherapy in high-risk stage I disease is gaining popularity.”
A reduction in the risk for developing a contralateral TGCT was also associated with increasing age at diagnosis (hazard ratio [HR]=0.93) and having a primary NSGCT rather than a SGCT (HR=0.58). Indeed, the highest 20-year cumulative incidence was found in patients who were diagnosed with SGCT before the age of 25 years, at 8.7%. By contrast, the rate was 1.0% among patients who were diagnosed with NSGCT after the age of 35 years.
Michael Schaapveld (The Netherlands Cancer Institute, Amsterdam) and fellow researchers conclude: “Our findings are important for clinicians to inform patients of their risk of developing [contralateral] TGCT.”
They emphasize that “patients with TGCT should be made aware that they are at increased risk of developing [contralateral] TGCT for up to 20 years after diagnosis of the first TGCT.”
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