(UroToday.com) It is known that men with testicular germ cell tumors are at an increased risk of developing a metachronous contralateral testicular germ cell tumor. Data on this risk from large population-based studies are scarce. It is currently unclear whether treatment with chemotherapy leads to a lower risk of a contralateral testicular germ cell tumor developing.

In this presented study, the authors attempted to evaluate the risk of a contralateral testicular germ cell tumor in a large population-based cohort. They also analyze whether the contralateral testicular germ cell tumor is associated with previous treatment with chemotherapy.

All men with a primary diagnosis of testicular germ cell tumors between 1989 and 2007 were included. All men were younger than 50 at primary diagnosis, and a total of 11 Dutch hospitals were included, using the Netherlands cancer registry. The primary endpoint was metachronous contralateral testicular germ cell tumor development, diagnosed at least two months after the primary testicular germ cell tumor was discovered.

This was a case-cohort analysis with a randomly selected hospital stratified subcohort. The authors used an estimation of cumulative incidence with death as a competing risk.

A total of 4755 men were included in this analysis, as can be shown in Table 1. Contralateral testicular germ cell tumor was diagnosed in 136 patients with a median interval to this diagnosis being 6.1 years (range 0.8-19.7 years). No contralateral testicular germ cell tumor was diagnosed after 20 years of follow-up. The total 20-year cumulative incidence of contralateral testicular germ cell tumor was 3.4%, as can be seen in Table 2. The incidence of a contralateral testicular germ cell tumor was 14.6 times higher when compared to the incidence of a testicular germ cell tumor in the general population.

Table 1 — Patient Characteristics: 

Table 2 — Cumulative Incidence: 

The incidence was lower in patients who were previously treated with chemotherapy (2.6% vs. 3.6%). In a multivariable Cox regression analysis, the risk of contralateral testicular germ cell tumor decreased with increased age, was lower for non-seminoma germ cell tumor compared to seminoma, and decreased with every additional cycle of chemotherapy that the patient had originally received (Table 3). The communitive incidence of metachronous contralateral testicular germ cell tumors can be seen in Figure 1.

Table 3 — Association with CTGCT: 

Figure 1:

The authors concluded that patients with testicular germ cell tumors have an almost 15 times higher incidence of developing a contralateral testicle germ cell tumor compared to the general population. The risk of contralateral testicular germ cell tumors is higher in patients with a non-seminoma germ cell tumor and decreases with every additional cycle of chemotherapy that they received. It is recommended that these patients perform a self-examination for a long-term period of at least 20 years.

Presented by: Joost Blok, MD, University Medical Center Utrecht, Utrecht, NLD

Written by: Hanan Goldberg, MD, MSc., Urology Department, SUNY Upstate Medical University, Syracuse, NY, USA, Twitter: @GoldbergHanan, at the 2020 American Urological Association (AUA) Annual Meeting, Virtual Experience #AUA20, June 27- 28, 2020

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