Analysis of 798 testicular cancer survivors reveals that four cycles of etoposide-cisplatin (EPx4) produce 55% higher odds of kidney impairment compared to three cycles of bleomycin-etoposide-cisplatin (BEPx3), with reduced glomerular filtration rates observed in 41% of survivors. The cumulative cisplatin dose showed direct correlation with declining kidney function, while EPx4 recipients also faced 48% higher ototoxicity risk and 77% increased neuropathy odds. These findings address a critical knowledge gap in oncology's risk-benefit calculus. While both regimens achieve excellent cancer cure rates, the EPx4 protocol's additional cisplatin exposure creates measurably worse long-term morbidity profiles. For young men facing testicular cancer—often in their twenties and thirties—these toxicity differences compound over decades of survivorship. The kidney damage particularly matters because reduced filtration rates below 90 mL/min/1.73m² correlated with 2-to-20-fold increased hypertension risk. This real-world evidence from survivors averaging 11 years post-treatment suggests oncologists should weigh the marginal efficacy gains of four-cycle regimens against substantially higher lifetime toxicity burdens, especially given testicular cancer's already favorable prognosis with less intensive protocols.