Long-term serum platinum changes and their association with cisplatin-related late effects in testicular cancer survivors

<b>Background:</b> The long-term toxicities after cisplatin-based chemotherapy (CBCT) reveal a remarkable inter-individual variation among testicular cancer survivors (TCSs). Therefore, we assessed long-term platinum (Pt) changes and their associations with CBCT-related late effects in TCSs. <b>Material and methods:</b> In 77 TCSs treated with CBCT from 1984 to 1990, blood samples for analyses of Pt and a questionnaire including self-reported neuro- and ototoxicity (NTX) symptoms were collected during two follow-up surveys at median 12 (Survey I; SI) and 20 (Survey II; SII) years after treatment. Information about second cancers after SII was retrieved from the Norwegian Cancer Registry. <b>Results:</b> A larger Pt decline from SI to SII was associated with a decreased risk of a second cancer diagnosis (HR 0.78, 95% CI 0.62–0.99 per 10 ng/L/year), and worsening of paresthesias in hands (OR 1.98, 95% CI 1.09–3.59 per 10 ng/L/year) and tinnitus (OR 1.51, 95% CI 1.01–2.27 per 10 ng/L/year). <b>Conclusion:</b> In summary, we found a significant association between a larger Pt decline and a reduced risk of second cancers and deterioration of paresthesias in hands and tinnitus.