FACTORS AFFECTING PLATINUM CONCENTRATIONS IN HUMAN SURGICAL TUMOR SPECIMENS AFTER CISPLATIN

We assessed factors which affect cisplatin concentrations in human sur gical tumour specimens. Cisplatin 10 mg m(-2) was given i.v. to 45 con senting patients undergoing surgical resection of neoplasms, and plati num was assayed in resected tumour and in deproteinated plasma by flam eless atomic absorption spectrophotometry. By multiple stepwise regres sion analysis of normalised data, patient characteristics that emerged as being most closely associated (P<0.05) with tumour platinum concen trations (after correcting for associations with other variables) were tumour 'source' [primary brain lymphomas, medulloblastomas and mening iomas ('type LMM')>'others'>lung cancer>head/neck cancer>gliomas) or t umour 'type' (LMM>brain metastases>extracerebral tumours>gliomas), ser um calcium and chloride (positive correlations) and bilirubin (negativ e). Tumour location (intracranial vs extracranial) did not correlate w ith platinum concentrations. If values for a single outlier were omitt ed, high-grade gliomas had significantly higher platinum concentration s (P<0.003) than low-grade gliomas. For intracranial tumours, the comp uterised tomographic scan feature that correlated most closely with pl atinum concentrations in multivariate analysis was the darkness of per itumoral oedema. Tumour source or type is a much more important correl ate of human tumour cisplatin concentrations than is intracranial vs e xtracranial location. Serum calcium, chloride and bilirubin levels may affect tumour cisplatin uptake or retention. CT scan characteristics may help predict cisplatin concentrations in intracranial tumours.