Quantitative evaluation of the intratumoral distribution of platinum in oxaliplatin-treated rectal cancer: In situ visualization of platinum via synchrotron radiation X-ray fluorescence spectrometry.
Int J Cancer. 2019 Jul 25;:
Authors: Koba R, Fujita H, Nishibori M, Saeki K, Nagayoshi K, Sadakari Y, Nagai S, Sekizawa O, Nitta K, Manabe T, Ueki T, Ishida T, Oda Y, Nakamura M
Oxaliplatin, a platinum-based drug, is a key chemotherapeutic agent for colorectal cancer (CRC), but drug resistance and toxic effects have been major limitations of its use. Synchrotron radiation X-ray fluorescence spectrometry (SR-XRF) is a rapid, non-destructive technique for monitoring the distribution of metals and trace elements in cells or tissue samples. We applied SR-XRF to visualize the distribution of platinum and other elements in 30 rectal cancer specimens resected from patients who received oxaliplatin-based preoperative chemotherapy and quantified platinum concentration in the tumor epithelium and stroma, respectively, using calibration curves. The platinum concentration in rectal cancer tissue ranged 2.85-11.44 ppm, and the detection limit of platinum was 1.848 ppm. In the tumor epithelium, the platinum concentration was significantly higher in areas of degeneration caused by chemotherapy than in non-degenerated area (p < 0.001). Conversely, in the tumor stroma, the platinum concentration was significantly higher in patients with limited therapeutic responses than in those with strong therapeutic responses (p < 0.001). Furthermore, multivariate analysis illustrated that higher platinum concentration in the tumor stroma was an independent predictive factor of limited histologic response (Odds Ratio; 19.99, 95% confidence interval; 2.04-196.37, p = 0.013). This is the first study to visualize and quantify the distribution of platinum in human cancer tissues using SR-XRF. These results suggest that SR-XRF analysis may contribute to predicting the therapeutic effect of oxaliplatin-based chemotherapy by quantifying the distribution of platinum. This article is protected by copyright. All rights reserved.
PMID: 31344279 [PubMed – as supplied by publisher]