Dose-Dependent Concentration and Penetration Depth of Cisplatin in Human Lung Tissue During Hyperthermic Exposure

Background: Hyperthermic intrathoracic chemotherapy (HITOC) is an additive treatment option after surgical cytoreduction of pleural malignancies. Despite growing clinical experience and studies evaluating its feasibility, postoperative morbidity and mortality, as well as the effect on survival, there is still only little known about the local effects of HITOC on the lung parenchyma and tumour cells. The objective of this in vitro study was to evaluate the dose-dependent concentration and penetration depth of cisplatin in human lung tissue. Methods: In total, 40 patients were enrolled for elective lung resection, and wedge samples were taken to the laboratory. The visceral pleura was removed, and the decorticated lung tissue was incubated in cisplatin solutions of different concentrations (0.05, 0.075, and 0.1 mg/mL) at 42 °C over 60 min. Afterwards, platinum amounts in the lung tissue samples were measured using atomic absorption spectroscopy. Results: A strong decline of the cisplatin concentration was found until a depth of 3.5 mm, followed by a mild decline until a depth of 7.5 mm. In a depth of 0.5 mm, there was only a significant difference between 0.05 and 0.1 mg/mL (p = 0.03, Cohen's d = 0.43). In a depth of 1.5 mm, there was an overall significant difference in cisplatin concentration dependent on dose (p = 0.027). In deeper tissue layers, no significant difference in cisplatin concentrations in the tissue was found. Conclusions: A dose-dependent increase of the cisplatin concentration was found for superficial tissue layers. This emphasises the relevance of sufficiently high intrathoracic concentrations of the chemotherapeutic agent. This study confirms that cisplatin penetrates lung tissue in therapeutically effective concentrations.