Barone-Adesi F, Ferrante D, Bertolotti M, Todesco A, Mirabelli D, Terracini B, Magnani C.

Unit of Cancer Epidemiology, CeRMS and Center for Oncologic Prevention Piemonte, University of Turin, Turin, Italy.

Abstract

Models based on the multistage theory of carcinogenesis predict that the rate of mesothelioma increases monotonically as a function of time since first exposure (TSFE) to asbestos. Predictions of long-term mortality (TSFE >/= 40 years) are, however, still untested, because of the limited follow-up of most epidemiological studies. Some authors have suggested that the increase in mesothelioma rate with TSFE might be attenuated by clearance of asbestos from the lungs. We estimated mortality time trends from pleural and peritoneal cancer in a cohort of 3,443 asbestos-cement workers, followed for more than 50 years. The functional relation between mesothelioma rate and TSFE was evaluated with various regression models. The role of asbestos clearance was explored using the traditional mesothelioma multistage model, generalized to include a term representing elimination over time. We observed 139 deaths from pleural and 56 from peritoneal cancer during the period 1950-2003. The rate of pleural cancer increased during the first 40 years of TSFE and reached a plateau thereafter. In contrast, the rate of peritoneal cancer increased monotonically with TSFE. The model allowing for asbestos elimination fitted the data better than the traditional model for pleural (p = 0.02) but not for peritoneal cancer (p = 0.22). The risk for pleural cancer, rather than showing an indefinite increase, might reach a plateau when a sufficiently long time has elapsed since exposure. The different trends for pleural and peritoneal cancer might be related to clearance of the asbestos from the workers’ lungs.

Keywords: asbestos, mesothelioma, multi-stage model, latency, clearance

Guadagni S, Clementi M, Valenti M, Fiorentini G, Cantore M, Kanavos E, Amicucci G.

Department of Surgical Sciences, University of L’Aquila, Italy. stefanoguadagni@interfree.it

Abstract

Malignant pleural mesothelioma (MPM) is an aggressive treatment-resistant tumor with a median survival from diagnosis of 12 months. Although multimodality protocols that combine aggressive surgery and adjuvant chemotherapy or radiotherapy have shown improved survival in selected cases, the majority of patients with MPM are not suitable for radical surgery due to advanced stage and comorbid medical illness. For these patients combination chemotherapy with Pemetrex and Cisplatin should be considered for first line palliative chemotherapy. The therapeutic options available to patients with MPM resistant or refractory to systemic chemotherapy are very limited. Thoracic “stop-flow” perfusion (TSP) is a semi-invasive loco-regional drug delivery system that, limiting the circulation to the thorax during the anticancer agent’s infusion, claims the advantage of reaching high drug concentration at the tumor site while maintaining a low systemic toxicity. The aim of this phase I-II study was to evaluate the toxicity profile and efficacy of two different platinum-based combined regimens–cisplatin plus mitomycin-C (MMC) and cisplatin plus melphalan (L-PAM)–administered using TSP technique in patients with advanced or recurrent MPM who had refractory disease after systemic first line chemotherapy. Patients with histologically proven unresectable stage II-III MPM entered this trial. Between January 1995 and December 2001, 27 patients were enrolled in the study and submitted to TSP using the two different chemotherapy cisplatin based regimens: 12 patients received cisplatin 100 mg/m2 plus MMC 20 mg/m2 (MMC arm) and 15 cisplatin 100 mg/m2 plus L-PAM 50 mg/m2 (L-PAM arm). Objective responses were assessed by CT-scan 30 and 60 days after the end of treatment in all 27 enrolled patients. Two patients (7.4%) achieved a complete response, 2 (7.4%) a partial response and 4 (14.8%) a minor response. The remaining 19 patients (70.3%) showed a stable disease. No patients developed progression of the disease following the first TSP. The overall median time to progression was 8.9 months (range 1-41). The median survival time for all patients from the beginning of regional chemotherapy was 16.6 months, with a 1-year survival rate of 62.9%, a 2-year survival rate of 18.5%, and a 3-year survival rate of 7.4%. Our data show that TSP is a relatively effective second-line treatment in patients with progressive disease after systemic chemotherapy, with a low rate of major complications and treatment-related toxicity.