Cisplatin With or Without Raltitrexed in Treating Patients With Malignant Mesothelioma of the Pleura

DISEASE CHARACTERISTICS: Histologically confirmed malignant pleural mesothelioma No CNS metastases PATIENT CHARACTERISTICS: Age: Over 18 Performance status: ZUBROD, ECOG, WHO 0-2 Life expectancy: Not specified Hematopoietic: Hemoglobin at least 10.0 g/dL WBC at least 4,000/mm^3 Absolute neutrophil count at least 2,000/mm^3 Platelet count at least 100,000/mm^3 Hepatic: Bilirubin less than 1.46 mg/dL Albumin at least 3.0 g/dL ALAT/ASAT less than 2.5 times upper limit of normal (ULN) (less than 5 times ULN if liver involvement) Renal: Creatinine less than 1.69 mg/dL Creatinine clearance at least 65 mL/min Cardiovascular: Not specified Pulmonary: Not specified Other: No other prior or concurrent malignancies within past 5 years except adequately treated carcinoma in situ of the cervix or basal or squamous cell carcinoma of the skin No prior malignant melanoma, hypernephroma or breast carcinoma Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during and for 6 months after study No uncontrolled infections No psychological, familial, sociological, or geographical condition that precludes study compliance PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent immunotherapy before first disease progression Chemotherapy: No prior systemic or intracavitary cytotoxic chemotherapy No other prior or concurrent chemotherapy before first disease progression No prior or concurrent pleurodesis with cytotoxic drugs (e.g., bleomycin) Endocrine therapy: No concurrent hormonal therapy except corticosteroids before first disease progression Radiotherapy: At least 4 weeks since prior radiotherapy to target lesion and progression observed Concurrent palliative radiotherapy to painful lesions allowed only if target lesion outside of irradiated field Surgery: Prior surgery allowed if followed by disease progression Other: At least 1 month since prior investigational drugs