PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Hematopoietic: Absolute neutrophil count greater than 500/mm3 Platelet count greater than 50,000/mm3 Hepatic: Bilirubin less than 2.0 times upper limit of normal (ULN) AST/ALT no greater than 3.0 times ULN Renal: Creatinine no greater than 1.5 times ULN Other: No acute illness within 1 week of start of study No other illness that would significantly interfere with study outcome No major medical illness that precludes prolonged marimastat administration No second malignancy within 5 years except: Adequately treated basal cell carcinoma of the skin In situ carcinoma of the cervix Not pregnant or nursing Medically approved method of contraception required of fertile women Willing and able to tolerate and comply with study requirements