Bortezomib in Treating Patients With Recurrent or Refractory Extensive-Stage Small Cell Lung Cancer Previously Treated With Platinum-Based Chemotherapy

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed extensive stage small cell lung cancer * Diagnosis by sputum cytology allowed provided it is confirmed by an independent pathologic review * Clinical evidence of recurrent or refractory disease does not require a confirmatory biopsy * Measurable disease by plain radiographs, CT scan, or MRI * Prior radiotherapy to measurable disease allowed provided there is evidence of disease progression by CT scan OR there is measurable disease outside of the radiotherapy field * Must have received a prior platinum-based chemotherapy regimen and meet criteria for 1 of the following: * Platinum-sensitive disease, defined as an initial response with subsequent progression more than 90 days after last platinum treatment (temporarily closed to accrual as of 8/1/04) * Platinum-refractory disease, defined as no response to or progression during platinum treatment or subsequent progression no more than 90 days after last platinum treatment (temporarily closed to accrual as of 6/1/04) * Brain and/or leptomeningeal metastases are allowed provided all of the following are true: * Asymptomatic on neurological exam * No concurrent corticosteroids for symptom control * No concurrent enzyme-inducing anticonvulsants (e.g., phenytoin or phenobarbital) PATIENT CHARACTERISTICS: Age * 18 and over Performance status * Zubrod 0-1 Life expectancy * Not specified Hematopoietic * Absolute neutrophil count at least 1,500/mm\^3 * Platelet count at least 100,000/mm\^3 Hepatic * Not specified Renal * Creatinine no greater than upper limit of normal OR * Creatinine clearance at least 60 mL/min Other * Not pregnant or nursing * Fertile patients must use effective contraception * No symptomatic sensory neuropathy greater than grade 1 * No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer, carcinoma in situ of the cervix, or any other adequately treated stage I or II cancer currently in complete remission PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * See Disease Characteristics * At least 3 weeks since prior chemotherapy Endocrine therapy * See Disease Characteristics Radiotherapy * See Disease Characteristics * At least 3 weeks since prior radiotherapy * No concurrent radiotherapy to measurable lesions Surgery * At least 14 days since prior thoracic or other major surgery and recovered * Must have disease outside of the prior surgical resection area OR new lesion must be present