Bortezomib, Paclitaxel, and Carboplatin in Treating Patients With Unresectable, Metastatic Cancer of the Esophagus or Gastroesophageal Junction

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed adenocarcinoma of 1 of the following sites: * Esophagus * Gastroesophageal junction * Gastric cardia * No greater than 2 cm from the gastroesophageal junction into the stomach * Unresectable, metastatic disease * Not a candidate for potentially curative therapy AND no other more reasonable potentially curative conventional therapy exists * At least 1 measurable lesion ≥ 2.0 cm by conventional techniques OR ≥ 1.0 cm by spiral CT scan * No known CNS metastases PATIENT CHARACTERISTICS: Age * 18 and over Performance status * ECOG 0-2 Life expectancy * At least 12 weeks Hematopoietic * Absolute neutrophil count ≥ 1,500/mm\^3 * Platelet count ≥ 100,000/mm\^3 Hepatic * Bilirubin normal * AST ≤ 3 times upper limit of normal (ULN) * Alkaline phosphatase ≤ 2 times ULN Renal * Creatinine ≤ 1.5 times ULN Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception during and for up to 6 months after completion of study treatment * No peripheral neuropathy ≥ grade 2 * No uncontrolled infection * No chronic debilitating disease * No prior allergic reaction to carboplatin or paclitaxel * No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer PRIOR CONCURRENT THERAPY: Biologic therapy * No prior immunotherapy for recurrent or metastatic disease * No prior biologic therapy for recurrent or me…