Docetaxel and Capecitabine in Treating Patients With Metastatic Cancer of the Stomach or Gastroesophageal Junction

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed adenocarcinoma of the stomach or gastroesophageal junction * Deemed unresectable and not a candidate for potentially curative treatment (e.g., surgical resection or combined modality therapy) * At least 4 weeks since prior abdominal exploration with resection (3 weeks without resection) * No other more conventional forms of therapy available with a reasonable chance of cure or significant palliation * Measurable disease\* * The following are not considered measurable disease: * Bone lesions * Leptomeningeal disease * Ascites * Pleural/pericardial effusion * Lymphangitis cutis/pulmonis * Abdominal masses that are not confirmed and followed by imaging * Cystic lesions NOTE: \*Patients having only lesions measuring ≥ 1 cm to \< 2 cm must use spiral CT scan for all tumor assessments. * No untreated or treated but symptomatic CNS metastases PATIENT CHARACTERISTICS: Age * 18 and over Performance status * ECOG 0-2 Life expectancy * At least 12 weeks Hematopoietic * Absolute neutrophil count at least 1,500/mm\^3 * Platelet count at least 100,000/mm\^3 Hepatic * Bilirubin no greater than upper limit of normal (ULN) * AST no greater than 2.5 times ULN if alkaline phosphatase is less than ULN OR * Alkaline phosphatase no greater than 4 times ULN if AST less than ULN Renal * Creatinine normal * Creatinine clearance at least 60 mL/min Cardiovascular * No New York Heart Association class III or IV heart disease Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * Ability to swallow capecitabine * No prior anaphylactic reaction to any taxane * No prior severe reaction to fluoropyrimidine * No prior poor tolerance to capecitabine * No known sensitivity or poor tolerance to fluorouracil * No known dihydropyrimidine dehydrogenase deficiency * No uncontrolled infection * No uncontrolled seizure disorder * No chronic debilitating disease * No peripheral neuropathy of any etiology greater than grade 1 * No diabetes mellitus * No other malignancy within the past 5 years except adequately treated basal cell or squamous cell carcinoma or adequately treated noninvasive carcinoma PRIOR CONCURRENT THERAPY: Biologic therapy * No prior immunotherapy or biologic therapy for recurrent or metastatic disease * No concurrent biologic therapy Chemotherapy * No prior chemotherapy for recurrent or metastatic disease except for the following: * Adjuvant chemotherapy after complete resection of the original tumor * Neoadjuvant chemotherapy followed by surgical resection of the original tumor * No other concurrent chemotherapy Endocrine therapy * Not specified Radiotherapy * No prior radiotherapy except for the following: * Adjuvant radiotherapy after complete resection of the original tumor * Neoadjuvant radiotherapy followed by surgical resection of the original tumor * No prior radiotherapy to 25% or more of the bone marrow * More than 4 weeks since prior radiotherapy * No concurrent radiotherapy Surgery * See Disease Characteristics * No prior organ allograft Other * No concurrent brivudine or sorivudine