RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining more than one chemotherapy drug may kill more tumor cells.

PURPOSE: Phase I trial to study the effectiveness of capecitabine combined with cisplatin in treating patients who have locally advanced or metastatic solid tumors .

OBJECTIVES:

• Determine the dose-limiting toxicity, maximum tolerated dose, and the recommended phase II dose of capecitabine and cisplatin in patients with locally advanced or metastatic cancer of the upper gastrointestinal tract (GI), head and neck, lung, breast, or carcinoma of unknown primary.
• Determine the toxic effects of this regimen in these patients.
• Evaluate possible antitumor effectiveness of this regimen in these patients.
• Determine the toxic effects of cisplatin and capecitabine at the recommended phase II dose in patients with cancer of the upper GI tract.
• Determine the overall survival, time to progression, and duration of response in patients treated with this regimen.

OUTLINE: This is a dose-escalation study of capecitabine.

Patients receive oral capecitabine twice daily for 5, 10, or 14 days. Patients also receive cisplatin IV on day 1 of each course. Treatment repeats every 21 days in the absence of disease progression or unacceptable toxicity.

Cohorts of 3-6 patients receive escalating doses of capecitabine until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose at which 2 of 3 or 2 of 6 patients experience dose-limiting toxicity (DLT). The recommended phase II dose is defined as the dose preceding the MTD, provided no more than 3 of 12 patients experience DLT at that dose. Twenty additional patients with cancer of the upper gastrointestinal tract receive treatment with cisplatin and capecitabine at the recommended phase II dose for at least 6 months in the absence of disease progression or unacceptable toxicity.

Patients are followed every 3 months for 6 months and then every 6 months thereafter.

PROJECTED ACCRUAL: A total of 20-50 patients will be accrued for this study within 1-3 years.

• Drug: capecitabine
• Drug: cisplatin

DISEASE CHARACTERISTICS:

• Histologically confirmed metastatic or locally advanced inoperable carcinoma of the upper gastrointestinal tract, head and neck, lung, breast, or carcinoma of unknown primary
• Previously treated and/or resected primary tumors allowed

• Hormone receptor status:

  • Not specified

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Sex:

• Not specified

Menopausal status:

• Not specified

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 less than 2 mg/dL*
• AST less than 3 times upper limit of normal (ULN)*
• Alkaline phosphatase no greater than 3 times ULN* NOTE: * Unless related to tumor (e.g., cholangiocarcinoma or hepatic metastases)

Renal:

• Creatinine no greater than 1.5 mg/dL OR
• Creatinine clearance greater than 60 mL/min
• BUN no greater than 30 mg/dL* NOTE: * Unless related to tumor (e.g., cholangiocarcinoma or hepatic metastases)

Other:

• No other medical condition that could interfere with oral medication absorption
• No prior or concurrent malignancy except surgically cured carcinoma of the cervix or basal cell or squamous cell carcinoma skin cancer
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• HIV negative

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• At least 6 months since prior fluorouracil or cisplatin
• At least 3 weeks since other prior chemotherapy

Endocrine therapy:

• Not specified

Radiotherapy:

• At least 3 weeks since prior radiotherapy

Surgery:

• See Disease Characteristics