DISEASE CHARACTERISTICS: Histologically confirmed squamous cell carcinoma of the head and neck considered incurable by surgery or radiotherapy Newly diagnosed extensive locoregional disease or distant metastases Locoregionally recurrent or persistent disease, or distant metastases occurring after initial surgery or radiotherapy No nasopharyngeal carcinoma No history of brain metastases Measurable or evaluable disease Documented progressive disease or biopsy-proven residual carcinoma required if sole measurable site previously irradiated