The role of chemotherapy in the management of patients with SCCHN has not been adequately defined. For patients with recurrent or metastatic disease, several single agents can induce significant tumor regression in 20% to 40% of cases and provide palliation for the individual with a symptomatic or life-threatening lesion. However, complete or long-term control of tumor with chemotherapy alone remains poor. In addition, current regimens of combination chemotherapy have not proved superior to single agents in this setting. Thus, the routine use of combination chemotherapy for patients with metastatic or recurrent SCCHN cannot be justified outside an investigational study. New single agents of promise must be sought and more active combinations of chemotherapy devised for the treatment of patients with metastatic or recurrent SCCHN. Strategies for drug development include the investigation of cisplatin analogues, such as iproplatin and carboplatin, the exploitation of potentially synergistic drug schedules, and the administration of chemotherapy by continuous infusion. That the use of continuous-infusion drug delivery can enhance antitumor activity and limit toxicity for patients with recurrent or metastatic SCCHN was convincingly demonstrated by Kish and co-workers132 in a randomized trial of cisplatin with either bolus or continous-infusion 5-fluourouracil. The antitumor activity of combination chemotherapy may also be increased by the use of mid-cycle nonmyelosuppressive agents, such as methotrexate with leucovorin rescue, or the administration of alternating cycles of non-cross-resistant regimens of combination chemotherapy. The optimal use of chemotherapy in the multidisciplinary treatment of patients with previously untreated SCCHN must also be clarified. Uncontrolled studies of induction chemotherapy report increasingly positive results. Several regimens of induction combination chemotherapy are now associated with significant tumor regression in 70% to 90% of patients, and complete clinical regression of tumor in 20% to 50%. Of patients with a complete clinical response to induction chemotherapy, a complete pathologic response has been documented in 30% to 70% of patients who undergo surgical resection after chemotherapy. It is now evident that patients achieving a complete response to induction chemotherapy have a high probability of local-regional control of tumor and cure. Conversely, patients not responding to induction chemotherapy fare poorly regardless of subsequent local treatment, and it may be appropriate to defer excessively morbid surgical procedures in this patient populus.(ABSTRACT TRUNCATED AT 400 WORDS)