The purpose of phase II trials is to determine if a drug or drug combination tested in patients with the same tumor type has enough activity to warrant further testing in a comparative trial. Phase III trials are randomized comparisons of two or more treatment options, often comparing a standard treatment to a new or more complex therapy.Response rate, disease-free survival, or response duration and survival are primary endpoints.Stable disease No appreciable change in dimensions of all evaluable lesions.

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Criteria for response Complete response Complete disappearance of all evidence of tumor for at least 4 weeks.

Partial response Disease regression by at least 50% of the sum of the product of the perpendicular diameters of all measurable tumor for at least 4 weeks.

The determination of sample size, patient entry criteria, and the follow-up evaluation and monitoring of patients are critical for a valid interpretation of a phase III trial.[161] Standard definitions exist for the various endpoints in clinical trials that allow objective reporting of results.

Definitions of response are complete, partial, minor, stable, and progressive disease ( Box 6–1 ).

The goals of phase I trials are to determine the toxic effects associated with a new drug and to establish the highest dose of the drug that can be safely administered.

Patients with different tumor types refractory to conventional chemotherapy are enrolled.Many have previously undergone surgery and radiotherapy.Chemotherapy also is indicated for those with advanced carcinomas of the larynx as part of primary curative treatment when voice preservation is desired.Disease-free survival is calculated from study entry until disease progression or from achievement of complete response until disease progression.Duration of response is calculated from response date until date of disease progression.Melanomas and sarcomas also are seen in the head and neck, although they are much rarer.