Kaplan-Meier estimates of disease-free survival for 185 patients presenting with HNSCC, based on cell line formation. Failure is defined as the occurrence of a new primary, recurrence, metastasis or death, and includes any subsequent tumors (HNSCC or otherwise) or death. For patients with multiple HNSCC, the date of the first tumor is used to estimate survival time. The median disease-free survival time for an individual presenting with an HNSCC that yielded a cell line is 10 months, and the mean time for an HNSCC that did not yield a cell line is 37 months (log-rank test for equality of survivor functions; p<0.05).