Time patterns of recurrence and second primary tumors in a large cohort of patients treated for oral cavity cancer

Introduction: Routine follow-up after curative treatment of patients with oral squamous cell carcinoma (OSCC) is common practice considering the high risk of second primaries and recurrences (ie second events). Current guidelines advocate a follow-up period of at least 5 years. The recommendations are not evidence-based and benefits are unclear. This is even more so for follow-up after a second event. To facilitate the development of an evidence- and personalized follow-up program for OSCC, we investigated the course of time until the second and subsequent events and studied the risk factors related to these events. Materials and methods: We retrospectively studied 594 OSCC patients treated with curative intent at the Head and Neck Cancer Unit of the Radboud University Medical Centre from 2000 to 2012. Risk of recurrence was calculated addressing death from intercurrent diseases as competing event. Results: The 1-, 5- and 10-year cumulative risks of a second event were 17% (95% CI:14%;20%), 30% (95% CI:26%;33%), and 37% (95% CI:32%;41%). Almost all locoregional recurrences occurred in the first 2 years after treatment. The incidence of second primary tumors was relatively stable over the years. The time pattern of presentation of third events was similar. Discussion: Our findings support a follow-up time of 2 years after curative treatment for OSCC. Based on the risk of recurrence there is no indication for a different follow-up protocol after first and second events. After 2 years, follow-up should be tailored to the individual needs of patients for supportive care, and monitoring of late side-effects of treatment.