Progressive increasing in the risk of second and subsequent malignant tumors in patients with a head and neck cancer: A validation study with SEER data.

Abstract

5595 Background: Patients with a head and neck squamous cell carcinoma (HNSCC) index tumor have a increased risk (2-4% per year) for appearance of a second malignant neoplasms (SMN) and higher risk for successive malignant tumors during the follow-up. The objective of our study was to validate this concept with data of patients included in the Surveillance Epidemiology and End Results (SEER) program (1973-2008). Methods: We performed a population-based cohort study of 149.328 patients with a primary oral cavity, oropharynx, hypopharynx and larynx squamous cell carcinoma index tumor, included in the SEER program, to analize the actuarial survival-free of second and successive tumors. A total of 11.948 (8%) patients had one or more malignant tumors before the diagnosis of HNSCC. Results: During the follow-up period, a total of 31.507 new SMN appeared. There was a progressive and significant increase in the risk of SMN. The annual hazard ratio for 2nd to 7th successive SMN was 2.3%, 2.7%, 3.9%, 5.4%, 8.9% and 19.1% annual risk respectively. Additionally 11 patients had 8th SMN. We observed a progressive increase in the risk of appearence of new malignant tumors located in and outside the aerodigestive tract. The increase in the risk of SMN was higher for tumors located in the aerodigestive tract than tumors located outside aerodigestive tract. It was a tendency towards the increase in the proportion of HNSCC with the appearance of new tumors, with a decrease in the proportion of the malignant tumors located in the lung and in locations outside the aerodigestive tract. There were significant differences inthe risk of SMN between second and third, third and fourth, fourth and fifth, and sist and seventh tumors (p<0.0001). Conclusions: In patients with HNSCC there is a progressive increase in the risk of appearance of successive tumors. Previous tobacco and alcohol consumption, persistence in the exposure to carcinogens and individual susceptibility (genetic) could play a role in the increased risk of SMN. We have validated this concept with data from the SEER program.