Second malignant neoplasia in patients with T1 glottic cancer treated with radiation.

OBJECTIVE/HYPOTHESIS: To evaluate incidence, site of occurrence and outcome of second malignant neoplasia (SMN) in patients with T1 glottic cancer treated with radiation. STUDY
DESIGN: Retrospective.
METHODS: Between February 1964 and May 1993, 158 patients with T1 squamous carcinoma of the larynx were treated with definitive radiation. Incidence, site (aerodigestive tract or not) and outcome of SMN were analyzed. Median follow-up was 63 months (range, 12-245 mo).
RESULTS: Thirty-four patients developed SMN, for an overall incidence of 22%. Twenty-four (67%) SMNs occurred in an aero-upper-digestive-tract site compared with nine (25%) occurring in a non-aero-upper-digestive tract site. The incidence of SMN observed was higher than would be expected for the general population at risk. The observed-to-expected ratios (OER) for all SMN, aero-upper-digestive SMN and non-aero-upper-digestive SMNs were 1.73, 5.53, and 0.62, respectively. Overall 5- and 10-year survivals were 76% and 57%, respectively, for those who did not develop SMN, as compared with 68% and 26%, for those who developed SMN (P = .003). Overall, 13 patients (8.2%) have died from laryngeal cancer, while 23 (15%) died from SMN (P = .001).
CONCLUSION: This study confirms a higher incidence of SMN in T1 glottic cancer patients, compared with the general population. The majority of cases occur in aero-upper-digestive sites. These patients are more likely to die from their SMN than from glottic cancer. Patients with T1 squamous cell carcinoma of the glottic larynx represent a group of head and neck cancer patients who should be targeted in studies evaluating the potential benefits of chemoprevention, and aggressively counseled for social and/or behavioral modifications.