Carcinoma in situ (CIS) is part of the histopathologic spectrum of lar
yngeal disorders where invasive squamous cell carcinoma is the endpoin
t of cellular disarray. Few reports consider prognostic indicators tha
t predict which lesions become invasive. Forty-one patients with CLS o
f the glottic larynx were analyzed for risk factors that would predict
invasive cancer. Anterior commissure involvement by CIS resulted in 9
2% conversion to invasive squamous cell cancer compared to 17% of lesi
ons limited to the mobile fold. Epidermal growth factor receptors were
also analyzed and were found not to be helpful in predicting invasion
. Lesions of the mobile fold should be removed endoscopically and the
patient should be observed closely for recurrence. Anterior commissure
involvement that is inaccessible to complete laser ablation should be
radiated, and the patient should be observed carefully.