Purpose: To assess the progression of precancerous laryngeal lesions to squamous cell carcinoma (SCC), defined by specific histopathological criteria, in patients with longterm follow-up.
Methods: Patients with laryngeal dysplasia, followed/ treated between 1985 and 2008, were retrospectively evaluated and classified according to the World Health Organization classification system (WHO). The investigated outcome parameters were progression of dysplasia to SCC, time interval to malignant transformation and continuation of smoking as potential risk factors.
Results: Fifty-nine patients were studied. Progression of dysplasia to SCC between the first and the final histological examination was statistically significant (p<0.0001). Malignant transformation appeared in 29 patients (49.2%). Serious dysplasia was more likely to progress to SCC (64.8%) compared to mild (41.7%) or moderate (44.4%) (p<0.0001). However, the time interval needed in these 29 cases to progress to cancer was not statistically related to the initial histological diagnosis. Continuation of smoking did not affect the progression of disease. However, the mean time from dysplasia to laryngeal cancer was much longer in patients who quitted smoking (33.5 months) vs those who continued smoking (19.5 months), with a marginal statistical difference (p=0.057).
Conclusion: All patients with laryngeal dysplasia should be followed up at regular intervals. The progression of dysplasia to SCC did not seem to be directly related to the continuation of smoking or not. However, large long-term follow- up studies taking into account the degree of exposure (e.g. time of exposure, number of cigarettes) are needed in order to clarify risk factors and proper management. Consensus guidelines in diagnosis, follow-up, and treatment would improve substantially the current clinical practice.