The learning curve in transoral laser microsurgery for malignant tumors of the larynx and hypopharynx: parameters for a levelled surgical approach.

The goal of the study was to identify parameters helpful to define a learning curve for laser microsurgery (TLM). 587 patients with malignant tumors of larynx and hypopharynx treated with TLM were divided into groups depending on the number of interventions their surgeons had performed. Outcome measures were obtained for the number of revision surgeries and complications, rates for tumor-free margins, tumor relapse and disease-specific survival rates for early and advanced tumors, serving to evaluate their potential influence on the learning curve. Surgery of early tumors was not influenced by the grade of experience. For locally advanced tumors the learning curve was statistically related to the number of surgeries needed per patient (p = 0.018). The number of overall complications (p = 0.000) and the disease-specific survival rate (p = 0.019) was significantly lower in the "expert" group. The percentage of postoperative bleedings was similar between all groups. Tumor-free margins and tumor relapse were not influenced by experience. In TLM, a learning curve could be observed for locally advanced tumors.