The Evolution of Technology in the Management of Early Stage (T1) Cancer of the Glottic Larynx, an Institutional Review of Radiation Therapy Outcomes |Biomedgrid

Purpose: This single institution, retrospective cohort study was undertaken to evaluate the impact of evolving radiation therapy (RT) treatment technology on the long-term outcomes and patterns of failure for patients with early stage, T1, squamous cell cancer of the larynx. Materials and methods: All patients with T1N0 squamous cell cancer of the larynx that underwent radical RT from January 2008 to December 2018 were included. The planning and delivery of radiation, 2-dimensional RT vs IMRT or VMAT, as well as patient factors were reviewed in the context of local disease control. Results: A total of 171 Patients were eligible for inclusion in the analysis. The median age was 70 years (range of 38-91 years), and just over 90% (90.6%) of the cohort were male. While all patients were staged as having T1 disease, a smaller proportion had more detailed assignments of T1a (38 or 23.3%), or T1b (23 or 14.1%). The majority of patients were treated with 50-51 Gy in 20 daily fractions over four weeks. After a median follow up of over five years, there were only 11 patients (6.4%) that had demonstrated local regional failure, most occurring within the first two years of follow up, and in a multivariate model, only age was a prognostic factor for local control (p=0.013), whereas RT technique specifically was not. Conclusion: Single-modality RT provides an excellent and effective treatment for T1 glottic cancer. A shift to conformal 3-D planning and treatment delivery to minimize radiation dose to surrounding normal tissues, has not resulted in a significant change to rates of local failure. The majority of local failures have occurred within the first 2 years after RT. Prospective comparative measures of toxicity and functional preservation seem unlikely to be measured given the shift in the routine delivery of RT.