ICHNO-ECHNO 2022 - Abstract Book

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ICHNO-ECHNO 2022

Materials and Methods Medical records of patients with pathologically proven non metastatic squamous cell carcinoma of the oropharynx treated with curative intent modern radiotherapy (helical tomotherapy or volumetric arc therapy) technique between 2009 and 2016 were retrospectively analyzed in a single institution. Patients were stratified according to the RTOG risk categories based on stage, p16 status and smoking history. Overall survival (OS) and progression free survival (PFS) were assessed using the Kaplan Meier method.Rates of toxicities per CTCAE v5 were reviewed. More specifically, risks of hospitalization, permanent gastrostomy, tracheostomy and radionecrosis were examined.Logistic regression was used to determine factors predictive of toxicity. Results 688 patients with oropharyngeal cancer were included.The majority were males (77%) and mean age at diagnosis was 61 (range 33-91). While 64% had smoked ≥ 10 pack-years, 25% were never smokers and 8% had smoked <10 pack-years. Primary cancer site was tonsil and base of tongue in 60% and 36% of cases, respectively. 59% had a p16 positive OPC , 8% had a p16 negative and the status was not known for 33% of patients. For p16+ve cases, 15%, 60% and 25% were classified as stage 1, 2 and 3 respectively according to AJCC 8 th edition. 34%, 15%, 29% were classified as low, intermediate, high risk according to RTOG risk categories while risk category was not identified in 28%. 81% received concurrent chemotherapy and 21% received induction chemotherapy. With a median follow up of 61 months, 3 and 8 year OS for the whole cohort were 88% and 79% respectively, while 3 and 8 year PFS for the whole cohort were 84% and 75% respectively. Factors that significantly affected OS and PFS were KPS performance status, smoking history, p16 status, RTOG risk group and type of concurrent chemotherapy. Rate of severe toxicities such as hospitalization during treatment, trachesotomy, gastrostomy and radionecrosis were 15%, 3.3%, 7.3% and 3.5% respectively. On logistic regression, patients with poor KPS , active alcohol consumption and concurrent chemotherapy were at increased risk of peri-treatment hospitalization. In terms of late toxicity, patients with high RTOG risk group and local recurrence were at higher risk of gastrostomy. In addition, p16 negative disease was associated with increased risk of radionecrosis.Patients with poor baseline KPS, local recurrence and use of concurrent chemotherapy were at higher risk of tracheostomy.

Conclusion Treatment of oropharyngeal cancer with modern radiotherapy results in 15% hospitalization rate and low overall rate of severe late toxicities. Factors associated with increased risk of severe toxicity includes poor KPS,active alcohol consumption,concurrent chemotherapy,local recurrence and p16-ve disease