Relationship of depth of invasion to survival outcomes and patterns of recurrence for T3 oral tongue squamous cell carcinoma.

INTRODUCTION: Current research is elucidating how the addition of depth of invasion (DOI) to the 8th edition of the American Joint Committee on Cancer (AJCC) TNM staging for oral cavity squamous cell carcinoma influences its prognostic accuracy. However, there is limited research on survival in pT3N0M0 oral tongue SCC (OTSCC) patients when stratifying by DOI. OBJECTIVES: Determine 5-year overall survival (OS), and cancer-specific survival (CSS) for patients with pT3N0M0 oral OTSCC based on shallow DOI (<10 mm) and deep DOI (10-20 mm). METHODS: Retrospective review involving three tertiary care cancer centers in North America. cT3N0M0 OTSCC patients receiving primary surgical treatment from 2004 to 2018 were identified. Inclusion: age > 18 years old and confirmation of pT3N0M0 OTSCC on surgical pathology. Exclusion: patients undergoing palliative treatment or previous head and neck surgery/radiotherapy. Analysis comprised two groups: shallow pT3 (tumor diameter > 4 cm, DOI < 10 mm) and deep pT3 (DOI 10 mm-20 mm). RESULTS: One hundred and four patients with pT3N0M0 OTSCC were included. Mean age was 59.1 years (range: 18-80.74). Age, gender, and Charlson Comorbidity Index were similar between the two groups (p > 0.05). Recurrence, LVI, PNI, and positive margins were more common in deep T3 tumors (P < 0.05). 5-year OS (50% vs 26%, p = 0.006) and CSS (72% vs 24%, p = 0.005) were worse in deep pT3 tumors. Deep pT3 disease was an independent predictor of OS (p = 0.004) and CSS (p = 0.01) on Cox-Regression analysis. CONCLUSION: DOI is an independent predictor of poor survival in pT3N0M0 OTSCC patients. Consideration should be given to escalating adjuvant therapy for deep pT3N0M0 OTSCC patients.

0-7-21 hypofractionated palliative radiotherapy: an effective treatment for advanced head and neck cancers.

OBJECTIVE: We report our experience in providing palliative radiotherapy (RT) to patients with head and neck cancers (HNCs). Our hypofractionated regimen, "0-7-21", treats patients with 24 Gy in three fractions. METHODS: Patients, disease and response data were retrieved for candidates of 0-7-21 from 2005 to 2012. Primary end points included symptom and tumour size responses to RT based on response evaluation criteria in solid tumours (RECIST) guidelines. Secondary end points included progression-free survival (PFS) within the irradiated field, overall survival (OS) and symptomatic PFS (SPFS), calculated using Kaplan-Meier method and adverse events. Cox proportional hazards regression and logistic regression were used to investigate for prognostic factors. RESULTS: A total of 110 patients were included. Among the patients, 40% and 31% had complete response for symptoms and tumour size, respectively; 42% and 50% had partial response for symptoms and tumour size, respectively; and 15% had stability of symptoms and tumour size. Median 6-month OS was 51%, and PFS within the irradiated field was 39%. Planning target volume was predictive of OS (p < 0.001), PFS (p < 0.001) and SPFS (p < 0.005), while higher TNM stage was associated with poorer tumour response (p = 0.02). CONCLUSION: 0-7-21 is an effective and well-tolerated palliative RT regimen for patients with HNC. There was excellent symptom and local control with acceptable toxicity profile in these patients. ADVANCES IN KNOWLEDGE: This is the first study to describe the outcomes of 0-7-21 in treating advanced HNCs. The positive results suggest that 0-7-21 provides excellent palliation with minimal toxicity, with significantly less on-treatment time than current published palliative RT regimen.