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.

Skin elasticity as a measure of radiation fibrosis: is it reproducible and does it correlate with patient and physician-reported measures?

Current means of measuring RT-induced fibrosis are subjective. We evaluated the DermaLab suction cup system to measure objectively skin deflection as a surrogate for fibrosis. Sixty-nine patients with E-STS were treated with limb-sparing surgery and 50-66 Grays (Gy) of RT. Using a “scleroderma” DermaLab Suction Cup, the skin stiffness was measured by two clinicians. The National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) scale, the Musculoskeletal Tumor Rating Scale (MSTS) and Toronto Extremity Salvage Score (TESS) questionnaires were completed for each patient. Levels of agreement between measurers were estimated using the Kappa (κ) coefficient and the concordance correlation coefficient (CCC). All sixty-nine patients were included. The level of agreement between measurers for NCI-CTCAE grading was moderate (range κ = 0.41-0.59). The CCC for the elasticity measurements were higher, with CCC = 0.82 for fibrotic skin and CCC = 0.84 for normal skin. The elasticity measurements were significantly higher when MSTS scores were <30 and or TESS scores were <90. Suction Cup measurement of skin elasticity is more reproducible than CTCAE grading and shows promise in generating reproducible measurements for radiation-induced skin fibrosis. Furthermore, it correlates well with the MSTS and TESS.