Ebrahimi A, et al. - In this multi-institutional international cohort, researchers examined 1,409 patients treated between 1990 and 2011 for oral small oral squamous cell carcinomas (SCC) ≤4 cm to confirm if the depth of invasion (DOI) could be an independent indication for postoperative radiotherapy (PORT) SCC. They found no relationship between DOI and disease-specific survival in candidates without other adverse factors (nodal metastases; close [<5 mm] or involved margins) with an excellent prognosis. A 5-year disease-specific mortality of 10% with DOI ≥10 mm, 8% with DOI 5-10 mm, and 6% with DOI <5 mm indicated an absolute risk difference of only 4%, in the absence of PORT.