Subramaniam N, et al. - As a depth of invasion (DOI) >10 mm is classified as pT3, representing a locally advanced tumour requiring postoperative radiotherapy (PORT), according to the eighth edition of the AJCC Cancer Staging Manual (AJCC8), researchers here investigated the evidence regarding the influence of PORT on loco-regional control or survival when node-negative. They studied two cohorts of patients: patients classified as pT3N0 by the seventh edition of the AJCC manual (AJCC7), with DOI >10 mm and a tumour diameter >4 cm (17 patients who received PORT); and patients classified as pT1N0 and pT2N0 by AJCC7, with DOI >10 mm and a tumour diameter <4 cm (55 patients who did not receive PORT). Data provide no firm justification for the routine administration of PORT for patients with a DOI >10 mm in the absence of other risk features such as nodal disease or close margins.