{"entity":{"id":"extraprostatic-extension","kind":"term","name":"Extraprostatic extension and seminal vesicle invasion","aka":["extraprostatic extension","EPE","extracapsular extension","seminal vesicle invasion","SVI","pT3a","pT3b","capsular penetration","positive margin prostate"],"tldr":"Whether the cancer has grown out through the wall of the prostate (pT3a) or into the seminal vesicles behind it (pT3b). Both move the stage to T3, both make recurrence more likely, and after surgery both are read alongside whether the cancer reached the cut edge.","summary":"The prostate has no true capsule, so extraprostatic extension means tumour beyond the boundary of the gland into the surrounding fat or the nerve bundles, and it makes the tumour T3a; the eighth edition of TNM added microscopic bladder neck involvement to the same category. Invasion of the muscular wall of a seminal vesicle is T3b. Invasion into the apex of the prostate, or into but not beyond the capsule, is explicitly not T3 and stays T2. A tumour fixed to or invading the rectum, the external sphincter, the levator muscles or the pelvic wall is T4.\n\nOn a radical prostatectomy report these sit beside the surgical margin status, which is a different question: extension describes how far the cancer grew, a positive margin describes whether the surgeon's cut passed through cancer, and a man can have one without the other. Extraprostatic extension, seminal vesicle invasion and a positive margin are the findings that raise the chance of PSA returning after surgery and that drive the discussion about adjuvant or early salvage radiotherapy. In the Cambridge Prognostic Groups, any T3 puts a man in group 4 on its own, and T4 puts him in group 5 on its own.","asOf":"2026-09-25","links":[{"label":"Royal College of Pathologists G084: dataset for histopathology reports for prostatic carcinoma, version 4, October 2024","url":"https://www.rcpath.org/static/8cc88604-2c8d-4df4-a99542df41c102af/G084-dataset-for-histopathology-reports-for-prostatic-carcinoma.pdf"},{"label":"Brierley et al., International Journal of Cancer 2026: the 9th edition of the UICC TNM classification of malignant tumours, updates and rationale for change (prostate at section 10.1)","url":"https://doi.org/10.1002/ijc.70561"},{"label":"NICE NG131: prostate cancer, diagnosis and management (recommendations, including the Cambridge Prognostic Group table at 1.2.15)","url":"https://www.nice.org.uk/guidance/ng131/chapter/Recommendations"}],"tags":[],"related":["resection-margins","tnm-staging","prostatectomy","perineural-invasion","biochemical-recurrence"],"cancers":["prostate","prostate-high-risk","prostate-bcr"],"sections":["diagnostics","surgery"],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["tnm-prostate-cancer","cambridge-prognostic-group","biochemical-recurrence"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Pathology"},"route":"/terms/extraprostatic-extension/","neighbours":{"term":[{"id":"biochemical-recurrence","kind":"term","name":"Biochemical recurrence (BCR)","route":"/terms/biochemical-recurrence/"},{"id":"cambridge-prognostic-group","kind":"term","name":"Cambridge Prognostic Group (CPG 1 to 5)","route":"/terms/cambridge-prognostic-group/"},{"id":"perineural-invasion","kind":"term","name":"Perineural invasion (PNI)","route":"/terms/perineural-invasion/"},{"id":"prostatectomy","kind":"term","name":"Radical prostatectomy","route":"/terms/prostatectomy/"},{"id":"resection-margins","kind":"term","name":"Resection margins (R0 / R1 / R2)","route":"/terms/resection-margins/"},{"id":"tnm-staging","kind":"term","name":"TNM staging","route":"/terms/tnm-staging/"},{"id":"tnm-prostate-cancer","kind":"term","name":"TNM staging for prostate cancer, and what changed in the 9th edition","route":"/terms/tnm-prostate-cancer/"}],"cancer":[{"id":"prostate-bcr","kind":"cancer","name":"Biochemical recurrence of prostate cancer","route":"/cancers/prostate-bcr/"},{"id":"prostate-high-risk","kind":"cancer","name":"Localised prostate cancer, high and very high risk","route":"/cancers/prostate-high-risk/"},{"id":"prostate","kind":"cancer","name":"Prostate cancer","route":"/cancers/prostate/"}],"section":[{"id":"diagnostics","kind":"section","name":"Diagnostics & Biomarkers","route":"/fronts/diagnostics/"},{"id":"surgery","kind":"section","name":"Surgery & Interventional","route":"/fronts/surgery/"}]}}