{"entity":{"id":"bwh-staging-cscc","kind":"term","name":"The Brigham and Women's Hospital staging system, and why squamous cell carcinoma has two","aka":["BWH staging","Brigham and Women's Hospital staging","BWH T stage","BWH T2b","BWH T2a","BWH T3","alternative tumour staging cSCC","cSCC risk stratification","Baum risk bands"],"tldr":"The anatomical staging systems put almost every squamous cell carcinoma in one or two categories, so they cannot pick out the few that will spread. A Boston group built an alternative that counts four risk factors instead of measuring the tumour, and it finds the same poor outcomes in a group half the size. Britain uses the anatomical system and treats the Boston one as evidence, not policy.","summary":"**The problem it was built for.** In a cohort of 256 primary high-risk squamous cell carcinomas, outcomes for AJCC stages T2 to T4 were statistically indistinguishable, because fewer than 2 percent of the cohort reached T3 or T4, which then required bone invasion. The result was that 83 percent of nodal metastases and 92 percent of deaths happened in stage T2 (Jambusaria-Pahlajani 2013). A stage that contains almost everyone and almost every bad outcome cannot be used to decide who needs extra treatment.\n\n**How it works.** The alternative counts four independent risk factors: poor differentiation, perineural invasion, tumour diameter of 2 cm or more, and invasion beyond the subcutaneous fat. No factors is T1, one factor is T2a, two or three factors is T2b, and four factors or bone invasion is T3. In the derivation cohort T2b tumours were only 19 percent of cases but accounted for 72 percent of nodal metastases and 83 percent of deaths from the disease.\n\n**How it holds up.** In 1,818 primary tumours from 2000 to 2009, AJCC and UICC T3 and T4 were indistinct, with overlapping confidence intervals, and were very rare, 0.3 percent and 3 percent of the cohort respectively; most poor outcomes fell in the low stages, 86 percent for AJCC and 70 percent for UICC. Under the Boston system only 5 percent of tumours were high stage, T2b or T3, and they carried 60 percent of poor outcomes, 70 percent of nodal metastases and 83 percent of disease-specific deaths. Ten-year cumulative incidences in low-stage tumours were 1.4 percent local recurrence, 0.6 percent nodal metastasis and 0.2 percent death from the cancer; in high-stage tumours, 24 percent, 24 percent and 16 percent (Karia 2014). Against the eighth edition, which was a real improvement on the seventh, the comparison is closer but the same in shape: AJCC 8 T3 and T4 were 18 percent of 680 head and neck tumours and the Boston T2b and T3 were 9 percent, and both captured about 71 percent of metastases and 85 to 92 percent of deaths; the Boston system had higher specificity, 93 percent, and higher positive predictive value, 30 percent, and better C statistics for nodal metastasis and disease-specific death, with no difference for local recurrence or overall survival (Ruiz 2019). The authors' conclusion was that AJCC 8's failure to separate T2 from T3 leaves a 23 percent group at significant risk, too large for routine nodal staging or adjuvant treatment.\n\n**Where Britain stands.** UK reports stage against UICC (see `tnm-skin-carcinoma`) and stratify risk separately, and the Royal College of Pathologists has taken an explicit and dissenting position on the risk bands built on the Boston system. It sets out its own numerical thresholds: an adverse consequence rate, counting recurrence, nodal spread, systemic spread or death, below 5 percent is low risk, 5 to 20 percent is high risk and over 20 percent is very high risk; and any squamous cell carcinoma under 20 mm across or under 2 mm thick with no additional factors is, in its words, of negligible rather than merely low risk. A proposal derived from the Boston system calls 5 to 20 percent intermediate and over 20 percent high. The RCPath judges that restricting the word high risk to over 20 percent is inappropriate, that those intermediate cases are better called high risk and the high-risk ones very high risk, and that the proposal 'could potentially leave some serious intermediate cases under-rated in terms of risk and thereby receive inappropriate clinical management' (G124). Its final position is that risk stratification is better done by the treating clinician or the skin cancer multidisciplinary team than recorded as a core item in a pathology report at all.","asOf":"2026-09-25","wikipedia":"https://en.wikipedia.org/wiki/Squamous-cell_carcinoma_of_the_skin","links":[{"label":"Jambusaria-Pahlajani et al., JAMA Dermatology 2013;149:402 to 410: evaluation of AJCC tumour staging for cutaneous squamous cell carcinoma and a proposed alternative tumour staging system (256 primary high-risk tumours; the derivation of the Brigham and Women's Hospital system)","url":"https://doi.org/10.1001/jamadermatol.2013.2456"},{"label":"Karia et al., Journal of Clinical Oncology 2014;32:327 to 334: evaluation of AJCC, UICC and Brigham and Women's Hospital tumour staging for cutaneous squamous cell carcinoma (1,818 primary tumours, 2000 to 2009)","url":"https://doi.org/10.1200/jco.2012.48.5326"},{"label":"Karia et al., JAMA Dermatology 2018;154:175 to 181: comparison of tumour classifications for cutaneous squamous cell carcinoma of the head and neck in the 7th versus the 8th edition of the AJCC staging manual (680 tumours in 459 patients)","url":"https://doi.org/10.1001/jamadermatol.2017.3960"},{"label":"Ruiz, Karia, Besaw and Schmults, JAMA Dermatology 2019;155:819 to 825: performance of the AJCC staging manual 8th edition versus the Brigham and Women's Hospital tumour classification system for cutaneous squamous cell carcinoma","url":"https://doi.org/10.1001/jamadermatol.2019.0032"},{"label":"Royal College of Pathologists G124: dataset for histopathological reporting of primary invasive cutaneous squamous cell carcinoma and regional lymph nodes, version 4, February 2019 (Slater and Barrett)","url":"https://www.rcpath.org/resourceLibrary/g124datasetsquamous-pdf.html"}],"tags":[],"related":["cancer-stage","tnm-staging","perineural-invasion","prognosis"],"cancers":["cutaneous-scc","advanced-cutaneous-scc","skin-cancer"],"sections":["diagnostics"],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["tnm-skin-carcinoma","skin-cancer-high-risk-features","cscc-subtype-and-grade"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":["Why two systems is the honest answer rather than a failure. They are answering different questions. An anatomical stage is built to be recorded by every registry in the world from a measurement anybody can take, and to be comparable across decades and countries. A risk classification is built to decide what to do about one tumour in front of one person this week. The first cannot be abandoned without losing every trend line; the second cannot be abandoned without treating the wrong people. Any source presenting one of them as the correct staging of squamous cell carcinoma is answering only half the question.","All these numbers come from one hospital. The derivation and both validations are cohorts from a single academic centre in Boston, referred there because their tumours were difficult, and the papers themselves call for population-based validation. Rates of metastasis and death in an unselected population are lower than in any of these cohorts. What transfers is the ranking, which tumours are dangerous, rather than the absolute percentages."],"category":"Pathology"},"route":"/terms/bwh-staging-cscc/","neighbours":{"term":[{"id":"tnm-skin-carcinoma","kind":"term","name":"How skin carcinoma is staged in Britain: UICC TNM, and why it is not the American system","route":"/terms/tnm-skin-carcinoma/"},{"id":"perineural-invasion","kind":"term","name":"Perineural invasion (PNI)","route":"/terms/perineural-invasion/"},{"id":"prognosis","kind":"term","name":"Prognosis","route":"/terms/prognosis/"},{"id":"cancer-stage","kind":"term","name":"Stage","route":"/terms/cancer-stage/"},{"id":"cscc-subtype-and-grade","kind":"term","name":"The subtype and grade on a cutaneous squamous cell carcinoma report","route":"/terms/cscc-subtype-and-grade/"},{"id":"tnm-staging","kind":"term","name":"TNM staging","route":"/terms/tnm-staging/"},{"id":"skin-cancer-high-risk-features","kind":"term","name":"What makes a skin cancer high risk: the UK feature lists","route":"/terms/skin-cancer-high-risk-features/"}],"cancer":[{"id":"advanced-cutaneous-scc","kind":"cancer","name":"Advanced cutaneous squamous cell carcinoma","route":"/cancers/advanced-cutaneous-scc/"},{"id":"cutaneous-scc","kind":"cancer","name":"Cutaneous squamous cell carcinoma","route":"/cancers/cutaneous-scc/"},{"id":"skin-cancer","kind":"cancer","name":"Skin cancer (all types)","route":"/cancers/skin-cancer/"}],"section":[{"id":"diagnostics","kind":"section","name":"Diagnostics & Biomarkers","route":"/fronts/diagnostics/"}]}}