{"entity":{"id":"cup-favourable-subsets","kind":"cancer","name":"Cancer of unknown primary, favourable subsets","aka":["Favourable-risk CUP","Treatable CUP subsets","CUP with a presumed primary","Specific CUP syndromes"],"tldr":"Favourable subsets of cancer of unknown primary are the roughly one in five cases where the pattern of spread, the microscope appearance or blood markers point strongly to a particular cancer even though no primary can be found. They are treated as that cancer would be, for example breast cancer for a woman with cancer only in armpit nodes, and many are curable or controllable for years.","summary":"Cancer of unknown primary is a metastatic cancer whose origin cannot be found despite a full work-up. Within it, decades of clinical observation identified subsets that behave like, and respond to treatment for, a specific cancer. The ESMO 2023 guideline lists them: women with adenocarcinoma confined to axillary nodes (treated as breast cancer with axillary dissection, breast radiotherapy or mastectomy and systemic therapy); women with serous papillary carcinoma of the peritoneum (treated as ovarian cancer with cytoreductive surgery and carboplatin-paclitaxel); squamous cell carcinoma in cervical nodes (treated as head and neck cancer, with HPV or EBV testing, neck dissection and chemoradiotherapy) or in inguinal nodes (treated with node dissection and radiotherapy as anogenital cancer); young men with poorly differentiated carcinoma in a midline distribution or raised markers (treated as extragonadal germ cell tumour with cisplatin-based chemotherapy); men with bone metastases and raised PSA (treated as prostate cancer); neuroendocrine carcinoma of unknown primary (treated as extrapulmonary neuroendocrine carcinoma or, if well differentiated, as a neuroendocrine tumour); adenocarcinoma with a colorectal immunoprofile (CK20 and CDX2 positive, CK7 negative; treated as colorectal cancer); a single resectable metastasis (treated with surgery or radiotherapy); and renal-like carcinoma.\n\nRecognising these patterns depends on a disciplined work-up: histology with a directed immunohistochemistry panel, CT of chest, abdomen and pelvis, mammography or breast MRI and gynaecological examination in women, PSA in men, alpha-fetoprotein and hCG in young patients, and PET-CT in cervical node squamous carcinoma and single-site disease. Gene-expression and DNA-methylation tissue-of-origin classifiers can assign a likely primary in most cases, but two randomised trials (GEFCAPI 04 and a Japanese trial) found that classifier-directed site-specific therapy did not beat empirical chemotherapy in unfavourable disease, so the classifiers are used to support rather than replace clinical judgement. Because the subsets are treated as their presumed cancer, their prognosis approaches that of the corresponding metastatic or node-positive disease, which is why every patient with CUP should be reviewed against the list before empirical chemotherapy is started.","asOf":"2026-09-18","wikipedia":"https://en.wikipedia.org/wiki/Cancer_of_unknown_primary_origin","links":[{"label":"ESMO CUP guideline 2023","url":"https://doi.org/10.1016/j.annonc.2022.11.013"},{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Cancer_of_unknown_primary_origin"}],"tags":["subtype-page","site-agnostic"],"related":["cup-unfavourable","cancer-of-unknown-primary","extragonadal-germ-cell-tumour","extrapulmonary-nec"],"cancers":[],"sections":[],"technologies":["histopathology-ihc","cgp","methylation-profiling","pet-ct","ct","imrt-igrt","sbrt","germ-cell-tumour-markers"],"targets":[],"drugs":["carboplatin","paclitaxel","cisplatin","etoposide","platinum-etoposide","octreotide-lanreotide","lutathera"],"companies":[],"institutions":[],"pathways":[],"terms":["ihc","tumour-markers","primary-tumour","hpv-p16","chemoradiation","lymphadenectomy","debulking"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":["paper-esmo-cancer-of-unknown-primary-guideline-ann-oncol-2023","paper-hayashi-site-specific-vs-empirical-chemotherapy-cup-jco-2019"],"journals":[],"dependsOn":[],"notes":[],"group":"other","burden":"About a fifth of cancers of unknown primary fall into a recognised favourable subset; these patients live far longer than the rest because their disease can be treated as the cancer it most resembles.","subtypes":["Adenocarcinoma confined to axillary nodes in a woman (treated as breast cancer)","Serous papillary peritoneal carcinoma in a woman (treated as ovarian cancer)","Squamous cell carcinoma in cervical nodes (treated as head and neck cancer)","Squamous cell carcinoma in inguinal nodes (treated as anogenital cancer)","Poorly differentiated midline carcinoma in a young man (treated as extragonadal germ cell tumour)","Neuroendocrine carcinoma of unknown primary","Adenocarcinoma with a colorectal immunoprofile (CK20 and CDX2 positive, CK7 negative)","Men with bone metastases and raised PSA (treated as prostate cancer)","Single resectable metastasis of unknown primary"],"biomarkers":["Directed immunohistochemistry panel (CK7, CK20, CDX2, GATA3, PAX8, TTF-1, NKX3.1, p16, SOX10)","Serum PSA (men), alpha-fetoprotein and hCG (young patients), CA-125 (women)","HPV (p16) and EBV testing in cervical node squamous carcinoma","Oestrogen receptor and HER2 in axillary node adenocarcinoma","Tissue-of-origin classifier (gene expression or methylation, supportive)","Ki-67 and neuroendocrine markers where neuroendocrine carcinoma is suspected"],"standardOfCare":[{"setting":"Work-up","approach":"Histology with directed immunohistochemistry, CT of chest, abdomen and pelvis, sex-specific examinations and tumour markers, PET-CT for cervical node squamous carcinoma and single-site disease.","refs":["histopathology-ihc","ihc","ct","pet-ct","tumour-markers","germ-cell-tumour-markers"],"guideline":{"version":"ESMO Clinical Practice Guideline on cancer of unknown primary 2023","url":"https://doi.org/10.1016/j.annonc.2022.11.013"}},{"setting":"Axillary node adenocarcinoma in a woman","approach":"Treat as node-positive breast cancer: axillary dissection, breast radiotherapy or mastectomy, systemic therapy by receptor status.","refs":["lymphadenectomy","imrt-igrt"],"guideline":{"version":"ESMO Clinical Practice Guideline on cancer of unknown primary 2023","url":"https://doi.org/10.1016/j.annonc.2022.11.013"}},{"setting":"Peritoneal serous carcinoma in a woman","approach":"Treat as advanced ovarian cancer: cytoreductive surgery and carboplatin-paclitaxel with maintenance as indicated.","refs":["carboplatin","paclitaxel","debulking"],"guideline":{"version":"ESMO Clinical Practice Guideline on cancer of unknown primary 2023","url":"https://doi.org/10.1016/j.annonc.2022.11.013"}},{"setting":"Cervical node squamous carcinoma","approach":"Treat as head and neck cancer: HPV and EBV testing, neck dissection or chemoradiotherapy with cisplatin.","refs":["cisplatin","imrt-igrt","chemoradiation","hpv-p16"],"guideline":{"version":"ESMO Clinical Practice Guideline on cancer of unknown primary 2023","url":"https://doi.org/10.1016/j.annonc.2022.11.013"}},{"setting":"Midline poorly differentiated carcinoma in a young man","approach":"Treat as extragonadal germ cell tumour with cisplatin-based combination chemotherapy.","refs":["cisplatin","etoposide","germ-cell-tumour-markers"],"guideline":{"version":"ESMO Clinical Practice Guideline on cancer of unknown primary 2023","url":"https://doi.org/10.1016/j.annonc.2022.11.013"}},{"setting":"Neuroendocrine carcinoma of unknown primary","approach":"Platinum-etoposide as for extrapulmonary neuroendocrine carcinoma; somatostatin analogues and radioligand therapy for well-differentiated tumours.","refs":["platinum-etoposide","octreotide-lanreotide","lutathera"],"guideline":{"version":"ESMO Clinical Practice Guideline on cancer of unknown primary 2023","url":"https://doi.org/10.1016/j.annonc.2022.11.013"}},{"setting":"Single metastasis","approach":"Resection or stereotactic radiotherapy with curative intent.","refs":["sbrt"],"guideline":{"version":"ESMO Clinical Practice Guideline on cancer of unknown primary 2023","url":"https://doi.org/10.1016/j.annonc.2022.11.013"}}],"stateOfArt":["Treating a favourable subset as its presumed cancer gives outcomes close to that cancer's.","Immunohistochemistry panels assign most tumours to a lineage within days.","Tissue-of-origin classifiers support but do not replace the clinical subsets."],"history":[{"year":1980,"title":"Cisplatin-based chemotherapy cures young men with midline poorly differentiated carcinoma, defining the first favourable subset","refs":["cisplatin"]},{"year":1990,"title":"Axillary node adenocarcinoma in women recognised as occult breast cancer","refs":[]},{"year":2010,"title":"Gene-expression tissue-of-origin classifiers reach clinical use","refs":[]},{"year":2019,"title":"GEFCAPI 04: classifier-directed therapy does not beat empirical chemotherapy","refs":[]},{"year":2023,"title":"ESMO guideline codifies the favourable subsets and their treatment","refs":["histopathology-ihc"]}],"pipeline":["cgp","methylation-profiling","liquid-biopsy"],"openProblems":["Some favourable subsets rest on small series decades old.","Whether a tissue-of-origin classifier should ever override the clinical picture is unsettled.","Patients outside specialist centres are often given empirical chemotherapy without the subset review.","Biopsy material is frequently too small for the full immunohistochemistry panel and sequencing."],"parent":"cancer-of-unknown-primary"},"route":"/cancers/cup-favourable-subsets/","neighbours":{"cancer":[{"id":"cancer-of-unknown-primary","kind":"cancer","name":"Cancer of unknown primary (CUP)","route":"/cancers/cancer-of-unknown-primary/"},{"id":"cup-unfavourable","kind":"cancer","name":"Cancer of unknown primary, unfavourable (adenocarcinoma and poorly differentiated carcinoma)","route":"/cancers/cup-unfavourable/"},{"id":"extragonadal-germ-cell-tumour","kind":"cancer","name":"Extragonadal germ cell tumour","route":"/cancers/extragonadal-germ-cell-tumour/"},{"id":"extrapulmonary-nec","kind":"cancer","name":"Extrapulmonary neuroendocrine carcinoma","route":"/cancers/extrapulmonary-nec/"}],"technology":[{"id":"germ-cell-tumour-markers","kind":"technology","name":"AFP, hCG and LDH in germ cell tumours (IGCCCG risk groups)","route":"/technologies/germ-cell-tumour-markers/"},{"id":"cgp","kind":"technology","name":"Comprehensive genomic profiling","route":"/technologies/cgp/"},{"id":"ct","kind":"technology","name":"CT (computed tomography)","route":"/technologies/ct/"},{"id":"methylation-profiling","kind":"technology","name":"DNA methylation profiling","route":"/technologies/methylation-profiling/"},{"id":"histopathology-ihc","kind":"technology","name":"Histopathology & immunohistochemistry","route":"/technologies/histopathology-ihc/"},{"id":"imrt-igrt","kind":"technology","name":"IMRT / IGRT (modern external beam)","route":"/technologies/imrt-igrt/"},{"id":"liquid-biopsy","kind":"technology","name":"Liquid biopsy (ctDNA)","route":"/technologies/liquid-biopsy/"},{"id":"pet-ct","kind":"technology","name":"PET/CT","route":"/technologies/pet-ct/"},{"id":"sbrt","kind":"technology","name":"SBRT / SABR (stereotactic radiotherapy)","route":"/technologies/sbrt/"}],"drug":[{"id":"carboplatin","kind":"drug","name":"Carboplatin","route":"/drugs/carboplatin/"},{"id":"cisplatin","kind":"drug","name":"Cisplatin","route":"/drugs/cisplatin/"},{"id":"etoposide","kind":"drug","name":"Etoposide","route":"/drugs/etoposide/"},{"id":"lutathera","kind":"drug","name":"Lutetium-177 dotatate","route":"/drugs/lutathera/"},{"id":"paclitaxel","kind":"drug","name":"Paclitaxel / nab-paclitaxel","route":"/drugs/paclitaxel/"},{"id":"platinum-etoposide","kind":"drug","name":"Platinum + etoposide (EP / CE)","route":"/drugs/platinum-etoposide/"},{"id":"octreotide-lanreotide","kind":"drug","name":"Somatostatin analogues (octreotide, lanreotide)","route":"/drugs/octreotide-lanreotide/"}],"term":[{"id":"chemoradiation","kind":"term","name":"Chemoradiation (chemoradiotherapy, CRT)","route":"/terms/chemoradiation/"},{"id":"debulking","kind":"term","name":"Debulking (cytoreductive surgery)","route":"/terms/debulking/"},{"id":"hpv-p16","kind":"term","name":"HPV-positive (p16) head and neck cancer","route":"/terms/hpv-p16/"},{"id":"ihc","kind":"term","name":"Immunohistochemistry (IHC)","route":"/terms/ihc/"},{"id":"lymphadenectomy","kind":"term","name":"Lymphadenectomy (lymph node dissection)","route":"/terms/lymphadenectomy/"},{"id":"primary-tumour","kind":"term","name":"Primary tumour","route":"/terms/primary-tumour/"},{"id":"tumour-markers","kind":"term","name":"Tumour markers (CEA, LDH, chromogranin, thyroglobulin)","route":"/terms/tumour-markers/"}],"paper":[{"id":"paper-esmo-cancer-of-unknown-primary-guideline-ann-oncol-2023","kind":"paper","name":"Cancer of unknown primary: ESMO Clinical Practice Guideline for diagnosis, treatment and follow-up","route":"/key-papers/paper-esmo-cancer-of-unknown-primary-guideline-ann-oncol-2023/"},{"id":"paper-hayashi-site-specific-vs-empirical-chemotherapy-cup-jco-2019","kind":"paper","name":"Randomised phase 2 trial of site-specific treatment based on gene expression profiling versus carboplatin and paclitaxel in cancer of unknown primary","route":"/key-papers/paper-hayashi-site-specific-vs-empirical-chemotherapy-cup-jco-2019/"}]}}