Reasoning GP · Algorithm · 1-page summary
Abnormal tumour markers in primary care
For: adults with a raised tumour marker, or when deciding whether to request one. Not for: screening people without symptoms, or children (paediatric cancer referral pathway). Raised PSA detail: high PSA algorithm. Known cancer: the specialist's written surveillance plan.
Core rule: tumour markers rarely diagnose cancer in isolation. Symptoms, examination, imaging or FIT and the NG12 pathway decide referral; an isolated raised CEA, CA19-9, AFP or LDH is not a referral criterion, and a normal marker never overrides persistent symptoms.
0Act today — before interpreting any marker
- Positive pregnancy test with bleeding, or persistent hCG after a pregnancy event (possible ectopic or GTD) → exclude ectopic, assess haemodynamic stability → Same-day early pregnancy / gynaecology service or GTD centre. Collapse or heavy bleeding → 999
- Abnormal blood film, blasts, severe cytopenias or acutely unwell → Same-day haematology discussion.
- New liver lesion, suspicious ultrasound, progressive AFP rise or unexplained deterioration in chronic liver disease → Urgent hepatology / hepatobiliary discussion; imaging via the local liver pathway.
- Ascites or unexplained pelvic / abdominal mass → Suspected cancer pathway referral; do not wait for CA125.
1Triage the marker — does it have a primary-care role?
| Marker | Use in primary care |
|---|---|
| PSA | Possible symptoms (LUTS, erectile dysfunction, visible haematuria), or an informed request (50+ after counselling: may have it) |
| CA125 | Aged 40+, persistent or frequent ovarian symptoms |
| FIT, not CEA | Colorectal symptoms; refer if ≥10 µg Hb/g faeces |
| AFP · hCG | AFP: HCC surveillance via hepatology. hCG: pregnancy, GTD, germ-cell |
| Specialist only | CEA, CA19-9, CA15-3, chromogranin A, NSE, CYFRA 21-1, S100/LDH, thyroglobulin — not for diagnosis |
2Screen — NG12 routes
- Malignant-feeling prostate on DRE, any PSA → Suspected cancer urology.
- PSA above threshold with possible symptoms (40–49 >2.5; 50–59 >3.5; 60–69 >4.5; 70–79 >6.5 ng/mL; <40 or 80+ judgement) → Suspected cancer referral (discuss preferences, comorbidities).
- CA125 at or above threshold, aged 40+ (40–49 ≥35; 50–59 ≥31; 60–69 ≥24; 70–79 ≥25; 80+ ≥31 IU/mL) → Urgent direct-access ultrasound abdomen and pelvis; suggests ovarian cancer → suspected cancer. ≤39: not CA125 alone; consider urgent ultrasound.
- Colorectal symptoms → FIT ≥10 → Suspected cancer. Rectal or anal mass, anal ulceration → refer without FIT. Negative or unavailable FIT with ongoing concern → do not delay.
- Possible leukaemia → consider FBC and film within 48 h. Unexplained lymphadenopathy or splenomegaly → consider suspected cancer referral.
3Assess
☐ Abdomen, pelvis, DRE, nodes, liver ☐ Result, units, laboratory range, trend ☐ PSA: not during UTI or prostatitis; note ejaculation, exercise, retention, catheter, instrumentation, finasteride
Not in primary care: RMI I, PSA velocity / density / free-to-total, standalone CA19-9, a bone scan solely for PSA >10.
4Classify — only if blocks 0–2 are negative
- Benign rise — CA125: menstruation, pregnancy, endometriosis, fibroids, PID, liver disease, heart failure. CEA: smoking, COPD, IBD. CA19-9: biliary obstruction, pancreatitis. AFP: pregnancy, hepatitis.
- PSA with infection or confounder — treat, repeat under optimal conditions; still above threshold → suspected cancer referral.
- Raised CA125, normal ultrasound — investigate other causes, safety-net. New ascites, mass or worsening → suspected cancer.
- Known cancer on surveillance — follow the written plan; a rising marker → contact the treating team.
- Uncertain — say so; record who reviews the result and when.
5Treat today — only these
- Suspected prostatitis: antibiotic for 14 days, then review (NG110); repeat PSA once resolved.
- LUTS awaiting urology: tamsulosin 400 micrograms once daily. Doses: NICE/SPC, BNF, local formulary.
- Anxiety: “An elevated PSA does not mean cancer — it means we need to investigate further”; give a clear timeline.
6Refer routinely
- Persistent symptoms with a non-suggestive ultrasound, or suspected benign gynaecological cause → gynaecology per local pathway.
- Cirrhosis, or hepatitis B with significant fibrosis → 6-monthly ultrasound ± AFP via hepatology surveillance; check it happens.
- Colorectal cancer follow-up: CEA at least every 6 months for 3 years (NG151), per the oncology plan.
- Known BRCA2 variant (high risk) → targeted surveillance via specialist or genetics pathways, not population screening; strong family history → consider clinical genetics.
7Never reassure by
- A normal CA125 or low RMI when symptoms persist.
- A normal PSA when the prostate feels malignant.
- A negative FIT when clinical concern remains.
- A normal AFP in cirrhosis with a new liver lesion.
- A bowel screening result in a patient with symptoms.
- Never screen people without symptoms using markers.
8Safety-net — say it, then document it
999 “Call 999 for collapse, fainting, heavy bleeding or severe tummy pain if you are pregnant.” Same-day “Contact us or NHS 111 today for any bleeding with a positive pregnancy test, or new bruising, bleeding, fever or feeling very unwell while your blood results are awaited.”
Review: agree a date (NG12: a time frame agreed with the patient); contact us before it if symptoms recur, persist or worsen, or the appointment or result has not arrived when expected.
✓Safe to leave primary care only if — all five, documented
No block 0–2 row applies
Symptoms, examination and confounders recorded
Benign cause named, or uncertainty stated
Result owner, repeat or review date set; plan if not attended
Safety-net given and documented
Summary of the full Reasoning GP tumour markers algorithm, which holds marker-by-marker detail, surveillance and evidence. Sources: NICE NG12 (updated April 2026), CG122, NG131, NG151, NG50, CG165, NG110; RCOG Green-top 38; UK National Screening Committee; local FIT and suspected-cancer pathways. Clinical reference — follow local pathways and check doses: NICE/SPC, BNF.