Khorana score
Risk of chemotherapy-associated VTE in ambulatory cancer patients
- Derived in US outpatient cohort
Sources last checked: 2026-10-13
Khorana score
Risk of chemotherapy-associated VTE in ambulatory cancer patients
Assessed before starting a new chemotherapy regimen. Discrimination is modest (C-statistic 0.7) and poor in some tumour types (e.g. lung); brain tumours and myeloma are not covered. The Vienna CATS-MICA model adds D-dimer.
Interpretation
| 0 — low risk | Symptomatic VTE 0.3–0.8 % over a median 2.5 months (validation / derivation). |
|---|---|
| 1–2 — intermediate risk | VTE 1.8–2 % over a median 2.5 months. A score ≥ 2 was the entry criterion of the AVERT and CASSINI prophylaxis trials. |
| ≥ 3 — high risk | VTE 6.7–7.1 % over a median 2.5 months (high-risk category of the derivation study). |
What is the Khorana score?
The Khorana score predicts symptomatic VTE in ambulatory cancer patients starting chemotherapy from tumour site, three blood counts and BMI. Khorana and colleagues derived it in 2,701 patients and validated it in 1,365 (Blood 2008). It became the selection tool for the AVERT and CASSINI trials of primary prophylaxis with apixaban and rivaroxaban (Khorana ≥ 2).
When to use it
- Before starting a new chemotherapy regimen in an ambulatory patient with cancer.
- Identifying candidates for primary thromboprophylaxis with a DOAC or LMWH.
- Counselling patients about VTE symptoms when risk is high.
When not to use it
- Hospitalised cancer patients (use Padua or another inpatient model).
- Primary brain tumours and multiple myeloma, which were not adequately represented.
- Patients with a high bleeding risk, where the score alone must not drive anticoagulation.
How it is calculated
| Criterion | Points |
|---|---|
| Site of cancer | |
| Other sites (e.g. breast, colorectal, prostate) | 0 |
| High risk: lung, lymphoma, gynaecological, bladder, testicular | 1 |
| Very high risk: stomach, pancreas | 2 |
| Pre-chemotherapy platelet count ≥ 350 × 10⁹/L | +1 |
| Haemoglobin < 100 g/L or use of red-cell growth factors | +1 |
| Pre-chemotherapy leukocyte count > 11 × 10⁹/L | +1 |
| BMI ≥ 35 kg/m² | +1 |
Clinical pearls and limitations
- Assessed before starting a new chemotherapy regimen. Discrimination is modest (C-statistic 0.7) and poor in some tumour types (e.g. lung); brain tumours and myeloma are not covered. The Vienna CATS-MICA model adds D-dimer.
- Blood counts are pre-chemotherapy values.
- Haemoglobin is in g/L: < 100 g/L (< 10 g/dL), or any use of erythropoiesis-stimulating agents.
- Lung cancer scores 1 point, but later cohorts report weaker discrimination in some tumour types — interpret per tumour entity.
- The Vienna CATS/MICA model reaches similar performance with only tumour site and D-dimer.
Frequently asked questions
What Khorana score is high risk?
The original paper defines ≥ 3 as high risk (6.7–7.1 % VTE in about 2.5 months). Prophylaxis trials (AVERT, CASSINI) enrolled patients with ≥ 2.
Which cancers score 2 points?
Stomach and pancreas. Lung, lymphoma, gynaecological, bladder and testicular cancers score 1 point.
Does a Khorana score of 0 mean no VTE risk?
No. VTE still occurred in 0.3–0.8 % within 2.5 months; cancer itself raises baseline risk.
Evidence and guidelines
- Primary source: Khorana AA et al. Development and validation of a predictive model for chemotherapy-associated thrombosis. Blood 2008;111(10):4902-4907.
- Carrier M et al. Apixaban to prevent VTE in patients with cancer (AVERT; Khorana ≥ 2). N Engl J Med 2019;380:711-719.
- Khorana AA et al. Rivaroxaban for thromboprophylaxis in high-risk ambulatory patients with cancer (CASSINI; Khorana ≥ 2). N Engl J Med 2019;380:720-728.
- AWMF S2k 065-002 (2023), section 6.3 (Khorana-Score ≥ 2 in Prophylaxestudien).
Have a follow-up question?
Medelix answers clinical questions from current guidelines and studies — every statement with its source.
Ask Medelix about the Khorana scoreRelated calculators
- Vienna CATS score (CATS/MICA model)6-month risk of cancer-associated VTE from tumour site and D-dimer
- Padua Prediction ScoreVTE risk in hospitalised medical patients — who needs thromboprophylaxis
- IMPROVE bleeding risk scoreIn-hospital bleeding risk in acutely ill medical patients before thromboprophylaxis
- Body mass indexWeight-for-height index
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