# Oncotype DX

Source: https://onco.cc/drugs/oncotype-dx/  
OnCo record `oncotype-dx` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A 21-gene test that tells most women with early hormone-positive breast cancer whether they can safely skip chemotherapy.

## Summary

Oncotype DX is a gene-expression assay that measures 16 cancer-related and 5 reference genes by RT-PCR in tumour tissue to give a recurrence score estimating both the risk of distant recurrence and the likely benefit from chemotherapy in early hormone-positive, HER2-negative breast cancer. TAILORx (2018) showed that women with a score of 25 or below, if over 50, derive no benefit from adding chemotherapy to endocrine therapy, and RxPONDER extended that finding to postmenopausal women with 1 to 3 positive nodes. Younger women with mid-range scores did show some chemotherapy benefit in TAILORx, which may reflect ovarian suppression rather than cytotoxic effect, and this remains debated. Exact Sciences markets it; MammaPrint (Agendia) and Prosigna/PAM50 are alternatives. For a newcomer: a tumour test that lets most women with early hormone-positive breast cancer safely skip chemotherapy.

## Fields

- Kind: Treatment
- Status: established
- Last checked: 2026-09-04
- Modality: Gene-expression prognostic/predictive assay
- Mechanism: RT-PCR of 16 cancer and 5 reference genes into a recurrence score.

## Sources

- TAILORx (NEJM 2018): https://doi.org/10.1056/NEJMoa1804710
- NICE DG34: tumour profiling tests for breast cancer: https://www.nice.org.uk/guidance/dg34

## Connected records

- drugs: [Breast Cancer Index](https://onco.cc/drugs/breast-cancer-index/), [EndoPredict](https://onco.cc/drugs/endopredict/), [MammaPrint (70-gene signature)](https://onco.cc/drugs/mammaprint/), [Prosigna (PAM50)](https://onco.cc/drugs/prosigna/)
- pairings: [Gene-expression assay → chemotherapy omission](https://onco.cc/pairings/genomic-assay-to-chemo-omission/)
- cancers: [Ductal carcinoma in situ (DCIS)](https://onco.cc/cancers/ductal-carcinoma-in-situ/), [High-risk early HR-positive breast cancer](https://onco.cc/cancers/hr-positive-early-high-risk/), [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/), [Invasive breast carcinoma of no special type (invasive ductal carcinoma)](https://onco.cc/cancers/invasive-breast-carcinoma-no-special-type/)
- technologies: [Companion diagnostics](https://onco.cc/technologies/companion-diagnostic/), [Gene-expression prognostic assays](https://onco.cc/technologies/gene-expression-prognostic-assays/), [RNA sequencing & expression profiling](https://onco.cc/technologies/rna-seq/)
- companies: [Exact Sciences (Abbott)](https://onco.cc/companies/exact-sciences/), [NSABP Foundation](https://onco.cc/companies/nsabp-foundation/)
- trials: [RxPONDER (SWOG S1007)](https://onco.cc/trials/rxponder/), [TAILORx](https://onco.cc/trials/tailorx/)
- people: [Joseph A. Sparano](https://onco.cc/people/joseph-sparano/), [Kathy S. Albain](https://onco.cc/people/kathy-albain/), [Kevin Kalinsky](https://onco.cc/people/kevin-kalinsky/)
- ideas: [A formal regulatory route for validating a biomarker on archived trial samples](https://onco.cc/ideas/idea-tr2-prospective-retrospective-path/), [A fund for prospective validation of academic biomarkers and companion diagnostics](https://onco.cc/ideas/idea-fund-biomarker-validation-fund/), [Payer-funded trials that omit surgery or radiotherapy in low-risk patients](https://onco.cc/ideas/idea-fund-omission-deescalation-trials/)
- terms: [Enrichment and biomarker-stratified designs](https://onco.cc/terms/biomarker-stratified-design/)
- institutions: [Montefiore Einstein Comprehensive Cancer Center](https://onco.cc/institutions/montefiore-einstein/), [Winship Cancer Institute of Emory University](https://onco.cc/institutions/emory-winship/)
- roadmaps: [Diagnostics roadmap: stains → gene panels → blood tests that decide treatment](https://onco.cc/roadmaps/diagnostics-roadmap/)

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