# Endocrine therapy and endocrine resistance

Source: https://onco.cc/terms/endocrine-therapy-resistance/  
OnCo record `endocrine-therapy-resistance` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Endocrine therapy blocks the hormones that feed some breast and prostate cancers; endocrine resistance is when the cancer learns to grow without them.

## Summary

Hormonal therapy in oncology manipulates the endocrine system with drugs that block hormone production or hormone receptors and is one of the main modalities of medical oncology alongside chemotherapy and targeted therapy (Wikipedia). In oestrogen receptor-positive breast cancer, resistance arises through ESR1 ligand-binding-domain mutations, loss of receptor expression and growth-factor pathway activation, which is why oral SERDs and CDK4/6 inhibitors are combined with or follow aromatase inhibitors.

## Fields

- Kind: Term
- Last checked: 2026-09-24
- Also known as: endocrine resistance; endocrine-resistant; hormone therapy resistance; anti-oestrogen resistance; ESR1 mutation resistance
- Tags: cansim-terms

## Notes

- Listed in the CanSim terms map 1.0.0 (docs/onco/terms.json, generated 2026-09-24), CC BY 4.0, attribution: CanSim project, an open, public-data-first cancer foundation-model programme; CanSim page path /terms/endocrine-therapy-resistance.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Hormonal_therapy_(oncology)
- Wikipedia: https://en.wikipedia.org/wiki/Hormonal_therapy_(oncology)

## Connected records

- terms: [Aromatase inhibitor](https://onco.cc/terms/aromatase-inhibitor/), [Cancer AI vocabulary (CanSim terms map)](https://onco.cc/terms/cancer-ai-vocabulary/), [Hormone receptor status (ER / PR)](https://onco.cc/terms/hormone-receptor-status/), [Hormone therapy](https://onco.cc/terms/hormone-therapy/)
- targets: [Estrogen receptor (ERα)](https://onco.cc/targets/estrogen-receptor/)

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JSON: https://onco.cc/api/v1/entities/endocrine-therapy-resistance.json