# Major pathological response (MPR)

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

## TL;DR

When, after pre-surgery treatment, the removed tumour contains little or no living cancer: 10% or less viable cells.

## Summary

Defined by the International Neoadjuvant Melanoma Consortium as ≤10% viable tumour (pathological complete response is 0%). In NADINA and earlier OpCACI trials, MPR predicted very low relapse risk and was used to decide whether adjuvant therapy could be omitted. The melanoma analogue of pCR in breast cancer.

## Fields

- Kind: Term
- Last checked: 2026-09-07
- Also known as: major pathologic response; ≤10% viable tumour

## Sources

- INMC pathological assessment after neoadjuvant therapy for melanoma (Tetzlaff et al., Ann Oncol 2018): https://doi.org/10.1093/annonc/mdy226

## Connected records

- cancers: [Lung cancer (all types)](https://onco.cc/cancers/lung-cancer/), [Melanoma](https://onco.cc/cancers/melanoma/), [Resectable stage I to III non-small-cell lung cancer](https://onco.cc/cancers/resectable-nsclc/), [Stage III melanoma (after surgery)](https://onco.cc/cancers/stage-iii-melanoma/)
- terms: [Interferon-gamma gene signature (T-cell-inflamed signature)](https://onco.cc/terms/interferon-gamma-signature/), [Neoadjuvant / adjuvant / perioperative](https://onco.cc/terms/neoadjuvant-adjuvant/), [Pathologic complete response (pCR)](https://onco.cc/terms/pcr/)
- trials: [NADINA](https://onco.cc/trials/nadina/), [Neotorch](https://onco.cc/trials/neotorch/)
- key papers: [Pathological assessment of resection specimens after neoadjuvant therapy for metastatic melanoma](https://onco.cc/key-papers/paper-tetzlaff-ann-oncol/)
- pairings: [Neoadjuvant immunotherapy → response-adapted adjuvant](https://onco.cc/pairings/neoadjuvant-io-response-adapted/)
- ideas: [Pre-surgery platform trials that test combinations on pathological response in months](https://onco.cc/ideas/idea-tr2-neoadjuvant-combo-platform/), [Treat the draining lymph node before removing it](https://onco.cc/ideas/idea-bio2-lymph-node-immune-priming/), [Use pre-surgery immunotherapy windows as the field's biomarker engine](https://onco.cc/ideas/idea-bio2-neoadjuvant-biomarker-engine/)

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