# Precision roadmap: margins measured in millimetres → tests that find a target → doses fitted to the person → precision that changes outcomes

Source: https://onco.cc/roadmaps/precision-roadmap/  
OnCo record `precision-roadmap` (Roadmap). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Cancer care is limited by how precise it is: how small a tumour a test can find, how close to it a surgeon can cut, how tightly a beam can be aimed and how well a dose fits the person. This roadmap follows each of those from where it stands now to the next step, and says plainly where more precision has been shown to help a patient and where it has not.

## Summary

Precision means something different in each part of cancer care, and it is measured in different units. In radiotherapy it is millimetres: the margin of healthy tissue added around a target because the tumour moves and the set-up varies. In surgery it is whether the edge of what was removed is clear, and how often a second operation is needed. In imaging it is the smallest deposit a scan can see. In molecular testing it is how little tumour DNA a test can find, and separately how often the result points to a drug that works. In dosing it is how far a dose chosen by body size, or by the highest dose people tolerated in a first trial, sits from the dose a particular person needs.

The record so far is uneven, and that is the point of setting the domains side by side. Tighter radiotherapy margins have randomised evidence of fewer side effects: in MIRAGE, cutting the prostate margin from 4 mm to 2 mm with MRI guidance lowered acute moderate urinary side effects from 43.4 to 24.4 per cent. Genotype-guided dosing of fluoropyrimidines has prospective evidence of fewer severe side effects in carriers of DPYD variants. Molecular matching, the form of precision most often promised, finds a target in a minority and helps fewer: NCI-MATCH found an actionable alteration in 37.6 per cent of 5,954 people and assigned 17.8 per cent to a matched treatment, and a 2018 estimate put the share of US patients with metastatic cancer who benefit from genome-targeted therapy at 4.90 per cent.

The steps below run from the measurements that made precision a number to the ones that would make it routine. The precision matrix at /live/precision/ holds one row per technology: what precision means there, how precise it is today with the source's own words, what limits it, the next step and what that step would buy a patient. Where a technology is sold as more precise than its evidence shows, the row carries a grade on the same scale OnCo uses for complementary therapies.

## Fields

- Kind: Roadmap
- Last checked: 2026-10-20
- Also known as: Precision in cancer care; How precise cancer treatment is; Precision oncology roadmap; Precision matrix
- Tags: precision

## Sources

- OnCo: the precision matrix, technology by technology: https://onco.cc/live/precision/
- van Herk et al.: the probability of correct target dosage, dose-population histograms for deriving treatment margins in radiotherapy (International Journal of Radiation Oncology, Biology, Physics 2000): https://doi.org/10.1016/S0360-3016(00)00518-6
- Darby et al.: risk of ischemic heart disease in women after radiotherapy for breast cancer (New England Journal of Medicine 2013): https://doi.org/10.1056/NEJMoa1209825
- Kishan et al.: MRI-guided versus CT-guided stereotactic body radiotherapy for prostate cancer, the MIRAGE randomised trial (JAMA Oncology 2023): https://doi.org/10.1001/jamaoncol.2022.6558
- Chagpar et al.: a randomised, controlled trial of cavity shave margins in breast cancer (New England Journal of Medicine 2015): https://doi.org/10.1056/NEJMoa1504473
- Hofman et al.: PSMA PET-CT before curative-intent surgery or radiotherapy, the proPSMA randomised study (Lancet 2020): https://doi.org/10.1016/S0140-6736(20)30314-7
- Smith et al.: intraoperative fluorescence guidance for breast cancer lumpectomy surgery, the INSITE trial (NEJM Evidence 2023): https://doi.org/10.1056/EVIDoa2200333
- Flaherty et al.: molecular landscape and actionable alterations in NCI-MATCH (Journal of Clinical Oncology 2020): https://doi.org/10.1200/JCO.19.03010
- Marquart, Chen and Prasad: estimation of the percentage of US patients with cancer who benefit from genome-driven oncology (JAMA Oncology 2018): https://doi.org/10.1001/jamaoncol.2018.1660
- Henricks et al.: DPYD genotype-guided dose individualisation of fluoropyrimidine therapy, a prospective safety analysis (Lancet Oncology 2018): https://doi.org/10.1016/S1470-2045(18)30686-7
- FDA Oncology Center of Excellence: Project Optimus: https://www.fda.gov/about-fda/oncology-center-excellence/project-optimus
- Tie et al.: circulating tumour DNA analysis guiding adjuvant therapy in stage II colon cancer, the DYNAMIC trial (New England Journal of Medicine 2022): https://doi.org/10.1056/NEJMoa2200075

## Connected records

- roadmaps: [ctDNA tests roadmap: from a curiosity in plasma to blood tests that decide treatment](https://onco.cc/roadmaps/ctdna-tests/), [Diagnostics roadmap: stains → gene panels → blood tests that decide treatment](https://onco.cc/roadmaps/diagnostics-roadmap/), [Molecular imaging roadmap: FDG → PSMA → FAP → antigen and immune PET](https://onco.cc/roadmaps/molecular-imaging-roadmap/), [Radiotherapy roadmap: X-rays → shaped beams → fewer fractions, particles and FLASH](https://onco.cc/roadmaps/radiation-roadmap/), [Surgery roadmap: radical operations → less surgery → no surgery when a drug has done the work](https://onco.cc/roadmaps/surgery-roadmap/)
- ideas: [Apply Project Optimus to drugs already on the market](https://onco.cc/ideas/idea-cost-optimus-legacy-drugs/), [Dose chemotherapy by muscle mass, not body surface area](https://onco.cc/ideas/idea-bio2-lean-mass-dosing/), [Dosimetry-personalised PRRT instead of four fixed cycles](https://onco.cc/ideas/idea-net-dosimetry-prrt/), [Randomised lower-dose trials for approved drugs with quality of life as the primary endpoint](https://onco.cc/ideas/idea-moon-post-approval-dose-deescalation/), [Real-time margin assessment and image-guided surgery as the global standard](https://onco.cc/ideas/idea-moon-image-guided-surgery-everywhere/), [Retire the 3+3: model-based dose finding that counts late and chronic side effects](https://onco.cc/ideas/idea-tr1-model-based-dose-finding-with-late-toxicity/), [Test drugs on the patient's own cancer cells when there is no trial to join](https://onco.cc/ideas/idea-bio2-functional-precision-rare/)
- fronts: [Chemotherapy](https://onco.cc/fronts/chemotherapy/), [Diagnostics & Biomarkers](https://onco.cc/fronts/diagnostics/), [Imaging](https://onco.cc/fronts/imaging/), [Radiation Therapy](https://onco.cc/fronts/radiation/), [Surgery & Interventional](https://onco.cc/fronts/surgery/), [Targeted Therapy](https://onco.cc/fronts/targeted-therapy/)
- technologies: [Adaptive radiotherapy (online replanning)](https://onco.cc/technologies/adaptive-radiotherapy/), [Cancer variant knowledgebases and molecular tumour boards](https://onco.cc/technologies/variant-knowledgebases/), [Cardio-oncology](https://onco.cc/technologies/cardio-oncology/), [Companion diagnostics](https://onco.cc/technologies/companion-diagnostic/), [Digital pathology & AI](https://onco.cc/technologies/digital-pathology-ai/), [DPYD genotyping and DPD phenotyping before fluoropyrimidines](https://onco.cc/technologies/dpyd-genotyping/), [Ex vivo drug sensitivity screening in blood cancers (EXALT)](https://onco.cc/technologies/functional-precision-medicine-haematology/), [Fluorescence-guided surgery](https://onco.cc/technologies/fluorescence-guided-surgery/), [IMRT / IGRT (modern external beam)](https://onco.cc/technologies/imrt-igrt/), [Intraoperative fluorescence and Cerenkov imaging systems (SPY, Firefly, LumiSystem, LightPath)](https://onco.cc/technologies/intraoperative-fluorescence-imaging-systems/), [Liquid biopsy (ctDNA)](https://onco.cc/technologies/liquid-biopsy/), [MR-guided adaptive radiotherapy](https://onco.cc/technologies/mr-linac/), [MRD / molecular residual disease testing](https://onco.cc/technologies/mrd-testing/), [Pharmacogenomic testing before chemotherapy](https://onco.cc/technologies/oncology-pharmacogenomics/), [Proton therapy](https://onco.cc/technologies/proton-therapy/), [PSMA PET](https://onco.cc/technologies/psma-pet/), [Respiratory motion management (4D-CT, gating, breath-hold, tracking)](https://onco.cc/technologies/respiratory-motion-management/), [SBRT / SABR (stereotactic radiotherapy)](https://onco.cc/technologies/sbrt/), [Sentinel lymph node biopsy](https://onco.cc/technologies/sentinel-node/), [The linear-quadratic model and fractionation](https://onco.cc/technologies/linear-quadratic-model/)
- drugs: [Capecitabine](https://onco.cc/drugs/capecitabine/), [Fluorouracil (5-FU)](https://onco.cc/drugs/fluorouracil/), [Pegulicianine](https://onco.cc/drugs/pegulicianine/), [Signatera](https://onco.cc/drugs/signatera/), [Sotorasib](https://onco.cc/drugs/sotorasib/)
- terms: [Circulating tumour DNA (ctDNA)](https://onco.cc/terms/ctdna/), [Deep inspiration breath-hold (DIBH)](https://onco.cc/terms/deep-inspiration-breath-hold/), [Hypofractionation (fewer, larger radiotherapy doses)](https://onco.cc/terms/hypofractionation/), [Margins after breast-conserving surgery, and second operations](https://onco.cc/terms/breast-margins-and-re-excision/), [Minimal / molecular residual disease (MRD)](https://onco.cc/terms/mrd/), [Next-generation sequencing (NGS)](https://onco.cc/terms/ngs/), [Project Optimus](https://onco.cc/terms/project-optimus/), [Resection margins (R0 / R1 / R2)](https://onco.cc/terms/resection-margins/), [Tumour-agnostic (tissue-agnostic) approval](https://onco.cc/terms/tumour-agnostic/)
- trials: [DYNAMIC](https://onco.cc/trials/dynamic/), [IMvigor011](https://onco.cc/trials/imvigor011/), [NCI-MATCH (EAY131)](https://onco.cc/trials/nci-match/), [proPSMA](https://onco.cc/trials/propsma/)
- bottlenecks: [Wrong doses](https://onco.cc/bottlenecks/b-dose-optimisation/)
- key papers: [DPYD genotype-guided dose individualisation of fluoropyrimidine therapy in patients with cancer: a prospective safety analysis](https://onco.cc/key-papers/paper-henricks-lancet-oncol/), [Magnetic Resonance Imaging-Guided vs Computed Tomography-Guided Stereotactic Body Radiotherapy for Prostate Cancer: The MIRAGE Randomized Clinical Trial](https://onco.cc/key-papers/paper-kishan-jama-oncol/), [Molecular Landscape and Actionable Alterations in a Genomically Guided Cancer Clinical Trial: National Cancer Institute Molecular Analysis for Therapy Choice (NCI-MATCH)](https://onco.cc/key-papers/paper-flaherty-j-clin-oncol/), [proPSMA: PSMA PET-CT versus conventional imaging for staging high-risk prostate cancer](https://onco.cc/key-papers/paper-propsma-hofman-lancet-2020/)

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