# PARTIQoL

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

## TL;DR

The first multicentre randomised trial of protons versus IMRT for localised prostate cancer found no difference in bowel, urinary or sexual quality of life and the same cancer control at five years.

## Summary

PARTIQoL (NCT01617161) randomised 450 men with low- or intermediate-risk localised prostate cancer at 29 centres between 2012 and 2021 to proton beam therapy or intensity-modulated photon radiotherapy, without hormone therapy, with the change in EPIC bowel quality of life at 24 months as the primary endpoint. It is one of the few adult proton-versus-photon trials able to test whether a distal LET and RBE difference near rectum and bladder is clinically real, and accrual was slow in a field where patients can obtain protons off-trial.

Reported as a late-breaking abstract at ASTRO 2024 with a median follow-up of 60.3 months: bowel scores fell only slightly in both arms (91.8 with protons and 91.9 with IMRT at 24 months, from 93.7 and 93.5 at baseline; p=0.836), with no differences in urinary incontinence, urinary irritation or sexual function at any time point and five-year progression-free survival of 93.4% with protons and 93.7% with IMRT (p=0.706). Neither technique beat the other, so the adult proton case in prostate cancer rests on other arguments than a wider therapeutic window.

## Fields

- Kind: Trial
- Status: completed
- Last checked: 2026-09-17
- Tags: radiation-wave5
- Registry id: NCT01617161
- Phase: 3
- Setting: Low- and intermediate-risk localised prostate cancer: proton beam therapy versus intensity-modulated photon radiotherapy
- Sponsor: Massachusetts General Hospital
- Enrolled: 450
- Result: No difference between protons and IMRT in EPIC bowel quality of life at 24 months (primary endpoint, p=0.836) or in urinary or sexual function; five-year progression-free survival 93.4% vs 93.7%.
- Outcomes: EPIC bowel quality of life at 24 months: Proton beam therapy 91.8 score (0-100) vs IMRT 91.9 score (0-100); Progression-free survival at 5 years: Proton beam therapy 93.4% vs IMRT 93.7%

## Notes

- PARTIQoL randomised men with low-risk or intermediate-risk prostate cancer to proton beam therapy or photon-based intensity-modulated radiotherapy, stratified by institution, age, use of a rectal spacer and fractionation schedule (conventional 79.2 Gy in 44 fractions against moderately hypofractionated 70.0 Gy in 28 fractions). The primary endpoint is change from baseline in bowel health on the Expanded Prostate Index Composite at 24 months. Median age of the 437 analysed men was 68 (range 46 to 89); 41 percent had low-risk and 59 percent intermediate-risk disease; 49 percent had conventional and 51 percent moderately hypofractionated treatment; 48 percent used a rectal spacer; and among those having protons, 48 percent received pencil-beam scanning. The arms were balanced at baseline (International Journal of Radiation Oncology Biology Physics 2025).
- The trial took nine years to accrue 450 men, and its authors published the feasibility experience deliberately, because payer engagement, multicentre collaboration and protocol updates to keep pace with technique were what made a randomised proton comparison possible at all. That is the transferable finding; the primary bowel-health result is reported separately.

## Sources

- ClinicalTrials.gov NCT01617161: https://clinicaltrials.gov/study/NCT01617161
- ASTRO 2024 late-breaking abstract (IJROBP): https://doi.org/10.1016/j.ijrobp.2024.08.012
- PARTIQoL feasibility and baseline characteristics (International Journal of Radiation Oncology Biology Physics 2025): https://doi.org/10.1016/j.ijrobp.2024.09.043

## Connected records

- cancers: [Prostate cancer](https://onco.cc/cancers/prostate/)
- technologies: [IMRT / IGRT (modern external beam)](https://onco.cc/technologies/imrt-igrt/), [Proton therapy](https://onco.cc/technologies/proton-therapy/)
- institutions: [Massachusetts General Hospital Cancer Center](https://onco.cc/institutions/mgh/)
- terms: [Alpha/beta ratio](https://onco.cc/terms/alpha-beta-ratio/), [Bragg peak](https://onco.cc/terms/bragg-peak/), [How many radiotherapy visits: the prostate fractionation trials](https://onco.cc/terms/prostate-radiotherapy-fractionation/), [Linear energy transfer (LET)](https://onco.cc/terms/linear-energy-transfer/), [Relative biological effectiveness (RBE)](https://onco.cc/terms/relative-biological-effectiveness/)
- trials: [CHHiP](https://onco.cc/trials/chhip/), [PACE-B](https://onco.cc/trials/pace-b/)
- key papers: [PARTIQoL: phase 3 randomised trial of proton therapy versus IMRT for localised prostate cancer (ASTRO 2024 late-breaking abstract)](https://onco.cc/key-papers/paper-partiqol-astro-2024/)
- pairings: [Caution: proton therapy vs IMRT](https://onco.cc/pairings/proton-vs-imrt/)
- ideas: [Pooled coverage-with-evidence for proton therapy across all centres](https://onco.cc/ideas/idea-fund-proton-coverage-with-evidence/), [Use LET, RBE and alpha/beta to decide when protons beat IMRT](https://onco.cc/ideas/idea-bio2-let-rbe-ab-selects-protons/)

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