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Radiation Oncology

, 10:243

Clinical Radiation Oncology

Abstract

BackgroundA prospective clinical trial was conducted to evaluate the feasibility of a novel approach to the treatment of patients with high risk prostate cancer HRPC through the use of a nomogram to tailor radiotherapy target volumes.

MethodsTwenty seven subjects with HRPC were treated with a mildly hypofractionated radiotherapy regimen using image-guided IMRT technique between Jun-2013-Jan-2015.

A set of validated prognostic factors were inputted into the Memorial-Sloan-Kettering Cancer Center MSKCC prostate cancer nomogram to estimate risk of loco-regional spread LRS. The nomogram risk estimates for extra-capsular extension ECE, seminal vesicles involvement SVI, and pelvic lymph nodes involvement LNI were used to adapt radiotherapy treatment volumes based on a risk threshold of ≥15 % in all cases. A planning guide was used to delineate target volumes and organs at risk OAR. Up to three dose levels were administered over 28 fractions; 70Gy for gross disease in the prostate +-− seminal vesicles 2.5Gy-fraction, 61.6Gy for subclinical peri-prostatic disease 2.2Gy-fraction and 50.4Gy to pelvic nodes 1.8Gy-fraction.

Data regarding protocol adherence, nomogram use, radiotherapy dose distribution, and acute toxicity were collected.

ResultsNomogram use

100 % of patients were treated for ECE, 88.9 % for SVI, and 70.4 % for LNI. The three areas at risk of LRS were appropriately treated according to the study protocol in 98.8 % cases. The MSKCC nomogram estimates for LRS differed significantly between the time of recruitment and analysis.

Contouring protocol compliance

Compliance with the trial contouring protocol for up to seven target volumes was 93.0 % 159-171. Compliance with protocol for small bowel contouring was poor 59.3 %.

Dose constraints compliance

Compliance with dose constraints for target volumes was 97.4 % 191-196. Compliance with dose constraints for OAR was 88.2 % 285-323.

Acute toxicity

There were no grade 3 acute toxicities observed. 20-27 74.1 % and 6-27 22.2 % patients experienced a grade 2 genitourinary and gastrointestinal toxicity respectively.

ConclusionsWe have demonstrated the feasibility of this novel risk-adapted radiation treatment protocol for HRPC. This study has identified key learning points regarding this approach, including the importance of standardization and updating of risk quantification tools, and the utility of an observer to verify their correct use.

Trial registrationClincialTrials.gov identifier NCT01418040.

Hunter New England Human Research Ethics Committee HNEHREC reference number 12-08-15-4.02

KeywordsProstatic neoplasms Radiotherapy Nomograms AbbreviationsADTandrogen deprivation therapy

bNEDbiochemical no evidence of disease

CTcomputed tomography

CTVclinical target volume

ECEextra-capsular extension

ECOGEastern Cooperative Oncology Group

GIgastrointestinal

GSGleason Score

GUgenitourinary

HNSCCmucosal squamous cell carcinoma of the head and neck

HRPChigh risk prostate cancer

IMRTintensity modulated radiotherapy

LNIpelvic lymph nodes involvement

LRSloco-regional spread

MRImagnetic resonance imaging

MSKCCMemorial-Sloan-Kettering Cancer Center

OARorgans at risk

PETpositron emission tomography

PLNpelvic lymph nodes

PRVplanning organ at risk volume

PSAprostate specific antigen

PSMAprostate specific membrane antigen

PTVplanning target volume

RCTrandomized controlled trials

RTradiotherapy

RTOGRadiation Therapy Oncology Group

SVseminal vesicles

SVIseminal vesicles involvement

WPRTwhole pelvis radiotherapy

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Autor: Raymond Wu - Hannah Woodford - Anne Capp - Perry Hunter - Gary Cowin - Keen-Hun Tai - Paul L. Nguyen - Peter Chong - Jara

Fuente: https://link.springer.com/







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