Inter-observer Variability in the Segmentation of Prostate Tumour Lesions Using Multiparametric MRI (VARIOP)

Study Overview
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Brief Summary
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Following the major technological and scientific advances in external radiotherapy in recent decades, thanks to the use of three-dimensional conformal techniques combined with intensity modulation, image-guided radiotherapy has enabled radiotherapists to increase doses without increasing sequelae and complications, giving rise to the term dose escalation. Following multiple dose-escalation clinical trials showing better biological control of PSA, the results of the latest phase 3 FLAME trial incorporated the notion of intraprostatic boost in relation to the primary prostate lesion, considered to be the preferred site of neoplastic recurrence in prostate cancer. This leads to the first question, which concerns the identification of the dominant lesion and its precise delimitation. This last point is subject to variation between operators. A retrospective cohort from the Finistère region will therefore be used to develop a number of study points relating to : inter-operator contour variability Factors influencing contour Impact of contour variability on dosimetry Automatic segmentation

Detailed Description
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Following the major technological and scientific advances in external radiotherapy in recent decades, thanks to the use of three-dimensional conformal techniques combined with intensity modulation, image-guided radiotherapy has enabled radiotherapists to increase doses without increasing sequelae and complications, giving rise to the term dose escalation. Following multiple dose-escalation clinical trials showing better biological control of PSA, the results of the latest phase 3 FLAME trial incorporated the notion of intraprostatic boost in relation to the primary prostate lesion, considered to be the preferred site of neoplastic recurrence in prostate cancer. One of the issues raised by such a study is the methodology used to contour the tumour lesion, an issue which concerns the whole field of radiotherapy. The reference imaging technique for diagnosing prostate cancer, and more specifically the dominant tumour lesion, is multiparametric Magnetic Resonance Imaging. This leads to the first question, which concerns the identification of the dominant lesion and its precise delimitation. This last point is subject to variation between operators. A retrospective cohort from the Finistère region will therefore be used to develop a number of study points relating to : inter-operator contour variability Factors influencing contour Impact of contour variability on dosimetry Automatic segmentation

Official Title
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Inter-observer Variability in the Segmentation of Prostate Tumour Lesions Using Multiparametric MRI

Conditions
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Prostate Cancer

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥ 18 years Histologically proven localized prostatic neoplasia on trans-rectal biopsies. Multiparametric prostate MRI performed prior to prostate biopsies. No opposition expressed Patient affiliated to a social security scheme Exclusion Criteria: History of surgery, prostatic irradiation or hormonal treatment prior to diagnosis. History of prostate cancer No identifiable target lesion on mpMRI (<PIRADS 3) Opposition formulated Patient under legal protection (guardianship, curatorship, etc.)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Inter-observer variability | The main criterion for judging inter-observer variability is the spatial overlap of contours on mpMRI, represented by the DICE similarity coefficient, which ranges from 0 to 1, where 1 represents zero variability between contours of the same lesion. | through study completion, an average of 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Clinical factors influencing inter-observer variability. | Subgroup analysis of radio-clinical-histological factors likely to influence inter-observer variability. | through study completion, an average of 6 months | 
| Assessing inter-sequence reproducibility | Assessing inter-sequence reproducibility | through study completion, an average of 6 months | 
| Dosimetric impact of Inter-observer variability | The influence of variability on dosimetry in IMRT/VMAT conformal radiotherapy. | through study completion, an average of 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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radiotherapy, MRI, segmentation