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MRI target delineation may reduce long-term toxicity after prostate radiotherapy
Lotte Sander1, Niels Christian Langkilde, Mats Holmberg
1Department of Urology, Aalborg University Hospital , Aalborg , Denmark.
Background And Purpose:
Aiming for minimal toxicity after radical prostate cancer (PC) radiotherapy (RT), magnetic resonance imaging (MRI) target delineation could be a possible benefit knowing that clinical target volumes (CTV) are up to 30% smaller, when CTV delineation on MRI is compared to standard computed tomography (CT). This study compares long-term toxicity using CT or MRI delineation before PC RT.
Material And Methods:
Urinary and rectal toxicity assessments 36 months after image-guided RT (78 Gy) using CTC-AE scores in two groups of PC patients. Peak symptom score values were registered. One group of patients (n=72) had standard CT target delineation and gold markers as fiducials. Another group of patients (n=73) had MRI target delineation and a nickel-titanium stent as fiducial.
Results:
At 36 months no difference in overall survival (92% in both groups, p=0.29) or in PSA-relapse free survival was found between the groups (MRI=89% and CT=94%, p=0.67). A significantly smaller CTV was found in the MRI group (p=0.02). Urinary retention and frequency were significantly reduced in the MRI group (p=0.03 in the matter of both). The overall urinary and rectal toxicity did not differ between the two groups.
Conclusion:
MRI delineation leads to a significantly reduced CTV. Significantly lower urinary frequency and urinary retention toxicity scores were observed following MRI delineation. The study did not find significant differences in overall urinary or rectal toxicity between the two groups. PSA-relapse survival did not differ between the two groups at 36 months.
Insights
Magnetic resonance imaging (MRI) for prostate cancer radiotherapy reduced clinical target volumes, leading to significantly lower urinary retention and frequency. However, overall toxicity and survival rates did not differ between MRI and computed tomography (CT) delineation groups.
Area of Science:
- Radiation Oncology
- Medical Imaging
- Urology
Background:
- Radical prostate cancer (PC) radiotherapy (RT) aims for minimal toxicity.
- Clinical target volumes (CTV) for PC RT can be up to 30% smaller using MRI compared to CT.
- Comparing long-term toxicity between CT and MRI delineation is crucial.
Purpose of the Study:
- To compare long-term urinary and rectal toxicity in prostate cancer patients undergoing radiotherapy.
- To evaluate the impact of MRI versus CT-based target delineation on toxicity outcomes.
- To assess differences in survival rates based on delineation method.
Main Methods:
- Two groups of PC patients (n=72 CT, n=73 MRI) received image-guided RT (78 Gy).
- Urinary and rectal toxicity were assessed using CTC-AE scores at 36 months post-RT.
- CT group used gold markers; MRI group used a nickel-titanium stent for fiducials.
Main Results:
- No significant difference in overall survival or PSA-relapse free survival at 36 months.
- MRI delineation resulted in a significantly smaller CTV (p=0.02).
- The MRI group showed significantly reduced urinary retention and frequency (p=0.03).
Conclusions:
- MRI delineation significantly reduces CTV in prostate cancer radiotherapy.
- MRI-based delineation is associated with significantly lower urinary retention and frequency.
- No significant differences were observed in overall urinary/rectal toxicity or PSA-relapse survival between CT and MRI groups at 36 months.
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