MRI scans significantly change target coverage decisions in radical radiotherapy for prostate cancer

Abstract Background The aim of this study was to evaluate and compare the performance of intensity modulated radiation therapy (IMRT) plans, planned for low-field strength magnetic resonance (MR) guided linear accelerator (linac) delivery (labelled IMRT MRL plans), and clinical conventional volumetric modulated arc therapy (VMAT) plans, for the treatment of prostate cancer (PCa). Both plans used the original planning target volume (PTV) margins. Additionally, the potential dosimetric benefits of MR-guidance were estimated, by creating IMRT MRL plans using smaller PTV margins. Materials and methods 20 PCa patients previously treated with conventional VMAT were considered. For each patient, two different IMRT MRL plans using the low-field MR-linac treatment planning system were created: one with original (orig.) PTV margins and the other with reduced (red.) PTV margins. Dose indices related to target coverage, as well as dose-volume histogram (DVH) parameters for the target and organs at risk (OAR) were compared. Additionally, the estimated treatment delivery times and the number of monitor units (MU) of each plan were evaluated. Results The dose distribution in the high dose region and the target volume DVH parameters (D98%, D50%, D2% and V95%) were similar for all three types of treatment plans, with deviations below 1% in most cases. Both IMRT MRL plans (orig. and red. PTV margins) showed similar homogeneity indices (HI), however worse values for the conformity index (CI) were also found when compared to VMAT. The IMRT MRL plans showed similar OAR sparing when the orig. PTV margins were used but a significantly better sparing was feasible when red. PTV margins were applied. Higher number of MU and longer predicted treatment delivery times were seen for both IMRT MRL plans. Conclusions A comparable plan quality between VMAT and IMRT MRL plans was achieved, when applying the same PTV margin. However, online MR-guided adaptive radiotherapy allows for a reduction of PTV margins. With a red. PTV margin, better sparing of the surrounding tissues can be achieved, while maintaining adequate target coverage. Nonetheless, longer treatment delivery times, characteristic for the IMRT technique, have to be expected.

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Should we affraid of induced cancer in group of patients after radical radiotherapy of prostate cancer?

Reports of Practical Oncology & Radiotherapy ◽

10.1016/s1507-1367(10)60034-x ◽

2009 ◽

Vol 14 (5) ◽

pp. 184-190 ◽

Cited By ~ 1

Author(s):

Piotr MILECKI ◽

Anna ADAMSKA ◽

Andrzej ROSZAK ◽

Dominika KALETA

Keyword(s):

Prostate Cancer ◽

Radical Radiotherapy

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Quality of Life after Radical Radiotherapy for Prostate Cancer: Longitudinal Study from a Randomised Trial of External Beam Radiotherapy Alone or in Combination with High Dose Rate Brachytherapy

Clinical Oncology ◽

10.1016/j.clon.2013.01.001 ◽

2013 ◽

Vol 25 (5) ◽

pp. 321-327 ◽

Cited By ~ 30

Author(s):

P.J. Hoskin ◽

A.M. Rojas ◽

P.J. Ostler ◽

R. Hughes ◽

G.J. Lowe ◽

...

Keyword(s):

Quality Of Life ◽

Prostate Cancer ◽

External Beam Radiotherapy ◽

Randomised Trial ◽

High Dose Rate ◽

High Dose ◽

External Beam ◽

Radical Radiotherapy ◽

Radiotherapy Alone

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Radical Radiotherapy for Prostate Cancer

Urological Cancers in Clinical Practice ◽

10.1007/978-1-84628-507-3_1 ◽

2007 ◽

pp. 1-23

Author(s):

Mererid Evans ◽

Malcolm D. Mason

Keyword(s):

Prostate Cancer ◽

Radical Radiotherapy

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The introduction of dedicated planning MR-CT fusion for radical radiotherapy of prostate cancer

Physica Medica ◽

10.1016/j.ejmp.2018.06.032 ◽

2018 ◽

Vol 52 ◽

pp. 170

Author(s):

Ciara Lyons ◽

Lynn Graham ◽

Bernadette McCafferty ◽

Darren Brady ◽

Patrizia Porcu ◽

...

Keyword(s):

Prostate Cancer ◽

Radical Radiotherapy

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EP-1640 Radical radiotherapy in elderly prostate cancer patients: a monoinstitutional experience

Radiotherapy and Oncology ◽

10.1016/s0167-8140(19)32060-2 ◽

2019 ◽

Vol 133 ◽

pp. S883-S884

Author(s):

C.L. Deantoni ◽

A. Fodor ◽

C. Fiorino ◽

C. Cozzarini ◽

F. Zerbetto ◽

...

Keyword(s):

Prostate Cancer ◽

Cancer Patients ◽

Radical Radiotherapy

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Acute and subacute prostate MRI findings after MRI-guided transurethral ultrasound ablation of prostate cancer

Acta Radiologica ◽

10.1177/0284185120976931 ◽

2020 ◽

pp. 028418512097693

Author(s):

Pietari Mäkelä ◽

Mikael Anttinen ◽

Visa Suomi ◽

Aida Steiner ◽

Jani Saunavaara ◽

...

Keyword(s):

Prostate Cancer ◽

Diagnostic Value ◽

Optimal Timing ◽

Mri Findings ◽

Apparent Diffusion Coefficient Values ◽

Mri Scans ◽

Ultrasound Ablation ◽

Mri Guided ◽

Transurethral Ultrasound

Background Magnetic resonance imaging (MRI)-guided transurethral ultrasound ablation (TULSA) is an emerging method for treatment of localized prostate cancer (PCa). TULSA-related subacute MRI findings have not been previously characterized. Purpose To evaluate acute and subacute MRI findings after TULSA treatment in a treat-and-resect setting. Material and Methods Six men with newly diagnosed MRI-visible and biopsy-concordant clinically significant PCa were enrolled and completed the study. Eight lesions classified as PI-RADS 3–5 were focally ablated using TULSA. One- and three-week follow-up MRI scans were performed between TULSA and robot-assisted laparoscopic prostatectomy. Results TULSA-related hemorrhage was detected as a subtle T1 hyperintensity and more apparent T2 hypointensity in the MRI. Both prostate volume and non-perfused volume (NPV) markedly increased after TULSA at one week and three weeks after treatment, respectively. Lesion apparent diffusion coefficient values increased one week after treatment and decreased nearing the baseline values at the three-week MRI follow-up. Conclusion The optimal timing of MRI follow-up seems to be at the earliest at three weeks after treatment, when the post-procedural edema has decreased and the NPV has matured. Diffusion-weighted imaging has little or no added diagnostic value in the subacute setting.

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