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Ong WL, Allan Hupman M, Davidson M, Ruschin M, Detsky J, Liu S, Vesprini D, Loblaw A. Urethra contouring on computed tomography urethrogram versus magnetic resonance imaging for stereotactic body radiotherapy in prostate cancer. Clin Transl Radiat Oncol 2024; 45:100722. [PMID: 38234697 PMCID: PMC10792737 DOI: 10.1016/j.ctro.2023.100722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/24/2023] [Accepted: 12/30/2023] [Indexed: 01/19/2024] Open
Abstract
Accurate urethra contouring is critical in prostate SBRT. We compared urethra contouring on CT-urethrogram and T2-weighted MRI. The dice similarity coefficient, Jaccard index, Hausdorff distance and mean distance to agreement were evaluated. All four metrics indicate better agreement and less variability in urethra contouring on CT-urethrogram, compared to T2-weighted MRI.
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Affiliation(s)
- Wee Loon Ong
- Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Canada
- Alfred Health Radiation Oncology, Monash University, Melbourne, Australia
| | - M. Allan Hupman
- Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Canada
| | - Melanie Davidson
- Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Canada
| | - Mark Ruschin
- Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Canada
| | - Jay Detsky
- Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Canada
| | - Stanley Liu
- Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Canada
| | - Danny Vesprini
- Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Canada
| | - Andrew Loblaw
- Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Canada
- Department of Health Policy, Measurement and Evaluation, University of Toronto, Canada
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Prostatic urinary tract visualization with super-resolution deep learning models. PLoS One 2023; 18:e0280076. [PMID: 36607999 PMCID: PMC9821403 DOI: 10.1371/journal.pone.0280076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 12/20/2022] [Indexed: 01/07/2023] Open
Abstract
In urethra-sparing radiation therapy, prostatic urinary tract visualization is important in decreasing the urinary side effect. A methodology has been developed to visualize the prostatic urinary tract using post-urination magnetic resonance imaging (PU-MRI) without a urethral catheter. This study investigated whether the combination of PU-MRI and super-resolution (SR) deep learning models improves the visibility of the prostatic urinary tract. We enrolled 30 patients who had previously undergone real-time-image-gated spot scanning proton therapy by insertion of fiducial markers. PU-MRI was performed using a non-contrast high-resolution two-dimensional T2-weighted turbo spin-echo imaging sequence. Four different SR deep learning models were used: the enhanced deep SR network (EDSR), widely activated SR network (WDSR), SR generative adversarial network (SRGAN), and residual dense network (RDN). The complex wavelet structural similarity index measure (CW-SSIM) was used to quantitatively assess the performance of the proposed SR images compared to PU-MRI. Two radiation oncologists used a 1-to-5 scale to subjectively evaluate the visibility of the prostatic urinary tract. Cohen's weighted kappa (k) was used as a measure of agreement of inter-operator reliability. The mean CW-SSIM in EDSR, WDSR, SRGAN, and RDN was 99.86%, 99.89%, 99.30%, and 99.67%, respectively. The mean prostatic urinary tract visibility scores of the radiation oncologists were 3.70 and 3.53 for PU-MRI (k = 0.93), 3.67 and 2.70 for EDSR (k = 0.89), 3.70 and 2.73 for WDSR (k = 0.88), 3.67 and 2.73 for SRGAN (k = 0.88), and 4.37 and 3.73 for RDN (k = 0.93), respectively. The results suggest that SR images using RDN are similar to the original images, and the SR deep learning models subjectively improve the visibility of the prostatic urinary tract.
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Yoshimura T, Nishioka K, Hashimoto T, Seki K, Kogame S, Tanaka S, Kanehira T, Tamura M, Takao S, Matsuura T, Kobashi K, Kato F, Aoyama H, Shimizu S. A treatment planning study of urethra-sparing intensity-modulated proton therapy for localized prostate cancer. Phys Imaging Radiat Oncol 2021; 20:23-29. [PMID: 34693040 PMCID: PMC8517200 DOI: 10.1016/j.phro.2021.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 09/24/2021] [Accepted: 09/29/2021] [Indexed: 11/17/2022] Open
Abstract
US-IMPT can potentially reduce the risk of genitourinary toxicities. The urethral NTCP value in US-IMPT is significantly lower than in the clinical plan. TCP for CTV did not differ significantly between the clinical and US-IMPT plans.
Background and Purpose Urethra-sparing radiation therapy for localized prostate cancer can reduce the risk of radiation-induced genitourinary toxicity by intentionally underdosing the periurethral transitional zone. We aimed to compare the clinical impact of a urethra-sparing intensity-modulated proton therapy (US-IMPT) plan with that of conventional clinical plans without urethral dose reduction. Materials and Methods This study included 13 patients who had undergone proton beam therapy. The prescribed dose was 63 GyE in 21 fractions for 99% of the clinical target volume. To compare the clinical impact of the US-IMPT plan with that of the conventional clinical plan, tumor control probability (TCP) and normal tissue complication probability (NTCP) were calculated with a generalized equivalent uniform dose-based Lyman–Kutcher model using dose volume histograms. The endpoints of these model parameters for the rectum, bladder, and urethra were fistula, contraction, and urethral stricture, respectively. Results The mean NTCP value for the urethra in US-IMPT was significantly lower than that in the conventional clinical plan (0.6% vs. 1.2%, p < 0.05). There were no statistically significant differences between the conventional and US-IMPT plans regarding the mean minimum dose for the urethra with a 3-mm margin, TCP value, and NTCP value for the rectum and bladder. Additionally, the target dose coverage of all plans in the robustness analysis was within the clinically acceptable range. Conclusions Compared with the conventional clinically applied plans, US-IMPT plans have potential clinical advantages and may reduce the risk of genitourinary toxicities, while maintaining the same TCP and NTCP in the rectum and bladder.
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Affiliation(s)
- Takaaki Yoshimura
- Department of Health Sciences and Technology, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.,Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan
| | - Kentaro Nishioka
- Department of Radiation Medical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Takayuki Hashimoto
- Department of Radiation Medical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Kazuya Seki
- Division of Radiological Science and Technology, Department of Health Sciences, School of Medicine, Hokkaido University, Sapporo, Japan
| | - Shouki Kogame
- Division of Radiological Science and Technology, Department of Health Sciences, School of Medicine, Hokkaido University, Sapporo, Japan
| | - Sodai Tanaka
- Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan.,Faculty of Engineering, Hokkaido University, Sapporo, Japan
| | - Takahiro Kanehira
- Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan
| | - Masaya Tamura
- Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan
| | - Seishin Takao
- Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan.,Faculty of Engineering, Hokkaido University, Sapporo, Japan
| | - Taeko Matsuura
- Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan.,Faculty of Engineering, Hokkaido University, Sapporo, Japan
| | - Keiji Kobashi
- Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan
| | - Fumi Kato
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Japan
| | - Hidefumi Aoyama
- Department of Radiation Oncology, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Shinichi Shimizu
- Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan.,Department of Radiation Medical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan
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Yoshimura T, Nishioka K, Hashimoto T, Fujiwara T, Ishizaka K, Sugimori H, Kogame S, Seki K, Tamura H, Tanaka S, Matsuo Y, Dekura Y, Kato F, Aoyama H, Shimizu S. Visualizing the urethra by magnetic resonance imaging without usage of a catheter for radiotherapy of prostate cancer. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2021; 18:1-4. [PMID: 34258400 PMCID: PMC8254197 DOI: 10.1016/j.phro.2021.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 03/15/2021] [Accepted: 03/17/2021] [Indexed: 02/07/2023]
Abstract
Post urination MRI is useful for urethra-sparing radiotherapy treatment planning. This prospective clinical trial included 11 prostate cancer patients. Post urination MRI is the identification method of prostatic urinary tract in non-invasive manner.
The urethra position may shift due to the presence/absence of the catheter. Our proposed post-urination-magnetic resonance imaging (PU-MRI) technique is possible to identify the urethra without catheter. We aimed to verify the inter-operator difference in contouring the urethra by PU-MRI. The mean values of the evaluation indices of dice similarity coefficient, mean slice-wise Hausdorff distance, and center coordinates were 0.93, 0.17 mm, and 0.36 mm for computed tomography, and 0.75, 0.44 mm, and 1.00 mm for PU-MRI. Therefore, PU-MRI might be useful for identifying the prostatic urinary tract without using a urethral catheter. Clinical trial registration: Hokkaido University Hospital for Clinical Research (018-0221).
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Affiliation(s)
- Takaaki Yoshimura
- Department of Health Sciences and Technology, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.,Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan
| | - Kentaro Nishioka
- Department of Radiation Medical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Takayuki Hashimoto
- Department of Radiation Medical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Taro Fujiwara
- Department of Radiation Technology, Hokkaido University Hospital, Sapporo, Japan
| | - Kinya Ishizaka
- Department of Radiation Technology, Hokkaido University Hospital, Sapporo, Japan
| | - Hiroyuki Sugimori
- Department of Biomedical Science and Engineering, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan
| | - Shoki Kogame
- Division of Radiological Science and Technology, Department of Health Sciences, School of Medicine, Hokkaido University, Sapporo, Japan
| | - Kazuya Seki
- Division of Radiological Science and Technology, Department of Health Sciences, School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hiroshi Tamura
- Department of Radiation Technology, Hokkaido University Hospital, Sapporo, Japan
| | - Sodai Tanaka
- Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan.,Faculty of Engineering, Hokkaido University, Sapporo, Japan
| | - Yuto Matsuo
- Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan
| | - Yasuhiro Dekura
- Department of Radiation Oncology, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Fumi Kato
- Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Japan
| | - Hidefumi Aoyama
- Department of Radiation Oncology, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Shinichi Shimizu
- Department of Medical Physics, Hokkaido University Hospital, Sapporo, Japan.,Department of Radiation Medical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan.,Global Center for Biomedical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Japan
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Dekura Y, Nishioka K, Hashimoto T, Miyamoto N, Suzuki R, Yoshimura T, Matsumoto R, Osawa T, Abe T, Ito YM, Shinohara N, Shirato H, Shimizu S. The urethral position may shift due to urethral catheter placement in the treatment planning for prostate radiation therapy. Radiat Oncol 2019; 14:226. [PMID: 31831045 PMCID: PMC6909476 DOI: 10.1186/s13014-019-1424-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 11/20/2019] [Indexed: 12/31/2022] Open
Abstract
PURPOSE To determine the best method to contour the planning organ at risk volume (PRV) for the urethra, this study aimed to investigate the displacement of a Foley catheter in the urethra with a soft and thin guide-wire. METHODS For each patient, the study used two sets of computed tomography (CT) images for radiation treatment planning (RT-CT): (1) set with a Foley urethral catheter (4.0 mm diameter) plus a guide-wire (0.46 mm diameter) in the first RT-CT and (2) set with a guide-wire alone in the second CT recorded 2 min after the first RT-CT. Using three fiducial markers in the prostate for image fusion, the displacement between the catheter and the guide-wire in the prostatic urethra was calculated. In 155 consecutive patients treated between 2011 and 2017, 5531 slices of RT-CT were evaluated. RESULTS Assuming that ≥3.0 mm of difference between the catheter and the guide-wire position was a significant displacement, the urethra with the catheter was displaced significantly from the urethra with the guide-wire alone in > 20% of the RT-CT slices in 23.2% (36/155) of the patients. The number of patients who showed ≥3.0 mm anterior displacement with the catheter in ≥20% RT-CT slices was significantly larger at the superior segment (38/155) than at the middle (14/155) and inferior segments (18/155) of the prostatic urethra (p < 0.0167). CONCLUSIONS The urethral position with a Foley catheter is different from the urethral position with a thin and soft guide-wire in a significant proportion of the patients. This should be taken into account for the PRV of the urethra to ensure precise radiotherapy such as in urethra-sparing radiotherapy.
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Affiliation(s)
- Yasuhiro Dekura
- Department of Radiation Oncology, Graduate School of Medicine, Hokkaido University, North-15, West-7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Kentaro Nishioka
- Department of Radiation Medical Science and Engineering, Faculty of Medicine, Hokkaido University, North-15, West-7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan.
| | - Takayuki Hashimoto
- Department of Radiation Medicine, Faculty of Medicine, Hokkaido University, North-15, West-7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan.,Global Station for Biomedical Science and Engineering, Global Institute for Cooperative Research and Education, Hokkaido University, North-15, West-7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Naoki Miyamoto
- Global Station for Biomedical Science and Engineering, Global Institute for Cooperative Research and Education, Hokkaido University, North-15, West-7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan.,Department of Medical Physics, Hokkaido University Hospital, North-14, West-5, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Ryusuke Suzuki
- Department of Medical Physics, Hokkaido University Hospital, North-14, West-5, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Takaaki Yoshimura
- Department of Health Sciences and Technology, Faculty of Health Sciences, Hokkaido University, North-12, West-5, Kita-Ku, Sapporo, Hokkaido, 060-0812, Japan
| | - Ryuji Matsumoto
- Department of Renal and Genitourinary Surgery, Faculty of Medicine, Hokkaido University, North-15, West-7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Takahiro Osawa
- Department of Renal and Genitourinary Surgery, Faculty of Medicine, Hokkaido University, North-15, West-7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Takashige Abe
- Department of Renal and Genitourinary Surgery, Faculty of Medicine, Hokkaido University, North-15, West-7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Yoichi M Ito
- Department of Statistical Data Science, The Institute of Statistical Mathematics, 10-3, Midori-cho, Tachikawa, Tokyo, 190-0014, Japan
| | - Nobuo Shinohara
- Department of Renal and Genitourinary Surgery, Faculty of Medicine, Hokkaido University, North-15, West-7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Hiroki Shirato
- Department of Radiation Medicine, Faculty of Medicine, Hokkaido University, North-15, West-7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan.,Global Station for Biomedical Science and Engineering, Global Institute for Cooperative Research and Education, Hokkaido University, North-15, West-7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
| | - Shinichi Shimizu
- Department of Radiation Medical Science and Engineering, Faculty of Medicine, Hokkaido University, North-15, West-7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan.,Global Station for Biomedical Science and Engineering, Global Institute for Cooperative Research and Education, Hokkaido University, North-15, West-7, Kita-Ku, Sapporo, Hokkaido, 060-8638, Japan
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Sander L, Langkilde NC, Holmberg M, Carl J. MRI target delineation may reduce long-term toxicity after prostate radiotherapy. Acta Oncol 2014; 53:809-14. [PMID: 24358954 DOI: 10.3109/0284186x.2013.865077] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
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.
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Affiliation(s)
- Lotte Sander
- Department of Urology, Aalborg University Hospital , Aalborg , Denmark
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Korsager AS, Carl J, Østergaard LR. MR-CT registration using a Ni-Ti prostate stent in image-guided radiotherapy of prostate cancer. Med Phys 2014; 40:061907. [PMID: 23718598 DOI: 10.1118/1.4807087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE In image-guided radiotherapy of prostate cancer defining the clinical target volume often relies on magnetic resonance (MR). The task of transferring the clinical target volume from MR to standard planning computed tomography (CT) is not trivial due to prostate mobility. In this paper, an automatic local registration approach is proposed based on a newly developed removable Ni-Ti prostate stent. METHODS The registration uses the voxel similarity measure mutual information in a two-step approach where the pelvic bones are used to establish an initial registration for the local registration. RESULTS In a phantom study, the accuracy was measured to 0.97 mm and visual inspection showed accurate registration of all 30 data sets. The consistency of the registration was examined where translation and rotation displacements yield a rotation error of 0.41° ± 0.45° and a translation error of 1.67 ± 2.24 mm. CONCLUSIONS This study demonstrated the feasibility for an automatic local MR-CT registration using the prostate stent.
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Affiliation(s)
- Anne Sofie Korsager
- Department of Health Science and Technology, Aalborg University, Aalborg 9220, Denmark.
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Zaorsky NG, Harrison AS, Trabulsi EJ, Gomella LG, Showalter TN, Hurwitz MD, Dicker AP, Den RB. Evolution of advanced technologies in prostate cancer radiotherapy. Nat Rev Urol 2013; 10:565-79. [DOI: 10.1038/nrurol.2013.185] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Vainshtein J, Abu-Isa E, Olson KB, Ray ME, Sandler HM, Normolle D, Litzenberg DW, Masi K, Pan C, Hamstra DA. Randomized phase II trial of urethral sparing intensity modulated radiation therapy in low-risk prostate cancer: implications for focal therapy. Radiat Oncol 2012; 7:82. [PMID: 22681643 PMCID: PMC3408353 DOI: 10.1186/1748-717x-7-82] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 06/09/2012] [Indexed: 11/10/2022] Open
Abstract
Background Low-risk prostate cancer (PCa) patients have excellent outcomes, with treatment modality often selected by perceived effects on quality of life. Acute urinary symptoms are common during external beam radiotherapy (EBRT), while chronic symptoms have been linked to urethral dose. Since most low-risk PCa occurs in the peripheral zone (PZ), we hypothesized that EBRT using urethral sparing intensity modulated radiation therapy (US-IMRT) could improve urinary health-related quality of life (HRQOL) while maintaining high rates of PCa control. Methods Patients with National Comprehensive Cancer Network (NCCN) defined low-risk PCa with no visible lesion within 5 mm of the prostatic urethra on MRI were randomized to US-IMRT or standard (S-) IMRT. Prescription dose was 75.6 Gy in 41 fractions to the PZ + 3–5 mm for US-IMRT and to the prostate + 3 mm for S-IMRT. For US-IMRT, mean proximal and distal urethral doses were limited to 65 Gy and 74 Gy, respectively. HRQOL was assessed using the Expanded Prostate Cancer Index (EPIC) Quality of Life questionnaire. The primary endpoint was change in urinary HRQOL at 3 months. Results From June 2004 to November 2006, 16 patients were randomized, after which a futility analysis concluded that continued accrual was unlikely to demonstrate a difference in the primary endpoint. Mean change in EPIC urinary HRQOL at 3 months was −0.5 ± 11.2 in the US-IMRT arm and +3.9 ± 15.3 in the S-IMRT arm (p = 0.52). Median PSA nadir was higher in the US-IMRT arm (1.46 vs. 0.78, p = 0.05). At 4.7 years median follow-up, three US-IMRT and no S-IMRT patients experienced PSA failure (p = 0.06; HR 8.8, 95% CI 0.9–86). Two out of 3 patients with PSA failure had biopsy-proven local failure, both located contralateral to the original site of disease. Conclusions Compared with S-IMRT, US-IMRT failed to improve urinary HRQOL and resulted in higher PSA nadir and inferior biochemical control. The high rate of PSA failure and contralateral local failures in US-IMRT patients, despite careful selection of MRI-screened low-risk patients, serve as a cautionary tale for focal PCa treatments.
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Affiliation(s)
- Jeffrey Vainshtein
- Department of Radiation Oncology, University of Michigan Hospital, Ann Arbor, MI, USA.
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