Real time 3-D interactive seed placement or preplanning: A comparison of two brachytherapy techniques in the treatment of localized prostate cancer

Purpose: Image-guided radiotherapy (IGRT) is central to the safe and effective delivery of ultrahypofractionated (UF) stereotactic body radiotherapy (SBRT) for localized prostate cancer. However, the optimal IGRT modality remains uncertain. We aim to study the safety of performing UF-SBRT using cone-beam computed tomography (CBCT) and real-time transperineal ultrasound (TPUS) monitoring. Materials and Methods: We retrospectively review the medical records of 26 patients who had received UF-SBRT for intermediate risk localized prostate cancer in our institution from October 2018 to December 2020. All patients were treated with SBRT without fiducial marker and received 35–40 Gy to the clinical target volume in 5 fractions over 2–5 weeks. CBCT was used to correct for interfraction displacement while intrafraction displacement of the prostate gland was monitored using Elekta Clarity Autoscan TPUS with 4 mm isotropic warning level. All patients also received neoadjuvant and concurrent androgen deprivation therapy for a total of 6 months. The primary endpoints were incidence of acute toxicities and patient reported urinary toxicities in terms of the International Prostate Symptom Score: before (IPSS1), at the completion of (IPSS2), and at 3–6 months (IPSS3) after SBRT. Results: All men were treated and followed up for at least 3 months after SBRT. Patients experienced transient worsening of their urinary symptoms at the end of SBRT but they usually recovered in 3–6 months afterwards. The median IPSS1, IPSS2, and IPSS3 were 12, 12.5, and 8, respectively. One patient developed grade 3 rectal bleeding which was related to underlying hemorrhoid. No other grade 3–4 acute toxicity was observed. Conclusion: It appears safe to deliver UF-SBRT without fiducial marker for prostate cancer patients using CBCT and non-invasive hybrid imaging modalities for positioning and tracking. Longer follow-up is necessary to monitor the treatment efficacy and long-term toxicities.

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Superiority of Real-Time Adaptive Interstitial High-Dose-Rate Brachytherapy for Localized Prostate Cancer—Five- and 8-Year Outcomes of Kiel University Hospital Protocols

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/j.ijrobp.2016.06.1321 ◽

2016 ◽

Vol 96 (2) ◽

pp. E277-E278

Author(s):

R. Galalae ◽

C. Schroeder ◽

F. Geiger ◽

F.A. Siebert ◽

J.R. Schultze ◽

...

Keyword(s):

Prostate Cancer ◽

Dose Rate ◽

Real Time ◽

High Dose Rate ◽

University Hospital ◽

Localized Prostate Cancer ◽

High Dose ◽

High Dose Rate Brachytherapy ◽

Hospital Protocols

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Target localization and real-time tracking using the Calypso 4D localization system in patients with localized prostate cancer

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/j.ijrobp.2006.01.050 ◽

2006 ◽

Vol 65 (2) ◽

pp. 528-534 ◽

Cited By ~ 317

Author(s):

Twyla R. Willoughby ◽

Patrick A. Kupelian ◽

Jean Pouliot ◽

Katsuto Shinohara ◽

Michelle Aubin ◽

...

Keyword(s):

Prostate Cancer ◽

Real Time ◽

Target Localization ◽

Localized Prostate Cancer ◽

Localization System ◽

Real Time Tracking

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CyberKnife Radiotherapy for Localized Prostate Cancer: Rationale and Technical Feasibility

Technology in Cancer Research & Treatment ◽

10.1177/153303460300200104 ◽

2003 ◽

Vol 2 (1) ◽

pp. 25-29 ◽

Cited By ~ 122

Author(s):

Christopher R. King ◽

Joerg Lehmann ◽

John R. Adler ◽

Jenny Hai

Keyword(s):

Prostate Cancer ◽

Real Time ◽

Dose Escalation ◽

Target Position ◽

Localized Prostate Cancer ◽

Robotic Arm ◽

Study Patient ◽

Tumor Control ◽

Technical Feasibility ◽

Delivery Times

There is a clear dose response for localized prostate cancer radiotherapy and there probably is a radiobiological rationale for hypo-fractionation. Combining the two should maximize tumor control and increase the therapeutic ratio. This study examines the rationale and technical feasibility of CyberKnife radiotherapy (a robotic arm-driven linear accelerator) for localized prostate cancer. Its ability to deliver non-coplanar non-isocentric arcs can yield maximally conformal isodoses. It is the only integrated system capable of target position verification and real-time tracking during delivery of conformal stereotactic radiotherapy. Inverse planning with the CyberKnife is used to design a course of radiotherapy for localized prostate cancer. Fiducial markers within the gland are used to verify organ position and track organ motion via an orthogonal pair of electronic x-ray imaging devices and provide real-time feedback correction to the robotic arm during delivery. Conformal isodose curves and dose volume histograms (DVH) are used to compare with an optimized Intensity-Modulated Radiotherapy (IMRT) plan actually delivered to the study patient based upon CT scan-derived organ volumes. The CyberKnife can produce superior DVHs for sparing of rectum and bladder and excellent DVHs for target coverage compared with IMRT, and possesses dose heterogeneities to the same degree as IMRT plans. Because of the significantly longer delivery times required it would be best suited for hypo-fractionated regimens. Such dose regimens might allow for biologically equivalent dose escalation without increased normal tissue toxicity. Since the CyberKnife can verify organ position and motion and correct for this in real-time it is the ideal means of achieving such excellent DVHs without a compromise in doses to normal tissues. These capabilities are essential if one contemplates hypo-fractionated regimens with large dose-per-fraction sizes (>5Gy to 10Gy) and dose-escalation.

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