Reirradiation of locally recurrent prostate cancer with Cyber-knife® System or Volumetric Modulated Arc Therapy (VMAT) and IGRT-Clarity®: outcomes, toxicities and dosimetric evalu-ation
Creators
- 1. Department of Radiation Oncology, Istituto Nazionale Tumori - IRCCS - Fondazione G. Pascale, Napoli, Italia
- 2. Departimento di Scienze Biomediche Avanzate, Università degli Studi di Napoli Federico II, 80131 Napoli
- 3. Epidemiology and Biostatistics Unit, Istituto Nazionale Tumori - IRCCS - Fondazione G. Pascale, Napoli, Italia
- 4. Departmental Unit Of Clinical and Experimental Uro-Andrologic Oncology, Istituto Nazionale Tumori - IRCCS - Fondazione G. Pascale, Napoli, Italia
- 5. Department of Uro-Gynecological, Istituto Nazionale Tumori - IRCCS - Fondazione G. Pascale, Napoli, Italia
Description
Abstract: The management of prostate cancer recurrence following external beam radiotherapy is not defined yet. Stereotaxic body re-irradiation therapy, has shown encouraging results for local and biochemical control. From April 2017 to December 2020, 29 patients with prostate cancer recurrence were collected, joining the retrospective studies CyPro (prot. 46/19 OSS) and CLARO (Prot.19/20 OSS) trials. Patients were treated with Cyberknife (CK), or VMAT (Volumetric Modulated Arc Technique) system by IGRT (Image-Guided Radiation Therapy)/Clarity. By comparing the re-irradiation of two groups, we investigated urinary (GU), rectal (GI) toxicities and biochemical control. Furthermore, we dosimetrically compared the two techniques by rival plans. The VMAT-IGRT Clarity treatments were replanned with an optimized template developed for prostate VMAT-SBRT in FFF mode keeping the dose and fractionation scheduled for CK Group at 30 Gy in 5fx, prescribing at 80% isodose. 23% of patients experiencing grade 2 acute GU and 6% grade 2 acute GI in the CK group. 17% Acute GU toxicity was recorded in the VMAT-Clarity group. 8% grade 2 late toxicity was recorded in the VMAT-Clarity group. The dosimetric analysis shows that the VMAT-FFF will allow to deliver a dose biologically equivalent than with the CK, and reduce the toxicities that could arise.
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