B. mir Khan1, N. Pervez2, H. AlSayegh3, M. Vellengara2, S. Usmani1, I. Al Amri4, M. Alfishawy4, and M. Al Harthy3; 1Sultan Qaboos Comprehensive Cancer Care and Research Centre (SQCCCRC),, Muscat, Oman, 2Sultan Qaboos Comprehensive Cancer Centre, Sultanate of Oman, muscat, Oman, 3Sultan Qaboos Comprehensive Cancer Centre, Sultanate of Oman, Muscat, Oman, 4Sultan Qaboos Comprehensive Cancer Care and Research Centre (SQCCCRC), Muscat, Oman
Purpose/Objective(s):De novo metastatic prostate cancer accounts for 5–10% of all prostate cancer (PC) diagnoses but it is responsible for nearly 50% of PC-related deaths. There is no current agreement on standard of care for these patients. We treated de novo low burden metastatic patients with Radical doses of radiotherapy to primary and metastatic sites concomitantly. Patients also received Luteinizing Hormone Releasing Hormone (LHRH) ± Abiraterone (with Prednisolone) or Enzalutamide. Here we are reporting early results Materials/
Methods: All 21 patients treated from August 2021 to October 2023 were analysed. Patients were staged using CT and/or MRI, and/or PSMA PET-CT. Patient characteristics, radiation doses/techniques, treatment tolerance and toxicities data were prospectively collected. Toxicities were recorded weekly during radiotherapy and every 3 months thereafter using CTCAE v5.0. PSA was collected on every follow up visit. 19 patients received moderately hypo-fractionated radiotherapy, 68 Gy in 25 fractions, and 2 received conventional doses, 78 Gy in 39 fractions to the gross pelvic disease (Prostate ± Seminal vesicle ± Gross Pelvic Nodes). Para-aortic nodes where involved, received 60 Gy in 25 fractions. Elective nodes received 45 to 50 Gy in 25 fractions. Patients with distant bone metastatic sites were treated with SBRT 35 to 40 Gy in 5 consecutive fractions. Results: Median follow up was 21.6 months (range: 7-37). Median age was 70.08 years (range: 48.26-96.42). Median initial PSA was 31.7 ng/ml (range: 13-182). Pelvic nodes(PLN) were involved in 18 (85.7%) of patients. Median numbers of PLN on PSMA-PET scan was 2 (range: 1 to 9). Largest nodal size was more than 1 cm in 8 (38%) patients. Para-aortic nodes(PALN) were involved in 9 (42.9%) of patients. Median numbers of PALN were 4.5 (range 1 to 12) on PSMA-PET scan. Four patients had bone metastasis in; left iliac, left pubis, ribs, right humerus with right iliac crest. All patient received LHRH while 15 (71.4%) received LHRH and Abi+P or Enza. Time from start of LHRH to start of radiation therapy was 2.5 months (range: 0-11). All the patients were in biochemical remission at the last follow up. 8 (38.1%) patients had undetectable PSA (< 0.006 ng/ml), 10 (47.6%) had PSA range from 0.006 to 0.2 ng/ml and 3 (14.3%) had PSA of > 0.2 ng/ml (max PSA 0.27 ng/ml). 13 (62%) patients had grade 1 and 1 (4.75%) had grade 2 acute genitourinary (GU) toxicity. 4 (19%) patients had grade 1 and 1 (4.75%) had grade 2 acute gastrointestinal (GI) toxicity. No other acute toxicities were observed. At the last follow up, 4 (19%) patients had grade 1 GU toxicity, and none had GI toxicity. Conclusion: Radical doses of radiation therapy to the primary and metastatic sites concomitantly in patients with low burden metastatic prostate cancer treated at our institution was well tolerated and resulted in a pronounced early PSA response in our study but Longer follow up and further prospective randomized trials are required and are underway
