ANZUP 2018 – Dr Tamim Niazi
Dr Tamim Niazi discusses prostate oligometastatic targeted therapy in castration resistant prostate cancer.
Talking Urology Podcast Transcript
ANZUP 2018 Interviews – Tamim Niazi
Joseph Ischia: Thank you, Tamim for joining us. You’ve come a long way from Montreal to join us here in Sydney. It’s a great pleasure to have you here. Can you please give us the key take home messages you want people to take-away from your talks?
Tamim Niazi: Thank you. It’s exciting to be here and I think stereotactic body radiotherapy of either localized prostate cancer or the oligometastatic disease has been gaining traction over the past three or four years. Two reasons for it, one, that now we have functional PET PSMAs that could detect oligometastasis that we could not detect before, and secondly, the advances in technology that now we can deliver very highly target therapy to this oligometastasis or even localized prostate cancer has allowed us to deliver these treatments very accurately and of course with the a high precision.
Joseph: Excellent. You gave, as you mentioned, your stereotactic treatment for oligometastatic disease, do you have any concerns about safety? I mean it appears to be some of the perfect treatment, isn’t it, you can just target the one thing you want and miss out on everything else. Any concerns about it?
Tamim: So, of course like every other treatment toxicity is at most important for delivery of such a treatment. It is highly targeted and the dose was in the target goes up to 30% to 40% above the 100% and image-guided radiation therapy has to be robust and to avoid the organs at risk to prevent toxicity is very important. If you look at the prostate cancer, the most important thing is that because of its low alpha/beta ratio, the dose we give for refraction of the stereotactic body radiotherapy is rather lower than other primary sites therefore if you look at the data the grade 2 in higher toxicity is pretty low, less than 34%.
Joseph: Excellent. And you are the PI on a study coming out of Canada looking at stereotactic radiation in castration-resistant prostate cancer oligometastatic disease, can you just tell us very briefly about that?
Tamim: So, it’s a phase II adaptive phase III trial where patients are randomized to either a center of care which is EDT plus Enzalutamide in this study and randomized to either SBRT or no SBRT and this is again for oligometastatic patients less than five metastases treated with SBRT.
Joseph: Okay. And do you think this makes any difference whether if it’s CRPC or hormone-sensitive cancer when they are looking at treating oligometastatic disease?
Tamim: Honestly, I do not think it makes any difference with respect to the dose or the capability of radiation therapy or the SBRT to control local disease. In hormone-sensitive prostate cancer, the controlled rate would probably be higher or longer as opposed to CRPC because other disease may pop up with the CRPC than hormone-sensitive. Again, the question is would patients who are hormone-sensitive and we have one or two or three oligomets, can we have a prolonged control or even potentially cure these patients? That would be the question to answer. This is our subsequent phase III trial that’s coming in probably fall this year.
Joseph: We are starting to see SBRT creep in sort of as a standard of care in oligometastatic disease. Do you think that’s reasonable or should they really be part of a trial?
Tamim: I think at present time there is no data, be it for hormone-sensitive or castration-resistant prostate cancer. I think this treatment should be offered in a clinical trial setting. We have to answer this question, although it is very targeted, there is still toxicity associated where the patient can have pathological fractures because of the soft tissue surroundings, so it’s not a very benign treatment that we can give for anybody without any evidence. I think we have to confirm the evidence and have a randomized clinical trial before it is adopted across the board.
Joseph: It is obviously your area of research and passion. What do you think is one of the biggest misconceptions about stereotactic radiation that you feel that you need to dismiss today?
Tamim: I think the misconception, I would not call it misconception, rather a confusion around SBRT or stereotactic body radiation therapy is that, could it replace local resection of the disease or not? That would be the biggest confusion or question. If you look at liver metastasis from colorectal cancer, the resection is always the primary modality. If resection cannot happen, then SBRT is happening. In prostate cancer I think most of the sites I do not think will be resected by surgery and the approach most likely would be SBRT. I think it does a very good job and one of the, well, probably lack of understanding is that because of the low alpha/beta ratio of the prostate cancer, such a high dose per fraction of radiation therapy can have a local control of between 90% to 100% which is phenomenal for any metastasis.
Joseph: I see. You’re absolutely right we can’t just take out a humerus or a vertebra and we know from experience that taking out lymph nodes does not seem to be of any durable response, so it’s fantastic to have you here today, Tamim. We really appreciate you joining us in Sydney and I hope you have an enjoyable stay here and a safe trip back.
Tamim: Thank you very much. Thank you for having me. We were excited to be here.