Transcript
It's my pleasure to be here, to share some of our experience with the SBRT program for radioresistant renal cell carcinoma. And we are very lucky at Methodist Hospital for a very unique opportunity because we have a very active GU oncology program and allowing me to share this experiment. The older studies especially concentrate on translational program like Dr. Sorbert [SP] just mentioned.
Renal cell carcinoma is a very unique malignancy. As you can see here it's very vascular and clear cell subtype is one of the most common subtype. It has high propensity to involve any organ, every organ that you can think of in human body. This is a study in 2000. Literally, it can go to lung, bone, liver, brain, abdomen, lymph node, and skin. This tumor accounts for about 3% of all malignancy. It is the sixth leading cause of death in the United States.
The incidence of this tumor is increasing, and part of the reason is because of the use of imaging. This year, there will be about 39,000 new cases. A third of those patients will die. Now, traditionally we consider renal cell carcinoma radioresistant. Conventional RT is not very effective for both primary or metastatic disease. However, the molecular basis of radioresistance in this tumor is not well understood. As we all know from this meeting, SBRT allow us to deliver very high dose per fraction, what we call a biologically more potent dose.
As I see, this is possible new technique of delivering to overcome radioresistance in renal cell carcinoma. That's how I started this program. And has been mentioned yesterday and today, there are now three molecular targeted therapy approved by FDA and renal cell carcinoma patients with metastasis are surviving longer. Those drugs, including sorafenib, sunitinib, and most recently parasol, which is a mTOR inhibitor.
So this communication I'm presenting our SBRT program for renal cell carcinoma from a gene expression profiling preclinical in-vitro, in-vivo model using a human RCC cell line and a nude mouse xenograft model to clinical studies. The gene expression studies involving a CRL 1932, which is a very high-grade clear cell carcinoma. And they were irradiated to different regimen to great perfection for five continuous days versus 10Gy single fraction. We extract total RNA prior to and 24 hours after irradiation and gene expression profiling was performed using Affymetrix GeneChip array as shown in this slide.
I will not have time to go in-depth. Basically to highlight to you in the gene expression profiling results, the genes that are regulated, typically we represent in red and under-expressed, represented in green. In the in-vitro model, same thing, human reno cell line were radiated either with 2Gy or 15Gy/fraction compared to control various assay was performed to evaluate anti-tumor efficacy.
In-Vivo subcutaneous human RCC model in nude mice was irradiated with 2Gy/fraction versus 15Gy/fraction compared to control. Tumor growth delay assay was used to investigate anti-tumor effects of irradiation. And in clinical studies, we evaluated a patient with primary RCC and metastatic RCC involving cranial and extra-cranial sites treated with SRS and SBRT using Novalis system.
Results. Gene expression profiling three groups. Using the three-fold increased threshold analysis. In addition to 31 common genes involved, there were 42 and 66 separate or different genes changed in the conventional and SBRT fractionation schema respectively as shown here. If you lower the analysis of fold change, you will see more genes' difference.
We are also currently evaluating various important pathway involving radiation such as hypoxia pathway, AKT pathway, and compare conventional versus SBRT fractionation. In-vitro, we observe more cell kill in the SBRT group when compared to lower dose and control. I'm gonna show you the first assay, we use cell density assay. And as you can see here, the cell that treated were 15Gy and has basically more cell killed compared to lower fraction 2Gy and control.
Clonogenic assay, we also have observed the same results. There are more cell kill with the SBRT type of fractionation compared to conventional fractionation and control. In vivo experiments involving the human RCC Xenograph on the subcutaneous model in the mice three groups control, 2Gy times 15f, 15Gy times 2f. And what we observe is the control animal demonstrate a progressive tumor growth and SBRT group demonstrated rapid regression of tumor. The lower, more conventional dose group show initial slow progression followed by a rapid progression of tumor.
We're going to show you in this animal study. This is controlled. As you can see, there's a subcutaneous model on the highlight, and you can see tumor growth to this size, and we have to sacrifice them according to the animal IRB rule. And then this is a conventional, a 2Gy times 15f, and you can see initially control the tumor, but later on the tumor growing back.
SPRT group, you can see very nice a control of the tumor. Also of note, we noticed some acute skin reaction in week two, and later on this reaction heal nicely. At the moment, we are doing a lot more IHC immunohistochemistry study, and also gene expression profiling on this preclinical model. And the result is represented here. As you can see the control group, conventional group, initial control, later rapid progression of the tumor and basically SBRT group, the tumor is controlled over this period of time.
Clinical data, this is our initial experience is now published. And our initial experience treating about 20 patient including patient with metastatic disease, as well as a primary medically inoperable renal cell carcinoma. First is the renal cell brain met. We have published our data and basically, we observe single-fraction SRS provided the best result in patient with RCC brain met maybe related to the smaller size when compared to those of extracranial metastatic lesion.
There was also evidence to show pathologic complete response in the brain metastatic lesion, treated with SRS, which I'm gonna show you. In a smaller lesion, we usually see this, an imaging complete response after SRS to this one-centimeter brain met. This is a case that a patient initially have resected brain met renal cell, which we have the pathology later on, come back with tumor lesion treated with 22Gy single fraction, six months later develop some radiation changes versus progression of disease. However, the patient could not tolerate oral steroids leading to resection by our neurosurgeon and this is what we see.
This is the initial high-grade Fuhrman grade 3 clear cell RCC at the time of resection. After radiosurgery, you see necrotic tumor, and also residual vascular outline compared to the initial very vascular tumor. And of the 30 patients, this is in press right now that we observed 25 patients with a brain met RCC showing decreasing or stable lesion. Five of them show some increase in the size and underwent resection. Again, all those five-show pathology review necrosis in more than 99% of specimen with no viable RCC that we can see.
Again, our initial experience has been published SBRT to primary RCC and various metastatic sites. We yield a good local control, 87%, and symptom palliation in about 93% with almost no treatment-related toxicity. In this, audience know about the system. This is to show you a couple of immobilization and the device that we use at our institution. This is a case of a head and neck and metastatic disease after 17 years after initial nephrectomy. And this is a high-grade clear cell RCC treated with SBRT and have imaging complete response. This involved the nasal and also the sinuses.
This is a case of lung and mediastinal RCC. We use 4D-CT and in the audience, my physicists, Dr. Chuck Blaauw [SP] and Susan Reginson [SP] helped me to create ITV while we treat this. And this is a case the patient have local progression of metastatic RCC in the paratracheal area not responding to systemic treatment. And her last side effects on systemic treatment, significant dysphagia, and weight loss, and treated with 10Gy times 4f eight to dynamic conformal ox. Also, noticed the pacemaker that we avoided.
And this is actually the post before and after SBRT 10Gy x 4, significant improvement on imaging and his dysphagia improve and almost no side effects that we could see. A liver case, same thing, metastatic RCC. Pre-SBRT, this particular RCC show up on PET and we treat with the 10Gy times 5f, six dynamic conformal arc, and post-SBRT PET, complete response.
And yesterday has been addressed by Dr. Angelov on the RCC on the spine cases. We do the same, and we also observe very good clinical response in the bone, spine, and also pelvis cases. This patient we're trying to avoid the bowel. We only delivered 8Gy times 5 and gained good pain relief. A case of a spinal in the same patient with a spine involvement 8Gy times 5 achieved a good pain relief.
This is a case of a patient with a medically inoperable metastatic renal cell carcinoma with a primary intact, primary RCC intact with severe pain. And this case, we also do a PET CT and the showing a hot spot within the tumor like so. So what we did a little different, we use a PET CT fusion with the Novalis system. We treat the whole...let me show you the next slide. You can see the normal kidney. This is the RCC kidney mass and PET avid area within the kidney mass. We treat, this is our initial experience, so we only do 8Gy times 3f fraction to the whole RCC tumor, and then the PET. Yes, I'm almost done.
And the PET avid area, we basically boosted a further 4Gy times 3f, and the patient also have, at the same time, had metastatic disease in the sacrum. Also treated, this is our initial fractionation. We are dose escalating in this group of patient, 8Gy times 3 and achieve good palliation. We use actually, I didn't show you earlier. We put Visicoil in the RCC and then using this as image guidance with the Novalis system. And we also do 4D CT to look at the kidney motion.
And the post-treatment, the patient with a medically inoperable RCC, we even looked at the kidney function. There was no deterioration, and the tumor is also controlled and pain relief. So in conclusion, SBRT can cause significant tumor cell death in radio-resistant RCC, in-vitro, in-vivo and clinical studies I've shared with you. And this is very effective and safe in my opinion, for RCC, in terms of local control and symptom palliation. We are embarking on the prospective clinical trials and in combination with more newer targeted therapy.
Gene expression profiling, we saw RCC after SBRT are very interesting and may shed some light on the mechanism of action. And also, hopefully, we can elucidate the molecular basis of radio-resistance in this tumor. Further identification of specific genes responsible for radioresistance in RCC will be very beneficial to serve as targets for radiosensitization, especially with the combination with radiation.
This is my last slide. This is my contribution to New England Journal of Medicine. And I'm going to end by quoting you the last two sentences here. "SBRT, which allow for more conformal high dose extracranial radiotherapy delivery, may expand the role of radiation in treating both metastatic and non-operative primary cases. Radiation combined with biologic agents, such as mTOR inhibitor or sorafenib tyrosine kinase inhibitor holds promise in overcoming RCC radioresistance and certainly is actively investigated in my institution."
I have to take this opportunity to thank Novalis Circle organizing committee, and also my physicists Chuck Blaauw, and Susan who have spent hours planning all these cases. Thank you.
Renal cell carcinoma is a very unique malignancy. As you can see here it's very vascular and clear cell subtype is one of the most common subtype. It has high propensity to involve any organ, every organ that you can think of in human body. This is a study in 2000. Literally, it can go to lung, bone, liver, brain, abdomen, lymph node, and skin. This tumor accounts for about 3% of all malignancy. It is the sixth leading cause of death in the United States.
The incidence of this tumor is increasing, and part of the reason is because of the use of imaging. This year, there will be about 39,000 new cases. A third of those patients will die. Now, traditionally we consider renal cell carcinoma radioresistant. Conventional RT is not very effective for both primary or metastatic disease. However, the molecular basis of radioresistance in this tumor is not well understood. As we all know from this meeting, SBRT allow us to deliver very high dose per fraction, what we call a biologically more potent dose.
As I see, this is possible new technique of delivering to overcome radioresistance in renal cell carcinoma. That's how I started this program. And has been mentioned yesterday and today, there are now three molecular targeted therapy approved by FDA and renal cell carcinoma patients with metastasis are surviving longer. Those drugs, including sorafenib, sunitinib, and most recently parasol, which is a mTOR inhibitor.
So this communication I'm presenting our SBRT program for renal cell carcinoma from a gene expression profiling preclinical in-vitro, in-vivo model using a human RCC cell line and a nude mouse xenograft model to clinical studies. The gene expression studies involving a CRL 1932, which is a very high-grade clear cell carcinoma. And they were irradiated to different regimen to great perfection for five continuous days versus 10Gy single fraction. We extract total RNA prior to and 24 hours after irradiation and gene expression profiling was performed using Affymetrix GeneChip array as shown in this slide.
I will not have time to go in-depth. Basically to highlight to you in the gene expression profiling results, the genes that are regulated, typically we represent in red and under-expressed, represented in green. In the in-vitro model, same thing, human reno cell line were radiated either with 2Gy or 15Gy/fraction compared to control various assay was performed to evaluate anti-tumor efficacy.
In-Vivo subcutaneous human RCC model in nude mice was irradiated with 2Gy/fraction versus 15Gy/fraction compared to control. Tumor growth delay assay was used to investigate anti-tumor effects of irradiation. And in clinical studies, we evaluated a patient with primary RCC and metastatic RCC involving cranial and extra-cranial sites treated with SRS and SBRT using Novalis system.
Results. Gene expression profiling three groups. Using the three-fold increased threshold analysis. In addition to 31 common genes involved, there were 42 and 66 separate or different genes changed in the conventional and SBRT fractionation schema respectively as shown here. If you lower the analysis of fold change, you will see more genes' difference.
We are also currently evaluating various important pathway involving radiation such as hypoxia pathway, AKT pathway, and compare conventional versus SBRT fractionation. In-vitro, we observe more cell kill in the SBRT group when compared to lower dose and control. I'm gonna show you the first assay, we use cell density assay. And as you can see here, the cell that treated were 15Gy and has basically more cell killed compared to lower fraction 2Gy and control.
Clonogenic assay, we also have observed the same results. There are more cell kill with the SBRT type of fractionation compared to conventional fractionation and control. In vivo experiments involving the human RCC Xenograph on the subcutaneous model in the mice three groups control, 2Gy times 15f, 15Gy times 2f. And what we observe is the control animal demonstrate a progressive tumor growth and SBRT group demonstrated rapid regression of tumor. The lower, more conventional dose group show initial slow progression followed by a rapid progression of tumor.
We're going to show you in this animal study. This is controlled. As you can see, there's a subcutaneous model on the highlight, and you can see tumor growth to this size, and we have to sacrifice them according to the animal IRB rule. And then this is a conventional, a 2Gy times 15f, and you can see initially control the tumor, but later on the tumor growing back.
SPRT group, you can see very nice a control of the tumor. Also of note, we noticed some acute skin reaction in week two, and later on this reaction heal nicely. At the moment, we are doing a lot more IHC immunohistochemistry study, and also gene expression profiling on this preclinical model. And the result is represented here. As you can see the control group, conventional group, initial control, later rapid progression of the tumor and basically SBRT group, the tumor is controlled over this period of time.
Clinical data, this is our initial experience is now published. And our initial experience treating about 20 patient including patient with metastatic disease, as well as a primary medically inoperable renal cell carcinoma. First is the renal cell brain met. We have published our data and basically, we observe single-fraction SRS provided the best result in patient with RCC brain met maybe related to the smaller size when compared to those of extracranial metastatic lesion.
There was also evidence to show pathologic complete response in the brain metastatic lesion, treated with SRS, which I'm gonna show you. In a smaller lesion, we usually see this, an imaging complete response after SRS to this one-centimeter brain met. This is a case that a patient initially have resected brain met renal cell, which we have the pathology later on, come back with tumor lesion treated with 22Gy single fraction, six months later develop some radiation changes versus progression of disease. However, the patient could not tolerate oral steroids leading to resection by our neurosurgeon and this is what we see.
This is the initial high-grade Fuhrman grade 3 clear cell RCC at the time of resection. After radiosurgery, you see necrotic tumor, and also residual vascular outline compared to the initial very vascular tumor. And of the 30 patients, this is in press right now that we observed 25 patients with a brain met RCC showing decreasing or stable lesion. Five of them show some increase in the size and underwent resection. Again, all those five-show pathology review necrosis in more than 99% of specimen with no viable RCC that we can see.
Again, our initial experience has been published SBRT to primary RCC and various metastatic sites. We yield a good local control, 87%, and symptom palliation in about 93% with almost no treatment-related toxicity. In this, audience know about the system. This is to show you a couple of immobilization and the device that we use at our institution. This is a case of a head and neck and metastatic disease after 17 years after initial nephrectomy. And this is a high-grade clear cell RCC treated with SBRT and have imaging complete response. This involved the nasal and also the sinuses.
This is a case of lung and mediastinal RCC. We use 4D-CT and in the audience, my physicists, Dr. Chuck Blaauw [SP] and Susan Reginson [SP] helped me to create ITV while we treat this. And this is a case the patient have local progression of metastatic RCC in the paratracheal area not responding to systemic treatment. And her last side effects on systemic treatment, significant dysphagia, and weight loss, and treated with 10Gy times 4f eight to dynamic conformal ox. Also, noticed the pacemaker that we avoided.
And this is actually the post before and after SBRT 10Gy x 4, significant improvement on imaging and his dysphagia improve and almost no side effects that we could see. A liver case, same thing, metastatic RCC. Pre-SBRT, this particular RCC show up on PET and we treat with the 10Gy times 5f, six dynamic conformal arc, and post-SBRT PET, complete response.
And yesterday has been addressed by Dr. Angelov on the RCC on the spine cases. We do the same, and we also observe very good clinical response in the bone, spine, and also pelvis cases. This patient we're trying to avoid the bowel. We only delivered 8Gy times 5 and gained good pain relief. A case of a spinal in the same patient with a spine involvement 8Gy times 5 achieved a good pain relief.
This is a case of a patient with a medically inoperable metastatic renal cell carcinoma with a primary intact, primary RCC intact with severe pain. And this case, we also do a PET CT and the showing a hot spot within the tumor like so. So what we did a little different, we use a PET CT fusion with the Novalis system. We treat the whole...let me show you the next slide. You can see the normal kidney. This is the RCC kidney mass and PET avid area within the kidney mass. We treat, this is our initial experience, so we only do 8Gy times 3f fraction to the whole RCC tumor, and then the PET. Yes, I'm almost done.
And the PET avid area, we basically boosted a further 4Gy times 3f, and the patient also have, at the same time, had metastatic disease in the sacrum. Also treated, this is our initial fractionation. We are dose escalating in this group of patient, 8Gy times 3 and achieve good palliation. We use actually, I didn't show you earlier. We put Visicoil in the RCC and then using this as image guidance with the Novalis system. And we also do 4D CT to look at the kidney motion.
And the post-treatment, the patient with a medically inoperable RCC, we even looked at the kidney function. There was no deterioration, and the tumor is also controlled and pain relief. So in conclusion, SBRT can cause significant tumor cell death in radio-resistant RCC, in-vitro, in-vivo and clinical studies I've shared with you. And this is very effective and safe in my opinion, for RCC, in terms of local control and symptom palliation. We are embarking on the prospective clinical trials and in combination with more newer targeted therapy.
Gene expression profiling, we saw RCC after SBRT are very interesting and may shed some light on the mechanism of action. And also, hopefully, we can elucidate the molecular basis of radio-resistance in this tumor. Further identification of specific genes responsible for radioresistance in RCC will be very beneficial to serve as targets for radiosensitization, especially with the combination with radiation.
This is my last slide. This is my contribution to New England Journal of Medicine. And I'm going to end by quoting you the last two sentences here. "SBRT, which allow for more conformal high dose extracranial radiotherapy delivery, may expand the role of radiation in treating both metastatic and non-operative primary cases. Radiation combined with biologic agents, such as mTOR inhibitor or sorafenib tyrosine kinase inhibitor holds promise in overcoming RCC radioresistance and certainly is actively investigated in my institution."
I have to take this opportunity to thank Novalis Circle organizing committee, and also my physicists Chuck Blaauw, and Susan who have spent hours planning all these cases. Thank you.