Raquibul Hannan, MD, PhD
A recent study demonstrated that treatment with a focused form of stereotactic radiation led to a greater than 90% rate of local control in patients with metastatic renal cell carcinoma (RCC), according to findings published in the International Journal of Radiation Oncology, Biology, and Physics
“We have data that show that RCC responds very well to this stereotactic radiation. By giving high doses during treatment days, we can potentially cure RCC more effectively than with conventional treatments,” said senior study author Raquibul Hannan, MD, PhD.
In an interview with OncLive
, Hannan, an assistant professor and radiation oncologist at The University of Texas Southwestern Medical Center, discussed the benefits of using stereotactic radiation for patients with RCC and highlighted ongoing trials examining the modality.
OncLive: Can you please discuss this study?
: This is a retrospective study, where we viewed our experience over the past 5 to 7 years. We were one of the pioneers in studying stereotactic radiation, which is a very focused form of radiation. Because of this, we can deliver a dose without creating normal tissue damage, making the side effects very good.
This form of radiation allows us to treat the tumor anywhere in the body. With old conventional forms of radiation, you couldn't give a very high dose to the tumor that is right next to the spinal cord or the stomach because they are very radiosensitive structures.
Essentially, the tumor can be anywhere in the body and we can effectively treat it. This is especially important for patients with RCC because it is known to be resistant to the conventional forms of radiation. With conventional forms, you're giving small amounts of doses which can last from 5 to 7 weeks, whereas the stereotactic radiation lasts from 3 to 5 days.
We have data that shows that RCC responds very well to this stereotactic radiation. By giving high doses during treatment days, we can potentially cure RCC more effectively than with conventional treatments.
We've been studying stereotactic radiation in our institution for quite some time now. This study shows that in more than 90% of cases, we can cure the tumor when we use stereotactic radiation in the setting of kidney cancer.
The only times where the patients failed was when the tumor was in the spinal setting. Another area that saw failure was in patients that had prior multiple lines of systemic therapy since this has made the tumor more resistant. Those were the few failures we’ve seen which we have analyzed to determine how to apply stereotactic radiation to patients more appropriately.
Based on this study, if a patient has already failed multiple lines of systemic therapy, the patient needs to receive higher doses of stereotactic radiation to cure these patients. In this study, we were able to develop specific dose recommendations based on our analysis. Additionally, I have 4 ongoing prospective clinical trials to apply stereotactic radiation effectively to patients with kidney cancer.
How do the side effects of stereotactic radiation compare to conventional treatments?
The chances of side effects were much lower with stereotactic radiation compared to conventional treatments. The conventional radiation is a bigger field of radiation, meaning radiation is given to normal tissue and is not able to spare it with a more focused application, such as what we have with stereotactic radiation. Overall, there were only a few grade 3 toxicities.
The side effects are so low, making the quality of life much better. Patients are able to enjoy their daily activities, whereas chemotherapy and systemic therapy see side effects of high blood pressure, tiredness, fatigue, rashes, and other effects ultimately decreasing the quality of life. In one of the current clinical trials, we want to see if we can safely delay the start of the systemic therapy by treating metastatic sites with stereotactic radiation.
What patient population saw the most beneficial response to stereotactic radiation?
We applied stereotactic radiation in patients with metastatic RCC limited to 1 to 5 sites of disease. If a patient has completely widespread metastatic disease, we cannot possibly treat all of those sites with stereotactic radiation. If they have a limited number of metastatic disease, then we can treat each of those with stereotactic radiation. This is one of the reasons we are calling this a noninvasive form of surgery. If a patient has 1 to 5 sites, we can still effectively treat them, hopefully giving these patients somewhat of a curative chance.