“I think radiation therapy in bladder cancer could be divided into organ preservation, which is more for localized bladder cancer, as well as palliative approaches, which is very well known,” says Monika Joshi, MD, MRCP.
In this video, Monika Joshi, MD, MRCP, discusses the current state of radiotherapy for the treatment of bladder cancer. Joshi is an associate professor of medicine, Endowed Associate Professor in Cancer Clinical Investigation, Endowed Professor in Cancer Clinical Investigation, and an assistant professor in the department of medicine at Penn State Cancer Institute in Hershey, Pennsylvania.
What is the current state of radiotherapy for the treatment of bladder cancer?
I think radiation therapy in bladder cancer could be divided into organ preservation, which is more for localized bladder cancer, as well as palliative approaches, which is very well known. And then there is radiation alone in select patient populations, such as patients with T1 disease who are BCG unresponsive and are not really candidates for surgery. Organ preservation traditionally is done mainly for muscle-invasive bladder cancer. There have been numerous studies, thanks to our NRG colleagues, as well as colleagues from radiation oncology across the world. I think the landmark study was by Dr. James that was published in Lancet that showed improvement in 2-year local regional disease-free survival with the addition of chemotherapy. That's an important study. Their meta-analysis had also shown the non inferiority of hypofractionated radiation therapy vs standard fractionation. So all in all, I think for a muscle-invasive bladder cancer, T2 to T4 N0 type, if you're looking at the complete responses post chemo/RT, it could range from 59% to 88%. And we hope that 80% of these patients will maintain the bladder, whereas 20% may need surgery because of recurrence or other issues.
There are currently ongoing clinical studies that we'll talk about in our session including S1806 that is studying the role of immunotherapy in combination with chemo radiation therapy in muscle-invasive disease. I think that's a really important study to note. The role for radiation outside T2, T4 and if you step into the area of node positivity, I think it's still evolving. Certainly, there's feasibility of radiation for node-positive disease that has already been demonstrated by the IMPART study, which did include N1 to N3 patients. The study showed acceptable toxicity, no difference in N0 vs node positive and had a pretty decent 5-year bladder cancer-specific survival of 44%. So that was a good study to do. It showed 5-year overall survival of 34%. So that's an important area. We were one of the groups that actually led the first study combining immunotherapy and radiation. It was really an hypothesis-generating study that combined immunotherapy with radiation for localized and some node-positive patients who were not surgical candidates or couldn't get cisplatin. We also observed in that group, 1-year overall survival was pretty decent at 83.8%. And the node-positive patients did have similar outcomes when compared with node negative. It was a small study, so take it with a pinch of salt, but I think what it did suggest is that we need to do more studies in the space, which is why we have studies like E8185, which is looking for the role of chemo RT with or without immunotherapy node-positive patients.
This transcription has been edited for clarity.