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“There's not a perfect chemotherapy; there are a lot of different options, and then other factors to consider would be the field and the dose,” says Sophia Kamran, MD.
In this video, Sophia C. Kamran, MD, discusses options for bladder-sparing treatment regimens. Kamran is a radiation oncologist at the Massachusetts General Hospital Cancer Center and assistant professor of Radiation Oncology at Harvard Medical School, Boston, Massachusetts.
What are the optimal regimens if bladder preservation is chosen?
This is a little bit up in the air. There are a lot of options right now; we don't know if one option is better than the other. There are a few things that we have to think about when it comes to bladder preservation. First, we need to think about the dose of the radiation that we want to give. There's standard fractionation, which is usually 2 Gy per day, or can even be 1.8 Gy per day. So it can be 34 or 36 treatments, overall. There's a hypofractionated option, which can get the treatment done in a shorter amount of time, like 20 fractions; sometimes, we think about 25, just depending on the clinical scenario. Then, of course, there are the radiation fields. Are we treating just the bladder, or do we want to treat the bladder plus the pelvis? That's something else to think about. We have to think about the chemotherapy that's concurrent with the chemoradiation too. There isn't one perfect regimen. There have been multiple studies evaluating a lot of these different things, especially with regards to chemotherapy. We know that there are lots of different types of chemotherapy options, which is great, because it gives our medical oncologists a whole spectrum of chemotherapies to choose based on how the patient is presenting and whether they have really good kidney function, or if they have other comorbidities that you want to think about. There are options that make it [chemoradiation] much more accessible to a lot of different patients. When it comes to radiation dose, I think hypofractionation is an excellent treatment option, especially if it's more of a palliative treatment. But it's also great for definitive treatment. Right now, we're not doing hypofractionation if we want to combine it with immunotherapy, just because it's a higher dose per day, and there have been some early data demonstrating that when you do a higher dose per day and if you want to combine that with immunotherapy such as in the SWOG/NRG trial, there was a lot of toxicity so we had to back that off. So if you're going to combine radiation with immunotherapy, then we would definitely want to do the conventional fractionation, so doing it slower over multiple weeks, and not trying to speed that up. And then with regards to the radiation field, again, that's up in the air with regards to whether you treat the bladder or you treat the bladder plus some of the nearby lymph node sites. Again, we don't have an answer as to which one is better or if there is one that is better. There's been some conflicting data in the past looking at the field and whether one is better than the other. There was actually a really interesting presentation that came out of the ASCO GU this past year. It was a retrospective analysis that looked at patients who received pelvic plus bladder radiotherapy vs bladder radiotherapy alone. It appeared that there may be a benefit to including the pelvic field. Of course, these are early data; we have to wait for the full publication to really understand what's going on. But it was just compelling because it was probably one of the more recent evaluations looking at that question of the radiation field. Like I said, there's not one perfect regimen overall. But ideally, you'd want to think about adding on chemotherapy to improve the oncologic outcome. And of course, there's not a perfect chemotherapy, there are a lot of different options, and then other factors to consider would be the field and the dose.
This transcript was edited for clarity.