GU Oncology Now recently spoke with Dr. Omar Alhalabi, Assistant Professor of GU Medical Oncology at the University of Texas MD Anderson Cancer Center. We discussed a that was involved in that was presented at this year’s ASCO meeting titled: “Survival outcomes in patients receiving immune checkpoint inhibitor for metastatic small cell urothelial cancer”.
GU Oncology Now: Can you provide us with some background on yourself?
Dr. Omar Alhalabi: Yes, my name is Omar Alhalabi and I’m an Assistant Professor of GU Medical Oncology at the University of Texas MD Anderson Cancer Center. My primary interest is in bladder cancer, as well as other genitourinary malignancies.
What prompted you to conduct this study?
Yes. Will be happy to. So, the reason we conducted this study is, as it maybe well-known to the audience, small cellular urothelial cancer represents rarer variant of urothelial cancer representing around 1% of the whole urothelial cancer population. What it is usually linked to a more aggressive behavior with 90% of patients presenting with invasive disease. Our group at MD Anderson had previously analyzed the outcomes of these patients and had shown that neoadjuvant chemotherapy compared to cystectomy alone showed improvement in these patients’ survival. Following paper, looking at the different regimens for initial therapy for these patients and we had our Dr. Arlene Siefker-Radtke had presented and published data about the regimen of cisplatin/etoposide alternating with ifosfamide/Adriamycin.
In this effort, we, in addition to these chemotherapeutic regimens, wanted to investigate the impact that the approval of immunotherapeutic agents for urothelial cancer had on these patients and their survival outcomes and how do they compare to the previous era of only chemotherapeutic agents.
What were the findings of this study, and were they surprising?
Yeah, definitely. So, the study was a historic retrospective study in nature. We basically retrieved the patients with urothelial cancer and specifically with the small cell variant in their histology using an IRB approved protocol and analyze the patients that had metastatic disease. So, out of a large cohort of urothelial cancer with small cell histology which was 275 patients, we ended up with 102 that had metastatic disease. And then we basically classify the patients that never received immunotherapy as part of their management, which was 63 of these patients versus 39 patients that received immunotherapy as part of their management at course, either front-line or second-line treatment and compared the survival outcomes between the two cohorts.
The main result that we found is that patients who had received immunotherapy as part of their management had an improved or a better median overall survival as compared to the ones that never received immunotherapy. With a median overall survival among the recipients of immunotherapy of around 20 months versus 12 months in the ones that received chemotherapy alone. With a hazard ratio of 0.45 and a p-value of 0.003. Now, this result was a little bit surprising. From our experience with the small cell variant of prostate cancer, for example, we don’t see such complete clinical benefits to immunotherapy where this area is still an investigation. But in urothelial cancer, we did see this positive impact of survival.
Now, this is obviously limited by the fact that this is a retrospective and historic type of study. And possibly, this improved outcome might be due to these patients being treated at later years compared to previous years when the standard management, overall, improved and the way we deliver care and ancillary services in oncology had improved and that could have contributed to the improved survival in these patients. But, despite the limitation, this study, although this is a rare variant and it’s difficult to conduct clinical trials in this type of disease, we believe that further prospective studies are indicated to help confirm this finding.
What are the key takeaways of this study?
So, we, in this study, are planning to do further analysis in terms of the characteristics of the patients that had achieved clinical benefit to immunotherapy, whether in regards to their response to therapy or whether it has to do with their survival and so that analysis is yet to come. But the major takeaway is, it does seem that immuno-checkpoint inhibitor therapy was associated with improved overall survival for patients with metastatic small cell urothelial cancer. And as I mentioned, it does warrant further investigation in the future.