Stereotactic Magnetic Resonance (MR)-Guided Radiotherapy Shows Promise for Inoperable Upper Tract Urothelial Carcinoma

Stereotactic MR-guided radiotherapy shows promise as an effective treatment for upper tract urothelial carcinoma (UTUC), particularly in patients who are not candidates for surgery, according to a case study presented in Frontiers in Oncology.

“Radiotherapy has been successfully used in treating urothelial carcinoma at other locations such as locally advanced bladder cancer in bladder preservation therapy as an alternative to radical cystectomy and oligoprogressive or oligorecurrent urothelial carcinoma, explained Wajana Thaweerat, Division of Radiation Oncology, Department of Radiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand, and coauthor. “Thus, radiotherapy could be an option for inoperable UTUC patients or palliative management that was recommended as one of the palliative treatments by the American Urological Association (AUA),” they added.

Researchers reported the case of an 87-year-old woman with UTUC at the left renal pelvis who received stereotactic body radiotherapy (SBRT) to treat hematuria. The treatment was delivered by a 1.5-T MR imaging-guided linear accelerator consisting of 35 Gy in 5 fractions.

The patient's symptoms improved following treatment, and post-treatment imaging revealed a complete response of the primary tumor. This outcome indicates that stereotactic MR-guided radiotherapy could be a viable alternative for patients who are not candidates for surgery despite radiotherapy being infrequently mentioned in current UTUC treatment guidelines.

One key advantage of this approach is the use of daily adaptive planning based on MR images obtained before treatment. This technique allows for improved target dose delivery while minimizing exposure to organs at risk. The researchers suggest that this method may decrease radiation-related adverse effects, including the potential worsening of renal function due to the tumor's proximity to the kidney.

The case study also highlights the potential of this treatment modality for both palliative and curative purposes in non-surgical candidates with UTUC. While further research is needed to fully understand the clinical benefits of adaptive planning, this case provides encouraging evidence for the use of stereotactic MR-guided radiotherapy in managing UTUC.

“Although radiation treatment still has a very limited role in UTUC at the renal pelvis, stereotactic MR-guided radiotherapy could be an interesting treatment option for nonsurgical candidates in both curative and palliative settings, as the adaptive planning allows daily reoptimization of the treatment plan after the adjustment of target and OARs, which might result in better disease control and decreased toxicity, especially renal function impairment,” concluded the study authors.

Reference

Thaweerat W, Dankulchai P. Case report: Stereotactic MR-guided adaptive radiotherapy for inoperable urothelial carcinoma at the renal pelvis. Front Oncol. 2024;13:1284417. doi:10.3389/fonc.2023.1284417