The ablative effect of mitomycin reverse thermal gel: Expanding the role for nephron preservation therapy in low grade upper tract urothelial carcinoma

PURPOSE

Assess the real-world ablative effect of mitomycin reverse thermal gel for low-grade upper tract urothelial carcinoma (UTUC) in patients who undergo biopsy only or partial ablation and evaluate utility of complete ablation prior to UGN-101.

MATERIAL AND METHODS

We retrospectively reviewed low-grade UTUC patients treated with UGN-101 from 15 high-volume centers. Patients were categorized based on initial endoscopic ablation (biopsy only, partial ablation, or complete ablation) and by size of remaining tumor (complete ablation, <1cm, 1-3cm, or >3cm) prior to UGN-101. The primary outcome was rendered disease free (RDF) rate at first post-UGN-101 ureteroscopy (URS), defined as complete response or partial response with minimal mechanical ablation to endoscopically clear the upper tract of visible disease.

RESULTS

One hundred and sixteen patients were included for analysis after excluding those with high-grade disease. At first post-UGN-101 URS, there were no differences in RDF rates between those who at initial URS (pre-UGN-101) had complete ablation (RDF 77.0%), partial ablation (RDF 55.9%) or biopsy only (RDF 66.7%) (P = 0.14). Similarly, a complimentary analysis focusing on tumor size (completely ablated, <1cm, 1-3cm or >3cm) prior to UGN-101 induction did not demonstrate significant differences in RDF rates (P = 0.17).

CONCLUSION

The results of the early real-world experience suggest that UGN-101 may play a role in initial chemo-ablative cytoreduction of larger volume low-grade tumors that may not initially appear to be amenable to renal preservation. Further studies will help to better quantify the chemo-ablative effect and to identify clinical factors for patient selection.