Assessment of the Impact of Grade Heterogeneity on Survival in Ta and T1 Tumors: A Subgroup Analysis of NMIBC Cohort.

INTRODUCTION

We aimed to compare the RFS and PFS of Ta-MG, Ta-HG, T1-MG and T1-HG groups with the hypothesis that MG tumors may have a better prognosis than pure HG tumors.

MATERIAL AND

METHODS

Patients with HG-NMIBC in the first TUR specimen between 2010 and 2020 were screened. The first TUR specimens were re-evaluated by experienced uropathologists and the percentage of LG tumor areas accompanying HG areas was determined for each case. HG tumors with accompanying LG rates ranging from 1% to 95% were evaluated as "Mixed-Grade (MG)," while tumors without any LG component (0%) were evaluated as "pure High-Grade (HG)." Survival analysis was performed using the Kaplan-Meier method. RFS and PFS were compared via the log-rank test.

RESULTS

Of the 201 patients included in the study, 25 (12.4%) had Ta-MG, 45 (22.4%) had Ta-HG, 43 (21.4%) had T1-MG and 88 (43.8%) had T1-HG tumors. The median follow-up period of the patients was 36 months. The median number of BCG instillations received by the patients was 12 and a total of 102 patients (50.7%) received a minimum of 12 doses of BCG treatment. Recurrence was observed in 6 (24%), 11 (24.4%), 13 (30.2%) and 30 (34.1%) patients in the Ta-MG, Ta-HG, T1-MG and T1-HG groups, respectively. The 36-month RFS rates were 76% (CI: 59-93), 76% (CI: 63-88), 70% (CI: 56-84) and 66% (CI: 56-76), respectively (Log-Rank; P = .701). Progression was observed in 2 (8%), 3 (6.6%), 2 (4.6%) and 19 (21.6%) patients, respectively. The 36-month PFS rates for groups were 92% (CI: 82-100), 93% (CI: 86-100), 95% (CI: 89-100) and 78% (CI: 70-87), respectively. The T1-HG group was found to have a statistically significantly lower PFS (Log-Rank; P = .016).

CONCLUSION

In BCG-treated NMIBC patients, those with T1-pure-HG tumors have worse PFS compared to those with T1-MG, Ta-HG, and Ta-MG tumors. The presence of pure-HG tumors may hold prognostic importance for NMIBC patients and might be crucial for patient classification and treatment options.