Introduction:

B7-H3 is overexpressed in urothelial carcinoma of the bladder (UCB) and has been shown to be a marker of response to adjuvant chemotherapy post radical cystectomy (RC). Herein, we evaluated the correlation of B7-H3 expression from transurethral resection of bladder tumor (TURBT) specimens with pathological response to neoadjuvant chemotherapy (NAC).

Methods:

Patients treated with NAC prior to RC for UCB between 2003-2021 were identified. B7-H3 expression level in the TURBT specimens was scored between 0 to 300 using H-scoring system. Expression levels of <100 were deemed “low”, and levels ³100 were assessed as “high”. The correlation between B7-H3 expression and pathologic complete response after NAC was determined using the Chi-Square test.

Results:

Forty-nine patients were included. Median age was 69 (IQR62-73) and 46 were male. All patients had ≥pT2 on TURBT. RC pathology was ypT0 in 18 patients, ypTcis in 2, ypT1 in 7, ypT2 in 4, and ypT3-4 in 18. Twenty-eight patients had low and 21 had high B7-H3 expression H-scores. Patients with low levels of B7-H3 expression had a significantly better response to NAC, defined as higher complete pathologic response rates (ypT0N0 at RC) (46.4% vs 19.1%; Hazard Ratio 0.23; p-value 0.03).

Conclusion:

Low level of B7-H3 expression on TURBT specimen is a predictor of complete pathologic response to neoadjuvant chemotherapy in UCB.

Funding: N/A