Association of positive Ki-67 and PD-L1 expressions in post neoadjvuant chemotherapy (NAC) radical cystectomy samples with lack of tumor downstaging (TD) and shorter overall survival (OS) in patients with muscle-invasive bladder cancer (MIBC).

Authors

null

Selene Rubino

University of South Florida, Morsani College of Medicine, Tampa, FL

Selene Rubino , Wade J. Sexton , Youngchul Kim , Junmin Zhou , Jasreman Dhilon , Philippe E. Spiess , Michael Adam Poch , Brandon J Manley , Roger Li , Julio M. Pow-Sang , Scott Michael Gilbert , Jingsong Zhang

Organizations

University of South Florida, Morsani College of Medicine, Tampa, FL, Department of Genitourinary Oncology, Moffitt Cancer Center, Tampa, FL, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, H Lee Moffitt Cancer Center, Tampa, FL, Moffitt Cancer Center, Tampa, FL, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL, H. Lee Moffitt Cancer Canter and Research Institute, Tampa, FL

Research Funding

No funding received
None.

Background: Previous chart review studies have reported that adjuvant chemotherapy after NAC did not clearly increase OS in MIBC cases characterized by a lack of TD. There is an unmet need to develop biomarkers to guide adjuvant therapy for this patient population. High levels of expression of cell proliferation marker Ki-67 are associated with poor outcome in chemotherapy naïve bladder cancer. Expression of PD-L1 has been studied as a potential predictive biomarker for anti-PD1 or PD-L1 therapies in metastatic MIBC. We therefore studied Ki-67 and PD-L1 expression in post NAC radical cystectomy samples at Moffitt Cancer Center and correlate them with TD and OS. Methods: Tissue microarrays (TMAs) were constructed from 116 post NAC cystectomy samples. The expressions of Ki-67 were evaluated with immunohistochemistry (IHC) and considered positive if any of the cores per sample were stained positive for Ki-67. The Dako 22C3 assay was used for PD-L1 IHC and the combined positive score of 10 or above was considered positive for PD-L1. Results: The median survival of this cohort of 116 patients was 33.4 months (range: 1.13 -127 months). 40 patients (35%) had TD and 21 patients (18%) achieved pathological complete response. Using Cox regression for OS, positive Ki-67 expression in post NAC radical cystectomy sample was associated with poorer OS (hazard ratio=2.412, 95% CI:1.076-5.408, p=0.033), independent of the pathological N stage. Patients with Ki67/PD-L1 double-negative tumors had a significantly longer median OS of 98.2 months versus 29.9 and 26.9 months in PD-L1-/Ki67+ and PD-L1+/Ki67+ tumors respectively (Log-rank test, p=0.0361). Lack of TD was significantly associated with positive Ki-67 (P<0.001) and positive PD-L1 (p=0.003) in the post NAC samples with a multi-variable logistic regression model. Conclusions: Positive Ki-67 and PD-L1 expressions in post NAC radical cystectomy samples were associated with inferior OS and absence of TD. Adjuvant anti-PD1 therapy either alone or in combination with chemotherapy would be indicated for this subset of patients.

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Abstract Details

Meeting

2020 Genitourinary Cancers Symposium

Session Type

Poster Session

Session Title

Poster Session B: Prostate Cancer; Urothelial Carcinoma; Penile, Urethral, Testicular, and Adrenal Cancers

Track

Urothelial Carcinoma,Adrenal Cancer,Penile Cancer,Prostate Cancer - Advanced,Prostate Cancer - Localized,Testicular Cancer,Urethral Cancer

Sub Track

Tumor Biology, Biomarkers, and Pathology

Citation

J Clin Oncol 38, 2020 (suppl 6; abstr 554)

Abstract #

554

Poster Bd #

L13

Abstract Disclosures

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