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Ashish M. Kamat

The University of Texas MD Anderson Cancer Center

ORCID: 0000-0003-3546-9928

Publishes on Bladder and Urothelial Cancer Treatments, Urinary and Genital Oncology Studies, Cancer Immunotherapy and Biomarkers. 1.1k papers and 31.1k citations.

1.1kPublications
31.1kTotal Citations

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Top publicationsby citations

Outcomes of radical nephroureterectomy: A series from the Upper Tract Urothelial Carcinoma Collaboration
Cited by 1.1kOpen Access

BACKGROUND: The literature on upper tract urothelial carcinoma (UTUC) has been limited to small, single center studies. A large series of patients treated with radical nephroureterectomy for UTUC were studied, and variables associated with poor prognosis were identified. METHODS: Data on 1363 patients treated with radical nephroureterectomy at 12 academic centers were collected. All pathologic slides were re-reviewed by genitourinary pathologists according to strict criteria. RESULTS: Pathologic review revealed renal pelvis location (64%), necrosis (21.6%), lymphovascular invasion (LVI) (24.8%), concomitant carcinoma in situ (28.7%), and high-grade disease (63.7%). A total of 590 patients (43.3%) underwent concurrent, lymphadenectomy and 135 (9.9%) were lymph node (LN) -positive. Over a mean follow-up of 51 months, 379 (28%) patients experienced disease recurrence outside of the bladder and 313 (23%) died of UTUC. The 5-year recurrence-free and cancer-specific survival probabilities (+/-SD) were 69%+/-1% and 73%+/-1%, respectively. On multivariate analysis, high tumor grade (hazards ratio [HR]: 2.0, P<.001), advancing pathologic T stage (P-for-trend<.001), LN metastases (HR: 1.8, P<.001), infiltrative growth pattern (HR: 1.5, P<.001), and LVI (HR: 1.2, P=.041) were associated with disease recurrence. Similarly, patient age (HR: 1.1, P=.001), high tumor grade (HR: 1.7, P=.001), increasing pathologic T stage (P-for-trend<.001), LN metastases (HR: 1.7, P<.001), sessile architecture (HR: 1.5, P=.002), and LVI (HR: 1.4, P=.02) were independently associated with cancer-specific survival. CONCLUSIONS: Radical nephroureterectomy provided durable local control and cancer-specific survival in patients with localized UTUC. Pathologic tumor grade, T stage, LN status, tumor architecture, and LVI were important prognostic variables associated with oncologic outcomes, which could potentially be used to select patients for adjuvant systemic therapy.

Treatment of Non-Metastatic Muscle-Invasive Bladder Cancer: AUA/ASCO/ASTRO/SUO Guideline
Sam S. Chang, Bernard H. Bochner, Roger Chou et al.|The Journal of Urology|2017
Cited by 937Open Access

PURPOSE: This multidisciplinary, evidence-based guideline for clinically non-metastatic muscle-invasive bladder cancer focuses on the evaluation, treatment and surveillance of muscle-invasive bladder cancer guided toward curative intent. MATERIALS AND METHODS: A systematic review utilizing research from the Agency for Healthcare Research and Quality as well as additional supplementation by the authors and consultant methodologists was used to develop the guideline. Evidence-based statements were based on body of evidence strengths Grade A, B or C and were designated as Strong, Moderate and Conditional Recommendations with additional statements presented in the form of Clinical Principles or Expert Opinions. RESULTS: For the first time for any type of malignancy, the American Urological Association, American Society of Clinical Oncology, American Society for Radiation Oncology and Society of Urologic Oncology have formulated an evidence-based guideline based on a risk-stratified clinical framework for the management of muscle-invasive urothelial bladder cancer. This document is designed to be used in conjunction with the associated treatment algorithm. CONCLUSIONS: The intensity and scope of care for muscle-invasive bladder cancer should focus on the patient, disease and treatment response characteristics. This guideline attempts to improve a clinician's ability to evaluate and treat each patient, but higher quality evidence in future trials will be essential to improve level of care for these patients.

CTLA-4 blockade increases IFNγ-producing CD4 <sup>+</sup> ICOS <sup>hi</sup> cells to shift the ratio of effector to regulatory T cells in cancer patients
Chrysoula I. Liakou, Ashish M. Kamat, Derek Ng Tang et al.|Proceedings of the National Academy of Sciences|2008
Cited by 535Open Access

Significant anti-tumor responses have been reported in a small subset of cancer patients treated with the immunotherapeutic agent anti-CTLA-4 antibody. All clinical trials to date, comprising over 3,000 patients, have been conducted in the metastatic disease setting, which allows for correlation of drug administration with clinical outcome but has limited analyses of intermediate biomarkers to indicate whether the drug has impacted human immune responses within the tumor microenvironment. We conducted a pre-surgical clinical trial in six patients with localized bladder cancer, which allowed for correlation of drug administration with biomarkers in both blood and tumor tissues but did not permit correlation with clinical outcome. We found that CD4 T cells from peripheral blood and tumor tissues of all treated patients had markedly increased expression of inducible costimulator (ICOS). These CD4(+)ICOS(hi) T cells produced IFN-gamma (IFNgamma) and could recognize the tumor antigen NY-ESO-1. Increase in CD4(+)ICOS(hi) cells led to an increase in the ratio of effector to regulatory T cells. To our knowledge, these are the first immunologic changes reported in both tumor tissues and peripheral blood as a result of treatment with anti-CTLA-4 antibody, and they may be used to guide dosing and scheduling of this agent to improve clinical responses.