Tyler F. Stewart, MD

La Jolla, California

Disclosures:

Tyler F. Stewart, MD, is a board-certified medical oncologist who treats patients with a variety of genitourinary malignancies, including prostate, bladder, kidney and testicular cancer. He is part of UC San Diego Health's Precision Immunotherapy Clinic, which offers the most promising investigational immunotherapy treatments for many types of cancer.

Dr. Stewart is an assistant professor in the Department of Medicine at the University of California, San Diego. He trains medical students and residents. In addition, Dr. Stewart designs and runs clinical trials with novel therapeutics. His research focuses on personalizing cancer therapy based on biomarkers.

Dr. Stewart's work has been published in multiple journals, including Clinical Cancer Research and Lancet Oncology, and he has been invited to present at several national meetings. Dr. Stewart also co-authored a chapter for the 11th edition of the reference book Cancer: Principles and Practice of Oncology.

Dr. Stewart completed a fellowship in hematology and oncology at the Yale School of Medicine and the Yale Cancer Center, where he received the Yale Hematology and Oncology Annual Research Award. Dr. Stewart completed a residency in internal medicine at UT Southwestern Medical Center in Dallas. He earned his medical degree at Larner College of Medicine at the University of Vermont College, where he was inducted into the Alpha Omega Alpha (AOA) medical honor society. Dr. Stewart is board certified in medical oncology.

Talks by Tyler F. Stewart, MD

Managing the Side Effects of ADT

Posted by Tyler F. Stewart, MD | Oct 2023

Tyler F. Stewart, MD, discusses the management of the side effects of androgen deprivation therapy (ADT) in prostate cancer patients. Dr. Stewart begins by focusing on four common side effects of ADT: Fatigue, weight gain, osteoporosis, and hot flashes.
He first focuses on fatigue, a clinically relevant or severe side effect in 57 percent of patients, and weight gain. For patients who are obese at baseline, 70 percent will gain 10 or more pounds after six months of ADT.

Dr. Stewart explains that for both the fatigue and weight gain, exercise is the most important treatment, describing a randomized trial that examined resistance training and resistance and cardiovascular exercise vs. usual care. Results showed that fatigue was reduced and vitality increased with both exercise regimens.

He then turns to the risk of osteoporosis and explains that osteoporotic fractures occur in 20 percent of men by five years after starting ADT. He recommends calcium and vitamin D, bone mineral density evaluations, exercise with resistance, and consideration of osteoclast inhibitors or denosumab for patients with osteoporosis or osteopenia with a high fracture risk assessment tool (FRAX) score.

Finally, Dr. Stewart addresses hot flashes which, if they are affecting patient quality-of-life, can be treated with venlafaxine, gabapentin, oxybutynin, or medroxyprogesterone acetate. However, Dr. Stewart cautions against the use of medroxyprogesterone acetate because of the risk of cancer progression as a side effect.

Point-Counterpoint: Will Conventional Imaging Become Obsolete? – Con

Posted by Tyler F. Stewart, MD | Aug 2023

Dr. Tyler F. Stewart, MD, delivers an insightful discussion on the significant role of conventional imaging techniques in the diagnosis and treatment of this complex disease. The transformative impact of PSMA scans on precision and early detection is undeniable, offering promising prospects for improved patient prognosis.

While PSMA scans have emerged as a game-changer in various clinical scenarios, Dr. Stewart acknowledges that conventional imaging still holds value in specific contexts such as active surveillance and metastatic disease. However, he underscores the ongoing research in assessing the full potential of PSMA scans for monitoring metastatic disease, an area that continues to be explored by the scientific community.

To ensure a comprehensive evaluation and the formulation of tailored treatment strategies, Dr. Stewart emphasizes the integration of both PSMA and non-PSMA imaging techniques. By leveraging the strengths of each modality, healthcare providers can optimize diagnostic accuracy, monitor disease progression, and make informed decisions regarding the most appropriate course of action for prostate cancer patients.

This lecture is part of a Point-Counterpoint debate. Its opposing lecture is “Point-Counterpoint: Will Conventional Imaging Become Obsolete?–Pro.”

Neoadjuvant Therapy for Localized Upper Tract Urothelial Carcinoma

Posted by Tyler F. Stewart, MD | Aug 2023

Tyler F. Stewart, MD, analyzes how neoadjuvant chemotherapy options involving cisplatin or carboplatin affect upper tract urothelial carcinoma (UTUC) patients. Dr. Stewart first reviews UTUC patient outcomes, transitioning to a discussion of the POUT trial. He highlights the POUT trial’s study of cisplatin- and carboplatin-based adjuvant chemotherapies in UTUC patients following radical nephroureterectomy (RNU), noting the trial’s discovery of significant improvement in disease-free survival.

However, Dr. Stewart expresses concern with the trial’s gemcitabine-carboplatin results while emphasizing the slightly more preferable outcomes of gemcitabine-cisplatin. He sheds light on additional concerns, explaining that RNU affects cisplatin eligibility.

Dr. Stewart then discusses upstaging UTUC after RNU. He continues by evaluating the favorable results of a 2023 study involving gemcitabine and split-dose cisplatin. Dr. Stewart also analyzes other neoadjuvant chemotherapy options, including atezolizumab as studied by the ImVigor010 trial and nivolumab as studied by the CheckMate 274 trial. He pinpoints the negative results of the ImVigor010 trial, contrasting this with nivolumab’s potential as a UTUC neoadjuvant chemotherapy and FDA approval under certain conditions.

However, Dr. Stewart notes concerns with nivolumab and emphasizes the need for further study. Ultimately, Dr. Stewart highlights the benefits of perioperative cisplatin chemotherapy in comparison to carboplatin while promoting caution during the treatment of T1 patients.

Point-Counterpoint: Cystectomy vs. Trimodal Therapy for Muscle Invasive Bladder Cancer – Trimodal Therapy

Posted by Tyler F. Stewart, MD | Jul 2023

Dr. Tyler F. Stewart, MD, presents a comprehensive discussion on the topic of cystectomy versus trimodal therapy for muscle invasive bladder cancer. Highlighting the importance of a multidisciplinary approach, he emphasizes that the decision-making process involves urologists, medical oncologists, and radiation oncologists working as a team.

Dr. Stewart explores the current treatment strategies, comparing the outcomes of cystectomy and chemoradiation based on existing studies. He acknowledges the life-saving potential of cystectomies and recognizes specific scenarios where it remains the preferred option. However, he also highlights the complications associated with cystectomy, such as quality of life issues and post-surgical challenges.

Additionally, Dr. Stewart discusses trimodal therapy, which involves a combination of maximal debulking, chemoradiation, and ongoing surveillance. He addresses the lack of definitive randomized trials in this area and presents retrospective studies demonstrating comparable oncologic outcomes between trimodal therapy and cystectomy with neoadjuvant chemotherapy.

Dr. Stewart delves into the complications and late toxicities associated with trimodal therapy while discussing its potential benefits in terms of quality of life outcomes. He concludes by mentioning the exciting advancements in systemic therapies and ongoing research to improve local disease control in bladder sparing options.

This lecture is part of a Point-Counterpoint debate. Its opposing lecture is “Point-Counterpoint: Cystectomy vs. Trimodal Therapy for Muscle Invasive Bladder Cancer–Cystectomy.”

About the 30th Annual Perspectives in Urology: Point Counterpoint conference: Presented by Program Chair and Grand Rounds in Urology Editor-in-Chief E. David Crawford, MD, this conference brought together leading experts in urology, medical oncology, and radiation oncology to discuss and debate the latest topics in genitourinary cancers, primarily prostate cancer and bladder cancer. This interactive conference offered topical lectures, pro/con debates, interesting-case presentations, interactive panel discussions, and interactive audience and faculty networking.

Role of Circulating Tumor DNA and Adjuvant Therapy in Urothelial Carcinoma

Posted by Tyler F. Stewart, MD | Jun 2023

Tyler F. Stewart, MD, discusses the groundbreaking role of circulating tumor DNA (ctDNA) in adjuvant therapy for urothelial carcinoma, highlighting its potential to revolutionize cancer treatment. ctDNA, a fragmented DNA shed by cells into the bloodstream, holds immense promise in identifying minimal residual disease and predicting patient outcomes.

Dr. Stewart emphasizes the significance of ctDNA as a biomarker and its successful application in various cancer types, including colorectal and bladder cancer. He presents studies showcasing the prognostic value of ctDNA monitoring throughout the treatment course, revealing its ability to accurately predict disease recurrence. The assay DNA methodologies, such as digital PCR and targeted capture NGS, offer remarkable sensitivity and customization to individual patients.

Dr. Stewart explores the potential of ctDNA as a predictive marker for perioperative systemic therapy, which could aid in identifying patients who would benefit most from adjuvant therapy. He highlights the positive outcomes observed in ctDNA-positive patients receiving adjuvant atezolizumab, leading to improved disease-free survival and overall survival rates.

Ongoing clinical trials, such as TOMBOLA and ImVigor011, further explore the integration of ctDNA as an essential biomarker in the management of muscle invasive bladder cancer. The extensive research on ultrasensitive ctDNA assays, novel ctDNA assays, and the use of urinary biomarkers for disease monitoring adds to the growing body of evidence supporting the clinical utility of ctDNA in cancer care.

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