Lack of Smoking Data in Bladder, Kidney and Prostate Cancer Clinical Trials May Affect Patient Outcomes

Clinical trials that are designed to ask patients with bladder, kidney and prostate cancer about their smoking status may help patients better understand what to expect from their treatment based on their smoking habits.

Recent study results show that data on the smoking status of patients with bladder, kidney and prostate cancer is severely lacking in clinical trials.

The concern, according to one of the study’s authors, is that trials that are not designed to collect information on the smoking status of patients are possibly providing inaccurate data on the effectiveness of treatment options for a multitude of genitourinary cancers.

Study author Calvin Zhao, a urology research associate at New York University School of Medicine, explained how this absence of data on smoking status can affect patients.

“For patients with a smoking history, this may mean potentially higher rates of adverse outcomes than what is documented in the literature, and vice-versa for non-smokers,” he said in an interview with CURE®.

The main goal of this review — which was presented at the 2021 American Urologic Association Annual Conference — was to find out if a study collected and reported data on smoking status of study participants.

In their review, Zhao and colleagues analyzed information from 354 studies of clinical trials in the genitourinary cancer space. They noted that only 30 of the studies reported on the smoking status of the patients. Moreover, 96.3% of those 30 studies reported smoking stats as “never,” “former” or “current” at the onset of the trial, instead of quantifying pack years (a measure of the amount a person has smoked over time), or intensity.

Only three of the studies included a conclusion that included information that accounted for a person’s smoking status. Of those studies, two reported significant differences in outcomes that were associated with smoking status.

None of the studies included information on non-cigarette tobacco use or changes in smoking status over time.

“Hence these trials often study treatments on an unknown mix of smokers and non-smokers, which may bias the data if smoking significantly affects outcomes. This means that patients and providers may have a suboptimal understanding of the risks and benefits when planning a treatment course,” Zhao mentioned.

“Accurate and comprehensive reporting of smoking status will enable the data from clinical trials to be better stratified by smoking intensity. Ultimately it will give patients a better understanding of what to expect from their treatment based on their specific smoking habits,” he said.

Zhao concluded that this lack of data on smoking status in clinical trials should mainly be addressed by clinicians, but he noted that patients can do their part by being forthcoming and honest when they are asked about their smoking history. Additionally, he urged current smokers to quit when diagnosed with a genitourinary cancer — such as bladder, kidney or prostate cancer — to optimize treatment outcomes, improve quality of life and minimize cancer progression.

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