“Concomitant medication use, including agents that prolong the corrected QT (QTc) interval, can result in the exclusion of patients with cancer from clinical trials,” the researchers posited. “To estimate the potential effects on accrual, we determined the prevalence of QTc-prolonging medication prescriptions in a national patient cohort.”
The Veterans Affairs system was queried for adults diagnosed with lung cancer between 2003 and 2016. The use of QTc interval-prolonging medications and risk category were determined using CredibleMeds.
Final analysis included 280,068 patients (mean age, 70 years), of whom 98% were male and 72% were white. Just over a quarter of patients (28.4%) received a prescription for a QTc-prolonging medication; 7.3% were prescribed two or more QTc-prolonging medications during the three-month period prior to their cancer diagnosis. The majority of QTc-prolonging medications prescribed were antimicrobial agents (14.0%), psychiatric agents (10.2%), antiemetic agents (2.6%), and cardiac medications (1.7%). Not including antimicrobial agents, 18.4% of patients received a prescription for a QTc-prolonging medication.
“This issue comes up all the time in my practice,” study author David Gerber, MD, said in a press release. Dr. Gerber is a professor of internal medicine and population and data sciences and treats lung cancer patients at UT Southwestern Medical Center in Dallas. He has a decade of experience studying clinical trial eligibility criteria.
“The criteria are not as thoughtful as they could be,” said Dr. Gerber. “We keep cutting and pasting from earlier studies, basically doing the same things over and over without justifying them or deciding if they’re rational.”
Given the severity of lung cancer, clinical trials are important. According to Dr. Gerber, “When we design clinical trials, we need to consider potential benefits as well as theoretical risks.”
In their paper the study authors concluded, “A substantial proportion of individuals with lung cancer will be prescribed QTc-prolonging medications. These prescriptions can limit patients’ eligibility for clinical trials and complicate the administration of standard cancer therapies. Further research into the actual clinical risks and optimal management of QTc-prolonging medications in cancer populations is warranted.”