How can clinicians other than the oncologist be more informed about the drugs they prescribe? Some drugs can cause cancer, and the clinician does not appear to consider that when prescribing for a patient with cancer. —Name withheld on request
All prescription medications have prescribing recommendations or references that clinicians can access. Within the prescribing references, or what is called the “Prescribing Information (PI),” pharmaceutical companies list indications and use, dosage and administration, contraindications, warnings and precautions, adverse reactions, drug interactions, use in specific populations, overdosage, clinical pharmacology, nonclinical toxicology and clinical studies, how medication is supplied, and patient counseling information. The nonclinical components of this information often address the carcinogenic potential of the medication.
All clinicians have access to this information when prescribing oral and intravenous oncolytics. For example, the prescribing information for erlotinib (Tarceva) states that carcinogenicity studies were conducted for 2 years with no identified carcinogenic risks discovered at variable dosages of the medication; however, temazolamide (Temodar) was found to be carcinogenic in rats inducing mammary cancers in both males and females at doses 0.13 to 0.63 times the maximum human dose (25-125 mg/m2) when administered orally on 5 consecutive days every 28 days for 6 cycles. Therefore, prescribing clinicians have the necessary information to make them aware of the potential carcinogenic effects of the medications they prescribe to treat malignancies.
The risk-benefit ratio should be weighted when treatment decisions are being determined, and patients legally have to be made aware of these risks when signing informed consent for treatment. It is the responsibility of the prescribing clinician to know the risk of secondary malignancies when prescribing medications and the incidence of such risks, and the overall benefit to the client of the medication being prescribed. —Jiajoyce R. Conway, DNP,FNP-BC, AOCNP