Potentially inappropriate medications, drug interactions common in geriatric cancer



Geriatric adults with cancer often have multiple co-morbidities and are therefore often prescribed multiple medications. A study published in the Journal of Geriatric Oncology examined the prevalence of potentially inappropriate medications (PIM), serious drug interactions (SDI) and their associated risk factors in the elderly.

The aging of the population has led to an increase in cancer rates, which is often one of the many complex diseases treated simultaneously in this population. Therefore, it is increasingly important for oncologists to consider several factors when treating cancer, including:

  • The Evidence Base for Treatment of the Elderly
  • The potential of cancer treatments to interact with other co-morbidities, medications, and the functional and cognitive status of patients
  • The relevance of treating cancer in the context of other conditions

Polypharmacy, defined as 6 or more drugs, is said to be as common in older people without cancer as in those with cancer. Pitfalls like potentially inappropriate prescriptions and adverse drug reactions can lead to increased use of healthcare resources. In this study, researchers also identified rates of major polypharmacy, defined as 11 or more drugs.

The study took place over 1 year in 2 large hospitals serving around 800,000 in the Republic of Ireland. The Seniors Prescription Screening Tool (STOPP) and OncPal Criteria were used to identify SIDs. The STOPP criteria include drugs prescribed without an evidence-based clinical indication and any drug prescribed beyond the recommended duration. OncPal is a deprescribing tool designed to identify and assist deprescribing in cancer patients with limited life expectancies. Stockley’s Interaction Checker identified potential SDIs.

The 12-month observational study aimed to identify PIDs in cancer patients 65 years of age and older. It was part of a larger prospective observational study evaluating the prevalence, predictability and prevention of adverse reactions in cancer treatment in general. A total of 186 patients with a mean age of 72 years were included.

The mean number of comorbidities was 7.5 and multimorbidity (more than 2 chronic diseases) was identified in 100% of patients. A total of 79% of patients had 5 or more chronic conditions. The most common cancer diagnoses were of the lung (23.1%), breast (11.8%) and colorectal (11.3%). The most common non-cancerous diagnoses were anemia (68.3%), hypertension (57%) and dyslipidemia (50.5%)

A total of 1283 drugs were prescribed to 178 participants, or 95.7% of the entire group. The median number of drugs prescribed per patient was 7. Polypharmacy and major polypharmacy were identified in 113 (60.8%) and 33 (17.7%) patients, respectively. Of 186 patients, 60.2% (112) were prescribed systemic cancer therapy (SACT). A total of 42 (22.6%) were receiving concomitant radiotherapy. Prescriptions other than cancer most often included proton pump inhibitors (58.6%), statins (40.3%), beta blockers (33.3%), opioids (30.6%) and antiplatelet drugs (28%).

Regarding the STOPP criteria, 136 participants (73.1%) were prescribed at least 1 PIM. The median was 2, with a range of 0 to 7. Patients who received more than 1 PIM had significantly more comorbidities. For each additional prescription, the odds of receiving a STOPP PIM increased by 79.2%.

The researchers reported that 81.8% of patients had received at least 1 PIM, according to the OncPal criteria. With each additional prescription, the odds of being prescribed an OncPal PIM increased by 38.2%. The authors noted that despite 41.4% of patients who died within 6 months of inclusion, 81.8% of patients had received at least 1 OncPal PIM. “Many of the drugs listed in this tool are preventative treatments, and prescribing them in the last few months of life is unlikely to be of benefit and may present an increased iatrogenic risk,” they wrote.

Of the 186 participants, 50.5% (94) had at least 1 potential SDI. This included 7.5% with SACT-SACT SDI potential, 10.2% with SACT-other drug SDI potential, and 41.4% with at least 1 SDI drug-drug potential. These patients with potential SDI were more likely to have more chronic illnesses and to be prescribed more medications. These patients were also more likely to have died within 6 months of enrollment, and the odds of a potential SDI increased by 50.8% with each additional medication.

A limitation of the study was that only one physician performed the PIM assessment, although the physician was a senior geriatrician with a particular interest in geriatric drug therapy.

The authors concluded that in elderly cancer patients, high rates of multimorbidity, PID, and SDI are common. A specialist assessment by a geriatrician can help identify PID before any side effects occur.

“Older people with cancer may benefit from a comprehensive medication review by a specialist geriatrician with expertise in clinical pharmacology (including in-depth knowledge of chemotherapeutic agents), experience in managing multimorbidity and a clear understanding of cancerous disease in this population, ”the authors concluded. “… Structured drug reviews in elderly multimorbid cancer patients are an important part of the optimal treatment of these patients. “


Lavan A, O’Mahoney D, O’Mahony D, Gallagher P. Potentially inappropriate drug use (PIM) and serious drug interactions (SDI) in older people with cancer. J Geriatr Onc. Published online February 26, 2021. doi: 10.1016 / j.jgo.2021.02.021



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