JoEllen Zembruski-Ruple, 65, began chemotherapy for squamous cell carcinoma on January 29 at New York’s Memorial Sloan Kettering Cancer Center. She took three oral capecitabine pills—unaware that her body lacked the necessary enzyme to safely metabolize the drug.
Within days, JoEllen developed painful mouth sores and facial swelling. Her family took her to the hospital’s urgent care, where she was diagnosed with a yeast infection and sent home. Two days later, she was rushed back with severe vomiting and diarrhea. A text to a friend read simply, “Enzyme deficiency.” JoEllen was admitted and never returned home. Covered in bruises and unable to speak, she entered hospice and died on March 25.
JoEllen had a known genetic deficiency that makes the chemotherapy drug capecitabine—and its IV equivalent, 5-FU—highly toxic. Around 1,300 Americans die each year from such reactions. A simple genetic test could have revealed her risk, allowing for dosage adjustments or alternative treatments. An FDA-approved antidote exists but must be given within four days of starting treatment.
Doctors can test for this deficiency, but many don’t. The drug has been in use since 1962 and costs only about $17 per dose, so manufacturers haven’t sought testing approval. Until recently, even expert panels didn’t recommend pre-treatment screening.
JoEllen’s family said they were never told about the testing option or its life-saving importance. “If the test existed,” her sister said, “we should have been told. We would have paid for it.”
After her death, and mounting advocacy from bereaved families, national cancer guidelines have begun shifting toward recommending testing. But for JoEllen, the change came too late.
Her story underscores a critical message: patients deserve to know their risks before starting treatment that could take their life instead of saving it.
