Nausea and vomiting are among the most feared side effects of cancer chemotherapy, affecting up to 40 percent of patients.

A new calculator developed by Dr. George Dranitsaris and Dr. Mark Clemons and their colleagues could help prevent this. The calculator incorporates eight risk factors to predict the likelihood that a given person will suffer from nausea and vomiting after chemotherapy. It was developed using data from nearly 1,200 patients from five studies around the world. Patients who are deemed high risk can be given more aggressive anti–nausea drugs.

A previous clinical trial led by Dr. Clemons showed that this kind of mathematical approach was more effective in preventing nausea and vomiting than leaving it up to physician choice. The calculator is meant to be used by physicians, in consultation with patients.

The findings were published in the journal Annals of Oncology.