In addition to calculating the PNIs for all 237 of the different patients that were being studied, the research team also did their best to account for other factors that could influence prognosis. The median age of the patients in the study was 50 although the range spanned from 24 to 76. Patients were also categorized as being either platinum sensitive or platinum resistant. This differentiation is important because chemotherapy treatments for ovarian cancer rely on platinum based drugs. If patients are platinum sensitive, then the drug will be more likely to have an affect; if, however, the patient is platinum resistant then the cells will likely not respond to chemotherapy. Finally, the team also classified each patient according to severity of cancer, but they noted that the majority of patients being studied were stage three.