A population-based study of severity of comorbidity among patients with non-Hodgkin's lymphoma: prognostic impact independent of International Prognostic Index

Over 60% of patients aged over 70 years, diagnosed with non-Hodgkin's lymphoma (NHL) in the Netherlands have serious comorbidity. We studied the independent influence of comorbidity on choice of treatment, dose reductions, treatment-related toxicity and prognosis, using data from a random sample of 381 patients from the population-based Eindhoven Cancer Registry. About 45% of patients over 60 years of age with NHL had high impact comorbidity at the time of cancer diagnosis. The proportion of patients with aggressive NHL who received chemotherapy decreased from 85% in patients aged 40-60 years to 70% in those over 60 years. About 65% of systematically treated patients with aggressive NHL suffered from treatment-related toxicity. Toxicity appeared to be more common among females and those with high-intermediate or high International Prognostic Index (IPI) risk. Among patients with aggressive NHL, the chance of dying for those with high impact comorbidity was twice as high compared with those without comorbidity. This was independent of the IPI risk. Dose reductions are frequently unavoidable for patients with severe comorbidity, poor performance status or chemotherapy-related toxicity. Whether the less frequent prescription of (full dose) chemotherapy for patients with advanced age and/or with comorbidity is justified remains a question for debate.