Grouping specific types of lymphoma into three categories low-grade, intermediate-grade, or high-grade categories correlates highly with the expected survival of patients with these diseases who are not undergoing treatment. Without treatment, patients with low grade lymphomas typically survive several years. On the other hand, patients with intermediate or high grade lymphomas who do not receive treatment rarely survive more than several months. Although patients with low grade lymphomas, on average, survive longer than those with intermediate or high grade lymphomas, they are unlikely to be truly cured by standard chemotherapy treatment.

Patients with low grade lymphoma may have a response to treatment lasting several years. However, after a remission of several years, relapse of their lymphoma is not unusual. Although intermediate and high grade lymphomas are inherently more dangerous, they are more likely to respond initially to radiation therapy and especially to chemotherapy. This is because these treatments are most effective in killing cancer cells that are rapidly dividing. Patients with intermediate and high grade lymphomas who have responded well to treatment and have had a complete remission of several years' duration are less likely to have late recurrences.