Non-Hodgkin's lymphoma in Saskatchewan. A review of 10 years' experience.

BACKGROUND

The incidence and treatment of non-Hodgkin's lymphoma (NHL) have changed in recent years. This study was intended to compare current features with a previous study (1966-1975) and assess the impact of these changes in our jurisdiction.

METHODS

Clinical features and treatment of 547 patients with NHL registered at our center from January 1980 through December 1989 were reviewed, including reassessment of histologic type in each patient. Multivariate analysis of potential pretreatment prognostic factors was performed using the Cox proportional hazards model, and survival was analyzed in relation to treatment outcome.

RESULTS

This review includes virtually all incident cases of NHL in a defined geographic area, representing an average annual incidence of 11.3/100,000 population. The male-to-female ratio was 1.1:1, median age was 65 years (range, 4-92 years). Median survival time (MST) of 482 patients with disease diagnosed antemortem was 4.8 years (95% confidence interval [CI], 3.7-6.1 years), 52% of whom have died. Thirty-nine percent of patients with disease classified by the International Working Formulation (IWF) had low-grade disease (MST, 103 months); 27% had intermediate disease (MST, 62 months), and 30% had high-grade disease (MST, 35 months). Sixteen percent of patients had associated neoplasms: 4 acute leukemias, 35 skin cancers, and 37 miscellaneous solid tumors. Results of radiation therapy (RT), chemotherapy (CT), and combined CT/RT were analyzed. Survival correlated strongly with responsiveness to treatment. Considering all patients treated with CT, anthracycline-containing CT was associated with the highest response rate, and survival time (more than 48 months) may have been affected by the addition of this agent. A survival advantage for patients with bulky Stage I and II disease treated with consolidative RT after CT is suggested, but not for more advanced stage disease. The proportional hazards model identified histologic type, disease stage, patient age, hemoglobin level, lactate dehydrogenase (LDH) level, bulky abdominal disease, and systemic "B" symptoms as significant independent prognostic factors influencing survival.

CONCLUSIONS

The incidence of NHL has increased, and the survival of patients with high-grade disease has improved significantly since the previous study. A high incidence of other associated malignancies was demonstrated in this group of patients with NHL. Recognition of prognostic factors should permit a rational application of innovative treatments for patients in unfavorable prognostic categories.