Clinical pretreatment risk factors and Ga-67 scintigraphy early during treatment for prediction of outcome of patients with aggressive non-Hodgkin lymphoma

Background: Clinical pretreatment risk factors indicate the severity of disease in patients with aggressive non-Hodgkin lymphoma (NHL). Ga-67 scintigraphy during treatment is an early indicator of treatment-related features of lymphoma cells. The ability of risk factors and Ga-67 to predict disease outcome was compared in 139 patients with aggressive NHL.

Methods: Pretreatment clinical risk factors and Ga-67 scintigraphy performed after one cycle and at mid-treatment were evaluated for their correlation with response rate and as predictors of 5-year failure-free survival (FFS). Univariate analysis was performed to determine the ability of pretreatment risk factors and Ga-67 early during treatment to predict FFS. Subsequently, multivariate analysis was performed on the variables with significant univariate results using the Cox proportional hazards method. The predictive value of risk factors and Ga-67 scintigraphy was calculated to determine their suitability in selecting patients with poor outcome.

Results: Response rate correlated with stage of disease (P < 0.01) and the international prognostic index (IPI) score (P < 0.05). Five-year FFS was predicted by stage of disease (P < 0.004), performance status (P < 0.02), and the IPI score (P < 0.01). Response rate correlated with results of Ga-67 scintigraphy after one cycle of chemotherapy (P < 0.001) and at mid-treatment (P < 0.001). Five-year FFS was predicted by Ga-67 after one cycle of chemotherapy (P < 0.0004) and at mid-treatment (P < 0.0001). Positive Ga-67 after the first cycle of treatment predicted 64% of patients who had failure of treatment. A positive study at mid-treatment predicted 77% of patients who had treatment failure. Cox analysis showed Ga-67 after one course (P < 0.0012) and at mid-treatment (P < 0.0002) as being the most significant variables in predicting FFS.

Conclusions: Ga-67 scintigraphy demonstrates early the effect of treatment in patients with aggressive NHL. It is a better predictor than pretreatment risk factors of both response rate and FFS. Positive Ga-67 early during treatment may be used as an independent test in selecting patients who will not respond favorably to current protocol treatment for early therapeutic modifications.