Prediction of chemotherapy response in untreated malignant lymphomas using technetium-99m methoxyisobutylisonitrile scan: comparison with P-glycoprotein expression and other prognostic factors. A preliminary peport.

BACKGROUND

The purpose of this study was to predict chemotherapy response in untreated malignant lymphomas using technetium-99m methoxyisobutylisonitrile (Tc-MIBI) scan.

METHODS

Twenty-five patients with malignant lymphoma were studied before receiving chemotherapy. Early Tc-MIBI scan was performed 10 min after intravenous injection of Tc-MIBI. Immunohistochemical analyses were performed on multiple non-consecutive sections of the biopsy specimens to determine Pgp expression. Chemotherapy response was evaluated in the first 1-2 years after completion of treatment by clinical and radiological methods.

RESULTS

The mean tumor-to-background ratio of the 15 patients with good response (3.3 +/- 0.6) was significantly higher than that of the 10 patients with poor response (1.2 +/- 0.1). Among the 15 patients with good response to chemotherapy, all had positive Tc-MIBI scan results but negative Pgp expression. Among the 10 patients who had poor response to chemotherapy, all 10 had negative Tc-MIBI scan, but six patients had positive Pgp expression and four had negative Pgp expression. Significant differences were found in the incidences of good and poor responses determined by Tc-MIBI scan and Pgp expression. However, there were no significant differences in the incidences of good and poor responses for other prognostic factors.

CONCLUSION

Compared with other prognostic factors, early Tc-MIBI scan more accurately predicts chemotherapy response in patients with malignant lymphoma.