Purpose: In this study, the authors wanted to determine whether dipyridamol
e-modulated MIBI (dipyridamole-MIBI) could enhance the prediction of the re
sponse to chemotherapy in patients with small cell lung cancer.
Methods: Twenty-seven patients with biopsy-proved small cell lung cancer (2
5 men, 2 women; mean age, 61+/-7 years) underwent dipyridamole-MIBI SPECT 3
to 7 days before starting chemotherapy (80 mg/m(2) etoposide and 80 mg/m(2
) cisplatin every 3 or 4 weeks for at least two cycles), Tomographic images
before and after dipyridamole (0.84 mg/kg) were acquired 1 hour after inje
ction of 370 (10 mCi) and 1,110 (30 mCi) MBq MIBI, respectively, The respon
se to chemotherapy was grouped as specified as complete response (CR), part
ial (PR), no change (NC), or progressive disease (PD), according to the cha
nge in tumor size on chest roentgenography and CT. Patients showing CR and
PR were classified as responders, and those who showed NC and PD were consi
dered nonresponders.
Results: Among the 27 patients, 22 were responders (3 CR, 19 PR) and 5 were
nonresponders (3 NC, 2 PD), The tumor-to-normal lung ratio (T:NL) of respo
nders was significantly higher than that of nonresponders. The diagnostic a
ccuracy of the T:NL ratio to differentiate responders and nonresponders was
33.3%, with a cutoff value of 2.5, which was significantly improved to 77.
8% when an increased T:NL ratio after dipyridamole was assigned to a nonres
ponder. Furthermore, all patients with CR showed diminished T:NL ratios aft
er dipyridamole, and all patients with NR showed an increased T:NL ratio af
ter dipyridamole,
Conclusion: Dipyridamole-MIBI SPECT could enhance the prediction of respons
e to chemotherapy in patients with small cell lung cancer.