Does contrast enhancement on CT suggest tumor response for chemotherapy in small cell carcinoma of the lung?
OBJECTIVE
The purpose of this article is to assess the correlation between contrast enhancement on CT and the tumor reduction ratio in small cell carcinoma of the lung after first-line chemotherapy.


METHODS
Twenty-eight patients with small cell carcinoma of lung underwent preenhancement and postenhancement CT scans before and after first-line chemotherapy, followed by second-line chemotherapy in 7 patients who had relapsed. The authors retrospectively analyzed the correlation between the tumor reduction ratio and the CT numbers of contrast enhancement in each case by multiple regression analysis using SPSS.


RESULTS
The mean tumor-reduction ratio was 58.2 +/- 43.2% after first-line chemotherapy, and the mean CT enhancement was 33.2 +/- 11.0 Hounsfield units (HU). The correlation coefficient between the tumor reduction ratio and the CT numbers of contrast enhancement was 0.57 (r = 0.32), and p value was < 0.002. After chemotherapy, more than 90% tumor reduction was seen in 11 patients. They revealed an average 41.9 +/- 7.6 HU tumor enhancement. Less than 50% tumor reduction was seen in 10 patients. They revealed an average 26.2 +/- 7.9 HU tumor enhancement. If these criteria of 30 HU contrast enhancement and 80% tumor reduction ratio were applied as a guide for chemotherapy response, the sensitivity, specificity, positive predictive value, and negative predictive value would be calculated as 85.7%, 84.6%, 85.7%, and 84.6%, respectively.


CONCLUSIONS
In small cell carcinoma of the lung, it is statistically proven that the more enhanced tumor on CT, the better response to chemotherapy. Tumor enhancement of 30 HU is a suggestive guide for chemotherapy response in patients with small cell carcinoma.
Choi
Jung-Bin
JB
Department of Radiology, Hanyang University Kuri Hospital, 249-1 Kyomoon-dong, Kuri-shi, Kyungki-do, Republic of Korea.
Park
Choong-Ki
CK
Park
Dong Woo
DW
Kim
Yongsoo
Y
Kim
Young-Sun
YS
Choi
Yo Won
YW
Jeon
Seok Chol
SC
D000368:Aged; D018288:Carcinoma, Small Cell / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D003287:Contrast Media; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D012074:Remission Induction; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media