The Prognostic Value of the Tumor Shrinkage Rate for Progression-Free Survival in Patients with Non-Small Cell Lung Cancer Receiving Gefitinib.
BACKGROUND
The efficacy of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) therapy can be measured based on the rate of treatment response, based on the Response Evaluation Criteria in Solid Tumors (RECIST) criteria or progression-free survival (PFS). However, there are some patients harboring sensitive EGFR mutations who responded poorly to EGFR-TKI therapy. In addition, there is variability in the PFS after EGFR-TKI treatment.


METHODS
We performed a retrospective analysis of the medical records of 85 patients with non-small cell lung cancer, who had achieved a stable disease or better response at the first evaluation of treatment response, after receiving a 2-month course of gefitinib. We calculated the tumor shrinkage rate (TSR) by measuring the longest and perpendicular diameter of the main mass on computed tomography before, and 2 months after, gefitinib therapy.


RESULTS
There was a significant positive correlation between the TSR and PFS (R=0.373, p=0.010). In addition, a simple linear regression analysis showed that the TSR might be an indicator for the PFS (B±standard error, 244.54±66.79; p=0.001). On univariate analysis, the sex, histologic type, smoking history and the number of prior chemotherapy regimens, were significant prognostic factors. On multivariate regression analysis, both the TSR (β=0.257, p=0.029) and adenocarcinoma (β=0.323, p=0.005) were independent prognostic factors for PFS.


CONCLUSIONS
Our results showed that the TSR might be an early prognostic indicator for PFS in patients receiving EGFR-TKI therapy.
Division of Pulmonary, Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea.
Dong Il
DI
Park
Division of Pulmonary, Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea.
Sun Young
SY
Kim
Division of Pulmonary, Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea.
Ju Ock
JO
Kim
Division of Pulmonary, Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea.
Sung Soo
SS
Jung
Division of Pulmonary, Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea.
Hee Sun
HS
Park
Division of Pulmonary, Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea.
Jae Young
JY
Moon
Division of Pulmonary, Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea.
Chae Uk
CU
Chung
Department of Radiology, Chungnam National University Hospital, Daejeon, Korea.
Song Soo
SS
Kim
Department of Preventive Medicine, Chungnam National University Hospital, Daejeon, Korea.
Jae Hee
JH
Seo
Division of Pulmonary, Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea.
Jeong Eun
JE
Lee
Carcinoma, Non-Small Cell Lung; EGFR Tyrosine Kinase Inhibitor; Gefitinib; Progression-Free Survival