After gefitinib was approved in July 2002, we experience long-term surviving patients in the actual clinical setting. However, it is not clear how the factors or treatment strategy are contributing to the long-term surviving patients. We evaluated the effects of clinical backgrounds and treatment histories on overall survival (OS).Methods
We extracted information on advanced NSCLC patients with the following inclusion criteria from the medical records: (i) patients who were diagnosed by October 2010 and treated with gefitinib after July 2002; (ii) performance status (PS) 0–2, (iii) PR, CR or long SD (6 months or more) by gefitinib treatment; (iv) patients who had not received curative surgical operation or curative radiation therapy. Primary objective is to evaluate the survival time of the patients who responded to gefitinib and clarify the relationship between clinical factors and survival time. We also conducted ‘Dynamic Treatment Regimen Analysis (DTRA)’ to explore the key treatment regimen and the sequence of regimens contributing to long-term survival.Results
The medical records of total of 275 patients were extracted; 44% (122/275) were EGFR mutation examined and 93% (114/122) has shown the EGFR mutation positive. The mean age was 65, 72% (198/275) were women, 66% (182/275) were non-smokers and 90% (247/275) had adenocarcinoma histology. 20% (54/275) and 21% (58/275) underwent re-administration and beyond PD administration of gefitinib, respectively. The median survival time (MST) was 615 days (95% CI: 519–691). 10% patients survived for more than 5 years. The multivariate Cox analysis demonstrated that sex (P = 0.0108) and gefitinib re-administration (P = 0.0012) were significant independent factors for long-term OS. Grade 3/4 interstitial lung disease, skin, diarrhea and liver dysfunction were observed in 1.5, 4.4, 1.1 and 13.1% of the patients, respectively.Conclusions
This study suggests that sex and gefitinib re-administration may have significant affects on OS in long survivors after responding gefitinib treatment.