Clinical Observation Of Pemetrexed Monotherapy Or Combination Regimen As Second-line Treatment For Advanced Non-small Cell Lung Cancer

Objective:Pemetrexed as a multi-target antifolate chemotherapeutic drug,has been widely used in the treatment of non-small cell lung cancer (NSCLC).The purpose of this study was to compare the effects and toxicities in advanced NSCLC patients treated with pemetrexed monotherapy or pemetrexed plus a platinum combination agent.Methods:The clinical data of 72 patients with NSCLC who were admitted to the First Affiliated Hospital of Dalian Medical University from August 2006 to November 2009 were retrospectively analyzed.27 of the 72 patients received pemetrexed monotherapy,and the other 45 patients received the pemetrexed plus platinum regimen.Monotherapy regimen: patients received pemetrexed 500mg/m2 on day 1,by intravenous infusion, with every 21 days.Combination regimen:patients received pemetrexed 500mg/m2 on day 1 and cisplatin 25mg/m2 on day 1-3,or carboplatin 300mg/m2 on day 1 by intravenous infusion,with 21 days as one cycle.All patients who received 2 or more cycles could be evaluated according to RECIST response evaluation criteria.Safty was evaluated according to WHO toxicity criteria.The primary end point was progression-free survival time (PFS).1-year survival rate was analyzed and the effects and toxicities were assessed.The elderly patients(≥60 years old) and pathological types were analyzed separately as subgroups.Results:There was no case with CR,11 cases had PR,34 cases had SD and 27 cases had PD.No statistically significant increase in PFS(2.8vs 3.6months,χ2=0.03,P=0.88),disease control rate(DCR)(61.1%vs75.0%,χ2=0. 75,P=0.39) or 1-year survival rate(43.0%vs38.0%,χ2=0.52,P=0.47) was found between the two regimens.The common adverse effects of the two regimens were hematologic and gastrointestinal toxicity.No gradeⅣtoxicity was found and all the toxicities were tolerable.No significant difference was found in toxicity between the two groups.In the subgroup of elderly patients,no significant difference in PFS(2.8vs3.4months,χ2= 0.13,P=0.72),DCR(χ2=0.004,P=0.95),or 1-year survival rate(χ2=0.03,P= 0.87) was found between the two regimens.The toxicity of combination therapy was significantly higher in terms of hematologic(χ2=8.48,P=0.04) and gastrointestinal adverse events(χ2=8.50,P=0.04).In the subgroup of pathological types,Pemetrexed showed the tendency of treatment advantages in non-squamous cell carcinoma in DCR(45.5%vs 70.0%,χ2=3.93,P=0.048).However,no significant difference in PFS(2.5vs 3.6months,χ2=1.74,P=0.19) was found between the two groups.1-year survival rate was 37% in non-squamous cell carcinoma and 18% in squamous cell carcinoma respectively.There was significant difference between the two groups(χ2=9.05,P=0.003).Conclusions:1. There is no significant difference in the effects and toxicities in advanced NSCLC patients treated with pemetrexed monotherapy or pemetrexed plus a platinum combination agent,especially for the elderly patients with a better safty profile.Our conclusion still supports pemetrexed monotherapy as the standard second-line regimen for NSCLC patients.2. Pemetrexed had the treatment advantages in non-squamous cell carcinoma. Non-squamous cell carcinoma was significantly higher in DCR and 1-year survival rate when compared with squamous cell carcinoma.But no significant difference in PFS was found between the two groups.