Erlotinib has demonstrated survival benefit in patients with not only adenocarcinoma but also squamous cell carcinoma. Epidermal growth factor receptor-tyrosine kinase inhibitors are more effective in Asian populations, including the Japanese than in western populations. However, a higher incidence of interstitial lung disease has been reported as a fatal adverse event in the Japanese population. There is little data on erlotinib for Japanese patients with pretreated squamous cell carcinoma.Methods
Between January 2004 and October 2010, we retrospectively evaluated the efficacy and toxicity of erlotinib administered as the first epidermal growth factor receptor-tyrosine kinase inhibitors for 41 Japanese patients with pretreated squamous cell carcinoma. Patients with pre-existing interstitial lung disease were carefully excluded by several examinations including high-resolution computed tomography.Results
The response rate and disease control rate were 9.7% [95% confidence interval: 2.7–23.1%) and 43.9% (95% confidence interval: 28.5–60.2%], respectively. Median time to treatment failure and overall survival were 2.2 months (95% confidence interval: 1.0–2.8 months) and 11.0 months (95% confidence interval: 5.7–15.7 months), respectively. Interstitial lung disease (Grade 5) was observed in one (2.4%) patient. Patients with Grade 0–1 skin rashes vs. patients with Grades 2–3 exhibited disease control rates of 28 vs. 83% (P = 0.0017), and median time to treatment failure of 1.2 months vs. 3.4 months (P = 0.0099).Conclusions
Erlotinib has moderate efficacy for pretreated squamous cell carcinoma in Japanese patients. A higher grade of skin rash was associated with clinical benefit. Careful exclusion of pre-existing interstitial lung disease can minimize the occurrence of interstitial lung disease.