From Marc Ladanyi and colleagues: Response to Erlotinib in Patients with EGFR Mutant Advanced Non-Small Cell Lung Cancers with a Squamous or Squamous-like Component

http://www.ncbi.nlm.nih.gov/pubmed/22896669

Mol Cancer Ther. 2012 Aug 14. [Epub ahead of print]

Response to Erlotinib in Patients with EGFR Mutant Advanced Non-Small Cell Lung Cancers with a Squamous or Squamous-like Component.

Paik PK, Varghese AM, Sima CS, Moreira AL, Ladanyi M, Kris MG, Rekhtman N.

Source

1Medicine, Memorial Sloan-Kettering Cancer Center.

Abstract

We previously showed that while EGFR mutations are not a feature of pure squamous cell carcinomas of lung (SQC), these mutations do occur in adenosquamous carcinomas (AD-SQC) and in rare solid adenocarcinomas (ADC), both of which can mimic SQC in small samples. Here we present an expanded series of these cases with a focus on sensitivity to erlotinib. The study included 13 patients with EGFR mutant lung carcinomas, which after detailed pathologic review were classified as AD-SQC (n=11) or solid ADC (n=2). The majority received a diagnosis of "SQC" in at least one sample. All patients were treated with erlotinib. 8 of 11 patients with AD-SQC were evaluable for response. Their overall response rate was 88% (7/8; 95% CI: 47%-99%). One of 2 solid ADC patients responded to erlotinib. As a group, median PFS was 12 months (95% CI: 8-NR); median OS was 29 months (95% CI: 27-NR). In conclusion, EGFR mutant AD-SQC and solid ADC show a response to erlotinib that is comparable to that seen in patients with conventional ADC. These tumors can mimic SQC in small samples. We propose an approach to increase the capture of these rare histology patients for EGFR mutation testing.