[Recurrence of non-small cell lung cancer after successful treatment with gefitinib--report of three cases].

Gefitinib, a first epidermal growth factor receptor (EGFR) inhibitor has been reported to be effective in chemotherapy-resistant non-small cell lung cancer. Gefitinib was also reported, however, to produce severe adverse effects, such as interstitial lung disease. Thus, clinical evaluation of gefitinib is still controversial and further studies are needed. We present 3 cases of non-small cell lung cancer (stage IV adeno-carcinoma) that showed recurrence after successful gefitinib treatment. Symptoms of all patients ameliorated in a week after the therapy, and radiograph and laboratory data improved. However, all showed recurrence in 3 to 7 months. After recurrence, patient 1 was re-treated with gefitinib at the request of the patient. Patient 2 has been on gefitinib. Patient 3 was treated with gefitinib, which was later replaced by another chemotherapy agent. After recurrence, however, no effective response was obtained in any of the 3 cases. There have been several reports of good response to gefitinib therapy at the first time in patients with advanced non-small cell lung cancer, but few reports of recurrence in patients after successful therapy with this agent. This report is thought to be important for the clinical evaluation of gefitinib and useful in terms of information about the resistance of gefitinib.