Author of

• 12592

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  P3.10 - Poster Session 3 - Chemotherapy (ID 210)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Medical Oncology
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/30/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 12619

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    P3.10-027 - Selection of patients with adenocarcinoma of the lung for Gefinitib by FDG PET metabolic response (ID 1628)

    09:30 - 09:30  |  Author(s): S. Chae
    • Abstract

    Background
    Gefitinib is the standard therapy for non-small cell lung cancer patients harboring activating EGFR mutation. However, there are some limitations; 1) we need sufficient tumor tissue to analyze EGFR mutation test; 2) we have to wait result of the test, causing delay of treatment; and 3) we can evaluate the response 4 weeks later but some of the patients do not respond to EGFR TKIs even though they have an activating EGFR mutation. Therefore, we investigated the role of FDG PET as a method overcoming the limitations to evaluate the response to EGFR TKIs.

    Methods
    Key eligibility is as follows; advanced/metastatic adenocarcinoma of the lung; never smoker; no prior chemotherapy; ECOG PS of 0-1; and main lesion > 2cm. The patients performed two times of FDG PET; before starting gefitinib and after 7 days of gefitinib 250mg/d therapy. If % decrease of peak standardized uptake value (pSUV) of main lesion was 20% or more, gefitinib was continued till progression (Group A). After 6 weeks of the treatment, conventional response evaluation using chest CT was done. But, if % decrease of pSUV less than 20% or increase, treatment changed from gefitinib to pemetrexed/cisplatin (Group B). Primary endpoint was to see the response rate of gefitinib in the patients of Group A. EGFR mutation test using direct sequencing method was also performed but the result was not available or unknown to investigators before the report of second PET result.

    Results
    Between Apr 2012 and Apr 2013, 50 patients participated. After 7 day-treatment of gefitinib, 28 out of 50 patients showed decrease of pSUV of main lesion ≥ 20 % (47.4±15.8%) (Group A). Out of the 28 patients in Group A, 27 patients were evaluable; PR in 24 (85.7%), SD in 2 and PD in 1 (Table). EGFR mutation was identified later in 24 patients (85.7%) and 4 patients showed wild type EGFR with 2 PRs, 1 PD and 1 NE. Twenty-two patients showed decrease of pSUV < 20 % or increase (-0.3±15.3%). Interestingly, 19 patients (86.4%) had wild type EGRF while two had an activating EGFR mutation. One patient who showed mutated EGFR in Group B was given gefitinib continuously as physician’s decision. But the patient did progressed after all.

    	Group A (gefitinib, n=28)			Group B (pem/cis, n=22)
    Response	EGFR mutation			EGFR mutation
    	Postive (n=24)	Negative (n=4)	Total (n=28)	Postive (n=2)	Negative (n=19)	NE (n=1)	Total (n=22)
    CR	-	-	0	-	-	-	0
    PR	22	2	24 (85.7%)	1	13	-	14 (63.6%)
    SD	2	-	2 (7.1%)	-	4	-	4 (18.2%)
    PD	-	1	1 (3.6%)	-	1	-	1 (4.5%)
    NE	-	1	1 (3.6%)	1	1	1	3 (13.6%)

    Conclusion
    The % decrease of pSUV of ≥ 20 % after 7 days of gefitinib treatment would be a good indicator to predict tumor response to EGFR TKI therapy in this clinical setting.