[A comparative study of HRCT and pathological subtype, EGFR gene mutations of peripheral small lung adenocarcinoma]

To investigate the relationship of the preoperative HRCT, postoperative pathological subtype and EGFR gene mutation types in the patients of small peripheral lung adenocacinoma confirmed by operation.

Between December 2011 and November 2014, Ninety-four invasive adenocarcinoma patient were selected from 156 patients with pulmonary nodule underwent operation in Beijing Chaoyang hospital. Among them, there were male 37 cases, female 57 cases, age range from 32 to 76, mean age 52.6. All patients underwent complete anatomical lobectomy or wedge resection or segmentectomy, with systematic mediastinal lymph node dissection. The detection indexes included: preoperative HRCT, postoperative pathological subtypes, lymph node; EGFR, Kras, ALK, FGF9 gene expression and so on.

Postoperative pathologic acinar predominant accounted for 33.0% (31/94), papillary predominant type accounted for 25.5% (24/94), Lepidic predominant adenocarcinoma accounted for 19.1% (18/94), 13.8%(13/94) micro papillary predominant, 8.5% (8/94) solid predominant. 7 patients with lymph node positive included 5 cases of stations 11-12, 1 case of station 4 and 1 case of station 7. 36 cases was detected EGFR mutation after operation (38.9%, 36/94), mainly 19⁺ and 21⁺. Compared with the preoperative HRCT findings, there was no significant difference in EGFR mutation group and non mutation group (χ² = 1.411, P=0.703). For different types of mutations in EGFR gene, there was no statistical difference (P>0.05). But the rate of EGFR 21 positive in progression patients was significantly higher than that of EGFR 19 positive patients(χ² = 5.779, P=0.016).

There were no significant different between the HRCT manifestations and pathological subtypes in the rate of EGFR gene mutation. EGFR 21 gene mutation was found in double lung metastasis commonly.