Objective  To compare clinicopathologic parameters of uncommon mutations of epidermal growth factor receptor (EGFR) and preliminary therapeutic effects of EGFR-TKI treatment in patients with non-small cell lung cancer.

  Methods  We collected clinicopathological data from 29 patients with non-small cell lung cancer who carry uncommon mutations of EGFR, which were pathologically confirmed in the Tumor Hospital Affiliated to Xinjiang Medical University, from January 2012 to April 2016. Then we analyzed the relationship between the clinicopathologic characteristics of uncommon mutations and therapeutic effects of EGFR-TKIs.

  Results  Among the 29 cases of patients with uncommon mutations, the most common distant metastasis organs were ipsilateral/contralateral lung tissue, bone, brain, liver, and adrenal gland; the most common metastatic lymph nodes were hilar lymph node, supraclavicular/subclavian lymph node, neck-root lymph node, and mediastinal lymph node. In seldom mutations, 16 cases of single mutation were found: 5 cases of L861Q, 5 cases of G719X, 4 cases of 20ins, and 2 cases of S768I. By contrast, 11 cases of double mutations were found: 4 cases of S768I and 20ins, 1 case of double mutation of L858R and S768I, 1 case of double mutation of 19Del and T790M, 2 cases of double mutations of L861Q and G719X, 1 case of 19Del and S768I, 1 case of 20ins and G719X, and 1 case of T790M and G719X. Moreover, 2 cases of triple mutation were found: 1 case of L858R, L861Q, and G719X; 1 case of S768I, 20ins, and G719X. The objective response rate (ORR) of the first-line EGFR-TKI therapy was 43.75%, the disease control rate (DCR) was 50%, and the median progression-free survival (mPFS) was 5.5 months. Furthermore, the ORR of the second-line EGFR-TKI therapy was 28.57%, the DCR was 42.85%, and the mPFS was 4 months. Moreover, the ORR of the third-line EGFR-TKI therapy was 33.33%, the DCR was 50.00%, and the mPFS was 2.67 months.

  Conclusion  Great individual differences were found on EGFR uncommon mutations for effective rate and survival time of EGFR-TKI treatment; in general, ORR and mPFS of EGFR seldom mutations were lower than classical mutations and partly higher than wild types. The first-line therapeutic effects of EGFR-TKI therapy was slightly better than the second-line or third-line therapeutic effects; however, no significant statistical difference was observed.