Radiotherapy With Continued EGFR-TKIs for Oligoprogressive Disease in Non–Small Cell Lung Cancer: A Real-World Study

Almost all epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) will develop tyrosine kinase inhibitors (TKIs) resistance. The treatment of oligoprogression is debatable after TKIs resistance. We conducted a real-world retrospective study to evaluate the efficacy of radiotherapy and continuation of TKIs in advanced NSCLC patients with oligoprogressive disease after EGFR-TKIs. Methods: From January 2011 to January 2018, we retrospectively analyzed EGFR-mutated NSCLC patients with oligoprogression in our institution. 33 patients were treated by radiotherapy and continuation of TKIs. We used Kaplan-Meier and Cox regression model to analyze the prognostic factors of progression-free survival (PFS) and overall survival (OS) from the time of oligoprogression. Variables we selected for analyses included gender, age, smoking status, performance status (PS) score, stage at initial diagnosis, initial resectable, radiotherapy dose, EGFR mutation type, number of metastasis, sites of radiation, T790M status, time of oligometastasis to radiotherapy. Results: 33 patients develop resistance to EGFR TKIs at a median time of 11.0 months. The mPFS and mOS were 6.5 and 21.0 months, respectively. T790M mutation was tested in 8 patients. The mPFS was 11.3 months in T790M mutation positive patients and 6.0 months in negative patients. The mPFS of patients with brain, lung, and bone metastases were 5.7, 6.0, and 13.0 months, respectively. The mPFS in patients who started radiotherapy within or beyond 1 month after oligometastasis was 11.0 months and 5.3 months. The mPFS of patients with postoperative recurrence and initial unresectable were 13.0 and 6.0 months, respectively. Patients with 1 or more than 1 metastatic site showed a mPFS of 11.0 and 4.4 months, respectively. Those who had EGRF exon 21 mutation achieved a mPFS of 11.3 months, whereas those with EGRF exon 19 mutation did worse with a mPFS of 6.5 months. Cox regression model showed no variables significantly correlated with PFS difference. Univariate analysis identified age and smoking status were significantly associated with OS. The results of multivariate analysis indicated that there was no OS-related prognostic factors. Conclusion: Radiotherapy with continued TKIs is an efficacious treatment option in our patients. Age and smoking status were prognostic factors for OS. Our research showed that there was a better survival in patients with T790M mutation, EGRF exon 21 mutation, radiotherapy within 1 month after oligometastasis and bone metastases. However, this was not statistically significant. Prospective studies are needed to validate these clinical results.