MA01.09 Concomitant SBRT and EGFR-TKI Versus EGFR-TKI Alone for Oligometastatic NSCLC: A Multicenter, Randomized Phase II Study

Stereotactic ablative radiotherapy for acquired resistance to EGFR therapy in metastatic non-small cell lung cancer

The advent of targeted therapy has transformed the treatment paradigm and survival of patients with metastatic non-small cell lung cancer (NSCLC) with driver mutations. The development of acquired resistances during treatment with tyrosine kinase inhibitors (TKIs) impedes a prolonged survival in many patients. This fact is leading to the use of locally ablative therapies such as stereotactic ablative radiotherapy (SABR) to counter these resistances. SABR is a non-invasive treatment that can be delivered in multiple locations and has already proven effective in oligometastatic disease. Clinical evidence suggests that the combination of SABR with TKIs prolongs progression-free survival (PFS) in metastatic NSCLC patients with mutations in epidermal growth factor receptor (EGFR), with international guidelines recommending their use in unfavorable scenarios such as oligoprogressive disease. In this publication, we have reviewed the available evidence on EGFR-TKIs resistance mechanisms and the combination of SABR with TKI in metastatic NSCLC with EGFR mutations. We also describe the utility and clinical recommendations of this combination in oligometastatic and oligoprogressive disease.

Efficacy and Failure Patterns of Early SBRT to the Primary Tumor in Advanced EGFR-Mutation-Positive Lung Cancer with EFGR-TKI Treatment: A Prospective, Single Arm, Phase II Study

Early stereotactic body radiation therapy (SBRT) to the primary tumor combined with epidermal growth factor receptor tyrosine kinase inhibitor (EFGR-TKI) treatment may increase progression-free survival (PFS) by delaying resistance in patients with advanced EGFR-mutant non-small cell lung cancer (NSCLC). In this prospective, single arm, phase II study, patients with advanced NSCLC were treated with EGFR-TKI (icotinib 125 mg tid or gefitinib 250 mg qd) for one month followed by SBRT (40-60 Gy/5-8 F/5-10 d) to the primary tumor with concurrent EGFR-TKI until disease progression. The primary endpoint was PFS and the patterns of failure. Overall survival (OS) and adverse effects (AEs) were secondary endpoints. Overall, 41 advanced NSCLC patients with EGFR mutations received treatment with 24.42 months of median follow-up time. On average, SBRT was initiated 1.49 months after EGFR-TKI administration. Tumors were found to have an average shrinkage rate of 42.50%. Median PFS was 15.23 months (95% CI 13.10-17.36), while median OS was 27.57 months (95% CI 23.05-32.09). Thirty-three patients were found to have disease progression, of which new site failure (NF) (22 patients, 66.66%) was the most common pattern, followed by original site failure (OF) (7 patients, 21.21%) and simultaneous OF/NF (ONF) (4 patients, 12.12%). There were no Aes equal to or greater than grade 3, with the most frequent AE being radiation pneumonitis. Therefore, administering therapy targeted at the primary tumor using early SBRT after EGFR-TKI initiation is a new potentially safe and effective approach to treat EGFR-mutant advanced NSCLC.

Primary lesion radiotherapy during first-line icotinib treatment in EGFR-mutated NSCLC patients with multiple metastases and no brain metastases: a single-center retrospective study

BACKGROUND

The most frequent mode of progression in the majority of non-small cell lung cancer (NSCLC) patients treated with  Epidermal growth factor - receptor tyrosine kinase inhibitors (EGFR-TKIs) is failure to respond to treatment at the primary lesion, suggesting that concurrent radiotherapy (CRT) to the primary lesion (CPRT) during first-line treatment with EGFR-TKI may be a novel therapeutic approach with a potential of additional benefit for metastatic NSCLC. Therefore, this study investigated the progression-free survival (PFS) and safety of CPRT during first-line icotinib treatment in NSCLC patients with EGFR mutations.

METHODS

EGFR-mutant NSCLC patients diagnosed with limited multiple metastases were treated with first-line icotinib. The decision to treat the primary lesions with radiation largely depended on the patient's preference. The study endpoints included PFS, toxicity, progression pattern, and acquisition of the T790M mutation.

RESULTS

The median PFS in the CPRT and Non-CPRT groups was 13.6 and 10.6 months (hazard ratio [HR] 0.23, 95% confidence interval [CI] 0.15-0.37, P < 0.001). Subgroup analysis showed that the results were statistically significant with 14.7 and 11.5 months for the 19del mutation (HR 0.20, 95% CI 0.10-0.40, P < 0.001) and 12.9 and 9.9 months for the L858R mutation (HR 0.25, 95% CI 0.13-0.48, P < 0.001). There were no reports of interstitial pneumonia associated with treatment at grade 4 or above. Patients who received CPRT during first-line icotinib treatment had the potential to decrease the primary lesion progression (P < 0.05) without increasing newly metastatic lesions (P > 0.05). The proportion of acquired T790M mutations was 26.7% and 45.7% in both groups (P > 0.05).

CONCLUSION

This study suggests that CPRT is a viable option for patients with EGFR-sensitive mutations in NSCLC with limited multiple metastases during first-line icotinib treatment, which can significantly improve PFS with acceptable toxicities. Data on progression patterns and T790M mutations suggest the need to further investigate the benefits of radiation treatment from a molecular perspective.

Local Therapy Combined With First-Line EGFR Tyrosine Kinase Inhibitor Achieves Favorable Survival in Patients With EGFR-Mutant Metastatic Non-Small Cell Lung Cancer

BACKGROUND

EGFR tyrosine kinase inhibitor (TKI) is recommended as the first-line therapy for patients with EGFR-mutant metastatic non-small cell lung cancer (NSCLC). Yet, resistance often occurs in 1 year after therapy and most progressions occur at the initial sites of disease. Addition of local therapy to the first-line TKI therapy may delay the progression and provide survival benefit to the patients.

METHODS

From 2010 to 2017, metastatic NSCLC patients with EGFR activating mutations who received first-line TKI and relatively radical local therapy (RRLT) were reviewed. RRLT was defined as local curative therapy to the main site or any intensity of local therapy to all sites of disease. The Kaplan-Meier method and log-rank test were used for survival estimation and comparison.

RESULTS

A total of 45 patients were included in this retrospective study with a median follow-up of 48.0 months. The median progression-free survival (PFS) and overall survival (OS) was 17.0 months (95% confidence interval [CI]: 14.6-19.3) and 55.0 months (95% CI: 49.3-60.6), respectively. Univariate analysis indicated that age ⩽ 60 years (P = .019), first-line TKI duration ⩾ 10 months (P = .028), and accumulated TKI duration ⩾ 20 months (P = .016) were significantly associated with favorable OS. Among the 36 patients who progressed during the follow-up, 55.8% of the progressions occurred at the new sites. RRLT combined with TKI did not show any severe toxicity to the patients.

CONCLUSIONS

Combined application of RRLT and first-line TKI may improve the survival and alter the pattern of failure for metastatic NSCLC patients with EGFR activating mutations.

Detailed Analysis and Radiomic Prediction of First Progression Sites of First-Line Targeted Therapy for EGFR-Mutant Lung Adenocarcinoma Patients With Systemic Metastasis

Background

We aimed to analyze the first progression sites of first-line tyrosine kinase inhibitor (TKI) treatment for EGFR-mutant lung adenocarcinoma patients with systemic metastasis to recognize the potential candidates who might benefit from radiotherapy and establish a radiomic-based model to predict the first progression sites.

Materials and Methods

We retrospectively collected the clinical information and pre-treatment chest CT images of patients in Shanghai Chest Hospital from 2013 to 2017. All patients were diagnosed with stage IV EGFR-mutant lung adenocarcinoma and received TKI as first-line treatment. The first progression sites and survival were analyzed. The pre-treatment chest non-contrast CT images were utilized to establish a radiomic-based model to predict the first progression sites.

Results

We totally collected 233 patients with systemic metastasis, among whom, there were 84 (36.1%) and 149 (63.9%) patients developing first progression in original lesions (OP) and new lesions (NP), respectively. The PFS and OS of patients with OP were longer than those with NP (PFS 11 months vs. 8 months, p = 0.03, OS 50 months vs. 35 months, p = 0.046). For 67.9% of the patients with OF, disease progressed within five sites (oligoprogression). The radiomic-based model could predict the progression sites with an AUC value of 0.736, a specificity of 0.60, and a sensitivity of 0.750 in the independent validation set.

Conclusion

Among patients with systemic metastasis, there were 36.1% of patients developing OP at first progression who had a better prognosis than those developing NP. Patients with OP may be potential candidates who might benefit from radiotherapy. Radiomics is a useful method to distinguish patients developing OP and could provide some indications for radiotherapy.

Management of Oligometastatic Disease in Advanced Non-Small Cell Lung Cancer

Non-small cell lung cancer with very limited extent of metastatic spread commonly is termed, oligometastatic disease (OMD), and typically described as no more than 3 to 5 lesions. Definitive local therapy potentially leads to significant improvement in progression-free survival and overall survival. OMD may occur de novo prior to initiation of systemic therapy or as an induced state after initiation of systemic therapy. Although prospective data are limited to small trials, they have consistently supported local therapy as an appropriate consideration if not a clear standard of care for well-selected patients. Several trials in OMD are ongoing.