Outcomes and Treatment Patterns in Patients with Oligometastatic Non-Small Cell Lung Cancer (NSCLC) Diagnosed at Craniotomy: A Single Institution Study

Abstract

NSCLC remains the largest cause of cancer death in the US and more than two-thirds of patients have either locally advanced or metastatic disease at diagnosis, including a large subset who present with symptomatic intracranial metastases. Historically, such patients had a uniformly poor prognosis, but in recent years, those with oligometastatic disease are increasingly being evaluated for thoracic consolidative radiation therapy (T-RT) due to the improvement in systemic therapies and prolonged progression-free survival (PFS). We retrospectively reviewed a cohort of patients with NSCLC who were diagnosed at craniotomy to establish a pathologic diagnosis and palliate symptoms. We assessed the types of treatments offered, PFS, overall survival (OS), and factors influencing outcome. A neurosurgical database of patients undergoing craniotomy in 2014-2015 was filtered to include those diagnosed with NSCLC at the time of that surgery and underwent further treatment at our institution. Medical records were reviewed for demographics, descriptors of the intracranial and extracranial burden of disease, systemic therapies, radiation therapy courses, PFS, and OS. Descriptive statistics were computed and 95% confidence intervals (CI) were constructed for Kaplan-Meier median survival estimates. Summary statistics were computed for factors associated with receipt of T-RT. Of 104 patients identified, 67 patients met inclusion criteria with available clinical information. Median age at time of presentation was 64 (range: 28-92). Median KPS was 80. Median number of brain metastases was 2 (range: 1-24), with a median volume of largest brain metastasis of 19cc (range: 1-75). WBRT was utilized for 38 patients (56.7%), while 28 (41.8%) had radiosurgery to the craniotomy cavity and other sites of intracranial disease. Two patients (3.8%) went straight to systemic therapy. Consolidative T-RT was used in 28 patients (41.8%); criteria for T-RT use were not pre-specified. Median PFS in patients who did and did not receive T-RT was 8.0 and 2.3 months, respectively (p<0.01). Median OS in patients who did and did not receive T-RT was 17.9 months and 4.3 months, respectively (p<0.01). Factors associated with T-RT receipt included higher KPS (p<0.01) and receipt of SRS for brain lesions (p=0.03). Patients presenting with intracranial metastases from NSCLC who are candidates for craniotomy appear to have prolonged OS as compared to historical benchmarks. In our cohort, consolidation T-RT was associated with prolonged survival. Although assignment of patients to T-RT in this retrospective cohort was not based on pre-specified criteria and might have been related to unknown bias, the hypothesis that T-RT improves OS in patients with oligometastatic disease should be further tested in prospective clinical trials.