The Influence of Histologic Subtype in Predicting Survival of Lung Cancer Patients With Spinal Metastases.

Abstract

Retrospective analysis. Recent advancements in systemic treatment of lung cancer have significantly improved the survival of patients with certain histolopathologic and molecular subtypes. Existing prognostic scores do not account for this and patients with lung cancer spinal metastases are grouped together as poor prognostic candidates, and consequently, some may be inappropriately denied palliative spine surgery. The objective of the study was to study whether the expected survival in patients with lung cancer spinal metastases is affected by histolopathologic and molecular subtypes in the context of modern systemic therapy. We retrospectively reviewed all patients with histologically confirmed lung cancer treated for spinal metastases at our institution between 2001 and 2012. Patients' demographics, histopathologic details, treatment modalities, and survival data were collected. The primary outcome was survival from time of spinal metastases diagnosis. The Cox regression analysis was used to evaluate the influence of tumor histology, molecular profile and treatment modality on survival. The Kaplan-Meier survival analysis was conducted to compare lung cancer subtypes, as well as various treatment regimens. Out of 180 patients, 51 underwent surgery for spinal metastases. Female sex (P=0.019), absence of palsy (P=0.023), good Karnofsky performance scores (P<0.001), and non-small cell lung cancer (NSCLC) (P=0.002) were favorable prognostic factors. Patients who received systemic therapy, including tyrosine kinase inhibitors, platinum doublet chemotherapy, or both showed increased survival (P<0.01). The median survival time was 2.40 months [95% confidence interval (CI), 2.13-2.68] in the small cell lung cancer cohort, with no patients surviving past a year; 5.10 months (95% CI, 3.78-6.41) in the NSCLC cohort, with 25.9% 1-year survival; and 13.3 months (95% CI, 2.26-24.40) in adenocarcinoma patients who received both tyrosine kinase inhibitors and platinum doublet therapy, with 50.0% 1-year survival. NSCLC, systemic therapy, female sex, absence of palsy and good Karnofsky performance scores are all independent favorable prognostic factors for patients with lung cancer spinal metastases. These should be routinely considered during prognostication.