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The incidence and clinical impact of bone metastases in non-small cell lung cancer.
Abstracts that were granted an exception in accordance with ASCO's Conflict of Interest Policy are designated with a caret symbol (^).
Background: Non-small cell lung cancer (NSCLC) is the leading global cause of cancer death. Bone metastases (BM) in NSCLC are a common cause of morbidity, but use of bone targeted agents (BTA) is variable. We investigated the incidence and impact of BM in an unselected NSCLC population. Methods: With ethics approval, we performed a retrospective chart review of all patients (pts) with NSCLC seen at our institution in 2007. Baseline demographics, stage and initial treatment goals were recorded. In pts with advanced disease (mNSCLC) metastatic sites were identified. In BM pts, skeletal related events (SRE), interventions and outcomes were recorded. Results: In total, 374 pts were identified. Median age was 68 years (IQR 60-76), 54% female. Histological subtypes were adenocarcinoma (36%), squamous (18%), and other (46%). Overall 91% were current or ex-smokers. At initial diagnosis 37% had stage I-IIIa, 18% IIIb and 46% stage IV disease. A total of 160 pts (43%) were treated with curative intent; 211 (56%) were considered palliative. Of the 160 curative therapy pts, 90 (56%) subsequently relapsed, with a median time from diagnosis to relapse of 14.9 months. Of the 301 pts with mNSCLC, common sites of metastasis were lung/pleura (80%), mediastinal lymph nodes (69%), bone (39%), brain (30%), and liver (24%). In total 116 pts had BM; a higher incidence was observed in pts ≤70 years than pts >70 (36% vs 23%). SREs were observed in 69 pts (59%), the median number of SREs per BM pt was 1 (0-16). The incidence of SREs was radiotherapy (63%), fractures (22%), spinal cord compression (6%) and surgery to bone (5%). Factors associated with ≥2 SREs were smoking status (28% never smokers vs 9% ex/current smoker) and younger age (15% vs 5%). In BM pts, 64% required opioid analgesia, only 6% received BTA. Overall survival (OS) in pts with mNSCLC was 7.3 months (IQR 3.1-20.5). Pts with BM had significantly shorter OS compared to those without BM (5.5 vs. 9.9 months, p=0.02). Median OS in pts with or without SRE were 5.5 and 6.4 months (p=0.58). Conclusions: BM in NSCLC pts are common, and most pts will develop an SRE and/or require opioids. In mNSCLC, the presence of BM is associated with significantly shorter survival, which raises challenging questions around the use of BTA.