Single organ metastatic disease and local disease status, prognostic factors for overall survival in stage IV non-small cell lung cancer: Results from a population-based study

• OS significantly longer in single organ metastatic disease compared to 2 or ⩾3 organs.
• Single organ metastases also prognostic in subgroup of 18FDG-PET-staged patients.
• Single organ metastases also prognostic in patients receiving anticancer treatment.
• In single organ metastases, low local disease (i.e. T1–2 and N0–1) best prognosis.

PurposeTo analyse the prognostic impact on overall survival (OS) of single versus multiple organ metastases, organ affected, and local disease status in a population based stage IV non-small cell lung cancer (NSCLC) cohort.MethodsIn this observational study, data were analysed of all histologically confirmed stage IV NSCLC patients diagnosed between 1 January 2006 and 31 December 2012 registered in the Netherlands Cancer Registry. Location of metastases before treatment was registered. Multivariable survival analyses [age, gender, histology, M-status, local disease status, number of involved organs, actual organ affected] were performed for all patients and for an 18fluorodeoxyglucose-positron emission tomography (18FDG-PET)-staged subgroup.Results11,094 patients were selected: 60% male, mean age 65 years, 73% adenocarcinoma. Median OS for 1 (N = 5676), 2 (N = 3280), and ⩾3 (N = 2138) metastatically affected organs was 6.7, 4.3, 2.8 months, respectively (p < 0.001). Hazard ratio (HR) for 2 versus 1 organ(s) was 1.33 (p < 0.001), for ⩾3 versus 1 organ(s) 1.91 (p < 0.001). Results were confirmed in the 18FDG-PET-staged cohort (N = 1517): patients with single organ versus 2 and ⩾3 organ metastases had higher OS (8.6, 5.7, 3.8 months, HR 1.40 and 2.17, respectively, p < 0.001). In single organ metastases, OS for low versus high TN-status was 8.5 versus 6.5 months [HR 1.40 (p < 0.001)]. 18FDG-PET-staged single organ metastases patients with low TN-status had a superior OS than those with high TN-status (11.6 versus 8.2 months, HR 1.62, p < 0.001).ConclusionPatients with single organ metastases stage IV NSCLC have a favourable prognosis, especially in combination with low TN status. They have to be regarded as a separate subgroup of stage IV disease.