Kirmani BH, et al. - In this retrospective analysis, researchers assessed the long-term survival and disease-free survival of patients with the identical clinical TNM stage with and without occult N2 disease, presuming that such occult disease, too small or inactive to be recognized during pre-operative multi-modality staging, may signify low volume disease that may have equivalent survival to patients with similar stage at clinical, pre-operative assessment. They found that the rate of N2 disease for different tumor histological types was not different. Cases with occult N2 disease vs without showed 5-year survival of 35.8% vs 62.5%, respectively. Median survival was 34 months vs 84 months with occult N2 disease vs without, respectively. Although occult N2 disease, even with low volume and positron emission tomography non-avid disease, did not run an indolent course, it still should be considered a risk factor for poorer prognosis.