ABSTRACT
Purpose: To identify the incidence, preoperative risk factors, and prognosis associated with pathologically positive lymph node (pN+) in patients undergoing a sub-lobar resection (SLR). Methods: This is a retrospective study using the National Cancer Database (NCDB) from 2004 to 2014 analyzing SLR excluding those with any preoperative chemotherapy and/or radiation, follow-up <3 months, stage IV disease, or >1 tumor nodule. Multivariable modeling (MVA) was used to determine factors associated with overall survival (OS). Propensity score matching (PSM) was used to determine preoperative risk factors for pN+ in patients having at least one node examined to assess radiation's effect on OS in those patients with pN+ and to determine whether SLR was associated with inferior OS as compared to lobectomy for each nodal stage. Results: A total of 40,202 patients underwent SLR, but only 58.3% had one lymph node examined. Then, 2,615 individuals had pN+ which decreased progressively from 15.1% in 2004 to 8.9% in 2014 (N1, from 6.3 to 3.0%, and N2, from 8.4 to 5.9%). A lower risk of pN+ was noted for squamous cell carcinomas, bronchioloalveolar adenocarcinoma (BAC), adenocarcinomas, and right upper lobe locations. In the pN+ group, OS was worse without chemotherapy or radiation. Radiation was associated with a strong trend for OS in the entire pN+ group (p = 0.0647) which was largely due to the effects on those having N2 disease (p = 0.009) or R1 resections (p = 0.03), but not N1 involvement (p = 0.87). PSM noted that SLR was associated with an inferior OS as compared to lobectomy by nodal stage in the overall patient population and even for those with tumors <2 cm. Conclusion: pN+ incidence in SLRs has decreased over time. SLR was associated with inferior OS as compared to lobectomy by nodal stage. Radiation appears to improve the OS in patients undergoing SLR with pN+, especially in those with N2 nodal involvement and/or positive margins.
ABSTRACT
The extent to which rats express anxiety-like behavior on the elevated plus-maze (EPM) depends on their previous maze experience. Open-arm avoidance develops in maze-experienced rats, and is often accompanied by a diminished anxiolytic response to benzodiazepines. Regions of the dorsal raphe nucleus (DRN) were examined in male Sprague-Dawley rats using c-Fos and serotonin immunohistochemistry following a single exposure, a second exposure or no exposure to the EPM. We then examined the effect of the benzodiazepine anxiolytic chlordiazepoxide (CDP, 5 mg/kg) on EPM behavior and DRN neural activity. Enhanced open-arm avoidance was evident on the second EPM trial in both experiments. The observed pattern of c-Fos expression suggests that the first exposure to the maze activates serotonin cells in the rostral and dorsal regions of the DRN and that only the dorsal subregion is activated by a second exposure. CDP increased open-arm exploration during the first trial, which corresponded to decreased 5-hydroxytryptamine (5-HT) activity in the rostral and ventral subregions of the DRN. However, 5-HT activity in the DRN was reduced in rats on the second maze trial compared with the first trial, when CDP had no effect on open-arm exploration. These results suggest that open-arm avoidance in maze-experienced rats can be characterized as a coping response that is mediated by specific populations of 5-HT neurons in the DRN.