Adjuvant Therapy Improves Survival for T2N0 Gastric Cancer Patients with Sub-optimal Lymphadenectomy.

BACKGROUND: The benefit of adjuvant therapy following resection of early stage, node-negative gastric adenocarcinoma following a margin negative (R0) resection is unclear. METHODS: The National Cancer Data Base was used to identify patients with a T2N0 gastric adenocarcinoma (tumor invasion into the muscularis propria) who underwent R0 resection. Patients treated with neoadjuvant therapy and those for whom lymph node count was unavailable were excluded from the analysis. Kaplan-Meier and Cox regression were used to evaluate differences in and predictors of overall survival. RESULTS: A total of 1687 patients underwent R0 resection for T2N0 gastric adenocarcinoma between 2003-2011. Adjuvant chemotherapy treatment was administered to 7.1 and 14.1 % received adjuvant chemoradiation; 65.4 % had <15 lymph nodes examined. Multivariate Cox regression identified higher Charlson score, <15 lymph nodes examined, higher tumor grade, and tumor location in the cardia as factors associated with significantly decreased overall survival. With a median follow-up of 36 months, the 5-year overall survival was 71 % for patients with ≥15 lymph nodes examined and 53 % for those with <15 lymph nodes (p < 0.001). In patients who had <15 lymph nodes examined, there was an overall survival benefit for adjuvant chemoradiation (hazard ratio 0.71, p = 0.043). In patients with ≥15 lymph nodes examined, no survival benefit for adjuvant therapy was identified (p > 0.74). CONCLUSIONS: Adequate lymph node dissection and pathologic staging is critical in directing optimal treatment of patients with early gastric cancer. Understaging as a result of suboptimal lymphadenectomy may explain the perceived benefit of adjuvant chemoradiation after an R0 resection for T2N0 gastric cancer.

Early National Experience with Laparoscopic Pancreaticoduodenectomy for Ductal Adenocarcinoma: A Comparison of Laparoscopic Pancreaticoduodenectomy and Open Pancreaticoduodenectomy from the National Cancer Data Base.

BACKGROUND: There is considerable debate about the safety and clinical equivalence of laparoscopic pancreaticoduodenectomy (LPD) and open pancreaticoduodenectomy (OPD) for pancreatic ductal adenocarcinoma (PDCA). STUDY DESIGN: We queried the National Cancer Data Base to identify patients undergoing LPD and OPD for PDCA between 2010 and 2011. Chi-square and Student's t-tests were used to evaluate differences between the 2 approaches. Multivariable logistic regression modeling was performed to identify patient, tumor, or facility factors associated with perioperative mortality. RESULTS: Four thousand and thirty-seven (91%) patients underwent OPD. Three hundred and eighty-four (9%) patients underwent LPD. There were no statistical differences between the 2 surgical cohorts with regard to age, race, Charlson score, tumor size, grade, stage, or treatment with neoadjuvant chemoradiotherapy. Laparoscopic pancreaticoduodenectomy demonstrated a shorter length of stay (10 ± 8 days vs 12 ± 9.7 days; p < 0.0001) and lower rates of unplanned readmission (5% vs 9%; p = 0.027) than OPD. In an unadjusted comparison, there was no difference in 30-day mortality between the LPD and OPD cohorts (5.2% vs 3.7%; p = 0.163). Multivariable logistic regression modeling predicting perioperative mortality controlling for age, Charlson score, tumor size, nodal positivity, stage, facility type, and pancreaticoduodenectomy volume identified age (odds ratio [OR] = 1.05; p < 0.0001), positive margins (OR = 1.45; p = 0.030), and LPD (OR = 1.89; p = 0.009) as associated with an increased probability of 30-day mortality; higher hospital volume was associated with a lower risk of 30-day mortality (OR = 0.98; p < 0.0001). In institutions that performed ≥10 LPDs, the 30-day mortality rate of the laparoscopic approach was equal to that for the open approach (0.0% vs 0.7%; p = 1.00). CONCLUSIONS: Laparoscopic pancreaticoduodenectomy is equivalent to OPD in length of stay, margin-positive resection, lymph node count, and readmission rate. There is a higher 30-day mortality rate with LPD, but this appears driven by a surmountable learning curve for the procedure.

The laparoscopic approach to distal pancreatectomy for ductal adenocarcinoma results in shorter lengths of stay without compromising oncologic outcomes.

BACKGROUND: The oncologic equivalence of laparoscopic distal pancreatectomy (LDP) to open pancreatectomy (ODP) for ductal adenocarcinoma (DAC) is not established. METHODS: The National Cancer Data Base was used to compare perioperative outcomes following LDP and ODP for DAC between 2010 and 2011. RESULTS: One hundred forty-five patients underwent LDP; 625 underwent ODP. Compared with ODP, patients undergoing LDP were older (68 ± 10.1 vs 66 ± 10.5 years, P = .027), more likely treated in academic centers (70% vs 59%, P = .01), and had shorter hospital stays (6.8 ± 4.6 vs 8.9 ± 7.5 days, P < .001). Demographic data, lymph node count, 30-day unplanned readmission, and 30-day mortality were identical between groups. Multivariable regression identified a lower probability of prolonged length of stay with LDP (odds ratio .51, 95% confidence interval .327 to .785, P = .0023). There was no association between surgical approach and node count, readmission, or mortality. CONCLUSION: LDP for DAC provides shorter postoperative lengths of stay and rates of readmission and 30-day mortality similar to OPD without compromising perioperative oncologic outcomes.

Surgical resection provides an overall survival benefit for patients with small pancreatic neuroendocrine tumors.

BACKGROUND: The optimal management of small (≤2 cm) pancreatic neuroendocrine tumors (PNETs) remains controversial. We evaluated these tumors in the National Cancer Data Base (NCDB) to determine if resection provides a survival advantage over observation. METHODS: The NCDB was queried to identify patients with nonmetastatic PNETs ≤2 cm treated between 1998 and 2006. Kaplan-Meier survival estimates, stratified by grade and treatment type, evaluated the difference in 5-year overall survival (OS) between patients who underwent resection and observation. Multivariable Cox regression was used to determine the importance of resection in OS. RESULTS: Three hundred eighty patients met inclusion criteria. Eighty-one percent underwent resection; 19% were observed. Five-year OS was 82.2% for patients who underwent surgery and 34.3% for those who were observed (p < 0.0001). When controlling for age, comorbidities, income, facility type, tumor size and location, grade, margin status, nodal status, surgical management, and nonsurgical therapy in the Cox model, observation [hazard ratio (HR) 2.80], poorly differentiated histology (HR 3.79), lymph node positivity (HR 2.01), and nonsurgical therapies (HR 2.23) were independently associated with an increase in risk of mortality (p < 0.01). CONCLUSION: Patients with localized PNETs ≤2 cm had an overall survival advantage with resection compared to observation, independent of age, comorbidities, tumor grade, and treatment with nonsurgical therapies.

Defining the Benefit of Adjuvant Therapy Following Resection for Intrahepatic Cholangiocarcinoma.

BACKGROUND: Intrahepatic cholangiocarcinoma (ICC) is rare but is increasing in incidence. While hepatectomy can be curative, the benefit of adjuvant therapy (AT) remains unclear. We utilized the National Cancer Data Base (NCDB) to isolate predictors of overall survival, describe the national pattern of AT administration, and identify characteristics of patients who experience a survival benefit from AT following resection for ICC. METHODS: Patients who were diagnosed with ICC between 1998 and 2006 and underwent surgical resection were identified through the NCDB. Kaplan-Meier and Cox regression analyses evaluated differences in overall survival between patients who received AT and those who did not. RESULTS: Overall, 638 patients who underwent surgery for ICC were identified. Multivariate Cox regression analysis identified positive lymph nodes, unexamined lymph nodes, positive margins, and lack of AT as predictors of decreased overall survival; 28.1 % of patients had positive margins while 20.1 % had positive nodes. These patients, as well as those who were younger and had fewer co-morbid conditions, were most likely to receive AT. After adjusting for other prognostic variables, patients were found to significantly benefit from AT if they had positive lymph nodes [chemotherapy: hazard ratio (HR) 0.54, p = 0.0365; chemoradiation: HR 0.50, p = 0.005] or positive margins (chemotherapy: HR 0.44, p = 0.0016; chemoradiation: HR 0.57, p = 0.0039). CONCLUSIONS: Positive lymph nodes and positive margins were associated with poor survival after resection for ICC. After controlling for other prognostic factors, AT was associated with significant survival benefits among patients with positive nodes or positive margins.

Impact of bilateral versus unilateral mastectomy on short term outcomes and adjuvant therapy, 2003-2010: a report from the National Cancer Data Base.

BACKGROUND: Rates of bilateral mastectomy (BM) have increased, but the impact on length of stay (LOS), readmission rate, 30-day mortality, and time to adjuvant therapy is unknown. METHODS: Using the National Cancer Data Base, we selected 390,712 non-neoadjuvant AJCC stage 0-III breast cancer patients who underwent either unilateral mastectomy (UM) or BM from 2003 to 2010 with and without reconstruction. We used chi-square and logistic regression models for the analysis. RESULTS: A total of 315,278 patients (81 %) had UM, and 75,437 (19 %) had BM; 97,031 (25 %) underwent reconstruction. The number of median days from diagnosis to UM increased from 19 days in 2003 to 28 days in 2010, and for BM, increased from 21 to 31 days (p < 0.001). BM was independently associated with a longer time to surgery when adjusting for patient, facility, and tumor factors and reconstruction (OR 1.11; 95 % CI 1.07-1.15; p < 0.001). Reconstructed patients were twice as likely to have a longer time to surgery (OR 2.07; 95 % CI 2.01-2.14; p < 0.001). The median LOS was 1 day (range 0-184 days) for UM versus 2 (range 0-182) for BM (p < 0.001); 30-day mortality and readmission rates were not different between BM and UM. The median number of days from diagnosis to definitive chemotherapy, hormonal therapy, and radiation therapy was significantly greater in the BM group. CONCLUSIONS: Delays to surgical and adjuvant treatment are significantly longer for BM irrespective of reconstruction, and these delays have increased over the study period. These findings can be used by clinicians to counsel patients on BM.

Role of lipase-generated free fatty acids in converting mesenteric lymph from a noncytotoxic to a cytotoxic fluid.

Recent studies have shown that mesenteric lymph plays a very important role in the development of multiple-organ dysfunction syndrome under critical conditions. Great efforts have been made to identify the biologically active molecules in the lymph. We used a trauma-hemorrhagic shock (T/HS) model and the superior mesenteric artery occlusion (SMAO) model, representing a global and a localized intestinal ischemia-reperfusion insult, respectively, to investigate the role of free fatty acids (FFAs) in the cytotoxicity of mesenteric lymph in rats. Lymph was collected before, during, and after (post) shock or SMAO. The post-T/HS and SMAO lymph, but not the sham lymph, manifested cytotoxicity for human umbilical vein endothelial cells (HUVECs). HUVEC cytotoxicity was associated with increased FFAs, especially the FFA-to-protein ratio. Addition of albumin, especially delipidated albumin, reduced this cytotoxicity. Lipase treatment of trauma-sham shock (T/SS) lymph converted it from a noncytotoxic to a cytotoxic fluid, and its toxicity correlated with the FFA-to-protein ratio in a fashion similar to that of the T/HS lymph, further suggesting that FFAs were the key components leading to HUVEC cytotoxicity. Analysis of lymph by gas chromatography revealed that the main FFAs in the post-T/HS or lipase-treated T/SS lymph were palmitic, stearic, oleic, and linoleic acids. When added to the cell culture at levels comparable to those in T/HS lymph, all these FFAs were cytotoxic, with linoleic acid being the most potent. In conclusion, this study suggests that lipase-generated FFAs are the key components resulting in the cytotoxicity of T/HS and SMAO mesenteric lymph.

The mucus layer is critical in protecting against ischemia-reperfusion-mediated gut injury and in the restitution of gut barrier function.

It is well documented that the gut injury plays a critical role in the development of systemic inflammation and distant organ injury in conditions associated with splanchnic ischemia. Consequently, understanding the mechanisms leading to gut injury is important. In this context, recent work suggests a protective role for the intestinal mucus layer and an injury-inducing role for luminal pancreatic proteases. Thus, we explored the role of the mucus layer in gut barrier function by observing how the removal of the mucus layer affects ischemia-reperfusion-mediated gut injury in rats as well as the potential role of luminal pancreatic proteases in the pathogenesis of gut injury. Ischemia was induced by the ligation of blood vessels to segments of the ileum for 45 min, followed by up to 3 h of reperfusion. The ileal segments were divided into five groups. These included a nonischemic control, ischemic segments exposed to saline, the mucolytic N-acetylcysteine (NAC), pancreatic proteases, or NAC + pancreatic proteases. Changes in gut barrier function were assessed by the permeation of fluorescein isothiocyanate dextran (molecular weight, 4,000 d) in ileal everted sacs. Gut injury was measured morphologically and by the luminal content of protein, DNA, and hemoglobin. The mucus layer was assessed functionally by measuring its hydrophobicity and morphologically. Gut barrier function was promptly and effectively reestablished during reperfusion, which was accompanied by the restoration of the mucus layer. In contrast, treatment of the gut with the mucolytic NAC for 10 min during ischemia resulted in a failure of mucus restitution and further increases in gut permeability and injury. The presence of digestive proteases by themselves did not exacerbate gut injury, but in combination with NAC, they caused an even greater increase in gut injury and permeability. These results suggest that the mucus layer not only serves as a barrier between the luminal contents and gut surface epithelia, but also plays a critical role in the maintenance and restitution of gut barrier function.

Loss of the intestinal mucus layer in the normal rat causes gut injury but not toxic mesenteric lymph nor lung injury.

There is substantial evidence that gut barrier failure is associated with distant organ injury and systemic inflammation. After major trauma or stress, the factors and mechanisms involved in gut injury are unknown. Our primary hypothesis is that loss of the intestinal mucus layer will result in injury of the normal gut that is exacerbated by the presence of luminal pancreatic proteases. Our secondary hypothesis is that the injury produced in the gut will result in the production of biologically active mesenteric lymph and consequently distant organ (i.e., lung) injury. To test this hypothesis, five groups of rats were studied: 1) uninstrumented naive rats; 2) control rats in which a ligated segment of distal ileum was filled with saline; 3) rats with pancreatic proteases placed in their distal ileal segments; 4) rats with the mucolytic N-acetylcysteine (NAC) placed in their distal ileal segments; and 5) rats exposed to NAC and pancreatic proteases in their ileal segments. The potential systemic consequences of gut injury induced by NAC and proteases were assessed by measuring the biological activity of mesenteric lymph as well as gut-induced lung injury. Exposure of the normal intestine to NAC, but not saline or proteases, led to increased gut permeability, loss of mucus hydrophobicity, a decrease in the mucus layer, as well as morphological evidence of villous injury. Although proteases themselves did not cause gut injury, the combination of pancreatic proteases with NAC caused more severe injury than NAC alone, suggesting that once the mucus barrier is impaired, luminal proteases can injure the now vulnerable gut. Because comparable levels of gut injury caused by systemic insults are associated with gut-induced lung injury, which is mediated by biologically active factors in mesenteric lymph, we next tested whether this local model of gut injury would produce active mesenteric lymph or lead to lung injury. It did not, suggesting that gut injury by itself may not be sufficient to induce distant organ dysfunction. Therefore, loss of the intestinal mucus layer, especially in the presence of intraluminal pancreatic proteases, is sufficient to lead to injury and barrier dysfunction of the otherwise normal intestine but not to produce gut-induced distant organ dysfunction.

Intestinal mucus layer preservation in female rats attenuates gut injury after trauma-hemorrhagic shock.

BACKGROUND: We tested the hypothesis that females are more resistant to trauma-hemorrhagic shock (T/HS)-induced gut injury than males, and this is related to better preservation of their intestinal mucus layer, which is influenced in turn by the estrus cycle stage at the time of injury. METHODS: Male, proestrus and diestrus female rats underwent a laparotomy (trauma) and 90 minutes of shock ( approximately 35 mm Hg). At 3 hours after reperfusion, terminal ileum was harvested and stained with Carnoy's Alcian Blue for mucus assessment, hematoxylin and eosin, and periodic acid schiff for villous and goblet cell morphology and injury. Ileal permeability was measured in separate intestinal segments using the ex vivo everted gut sac technique. RESULTS: When compared with males, proestrus female rats were significantly more resistant to T/HS-induced morphologic gut injury, as reflected in both a lower incidence of villous injury (14% vs. 22%; p < 0.05) and a lesser grade of injury (1.0 vs. 2.8; p < 0.05) as well as preservation of gut barrier function (17.9 vs. 32.2; p < 0.05). This resistance to gut injury was associated with significant preservation of the mucus layer (87% vs. 62%; p < 0.05) and was influenced by the estrus cycle stage of the female rats. There was a significant inverse correlation between mucus layer coverage and the incidence (r = 0.9; p < 0.0001) and magnitude (r = 0.89; p < 0.0001) of villous injury and gut permeability (r = 0.74; p < 0.001). CONCLUSIONS: The resistance of female rats to T/HS-induced intestinal injury and dysfunction was associated with better preservation of the intestinal mucus barrier and was to some extent estrus cycle-dependent. Preservation of the mucus barrier may protect against shock-induced gut injury and subsequent distant organ injury by limiting the ability of luminal contents such as bacteria and digestive enzymes from coming into direct contact with the epithelium.