Apical lymphadenectomy during low ligation of the IMA during rectosigmoid resection for cancer

Background

Low ligation of the inferior mesenteric artery with preservation of the left colic artery may decrease the risk of colorectal anastomotic ischemia compared to high ligation at its origin. Low ligation leaves apical nodes in situ and is therefore paired with apical lymphadenectomy. We sought to compare relevant oncologic outcomes between high ligation and low ligation plus apical lymphadenectomy in rectosigmoid resection for colorectal cancer.

Methods

We conducted a retrospective cohort study. Patients receiving a rectosigmoid resection for cancer between January 2012 and July 2018 were included. Patients with metastatic disease and those who underwent low ligation without apical lymphadenectomy were excluded. Our primary outcome was nodal yield/metastasis. Secondary outcomes included perioperative complications, local recurrence, and overall survival.

Results

Eighty-four patients underwent high ligation and 89 low ligation plus apical lymphadenectomy (median follow-up 20 months). In the low-ligation group, a median of 2 (interquartile range = 1–3) apical nodes was resected; 4.1% were malignant, increasing pathologic stage in 25% of these patients. There were no differences in nodal yield, complications, anastomotic leak, local recurrence, or overall survival.

Conclusion

No differences were identified between high ligation and low ligation plus apical lymphadenectomy with respect to relevant clinical outcomes. Prospective trial data are needed to robustly establish the oncologic benefit and safety of the low ligation plus apical lymphadenectomy technique.

Adequacy of lymph node harvest following colectomy for obstructed and nonobstructed colon cancer

BACKGROUND

Technical and clinical differences in resection of obstructed and non-obstructed colon cancers may result in differences in lymph node retrieval. The objective of this study is to compare the lymph node harvest following resection of obstructed and nonobstructed colon cancer patients.

METHODS

A retrospective analysis utilizing the 2014-2018 NSQIP colectomy targeted data set was conducted. One-to-one coarsened exact matching (CEM) was utilized between patients undergoing resection for obstructed and non-obstructed colon cancer. The primary outcome was the adequacy of lymph node retrieval (LNR, ≥12 nodes).

RESULTS

CEM resulted in 9412 patients. Patients with obstructed tumors were more likely to have inadequate LNR (13.3% vs 8.2%, p < .001) compared to those with nonobstructed tumors. Multivariate analysis demonstrated that patients with obstructing tumors had worse LNR compared to non-obstructed tumors (odds ratio [OR]: 0.74, 95% confidence interval [CI]: 0.62-0.87; p < .005). Increased age (OR: 0.99, 95% CI: 0.098-0.99), presence of preoperative sepsis (OR: 0.70, 95% CI: 0.055-0.90), left-sided and sigmoid tumors compared to right-sided (OR: 0.64, 95% CI: 0.51-0.81; OR: 0.69, 95% CI: 0.58-0.82, respectively), and open surgical resection compared to an minimally invasive surgical approach were associated with inadequate LNR (p < .05).

CONCLUSION

This study demonstrated that resection for obstructing colon cancer compared to non-obstructed colon cancer is associated with increased odds of inadequate lymph node harvest.

Benefits of minimally-invasive surgery for sigmoid and rectal cancer in older adults compared with younger adults: Do older adults have the most to gain?

INTRODUCTION

Randomized trials demonstrated oncologic safety and short-term benefits of laparoscopy. We investigated if the benefit of laparoscopy on short-term outcomes is greater for older adults compared with younger adults.

METHODS

We identified all older (≥70 years old) and younger (<70) adults with primary sigmoid and rectal cancer treated with resection between 2002 and 2018 from an institutional database. We compared 30-day postoperative outcomes using multivariable logistic regression with an interaction term between age group and surgical approach. Primary outcomes were death, major (Clavien-Dindo III-IV) and minor (Clavien-Dindo I-II) complications, and wound complications.

RESULTS

We included 792 patients, 293 (37%) older and 499 (63%) younger. Use of laparoscopy was similar between age groups: 120/293 (41%) older, 204/499 (41%) younger (p = .98). All patients had 30-day follow-up. Compared with open resection, minimally-invasive resection was associated with a greater reduction in deaths in older adults than in younger adults (absolute difference in older adults 7.0% less versus 2.1% less in younger adults; adjusted odds ratio [aOR] older 3.01, 95% confidence interval [CI] 1.31-7.33; aOR younger 0.31, 95% CI 0.05-1.24; interaction p = .01). Similarly, minimally-invasive resection was associated with a greater reduction in major complications in older adults than in younger adults (absolute difference in older adults 6.4% less versus 2.4% less in younger adults; aOR older 1.91, 95% CI 1.07-3.41; aOR younger 0.70, 95% CI 0.34-1.38; interaction p = .03).

CONCLUSIONS

Minimally-invasive compared with open surgery demonstrated a differential benefit on postoperative death and major complications between younger and older adults.

Deficiency of a glycogen synthase-associated protein, Epm2aip1, causes decreased glycogen synthesis and hepatic insulin resistance

Glycogen synthesis is a major component of the insulin response, and defective glycogen synthesis is a major portion of insulin resistance. Insulin regulates glycogen synthase (GS) through incompletely defined pathways that activate the enzyme through dephosphorylation and, more potently, allosteric activation. We identify Epm2aip1 as a GS-associated protein. We show that the absence of Epm2aip1 in mice impairs allosteric activation of GS by glucose 6-phosphate, decreases hepatic glycogen synthesis, increases liver fat, causes hepatic insulin resistance, and protects against age-related obesity. Our work identifies a novel GS-associated GS activity-modulating component of insulin resistance.