Lymph node yield after colectomy for XXXX : is absence of mismatch repair a factor?

@entity1 @entity5 @entity5527 @entity14 @entity694
BACKGROUND: Nodal staging is crucial in determining the use of adjuvant chemotherapy for @entity694 . The number of metastatic lymph nodes has been positively correlated with the number of lymph nodes examined. Current guidelines recommend that at minimum 12 to 14 lymph nodes be assessed. In some studies, @entity5527 has been associated with lymph node yield. OBJECTIVE: The purpose of this work was to determine whether mismatch repair-deficient @entity14 are associated with increased lymph node yield. DESIGN: We queried an institutional database to analyze colectomy specimens with immunohistochemistry for mismatch repair genes in @entity1 treated for @entity14 between 1999 and 2012. Before 2006, immunohistochemistry was performed at the request of an oncologist or surgeon. After 2006, it was routinely performed for @entity1 <50 years of age. We measured the association of clinical and pathologic features with lymph node quantity. Fourteen predictors and confounders were jointly analyzed in a multivariable linear regression model. SETTINGS: The study was conducted at a single tertiary care institution. @entity1 : Tissue specimens from 256 @entity1 were reviewed. MAIN OUTCOME MEASURES: The correlation of @entity5 , @entity1 , and operative variables to the yield of mesenteric lymph nodes was measured. RESULTS: Of 256 colectomy specimens reviewed, 94 had @entity5527 . On univariate analysis, @entity5527 was associated with lower lymph node yield, older @entity1 age, right-sided @entity5 , and poor differentiation. The linear regression model identified 5 variables with independent relationships to lymph node yield, including @entity1 age, specimen length, lymph node ratio, perineural invasion, and @entity5 size. A positive correlation was observed with @entity5 size, specimen length, and perineural invasion. @entity5 location had a more complex, nonlinear, quadratic relationship with lymph node yield; proximal @entity5 were associated with a higher yield than more distal lesions. @entity5527 was not independently associated with lymph node yield. LIMITATIONS: Mismatch repair immunohistochemistry based on @entity1 age, family history, and pathologic features may reduce the generalizability of these results. Our sample size was too small to identify variables with small measures of effect. The retrospective nature of the study did not permit a true assessment of the extent of mesenteric resection. CONCLUSIONS: @entity1 age, length of bowel resected, lymph node ratio, perineural invasion, @entity5 size, and @entity5 location were significant predictors of lymph node yield. However, when controlling for surgical and pathologic factors, mismatch repair protein expression did not predict lymph node yield.
