The prognostic value of lymph node ratio after neoadjuvant chemoradiation and XXXX surgery.

@entity1 @entity797 @entity5
BACKGROUND: Neoadjuvant chemotherapy decreases total lymph nodes harvested and possibly affects lymph node staging after total mesorectal excision in @entity1 with @entity5 . OBJECTIVE: This study aimed to compare staging by lymph node ratio with staging by absolute number of positive lymph nodes. DESIGN: This study is a retrospective cohort review. SETTING: : A tertiary care referral center was the setting for this investigation. @entity1 : A total of 281 consecutive @entity1 who underwent neoadjuvant chemoradiation and total mesorectal excision after histologically confirmed @entity5 between January 1, 1998 and December 31, 2008 were included in this study. MAIN OUTCOME MEASURES: Lymph node ratio is the number of positive lymph nodes divided by the total number of lymph nodes within one sample. Risk categories of low (0 to < 0.09); medium (0.09 to < 0.36); and high (>=  0.36) for lymph node ratio were chosen by significance with the use of @entity797 proportional hazards models. These categories were then used in a reclassification table and compared with positive lymph node stage: low (0 positive nodes), medium (1-3 nodes), and high (> 3) by 5-year mortality rates. RESULTS: The majority (87%) of @entity1 were concordant in risk assessment. Thirty @entity1 were downstaged to lower risk lymph node ratio categories without showing actual lower mortality rates. Seven @entity1 were upstaged to a high-risk lymph node ratio category with a supporting higher 5-year mortality rate. When limiting the analysis to those with fewer than 12 nodes, 136 (95%) @entity1 were concordant in risk assessment; all 30 incorrectly downstaged @entity1 were removed, but the 7 correctly upstaged @entity1 remained. CONCLUSIONS: @entity1 who undergo neoadjuvant chemoradiation before @entity5 surgery frequently have fewer than 12 lymph nodes harvested despite maintaining vigorous surgical standards. Lymph node ratios may provide excellent prognostic value and are possibly a better independent staging method than absolute positive lymph node counts when less than 12 lymph nodes are harvested after neoadjuvant treatment.
