Time-dependent trends in lymph node yield and impact on adjuvant therapy decisions in colon cancer surgery: an international multi-institutional study.
BACKGROUND
Lymph node yield (LNY) and accuracy of nodal assessment are critical to staging and treatment planning in colon cancer (CC). A nationally agreed upon 12-node minimum is a quality standard in CC. The impact of this quality measure on LNY and impact on therapeutic decisions are evaluated in two international, multi-center, prospective trials comprising a well-characterized cohort assembled over 8 years (2001-2009) with long-term follow-up.


OBJECTIVE
Quality adherence through increased LNY improves staging accuracy and impacts adjuvant therapy decisions.


METHODS
Retrospective analysis of prospective data to assess time-dependent LNY, the dependent variable in multivariate linear regression analysis adjusted for age, gender, body-mass-index (BMI), tumor size/stage/grade, anatomic location and surgery date.


RESULTS
Two-hundred-forty-five patients with non-metastatic CC, median age 70 years, BMI 26 kg/m(2), tumor size 4.0 cm, and LNY 17 nodes were studied. Seventy-two percent had T3 (70 %)/T4 (2 %) tumors. Adherence to the 12-node minimum was 70 %(2001-2002), 81 % (2003-2004), 90 % (2005-2006), 94 % (2007-2008). LNY significantly increased over time (Median LNY: 2001-2004 = 15 vs. 2005-2008 = 17; P < 0.001) on multivariate analysis controlling for tumor size (P < 0.001), and right-sided tumor location (P < 0.001). Adjuvant therapy administration and indication for chemotherapy according to LNY (<12 vs. 12 + LNs = 33 % vs. 39 %; P = 0.48) and time period (2001-2004 vs. 2005-2008 = 39 % vs. 37 %; P = 0.89) remained unchanged.


CONCLUSIONS
Despite the independent predictors of nodal yield (tumor location and size), year of study still had a significant impact on nodal yield. Despite increased quality adherence and LNY over time, there appears to be a delayed impact on adjuvant therapy decisions once quality standard adherence takes effect.
Department of Surgery, Walter Reed Army Medical Center, Washington, DC, USA. alexander.stojadinovic@med.navy.mil
Alexander
A
Stojadinovic
Aviram
A
Nissan
Zev
Z
Wainberg
Perry
P
Shen
Martin
M
McCarter
Mladjan
M
Protic
Robin S
RS
Howard
Scott R
SR
Steele
George E
GE
Peoples
Anton
A
Bilchik
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017024:Chemotherapy, Adjuvant; D003110:Colonic Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D003657:Decision Making; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007390:International Agencies; D008198:Lymph Nodes / Q000473:pathology / Q000601:surgery*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D012189:Retrospective Studies; D015996:Survival Rate; D013997:Time Factors