90th Annual Meeting Abstracts
The Effect of Neo-Adjuvant Chemoradiation on the Diagnostic Value of Lymph Nodes After Surgery for Rectal Cancer
*Coen L Klos1,2, Paul C Shellito, MD1, David W Rattner, MD1, *Richard A Hodin, MD1, James C Cusack, MD1, *Liliana Bordeianou, MD1, *Patricia Sylla, MD1, *Theodore S Hong, MD1, *Lawrence S Blaszkowsky, MD1, *David P Ryan, MD1, *Gregory Y Lauwers, MD1, David L Berger, MD1
1Massachusetts General Hospital, Boston, MA;2Universiteit van Amsterdam, Amsterdam, Netherlands
Objective: To define the importance of the number of lymph nodes harvested and lymph node positivity in patients with rectal cancer who underwent neo-adjuvant therapy.
Design: Retrospective cohort review, extending from February 20, 2000, to December 31, 2008.
Setting: Tertiary care referral center.
Patients: 390 consecutive patients (248 males and 142 females) with histologically confirmed rectal cancer. Patient ages ranged from 24 to 98 years (mean 63 years). Postoperative follow-up, disease-free survival and survival were confirmed via medical record review.
Main outcome measures: We assessed the impacts that lymph node positivity and total lymph node harvest had on survival and recurrences in patients undergoing surgery after neo-adjuvant treatment for rectal cancer. Survival analysis using Cox proportional hazard models were conducted to compare outcomes controlling for age, gender, race, metastases recognized before surgery, T-stage and adjuvant therapy.
Results: 222 of the 390 patients (57%) underwent neo-adjuvant therapy. Among the 222, 75 patients (34%) had pathologic lymph nodes. There was a significant decrease in time to death (adjusted hazard ratio [HR]=2.89, p=0.002), a significant decrease in time to local recurrence (HR=6.57, p=0.030), and a tendency towards shorter time to distant recurrence (HR=2.24, p=0.13) in patients with positive lymph nodes when compared to those with negative lymph nodes. There was no significant difference in all three outcomes between node negative patients with 11 or fewer lymph nodes harvested versus patients with the baseline of 12 or more lymph nodes harvested.
Conclusion: After neo-adjuvant treatment, absolute numbers of lymph nodes harvested has little bearing on prognosis whereas lymph node positivity after neoadjuvant treatment is a surrogate for significantly higher local recurrence rates and a significant decrease in survival.