[626] Tumor Deposits in Rectal Adenocarcinoma after Neoadjuvant Chemoradiation Are Associated with Advanced Stage and Tumor Recurrence.

Purva Gopal, Mary Kay Washington. Vanderbilt University Medical Center, Nashville, TN

Background: Pericolonic tumor deposits (TD) in colorectal carcinoma (CRC) have been associated with poor prognosis; however, the nature and impact on outcome of TDs in rectal carcinoma following neoadjuvant chemoradiation (NCR) are unexplored. The aim of this study is to assess the prevalence of TD in rectal cancer patients treated with NCR and the association of TDs with clinical pretreatment tumor extent, clinical outcome, and overall survival (OS). Our hypothesis is that TDs following neoadjuvant therapy are associated with poor outcome in rectal cancer.
Design: This retrospective study included 461 rectal carcinoma resections from 1989-2010 evaluated for TD and history of NCR. TD were defined as irregular tumor deposits in perirectal fat discontinuous from the primary tumor, with infiltrative borders, no surrounding lymphocytes, and close association with large nerves or vessels. Medical records were reviewed for pretreatment clinical stage, total number of positive lymph nodes (pN+), vascular invasion (LVI), perineural invasion (PNI) local recurrence (LR), distant metastases (DM), and OS.
Results: Of 461 cases, 219 were treated with NCR and 233 untreated. Forty-nine (10.6%) contained TD (20 NCR and 29 without NCR). An additional 96 cases contained residual tumor after NCR without TD. Patients with TD after NCR had significantly higher pN+ compared to untreated patients with TD (p=0.001), and higher pretreatment T stage (cT3/T4) compared to untreated patients with TD (p=0.005). Patients with TD after NCR had significantly less LVI (6/20) compared to untreated patients with TD (24/29, p=0.0003). There was no significant difference between these 2 groups in PNI, DM, LR, and OS. Patients with TD after NCR had a significant increase in total number pN+ (p=0.0001), LR (p=0.03), DM (p=0.045), LVI (p=0.03) and PNI (p=0.007) compared to cases without TD after NCR. There was no significant difference in OS between these 2 groups.
Conclusions: The association with deeply invasive (cT3/T4) tumors suggests that many TDs after neoadjuvant therapy result from discontinuous eradication of tumor. While there was no impact on OS, the presence of TD after neoadjuvant therapy is associated with more advanced disease and tumor recurrence (more positive lymph nodes, LVI, PNI, local recurrence, metastases), as compared to patients without TD after neoadjuvant therapy. TDs after neoadjuvant therapy were also associated with higher numbers of involved nodes and higher pretreatment T stage when compared to cases with TDs but without neoadjuvant therapy.
Category: Gastrointestinal

Monday, February 28, 2011 9:15 AM

Platform Session: Section E, Monday Morning

 

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