[708] Proposal for a More Applicable and Clinically Relevant Staging Evaluation of Ampullary Carcinomas.

Takuma Tajiri, Nobu Ohike, Serdar Balci, Grace E Kim, Alyssa Krasinskas, Olca Basturk, Nevra Dursun, Michael Goodman, David Kooby, Shishir Maithel, Juan Sarmiento, Charles Staley, NVolkan Adsay. Showa University, Yokohama, Japan; Emory University, Atlanta, GA; UCSF, San Francisco, CA; UPMC, Pittsburgh, PA; MSKCC, NY

Background: Due to its anatomic complexity and lack of uniform definitions, staging of ampullary carcinomas (ACs) is highly problematic, as evidenced by the survival data provided within the AJCC-2010 manual, which shows reverse prognosis for T1 vs T2. Since ACs tend to have a large preinvasive component, the importance of size of the invasive component may have been underestimated.
Design: A revised staging system was devised by 1) modifying the problematic aspects of T-stage, and 2) by incorporating invasion size (i-size). Since the current distinction between AJCC T1 vs T2 is highly subjective and sampling-protocol dependent, we classified these early tumors confined to muscle (Oddi/duodenal musculature complex) based on size: T1, < 1 cm and T2, ≥ 1 cm. We defined T3 as spread beyond the muscles into either the periduodenal soft tissue (at the groove area) or < 0.5 cm into the pancreas, and/or i-size of ≥ 2 cm but < 4 cm. T4 was defined as invasion (perforation) of duodenal serosa, deep (> 0.5 cm) invasion into the pancreas, and/or i-size ≥ 4 cm. This staging scheme was tested in 249 well-characterized and strictly defined ACs.
Results: The AJCC stage rendered in the original pathology report was different than the AJCC stage assigned in our study in 37% of the cases, highlighting the challenges in employing AJCC, while our proposed staging system was applied with relative ease, regardless of sampling protocol. Moreover, our proposed system has strong prognostic value (p<0.0001; Fig.1).


Conclusions: Current AJCC-2010 T-staging of ACs is difficult to apply and prognostically irrelevant. Our modified stage is relatively simple for practicing pathologists to use, circumvents anatomic complexities of the region and the corresponding sampling protocol differences, and incorporates biologic characteristics of ACs. Most importantly, it has very strong prognostic value.
Category: Gastrointestinal

Tuesday, March 1, 2011 11:45 AM

Platform Session: Section E, Tuesday Morning

 

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