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EDITORIALS |
From the Roswell Park Cancer Institute, State University of New York at Buffalo, Buffalo, New York.
Correspondence: Address correspondence and reprint requests to: John F. Gibbs, MD, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263; Fax: 716-845-2320; e-mail: john.gibbs{at}roswellpark.org
Duodenal adenocarcinomas represent a unique, albeit uncommon, entity. Of the approximately 4800 cases of small bowel tumors encountered annually, the duodenum is the most commonly involved site (55%), followed by the jejunum (18%) and ileum (13%).1 Fourteen percent of patients have unspecified sites. The distribution pattern has been reported to parallel the relative length of each portion. Of tumors within the duodenum, 15% will involve the first portion, 40% the second portion, and 45% the third and fourth portions.2
The anatomic location of the duodenum within the gastrointestinal tract raises the question of whether duodenal adenocarcinoma that resembles gastric, pancreaticobiliary, or small bowel malignancies has its own distinct natural history. It has been suggested that the curious resistance of the small intestinal tract to the development of benign or malignant neoplasms, especially in comparison with the proximal (stomach) or distal (colon) sites within the gastrointestinal tract, is due to protective factors against carcinogen exposure and tumor development. In our experience patients have generally presented for evaluation late, after symptoms typically have been present for >3 months.3 Factors that have been shown to be associated with survival include histological grade, transmural involvement, tumor size, lymph node involvement, and distant metastases.4–7
The article by Sarela et al. in this issue of the Annals of Surgical Oncology is a well-written report of a large single-institution study by a well-recognized group, evaluating their 17-year experience with duodenal adenocarcinoma.8 The authors evaluate the importance of accurate lymph node staging in duodenal adenocarcinoma in comparison with antral gastric cancer. Complete resections (R0) were achieved in 72 and 331 patients with duodenal or antral gastric cancer, respectively (Table 1). The incidence of nodal positivity was similar in the two groups (43% and 47%, respectively). However the duodenal cancer group had fewer patients with 
15 lymph nodes assessed (47% vs. 64%). The group with 15 lymph nodes assessed compared favorably to the similar cohort from the antral gastric group. The authors conclude that for duodenal cancer, examination of 15 lymph nodes improved prognostic discrimination by the pN category.
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If one accepts the argument that duodenal and antral gastric cancer are similar in outcome and node positivity percentage rates, the difference reported in this study by Sarela et al. would be ascribed to total nodes assessed. This raises the age-old question concerning the accuracy of lymph node assessment and stage migration. It is unclear whether the authors advocate improved pathologic assessment or extended lymphadenectomy.
There is no argument that increased lymph node assessment invariably results in improved accuracy of staging.9 The lymphatic drainage pattern from each of the four portions of the duodenum and the total number of possible lymph nodes that can be expected to be retrieved are poorly understood.10 A recent report found a difference in the number of nodes retrieved between proximal (n = 6) and distal (n = 2) duodenal sites.5 The AJCC requires at least six regional lymph node assessments for duodenal or small bowel cancer.11 The lymph node stations that are routinely evaluated for duodenal adenocarcinoma include duodenum, hepatic, pancreaticoduodenal, infrapyloric, gastroduodenal, pyloric, superior mesenteric, pericholedochal, and regional lymph nodes not otherwise specified (NOS). Additionally, knowledge of the number of lymph nodes retrieved from the first/second-portion duodenal group (n = 56) in comparison with the third/fourth-portion duodenal group would have facilitated further examination of this study.
The authors do not report their pathologic technique in assessing resected duodenal adenocarcinoma lymph nodes. As stated in the article, total numbers of lymph nodes retrieved are greater in the proximal versus distal duodenum, because the former typically necessitates a standard pancreaticoduodenectomy, which includes the perigastric antral lymph nodes, whereas the distal portions of the duodenum are removed by segmental resection. Thus, the addition of antral lymph nodes may have swayed the study. We cannot glean from the study the total number of additional lymph nodes and the positivity rate contributed from this portion of the specimen.
The possibility of stage migration is appropriately introduced by Sarela et al. One would anticipate an improvement in disease-specific survival in both the node-negative and node-positive duodenal adenocarcinoma groups who have >15 nodes assessed. Indeed, Sarela et al. show a 25% improvement (75% to 100%) in survival when >15 lymph nodes are assessed in node-negative duodenal adenocarcinoma (Table 2).
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Duodenal adenocarcinoma remains a disease plagued by delayed diagnosis and poor outcome. Sarela et al. demonstrate that improved survival can be achieved for patients diagnosed early when they have no nodal involvement. The importance of total lymph node sampling remains unclear. Because the majority of duodenal cancers involve the first and second portion of the duodenum, which is treated by standard pancreaticoduodenectomy, the point may be mute.
The increased number of lymph nodes assessed by Sarela et al. appears to be due to the incorporation of perigastric antral lymph nodes. The study results seem to suggest a benefit for the subset of patients with early and proximal duodenal adenocarcinoma who undergo a standard pancreaticoduodenectomy with increased postoperative nodal assessment.
The authors do not provide a convincing argument to adapt a change from the AJCC recommendation. However, thorough lymph node assessment is important to identify patients at increased risk for recurrence who may benefit from enrollment in clinical trials involving novel approaches. Establishing the potential role of sentinel lymph biopsy may provide additional information.12
Received for publication February 13, 2004. Accepted for publication February 19, 2004.
REFERENCES
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