Neugut and colleagues have compiled a very comprehensive, thoughtful description of the incidence, epidemiology, etiology, clinical presentation, and treatment of small bowel malignancies. This is a very unusual tumor that few clinicians will encounter during their careers, and fewer still will diagnose preoperatively.
I certainly concur with the authors' statement that surgical intervention provides the only hope of cure for these patients. I disagree, however, that small bowel tumors are unresectable when there are metastases to regional lymph nodes. In general, patients with small intestinal adenocarcinomas are managed with aggressive regional mesenteric lymphadenectomy, even when the nodes are clinically negative. Survival among patients with positive nodes is certainly seen in this disease. The local criteria of unresectability include involvement of central, as opposed to peripheral, mesenteric vessels.
Role of Radiation Therapy
With regard to the role of radiation therapy, one of the reasons that it is inappropriate relates to the mobility of the small bowel; this mobility makes it exceedingly difficult to define a treatment field. In theory, what is appealing about intraoperative radiation therapy is its ability to define a field at risk for locoregional recurrence while at the same time excluding adjacent viscera from that field.
Finally, with respect to the appropriate treatment of duodenal adenocarcinoma, it is extremely difficult in small retrospective series to separate the impact of treatment from that of patient selection. One would expect that patients with unresectable disease treated with chemotherapy and/or radiation therapy would have more advanced disease, and thus, would not do as well as those who are potentially resectable with pancreaticoduodenectomy. I agree with the authors that the extent of surgical resection is not a uniform predictor of improved outcome.
The authors are to be commended for very succinctly summarizing the current state of knowledge about this unusual tumor. They have emphasized the frustration we all feel in dealing with unusual malignancies: Given the nearly insurmountable difficulties in mounting large cooperative prospective trials, we are unlikely to know much more about the biology or treatment of there "orphan diseases" 10 years from now.
A 70-year-old man with a history of localized prostate cancer treated with whole-pelvis radiation therapy with a boost to the prostate, in conjunction with androgen deprivation therapy 7 years prior, presented with lower back pain. A bone scan revealed an area of activity in the sacrum. What is the most likely diagnosis?
