Adjuvant intraoperative post-dissectional tumor bed chemotherapy-A novel approach in treating midgut neuroendocrine tumors.

ABSTRACT

BACKGROUND: Midgut neuroendocrine tumor (NET) patients are often diagnosed at an advanced stage with extensive mesenteric lymph node and liver metastasis. Even with skillful surgical dissection, macro and microscopic residual disease at the dissection site remains a possibility. We hypothesize these potential tumor residuals in mesenteric lymph node dissection beds can be eliminated safely by a local application of 5-fluorouracil (5-FU). We describe a novel technique invented by the author to treat these micro and macro residuals. METHODS: Retrospectively, charts of 62 consecutive midgut NET patients with boggy mesenteric lymphadenopathy who underwent cytoreductive debulking surgeries from 1/2007 to 12/2009 were reviewed. A total of 32 patients received an intraoperative application of 5-FU saturated gelfoam strips secured into the mesenteric defect following the extensive lymphadenectomy. A total of 30 untreated patients served as a control. RESULTS: The 5-year survival after cytoreductive surgeries was 22/32 (68.8%) for the treated group, vs. 20/30 (66.7%) for the control. Six patients (6/32, 18.8%) among the study group required additional debulking surgeries, vs. 16 patients (16/30, 53.3%) in the control group. Upon reoperation, loco-regional recurrence was noted in 9 of the 16 patients (56.3%) in the control group, vs. only 2/6 (33.3%) of treated patients. Overall, local recurrence rate is 6.25% (2/32) in the treated group vs. 30% (9/30) in the control group. Post-op complication rates are similar in the two arms. CONCLUSIONS: Intraoperative application of chemotherapy is a safe and effective adjuvant to reduce local recurrence and the need of reoperation by the tumoricidal or tumorstatic effects of 5-FU on any potential microscopic residual disease after extensive cytoreductive surgeries in advanced stage NET patients with mesenteric lymph node metastasis. It provides patients with sustained, slow releasing, high dose of 5-FU within the surgical bed with a negligible side effect profile. Further studies are required to evaluate its effect on long term survival.