Large bowel carcinoid tumors.

PURPOSE OF REVIEW

Gastrointestinal carcinoids comprise 90% of all carcinoid tumors and all carcinoids have malignant potential. This review focuses on the morphology, prognosis, detection and treatment for appendiceal, colonic and rectal carcinoids.

RECENT FINDINGS

Computed tomography exists as an initial examination for the primary carcinoid tumor as well as for metastases. There have, however, been recent developments of newer and more accurate modalities. Octreotide scanning has a sensitivity of primary tumor detection of 90%; additionally, I- or I-meta-iodobenzylguanidine scanning and tracer-specific positron emission tomographic scans have demonstrated encouraging results. Further advancements in treatment with tumor-targeted therapy and biochemical evaluation of carcinoids have shown promise.

SUMMARY

The recent progress with scintigraphic and radiologic modalities has provided better means for diagnosis of primary and metastatic carcinoid tumors. These newly discovered diagnostic modalities have been more encouraging than the recent treatment approaches that have been studied with regard to metastatic carcinoids. While surgery remains the mainstay of treatment of nonmetastatic carcinoid, there have been studies for various medical treatments of metastatic disease. Unfortunately, there have been disappointing results with regard to improvement of tumor response and patient survival, but a foundation has been established for future trials employing alternative agents and exploration of combination therapies.