Localized high-grade gastroenteropancreatic neuroendocrine tumors: Defining prognostic and therapeutic factors for a disease of increasing clinical significance

BACKGROUND

Due to the limited sample size in the existing series, the natural history and management of high-grade gastroenteropancreatic neuroendocrine tumors (GEP-NET) is poorly understood. In order to better understand high-grade GEP-NET, a large cohort study was undertaken.

OBJECTIVE

To determine the prognostic factors associated with high-grade GEP-NET.

METHODS

Patients diagnosed with non-metastatic high-grade GEP-NET from 1988 to 2010 were identified in SEER.

RESULTS

Incidence of high-grade GEP-NETs increased from 0.03 to 0.19/100,000 over the study period. The median age was 65 years, and the majority of the patients were white and females. The most common primary site was colorectal, and the most frequent T classification was T3. Surgical resection was performed in 89% of patients that varied by site (p < 0.0001). Nodal involvement was frequent and varied by site (p = 0.0002). The 5-year disease-specific survival was 63.3% and was the greatest for small bowel (p = 0.0003). Survival was associated with age, node status and surgery (p < 0.05). On multivariate analysis, the node status, surgery, and site continued to be associated with survival (p < 0.05); however, age (p = 0.08) no longer influenced the patient's survival.

CONCLUSION

High-grade GEP-NETs are neoplasms with exponentially increasing in incidence. Tumor location and nodal status are predictors of survival. Surgery is associated with a survival advantage and could be considered for localized disease.

Pushing the envelope beyond a centimeter in rectal cancer: Oncologic implications of close but negative margins

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Background: Advances in surgery, adjuvant therapy and understanding of the natural history of rectal cancer has enabled sphincter preservation surgery for most patients. A 1 cm margin is commonly accepted as minimal distal margin, when not achievable many are relegated to permanent colostomy. Our purpose was to determine if distal margins of < 1 cm is justified by the world's published experience.

Methods: Studies were identified with a MEDLINE search using terms rectal cancer, colorectal cancer, margins and distal margins with an additional manual search. There were no restrictions on data type or year of publication. All studies were retrospective or prospective, none were randomized controlled. Studies were excluded if specific margins, local recurrence rates or case level data could not be extracted. Extracted variables included year of publication, time span, number of patients, standardized surgery, radiotherapy, margins, follow up, local recurrence rates and overall survival. Meta-analysis was performed using a random weighting scheme. Values were aggregated across studies to determine overall impact and p-values.

Results: Seventeen studies reported margins with thirteen studies, 3,232 patients, reporting outcomes when < 1cm. Meta-analysis of all studies indicated a nonsignificant trend favoring greater margins. However, in order to understand distal margins in the context of current standards additional analyses were performed. Of the thirteen studies 4 reported neither TME nor use adjuvant radiotherapy and 9 studies reported use of one or both. When either total mesorectal excision and/or adjuvant radiotherapy was reported there was no significant increase in local recurrence with distal margins < 1 cm. In studies that used neither therapy > 1 cm margins were statistically less prone to recurrence.

Conclusions: Sphincter preservation is possible with < 1 cm distal margin when optimal surgical and adjuvant therapy are applied.

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Betaine aldehyde dehydrogenase in plants

Plant betaine aldehyde dehydrogenases (BADHs) have been the target of substantial research, especially during the last 20 years. Initial characterisation of BADH as an enzyme involved in the production of glycine betaine (GB) has led to detailed studies of the role of BADH in the response of plants to abiotic stress in vivo, and the potential for transgenic expression of BADH to improve abiotic stress tolerance. These studies have, in turn, yielded significant information regarding BADH and GB function. Recent research has identified the potential for BADH as an antibiotic-free marker for selection of transgenic plants, and a major role for BADH in 2-acetyl-1-pyrroline-based fragrance associated with jasmine and basmati style aromatic rice varieties.

Ex vivo sentinel lymph node biopsy in colorectal cancer: a feasibility study

BACKGROUND AND OBJECTIVES

Sentinel lymph node (SLN) biopsy may improve staging of colorectal cancer. We tested the feasibility of ex vivo SLN dissection.

MATERIALS AND METHODS

Patients undergoing resection of a primary colorectal cancer were included in this study. SLN identification involved ex vivo injection of 1 cc isosulfan blue dye subserosally in the colon or submucosally in the rectum on a separate field. SLNs were cut at 2 mm intervals. Three hematoxylin and eosin-stained (HE) sections were prepared in addition to a middle level for cytokeratin immunostaining.

RESULTS

Twenty-six patients with varying tumor location and stage were enrolled and the SLN was identified in 88% (23/26) cases. Three failures occurred in patients with rectal cancer. The average number of SLN harvested was 2.5. The status of the nodal basin was accurately predicted in 91% (21/23) of patients. Two false negative sentinel lymph nodes were harvested in 2 of 3 patients with stage III/IV colorectal cancer. The SLN upstaged 2 patients as a result of HE stained step sections (n = 1) and immunostaining (n = 1).

CONCLUSIONS

This data suggests that ex vivo SLN biopsy is feasible in colorectal cancer. Although ex vivo SLN biopsy does not alter the lymphatic dissection, it may upstage a subset of patients. The ex vivo technique may be less applicable in rectal cancer and false negative results may occur.

Xenogeneic patch closure of the small intestine: a novel approach to fistula management

Previous work from our laboratory demonstrated the feasibility of utilizing placental-derived collagen tissue matrix (CTM) as a bowel wall substitute. We reasoned that this technique would also be suitable in managing intestinal fistulae. To test this hypothesis, we created a chronic cecal fistula in rats and randomly managed some with primary repair and others with CTM replacement. Leak rates, mortality, bursting pressures and histologic scores were similar, suggesting that a chronic fistula can be successfully managed with either a CTM or primary repair.