Mouth to pouch transit after restorative proctocolectomy: hydrogen breath analysis correlates with scintigraphy.

OBJECTIVES: Fast intestinal transit may be responsible for slow adaptation and unacceptable steady-state function after restorative proctocolectomy. Investigation of GI transit time may be valuable in such a setting. We hypothesized that postprandial hydrogen breath tests may yield transit data that correlate with technetium-labeled meal scintigrams. METHODS: This study compared intestinal transit after a lactulose and bean meal via the breath hydrogen and scintigraphy methods in 21 ileoanal pouch subjects. The meal consisted of baked beans (425 g), 30 ml (20 g) lactulose syrup, 1 mCi 99mtechnetium sulfur colloid in finely chopped liver and 170 ml tap water. The meal contained 120 Kcal (70% carbohydrate, 18% protein and 12% fat). RESULTS: Of 21 pouch subjects, 11 (53%) had breath tests and scintigraphy transit studies that differed by 5-21 min. Three of 21 (14%) scintigraphy mouth to pouch transit times were faster than breath test transits by 43-107 min. Seven of 21 (33%) subjects did not have breath test peaks >10 ppm. Mouth to pouch transit for breath hydrogen (104+/-16 min) and scintigraphy (98+/-7 min) tests had significant correlation (r = 0.96, p < 0.0001) among subjects with alveolar hydrogen peaks and accurate scintigrams (n = 11). Scintigrams were five times more expensive than breath tests. CONCLUSIONS: A peaking hydrogen breath test provides an alternative to scintigraphy for estimating intestinal transit after ileoanal pouch.

Influence of arginine dietary supplementation on healing colonic anastomosis in the rat.

INTRODUCTION: This study sought to determine whether dietary arginine influences colonic anastomotic healing in the rat model. METHODS: Three groups of 42 Sprague-Dawley rats were fed 0, 1, and 3 percent arginine diets for three preoperative and three postoperative days. Animals underwent transection of the transverse colon with hand-sewn anastomosis. Subgroups of 14 animals in each dietary group were killed on postoperative Days 6, 10, or 14, and bursting pressures, histologic inflammation, and collagen content were compared. RESULTS: Mean anastomotic bursting pressures on postoperative Day 6 were lower for the 0 percent arginine group than the 1 and 3 percent arginine groups (mean +/- standard error of the mean = 134+/-6 mm Hg, 164+/-7 mm Hg, and 166+/-7 mm Hg, respectively; P<0.0005). On Days 10 and 14, no significant differences in bursting pressures were noted between arginine diets. Mean bursting pressures on postoperative Day 6 (155+/-4 mm Hg) were significantly lower than on Days 10 (204+/-5 mm Hg) and 14 (217+/-6 mm Hg; P<0.001) for all arginine diets. Microscopic evaluation of the anastomoses did not show significant differences in inflammation or collagen content between arginine diets. Collagen content in all dietary groups peaked at Day 10. CONCLUSIONS: Perioperative arginine deficiency in the rat model is associated with impaired anastomotic healing during the first week, as reflected by lower bursting pressures. Arginine supplementation to 3 percent does not improve bursting pressures above those found in the usual 1 percent arginine diet at 6, 10, or 14 days. Bursting pressures plateau by Day 10 regardless of perioperative dietary arginine, whereas collagen content peaks at Day 10 after six-day perioperative arginine diet manipulation.

Preoperative chemoradiation downstages locally advanced ultrasound-staged rectal cancer.

BACKGROUND: This prospective study assessed the effect of preoperative radiation and chemotherapy on the pathologic staging of advanced rectal cancer. METHODS: Twenty patients with rectal cancer were treated with combined chemoradiation prior to operation, after pretreatment staging of all lesions with transrectal ultrasound (TRUS). Perirectal fat invasion served as minimal criteria for preoperative neoadjuvant therapy. The pretreatment stage of these rectal lesions as defined by TRUS was then compared with the pathological stage of the surgical specimen following resection. Cancers were treated with high-dose radiation (45 to 54 Gy) in 19 of 20 patients. One patient received in excess of 60 Gy because of tumor characteristics. Chemotherapy consisted of 5-fluorouracil delivered as a continuous infusion or bolus therapy. Four to 8 weeks after neoadjuvant therapy, 13 abdominal perineal resections, 5 low anterior resections, and 2 completion proctectomies were performed. RESULTS: Following resection, rectal cancer was downstaged in 14 of 20 patients. No tumor was present in the rectal wall in 8 of 20 patients. Complete pathological response was present in 7 of 20 patients. Local recurrence occurred in 2 of 20 patients. Disease-free survival in the remaining 17 of 20 patients ranges from 9 to 51 months (average 26). CONCLUSIONS: Preoperative chemoradiation in the surgical management of advanced rectal cancer results in demonstrable tumor downstaging.

Metachronous colorectal cancer. Time interval to presentation of a metachronous cancer.

A retrospective review of 1888 colorectal cancer patients demonstrated 37 metachronous cancers in 30 patients for a metachronous cancer rate of 1.6 percent. Evaluation of the index cancers consisted of the traditional single-contrast barium enema and proctoscopic evaluation. Forty percent of the metachronous cancers appeared within two years of the index cancer. If the minimum length of the polyp-cancer sequence is three to five years, then this represents a failure of a traditional preoperative evaluation. A more sensitive evaluation potentially could decrease the metachronous cancer rate. Colonoscopy, which has been found to be more accurate in detecting synchronous neoplasms, should be included in the evaluation of all patients with colorectal cancers.

The role of colonoscopy in the assessment of patients with colorectal cancer.

A retrospective review of 176 patients with adenocarcinoma of the colon who underwent total colonoscopy preoperatively demonstrated synchronous carcinomas in 3.4 percent and synchronous polyps in 55.1 percent. Full-column barium enemas (68 patients) failed to identify cancer in 22 percent of patients and synchronous polyps in 58 percent of patients, a statistically significant (P less than 0.001) number of false-negative examinations. Double-contrast barium enemas (30 patients) failed to identify cancer in 27 percent of patients and synchronous polyps in 42 percent of patients, also a statistically significant (P less than 0.007) number of false-negative examinations. Full column and air contrast barium enemas identified all index cancers with distant metastases. Air-contrast barium enemas failed to identify 40 percent of "early" index cancers (confined to the bowel wall, negative nodes), and full-column barium enemas failed to identify 32 percent. The incidence of synchronous carcinoma and polyps underscores the need for total colon evaluation when a primary carcinoma is detected. Because of the poor accuracy of barium studies, total colonoscopy is the method of choice for this evaluation.