Discrepancy in the assessment of tumor response in patients with pancreatic cancer: WHO versus RECIST criteria

PURPOSE

The Response Evaluation Criteria in Solid Tumors (RECIST) have largely replaced the World Health Organization (WHO) criteria as a preferred method for assessing tumor response in clinical trials. We hypothesized that due to frequent asymmetric growth pattern, as well as somewhat diffuse margins of pancreatic cancer, the use of WHO vs. RECIST criteria may result in significantly different tumor response assessments. The purpose of this retrospective study was to compare the WHO (bidimensional) to RECIST (unidimensional) in assessing treatment response in pancreatic cancer patients enrolled in clinical trials.

MATERIALS AND METHODS

We have evaluated the contrast- enhanced computed tomography (CT) images from 12 pancreatic cancer patients with measurable disease enrolled in two phase I/II clinical trials at the Arizona Cancer Center, between July 2000 and July 2003. The tumor measurements were re-calculated by RECIST and WHO criteria and were compared.

RESULTS

In 3 out of the 12 patients (25%) there was discordant response categorization when WHO criteria were used instead of RECIST. Clinical presentations in all 3 patients were more consistent with WHO categorization.

CONCLUSION

Our retrospective data analysis suggests that use of different tumor response criteria (RECIST vs. WHO) may result in different assessments of treatment efficacy in patients with pancreatic cancer on clinical trials. This finding warrants further confirmation in a larger prospectively designed trial.

Correlation of gastroesophageal reflux disease symptoms characteristics with long-segment Barrett's esophagus

Thus far, there has been a paucity of studies that have assessed the value of the different gastroesophageal reflux disease (GERD) symptom characteristics in identifying patients with long-segment Barrett's esophagus versus those with short-segment Barrett's esophagus. To determine if any of the symptom characteristics of GERD correlates with long-segment Barrett's esophagus versus short-segment Barrett's esophagus. Patients seen in our Barrett's clinic were prospectively approached and recruited into the study. All patients underwent an endoscopy, validated GERD symptoms questionnaire and a personal interview. Of the 88 Barrett's esophagus patients enrolled into the study, 47 had short-segment Barrett's esophagus and 41 long-segment Barrett's esophagus. Patients with short-segment Barrett's esophagus reported significantly more daily heartburn symptoms (84.1%) than patients with long-segment Barrett's esophagus (63.2%, P = 0.02). There was a significant difference in reports of severe to very severe dysphagia in patients with long-segment Barrett's esophagus versus those with short-segment Barrett's esophagus (76.9%vs. 38.1%, P = 0.02). Longer duration in years of chest pain was the only symptom characteristic of gastroesophageal reflux disease associated with longer lengths of Barrett's mucosa. Reports of severe or very severe dysphagia were more common in long-segment Barrett's esophagus patients. Only longer duration of chest pain was correlated with longer lengths of Barrett's esophagus.

Non-erosive reflux disease (NERD)--acid reflux and symptom patterns

BACKGROUND

Recent reports suggest that patients with non-erosive reflux disease (NERD) treated with anti-reflux medications show lower symptom improvement rates than patients with erosive oesophagitis treated with the same medications.

AIM

To determine the acid reflux and symptom patterns of patients with NERD in comparison with those with erosive oesophagitis and Barrett's oesophagus, and to identify different NERD subgroups.

METHODS

One hundred and forty-nine consecutive patients seen for classic heartburn symptoms were evaluated for the study. Oesophageal mucosal injury was assessed by upper endoscopy and classified by Hetzel-Dent criteria. Patients with Hetzel-Dent grades 0-1 were considered to have NERD. The extent of oesophageal acid exposure was determined by ambulatory 24-h oesophageal pH monitoring.

RESULTS

Seventy-one patients were found to have NERD, 36 erosive oesophagitis and 42 Barrett's oesophagus. Compared with patients with erosive oesophagitis (75%) and Barrett's oesophagus (93%), those with NERD (45%) were significantly less likely to have an abnormal pH test (P = 0.0001). Patients with Barrett's oesophagus had the highest mean number of acid reflux events (210 +/- 17.7), compared with those with erosive oesophagitis (139.7 +/- 15.2) and NERD (95.3 +/- 9.4) (P = 0.0001); however, the rate of perceived acid reflux events was similar and very low in all groups (NERD, 3.6%; erosive oesophagitis, 2.9%; Barrett's oesophagus, 2.17%). NERD-positive patients (abnormal pH test) had a similar extent of oesophageal acid exposure to those with erosive oesophagitis. NERD-positive patients were more likely to demonstrate a symptom index greater than 75% than NERD-negative patients (normal pH test) (61.9% vs. 10.5%; P = 0.0001). In the NERD-negative group, those with a negative symptom index reported having heartburn at pH < 4 only 12.7% of the time, compared with 70.7% of the time in those with a positive symptom index, despite a similar mean number of heartburn episodes.

CONCLUSIONS

Patients with NERD commonly demonstrate a negative pH test. Acid reflux characteristics and symptom patterns suggest a heterogeneous group of patients.

Short segment Barrett's esophagus: relationship of age with extent of intestinal metaplasia

OBJECTIVE

Short segment Barrett's esophagus (SSBE) is defined by the presence of intestinal metaplasia in biopsies obtained from mucosa with an appearance suggestive of Barrett's that extends <3 cm into the esophagus. It has been suggested that this lesion may represent a stage in an ongoing process of Barrett's esophagus progression. If so, then the prevalence of SSBE would be expected to decrease with advancing age, and patients followed over time should exhibit an increase in the extent of columnar-lined esophagus. The aim of this study was to determine whether SSBE length progresses or regresses over time by following a prospective cohort and by assessing the relationship between age and the length, as well as prevalence of SSBE.

METHODS

The study included consecutive patients who were evaluated prospectively by an upper endoscopy and were found to have SSBE between October, 1983, and December, 1999, at the Southern Arizona VA Health Care System. All patients underwent a systematic biopsy protocol, and a designated pathologist who reviewed all specimens confirmed the diagnosis of Barrett's esophagus. Patients were subsequently interviewed for demographic information. In those patients who were enrolled into our surveillance program, SSBE length was remeasured and intestinal metaplasia reconfirmed on follow-up endoscopies.

RESULTS

Of 343 patients with endoscopically proven Barrett's esophagus, 116 (33.8%) were found to have SSBE. Almost all were male (97.4%) and white (85.3%), with a mean age of 60.1+/-1.0 yr. The prevalence of SSBE increased with age and reached a plateau during the seventh decade of life. One-way analysis of variance showed that there was no significant difference in the mean length of SSBE among the various age groups (p = 0.84). This trend was maintained when only the white group was assessed. Follow-up endoscopies were performed in 57 patients, revealing a mean interval of 64 months to the latest endoscopy, with no significant difference in SSBE length between the first and last endoscopy (p = 0.16).

CONCLUSIONS

The prevalence of SSBE increases with age until the seventh decade of life. Finding that SSBE length does not change across the various age groups and during a 64-month mean follow-up, suggests that SSBE does not progress over time.

Preferential repair by squamous epithelium of thermal induced injury to the proximal stomach in patients undergoing ablation of Barrett's esophagus

BACKGROUND

The presence of extensions of squamous epithelium into the proximal stomach in patients undergoing routine upper endoscopy has recently been described. The factors that may favor development of squamous epithelium within the proximal stomach remain unknown.

METHODS

Patients with Barrett's esophagus who agreed to undergo ablation of Barrett's epithelium by using multipolar electrocoagulation were included. Patients were treated with a high dose of a proton pump inhibitor. The columnar-appearing mucosa was systematically treated. Occasionally, thermal injury was inadvertently induced in the proximal stomach. On endoscopy performed 4 to 6 weeks after treatment, the presence of squamous epithelium extending into the proximal stomach was documented. The use of Lugol's stain assisted in confirming the squamous nature of the abnormal tissue, which was confirmed histologically by cytokeratin immunohistochemistry.

RESULTS

The 12 patients included in the study had a mean length of Barrett's epithelium of 3.8 +/- 0.7 cm. Patients were treated with omeprazole, mean dose 66 +/- 6.0 mg, and had a mean percent total time that the pH was less than 4 of 1.9 +/- 0.8. The mean length and width of gastric squamous extensions were 1.7 +/- 0.2 cm and 0.8 +/- 0.1 cm, respectively. None of the squamous extensions into the stomach were documented before mucosal ablation. The extensions stained positively for cytokeratin 13 and negatively for cytokeratin 8, thereby confirming their squamous nature.

CONCLUSIONS

Thermal injury to the proximal stomach in patients undergoing ablation of Barrett's epithelium and profound acid suppression results in repair by squamous epithelium. Recognition of this lesion is essential because it may lead to confusion as to the location of the esophagogastric junction in subsequent endoscopic evaluations.

Inability to noninvasively diagnose gastric intestinal metaplasia in Hispanics or reverse the lesion with Helicobacter pylori eradication

BACKGROUND

Helicobacter pylori infection has been linked with the development of gastric adenocarcinoma and its precursor lesion, intestinal metaplasia (IM). The presence of gastric IM is not associated with symptoms, which makes identification of individuals with this lesion difficult. It is not clear whether eradication of H. pylori infection leads to reversal of gastric IM or the potential decrease in the risk of cancer in these patients.

GOALS

The purpose of this pilot study was to define the prevalence of gastric IM in a population at high risk for gastric cancer (Southwestern Hispanics), examine the ability of noninvasive testing to identify individuals with the lesion, and determine whether eradication of H. pylori infection reverses gastric IM in this population.

STUDY

Subjects from the Tucson metropolitan area were recruited, and baseline data, including the presence of upper gastrointestinal (UGI) symptoms, urinary sodium, and serum pepsinogen levels, were obtained. Upper endoscopy was performed and six gastric biopsies from specific anatomic sites were obtained, followed by methylene blue staining with targeted biopsies from blue-stained mucosa. Biopsies were evaluated for the presence of H. pylori infection and gastric IM. A subset of patients with gastric IM were treated to eradicate H. pylori infection. Follow-up exams with methylene blue staining, including biopsies for histology and rapid urease testing, were performed for up to 48 months.

RESULTS

There were 84 subjects with a mean age of 53.0 years; 24 (29%) had gastric IM and 65 (77%) had H. pylori. There was no significant association between gastric IM and age, gender, UGI symptoms, H. pylori, or urine sodium. There was an association identified between gastric IM and a decreased pepsinogen I:II ratio (p = 0.03). Of the 11 individuals with gastric IM treated for H. pylori infection, 9 had successful therapy and underwent at least 2 follow-up examinations. The mean length of follow-up was 3.3 years. Eight of the nine (89%) had gastric IM identified histologically at the final endoscopic exam.

CONCLUSIONS

H. pylori infection and gastric IM are frequent findings in Southwestern Hispanics, a high-risk population for gastric cancer. Noninvasive testing is not clinically useful in distinguishing individuals within this group who harbor gastric IM. Although eradication of H. pylori infection may lead to a decrease in the amount of gastric IM in some individuals, the lesion may be detected in the majority of individuals after more than 3 years of follow-up. These data suggest that therapy for H. pylori may not eliminate the risk of gastric cancer once IM has developed.

Correlation of oesophageal acid exposure with Barrett's oesophagus length

BACKGROUND

Gastro-oesophageal reflux disease (GORD) plays a major role in the development of Barrett's oesophagus. However, it has yet to be elucidated what factors determine the length of Barrett's mucosa in each individual patient.

AIMS

To determine if there is a correlation between oesophageal acid exposure and the length of Barrett's mucosa. We also compared the extent of oesophageal acid exposure between patients with short segment (SSBE) and long segment (LSBE) Barrett's oesophagus.

METHODS

Twenty seven patients with Barrett's oesophagus were recruited prospectively into the study from the outpatient gastroenterology clinic at the Southern Arizona VA Health Care System. Diagnosis of Barrett's oesophagus and its anatomical characteristics were determined during upper endoscopy. Ambulatory 24 hour oesophageal pH monitoring assessed the extent of oesophageal acid exposure.

RESULTS

There was a significant correlation between per cent total time pH less than 4 and length of Barrett's mucosa (r=0.6234, p=0.0005). In addition, there was a significant correlation between per cent upright and supine time pH less than 4 and length of Barrett's mucosa (r=0.5847, p=0.0014 and r=0.6265 p=0.0006, respectively). Patients with SSBE had significantly less oesophageal acid exposure than patients with LSBE, in terms of both per cent total time and per cent supine time pH less than 4 (p<0.05).

CONCLUSIONS

The length of Barrett's mucosa correlated with the duration of oesophageal acid exposure. Patients with LSBE experienced significantly more oesophageal acid exposure than patients with SSBE. Duration of oesophageal acid exposure appears to be an important contributing factor in determining the length of Barrett's mucosa.

Recent developments in Barrett's esophagus

Barrett's esophagus is a precancerous condition in which the squamous esophageal epithelium is replaced by a columnar epithelium. Although different types of columnar epithelium have been described, the most frequently encountered is specialized columnar epithelium or intestinal metaplasia. Most investigators believe that increased cancer risk is only associated with this type. Esophageal adenocarcinoma is increasing in frequency in the United States and in Western Europe. Recent studies highlight the importance of gastroesophageal reflux disease in esophageal adenocarcinoma. Bile-acid reflux may also play a role. Increasing interest has been expressed in short-segment (2-3 cm) Barrett's esophagus. The contribution of short-segment Barrett's esophagus to cancer at the gastroesophageal junction is currently being studied. Although regular surveillance is often recommended, the commonness of Barrett's esophagus makes such a practice impractical for every patient. Biomarker development is needed to identify patients at greatest risk, with p53 a promising candidate based on recent studies. Initial data suggest that redox mechanisms may be involved in Barrett's esophagus. Several methods have recently been described for reversing Barrett's esophagus to squamous epithelium, but the significance of this practice in terms of reducing cancer risk remains to be demonstrated.

Failure of oesophageal acid control in candidates for Barrett's oesophagus reversal on a very high dose of proton pump inhibitor

BACKGROUND

Normalization of oesophageal acid exposure using high dose proton pump inhibitors in patients who are candidates for ablation therapy has been suggested to be essential for successful Barrett's reversal. However, the success rate for achieving pH normalization has not been determined.

METHODS

Patients with Barrett's oesophagus (2-6 cm in length) who were found to be eligible for ablation therapy using multipolar electrocoagulation were included in this prospective study. Patients underwent an upper endoscopy to determine Barrett's length and other anatomic characteristics. Biopsies were obtained to rule out dysplasia. Subsequently, patients were treated with omeprazole 40 mg b.d. Twenty-four hour oesophageal pH monitoring was performed after a mean period of 8.4 +/- 0.6 days of therapy.

RESULTS

Twenty-five patients were enrolled into the study. The pH test was abnormal in four (16%) of the study subjects. An additional two (8%) patients had abnormal supine percentage time with pH less than 4. There was no significant difference in oesophageal acid control between patients with long vs. short segment Barrett's oesophagus. Elderly (> 60 years) patients tended to have less acid control than younger (</= 60 years) patients.

CONCLUSIONS

Failure of oesophageal acid control in candidates for Barrett's oesophagus reversal on very high dose of proton pump inhibitor is not uncommon. Our study suggests that ambulatory 24-h oesophageal pH monitoring should be considered in all candidates for Barrett's reversal who are treated with high dose proton pump inhibitor to ensure normalization of oesophageal acid exposure.

A collaborative end-of-life care curriculum

Death and dying in America has received limited attention in medical education. The Southern Arizona VA Health Care System and the University of Arizona have collaborated with three nonprofit community hospice programs to develop an end-of-life care curriculum. This formal and comprehensive program is offered as a one-month elective to senior medical students, residents and fellows. The goal of the program is to improve clinical skills in caring for the dying patient and foster research in palliative and supportive care.

Symptom severity and oesophageal chemosensitivity to acid in older and young patients with gastro-oesophageal reflux

INTRODUCTION

elderly patients appear to have a more aggressive form of gastro-oesophageal reflux disease than younger patients. Reduced pain perception with age is a possible underlying mechanism.

AIMS

to compare the extent of oesophageal mucosal injury, acid exposure, symptom severity and perception thresholds for acid infusion in older (aged 60 or older) and younger patients with gastro-oesophageal reflux.

METHODS

twenty-five younger and 23 older patients completed the study. We determined acid exposure and oesophageal mucosal injury by ambulatory 24-h oesophageal pH monitoring and upper endoscopy, respectively. We determined chemosensitivity by infusing 0.1 N hydrochloric acid into the mid-oesophagus for 10 min at 10 ml/min after a 2-min infusion of normal saline at a similar rate. We quantified acid perception thresholds by the lag time to initial typical symptom perception, intensity rating at the end of acid infusion and an acid perfusion sensitivity score, calculated from the fractional duration of symptom perception and intensity rating.

RESULTS

mean percentage of total time with pH <4 was higher in the older (15.8+/-2.4) than in the younger patients (11.9+/-1.8; P = 0.18). Of the older group, 74% had erosive oesophagitis versus 64% in the younger group. Frequency of symptoms (heartburn, acid regurgitation and dysphagia) was lower in the elderly group. Older patients perceived heartburn and acid regurgitation as much less severe than younger patients (P < 0.05).Younger patients had a significantly shorter lag time to initial symptom perception (P < 0.05) and a higher sensory intensity rating (P < 0.08). The acid perfusion sensitivity score was significantly lower in the older group (P < 0.05).

CONCLUSIONS

older patients with gastro-oesophageal reflux disease have reduced symptom severity for heartburn despite a tendency towards increased severity of oesophageal mucosal injury and acid exposure. Age-related reduction in chemosensitivity to acid is a possible underlying mechanism.

Beta-carotene produces sustained remissions in patients with oral leukoplakia: results of a multicenter prospective trial

BACKGROUND

Beta-Carotene has been reported to produce regressions in patients with oral leukoplakia, a premalignant lesion. However, previous studies have all been of short duration, with clinical response as the end point.

OBJECTIVE

To evaluate the duration of response and the need for maintenance therapy in subjects who respond to beta-carotene.

METHODS

In this multicenter, double-blind, placebo-controlled trial, subjects were given beta-carotene, 60 mg/d, for 6 months. At 6 months, responders were randomized to continue beta-carotene or placebo therapy for 12 additional months.

RESULTS

Fifty-four subjects were enrolled in the trial, with 50 being evaluable. At 6 months, 26 subjects (52%) had a clinical response. Twenty-three of the 26 responders completed the second, randomized phase. Only 2 (18%) of 11 in the beta-carotene arm and 2 (17%) of 12 in the placebo arm relapsed. Baseline biopsies were performed in all patients, with dysplasia being present in 19 (38%) of the 50 evaluable patients. A second biopsy was obtained at 6 months in 23 subjects who consented to this procedure. There was improvement of at least 1 grade of dysplasia in 9 (39%), with no change in 14 (61%). Nutritional intake was assessed using food frequency questionnaires. There was no change in carotenoid intake during the trial. Responders had a lower intake of dietary fiber, fruits, folate, and vitamin E supplements than did nonresponders. Beta-carotene levels were measured in plasma and oral cavity cells. Marked increases occurred during the 6-month induction. However, baseline levels were not restored in subjects taking placebo for 6 to 9 months after discontinuation of beta-carotene therapy.

CONCLUSIONS

The activity of beta-carotene in patients with oral leukoplakia was confirmed. The responses produced were durable for 1 year.

Durability of new squamous epithelium after endoscopic reversal of Barrett's esophagus

BACKGROUND

Endoscopic reversal of Barrett's esophagus with multipolar electrocoagulation and high-dose omeprazole has been previously described but long-term results are not available. The aim of this study was to follow patients after endoscopic reversal and to perform a detailed analysis of the "new" squamous mucosa.

METHODS

After reversal, patients with Barrett's esophagus were maintained on high-dose omeprazole and underwent interval endoscopy, and large biopsies were obtained of the former Barrett's epithelium.

RESULTS

Nine of 11 patients were men; the mean age was 62 years. The mean length of Barrett's mucosa was 4.4 cm; the mean dose of omeprazole used was 49 mg/day. All patients had an initial complete response to treatment-no evidence of Barrett's endoscopically and histologically. Three patients had intestinal metaplasia underlying the new squamous mucosa in the latest follow-up biopsies. In these 3 patients, only 0.4%, 2%, and 8% of the total biopsy area had intestinal metaplasia. All but 4 patients had underlying intestinal metaplasia at variable times during the study period. Patients have been followed for a mean of 36 months (range 19 to 53 months).

CONCLUSIONS

New squamous mucosa is durable and resembles normal squamous tissue. Underlying glands of intestinal metaplasia are intermittently found. Because the significance of this residual intestinal metaplasia is unclear, surveillance endoscopy with biopsies of the treated segment is recommended even after reversal therapy.

Alpha-tocopherol supplementation for men with existing coronary artery disease: a feasibility study

BACKGROUND

Recent studies have suggested that alpha-tocopherol supplementation can help reduce the incidence of coronary disease. Our objectives were to determine the feasibility of providing alpha-tocopherol supplements to male veterans with existing coronary artery disease and determine its effects on alpha-tocopherol levels and the susceptibility of low-density lipoprotein (LDL) to oxidation.

METHODS

Fifty-seven percent of 138 coronary disease patients were willing to participate in a placebo-controlled trial -25% were already taking antioxidants. Thirty-nine men were randomly assigned to either 400 mg/day of alpha-tocopherol (n = 27) or placebo (n = 12). alpha-Tocopherol levels and LDL oxidation (measured by formation of thiobarbituric acid-reactive substance) were measured at baseline and at 6 months.

RESULTS

Thirty-three subjects (22 alpha-tocopherol, 11 placebo) completed the study; 3 subjects withdrew after suffering coronary disease events. Supplement compliance exceeded 90% and alpha-tocopherol was well tolerated. The alpha-tocopherol group had a significantly greater mean increase in lipid-adjusted alpha-tocopherol levels (73% vs. -4.6%, P < 0.0001), but oxidized LDL did not change significantly.

CONCLUSIONS

A secondary prevention trial among veterans would be feasible because the rates of enrollment, completion, compliance, and clinical events were high. alpha-Tocopherol supplements did not decrease the susceptibility of LDL to oxidation, suggesting that higher dosages or longer duration of supplementation may be required for secondary prevention.

Effect of vitamin E on exhaled ethane in cigarette smokers

STUDY OBJECTIVES

We hypothesized that micronutrient antioxidant intake may be one factor determining the development of significant COPD. Vitamin E was administered to smokers to determine if exhaled ethane was reduced and if ethane correlated with measures of lung function.

STUDY DESIGN

Longitudinal placebo lead-in trial with posttreatment observation period.

SETTING

Tucson Veterans Affairs Medical Center.

PARTICIPANTS

Twenty-nine current stable smokers having no interest in smoking cessation.

INTERVENTIONS

Spirometry, exhaled breath ethane measurements, and vitamin E and [-carotene plasma levels followed by 3 weeks of placebo with repeat plasma vitamin levels and ethane measurements; next, 3 weeks of vitamin E (dl-a-tocopherol), 400 IU po bid followed by plasma vitamin levels and breath ethane measurements; finally, 3 weeks without vitamins followed by breath ethane and plasma vitamin levels.

RESULTS

Vitamin E treatment did not reduce ethane significantly. Exhaled ethane levels (mean + SD: pm/min/kg) were as follows: baseline, 7.39 + 5.39; after run-in period, 6.86 + 4.09; after vitamin E, 6.36+/-3.02; and final, 7.23+/-4.63. After vitamin E therapy, a significant negative correlation existed between exhaled ethane and FEV1/FVC. Pack-years of smoking at baseline and after vitamin E were significantly associated with ethane exhaled. Initial lung function was not significantly negatively associated with vitamin E-induced changes in exhaled ethane but a negative trend was found.

CONCLUSIONS

Vitamin E alone, unlike the combination of vitamins C, E, and beta-carotene, failed to reduced exhaled ethane in cigarette smokers. Exhaled ethane was correlated with pack-years of smoking. Smokers whose ethane values were found to fall the most tended to have better preserved lung function.

Squamous islands in Barrett's esophagus: what lies underneath?

OBJECTIVE

Squamous islands are frequently visualized at the time of upper endoscopy in patients with Barrett's esophagus, especially those on proton pump inhibitor therapy (PPI). The significance of these islands is not clearly understood. The aim of this study was to systematically biopsy macroscopic squamous islands and to examine their histologic characteristics.

METHODS

Patients with Barrett's esophagus undergoing surveillance had squamous islands documented and biopsied at the time of endoscopy. Barrett's esophagus was defined as the presence of a columnar lined esophagus on endoscopy with intestinal metaplasia on biopsy. All biopsies were obtained by a single senior endoscopist and were stained with alcian blue at pH 2.5. Biopsy samples with inadequate tissue quantity were not included in the study.

RESULTS

A total of 39 biopsies were obtained from 22 patients. Twenty of the 22 patients were male, with a mean age of 65.4 yr (range 47-80 yr). The mean length of Barrett's mucosa was 5.6 cm (range 1-11 cm). Eleven of 22 patients were on omeprazole (mean dose 29.1 mg/day), whereas seven patients were on lansoprazole (60 mg/day). The mean duration of PPI therapy was 2.3 yr (range 9-71 months) at the time of biopsy of the squamous islands. Three patients were on H2-blocker therapy whereas the remaining patient had not been started on acid suppression therapy. On histology, 24 biopsy specimens (61.5%) revealed only squamous epithelium, whereas 15 (38.5%) showed the presence of intestinal metaplasia underlying the squamous epithelium. There was no significant difference between the patients with and without underlying intestinal metaplasia in regard to age, Barrett's length, dose, and duration of PPI therapy.

CONCLUSION

In more than one-third of biopsies of macroscopic squamous islands within Barrett's esophagus, microscopic intestinal metaplasia is detected. The presence of squamous islands should not be equated with regression of Barrett's esophagus or with decreased cancer risk.

Dysplasia in short-segment Barrett's esophagus: a prospective 3-year follow-up

OBJECTIVE

Short segments of intestinal metaplasia in the distal esophagus are being recognized with increasing frequency. Both long and short segments of Barrett's esophagus can progress to dysplasia and cancer. However, the risk of short-segment Barrett's esophagus (SSBE) for the development of dysplasia and adenocarcinoma of the esophagus is not yet known. Our purpose, therefore, was to determine the frequency with which dysplasia occurs in patients with SSBE.

METHODS

Patients with SSBE were followed prospectively for the development of dysplasia. SSBE was defined as <3 cm of Barrett's-appearing epithelium above the gastroesophageal junction at endoscopy, with intestinal metaplasia on biopsy as documented by alcian blue stain at pH 2.5 on at least two endoscopic biopsies 6 months apart. Patients had interval upper endoscopy with systematic biopsy of the Barrett's segment.

RESULTS

Fifty-nine SSBE patients were identified. The mean length of Barrett's mucosa was 1.5 +/- 0.1 cm; the mean age of the patients was 63.1 +/- 1.3 yr. Five patients had low-grade dysplasia (LGD) at initial endoscopy, for a prevalence of 8.5%; none had high grade dysplasia (HGD). Thirty-two patients had follow-up endoscopy over a mean period of 36.9 +/- 5.4 months. Five of these patients developed dysplasia on follow-up, three with LGD and two with HGD, the incidence of any dysplasia being 5.7% per year. One patient with HGD that developed during surveillance progressed to adenocarcinoma of the esophagus over a 2-yr period. The other patient with HGD had LGD on follow-up endoscopy. Six patients with initial LGD had no evidence of dysplasia on follow-up.

CONCLUSIONS

The prevalence of dysplasia was 8.5% with an incidence of 5.7% per year in this group of SSBE patients, followed prospectively. Although dysplastic changes may not be identified on follow-up examination, some patients progress to adenocarcinoma. Therefore, we recommend surveillance endoscopy and biopsy in patients with SSBE just as in those with long-segment Barrett's esophagus.

Increased esophageal chemoreceptor sensitivity to acid in patients after successful reversal of Barrett's esophagus

When compared to patients with erosive esophagitis, patients with Barrett's esophagus have demonstrated reduced chemo- and mechanoreceptor sensitivity to acid infusion and balloon distension, respectively. However, anecdotal clinical experience suggested an increase in symptom perception in patients after successful elimination of Barrett's epithelium, using multipolar electrocoagulation (MPEC) and high-dose proton pump inhibitor (PPI). To determine perception thresholds to acid infusion, we evaluated eight consecutive patients after a series of MPEC treatments resulted in complete elimination of Barrett's mucosa and compared them to 10 age-matched patients with nonreversed Barrett's esophagus and 10 patients with symptomatic, endoscopy-documented erosive esophagitis (Hetzel-Dent grade 2 or greater). Chemosensitivity was determined by a modified acid perfusion test, where acid perception thresholds were quantified by the lag time to initial typical symptom perception, sensory intensity rating, and an acid perfusion sensory score (APSS). While patients after successful elimination of Barrett's esophagus had similar sensory intensity ratings and APSS as patients with erosive esophagitis, the lag times differed significantly between the groups, and both groups had significantly higher sensory intensity ratings and APSS than patients with nonreversed Barrett's esophagus. In conclusion, patients after complete reversal of Barrett's mucosa are unexpectedly as sensitive to acid as symptomatic patients with erosive esophagitis.

Lack of spontaneous regression of tubular adenomas in two years of follow-up

OBJECTIVE

Change in colon polyp size over time has not been well characterized. It has been inferred that some polyps will increase in size, leading to an increased risk of progressing to cancer, whereas other polyps may spontaneously regress. To develop a better understanding of the natural history of colon polyps, we prospectively investigated change in polyp size over a 2-yr period.

METHODS

Patients were enrolled if they had an endoscopically detected proximal rectal or sigmoid polyp measuring 3-9 mm. The index polyp site was then permanently marked with an adjacent India ink tattoo to allow definitive future localization of the polyp. Patients underwent flexible sigmoidoscopy at 6-month intervals, and at each examination, the polyp size was carefully measured with open biopsy forceps. After a maximum of 2 yr, each polyp was removed and the histology determined.

RESULTS

Thirty polyps were followed in 26 patients who completed the study. Twelve polyps were tubular adenomas (TA), one was tubulovillous, 14 were hyperplastic polyps (HP), two had no pathological diagnosis, and one was a leiomyoma. HP were more likely to decrease in size than were TA. Three polyps demonstrated fast growth rates (2-4 mm/yr), and all were TA. Two polyps were removed early because their size had reached 1 cm or more. Both of those polyps were TA. No polyps regressed completely during the 2 yr of the study; neither did we find consistent linear growth rates.

CONCLUSIONS

In contrast to prior reports, in this study, after polyps had been definitively localized with India ink, we observed no complete polyp regressions.

The incidence of adenocarcinoma in Barrett's esophagus: a prospective study of 170 patients followed 4.8 years

OBJECTIVES

Barrett's esophagus is a premalignant condition defined by the presence of intestinal metaplasia in the esophagus. Estimates of the incidence of adenocarcinoma developing in patients with Barrett's esophagus vary widely. We prospectively followed a cohort of patients to define the incidence.

METHODS

Between January 1982 and April 1995, all patients undergoing upper endoscopy at the VA Medical Center in Tucson, AZ, were surveyed for Barrett's esophagus. One hundred seventy-seven patients (174 males, three females) were found to have Barrett's esophagus. Seven of 177 were found to have adenocarcinoma either at initial endoscopy or within 6 months, resulting in a prevalence of 4%. One hundred seventy of 177 patients initially lacking cancer were available for systematic survey.

RESULTS

The mean age at the time of Barrett's diagnosis was 62 yr (range 30-85 yr). The mean follow-up period was 57 months or 4.8 yr (range 6-156 months), for a total of 834 patient-years. Adenocarcinoma developed in four patients, an incidence of 1/208 patient-years of follow-up.

CONCLUSIONS

The current series is larger and has a longer follow-up period than previous prospective trials and demonstrates a lower incidence of adenocarcinoma. Surveillance of patients with Barrett's esophagus for dysplasia remains an appropriate clinical practice.

Reversal of Barrett's esophagus with acid suppression and multipolar electrocoagulation: preliminary results

BACKGROUND

Barrett's esophagus is a premalignant lesion for esophageal adenocarcinoma. This study tests the hypothesis that re-injury of the metaplastic the epithelium in an acid-controlled environment will result in reversal of Barrett's to squamous epithelium.

METHODS

Patients with at least 2 cm of Barrett's esophagus were treated with omeprazole, and half the circumference of the Barrett's was treated with multipolar electrocoagulation (MPEC); the other half served as an internal control. After 6 months, the remaining Barrett's esophagus was treated with MPEC.

RESULTS

Twenty-four hour esophageal pH of less than 4 averaged 1.8% on a mean dose of 56 mg/day of omeprazole. Ten patients had visual and biopsy elimination of the targeted section of Barrett's esophagus after an average of 2.5 MPEC sessions. The remainder of the Barrett's esophagus is being treated in 9 patients; currently 5 have no evidence of Barrett's.

CONCLUSIONS

The combination of control of esophageal acid exposure and reinjury of the metaplastic epithelium reverses Barrett's esophagus to squamous epithelium as determined by endoscopy and biopsy.

Exhaled ethane and antioxidant vitamin supplements in active smokers

To determine the effect of nutritional agents on lipid peroxidation, 10 smokers were given 6 mg beta carotene, 200 IU vitamin E, and 250 mg vitamin C 4 times daily for 3 weeks. Lipid peroxidation was assessed by measuring baseline and postsupplementation levels of exhaled ethane. There was a 29% decrease in mean (+/-SD) exhaled ethane (4.06 +/- 1.49 vs 2.90 +/- 1.29 pmol.kg-1.min-1), with individual levels decreasing in 8 of the 10 smokers (p < 0.05, Wilcoxon sign rank test). Three nonsmokers had very low baseline levels of ethane that did not change with supplementation. Ethane production correlated with active (packs per day) and lifelong (pack-years) tobacco consumption. Also, a strong correlation was found between the decline in ethane output after micronutrient supplementation and the presupplement FEV1. Therefore, antioxidant vitamin supplementation resulted in attenuation of smoking-related lipid peroxidation, and the decreases in ethane production appears to be associated with preserved lung function.

Reproducibility of the measurement of colonic proliferation using bromodeoxyuridine across laboratories

Although measures of colonic cell proliferation are being used as potential intermediate markers in chemoprevention studies, measurement standardization is still ongoing. This study was designed to assess the reproducibility of the labeling index quantification, as measured by bromodeoxyuridine, across four laboratories experienced in its use. Each institution submitted 10 slides, with one circled area of each slide to be scored. Each site followed its standard procedures for scoring colonic crypts; no attempts to standardize these procedures were made. There was high concordance among the laboratories on whether scorable crypts were present on a particular slide, but only two pairs of laboratories demonstrated agreement statistically greater than that predicted by chance. The overall difference among the sites on the number of scorable crypts was marginally significant (P = 0.083), and there was a highly significant overall difference in the magnitude of the labeling index (P < 0.0001). Sites 1 and 2 tended to have similar results, as did sites 3 and 4, most likely due to common training. Even with these discrepancies, high correlation (r > 0.75) was observed among the reported labeling index values for each pair of laboratories. Without standardized training, these laboratories may differ in the crypts considered appropriate for counting and in whether cells are counted as labeled or unlabeled. These results suggest that standardized training in scoring across all sites performing labeling index determinations is required to assure reproducibility across sites or studies. These results may also help explain discrepancies in the average values of the labeling index reported in the literature.

Mutations of p53 in Barrett's esophagus and Barrett's cancer: a prospective study of ninety-eight cases

We had previously identified p53 mutations in Barrett's esophagus and therefore began a multiinstitutional study to determine their significance as a marker for malignancy. Ninety-eight patients from four institutions were studied. Forty-eight patients (37 men and 11 women, mean age 56.2 years) had Barrett's esophagus with metaplasia or dysplasia but no evidence of malignancy at a mean follow-up of 2.2 years. Barrett's esophagus was classified as metaplasia with no evidence of dysplasia in 32 patients, as low-grade dysplasia in 13, and as high-grade dysplasia in three. The other 50 patients (46 men and four women, mean age 60.2 years) had adenocarcinoma arising in Barrett's esophagus. Tissues from normal stomach or esophagus, tumor, and Barrett's esophagus were obtained for deoxyribonucleic acid analysis by endoscopic biopsy from patients with Barrett's esophagus or cancer or during operations on some patients with Barrett's cancer. Exons 5 through 9 of the p53 gene were studied for mutations by single-strand conformational polymorphism analysis after polymerase chain reaction amplification. Mutations detected by single-strand conformational polymorphism analysis were confirmed by deoxyribonucleic acid sequencing. None of the tissue samples from patients with Barrett's esophagus alone and no dysplasia or low-grade dysplasia had any p53 mutations, but one of the three patients with high-grade dysplasia and no evidence of invasive malignancy did have a p53 mutation. Of the 50 patients with Barrett's cancer, however, 23 (46%) had p53 mutations in Barrett's epithelium, tumors, or both. Twenty of these patients had p53 mutations in the tumor only (n = 16) or in both tumor and Barrett's epithelium (n = 4), suggesting that the mutation plays a direct role in carcinogenesis. Mutations in Barrett's epithelium were found in one patient in the group without malignancy and in seven patients with cancer (one with no dysplasia, two with low-grade dysplasia, and five with high-grade dysplasia). In three patients with cancer, mutations occurred only in Barrett's epithelium, suggesting that such mutations may also be a marker for genomic instability. Mutations were predominantly found in exons 5, 7, and 8, and transitions from guanine to adenine were the most frequent changes. Mutations of p53 are clearly involved in the pathogenesis of Barrett's cancer for a subset of patients (46%), and the fact that we could detect mutations in premalignant Barrett's epithelium supports the hypothesis that p53 mutations may be a useful marker for patients at increased risk for development of invasive cancer.

The difference in colon polyp size before and after removal

BACKGROUND

Accurate knowledge of polyp size is important in assessing cancer risk in both clinical studies and individual patients. We sought to determine if a difference exists between the endoscopic estimation of colon polyp size and the actual measurement after removal.

METHODS

We measured polyps in a systematic fashion. Using open biopsy forceps as a guide, the largest diameter of 31 pedunculated polyps was estimated endoscopically. The polyp was then removed by snare polypectomy and directly measured by a technician who was blinded to the endoscopic estimate. Each polyp was also measured after formalin fixation by a pathologist who was blinded to previous measurements.

RESULTS

There was a significant difference between the endoscopic estimates and the postpolypectomy measurements. Endoscopic estimates on average were 1.6 mm greater than the postpolypectomy measurements (p< 0.05), representing an 18% difference. Twenty-three of the 31 (74%) endoscopic estimates were larger than the postpolypectomy measurements. There was not a significant difference between the postpolypectomy and postfixation measurements.

CONCLUSIONS

The size of polyps measured endoscopically is significantly larger on average than postpolypectomy measurements. This is most likely due to factors involved in the removal of the in vivo polyp.

A double-blind, randomized, placebo-controlled, crossover trial of pentoxifylline for the prevention of chemotherapy-induced oral mucositis

Oral mucositis is a frequent side effect of cancer therapy. No effective method of prophylaxis is currently available. We conducted a randomized, double-blind, placebo-controlled, crossover trial of pentoxifylline to evaluate its potential in preventing mucositis in cancer patients receiving chemotherapy. Ten cancer patients were randomized for treatment with a 15-day course of 400 mg of pentoxifylline given orally four times daily. Concurrent chemotherapy consisted of bolus cisplatin and infusional 5-fluorouracil. Mucositis was evaluated with the use of the Oral Assessment Guide developed at the University of Nebraska. Patients completing two cycles of chemotherapy--one with pentoxifylline and one with placebo--were evaluated for prophylaxis efficacy. Comparison of the oral assessment scores of the two cycles with a two-sided Student's t test failed to demonstrate a cytoprotective effect for pentoxifylline over placebo. We conclude that pentoxifylline as given in this study is ineffective for preventing mucositis in patients receiving cisplatin and 5-FU.

How 'safe' are antioxidant vitamins?

Interest in a putative disease-preventive role for the so-called antioxidant nutrients derives from a large body of evidence suggesting that oxidative damage is a contributing cause of many life-shortening diseases. Since their use is an otherwise healthy population, it is important that such agents be virtually free of toxicity. The agents of most interest are alpha-tocopherol (vitamin E), ascorbic acid (vitamin C) and beta-carotene. When used for disease prevention, the doses given are several-fold greater the Recommended Dietary Allowance (RDA), the latter being based on amounts necessary for the prevention of classic deficiency conditions recognised decades ago. alpha-Tocopherol, ascorbic acid and beta-carotene are remarkably well tolerated and free from toxicity. Consequently, they are well suited for testing as preventive agents, since their use does not require any toxicity monitoring except in unusual circumstances. An example of the latter would be in patients who are vitamin K deficient, perhaps through anticoagulation with drugs such as warfarin, in which case use of high doses of alpha-tocopherol may increase the bleeding tendency.

Cigarette smoking and ethane exhalation in humans

The time course of exhaled ethane gas was determined in the alveolar expirate of healthy, fasting smokers and nonsmokers after smoking a cigarette. Baseline ethane was measured by gas chromatography and corrected for background ethane after a 2-min washout using purified air. Ethane was measured immediately after smoking and hourly thereafter. Ethane was highest immediately after smoking, reflecting ethane in cigarette smoke. An exponential decline of ethane in smokers returned ethane to baseline within 3 h. Ethane in nonsmokers also peaked immediately after smoking but returned to baseline by 1 h. Ethane from smokers, measured 3 h after the last cigarette, was compared with ethane from healthy ex-smokers and nonsmokers. Mean (+/- SEM) baseline ethane in smokers was 2.90 +/- 0.52 pmol/min/kg, 1.55 +/- 0.36 pmol/min/kg in ex-smokers and 1.11 +/- 0.26 pmol/min/kg in nonsmokers (p < 0.05). Ethane in two smokers measured before and after a week of oral beta carotene supplementation (60 mg/d) fell by 80 and 35%. We conclude that cigarette smokers have increased baseline ethane in exhaled breath compared with non-smokers. Trials with antioxidant agents are warranted to assess their ability to reduce expired ethane levels.

Prolactin-immunoglobulin G complexes from human serum act as costimulatory ligands causing proliferation of malignant B lymphocytes

Several lines of evidence indicate that immunoglobulin-bound prolactin found in human serum is not a conventional complex between an anti-prolactin antibody and prolactin but a different type of association of prolactin with the Fab portion of IgG heavy chains. The complex of prolactin with IgG was purified from serum by anti-human prolactin affinity chromatography and was shown to contain close to 1 mole of N epsilon-(gamma-glutamyl)lysine crosslinks per mole of complex, a characteristic feature in structures crosslinked by transglutaminase. Interestingly, the complex caused a proliferation of cells from a subset of patients with chronic lymphocytic leukemia, while it was inactive in a cell proliferation prolactin bioassay. By contrast, human prolactin stimulated the proliferation of cells in the bioassay but had no effect on the complex-responsive cells from the patients. Competition studies with prolactin and free Fc fragment of IgG demonstrated a necessity for engaging both the prolactin and the immunoglobulin receptors for proliferation. More importantly, competition for the growth response by free prolactin and IgG suggests both possible reasons for the slow growth of this neoplasm as well as avenues for control of the disease.

Antioxidants and the prevention of coronary heart disease

Oxygen-free radical reactions have been implicated in many chronic disease processes, including atherosclerotic cardiovascular disease. Recent studies of lipid metabolism have suggested that oxidative modification of low-density lipoprotein accelerates atherogenesis. Micronutrient antioxidants, including alpha-tocopherol and beta-carotene, however, can neutralize oxygen-free radicals and inhibit low-density lipoprotein oxidation. This review examines (1) the role of oxidized low-density lipoprotein in atherogenesis, (2) the association between nutritional antioxidant intake and atherosclerosis, and (3) observational and clinical trial data on the effect of antioxidants in reducing the risk of coronary heart disease. While evidence suggests that antioxidant supplements protect against coronary heart disease, definitive recommendations await results from ongoing randomized trials of primary and secondary prevention.

A low incidence of p53 mutations in pre-malignant lesions of the oral cavity from non-tobacco users

To determine the incidence of p53 mutations in pre-malignant lesions of the oral cavity from individuals without prior history of tobacco use, we have analyzed the conserved regions of the p53 gene (exons 5-9) in archival oral cavity lesion specimens obtained from patients with varied tobacco use histories, by polymerase chain reaction/single strand conformational polymorphism (PCR/SSCP) and DNA sequencing analysis. Twenty-six lesions were analyzed from 14 patients, with multiple lesions obtained from 8 patients. Six of these patients used tobacco, (3 being cigarette smokers, 1 ex-cigarette smoker, 1 moderate cigar smoker and 1 snuff chewer). The remaining 8 patients had no prior history of tobacco use. Thirteen of the pre-malignant lesions exhibited severe dysplasia, 9 exhibited moderate dysplasia and 4 exhibited mild dysplasia. Four of the 26 lesions exhibited p53 mutations, each being from a tobacco user. None of the 13 lesions from never-tobacco users exhibited p53 mutations. There was a significantly higher p53 mutation incidence in pre-malignant lesions from tobacco users (including ex-smokers) than in non-tobacco users as well as in cigarette smokers plus snuff chewers than in non-tobacco users. Two of the mutations were observed in lesions exhibiting severe dysplasia: 1 in a lesion exhibiting moderate dysplasia and 1 in a lesion exhibiting mild dysplasia. These data suggest that p53 mutation may be a very early event in oral cavity tumor progression and demonstrate that pre-malignant lesions obtained from non-tobacco users do not exhibit p53 mutations.

Emerging role of beta-carotene and antioxidant nutrients in prevention of oral cancer

beta-carotene and other antioxidant nutrients, such as vitamin E, are well suited for widespread preventive use because they are nontoxic and easily given in supplement form. Intervention trials designed to show a reduction of cancer incidence in the general population are logistically and practically impossible for most types of cancer, including cancer of the oral cavity. Thus evidence for chemoprevention must be indirect, using laboratory and animal models, epidemiologic surveys, and trials showing reversal of premalignant lesions or cancer prevention in high-risk groups. In several animal models, beta-carotene and other antioxidant nutrients inhibit oral carcinogenesis. Epidemiologic studies consistently relate low intake of these nutrients with high cancer risk. Smokers have lower beta-carotene levels in plasma and oral mucosal cells than nonsmokers. Eight clinical trials have now shown that beta-carotene and vitamin E produce regression of oral leukoplakia, but chemoprevention studies in oral leukoplakia have limitations, which we review. All available evidence supports a significant role for antioxidant nutrients in preventing oral cancer.

Demonstration of a field defect in gastric intestinal metaplasia by biological marker analysis

Gastric intestinal metaplasia (GIM) is a precursor lesion for gastric cancer. It most frequently involves the antrum and the angularis. At endoscopy, it is not possible to visually distinguish GIM from normal stomach. Furthermore, GIM frequently has a patchy distribution with areas of metaplasia coexisting with adjacent areas of other histologies, including normal stomach. In this study we sought to determine whether a "field defect" could be demonstrated in subjects with GIM, involving the entire region of the stomach. The biologic markers tested were ornithine decarboxylase (ODC) activity and bromodeoxyuridine labeling index (LI). Antral biopsies were obtained from 13 subjects with known GIM and 9 controls (no GIM based on multiple biopsies and absence of methylene blue staining). Three adjacent biopsies were obtained for ODC, LI, and histology. Group I consisted of a set of 3 biopsies from the 9 controls. In the 13 subjects with GIM, 2 sets of 3 biopsies were taken with methylene blue guidance in an attempt to obtain both GIM-free (group II) and GIM-containing (group III) tissue. ODC activities were markedly and statistically significantly (P = 0.0001) elevated in groups II and III versus group I; the mean +/- SDs were 0.075 +/- 0.117 for group I, 1.20 +/- 0.83 for group II, and 1.14 +/- 0.76 for group III. Group II versus Group III values were not different (P = 0.979). LI was less discriminatory with more overlap between the groups. The highest LI was in group II, which was significantly different from group I (P = 0.014) and group III (P = 0.006).(ABSTRACT TRUNCATED AT 250 WORDS)

Nonsteroidal antiinflammatory agents in chemoprevention of colorectal cancer. At what cost?

The objective was to provide a comparison of the known toxicities of nonsteroidal antiinflammatory drugs (NSAIDS) and the likelihood of benefit from colorectal cancer (CRC) chemoprevention attributed to them. Chemoprevention trials require large numbers of subjects followed over many years and are therefore very expensive and difficult. Hence, it is important that agents tested in these trails have a realistic expectation of actual use in the population. Data sources were published literature on the toxicity and CRC chemopreventive activity of NSAIDS. Presently available NSAIDS, used at their usual therapeutic doses, have a serious toxicity rate that quickly exceeds any benefit from CRC prevention. In contrast, low-dose aspirin is worth evaluating, especially because of the potential for simultaneous cardiovascular risk reduction. Possibly, low doses of other NSAIDS may have benefit, but this remains unproven. Synthesis of other NSAIDS, with less toxicity, is another approach towards making the toxicity-benefit ratio more favorable for the use of these agents for CRC prevention.

Gastrointestinal tissue polyamine contents of patients with Barrett's esophagus treated with alpha-difluoromethylornithine

alpha-Difluoromethylornithine (DFMO), an investigational chemopreventive agent, suppresses polyamine contents and decreases epithelial carcinogenesis in experimental models. The ability of this drug to decrease polyamine contents in human esophageal tissues has not yet been determined. Eight patients with Barrett's esophagus were treated with DFMO at a dose of 1.5 g/m2/day for 12 weeks. Four sites (Barrett's lesion, adjacent normal squamous esophagus, gastric tissue, and small bowel) were biopsied in each patient before, during, and after DFMO treatment in order to assess the effects of this drug on tissue polyamine levels. Ornithine decarboxylase activities and polyamine contents varied in each site analyzed. The rank orders were Barrett's > small bowel congruent to normal esophagus > gastric tissue for ODC activities, and small bowel > or = Barrett's congruent to normal esophagus > gastric tissue for putrescine contents. Spermidine, but not spermine, contents in the Barrett's lesions and normal squamous esophageal tissue were suppressed by systemic DFMO treatment and recovered to untreated control values when DFMO therapy was discontinued. Systemic DFMO treatment did not affect the levels of either of these two amines in gastric tissue and small bowel. Since DFMO can suppress polyamine contents in several gastrointestinal tissues, including Barrett's mucosa, we conclude that it is an effective agent with which to test the hypothesis that depletion of spermidine contents may prevent the development of adenocarcinoma of the esophagus in this specific patient group.

Influence of beta-carotene on immune functions

Recent reports have demonstrated that beta-carotene, a nontoxic carotenoid, is able to stimulate immune functions in humans. The purpose of this study is to understand the mechanisms of immunoenhancement by carotenoids in order to explain their anticancer effects. We have evaluated the clinical efficacy of beta-carotene, given 30 mg/day orally, for treatment of oral leukoplakia patients. Patients who responded to beta-carotene treatment showed increased plasma levels of TNF-alpha. Epithelial cells from these patients were characterized in vitro. These results may lead to a better understanding of the therapeutic use of beta-carotene in humans.

Review article: Barrett's oesophagus--cancer risk, biology and therapeutic management

Barrett's oesophagus is receiving increasing scrutiny as the rates of adenocarcinoma of the oesophagus rise. Because clinical features are not predictive of the presence of Barrett's oesophagus and most individuals with Barrett's oesophagus go undetected, a case can be made for surveillance endoscopy in patients with chronic reflux. Once Barrett's oesophagus is diagnosed patients should be entered into a surveillance programme despite lack of proof of efficacy. Scientific study of putative biological markers of increased risk has added dramatically to the understanding of the biology of the lesion, but currently the finding of high grade dysplasia remains the best marker predicting the presence of greatly increased risk of developing cancer. It is likely that newer molecular biology techniques will become clinically applicable biological markers in the future. Currently there is no effective medical nor surgical therapy to cause regression of the metaplastic Barrett's epithelium, however the application of novel de-differentiating agents or ablation of the metaplastic epithelium while controlling oesophageal acid exposure and other environmental abnormalities offer hope that effective treatment of Barrett's oesophagus may someday be reality.

Ornithine decarboxylase and polyamines in colorectal neoplasia and mucosa

Ornithine decarboxylase (ODC) and polyamines are intimately involved in normal cellular proliferation and are likely to play a role in carcinogenesis. ODC activity and polyamine content were measured in tissue samples obtained during colonoscopy from 48 benign neoplastic polyps (20 tubular adenomas; 28 villous adenomas), 18 cancers (including 5 malignant polyps), and adjacent mucosa. ODC activity in polyp and cancer tissue specimens was higher than in adjacent mucosa in 75 and 83% of pairs, respectively. Similarly, putrescine, spermidine, and spermine contents were higher in the majority of polyps and cancers compared to adjacent mucosa. ODC activity and polyamine content in colonic mucosa from 10 patients without a history of colorectal neoplasia were not different from adjacent mucosal values in the patients with neoplasia. In conclusion, ODC and polyamines are elevated in the majority of colorectal neoplasms, but amounts in normal mucosa do not differentiate between patients with cancer, benign neoplastic polyps, and normal subjects.

Are endoscopic measurements of colonic polyps reliable?

Many clinical studies of colorectal adenomatous polyps rely on endoscopic estimation of polyp size. To examine the reliability of such measurements, we conducted a study using artificial polyps in an endoscopy teaching model. Eight experienced endoscopists estimated the size of 13 polyps in two separate sessions 2 wk apart. Endoscopic estimates of polyp size tended to be significantly lower than the true polyp size for all polyps and all endoscopists at both sessions. We also found a statistically significant difference in the magnitude of the underestimation between the first and second session (p < 0.0001). At the first session, polyps tended to be estimated at 64% of their true size, and at the second session, the estimates tended to be at 77% of the actual polyp size. We estimate the magnitude of the variation in polyp measurements due to individual polyps, endoscopist, and examination session, and discuss the impact these sources of variation have in planning of clinical trials.

Regression of Barrett's esophagus by laser ablation in an anacid environment

Consistent regression of intestinal metaplasia in Barrett's esophagus has not been achieved with medical or surgical interventions. In this case report, a patient with Barrett's esophagus of stable length had half the circumference of the Barrett's epithelium ablated with laser therapy while on a high-dose proton-pump inhibitor. In the absence of esophageal acid exposure and after laser ablation, the intestinal metaplasia was documented to reepithelialize with normal squamous mucosa, which has persisted.

Clinical experience with the micronucleus assay

Because of the logistical and practical problems that make cancer prevention trials using cancer incidence as an endpoint virtually impossible to conduct for the majority of cancer types, there is a desperate need for valid intermediate markers of cancer risk to serve as surrogate endpoints in chemoprevention trials. A long and continually growing list of potential markers has been developed in the recent past. Unfortunately very few, if any, of them have been subjected to the usual quality control requirements for a laboratory test before being applied to clinical settings. Modulation of micronuclei frequency has been reported in a number of chemoprevention trials involving the oral cavity, esophagus, lung, and lower GI tract; however, we have focused our efforts primarily on applying the assay to exfoliated buccal mucosal cells, since much of the published data deal with this site, and oral cancer prevention is the theme of one of our chemoprevention trials. After standardizing the definition of a micronucleus by literature review and direct exchange of slides and photographs with other investigators active in the field, we obtained smears from normal subjects, smokers with or without leukoplakia, and tobacco chewers with or without leukoplakia. Our summarized findings follow: (1) Micronuclei represent only one of numerous cytological abnormalities in exfoliated buccal cells that are manifest particularly in tobacco chewers. These include a high frequency of anucleate, binucleate, and multinucleated cells, abnormal shapes and sizes of nuclei, etc.(ABSTRACT TRUNCATED AT 250 WORDS)

Beta-carotene and vitamin E in oral cancer prevention

The ultimate proof that a putative chemopreventive agent does prevent cancer is a demonstration of reduced cancer incidence in a targeted population. However, because of practical and logistical considerations, such trials are virtually impossible to conduct for the majority of cancers. Therefore, a conclusion regarding the efficacy of chemopreventive activity is based on consideration of a variety of indirect lines of evidence, including laboratory studies, animal model systems, epidemiologic surveys, intervention trials involving reversal of premalignant changes, and the prevention of malignancies in particularly high risk subjects. Furthermore, the only agents worth testing are those with limited, or preferably, no toxicity, since the final use will be prevention in a generally healthy population. Beta-carotene and vitamin E both fulfill all the criteria for suitable chemopreventive agents; several lines of evidence point toward preventive roles for them in oral cancer. In numerous epidemiologic studies, low intake of beta-carotene has been associated with higher cancer risk. Both intake and supplemental use of vitamin E have been associated with a lowered risk of cancer. Smokers, whose habit is a major risk factor, have lower beta-carotene levels in oral mucosal cells when compared with non-smokers. In several laboratory and animal model systems, including the very relevant hamster cheek pouch model, these agents strongly inhibit oral cavity carcinogenesis. Beta-carotene and vitamin E produce regression of oral leukoplakia, a premalignant lesion for oral cancer. This has now been shown in seven clinical trials: five with beta-carotene alone, one with vitamin E, and one with a combination of both.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological monitoring of cancer chemoprevention

A major limiting factor in the successful implementation of cancer chemoprevention trials has been the determination of endpoints to measure efficacy and success. The use of the ultimate goal of such trials, namely, cancer incidence, as an endpoint has serious feasibility problems, including the need for large numbers of participants, long follow-up periods, and high costs. The application of biological markers as intermediate endpoints to reveal responses to chemopreventive agents within a short time and to act as surrogates for cancer is an attractive concept worthy of intense investigation. This study reviews some potential biological markers, including genetic, cellular, biochemical, and immunological, as well as their possible application to cancer chemoprevention.

Ornithine decarboxylase assay in human colorectal mucosa. Methodologic issues of importance to quality control

Ornithine decarboxylase may be a useful biomarker for risk of neoplasia in colorectal tissues. Investigators have reported enzyme activities varying by as much as 10- to 20-fold using variations of the usual 14CO2 release assay. We have examined the effect of different methodologic factors on calculated ornithine decarboxylase activity. Major effects on the assay result (greater than 20% change) were produced by: (1) use of Tris vs. phosphate buffer, the former yielding 1.5- to 4-fold greater activity; (2) protein content of the reaction mixture with significant error if less than 50 micrograms; (3) use of alpha-difluoro-methylornithine-inhibited blank versus buffer-only blank. Other changes in assay conditions, including addition of sucrose, detergent, protease inhibitors, specific activity of 14C-ornithine, the nature of the trapping agent used, and incorporation of a sonication step, did not have a significant effect on ODC quantification (less than or equal to 20%). Thus, seemingly minor variations in assay conditions can greatly affect the results, which may provide a partial explanation for the variability of ODC activities reported in the literature. Strict quality control measures are mandatory in the interpretation of clinical observations utilizing this marker as an endpoint.