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Peter Lance

Publications and source records attributed to Peter Lance.

15 recordsLinked to original sources
PubMed2006

Cost-effectiveness analysis for health communication programs.

This article describes methods for analyzing the cost-effectiveness of health communication programs, focusing in particular on estimating program effectiveness with econometric methods that address experimental and quasi-experimental designs (and their absence), national or subnational program coverage, and endogenously targeting of programs. Experimental designs provide a gold standard for assessing effectiveness but are seldom feasible for large-scale health communication programs. Even in the absence of such designs, however, fairly simple methods can be used to examine intermediate objectives, such as program reach, which in turn can be linked to program costs to estimate cost effectiveness. When moving beyond program reach to behavioral or other outcome measures, such as contraceptive use or fertility, or when faced with full-coverage national programs, more elaborate data and methods are required. We discuss data requirements and assumptions necessary in each case, focusing on single-equation multiple regression models, structural equations models, and fixed effects estimators for use with longitudinal data, and then describing how cost information can be incorporated into econometric models so as to get measures of the cost-effectiveness of communication interventions.

Cost-Benefit Analysis↗
PubMed2006

Measuring the cost-effectiveness of a national health communication program in rural Bangladesh.

In this article we examine the cost-effectiveness of the Smiling Sun multichannel media campaign, which was undertaken in Bangladesh from 2001 to 2003 and involved a nationally broadcast television serial drama supported by radio, television, newspaper, and billboard advertisements and local promotion activities. The goal was to encourage the use of a package of family health services at NGO (nongovernmental organization) Service Delivery Program (NSDP) providers. This analysis relates the costs of the Smiling Sun campaign at the national and local level to measures of change in the use of health services, namely, antenatal care and childhood immunizations. Effectiveness is measured using data from cross-sectional surveys conducted in 2001 and 2003 in NSDP catchment areas in rural Bangladesh. The statistical approach, bivariate probit estimation, controls for nonrandom exposure to the program's media messages, advertisements, and signs. Using national-level data, we find that the Smiling Sun campaign was both effective and cost-effective, inducing higher levels of service utilization for only $0.05 per additional antenatal care (ANC) user and only $0.30 and $0.36 for each additional child vaccinated for measles and DPT3, respectively. With respect to local promotion activities, the cost per attributable behavior change was considerably higher--nearly $8 per new ANC user, $37 per new DPT3 vaccination, and $32 per new measles vaccination.

Adolescent↗
PubMed2006

High dry bean intake and reduced risk of advanced colorectal adenoma recurrence among participants in the polyp prevention trial.

Adequate fruit and vegetable intake was suggested to protect against colorectal cancer and colorectal adenomas; however, several recent prospective studies reported no association. We examined the association between fruits and vegetables and adenomatous polyp recurrence in the Polyp Prevention Trial (PPT). The PPT was a low-fat, high-fiber, high-fruit, and vegetable dietary intervention trial of adenoma recurrence, in which there were no differences in the rate of adenoma recurrence in participants in the intervention and control arms of the trial. In this analysis of the entire PPT trial-based cohort, multiple logistic regression analysis was used to estimate the odds ratio (OR) of advanced and nonadvanced adenoma recurrence within quartiles of baseline and change (baseline minus the mean over 3 y) in fruit and vegetable intake, after adjustment for age, total energyy intake, use of nonsteroidal anti-inflammatory drugs, BMI, and gender. There were no significant associations between nonadvanced adenoma recurrence and overall change in fruit and vegetable consumption; however, those in the highest quartile of change in dry bean intake (greatest increase) compared with those in the lowest had a significantly reduced OR for advanced adenoma recurrence (OR = 0.35; 95% CI, 0.18-0.69; P for trend = 0.001). The median in the highest quartile of change in dry bean intake was 370% higher than the baseline intake. The PPT trial-based cohort provides evidence that dry beans may be inversely associated with advanced adenoma recurrence.

Adenoma↗
PubMed2005

Phase III trial of ursodeoxycholic acid to prevent colorectal adenoma recurrence.

BACKGROUND: Ursodeoxycholic acid (UDCA) treatment is associated with a reduced incidence of colonic neoplasia in preclinical models and in patients with conditions associated with an increased risk for colon cancer. We conducted a phase III, double-blind placebo-controlled trial of UDCA to evaluate its ability to prevent colorectal adenoma recurrence. METHODS: We randomly assigned 1285 individuals who had undergone removal of a colorectal adenoma within the past 6 months to daily treatment with UDCA (8-10 mg/kg of body weight; 661 participants) or with placebo (624 participants) for 3 years or until follow-up colonoscopy. Recurrence rates (number of recurrent adenomas per unit time) were compared by use of a Huber-White variance estimator. Proportions of participants with one or more recurrent adenomas were compared with a Pearson chi-square statistic; adjusted odds ratios (ORs) were obtained by logistic regression. All statistical tests were two-sided. RESULTS: We observed a non-statistically significant 12% reduction in the adenoma recurrence rate associated with UDCA treatment, compared with placebo treatment. However, UDCA treatment was associated with a statistically significant reduction (P = .03) in the recurrence of adenomas with high-grade dysplasia (adjusted OR = 0.61, 95% confidence interval = 0.39 to 0.96). We observed no statistically significant differences between UDCA and placebo groups in recurrence with regard to adenoma size, villous histology, or location. CONCLUSIONS: UDCA treatment was associated with a non-statistically significant reduction in total colorectal adenoma recurrence but with a statistically significant 39% reduction in recurrence of adenomas with high-grade dysplasia. Because severely dysplastic lesions have a high risk of progression to invasive colorectal carcinoma, this finding indicates that future chemoprevention trials of UDCA in individuals with such lesions should be considered.

Adenoma↗
PubMed2005

The association between cigarette smoking and colorectal polyp recurrence (United States).

OBJECTIVE: Although evidence exists linking smoking to precancerous colorectal adenomatous polyps, few studies have examined the association between cigarette smoking and recurrence of colorectal polyps. This association was investigated prospectively with data from the Polyp Prevention Trial. METHODS: Cigarette smoking data were collected through baseline interviews. The study was completed by 1872 men and women with presence of adenomas at baseline colonoscopy. Multiple logistic regression analysis was used to examine the association between cigarette smoking and polyp recurrence (adenomatous and hyperplastic) up to four years from baseline. RESULTS: Adenoma recurrence was not related to cigarette smoking. Current smokers had increased odds of hyperplastic polyps at follow-up compared to never smokers (OR 2.88, 95% CI 2.06-4.01). Current smoking was associated with subsequent distal (OR 3.44, 95% CI 2.38-4.95) and rectal (OR 3.53, 95% CI 2.15-5.78) hyperplastic polyps, but not subsequent proximal hyperplastic polyps. Cigarette smoking was associated with subsequent multiple and small size (4 mm) hyperplastic polyps. Significant linear trends were observed between development of subsequent hyperplastic polyps and all smoking variables. CONCLUSIONS: Although no association with recurrent adenomas was observed, cigarette smoking was significantly associated with hyperplastic polyp development, except for those in the proximal colon. This prospective study confirms that cigarette smoking has a significant effect on the development of hyperplastic colorectal polyps.

Adenoma↗
PubMed2005

Analysis of colorectal cancer occurrence during surveillance colonoscopy in the dietary Polyp Prevention Trial.

BACKGROUND: Interval colorectal cancer (CRC) occasionally is detected in patients who have recently undergone colonoscopy. Systematic evaluation of CRC detected after colonoscopy could identify ways to improve the quality and the outcome of colonoscopy. METHODS: This study examined cancer diagnoses in the course of the dietary Polyp Prevention Trial, a randomized study of a dietary intervention on recurrence of adenomatous polyps. An algorithm was developed to classify each cancer into one of 4 etiologies: (1) incomplete removal (cancer at the site of previous adenoma), (2) failed biopsy detection (cancer in an area of suspected neoplasia with negative biopsy specimens), (3) missed cancer (large, advanced stage cancer found at a short interval after colonoscopy), or (4) new cancer (small, early stage cancer after a longer time interval). RESULTS: Of 2079 patients, 13 had cancer detected over 5810 person years of observation (PYO) (2.2 cases/1000 PYO); 7/13 or 53.8% of patients had either a potentially "avoidable" cancer or one detectable at an earlier time interval because of incomplete removal (4/13) or missed cancer (3/13). CONCLUSIONS: Interval cancer occurs despite colonoscopy. Improved quality of colonoscopy may have reduced cancer prevalence or resulted in earlier cancer detection in over 50% of prevalent cancers in the dietary Polyp Prevention Trial.

Aged↗
PubMed2005

Studies into the anticancer effects of selenomethionine against human colon cancer.

Colorectal cancer is the third most frequent fatal malignant neoplasm in the United States and is expected to cause significant morbidity and mortality. The recent recall of cyclooxygenase-2 inhibitors from clinical trials highlights the need to develop other agents for cancer chemoprevention trials. Intervention strategies with selenium compounds represent a viable option to reduce colon cancer. Here we discuss epidemiologic studies and ongoing clinical trials with selenium. In addition, we discuss preclinical mechanistic studies that provide insights into the biochemical and molecular bases for the anticancer effects of selenomethionine.

Animals↗
PubMed2005

A comprehensive strategy to combat colon cancer targeting the adenomatous polyposis coli tumor suppressor gene.

Somatic cells in the majority of colorectal polyps and cancers contain mutations/deletions in the adenomatous polyposis coli (APC) tumor suppressor gene. APC is involved in normal intestinal development and acts to influence a variety of cellular processes. Loss of APC function leads to intestinal neoplasia in both mice and humans. APC influences expression of specific genes, including the c-Myc oncogene, which functions as a transcriptional activator. Loss of APC function leads to alterations in c-Myc-regulated genes including ornithine decarboxylase (ODC), the first enzyme in polyamine synthesis. A single nucleotide polymorphism (SNP) in the ODC promoter affecting c-Myc-dependent expression has been associated with risk of colorectal and other cancers. Pharmaceuticals that target structural features of the c-Myc promoter, and suppress expression of c-Myc and other genes regulated by similar promoter elements, are being developed as potential colorectal cancer chemotherapies. Difluoromethylornithine (DFMO), a selective inhibitor of ODC, is under clinical evaluation as a colorectal cancer chemopreventive agent. APC and APC-dependent genes, such as c-Myc and ODC, may be useful as genetic markers of risk and as targets for chemoprevention and therapy for colorectal cancer.

Adenomatous Polyposis Coli Protein↗
PubMed2005

Karyometry in rectal mucosa of patients with previous colorectal adenomas.

OBJECTIVE: To determine whether karyometric measurements taken in biopsies from histologically normal-appearing rectal mucosa could serve as a biomarker for the risk of recurrence of polyps. MATERIALS AND METHODS: Biopsies were taken from the rectal mucosa of cases with a prior history of colonic polyps at the baseline of the study. In 57 cases recurrent polyps occurred (R cases); in 72 cases no recurrent disease was found at the end of the study (NR cases). From each biopsy 100 nuclei were recorded at high resolution. After segmentation, feature extraction and selection of a discriminating subset of features, a number of discriminant functions were derived. Also, measures of nuclear abnormality were computed. RESULTS: The differences in karyometricfeature values for nuclei from biopsies of cases with recurrent or nonrecurrent disease were very small and not notably expressed in the majority of nuclei. It was possible by focusing on nuclei showing clear deviations from normal to derive a discriminant function that exhibited a shift for the NR and R data sets. The distributions of discriminant function scores were then subjected to a second-order discriminant analysis to separate cases according to recurrence status. This function showed a statistically highly significant correlation with recurrence. At one extreme of its score distribution were 11 of 57 cases that had a recurrence, and at the other extreme were 8-10 of 72 cases that had no recurrence. The distributions of nuclear abnormality values for these subsets of cases were drastically different, with an average value of 1.72 for the group that may be at high risk for another recurrence and 1.02 for the group possibly at low risk. All cases with a prior history of colonic polyps showed a nuclear abnormality deviating from normal. CONCLUSION: Measurement of a sample of 100 nuclei from the rectal mucosa will suggest, for approximately 10% of cases, that a high risk for recurrence of adenomatous polyps exists and, for a slightly lower proportion, confirm that the nuclei deviate only slightly from those from individuals with no history of colonic polyps. For the majority of cases with a prior history of adenoma, the nuclei in the biopsy show a notable deviation from normal, but the deviation is practically the same for cases that had a recurrence and those that did not. However, a tentative discriminant function (DF I,3) derived from the characteristics of the extreme cases correctly classified approximately 64% of nonrecurrent and 83% of recurrent cases using a Bayesian decision boundary.

Adenomatous Polyposis Coli↗
PubMed2003

Cyclooxygenase-2 expression and prostanoid biogenesis reflect clinical phenotype in human colorectal fibroblast strains.

Up-regulated cyclooxygenase (COX)-2 expression and prostaglandin E2 (PGE2)synthesis contribute causally to the early stages of colorectal neoplasia and carcinogenesis, yet COX-2 expression is barely detectable in normal and premalignant colorectal epithelium. Rather, COX-2 expression in nonmalignant colonic tissue is probably confined to subepithelial cells, such as fibroblasts. We established a panel of 33 primary subepithelial fibroblast strains from human colonoscopic biopsies of normal colon (group I), normal segments of colons that harbored synchronous advanced neoplasms in remote segments (group II), advanced neoplasms (group III), and segments of active ulcerative colitis (group IV). In group I strains, mean basal and peak PGE2 levels after 24 h of interleukin (IL)-1beta stimulation were 5.4 +/- 1.1 and 32.8 +/- 4.9 ng/mg protein, respectively. Mean IL-1beta-stimulated peak levels in groups II, III, and IV strains were, respectively, 6-, 9-, and 7-fold greater than that in group I (P < 0.001 for each comparison), and inductions of COX-2 mRNA and protein were consistent with these findings. IL-1beta-mediated stimulation of PGE2 was fully blocked in the presence of a nonselective COX inhibitor (indomethacin) or a selective COX-2 inhibitor (NS-398). IL-1beta treatment elicited from group I (normal) and group III (cancer-associated) fibroblasts, respectively, approximately 2- and 3-fold inductions of COX-2 transcriptional activity and approximately 1.4- and 1.7-fold inductions of COX-2 promoter activity. This modestly greater COX-2 transcription rate could not alone account for the dramatically higher levels of COX-2 mRNA and protein and PGE2 in cancer-associated compared with normal fibroblasts. However, incubation of fibroblasts with PGE2 after IL-1beta stimulation prolonged COX-2 mRNA half-life from approximately 1 to 9 h. Our results strengthen the evidence that fibroblasts and other mesenchymal cells are the source of COX-2 expression in normal and premalignant colorectal tissue. Group II fibroblasts from normal segments of colons that harbored synchronous remote advanced neoplasms behaved like group III fibroblasts from advanced neoplasms and not group I fibroblasts from normal colons. We hypothesize that the effects of modestly greater COX-2 transcription in groups II-IV fibroblasts yield corresponding modest increases in PGE2 synthesis whose effects are progressively amplified through robust stabilization of COX-2 mRNA.

Cells, Cultured↗
PubMed2003

Non-steroidal anti-inflammatory drug use is associated with reduction in recurrence of advanced and non-advanced colorectal adenomas (United States).

OBJECTIVE: To prospectively examine the association between non-steroidal anti-inflammatory drugs (NSAIDs) use (including dose and dosage schedule) and the recurrence of colorectal adenomas among individuals who were diagnosed with an adenoma at entry into a clinical trial. METHODS: For this analysis, participants who completed the full follow-up (n = 1905) for the Polyp Prevention Trial (PPT) were evaluated. Information on current use and dose of NSAIDs and other drugs was obtained at baseline and at each subsequent study visit over the duration of the trial. The study endpoint was the recurrence of colorectal adenomas in the 3 years between the 1-year trial colonoscopy (T1) and the end of the trial colonoscopy (T4). RESULTS: There was a significant reduction in overall adenoma recurrence among NSAIDs users (odds ratio [OR] = 0.77; 95% confidence interval [CI]: 0.63-0.95), with the greatest effect seen in advanced polyps (OR = 0.51; CI: 0.33-0.79). Among aspirin users, we observed a significant dose response for overall adenoma recurrence, with a 40% reduction in the OR association (OR = 0.56; 95% CI: 0.31-0.99) among those taking more than 325 mg per day. CONCLUSION: This prospective study provides further evidence that NSAIDs may play an important role in the chemoprevention of recurrent colorectal adenomas, even those with advanced features.

Adenoma↗
PubMed2002

Adenomatous polyp recurrence and physical activity in the Polyp Prevention Trial (United States).

OBJECTIVE: To examine prospectively the association between physical activity and adenomatous polyp recurrence. METHODS: Information on past year total physical activity was collected annually through an interview-administered questionnaire from the 1905 men and women enrolled in a randomized dietary intervention study, the Polyp Prevention Trial. Multiple logistic regression analysis was used to examine the association between physical activity and polyp recurrence in up to three years of follow-up from baseline colonoscopy. RESULTS: There were no significant associations between moderate, vigorous, or total physical activity at the start of the trial and overall polyp recurrence in either men or women. Participants who reported consistent vigorous activity throughout the trial period had no significantly reduced risk of polyp recurrence compared to those who reported consistent sedentary activity (OR = 0.8, CI = 0.5-1.1). Consistent vigorous activity was also not significantly associated with either advanced or multiple polyps, nor with polyp recurrence at any specific anatomical location in the large bowel. CONCLUSIONS: These prospective data suggest that recent physical activity is not associated with polyp recurrence in a three-year period.

Adenomatous Polyps↗
PubMed2002

Ca2+- and PKC-dependent stimulation of PGE2 synthesis by deoxycholic acid in human colonic fibroblasts.

We investigated prostanoid biogenesis by human colonic fibroblasts (CCD-18Co cells and nine primary fibroblast cultures) exposed to a primary (cholic, CA) or a secondary (deoxycholic, DCA) bile acid. Basal PGE2 levels in CCD-18Co cultures and fibroblast strains initiated from normal and adenocarcinomatous colon, respectively, were 1.7 +/- 0.3, 4.0 +/- 2.0, and 15.0 +/- 4.8 ng/mg protein. Peak levels 24 h after exposure to DCA (300 microM) rose, respectively, seven-, six- and sevenfold, but CA elicited no such responses. Increases in PGE2 synthesis were preceded by sequential increases in PGH synthase-2 mRNA and protein expression and were fully prevented by a nonselective (indomethacin) or a selective (celecoxib) nonsteroidal anti-inflammatory drug. DCA, but not CA, caused abrupt, transient increases in fibroblast intracellular Ca2+ concentration ([Ca2+]i) approximately 1 min after exposure. Increased [Ca2+]i was required for DCA-mediated induction of PGE2 synthesis, and protein kinase C was a further essential component of this signaling pathway. Colonic fibroblasts may be a major target for prostanoid biogenesis induced by fecal bile acids and, potentially, other noxious actions of these agents.

Anti-Inflammatory Agents, Non-Steroidal↗