OSIRIS-REx Contamination Control Strategy and Implementation

OSIRIS-REx will return pristine samples of carbonaceous asteroid Bennu. This article describes how pristine was defined based on expectations of Bennu and on a realistic understanding of what is achievable with a constrained schedule and budget, and how that definition flowed to requirements and implementation. To return a pristine sample, the OSIRIS-REx spacecraft sampling hardware was maintained at level 100 A/2 and <180 ng/cm² of amino acids and hydrazine on the sampler head through precision cleaning, control of materials, and vigilance. Contamination is further characterized via witness material exposed to the spacecraft assembly and testing environment as well as in space. This characterization provided knowledge of the expected background and will be used in conjunction with archived spacecraft components for comparison with the samples when they are delivered to Earth for analysis. Most of all, the cleanliness of the OSIRIS-REx spacecraft was achieved through communication among scientists, engineers, managers, and technicians.

Association of fatty-acid synthase polymorphisms and expression with outcomes after radical prostatectomy

BACKGROUND

Fatty-acid synthase (FASN), selectively overexpressed in prostate cancer (PCa) cells, has been described as linked to the aggressiveness of PCa. Constitutional genetic variation of the FASN gene and the expression levels of FASN protein in cancer cells could thus be expected to predict outcome after radical prostatectomy (RP). This study evaluates the associations of malignant tissue status, neoadjuvant androgen deprivation therapy (NADT) and single-nucleotide polymorphisms (SNPs) of FASN with FASN protein expression in prostate tissue. The study then examines the associations of FASN SNPs and gene expression with three measures of post-prostatectomy outcome.

METHODS

Seven tagging FASN SNPs were genotyped in 659 European American men who underwent RP at Roswell Park Cancer Institute between 1993 and 2005. FASN protein expression was assessed using immunohistochemistry. The patients were followed for an average of 6.9 years (range: 0.1-20.6 years). Outcome was assessed using three end points: biochemical failure, treatment failure and development of distant metastatic PCa. Cox proportional hazards analyses were used to evaluate the associations of the tagging SNPs and FASN expression with these end points. Bivariate associations with outcomes were considered; the associations also were controlled for known aggressiveness indicators.

RESULTS

Overall, no SNPs were associated with any known aggressiveness indicators. FASN staining intensity was stronger in malignant than in benign tissue, and NADT was associated with decreased FASN staining in both benign and malignant tissue. The relationships of FASN SNPs and staining intensity with outcome were less clear. One SNP, rs4246444, showed a weak association with outcome. FASN staining intensity also showed a weak and seemingly contradictory relationship with outcome.

CONCLUSIONS

Additional study with longer follow-up and populations that include more metastatic patients is warranted.

Dairy products and pancreatic cancer risk: a pooled analysis of 14 cohort studies

Pancreatic cancer has few early symptoms, is usually diagnosed at late stages, and has a high case-fatality rate. Identifying modifiable risk factors is crucial to reducing pancreatic cancer morbidity and mortality. Prior studies have suggested that specific foods and nutrients, such as dairy products and constituents, may play a role in pancreatic carcinogenesis. In this pooled analysis of the primary data from 14 prospective cohort studies, 2212 incident pancreatic cancer cases were identified during follow-up among 862 680 individuals. Adjusting for smoking habits, personal history of diabetes, alcohol intake, body mass index (BMI), and energy intake, multivariable study-specific hazard ratios (MVHR) and 95% confidence intervals (CIs) were calculated using the Cox proportional hazards models and then pooled using a random effects model. There was no association between total milk intake and pancreatic cancer risk (MVHR = 0.98, 95% CI = 0.82-1.18 comparing ≥500 with 1-69.9 g/day). Similarly, intakes of low-fat milk, whole milk, cheese, cottage cheese, yogurt, and ice-cream were not associated with pancreatic cancer risk. No statistically significant association was observed between dietary (MVHR = 0.96, 95% CI = 0.77-1.19) and total calcium (MVHR = 0.89, 95% CI = 0.71-1.12) intake and pancreatic cancer risk overall when comparing intakes ≥1300 with <500 mg/day. In addition, null associations were observed for dietary and total vitamin D intake and pancreatic cancer risk. Findings were consistent within sex, smoking status, and BMI strata or when the case definition was limited to pancreatic adenocarcinoma. Overall, these findings do not support the hypothesis that consumption of dairy foods, calcium, or vitamin D during adulthood is associated with pancreatic cancer risk.

Addressing tobacco use and cessation in cancer patients: Practices, perceptions, and barriers reported by oncology providers

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Background: Tobacco use is associated with adverse outcomes in cancer patients, but there are limited data on tobacco cessation support by oncology providers. Methods: Duplicate surveys were sent to the membership of the International Association for the Study of Lung Cancer (IASLC) and the American Society of Clinical Oncology (ASCO) asking about tobacco assessment and cessation practices, perceptions of tobacco use by cancer patients, and barriers to implementing tobacco cessation. The results of 1,507 responses from IASLC and 1,197 responses from ASCO are reported. Results: At initial consult, most respondents asked about tobacco use (90% in both surveys), asked if smokers would quit tobacco use (79-80%), advised patients to stop smoking (81-82%). Most respondents felt that tobacco affects cancer outcomes (87-92%) and that tobacco cessation should be a standard part of clinical care (86-90%). However, few discussed medication options (40-44%) or actively provided smoking cessation assistance (39% in both surveys). Fewer respondents asked about tobacco use at follow-up and few reported adequate tobacco cessation training (29-33%). Dominant barriers to providing cessation interventions included patient resistance to cessation treatment (67-74%) and inability to get patients to quit tobacco use (58-72%), but very few believed tobacco cessation was a waste of time (8-12%). Lack of time, reimbursement, lack of training, and lack of resources were reported as barriers in less than 50% of respondents. Conclusions: Oncology providers feel tobacco affects cancer outcomes and cessation should be a standard part of clinical care. Most assess tobacco use, but few discuss medication options or provide active cessation support. Efforts are needed to improve cessation methods in cancer patients and to improve access to tobacco cessation support for cancer patients.

Increasing access to tobacco cessation support for cancer patients: Results of an institution-wide screening and referral program in an NCI-designated comprehensive cancer center

1566

Background: Guidelines from ASCO and other national organizations recommend assessment of tobacco use and structured tobacco cessation support for cancer patients. However, most oncology providers fail to provide cessation assistance to cancer patients who use tobacco. Reported are results of a systematic approach to assessing tobacco use and delivering cessation support for cancer patients in a comprehensive cancer center. Methods: A standard set of evidence based tobacco assessment questions were incorporated into an automated electronic medical record based system delivered by nursing at initial consult and follow-up. Patients eligible for tobacco cessation support (i.e. patients self-reporting tobacco use within 30 days) were automatically referred to a dedicated tobacco cessation service providing primarily phone based cessation support. Results: Of approximately 11,900 patients screened over 26 months, 2,978 patients were automatically triaged for cessation support. Contact priority was given to newly diagnosed patients in tobacco related disease sites. Using 1.25 full time cessation specialists, 1,531 received only a standard tobacco cessation mailing and no further contacts were attempted by the cessation service. In 1447 patients with attempted phone contact by the cessation service, 1189 (82.2%) were reached within 5 contact attempts. In 1,189 patients contacted, 52 (4.4%) were inappropriate referrals, 245 (20.6%) were in an active quitting phase, 465 (39.1%) were willing to prepare, and only 24 (2.0%) refused any intervention at initial contact. At the most recent follow-up, 44 patients (3.7%) requested no further contact and 90 additional patients (7.6%) were lost to follow-up. In the 1,045 remaining patients, 338 (32.3%) reported quitting tobacco use. Notably, in the 1,531 patients with no phone contact by the cessation service, only 14 proactively contacted the cessation service for assistance. Conclusions: An institution wide program to automate the delivery of tobacco cessation services was feasible with high patient contact rates, low patient refusal, and moderately high tobacco cessation rates.

Change in mammographic density with metformin use: A companion study to NCIC study MA.32

TPS1608

Background: Metformin may have growth inhibitory effects on many cancer types including breast cancer. NCIC MA.32 is a randomized placebo-controlled trial examining the effects of 5 years of metformin in women with breast cancer ( http://clinicaltrials.gov/show/NCT01101438 ). This trial offers us the opportunity to explore the effects of metformin on breast cancer biomarkers to gain an understanding of the potential chemo preventive effects of this drug. The primary aim of this companion to MA.32 (Alliance trial # A211201) is to examine the effects of 1 year of metformin vs placebo on breast density for women with Estrogen Receptor negative (ER-) breast cancer. Secondary aims of this study include: evaluation of breast density following 2 years of metformin use, and correlation of density with fasting insulin, glucose and Homeostasis Model Assessment (HOMA). Exploratory aims include examination of the effects of metformin on second cancer rates. Methods: Eligible women must have been enrolled on MA.32 (North America accrual completed January 23, 2013), have hormone receptor-negative breast cancer, and breast composition on mammography >25% glandular density, have a digital mammogram within 12 months of registration on MA.32 and have an intact, unaffected contralateral breast. Women enrolled on this study must provide menstrual cycle data (if premenopausal) and digital mammograms. All other study related information is gathered through participation in MA.32. Mammographic density will be calculated using Cumulus software (the Boyd method). Our accrual goal is 458 patients (229 per arm) and with an assumption of 20% drop out due to drug intolerance and another 20% due to ineligibility. Therefore, with a sample size of 274 (137 per arm) we will have at least 85% power to detect a 4% difference between study arms, i.e., 5% change from baseline to one year of treatment for metformin vs. 1% for placebo, using the two-sided two-sample t-test at a significance level of 5%. This study was activated in the United States on 8/22/2012 and 15 patients have been accrued to date. This study is sponsored by the NCI and the Alliance for clinical trials. Clinical trial information: NCT01666171.

The effect of BMI at time of surgery on long-term outcome after radical prostatectomy

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Background: Body mass index (BMI) at time of surgery was determined among 715 radical prostatectomy patients. The association of BMI with a range of treatment outcomes was considered. Methods: The associations of BMI at time of radical prostatectomy (RP) with disease stage and aggressiveness and long-term outcome were evaluated among 715 patients treated with RP at Roswell Park Cancer Institute between 1993 and 2005. Clinical and pathological aggressiveness indicators included clinical Gleason sum and tumor stage (2002 TNM), highest preoperative PSA, pathological Gleason sum and tumor stage (2002 TNM) and surgical margin status. Ten post-RP recurrence definitions were considered: 1) PSA ≥ 0.2 ng/ml; 2) PSA ≥ 0.4 ng/ml (with 1 confirming value); 3) 1 or more post RP treatments (ADT, radiation, chemotherapy); 4) PSA doubling time < 12 months; 5) PSA doubling time < 9 months; 6) PSA doubling time < 6 months; 7) NCCN definition of PSA failure; 8) AUA definition of PSA failure; 9) diagnosis of metastatic CaP; and 10) death from CaP. Results: Of the 715 men, 33 developed metastatic prostate cancer, and 17 died of prostate cancer. 246 men had BMI ≥ 30. BMI was not significantly associated with clinical or pathological aggressiveness criteria. These analyses showed that there is a trend towards higher risk of the development of metastasis or death for men with BMI ≥ 30, although the association with high BMI and these failure types is not significant. With adjustment for the most significant tumor aggressiveness features (clinical Gleason sum, pathological tumor stage, pathological Gleason sum, and surgical margin status) in proportional hazards regression, men with BMI ≥ 30 had consistently lower risk for all definitions of recurrence except metastasis and death, although no hazard ratios were significant. In contrast, men with higher BMIs had higher risk for metastasis and death from prostate cancer, although neither association is statistically significant. Conclusions: Men with higher BMIs show similar to slightly reduced risk for PSA-based recurrence definitions. Men with higher BMIs had slightly higher risk, though not significant, for metastasis and death. These results seem to support theories that PSA is diluted in men with higher BMIs.

Selenium and prevention of prostate cancer in high-risk men: the Negative Biopsy Study

Epidemiological and clinical studies suggesting a significant inverse relationship between intake of dietary selenium and overall cancer risk have led to initiation of a randomized, placebo-controlled, phase III clinical trial testing the safety and efficacy of selenized yeast as a chemopreventive agent for prostate cancer. Participants eligible for the 'Negative Biopsy Study', which was initiated in August 1999, are men considered to be at high risk for prostate cancer because of at least one negative sextant prostate biopsy, which was clinically indicated within 1 year of enrollment to the study. After a 30-day run-in period to ensure protocol compliance, participants are randomized to receive either 200 or 400 microg selenized yeast or matched placebo once daily. Primary study endpoints include development of prostate cancer and prostate-specific antigen (PSA) velocity. Secondary biochemical endpoints include change in chromagranin A and alkaline phosphatase. As of 1 June 2003, 514 eligible participants had been enrolled. Randomization schema was effective for selected parameters including age, body mass index, smoking status, baseline PSA and baseline plasma selenium level. Various data, including medical history, family history, and urological symptoms and specimens (including blood and subsequent prostate biopsy samples) had been collected at baseline, and throughout both the intervention and follow-up stages of the protocol. The goal for accrual is 700 evaluable participants.

Selenium and inhibition of disease progression in men diagnosed with prostate carcinoma: study design and baseline characteristics of the ‘Watchful Waiting’ Study

Impediment of the promotion and progression stages of carcinogenesis of the prostate could have a profound impact on treatment choice and prognosis for prostate cancer. Efficacious chemopreventive agents that elicit their activity by slowing the processes of progression could make watchful waiting a viable alternative for a large population of men or could delay the necessity for surgery, radiation or other more invasive treatment modalities associated with frequent side effects. Reports from the Nutritional Prevention of Cancer (NPC) study reported that dietary supplementation with selenium significantly reduced the risk of developing prostate cancer. These data led to initiation of the Watchful Waiting Study, a phase II, multi-center, randomized, double-blind, placebo-controlled clinical intervention study testing the effects of two doses of selenized yeast on progression of prostate cancer. Participants are men with biopsy-proven prostate cancer who have elected to forgo therapy and be closely followed by 'watchful waiting' that includes quarterly prostate-specific antigen (PSA) screening. Subjects are randomized to receive 200 or 800 microg of selenized yeast or matched placebo daily. Endpoints include time to disease progression and PSA velocity. Secondary endpoints include time to initiation of therapy as well as biochemical markers of disease progression including chromagranin A and alkaline phosphatase. Immunohistochemical analyses for indicators of apoptosis, proliferation and differentiation will be performed on baseline and subsequent prostate biopsy specimens. This report summarizes the primary objectives, research methods and the randomized subjects in this important clinical trial.

Selenium supplementation, baseline plasma selenium status and incidence of prostate cancer: an analysis of the complete treatment period of the Nutritional Prevention of Cancer Trial

OBJECTIVE

To present the results (to January 1996, the end of blinded treatment) of the Nutritional Prevention of Cancer (NPC) Trial, a randomized trial of selenium (200 micro g daily) designed to test the hypothesis that selenium supplementation (SS) could reduce the risk of recurrent nonmelanoma skin cancer among 1312 residents of the Eastern USA.

MATERIALS AND METHODS

Original secondary analyses of the NPC to 1993 showed striking inverse associations between SS and prostate cancer incidence. A subsequent report revealed that this effect was accentuated among men with the lowest baseline plasma selenium concentrations. The effects of treatment overall and within subgroups of baseline prostate-specific antigen (PSA) and plasma selenium concentrations were examined using incidence rate ratios and Cox proportional hazards models.

RESULTS

SS continued to significantly reduce the overall incidence (relative risk and 95% confidence interval) of prostate cancer (0.51, 0.29-0.87). The protective effect of SS appeared to be confined to those with a baseline PSA level of <or= 4 ng/mL (0.35, 0.13-0.87), although the interaction of baseline PSA and treatment was not statistically significant. Participants with baseline plasma selenium concentrations only in the lowest two tertiles (< 123.2 ng/mL) had significant reductions in prostate cancer incidence. A significant interaction between baseline plasma selenium and treatment was detected.

CONCLUSION

To the end of the blinded treatment the NPC trial continued to show a significant protective effect of SS on the overall incidence of prostate cancer, although the effect was restricted to those with lower baseline PSA and plasma selenium concentrations.

Larry Clark's legacy: randomized controlled, selenium-based prostate cancer chemoprevention trials

Several important clinical trials under way at the Arizona Cancer Center seek to build on the results of Clark's 1996 study of selenium and decreased risk of prostate cancer. Those results, an unanticipated end point of a clinical trial, suggest that selenium has significant preventive power. The studies under way involve continued follow-up of the study cohort that generated the 1996 results and trials of selenium among men with negative biopsies, men with high-grade prostatic intraepithelial neoplasia, men with prostate cancer treated with selenium before prostatectomy, and men with prostate cancer who have chosen watchful waiting rather than active intervention. These studies promise important opportunities to validate Clark's original results.

Stress and suicide in the Nurses' Health Study

STUDY OBJECTIVES

Although stress is thought to be a risk factor for suicide, most research has been retrospective or has focused on attempted suicides or suicide ideation. This study examined prospectively the associations between self perceived stress, diazepam use, and death from suicide among adult women.

DESIGN

A cohort study was conducted with 14 years of follow up. Stress at home and at work were assessed by questionnaire and scored on a four point scale: minimal, light, moderate, or severe.

SETTING

Eleven states within the United States.

PARTICIPANTS

Female nurses (n=94 110) who were 36 to 61 years of age when they answered questions on stress and diazepam use in 1982.

RESULTS

During 1 272 000 person years of observation 73 suicides were identified. After adjustment for age, smoking, coffee consumption, alcohol intake, and marital status, the relation between self reported stress and suicide remained U shaped. Compared with the light home and work stress categories, which had the lowest incidences of suicide, risks were increased among women reporting either severe (relative risk (RR) = 3.7, 95% confidence intervals (CI) 1.7 to 8.3) or minimal (RR=2.1, 95% CI 1.0 to 4.5) home stress and either severe (RR=1.9, 95% CI 0.8 to 4.7) or minimal (RR=2.4, 95% CI 0.9 to 6.1) work stress. When responses to home and work stress were combined, there was an almost fivefold increase in risk of suicide among women in the high stress category. Risk of suicide was over eightfold among women reporting high stress or diazepam use compared with those reporting low stress and no diazepam use.

CONCLUSIONS

The relation between self reported stress and suicide seems to be U shaped among adult women. The excess risk for those reporting minimal stress may reflect denial or undiagnosed depression or an association with some other unmeasured risk factor for suicide.

Sn-Mesoporphyrin interdiction of severe hyperbilirubinemia in Jehovah's Witness newborns as an alternative to exchange transfusion

OBJECTIVE

The religious convictions of parents who are Jehovah's Witness adherents lead them to reject the use of exchange transfusions as therapy for severe hyperbilirubinemia in newborns in whom intensive phototherapy has failed to control this problem. Consequently, physicians caring for such infants may be obliged to initiate legal action to compel use of the procedure when severe hyperbilirubinemia not sufficiently responsive to phototherapy warrants an exchange transfusion. Our goal was to determine if we could use the potent inhibitor of bilirubin production, Sn-Mesoporphyrin (SnMP), to resolve the troubling medical-legal issues in such situations in 2 infants with hemolytic disease of the newborn who required exchange transfusions for severe hyperbilirubinemia but whose Jehovah's Witness parents rejected the procedure. SnMP was administered in a single dose, as in previous studies, at the time when exchange transfusion would have been initiated and plasma bilirubin levels were monitored at close intervals thereafter.

METHODS

SnMP is a potent inhibitor of heme oxygenase, the rate-limiting enzyme in catabolism of heme to bilirubin. We found in earlier studies that in single doses of 6 micromol/kg birth weight, SnMP is extremely effective in moderating the course of hyperbilirubinemia and in eliminating the need for supplemental phototherapy in jaundiced newborns. In the 2 cases described, a single dose of SnMP (6 micromol/kg birth weight) was administered intramuscularly to severely jaundiced infants with immune hemolysis at a time when clinical circumstances dictated the need for exchange transfusion. CASE 1: This patient was a preterm male infant (gestational age: 35 5/7 weeks; birth weight: 2790 g) whose plasma bilirubin concentration (PBC) at 1 hour after birth was 5.0 mg/dL. Despite intensive phototherapy with 3 banks of lights and 1 biliblanket, the PBC increased steadily with no diminution in the rate of increase for 75 hours. In view of the problems of immune hemolysis, and prematurity, and the inability of phototherapy to stop progression of hyperbilirubinemia, a decision to carry out an exchange transfusion was made; the decision was, however, rejected by the Jehovah's Witness parents. Pending legal action to compel use of the procedure, a request to this (Rockefeller) laboratory for SnMP was made; its use was approved by the Food and Drug Administration; and the inhibitor was delivered to the physician-in-charge (D.P.M.) in Sioux Falls, South Dakota. The single dose of SnMP was administered to the infant at 75 hours after birth; the course of hyperbilirubinemia before and after the use of the inhibitor is shown in Fig 1. [figure: see text]. CASE 2: This female term infant (gestational age: 38-39 weeks; birth weight: 4140 g) with immune hemolysis was delivered by cesarean section and because of problems related to meconium aspiration required helicopter transfer to the Special Care Nursery in Abilene, Texas, where 10 hours after birth the first PBC was determined to be 18.0 mg/dL. Double-bank phototherapy plus a biliblanket was initiated; a third bank of lights was later ordered. The PBC fluctuated in the ensuing 2 days between 13.8 to 25.8 mg/dL during which suggestive clinical signs of possible bilirubin encephalopathy became manifest. In view of the clinical circumstances and the continued severe hyperbilirubinemia, permission for a double-exchange transfusion was requested. The parents, who were Jehovah's Witness adherents, refused the procedure. While preparing legal action to compel use of the exchange, a request was made to this (Rockefeller) laboratory for use of SnMP to attempt control of hyperbilirubinemia. With FDA approval, the SnMP was delivered to the attending neonatologist (J. R. M.) in Abilene and administered in a single dose (6 micromol/kg birth weight) at 56 hours after birth when the PBC was 19.5 mg/dL. The course of bilirubinemia before and after SnMP use is shown in Fig 2. [figure: see text].

RESULTS AND CONCLUSIONS

The use of SnMP to moderate or prevent the development of severe hyperbilirubinemia in newborns (preterm, near-term, term with high PBCs [15-18 mg/dL], ABO-incompatibility; glucose-6-phosphate dehydrogenase deficiency) has been extensively studied in carefully conducted clinical trials the results of which have been reported earlier. This inhibitor of bilirubin production has demonstrated marked efficacy in moderating the course of hyperbilirubinemia in all diagnostic groups of unconjugated neonatal jaundice. The 2 cases described in this report confirmed the efficacy of SnMP in terminating progression of hyperbilirubinemia in infants in whom phototherapy had failed to sufficiently control the problem and whose parents, for religious reasons, would not permit exchange transfusions. Interdiction of severe hyperbilirubinemia by inhibiting the production of bilirubin with SnMP can be an effective alternative to the use of exchange transfusion in the management of severe newborn jaundice that has not responded sufficiently to light treatment to ease concern about the development of bilirubin encephalopathy.

Analysis of patterns of food intake in nutritional epidemiology: food classification in principal components analysis and the subsequent impact on estimates for endometrial cancer

OBJECTIVE

To assess the effect of different methods of classifying food use on principal components analysis (PCA)-derived dietary patterns, and the subsequent impact on estimation of cancer risk associated with the different patterns.

METHODS

Dietary data were obtained from 232 endometrial cancer cases and 639 controls (Western New York Diet Study) using a 190-item semi-quantitative food-frequency questionnaire. Dietary patterns were generated using PCA and three methods of classifying food use: 168 single foods and beverages; 56 detailed food groups, foods and beverages; and 36 less-detailed groups and single food items.

RESULTS

Classification method affected neither the number nor character of the patterns identified. However, total variance explained in food use increased as the detail included in the PCA decreased (approximately 8%, 168 items to approximately 17%, 36 items). Conversely, reduced detail in PCA tended to attenuate the odds ratio (OR) associated with the healthy patterns (OR 0.55, 95% confidence interval (CI) 0.35-0.84 and OR 0.77, 95% CI 0.49-1.20, 168 and 36 items, respectively) but not the high-fat patterns (OR 0.95, 95% CI 0.57-1.58 and OR 0.85, 0.51-1.40, 168 and 36 items, respectively).

CONCLUSIONS

Greater detail in food-use information may be desirable in determination of dietary patterns for more precise estimates of disease risk.

Ki-ras proto-oncogene mutations in sporadic colorectal adenomas: relationship to histologic and clinical characteristics

BACKGROUND & AIMS

[corrected] The goal of this study was to examine the relationship between Ki-ras mutations in colorectal adenomas and characteristics of both the subject (age, gender, and family/personal history of colonic neoplasia) and the adenoma (multiplicity, size, location, and histologic features).

METHODS

Ki-ras mutations were detected by direct sequencing in 738 adenomatous polyps removed at baseline from 639 participants in a nutritional trial of adenoma recurrence.

RESULTS

Ki-ras mutations were detected in 17.2% of the adenomas. Ki-ras mutations were unrelated to gender, family, or personal history of colonic neoplasia, location within the colorectum, or adenoma multiplicity, but were more common in older subjects (P = 0.01 for trend), in larger adenomas (P < 0.0001 for trend), in adenomas with villous histology (odds ratio [OR], 3.2; 95% confidence interval [CI], 2.1-4.9 vs. tubular), and in adenomas with high-grade dysplasia (32.0% vs. 13.6%; OR, 3.0; 95% CI, 1.9-4.6 vs. low-grade dysplasia). Multivariate analysis showed Ki-ras mutations to be independently associated with subject age (P = 0.01 for trend), tubulovillous/villous histology (OR, 2.3; 95% CI, 1.5-3.7), and high-grade dysplasia (OR, 1.9; 95% CI, 1.2-3.1). Adenoma size was not independently related to Ki-ras mutation.

CONCLUSIONS

Ki-ras mutations are associated with the histologic features of adenoma progression (villous histology and high-grade dysplasia) rather than with adenoma growth.

Inverse associations between plasma lycopene and other carotenoids and prostate cancer

Although dietary intake of tomatoes and tomato products containing lycopene has been reported to reduce the risk of prostate cancer, few studies have been done on the relationship between plasma lycopene and other carotenoids and prostate cancer. This case-control study was conducted to investigate the effects of plasma lycopene, other carotenoids, and retinol, as well as alpha- and gamma-tocopherols on the risk of prostate cancer. The study included 65 patients with prostate cancer and 132 cancer-free controls; all of them were interviewed using a standard epidemiological questionnaire at the Memorial Sloan-Kettering Cancer Center from 1993 to 1997. Plasma levels of carotenoids, retinol, and tocopherols were measured by high performance liquid chromatography. An unconditional logistic regression model was used in bivariate and multivariate analyses using Statistical Analysis System (SAS). After adjusting for age, race, years of education, daily caloric intake, pack-years of smoking, alcohol consumption, and family history of prostate cancer, significantly inverse associations with prostate cancer were observed with plasma concentrations of the following carotenoids: lycopene [odds ratio (OR), 0.17; 95% confidence interval (CI), 0.04-0.78; P for trend, 0.0052] and zeaxanthin (OR, 0.22; 95% CI, 0.06-0.83; P for trend, 0.0028) when comparing highest with lowest quartiles. Borderline associations were found for lutein (OR, 0.30; 95% CI, 0.09-1.03; P for trend, 0.0064) and beta-cryptoxanthin (OR, 0.31; 95% CI, 0.08-1.24; P for trend, 0.0666). No obvious associations were found for alpha- and beta-carotenes, retinol, and alpha- and gamma-tocopherols. Our study confirmed the inverse associations between lycopene, other carotenoids such as zeaxanthin, lutein, and beta-cryptoxanthin, and prostate cancer. This study provides justification for further research on the associations between lycopene and other antioxidants and the risk of prostate cancer.

High-grade prostatic intraepithelial neoplasia as an exposure biomarker for prostate cancer chemoprevention research

There is a tremendous need for exposure biomarkers, which need to function as intermediate end-points in cancer chemoprevention studies. Likely candidates include process biomarkers, atypical adenomatous hyperplasia, and a newly identified atrophic state. High-grade prostatic intraepithelial neoplasia (HGPIN) has the potential to be a useful exposure biomarker, having substantial predictive value for prostate cancer in chemoprevention trials. A limitation of the use of HGPIN as a biomarker is accessibility, since it requires the use of a highly invasive procedure that would not normally be applied unless malignancy is suspected to be present. However, most other biomarkers of prostatic tissue are similarly invasive. The HGPIN lesion appears to be highly measurable; however, problems of sampling coupled with the heterogeneity of the prostate raise questions about the degree to which the presence of HGPIN can be seen to characterize a given person's prostate gland. HGPIN has the advantage that it appears to be quite highly proximal to the development of cancer and to be modifiable. It remains less clear to what degree it reflects the exposures that are believed to alter prostate cancer risk. HGPIN has been identified as a clinical entity only recently and much additional research on the utility of this marker is needed.

Adenoma characteristics as risk factors for recurrence of advanced adenomas

BACKGROUND AND AIMS

The link between adenoma characteristics at baseline colonoscopy and adenoma recurrence is poorly understood. We assessed whether the number, size, location, or histology of resected adenomas was related to the probability of recurrence of advanced lesions.

METHODS

Analyses were based on 1287 men and women in the wheat bran fiber (WBF) study, a randomized, double-blind trial of WBF as a means of decreasing the probability of adenoma recurrence over a period of 3 years. Multiple logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Recurrence of advanced adenomas (>1 cm or tubulovillous/villous histology) was higher among individuals with adenomas >1 cm compared with those with adenomas <0.5 cm (OR, 2.69; 95% CI, 1.34-5.42) and among those with proximal than those with distal adenomas (OR, 1.65; 95% CI, 1.02-2.67). No association was observed for adenoma number or histology. A shift in location from the distal colon and rectum at baseline (54.6%) to more proximal recurrent adenomas (45.2%), including advanced lesions (42.8%), was observed.

CONCLUSIONS

Large or proximally located adenomas are important indicators of recurrence of advanced lesions. Because most recurrences were detected in the proximal colon, careful surveillance of this area is warranted.

Randomized, controlled chemoprevention trials in populations at very high risk for prostate cancer: Elevated prostate-specific antigen and high-grade prostatic intraepithelial neoplasia

This is a report of research efforts underway at the Arizona Cancer Center. These efforts build upon Larry Clark's unanticipated clinical prevention trial results: those results indicated that 200 microg/day of selenium in selenized yeast decreased prostate cancer risk by almost 60%. The trials underway address various phases of the possible preventive activity of selenium. The first of these, for men who are suspected to have prostate cancer but who have had a biopsy revealing no evidence of cancer, will test the ability of selenium to prevent the development of clinical prostate cancer. The second is for men with high-grade prostatic intraepithelial neoplasia; the trial will test whether selenium will prevent the development of prostatic cancer in this high-risk group. The third trial is for men who have been diagnosed with prostate cancer and are scheduled for prostatectomy: the trial is designed to test whether evidence of selenium-linked changes can be identified in the tissue removed at prostatectomy. The fourth trial is for men who have been diagnosed with prostate cancer but who have chosen neither surgery nor irradiation; this trial will evaluate whether treatment with selenium will inhibit the progress of prostate cancer. Together, these trials will provide important information as to the prostate cancer chemopreventive potential of selenium.

Diet in the epidemiology of endometrial cancer in western New York (United States)

OBJECTIVES

We examined diet and risk of endometrial cancer among women in the Western New York Diet Study (1986-1991).

METHODS

Self-reported frequency of use of 172 foods and beverages during the 2 years before the interview and other relevant data were collected by detailed interviews from 232 endometrial cancer cases and 639 controls, frequency-matched for age and county of residence. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by unconditional logistic regression, adjusting for age, education, body mass index (BMI), smoking history, hypertension, diabetes, age at menarche, parity, oral contraceptive use, menopausal status, menopausal estrogen use, and energy.

RESULTS

Risks were reduced for women in the highest quartiles of intake of protein (OR 0.4, 95% CI: 0.2-0.9), dietary fiber (OR 0.5, 95% CI: 0.3-1.0), phytosterols (OR 0.6, 95% CI: 0.3-1.0), vitamin C (OR 0.5, 95% CI: 0.3-0.8) folate (OR 0.4, 95% CI: 0.2-0.7), alpha-carotene (OR 0.6, 95% CI: 0.4-1.0), beta-carotene (OR 0.4, 95% CI: 0.2-0.6), lycopene (OR 0.6, 95% CI: 0.4-1.0), lutein + zeaxanthin (OR 0.3, 95% CI: 0.2-0.5) and vegetables (OR 0.5, 95% CI: 0.3-0.9), but unrelated to energy (OR 0.9, 95% CI: 0.6-1.5) or fat (OR 1.6, 95% CI: 0.7-3.4).

CONCLUSIONS

Our results support previous findings of reduced endometrial cancer risks associated with a diet high in plant foods.

Reduction in fat intake is not associated with weight loss in most women after breast cancer diagnosis: evidence from a randomized controlled trial

BACKGROUND

A reduction in dietary fat intake has been suggested as a method to promote weight loss in women at risk for breast cancer recurrence.

METHODS

Weight change in response to diet intervention was examined in 1010 women who had completed treatment for Stage I, Stage II, or Stage IIIA (American Joint Committee on Cancer staging system) primary operable breast cancer during their first year of participation in a randomized, controlled, diet intervention trial to reduce risk of recurrence. Diet intervention was performed by telephone counseling and promoted a low fat diet that also was high in fiber, vegetables, and fruit. The comparison group was provided with general dietary guidelines to reduce disease risk. Multiple linear regression models were used to examine the relations among demographic and personal characteristics, changes in diet composition and exercise level, and change in body weight or body mass index.

RESULTS

The average weight change in the 1-year period was 0.04 kg for the intervention group and 0.46 kg for the comparison group. For the total group, body weight was stable (+/- 5% baseline weight) for 743 women (74%), whereas 114 (11%) lost weight, and 153 (15%) gained weight. These distributions were similar in the two study groups inclusive of all study participants and for only those women with a baseline body mass index of > or = 25 kg/m2. Initial body mass index and changes in fiber and vegetable intakes, but not change in percent of energy obtained from fat, were associated independently with change in weight or body mass index.

CONCLUSIONS

For most women at risk for breast cancer recurrence, diet intervention to promote a reduction in fat intake was not associated with significant weight loss. Testing the effect of a substantial change in diet composition on risk for breast cancer recurrence is unlikely to be confounded by weight loss in subjects who were the recipients of intensive intervention efforts.

Effects of piroxicam on prostaglandin E2 levels in rectal mucosa of adenomatous polyp patients: a randomized phase IIb trial

Prostaglandin E2 (PGE2) has served as a surrogate end point biomarker in colorectal tumor progression. Colonic mucosa PGE2 levels of patients with colorectal adenomas or carcinomas have been shown to be higher than in control subjects. Our dose-finding study on piroxicam, a nonsteroidal anti-inflammatory drug with chemopreventive effects in preclinical colon carcinoma models, suggested that 7.5 mg/day was well tolerated and associated with significant depression of rectal mucosa PGE2 concentrations in comparison with baseline values. We therefore conducted a randomized Phase IIb cancer prevention clinical trial to investigate the chemopreventive properties of piroxicam in patients with a history of resected colorectal adenomatous polyps. After a 2-month run-in period, 47 participants were randomized to piroxicam at a dose of 7.5 mg/day, and 49 were randomized to a placebo. Rectal biopsy specimens were taken at the initial visit, at 2 months later during the run-in period, and at 6, 12, and 24 months after the start of the interventions. Mean PGE2 concentrations in the rectal mucosa of the piroxicam-treated patients differed significantly between visits (P < 0.001), and the values at the 6-month visit (P < 0.001) and 12-month visit (P = 0.005) differed significantly from the average baseline value. Unfortunately, we observed an incidence of adverse gastrointestinal side effects in patients treated with 7.5 mg/day of piroxicam similar to that seen for arthritis patients treated with 20 mg/day. Consequently, the gastrointestinal toxicities appear to override the potential benefit that piroxicam may offer as a long-term colon cancer chemopreventive agent.

Diet in the epidemiology of endometrial cancer in western New York (United States)

OBJECTIVES

We examined diet and risk of endometrial cancer among women in the Western New York Diet Study (1986-1991).

METHODS

Self-reported frequency of use of 172 foods and beverages during the 2 years before the interview and other relevant data were collected by detailed interviews from 232 endometrial cancer cases and 639 controls, frequency-matched for age and county of residence. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by unconditional logistic regression, adjusting for age, education, body mass index (BMI), smoking history, hypertension, diabetes, age at menarche, parity, oral contraceptive use, menopausal status, menopausal estrogen use, and energy.

RESULTS

Risks were reduced for women in the highest quartiles of intake of protein (OR 0.4, 95% CI: 0.2-0.9), dietary fiber (OR 0.5, 95% CI: 0.3-1.0), phytosterols (OR 0.6, 95% CI: 0.3-1.0), vitamin C (OR 0.5, 95% CI: 0.3-0.8) folate (OR 0.4, 95% CI: 0.2-0.7), alpha-carotene (OR 0.6, 95% CI: 0.4-1.0), beta-carotene (OR 0.4, 95% CI: 0.2-0.6), lycopene (OR 0.6, 95% CI: 0.4-1.0), lutein + zeaxanthin (OR 0.3, 95% CI: 0.2-0.5) and vegetables (OR 0.5, 95% CI: 0.3-0.9), but unrelated to energy (OR 0.9, 95% CI: 0.6-1.5) or fat (OR 1.6, 95% CI: 0.7-3.4).

CONCLUSIONS

Our results support previous findings of reduced endometrial cancer risks associated with a diet high in plant foods.

Pooled analysis of prospective cohort studies on height, weight, and breast cancer risk

The association between anthropometric indices and the risk of breast cancer was analyzed using pooled data from seven prospective cohort studies. Together, these cohorts comprise 337,819 women and 4,385 incident invasive breast cancer cases. In multivariate analyses controlling for reproductive, dietary, and other risk factors, the pooled relative risk (RR) of breast cancer per height increment of 5 cm was 1.02 (95% confidence interval (CI): 0.96, 1.10) in premenopausal women and 1.07 (95% CI: 1.03, 1.12) in postmenopausal women. Body mass index (BMI) showed significant inverse and positive associations with breast cancer among pre- and postmenopausal women, respectively; these associations were nonlinear. Compared with premenopausal women with a BMI of less than 21 kg/m2, women with a BMI exceeding 31 kg/m2 had an RR of 0.54 (95% CI: 0.34, 0.85). In postmenopausal women, the RRs did not increase further when BMI exceeded 28 kg/m2; the RR for these women was 1.26 (95% CI: 1.09, 1.46). The authors found little evidence for interaction with other breast cancer risk factors. Their data indicate that height is an independent risk factor for postmenopausal breast cancer; in premenopausal women, this relation is less clear. The association between BMI and breast cancer varies by menopausal status. Weight control may reduce the risk among postmenopausal women.

Lack of effect of a high-fiber cereal supplement on the recurrence of colorectal adenomas. Phoenix Colon Cancer Prevention Physicians' Network

BACKGROUND

The risks of colorectal cancer and adenoma, the precursor lesion, are believed to be influenced by dietary factors. Epidemiologic evidence that cereal fiber protects against colorectal cancer is equivocal. We conducted a randomized trial to determine whether dietary supplementation with wheat-bran fiber reduces the rate of recurrence of colorectal adenomas.

METHODS

We randomly assigned 1429 men and women who were 40 to 80 years of age and who had had one or more histologically confirmed colorectal adenomas removed within three months before recruitment began to a supervised program of dietary supplementation with either high amounts (13.5 g per day) or low amounts (2 g per day) of wheat-bran fiber. The primary end point was the presence or absence of new adenomas at the time of follow-up colonoscopy. Subjects and physicians, including colonoscopists, were unaware of the group assignments.

RESULTS

Of the 1303 subjects who completed the study, 719 had been randomly assigned to the high-fiber group and 584 to the low-fiber group. The median times from randomization to the last follow-up colonoscopy were 34 months in the high-fiber group and 36 months in the low-fiber group. By the time of the last follow-up colonoscopy, at least one adenoma had been identified in 338 subjects in the high-fiber group (47.0 percent) and in 299 subjects in the low-fiber group (51.2 percent). The multivariate adjusted odds ratio for recurrent adenoma in tile high-fiber group, as compared with the low-fiber group, was 0.88 (95 percent confidence interval, 0.70 to 1.11; P=0.28), and the relative risk of recurrence according to the number of adenomas, in the high-fiber group as compared with the low-fiber group, was 0.99 (95 percent confidence interval, 0.71 to 1.36; P=0.93).

CONCLUSIONS

As used in this study, a dietary supplement of wheat-bran fiber does not protect against recurrent colorectal adenomas.

While a phobic waits: regional brain electrical and autonomic activity in social phobics during anticipation of public speaking

BACKGROUND

Recent studies have highlighted the role of right-sided anterior temporal and prefrontal activation during anxiety, yet no study has been performed with social phobics that assesses regional brain and autonomic function. This study compared electroencephalograms (EEGs) and autonomic activity in social phobics and controls while they anticipated making a public speech.

METHODS

Electroencephalograms from 14 scalp locations, heart rate, and blood pressure were recorded while 18 DSM-IV social phobics and 10 controls anticipated making a public speech, as well as immediately after the speech was made. Self-reports of anxiety and affect were also obtained.

RESULTS

Phobics showed a significantly greater increase in anxiety and negative affect during the anticipation condition compared with controls. Heart rate was elevated in the phobics relative to the controls in most conditions. Phobics showed a marked increase in right-sided activation in the anterior temporal and lateral prefrontal scalp regions. These heart rate and EEG changes together accounted for > 48% of the variance in the increase in negative affect during the anticipation phase.

CONCLUSIONS

These findings support the hypothesis of right-sided anterior cortical activation during anxiety and indicate that the combination of EEG and heart rate changes during anticipation account for substantial variance in reported negative affect.

Does nutritionist review of a self-administered food frequency questionnaire improve data quality?

OBJECTIVE

This study sought to evaluate the benefit of utilizing a nutritionist review of a self-administered food frequency questionnaire (FFQ), to determine whether accuracy could be improved beyond that produced by the self-administered questionnaire alone.

DESIGN

Participants randomized into a dietary intervention trial completed both a FFQ and a 4-day food record (FR) at baseline before entry into the intervention. The FFQ was self-administered, photocopied and then reviewed by a nutritionist who used additional probes to help complete the questionnaire. Both the versions before nutritionist review and after nutritionist review - were individually compared on specific nutrients to the FR by means, correlations and per cent agreement into quintiles.

SETTINGS AND SUBJECTS

Three hundred and twenty-four people, a subset of participants from the Polyp Prevention Trial - a randomized controlled trial examining the effect of a low-fat, high-fibre, high fruit and vegetable dietary pattern on the recurrence of adenomatous polyps - were recruited from clinical centres at the University of Utah, University of Buffalo, Memorial Sloan Kettering Cancer Center in New York and Kaiser Permanente Medical Program in Oakland.

RESULTS

Reviewing the FFQ increased correlations with the FR for every nutrient, and per cent agreement into quintiles for all nutrients except calcium. Energy was underestimated in both versions of the FFQ but to a lesser degree in the version with review.

CONCLUSIONS

One must further evaluate whether the increases seen with nutritionist review of the FFQ will enhance our ability to predict diet-disease relationships and whether it is cost-effective when participant burden and money spent utilizing trained personnel are considered.

Marijuana use and increased risk of squamous cell carcinoma of the head and neck

Marijuana is the most commonly used illegal drug in the United States. In some subcultures, it is widely perceived to be harmless. Although the carcinogenic properties of marijuana smoke are similar to those of tobacco, no epidemiological studies of the relationship between marijuana use and head and neck cancer have been published. The relationship between marijuana use and head and neck cancer was investigated by a case-control study of 173 previously untreated cases with pathologically confirmed diagnoses of squamous cell carcinoma of the head and neck and 176 cancer-free controls at Memorial Sloan-Kettering Cancer Center between 1992 and 1994. Epidemiological data were collected by using a structured questionnaire, which included history of tobacco smoking, alcohol use, and marijuana use. The associations between marijuana use and head and neck cancer were analyzed by Mantel-Haenszel methods and logistic regression models. Controlling for age, sex, race, education, alcohol consumption, pack-years of cigarette smoking, and passive smoking, the risk of squamous cell carcinoma of the head and neck was increased with marijuana use [odds ratio (OR) comparing ever with never users, 2.6; 95% confidence interval (CI), 1.1-6.6]. Dose-response relationships were observed for frequency of marijuana use/day (P for trend <0.05) and years of marijuana use (P for trend <0.05). These associations were stronger for subjects who were 55 years of age and younger (OR, 3.1; 95% CI, 1.0-9.7). Possible interaction effects of marijuana use were observed with cigarette smoking, mutagen sensitivity, and to a lesser extent, alcohol use. Our results suggest that marijuana use may increase the risk of head and neck cancer with a strong dose-response pattern. Our analysis indicated that marijuana use may interact with mutagen sensitivity and other risk factors to increase the risk of head and neck cancer. The results need to be interpreted with some caution in drawing causal inferences because of certain methodological limitations, especially with regard to interactions.

Prevalence and determinants of alcohol-related problems

In this study, we sought to determine what factors, in addition to alcohol consumption, were the best predictors of social and physical alcohol-related problems. Variables examined as possible predictors of problems included circumstances under which people drink, feelings of alienation, and religious affiliation. Data for this study were collected continually from 1984 to 1989 using a random telephone survey of 2094 New York State residents aged 18 or older; the study sample was comprised of the 1076 who had consumed alcohol in the previous 30 days. Stepwise regression analyses examined the main effects of all possible predictors of problems while controlling for alcohol consumption. Forced-entry regressions examined interaction effects of problem predictors while controlling for basic demographics. Drinking with breakfast, smoking marijuana, and drinking in bars alone were all significant predictors of more problems. This suggests that problems are associated with an aberrant lifestyle (i.e., different from a typical lifestyle), although it makes no assumption about motivations. Further investigation of this subject area is warranted to ascertain which population subgroups are the most vulnerable to alcohol-related problems and to guide the design of prevention programs.

Risk factors for Ki-ras protooncogene mutation in sporadic colorectal adenomas

The Ki-ras protooncogene frequently is mutated in colorectal adenocarcinomas, but the etiology of this molecular event is uncertain. We investigated the association between variables known or suspected to be related to risk for colorectal cancer and the occurrence of Ki-ras mutations in colorectal adenomas. This study was conducted among 678 male and female participants, 40-80 years of age, enrolled in a phase III trial testing the effects of a wheat bran fiber supplement on adenoma recurrence. Exposure information on the risk factors of interest was assessed through self-administered questionnaires. Mutations in codons 12 and 13 of the Ki-ras protooncogene were analyzed in baseline adenomas 0.5 cm or larger by PCR amplification followed by direct sequencing. Eighteen percent (120 of 678) of the participants had one or more adenoma(s) with Ki-ras mutations. A higher risk of Ki-ras mutations was associated with increasing age and a lower intake of total folate. The odds ratio (OR) for Ki-ras mutations for individuals >72 years of age was 1.98 [95% confidence interval (CI) = 1.19-3.27; P for trend = 0.008] compared with those less than 65 years of age. Compared with individuals in the lower tertile of total folate, those in the upper tertile had an approximately 50% lower risk of having Ki-ras mutation-positive adenomas (OR = 0.52; 95% CI = 0.30-0.88; P for trend = 0.02). There was a suggestion of a stronger inverse association of total folate with G-->T transversions (OR = 0.41; 95% CI = 0.20-0.87) than G-->A transitions (OR = 0.61; 95% CI = 0.31-1.21), although the CIs for the associations overlap. The results of these analyses suggest that the protective effect of folate in colon cancer observed in published studies may be mediated through folate's effect on Ki-ras mutations.

Alcohol dehydrogenase 3 genotype modification of the association of alcohol consumption with breast cancer risk

OBJECTIVES

Because alcohol dehydrogenase 3 (ADH3) is rate-limiting in alcohol oxidation and is polymorphic, we examined ADH3 genotype in relation to alcohol intake and breast cancer risk.

METHODS

We conducted a case-control study among Caucasian women aged 40-85 with incident, pathologically confirmed breast cancer and controls, frequency-matched on age and county. Queries included alcohol intake in the past 20 years. Genomic DNA was genotyped for the exon VIII ADH polymorphism by PCR followed by restriction enzyme digestion. Computation of odds ratios (OR) and 95% confidence intervals (CI) was by unconditional logistic regression.

RESULTS

We found increased risk among pre- (OR 2.3, 95%, CI 1.2-4.3) but not postmenopausal women (OR 1.1, 95% CI 0.7-1.7) associated with ADH3(1-1) compared to ADH3(1-2) and ADH3(2-2) genotypes. Risk was increased for premenopausal women with the ADH3(1-1) genotype and alcohol intake above the median (OR 3.6, 95% CI 1.5-8.8) compared to lighter drinkers with the ADH3(2-2) or ADH3(1-2) genotypes. ORs were close to null for premenopausal women in other drinking and genotype groups and for postmenopausal women categorized by genotype and alcohol consumption.

CONCLUSION

Among premenopausal women there may be a group more genetically susceptible to an alcohol consumption effect on breast cancer risk.

Reliability and validity of a self-administered food frequency questionnaire in a chemoprevention trial of adenoma recurrence

Various chemoprevention trials have assessed dietary intake by means of food frequency questionnaires. However, it is important to assess the degree to which such questionnaires can measure diet. We conducted reproducibility and validity analyses of our Arizona Food Frequency Questionnaire (AFFQ) in our recently completed, randomized, Phase III chemoprevention trial testing the effects of a wheat bran fiber supplement on colorectal adenoma recurrence. A total of 139 individuals provided a baseline and year 1 AFFQ and a set of 4-day dietary records collected over a period of 1 month. The reproducibility analyses of the AFFQ administered 1 year apart showed a mean intraclass correlation of 0.54 for unadjusted nutrients and 0.48 for energy-adjusted nutrients. The relative validity of the AFFQ, as compared with the average of the 4-day diet records, showed a mean deattenuated correlation of 0.49 (range, 0.22-0.65) for the baseline AFFQ and 0.49 (range, 0.25-0.67) for the year 1 AFFQ. When data from both AFFQs were combined and compared with the diet records, there was a slight improvement in the overall deattenuated correlations (mean, 0.56; range, 0.33-0.71). The correlations we observed for macro- and micronutrient intake were within the overall range of those reported in the literature. Reliability and validity studies of dietary instruments are feasible in the setting of a chemoprevention trial and should be conducted when the instrument's performance has not been previously assessed in the target population.

Helicobacter pylori infection on the risk of stomach cancer and chronic atrophic gastritis

Helicobacter pylori infection is associated with gastric adenocarcinoma. However, the mechanisms of this interaction are still unclear. This study was conducted to explore the effects of H. pylori infection on early and late stage gastric carcinogenesis. This study included 134 patients with adenocarcinoma of the stomach (ACS), 67 patients with chronic atrophic gastritis (CAG), and 65 normal controls recruited at Memorial Sloan-Kettering Cancer Center (MSKCC) from November 1, 1992 to November 1, 1994. Epidemiologic data were collected by a modified National Cancer Institute Health Habits History Questionnaire. H. pylori infection was diagnosed by pathological evaluation. Risk factors were analyzed using logistic regression. The odds ratio (OR) associated with H. pylori infection was 10.4 [95% confidence interval (CI): 2.6-41.6] for CAG and 11.2 (95% CI: 2.5-50.3) for gastric cancer in comparison with normal controls, with adjustment for pack-years of smoking, alcohol drinking, body mass index, total caloric intake, dietary fat and fiber intake, and Barrett's esophagus. But H. pylori infection was not associated with risk of stomach cancer when patients with stomach cancer were compared with patients with CAG (OR = 0.6, 95% CI: 0.3-1.3) after controlling for potential confounding variables. This association was persistent when only patients with both gastric cancer and chronic gastritis were considered as cases and patients with CAG were considered as controls (OR = 0.7, 95% CI: 0.3-2.0) in the multivariate analysis. Our results suggest that H. pylori infection may be involved in the early stage of development of CAG, but not in the development of stomach cancer from CAG, and indicate that strategies for prevention of stomach cancer should target the early stage to eliminate H. pylori infection in high-risk populations.

Recent alcohol intake as estimated by the Health Habits and History Questionnaire, the Harvard Semiquantitative Food Frequency Questionnaire, and a more detailed alcohol intake questionnaire

Epidemiologic studies often rely on food frequency questionnaires (FFQs) to collect information on alcoholic beverage intake. However, estimation of alcohol intake using FFQs may be of some concern because of limited questions concerning alcohol intake. The authors compared estimates of alcohol intake during the 12-24 months prior to interview obtained from the Health Habits and History Questionnaire and the Harvard Semiquantitative Food Frequency Questionnaire with those from a more extensive alcohol questionnaire, the Drinking Pattern Questionnaire, among 133 healthy subjects (75 men, 58 women) aged 35-73 years, residents of western New York State. Data were collected in 1995 during two separate interviewer-administered computer-assisted interviews conducted approximately 2 weeks apart. For each questionnaire, average daily ounces (1 oz = 30 ml) of alcohol intake from alcoholic beverages were calculated as the product of the reported beverage-specific drink size (ounces) and the average daily frequency of intake multiplied by a factor representing the percentage of alcohol provided by each beverage. Estimates of total alcohol and liquor intake, but not of beer and wine intake, tended to be higher for the Drinking Pattern Questionnaire compared with the FFQs. Spearman's correlation coefficients ranged from 0.69 to 0.84. These results suggest that although the Drinking Pattern Questionnaire produced higher estimates than either FFQ, both FFQs provide a reasonable ranking of participants' alcohol intake.

Mismeasurement and the resonance of strong confounders: correlated errors

Confounding in epidemiology, and the limits of standard methods of control for an imperfectly measured confounder, have been understood for some time. However, most treatments of this problem are based on the assumption that errors of measurement in confounding and confounded variables are independent. This paper considers the situation in which a strong risk factor (confounder) and an inconsequential but suspected risk factor (confounded) are each measured with errors that are correlated; the situation appears especially likely to occur in the field of nutritional epidemiology. Error correlation appears to add little to measurement error as a source of bias in estimating the impact of a strong risk factor: it can add to, diminish, or reverse the bias induced by measurement error in estimating the impact of the inconsequential risk factor. Correlation of measurement errors can add to the difficulty involved in evaluating structures in which confounding and measurement error are present. In its presence, observed correlations among risk factors can be greater than, less than, or even opposite to the true correlations. Interpretation of multivariate epidemiologic structures in which confounding is likely requires evaluation of measurement error structures, including correlations among measurement errors.

Physical activity, body mass index, and prostaglandin E2 levels in rectal mucosa

BACKGROUND

Evidence suggests a relationship between prostaglandin levels in colonic mucosa and risk of colon cancer. Physical inactivity and a higher body mass index (BMI; weight in kilograms divided by [height in meters]2) have been consistently shown to increase risk of this cancer. We investigated whether higher levels of leisure-time physical activity or a lower BMI was associated with lower concentrations of prostaglandin E2 (PGE2) in rectal mucosa.

METHODS

This study was conducted in 41 men and 22 women, 42-78 years of age, with a history of polyps, who participated in a randomized clinical trial testing the effects of piroxicam on rectal mucosal PGE2 levels. An [125I]PGE2 radioimmunoassay kit was used to determine PGE2 levels in samples of extracted rectal mucosa collected before randomization. Leisure-time physical activity was assessed through a self-administered questionnaire collected at baseline. The reported time spent at each activity per week was multiplied by its typical energy expenditure, expressed in metabolic equivalents (METs), to yield a MET-hours per week score. A repeated measures model was used to assess the effect of BMI and physical activity as predictors of PGE2 concentration. All statistical tests were two-sided.

RESULTS

After adjustment for age, a higher BMI was associated with higher PGE2 levels (P = .001). A higher level of leisure-time physical activity was inversely associated with PGE2 concentration (P<.03). An increase in BMI from 24.2 to 28.8 kg/m2 was associated with a 27% increase in PGE2. An increase in activity level from 5.2 to 27.7 MET-hours per week was associated with a 28% decrease in PGE2.

CONCLUSIONS

Physical activity and obesity may alter the risk of colon cancer through their effects on PGE2 synthesis.

Diet and health risk: risk patterns and disease-specific associations

Whether such epidemiologic descriptors as relative risk, dose response, and threshold points convey meaningful information is often the subject of debate. Thus, using these descriptors to juxtapose the many disease-specific effects of nutritional exposures becomes problematic. In this article it is argued that epidemiologic patterns of disease-exposure associations must be interpreted in light of the profound imprecision of exposure assessment that characterizes nutritional epidemiology. In general, this imprecision leads to substantial attenuation of disease-exposure associations, such that relative risk, dose response, and the extent to which there are thresholds in disease-exposure associations can be seriously underestimated. Linking disease-specific relative risks, especially when derived from different studies with different methods of assessing exposure, is made increasingly difficult. The most critical tasks for lessening bias in these epidemiologic descriptors are first, to lessen imprecision in measuring exposures, and second, to adjust association estimates for attenuation due to measurement imprecision.

An evaluation of proposed frameworks for grouping polychlorinated biphenyl (PCB) congener data into meaningful analytic units

BACKGROUND

Polychlorinated biphenyls (PCBs) have been associated with a variety of health outcomes. Enhanced laboratory techniques can provide a relatively large number of individual PCB congeners for investigation. However, to date there are no established frameworks for grouping a large number of PCB congeners into meaningful analytic units.

METHODS

In a case-control study of serum PCB levels on breast cancer risk, measured levels of 56 PCB congener peaks were available for analysis. We considered several approaches for grouping these compounds based on 1) chlorination, 2) factor analysis, 3) enzyme induction, 4) enzyme induction and occurrence, and 5) enzyme induction, occurrence, and other toxicological aspects. The utility of a framework was based on the mechanism of biologic actions within each framework, lack of collinearity among congener groups, and frequency of detection of PCB congener groups in measured serum levels of 192 healthy postmenopausal women.

RESULTS

Most participants had detectable levels for the proposed PCB congeners groups, using degree of chlorination as a grouping framework. In addition, the previously proposed grouping approach based on enzyme induction, occurrence, and other toxicological aspects was an applicable alternative to the crude approach of grouping by degree of chlorination. Grouping these congeners with respect to P450 enzyme induction activity, and the previously proposed framework based on enzyme induction and occurrence, did not fit these data as well, because only a small proportion of participants had detectable levels for the congener groups with the greatest toxicological potential. Statistical grouping did not result in an interpretable and meaningful clustering of these exposures.

CONCLUSIONS

In these data, grouping with respect to degree of chlorination and the previously proposed framework based on enzyme induction, occurrence, and other toxicological aspects were the most useful approaches to reducing a large number of PCB congeners into meaningful analytic units. Factors affecting the utility of the proposed grouping frameworks are discussed.

Manganese superoxide dismutase (MnSOD) genetic polymorphisms, dietary antioxidants, and risk of breast cancer

Oxidative stress, resulting from the imbalance between prooxidant and antioxidant states, damages DNA, proteins, cell membranes, and mitochondria and seems to play a role in human breast carcinogenesis. Dietary sources of antioxidants (chemical) and endogenous antioxidants (enzymatic), including the polymorphic manganese superoxide dismutase (MnSOD), can act to reduce the load of oxidative stress. We hypothesized that the valine-to-alanine substitution that seems to alter transport of the enzyme into the mitochondrion, changing its efficacy in fighting oxidative stress, was associated with breast cancer risk and that a diet rich in sources of antioxidants could ameliorate the effects on risk. Data were collected in a case-control study of diet and breast cancer in western New York from 1986 to 1991. Caucasian women with incident, primary, histologically confirmed breast cancer were frequency-matched on age and county of residence to community controls. Blood specimens were collected and processed from a subset of participants in the study (266 cases and 295 controls). Using a RFLP that distinguishes a valine (V) to alanine (A) change in the -9 position in the signal sequence of the protein for MnSOD, we characterized MnSOD genotypes in relation to breast cancer risk. We also evaluated the effect of the polymorphism on risk among low and high consumers of fruits and vegetables. Premenopausal women who were homozygous for the A allele had a 4-fold increase in breast cancer risk in comparison to those with 1 or 2 V alleles (odds ratio, 4.3; 95% confidence interval, 1.7-10.8). Risk was most pronounced among women below the median consumption of fruits and vegetables and of dietary ascorbic acid and alpha-tocopherol, with little increased risk for those with diets rich in these foods. Relationships were weaker among postmenopausal women, although the MnSOD AA genotype was associated with an almost 2-fold increase in risk (odds ratio, 1.8; confidence interval, 0.9-3.6). No appreciable modification of risk by diet was detected for these older women. These data support the hypothesis that MnSOD and oxidative stress play a significant role in breast cancer risk, particularly in premenopausal women. The finding that risk was greatest among women who consumed lower amounts of dietary antioxidants and was minimal among high consumers indicates that a diet rich in sources of antioxidants may minimize the deleterious effects of the MnSOD polymorphism, thereby supporting public health recommendations for the consumption of diets rich in fruits and vegetables as a preventive measure against cancer.

Progress report: the Arizona phase III study of the effect of wheat bran fiber on recurrence of adenomatous colon polyps

A double-blind, placebo-controlled Phase III cancer prevention trial in subjects with previous resection of adenomatous colon polyps is nearing completion. The study's primary objective is to evaluate the effects of daily dietary supplementation with large (13.5 g/day) versus small (2.0 g/day) doses of wheat bran fiber for 3 years. A summary of the study design and a progress report are presented.