Cancer Causes & Control

Mục tiêu: Mục đích của nghiên cứu này là điều tra xem việc hấp thụ folate có liên quan đến nguy cơ phát sinh adenoma đại tràng tình cờ hay không, và mối liên hệ này có khác nhau tùy thuộc vào các kiểu gen methylenetetrahydrofolate reductase (MTHFR) hoặc có bị tác động bởi mức tiêu thụ rượu hoặc các vi chất dinh dưỡng khác trong con đường chuyển hóa folate hay không. Phương pháp: Các tác giả đã phân tích dữ liệu từ một nghiên cứu trường hợp – đối chứng dựa trên nội soi đại tràng (n = 177 trường hợp, 228 đối chứng) được thực hiện tại Bắc Carolina từ năm 1995 đến 1997. Kết quả: Tỷ lệ odds (OR) điều chỉnh đa biến so sánh giữa tertile cao nhất và thấp nhất của tổng lượng folate hấp thụ là 0.61 (Khoảng tin cậy [CI] 95% 0.35–1.05); đối với kiểu gen đa hình C677T MTHFR CT và TT so với kiểu gen CC lần lượt là 1.09 (CI: 0.71–1.66) và 0.68 (CI: 0.29–1.61); và đối với những người uống rượu nặng (>3 đồ uống/tuần) so với những người không uống rượu là 1.67 (CI: 1.00–2.81). Tỷ lệ odds điều chỉnh đa biến so sánh giữa tertile cao nhất và thấp nhất của tổng lượng folate hấp thụ theo kiểu gen MTHFR CC, CT và TT lần lượt là 0.65 (CI: 0.30–1.39), 0.57 (CI: 0.23–1.44), và 0.22 (CI: 0.02–3.19). Đối với những người ở tertile thấp nhất của lượng folate hấp thụ uống hơn ba đồ uống mỗi tuần so với những người ở tertile cao nhất của lượng folate hấp thụ và không uống rượu, OR là 6.54 (CI: 1.96–21.80). Không có bằng chứng đáng kể nào về các tương tác giữa folate với việc tiêu thụ methionine, vitamin B2, B6, hoặc B12. Kết luận: Những dữ liệu này nhất quán với các giả thuyết và phát hiện trước đó rằng việc hấp thụ folate cao hơn có thể làm giảm nguy cơ mắc các khối u đại tràng, có thể đặc biệt đúng với những người tiêu thụ nhiều rượu.

Inflammation is a process central to carcinogenesis and in particular to colorectal cancer (CRC). Previously, we developed a dietary inflammatory index (DII) from extensive literature review to assess the inflammatory potential of diet. In the current study, we utilized this novel index in the Women’s Health Initiative to prospectively evaluate its association with risk of CRC in postmenopausal women. The DII was calculated from baseline food frequency questionnaires administered to 152,536 women aged 50–79 years without CRC at baseline between 1993 and 1998 and followed through 30 September 2010. Incident CRC cases were ascertained through a central physician adjudication process. Multiple covariate-adjusted Cox proportional hazards regression models were used to estimate hazard ratios (HR) and 95 % confidence intervals (95 % CI) for colorectal, colon (proximal/distal locations), and rectal cancer risk, by DII quintiles (Q). During an average 11.3 years of follow-up, a total of 1,920 cases of CRC (1,559 colon and 361 rectal) were identified. Higher DII scores (representing a more pro-inflammatory diet) were associated with an increased incidence of CRC (HRQ5–Q1 1.22; 95 % CI 1.05, 1.43; p trend = 0.02) and colon cancer, specifically proximal colon cancer (HRQ5–Q1 1.35; 95 % CI 1.05, 1.67; p trend = 0.01) but not distal colon cancer (HRQ5–Q1 0.84; 95 % CI 0.61, 1.18; p trend = 0.63) or rectal cancer (HRQ5–Q1 1.20; 95 % CI 0.84, 1.72; p trend = 0.65). Consumption of pro-inflammatory diets is associated with an increased risk of CRC, especially cancers located in the proximal colon. The absence of a significant association for distal colon cancer and rectal cancer may be due to the small number of incident cases for these sites. Interventions that may reduce the inflammatory potential of the diet are warranted to test our findings, thus providing more information for colon cancer prevention.

Objective: To examine whether exposures to anti-inflammatory and non-narcotic analgesic drugs are associated with risk of non-Hodgkin's lymphoma (NHL). Methods: A case–control study was conducted among women living in upstate New York. The study involved 376 cases of NHL identified through the New York State Cancer Registry and 463 controls randomly selected from the Medicare beneficiary files and New York State driver's license records. Information regarding use of common medications in the past 20 years and potential confounding variables was obtained by telephone interview. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using an unconditional logistic regression model. Results: There were non-significant increases in risk associated with ever use of cortisone injections and oral cortisone (OR = 1.44 (Cl 0.98–2.11) for injections and 1.21 (CI 0.73–2.00) for oral cortisone, although there was no clear dose–response relationship with either type. On the other hand, the risk of NHL progressively increased with the frequency of use of non-steroidal anti-inflammatory and non-narcotic analgesic drugs (NSAID/NNAD) (p-value for trend 0.008). Women who used any of these medications daily for more than 10 years had an OR of 1.90 (CI 1.01–3.57), compared with those who used it less than once a month on average. The risk associated with long-term use was most pronounced for ibuprofen, intermediate for aspirin, and least for acetaminophen. Conclusions: Because the population-attributable risk associated with NSAID/NNAD use is potentially large, our results need to be verified in further epidemiologic studies.

Objectives: Elevated risks of skin cancer following high doses of ionizing radiation have long been known. Recent reports on atomic-bomb survivors indicate that nonmelanoma skin cancer can be induced at low to medium doses. We studied atomic-bomb survivors to determine the effects of radiation on specific histologic types of skin cancer and to describe the dose-response relationship. Methods: Cases of melanoma, nonmelanoma skin cancers, and Bowen's disease were ascertained between 1958 and 1987 for the 80,000 cohort members through the population-based Hiroshima and Nagasaki (Japan) tumor registries augmented by searches of other records. Results: An excess of basal cell carcinoma (n=80), with some suggestion of a non-linear dose-response, was observed. The excess risk decreased markedly as age at exposure increased, and there was no evidence for an interaction between ionizing and ultraviolet radiation. No dose-response was found for squamous cell carcinoma (n=69). The excess relative risk point-estimates were large, but statistically nonsignificant for both melanoma (n=10) and Bowen's disease (n=26). Conclusions: The basal layer of the epidermis appears to be quite sensitive to radiation carcinogenesis, particularly at a young age. The suprabasal layer seems to be more resistant, as shown by the lack of an association for squamous cell carcinomas.

To explore prenatal risk factors that are common to testicular cancer and cryptorchidism, two parallel case-control studies were conducted in Denmark. Information about characteristics of the mother, the pregnancy, and the birth were obtained from the mothers of cases and controls, using a mailed self-administered questionnaire. A maternal age above 30 years was associated with odds ratios (OR) of 1.9 (95 percent confidence interval [CI]= 1.2-3.0) for cryptorchidism and 2.0 (CI = 1.2-3.6) for testicular seminoma; the latter effect was particularly high when the boy was the first child of the mother (OR = 4.1, CI = 1.1-14.6). Birth weights below 3,000 g or above4,000 g were associated with increased risks of testicular cancer, with OR sup to 2.6 (CI = 1.1-5.9) for birth weight below 2,500 g. For cryptorchidism, there was a monotonous trend in the OR from 0.4 in birth weights above 4,500 g to 2.3 in birth weights below 2,500 g. The association between cryptorchidism and testicular cancer was not attenuated by adjustment for maternal age and birthweight, indicating that all three variables are independent risk factors for testicular cancer. With the exception of high maternal age, which consistently is associated more strongly with seminoma than withnon-seminoma, it remains most likely that seminoma and non-seminoma have similar causes.

Objective: Some epidemiological studies suggest that diets high in fat, saturated fat, or cholesterol are associated with increased risk of lung cancer. Since meat consumption is correlated with the intake of saturated fat and cholesterol, we investigated the role of meat intake and cooking practices in relation to lung cancer risk. Methods: A population-based case-control study of both non-smoking and smoking women was conducted in Missouri. A 100-item food frequency questionnaire (FFQ) with detailed questions on meat consumption was completed by 593 cases and 623 frequency matched controls. We estimated quantity of meat eaten (grams/day) according to cooking method, and doneness level. Odds ratios (ORs) and 95% confidence intervals (C.I.s) were calculated using logistic regression. Multivariate models included age, packyears of smoking, body mass index (BMI, kg/m2), education, and intake of calories, fat, fruit/fruit juices, and vegetables. Results: When comparing 90th and 10th percentiles, lung cancer risk increased for total meat consumption (OR=1.6, C.I. 1.1-2.4), red meat (OR=1.8, C.I., 1.2-2.7), well-done red meat (OR=1.5, C.I.s, 1.1-2.1) and fried red meat (OR=1.5, C.I., 1.1-2.0). The odds ratios for 5th vs. 1st quintiles using the categorical variable for well-done red meat and fried red meat were essentially the same as reported above; however, the increase in risk was associated mainly with the 5th quintile. The ORs for a 10-gram increase in consumption were, 1.04 for total meat, 1.06 for red meat, 1.08 for well done red meat, and 1.09 for fried red meat. Conclusions: Consumption of red meat, especially fried and/or well-done red meat, was associated with increased risk of lung cancer.

Inconsistent results for coffee consumption and bladder cancer (BC) risk have been shown in epidemiological studies. This research aims to increase the understanding of the association between coffee consumption and BC risk by bringing together worldwide case–control studies on this topic. Data were collected from 13 case–control comprising of 5,911 cases and 16,172 controls. Pooled multivariate odds ratios (ORs), with corresponding 95% confidence intervals (CIs), were obtained using multilevel logistic regression models. Furthermore, linear dose–response relationships were examined using fractional polynomial models. No association of BC risk was observed with coffee consumption among smokers. However, after adjustment for age, gender, and smoking, the risk was significantly increased for never smokers (ever vs. never coffee consumers: ORmodel2 1.30, 95% CI 1.06–1.59; heavy (> 4 cups/day) coffee consumers vs. never coffee consumers: ORmodel2 1.52, 95% CI 1.18–1.97, p trend = 0.23). In addition, dose–response analyses, in both the overall population and among never smokers, also showed a significant increased BC risk for coffee consumption of more than four cups per day. Among smokers, a significant increased BC risk was shown only after consumption of more than six cups per day. This research suggests that positive associations between coffee consumption and BC among never smokers but not smokers.

Side effects as a result of breast cancer treatment may have a lasting detrimental impact on quality of life. Exercise has been shown to be an effective intervention in post-treatment care. This study aimed to gain a better understanding of breast cancer treatment-related side effects through identifying potential patient characteristic associations, including current levels of exercise. Four hundred and thirty-two breast cancer patients completed an online survey covering their treatment and demographic background, current exercise levels, and self-reported treatment side effects. Side effects were considered in a binary logistic regression against age, surgery, currently undergoing treatment, and exercise levels to ascertain significant relationships (p < 0.05) and associative values (Odds Ratio). Lumpectomy patients were less likely to report aching muscles (OR 0.61, 95 % CI 0.39–0.96), hot flushes (OR 0.60, 95 % CI 0.38–0.96), and weight gain (OR 0.59, 95 % CI 0.38–0.92) than mastectomy patients. Women currently undergoing treatment were more likely to report hot flushes (OR 3.77, 95 % CI 2.34–6.08), aching muscles (OR 1.62, 95 % CI 1.02–2.57), and weight gain (OR 1.89, 95 % CI 1.19–2.99) than women finished treatment. Sedentary women were more likely to experience shoulder limitations (OR 1.77, 95 % CI 1.14–2.77), muscular chest wall pain (OR 1.69, 95 % CI 1.07–2.65), weight gain (OR 2.29, 95 % CI 1.44–3.64), lymphedema (OR 1.68, 95 % CI 1.04–2.71), and breathlessness (OR 2.30 95 % CI 1.35–3.92) than their physically active counterparts. Patient characteristics may inform interventions to improve care post-breast cancer treatment. Sufficient levels of exercise were consistently associated fewer side effects and should be encouraged.

Objectives: Some epidemiologic studies suggest that adolescent physical activity reduces subsequent breast cancer risk. To examine this question further, we analyzed data on physical activity at age 12 that had been collected as part of the Carolina Breast Cancer Study (CBCS). Methods: The CBCS is a population-based, case-control study of 527 white and 337 African-American cases and 790 controls, frequency-matched on age and race. Respondents were asked whether, and to what extent, they engaged in four specific activities at age 12 (walking to school, biking to school, competitive training, performing vigorous household chores). Results: Women who reported participation in any of the four activities had a modest reduction in breast cancer risk (odds ratio (OR): 0.8, 95% confidence interval (CI): 0.6–1.0). Using an index measuring approximate number of activity episodes per week, analyses revealed modest inverse relationships for nearly all levels of activity relative to no reported activity; a weighting of the index by metabolic equivalent scores produced similar results. Conclusions: Our findings support the hypothesis that adolescent physical activity may protect against adult breast cancer, even at moderate levels.