Risk of malignancy among patients with rheumatic conditions

Previous studies have described an increased risk of malignancy in subjects diagnosed with rheumatic conditions, most notably rheumatoid arthritis (RA). Our aim was to quantify and compare risks for site-specific malignancy among hospitalized patients with RA, osteoarthritis (OA) and other rheumatic conditions in a nationwide, population-based cohort. Subjects were identified from Scottish hospital in-patient records from 1981 to 1996 and followed up by computer linkage of the Scottish Cancer Registry and the national registry of deaths. Expected cancer incidence was calculated from national cancer rates and related to the observed incidence by the standardized incidence ratio (SIR). Among RA patients, there was an increased risk for hematopoietic [males SIR= 2.13, 95% confidence interval (CI) 1.7-2.7; females SIR = 1.76, 95% CI 1.5-2.1], lung (males SIR = 1.32, 95% CI 1.2-1.5; females SIR = 1.44, 95% CI 1.3-1.6) and prostate (SIR = 1.26, 95% CI 1.0-1.6) cancers. Reduced risk were seen for colorectal cancer (males SIR = 0.87, 95% CI 0.7-1.1; females SIR = 0.71, 95% CI 0.6-0.9) and, among females, stomach cancer (SIR = 0.70, 95% CI 0.5-1.0). The excess risk for hematopoietic cancer and the reduced risk for colorectal and stomach cancers were sustained over 10 years of follow-up. An overall decreased risk of cancer was observed for patients with OA; the greatest reductions were observed for colorectal (males SIR = 0.88, 95% CI 0.8-1.0; females SIR = 0.84, 95% CI 0.8-0.9), stomach (males SIR = 0.79, 95% CI 0.7-0.9; females SIR = 0.66, 95% CI 0.6-0.8) and lung (males SIR = 0.72, 95% CI 0.7-0.8; females SIR = 0.84, 95% CI 0.8-0.9) malignancies, with decreased risks generally still evident at 10 years of follow-up. Our results support several previous findings regarding the incidence of hematopoietic and colorectal malignancies in RA patients. In addition, we have shown a large decrease in stomach cancer among patients with OA and females with RA that warrants further investigation since it may provide clues to possible prevention strategies. To further our knowledge about the underlying mechanisms of altered risk in cancer patients with rheumatic conditions, population studies requiring primary data collection are required.     

Familial risk of colon and rectal cancer in Iceland: Evidence for different etiologic factors?

The aim of this study was to characterize the familial risk of colon and rectal cancer using 2 population-based registries in Iceland, the Icelandic Cancer Registry and a genealogy database. The standardized incidence ratio (SIR) was used to estimate the risk among relatives of colorectal cancer index cases diagnosed in Iceland over a 46-year period (1955-2000). The 2,770 colorectal cancer patients had 23,272 first-degree relatives. Among first-degree relatives, there was an increased risk of both colon (SIR 1.47, 95% confidence interval (CI) 1.34-1.62) and rectal cancer (SIR 1.24, 95% CI 1.04-1.47). An increased risk of colon cancer was observed among siblings of colon cancer patients (SIR 2.03, 95% CI 1.76-2.33), whereas no such increase was observed for parents or offspring. Furthermore, the risk of rectal cancer was only increased among brothers (SIR 2.46 95% CI 1.46-3.89) of rectal cancer patients and not among their sisters (SIR 1.0 95% CI 0.40-2.06). The added risk of colon cancer among first-degree relatives was independent of site of colon cancer in the proband. Our results confirm that family history of colorectal cancer is a risk factor for the disease. However, family history has a different association with colon cancer than with rectal cancer, suggesting that the 2 cancer types may have different etiologic factors. Our results have implications for colon and rectal cancer screening programs.     

Haemochromatosis and gastrointestinal cancer

Iron overload in patients with haemochromatosis is a strong risk factor for liver cancer, but its influence on other gastrointestinal cancer risk is unclear. The aim was to assess the relative risk of luminal gastrointestinal cancer among patients diagnosed with haemochromatosis. This population‐based, nationwide Swedish cohort study included patients with haemochromatosis in Sweden in 1965–2013. The incidence of gastrointestinal cancers was assessed through the Swedish Cancer Registry. The measure of relative risk was the standardised incidence ratio (SIR) with 95% confidence interval (CI), that is, the ratio of the observed number of gastrointestinal cancers in the haemochromatosis cohort divided by the expected number of such cancers, calculated from the entire corresponding background population of Sweden. Among 6,849 patients in the haemochromatosis cohort with up to 48 years of follow‐up, the SIRs were 3‐fold increased for oesophageal squamous cell carcinoma (SIR = 3.2, 95% CI 1.3–6.6; n = 7) and 40% increased for colon adenocarcinoma (SIR = 1.4, 95% CI 1.1–1.9; n = 54). No associations were found between haemochromatosis and the risk of adenocarcinoma of the oesophagus (SIR = 0.5, 95% CI 0.0–2.5; n = 1), stomach (SIR = 0.7, 95% CI 0.3–1.4; n = 8), small bowel (SIR = 1.2, 95% CI 0.0–6.7; n = 1) or rectum (SIR = 1.0, 95% CI 0.6–1.6; n = 21). These findings indicate that haemochromatosis increases the risk of oesophageal squamous cell carcinoma and colon adenocarcinoma, but might not influence the risk of other types of luminal gastrointestinal cancer. These findings should encourage further research examining the role of iron overload in cancer aetiology.     

Cancer incidence in patients with type 1 diabetes mellitus: a population-based cohort study in Sweden

Although patients with type 2 diabetes have elevated risks of liver, pancreatic, kidney, and endometrial cancer, little is known about the risk of cancer for patients with type 1 diabetes. We conducted a cohort study to examine cancer incidence among 29 187 patients in Sweden who were hospitalized for type 1 diabetes from 1965 through 1999. Relative risks of cancer were estimated by age-, sex- and calendar year of follow-up--adjusted standardized incidence ratios (SIRs), using data for the entire Swedish population as a reference. After excluding cancers diagnosed during the first year after hospital discharge, we observed 355 incident cases of cancer, which corresponded to a 20% increase in overall cancer incidence among type 1 diabetes patients (SIR = 1.2, 95% confidence interval [CI] = 1.0 to 1.3). Patients with type 1 diabetes had elevated risks of cancers of the stomach (SIR = 2.3, 95% CI = 1.1 to 4.1), cervix (SIR = 1.6, 95% CI = 1.1 to 2.2), and endometrium (SIR = 2.7, 95% CI = 1.4 to 4.7). Type 1 diabetes is associated with a modest excess cancer risk overall and risks of specific cancers that differ from those associated with type 2 diabetes.     

Cancer incidence in the first-degree relatives of ovarian cancer patients.

Cancer incidence was studied among 3072 first-degree relatives of 559 unselected ovarian cancer patients. Among cohort members there were 306 cancer cases. The overall cancer incidence was not increased: the standardised incidence ratio (SIR) in males was 0.9 (95% confidence interval 0.8-1.1) and in females 1.0 (0.8-1.1). The female relatives had a significantly increased risk for ovarian cancer (SIR 2.8, 1.8-4.2). The excess was attributable to sisters only (SIR 3.7, 2.3-5.7). The relative risk for ovarian cancer among sisters decreased both by increasing age of the sister and by increasing age at diagnosis of the index patient: the SIRs were 7.3 (1.5-21.4), 4.5 (1.6-9.8) and 3.1 (1.7-5.4) for sisters of index patients diagnosed in age < 45, 45-54 and 55-75 years respectively. The age dependency of the risk supports the role of genetic factors in familial ovarian cancer. Although the risk of ovarian cancer among sisters from families with breast cancer (SIR 9.2, 3.7-19.0) was significantly higher than among sisters from families with no breast cancer patients (SIR 2.9, 1.6-4.8, rate ratio 3.1, P < 0.05), the excess was not solely attributable to coaggregation of breast and ovarian cancer. Among the 27 families with two or more ovarian cancers, only sisters were affected in 24 families, which might implicate recessive inheritance or shared environmental factors influencing ovarian cancer risk in sisters.     

Conization as a marker of persistent cervical human papillomavirus (HPV) infection and risk of gastrointestinal cancer: a Danish 34-year nationwide cohort study

Purpose

Persistent cervical infection with human papillomavirus (HPV) may be a marker of poor immune function and thus associated with an increased cancer risk. HPV infection is implicated in all cases of cervical cancer, but except for anal and esophageal cancers, the association between persistent HPV infection and gastrointestinal cancer has not been investigated.

Methods

We performed a nationwide population-based cohort study of 83,008 women undergoing cervical conization between 1978 and 2011, using cervical conization as a marker of chronic HPV infection. We computed standardized incidence ratios (SIRs) as a measure of the relative risk of each cancer comparing women undergoing conization with that expected in the general population. We also calculated absolute risks.

Results

During follow-up, 988 GI cancers occurred versus 880 expected among 83,008 women followed for a median of 14.9 years, corresponding to a SIR of 1.1 (95 % CI 1.1–1.2). Risks were increased for anal (SIR 2.9; 95 % CI 2.3–3.5) and esophageal (SIR 1.5; 95 % CI 1.1–2.0) cancers, with suggested increased risks of cancers of the gallbladder and biliary tract (SIR 1.3; 95 % CI 0.90–1.8), pancreas (SIR 1.2; 95 % CI 0.97–1.4), and liver (SIR 1.1; 95 % CI 0.79–1.6). The SIRs decreased with increasing follow-up time. The risks of gastric, small intestinal, colon, or rectal cancers were not elevated. Overall, the absolute cancer risk was 0.18 % (95 % CI 0.15–0.21) after 5 years.

Conclusions

The relative risks of several gastrointestinal cancers were raised among women who underwent cervical conization for persistent HPV infection, but the absolute risks were low.     

Cancer risk in children with birth defects and in their families: a population based cohort study of 5.2 million children from Norway and Sweden

BACKGROUND: Cancer and birth defects may share factors that influence risk. A malformation may involve physiologic changes or changes in lifestyle that might affect cancer risks. METHODS: In Norway and Sweden, the population-based medical birth and cancer registries were linked to identify subsequent cancer occurrence in children with birth defects and among their parents and siblings. Altogether, 5.2 million children and their families were included. The standardized incidence ratio (SIR) served as a measure of relative risk. RESULTS: There was an increased overall cancer risk in individuals with birth defects in the two countries [SIR, 1.7; 95% confidence interval (95% CI), 1.6-1.9], and the increased risk remained into early adulthood. Individuals with malformations in the nervous system were at increased risk of developing cancer in the brain/nervous system (Norway: SIR, 58; 95% CI, 41-80; Sweden: SIR, 8.3; 95% CI, 4.0-15), individuals with Down syndrome were at an increased risk of leukemia (Norway: SIR, 36; 95% CI, 26-48; Sweden: SIR, 36; 95% CI, 28-46), and there was an increased overall cancer risk for individuals with multiple birth defects (Norway: SIR, 5.5; 95% CI, 3.3-8.7; Sweden: SIR, 3.6; 95% CI, 2.2-5.4). There was no increased overall cancer risk among mothers (SIR, 1.0; 95% CI, 1.0-1.0), fathers (SIR, 1.0; 95% CI, 0.9-1.0), and siblings (SIR, 1.0; 95% CI, 0.9-1.1) of children with birth defects. CONCLUSIONS: We observed an increased overall cancer risk in individuals with birth defects. The highest risks were seen for individuals with malformations in the nervous system, Down syndrome, and multiple defects. No increased overall cancer risk was seen among their parents or siblings.     

Family history of breast or ovarian cancer modifies the risk of secondary leukemia after breast cancer: results from a population-based study

We evaluated the impact of a family history of breast/ovarian cancer on the risk of secondary leukemia following breast cancer. At the Geneva cancer registry, we identified 4,397 patients diagnosed with invasive breast cancer between 1990 and 2004. Patients were followed up for leukemia until the end of 2005. Family history was categorized as positive in patients with >or=1 first- or second-degree relative with breast/ovarian cancer. We compared leukemia rates in patients with positive and negative family histories with those expected in the general population, generating standardized incidence ratios (SIRs). With Cox regression analysis, we calculated adjusted risks of secondary leukemia in patients with familial risks compared to those without it. Breast cancer patients had a significantly increased risk of secondary acute leukemia (SIR 3.2, 95% CI: 1.2-6.9) but not of chronic leukemia (SIR 1.6, 95% CI: 0.6-3.5). Among patients with a positive family history (n = 1.125, 25.6%), the SIRs were 5.7 (95% CI: 1.2-16.6) for acute and 5.2 (95% CI: 1.4-13.3) for chronic leukemia. Among breast cancer patients, family history was independently associated with leukemia [adjusted hazard ratio (HR(adj)) of 3.2, 95% CI: 1.1-9.2, among patient with vs. without family history]. The effect of family history was stronger for chronic leukemia (HR(adj): 11.6, 95% CI 1.3-104.7) than for acute leukemia (HR(adj) 1.6, 95% CI: 0.4-6.6). Breast cancer patients with a family history of breast/ovarian have an increased risk of secondary leukemia, both compared to the general population as well as to breast cancer patients without family histories. This excess risk is largely due to the increased risk of secondary chronic leukemia.     

Colon and rectal cancer risk after bariatric surgery in a multicountry Nordic cohort study

Obesity is a risk factor for colorectal cancer. Yet, some research indicates that weight-reducing bariatric surgery also increases colorectal cancer risk. Our study was undertaken because current evidence examining bariatric surgery and risk of colorectal cancer is limited and inconsistent. This population-based cohort study included adults with a documented obesity diagnosis in Denmark, Finland, Iceland, Norway or Sweden in 1980–2015. The incidence of colorectal cancer in participants with obesity who had and had not undergone bariatric surgery was compared to the incidence in the corresponding background population by calculating standardized incidence ratios (SIR) with 95% confidence intervals (CI). Additionally, operated and nonoperated participants with obesity were compared using multivariable Cox regression, providing hazard ratios (HR) with 95% CIs adjusted for confounders. Among 502,772 cohort participants with an obesity diagnosis, 49,931(9.9%) underwent bariatric surgery. The overall SIR of colon cancer was increased after bariatric surgery (SIR 1.56; 95% CI 1.28–1.88), with higher SIRs ≥10 years postsurgery. The overall HR of colon cancer in operated compared to nonoperated participants was 1.13 (95% CI 0.92–1.39) and 1.55 (95% CI 1.04–2.31) 10–14 years after bariatric surgery. Bariatric surgery did not significantly increase the risk of rectal cancer (SIR 1.14, 95% CI 0.83–1.52; HR 1.08, 95% CI 0.79–1.49), but the risk estimates increased with longer follow-up periods. Our study suggests that bariatric surgery is associated with an increased risk of colon cancer, while the support for an increased risk of rectal cancer was weaker.     

Cancer occurrence after cosmetic breast implantation in Denmark

Most studies on cancer incidence after breast implantation have focused on breast cancer, while the risk of cancers at other sites has been less well investigated. We examined cancer incidence among 1,653 women who underwent cosmetic breast implant surgery at private clinics of plastic surgery in Denmark and 1,736 women attending the same clinics for other reasons during the period 1973-1995. Furthermore, we updated previously reported results among 1,114 women who received implants for cosmetic indications at public hospitals. All women were followed for cancer through the Danish Cancer Registry. In comparison with the general female population, the overall standardized incidence ratio (SIR) for cancer among women who received implants in private clinics was 1.65 [95% confidence interval (CI) = 1.17-2.27]. This elevated SIR reflected increased incidence ratios for almost all major cancer sites; however, only for non-melanoma skin cancer was there an excess of more than 2 cases. No significant excess of cancer was observed among women who received implants in public hospitals (SIR = 1.10, 95% CI = 0.76-1.52) or among women attending the private clinics for other problems (SIR = 1.10, 95% CI = 0.78-1.52). The SIRs for breast cancer after breast implantation were 1.1 (95% CI = 0.5-2.2) among private clinic patients and 0.9 (95% CI = 0.4-1.7) among public hospital patients. The overall findings of these 2 implant cohorts and results from other investigations suggest that cancer risk is probably not increased among women receiving cosmetic breast implants. The inconsistent results for private clinics and public hospitals are likely related to selection bias and confounding among the private clinic patients, but our data did not permit exploration of these possibilities. Further research into the determinants of these inconsistencies is warranted.     

Risk of a new primary cancer among patients with lung cancer of different histological types

The risk of a new primary cancer (NPC) among 77548 Finnish lung cancer patients from 1953 to 1995 was analysed by the histological type of the lung cancer. The relative risks were expressed as standardised incidence ratios (SIR, ratio of the observed and expected numbers of cases). During the follow-up, 1148 NPCs were observed among men and 152 among women. After exclusion of lung cancers, the risk of NPC was elevated in both males (SIR 1.07; 95% confidence interval (CI) 1.00-1.14) and females (SIR 1.21; 95% CI 1.02-1.42). The excess was larger among lung cancer patients with small-cell carcinoma and adenocarcinoma than those with squamous-cell carcinoma. In all major histological groups of lung cancer, significant excess risks were found for cancers of the larynx (SIRs 2.94-4.25), and bladder (SIRs 2.16-2.86). Significantly elevated SIRs were also found for cancers of the stomach (SIR 1.42; 95% CI 1.12-1.76) and kidney (SIR 2.18; 95% CI 1.56-2.97) in squamous-cell carcinoma; for brain tumours (SIR 3.26; 95% CI 1.20-7.09) in small-cell carcinoma; and for cancers of the prostate (SIR 1.68; 95% CI 1.21-2.27) and thyroid (SIR 3.79; 95% CI 1.23-8.85), and brain tumours (SIR 2.34; 95% CI 1.07-4.43) in adenocarcinoma. The risk of contracting NPC at sites where the majority of tumours are adenocarcinomas was elevated among patients with adenocarcinoma of the lung, but not among squamous-cell or small-cell carcinoma patients. In adenocarcinoma, the excess risks of several smoking-related cancers tended to be somewhat lower than those in the other two histological categories. The relative risk of a NPC among patients diagnosed with lung cancer in 1985-1995 was higher than that of patients from earlier periods in all comparable follow-up categories (up to 10 years), possibly suggesting that the increased use of cytostatic drugs had increased the risk of NPC.     

Cancer incidence among marine engineers,a population-based study (Iceland)

Objectives: Marine engineers are in their occupation exposed to different chemicals, organic solvents, exhaust gases, oils, and petroleum products, and were formerly exposed to asbestos. The aim was to study the cancer pattern, with particular attention to lung and bladder cancer, in an Icelandic cohort of marine engineers, indirectly controlling for their smoking habits. Methods: A cohort of 6603 male marine engineers was followed up from 1955 to 1998, a total of 167,715 person-years. The cohort was record linked by the engineers' personal identification numbers to population-based registers containing the vital and emigration status and cancer diagnosis. Standardized incidence ratios (SIRs) were calculated for all cancers and different cancer sites in relation to different lag time and year of graduation. Information on smoking habits was obtained by administering a questionnaire to a sample of the cohort (n = 1501). Results: In the total cohort 810 cancers were observed, whereas 794 were expected (SIR 1.0, 95% CI 1.0–1.1), and significantly increased risk of stomach cancer (SIR 1.3, 95% CI 1.0–1.5) and lung cancer (SIR 1.2, 95% CI 1.0–1.5) was found. Increased risk of all cancers (SIR 1.2, 95% CI 1.1–1.3), stomach cancer (SIR 1.5, 95% CI 1.1–1.9), lung cancer (SIR 1.4, 95% CI 1.2–1.8), pleural mesothelioma (SIR 4.8, 95% CI 1.3–12.3), and urinary bladder cancer (SIR 1.3, 95% CI 1.0–1.8) were observed when a 40-year lag time was applied. The engineers' smoking habits were similar to those in a sample of the general population. The predictive value for lung cancer was 1.03. Conclusions: The increased risk for mesothelioma is possibly attributable to the previous asbestos exposure. The excess of lung cancer could also be related to asbestos exposure. The high incidence of stomach cancer, lung cancer, and bladder cancer may be related to exposure to chemical risk factors, such as oils and petroleum products, as confounding due to smoking seems to be ruled out. In the light of the limited exposure information in the present study the importance of the different occupational exposures needs to be evaluated in further studies.     

Long-term cancer risk among Swedish women with cosmetic breast implants: an update of a nationwide study

Epidemiologic evidence does not support a consistently increased cancer risk among women with cosmetic breast implants, but few studies have assessed risk beyond 15 years. Swedish women who underwent cosmetic breast implantation for the first time between January 1, 1965, and December 31, 1993 (N = 3486), were followed through December 31, 2002. Cancer incidence was ascertained through the nationwide Swedish Cancer Registry. Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated to compare cancer incidence of women with implants with women in the general population. Mean follow-up among women with breast implants was 18.4 years (range = 0.1-37.8 years). The incidence of breast cancer was below expectation (SIR = 0.7, 95% CI = 0.6 to 1.0), whereas lung cancer was above expectation (SIR = 2.2, 95% CI = 1.3 to 3.4). With respect to cancer overall and all other specific cancer sites, including brain cancer and sarcoma, non-Hodgkin lymphoma, and multiple myeloma, no statistically significantly increased or decreased SIRs were observed. Stratification by duration of follow-up revealed no statistically significantly increased or decreased SIR, with the exception of a two- to threefold excess of lung cancer among women followed for more than 15 years, which would be expected due to the high prevalence of smoking among the Swedish women with implants in our study.     

Cancer of the gastrointestinal tract and exposure to asbestos in drinking water among lighthouse keepers (Norway)

Objective Previous studies of predominantly ecological design have indicated a possible elevation of gastrointestinal cancer risk in population groups exposed to drinking water contaminated with asbestos from natural sources or asbestos–cement containing water pipes. In the present study the possible effect of ingested asbestos fibers on gastrointestinal cancer risk was investigated in an occupational group where a proportion of the employees was exposed to asbestos in their drinking water.Method A cohort of 726 lighthouse keepers first employed between 1917 and 1967 were followed up for cancer incidence from 1960 to 2002. The standardized incidence ratio (SIR) was calculated as the number of new cancer cases divided by the expected number based on five-year age and sex specific incidence rates in the general rural population of Norway. A 95% confidence interval (CI) was calculated for all SIR values assuming a Poisson distribution of the cancer cases.Results Risk of stomach cancer was elevated in the whole cohort (SIR: 1.6, CI: 1.0–2.3), in the subgroup with definite asbestos exposure (SIR: 2.5, CI: 0.9–5.5), and when the group was followed for 20 years and more after first possible exposure (SIR: 1.7, CI: 1.1–2.7). Less consistent results were found for colon cancer; SIR was 1.5 (CI: 0.9–2.2) overall, 0.8 (CI: 0.1–2.9) among the exposed, and 1.6 (CI: 1.0–2.5) twenty years and more after first possible exposure.Conclusion The results support the hypothesis of an association between ingested asbestos and gastrointestinal cancer risk in general and stomach cancer risk specifically.     

Increased risk of cancer among siblings of long-term childhood cancer survivors: a report from the childhood cancer survivor study.

We determined risk of cancer among first-degree relatives of 5-year survivors of childhood leukemia, lymphoma, central nervous system tumors, sarcomas, Wilms' tumor, and neuroblastoma. Subjects were 13,703 participants in the Childhood Cancer Survivor Study. Family history was collected on 56,759 first-degree relatives using a self-reported questionnaire. Incidence was compared with age- and sex-specific rates using the U.S. Surveillance, Epidemiology and End Results program. Siblings of the survivors had an increased risk of cancer [standardized incidence ratio (SIR), 1.5; 95% confidence interval (95% CI), 1.35-1.7]. Risk was elevated for siblings of probands of leukemia (SIR, 1.3; 95% CI, 1.0-1.6), Hodgkin's disease (SIR, 1.5; 95% CI, 1.2-1.9), non-Hodgkin's lymphoma (SIR, 1.8; 95% CI, 1.3-2.5), Wilms' tumor (SIR, 1.9; 95% CI, 1.2-3.2), soft tissue sarcoma (SIR, 1.5; 95% CI, 1.0-2.2), and bone tumors (SIR, 1.6; 95% CI, 1.2-2.2). Cancer risk was elevated in siblings (SIR, 2.4; 95% CI, 1.5-3.7) and offspring (SIR, 15.0; 95% CI, 5.3-42.9) of probands with second malignant neoplasms (SMN) compared with relatives of probands without SMNs. Siblings of probands with leukemia, Hodgkin's disease, neuroblastoma, and Wilms' tumor had elevated risks for the same malignancies. Parents had no increased risk (fathers' SIR, 0.7; 95% CI, 0.7-0.8; mothers' SIR, 0.9; 95% CI, 0.9-1.0). Seventy percent of siblings' cancers developed in adulthood. These findings suggest that familial cancer syndromes may be revealed as this cohort and family members age and with accrual of more offspring and subjects with SMNs.     

Coffee and tea consumption and cancers of the bladder, colon and rectum.

Coffee has been observed to be associated weakly or not at all with bladder cancer risk, inversely with colon cancer risk, and inconsistently with rectal cancer risk. The association between these cancers and consumption of coffee and tea was examined in a single case-control study conducted in Ontario, Canada from 1992 to 1994. A questionnaire was filled out by 927 bladder cancer cases, 991 colon cancer cases, 875 rectal cancer cases, and 2118 population controls. Although bladder cancer risk was not associated with coffee or tea, risk estimates associated with coffee among subjects who had never smoked were non-significantly increased. Colon cancer risk was inversely associated with coffee. Relative to those drinking less than 1 cup of coffee per day, the odds ratios (OR) for those drinking 1-2 cups was 0.9 (95% CI 0.8-1.1), for those drinking 3-4 cups was 0.8 (95% CI 0.7-1.0), and for those drinking 5 or more cups was 0.7 (95% CI 0.5-0.9); these ORs decreased linearly (P = 0.008). The reduced risk estimates were more pronounced with cancer of the proximal colon than the distal colon. Rectal cancer risk was not associated with either coffee or tea. Coffee consumption was observed to have a different relationship for each of the cancer sites and tea consumption was not related to any cancer site.     

Migration, socio-economic status and the risk of colorectal cancer in Italy.

To assess how the risk of cancer of the colon and rectum relates to place of birth and socio-economic status, we analysed data from an Italian case-control study. Data included 1225 cases with a recent diagnosis of cancer of the colon (ages 19-74 years), 728 cases of cancer of the rectum (ages 23-74 years) and 4154 controls (ages 19-74 years), frequency-matched with cases by age and catchment area and admitted to hospitals for a wide spectrum of acute non-neoplastic conditions. Compared with residents born in the north of Italy, migrants from the centre and south had an odds ratio (OR) of 0.7 (95% CI 0.5-0.9) for colon cancer and OR of 0.9 (95% CI 0.7-1.2) for cancer of the rectum. The inverse association of migration with colon cancer was stronger among women (OR 0.5, 95% CI 0.4-0.8) than among men (OR 0.8, 95% CI 0.6-1.1), and was independent of education and occupation. Among migrants, the direct association between education and colon cancer risk was less clear than among non-migrants. In conclusion, place of origin played an independent role in colon cancer aetiology. Results on rectal cancer were less clear, although in the same direction. Among migrants, those less susceptible to behavioural changes (e.g. women) retained most of the benefit associated with their place of origin.     

Breast cancer risk in monozygotic and dizygotic female twins: a 20-year population-based cohort study in Finland from 1976 to 1995.

This population-based study investigated the occurrence of breast cancer over a 20-year period in a cohort of monozygotic (MZ) and dizygotic (DZ) twins in Finland. Altogether, 13,176 female twins of known zygosity who were living in Finland at the end of 1975 were identified from the Finnish Twin Cohort Study and followed-up for cancer through the Finnish Cancer Registry for the years 1976-1995. Standardized incidence ratios (SIRs) were calculated, based on national cancer incidence rates. The relative risk of breast cancer for MZ twins compared to DZ twins was decreased [SIR(MZ)/SIR(DZ) ratio = 0.78; 95% confidence interval (CI), 0.58-1.0]; the decreased risk for MZ twins (SIR = 0.76; 95% CI, 0.58-1.0) accounted for this result, whereas the risk for DZ twins did not differ from the general population risk (SIR = 0.98; 95% CI, 0.84-1.1). There was no risk decrease among MZ twins in other cancers related to reproductive behavior; i.e., number of children and age at first birth seem not to explain the decreased risk of breast cancer. Our results, which are in line with earlier studies on the same topic, suggest that prenatal influences or postnatal behavioral factors may protect MZ female twins from breast cancer.