Estimating the global cancer incidence and mortality in 2018: GLOBOCAN sources and methods.

Estimates of the worldwide incidence and mortality from 36 cancers and for all cancers combined for the year 2018 are now available in the GLOBOCAN 2018 database, compiled and disseminated by the International Agency for Research on Cancer (IARC). This paper reviews the sources and methods used in compiling the cancer statistics in 185 countries. The validity of the national estimates depends upon the representativeness of the source information, and to take into account possible sources of bias, uncertainty intervals are now provided for the estimated sex- and site-specific all-ages number of new cancer cases and cancer deaths. We briefly describe the key results globally and by world region. There were an estimated 18.1 million (95% UI: 17.5-18.7 million) new cases of cancer (17 million excluding non-melanoma skin cancer) and 9.6 million (95% UI: 9.3-9.8 million) deaths from cancer (9.5 million excluding non-melanoma skin cancer) worldwide in 2018.

Cancer incidence and mortality patterns in Europe: Estimates for 40 countries and 25 major cancers in 2018.

INTRODUCTION: Europe contains 9% of the world population but has a 25% share of the global cancer burden. Up-to-date cancer statistics in Europe are key to cancer planning. Cancer incidence and mortality estimates for 25 major cancers are presented for the 40 countries in the four United Nations-defined areas of Europe and for Europe and the European Union (EU-28) for 2018. METHODS: Estimates of national incidence and mortality rates for 2018 were based on statistical models applied to the most recently published data, with predictions obtained from recent trends, where possible. The estimated rates in 2018 were applied to the 2018 population estimates to obtain the estimated numbers of new cancer cases and deaths in Europe in 2018. RESULTS: There were an estimated 3.91 million new cases of cancer (excluding non-melanoma skin cancer) and 1.93 million deaths from cancer in Europe in 2018. The most common cancer sites were cancers of the female breast (523,000 cases), followed by colorectal (500,000), lung (470,000) and prostate cancer (450,000). These four cancers represent half of the overall burden of cancer in Europe. The most common causes of death from cancer were cancers of the lung (388,000 deaths), colorectal (243,000), breast (138,000) and pancreatic cancer (128,000). In the EU-28, the estimated number of new cases of cancer was approximately 1.6 million in males and 1.4 million in females, with 790,000 men and 620,000 women dying from the disease in the same year. CONCLUSION: The present estimates of the cancer burden in Europe alongside a description of the profiles of common cancers at the national and regional level provide a basis for establishing priorities for cancer control actions across Europe. The estimates presented here are based on the recorded data from 145 population-based cancer registries in Europe. Their long established role in planning and evaluating national cancer plans on the continent should not be undervalued.

Cutaneous melanoma in France in 2015 attributable to solar ultraviolet radiation and the use of sunbeds.

BACKGROUND: Exposure to solar ultraviolet radiation (UVR) and the use of UV-emitting tanning devices are associated with cutaneous malignant melanoma occurrence. OBJECTIVE: The aim of this study was to quantify the proportion and number of melanoma cases attributable to solar UVR exposure and sunbed use in France in 2015. METHODS: Population attributable fractions (PAFs) and numbers of melanoma cases attributable to solar UVR exposure were estimated by age and sex using the incidence rates of a 1903 birth cohort as the primary reference. Further analyses were performed using the following: (i) contemporary melanoma incidence rates in low-incidence regions within France and (ii) national melanoma incidence rates for the year 1980, as additional references. Assuming a 15-year lag period, PAF and melanoma cases attributable to sunbed use were calculated using prevalence estimates from a cross-sectional population survey and published relative risk estimates. RESULTS: In 2015, an estimated 10 340 melanoma cases diagnosed in French adults were attributable to solar UVR exposure, corresponding to 83% of all melanomas and 3% of all cancer cases in that year. PAFs for melanoma were highest in the youngest age group (30-49 years) and higher in men than in women (89% vs. 79%). A total of 382 melanoma cases occurring in French adults in 2015 were attributed to the use of sunbeds, equivalent to 1.5% and 4.6% of all melanoma cases in men and women, respectively. CONCLUSIONS: A considerable proportion of melanoma cases in France in 2015 were attributable to solar UVR exposure, suggesting that targeted prevention strategies need to be implemented.

Central obesity increases risk of breast cancer irrespective of menopausal and hormonal receptor status in women of South Asian Ethnicity.

BACKGROUND: Current evidence suggests that the relationship between obesity and breast cancer (BC) risk may vary between ethnic groups. METHODS: A total of 1633 BC cases and 1504 controls were enrolled in hospital-based case-control study in Mumbai, India, from 2009 to 2013. Along with detailed questionnaire, we collected anthropometric measurements on all participants. We used unconditional logistic regression models to estimate odds ratios (ORs) and 95% confidence interval (CI) for BC risk associated with anthropometry measurements, stratified on tumour subtype and menopausal status. RESULTS: Waist-to-hip ratio (WHR) of ≥0.95 was strongly associated with risk of BC compared to WHR ≤0.84 in both premenopausal (OR = 4.3; 95% CI: 2.9-6.3) and postmenopausal women (OR = 3.4; 95% CI: 2.4-4.8) after adjustment for body mass index (BMI). Premenopausal women with a BMI ≥30 were at lower risk compared to women with normal BMI (OR = 0.5; 95% CI: 0.4-0.8). A similar protective effect was observed in women who were postmenopausal for <10 years (OR = 0.6; 95% CI: 0.4-0.9) but not in women who were postmenopausal for ≥10 years (OR = 1.8; 95% CI: 1.1-3.3). Overweight and obese women (BMI: 25-29.9 and ≥ 30 kg/m(2), respectively) were at increased BC risk irrespective of menopausal status if their WHR ≥0.95. Central obesity (measured in terms of WC and WHR) increased the risk of both premenopausal and postmenopausal BCs irrespective of hormone receptor (HR) status. CONCLUSIONS: Central obesity appears to be a key risk factor for BC irrespective of menopausal or HR status in Indian women with no history of hormone replacement therapy.

The impact of cigarette smoking on life expectancy between 1980 and 2010: a global perspective.

INTRODUCTION: Tobacco smoking is among the leading causes of preventable mortality worldwide. We assessed the impact of smoking on life expectancy worldwide between 1980 and 2010. METHODS: We retrieved cause-specific mortality data from the WHO Mortality Database by sex, year and age for 63 countries with high or moderate quality data (1980-2010). Using the time of the peak of the smoking epidemic by country, relative risks from the three waves of the Cancer Prevention Study were applied to calculate the smoking impact ratio and population attributable fraction. Finally, we estimated the potential gain in life expectancy at age 40 if smoking-related deaths in middle age (40-79 years) were eliminated. RESULTS: Currently, tobacco smoking is related to approximately 20% of total adult mortality in the countries in this study (24% in men and 12% in women). If smoking-related deaths were eliminated, adult life expectancy would increase on average by 2.4 years in men (0.1 in Uzbekistan to 4.8 years in Hungary) and 1 year in women (0.1 in Kyrgyzstan to 2.9 years in the USA). The proportion of smoking-related mortality among men has declined in most countries, but has increased in the most populous country in the world, that is, China from 4.6% to 7.3%. Increases in the impact of tobacco on life expectancy were observed among women in high-income countries. CONCLUSIONS: Recent trends indicate a substantial rise in the population-level impact of tobacco smoking on life expectancy in women and in middle-income countries. High-quality local data are needed in most low-income countries.

Cancer Incidence in Five Continents: Inclusion criteria, highlights from Volume X and the global status of cancer registration.

Cancer Incidence in Five Continents (CI5), a longstanding collaboration between the International Agency for Research on Cancer and the International Association of Cancer Registries, serves as a unique source of cancer incidence data from high-quality population-based cancer registries around the world. The recent publication of Volume X comprises cancer incidence data from 290 registries covering 424 populations in 68 countries for the registration period 2003-2007. In this article, we assess the status of population-based cancer registries worldwide, describe the techniques used in CI5 to evaluate their quality and highlight the notable variation in the incidence rates of selected cancers contained within Volume X of CI5. We also discuss the Global Initiative for Cancer Registry Development as an international partnership that aims to reduce the disparities in availability of cancer incidence data for cancer control action, particularly in economically transitioning countries, already experiencing a rapid rise in the number of cancer patients annually.

Global patterns of cardia and non-cardia gastric cancer incidence in 2012.

OBJECTIVE: Globally, gastric cancer incidence shows remarkable international variation and demonstrates distinct characteristics by the two major topographical subsites, cardia (CGC) and non-cardia (NCGC). Because global incidence estimates by subsite are lacking, we aimed to describe the worldwide incidence patterns of CGC and NCGC separately. DESIGN: Using Cancer Incidence in Five Continents Volume X (CI5X), we ascertained the proportions of CGC and NCGC by country, sex and age group (<65 and ≥65 years). These derived proportions were applied to GLOBOCAN 2012 data to estimate country-specific age-standardised CGC and NCGC incidence rates (ASR). Regional proportions were used to estimate rates for countries not included in CI5X. RESULTS: According to our estimates, in 2012, there were 260,000 cases of CGC (ASR 3.3 per 100,000) and 691,000 cases of NCGC (ASR 8.8) worldwide. The highest regional rates of both gastric cancer subsites were in Eastern/Southeastern Asia (in men, ASRs: 8.7 and 21.7 for CGC and NCGC, respectively). In most countries NCGC occurred more frequently than CGC with an average ratio of 2:1; however, in some populations where NCGC incidence rates were lower than the global average, CGC rates were similar or higher than NCGC rates. Men had higher rates than women for both subsites but particularly for CGC (male-to-female ratio 3:1). CONCLUSIONS: This study has, for the first time, quantified global incidence patterns of CGC and NCGC providing new insights into the global burden of these cancers. Country-specific estimates are provided; however, these should be interpreted with caution. This work will support future investigations across populations.

Association of change in physical activity and body weight with quality of life and mortality in colorectal cancer: a systematic review and meta-analysis.

PURPOSE: A systematic review and a meta-analysis were performed to assess the associations between change over time in physical activity and weight and quality of life and mortality in colorectal cancer patients. METHODS: The PubMed, Embase, and Cochrane Central Register of Controlled Trials databases were searched for English language articles published between January 1, 1990 and October 7, 2013. These articles reported results for changes in physical activity and body weight, assessed at pre- to post-diagnosis or at post-diagnosis only. A random effects model was used to analyze pooled quality of life and mortality estimates. RESULTS: Seven eligible studies were identified and analyzed. Increased physical activity was associated with higher overall quality of life scores (N = 3 studies; standardized mean difference (SMD) = 0.74, 95 % confidence interval (CI) = 0.66-0.82), reduced disease-specific mortality risk (hazard ratio (HRpooled) = 0.70, 95 % CI = 0.55-0.85), and reduced overall mortality (HRpooled = 0.75, CI = 0.62-0.87) (N = 2 studies). Weight gain was not associated with disease-specific (HRpooled = 1.02, CI = 0.84-1.20) or overall (HRpooled = 1.03, CI = 0.86-1.19) mortality (N = 3 studies). CONCLUSIONS: Increased physical activity was associated with improved quality of life, a reduced risk of colorectal cancer, and overall mortality rate. Given the paucity of the literature published on this topic, this finding should be interpreted with caution.

International trends in lung cancer incidence by histological subtype: adenocarcinoma stabilizing in men but still increasing in women.

OBJECTIVES: Trends in overall lung cancer incidence in different countries reflect the maturity of the smoking epidemic. Further understanding of the underlying causes for trends over time can be gained by assessing the trends by sex and histological subtype. We provide a temporal analysis of lung cancer incidence in 12 populations (11 countries), with a focus on cohort-specific trends for the main histological subtypes (squamous cell carcinomas (SCC), adenocarcinomas (AdC), and small cell carcinoma). MATERIAL AND METHODS: We restrict the analysis to population-based registry data of sufficient quality to provide meaningful interpretation, using data in Europe, North America and Oceania, extracted from successive Cancer Incidence in Five Continents Volumes. Poorly specified morphologies were reallocated to a specified grouping on a population, 5-year period and age group basis. RESULTS: In men, lung cancer rates have been declining overall and by subtype, since the beginning of the study period, except for AdC. AdC incidence rates have risen and surpassed those of SCC (historically the most frequent subtype) in the majority of these populations, but started to stabilize during the mid-1980s in North America, Australia and Iceland. In women, AdC has been historically the most frequent subtype and rates continue to increase in most populations studied. Early signs of a decline in AdC can however be observed in Canada, Denmark and Australia among very recent female cohorts, born after 1950. CONCLUSIONS: The continuing rise in lung cancer among women in many countries reinforces the need for targeted smoking cessation efforts alongside preventive actions.

Increased risk of chronic lymphocytic leukaemia among cancer survivors in the Netherlands: increased detection, causal factors or both?

We assessed the risk of chronic lymphocytic leukaemia (CLL) following earlier primary malignancies (EPM) to explore the extent and determinants of this risk. We used the Netherlands Cancer Registry data of 1,313,232 cancer survivors who were at risk to be subsequently diagnosed with CLL between 1989 and 2008. Cancer survivors were categorized based on gender, age, time since diagnosis of EPM and type of EPM. CLL was regarded synchronous when diagnosed within 3 months after diagnosis of EPM; metachronous CLLs were those diagnosed later. Overall, we found that cancer survivors had a 90 % higher risk to be diagnosed with CLL than the general population. In the first year after diagnosis, we found a more than four-fold increased risk of CLL (standardized incidence ratio (SIR), 4.4; 95 % confidence interval (CI), 4.1-4.8); however, no increased risk was observed after excluding synchronous cases. After 1 year, the excess risk of subsequent CLL ranged from 1.2 to 1.8. An increased risk for metachronous CLL was found in prostate (SIR 1.3; 95 % CI 1.1-1.5) and squamous cell skin cancer survivors (SIR 2.3; 95 % CI 1.9-2.7). Intensive clinical checkups after/around diagnosis of the EPM seemed to be the main cause for the increased risk of CLL among cancer survivors. However, possible shared risk factors between prostate cancer and CLL and skin cancer and CLL cannot be excluded. Further clinical research aimed at CLL as subsequent primary malignancy (SPM) is warranted to elucidate possible shared biological and predisposing risk factors.

Inferior survival for young patients with contralateral compared to unilateral breast cancer: a nationwide population-based study in the Netherlands.

To compare overall survival between women with unilateral breast cancer (UBC) and contralateral breast cancer (CBC). Women with UBC (N = 182,562; 95 %) and CBC (N = 8,912; 5 %) recorded in the Netherlands Cancer Registry between 1989 and 2008 were included and followed until 2010. We incorporated CBC as a time-dependent covariate to compute the overall mortality rate ratio between women with CBC and UBC. Prognostic factors for overall death were examined according to age at first breast cancer. Women with CBC exhibited a 30 % increase in overall mortality (Hazard Ratio (HR), 95 % Confidence Interval: 1.3, 1.3-1.4) compared with UBC, decreasing with rising age at diagnosis of first breast cancer (<50 years: 2.3, 2.2-2.5 vs. ≥70 years: 1.1, 1.0-1.1). Women older than 50 years at CBC diagnosis and diagnosed 2-5 years after their first breast cancer exhibited a 20 % higher death risk (1.2, 1.0-1.3) compared to those diagnosed within the first 2 years. In women younger than 50 years, the HR was significantly lower if the CBC was diagnosed >5 years after the first breast cancer (0.7, 0.5-0.9). The prognosis for women with CBC significantly improved over time (2004-2008: 0.6, 0.5-0.7 vs. 1989-1993). Women with CBC had a lower survival compared to women with UBC, especially those younger than 50 years at first breast cancer diagnosis. A tailored follow-up strategy beyond current recommendations is needed for these patients who, because of their age and absence of known familial risk, are currently not invited for population-based screening.

Risk of prostate cancer among cancer survivors in the Netherlands.

BACKGROUND: In parallel with increasing numbers of cancer patients and improving cancer survival, the occurrence of second primary cancers becomes a relevant issue. The aim of our study was to evaluate risk of prostate cancer as second primary cancer in a population-based setting. METHODS: Data from the Netherlands Cancer Registry were used to estimate standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for prostate cancer as second primary cancer. The effect of time since first cancer diagnosis, specific first cancer sites, age, and pelvic radiotherapy was taken into account. RESULTS: Out of 551,553 male patients diagnosed with a first primary cancer between 1989 and 2008, 9243 patients were subsequently diagnosed with prostate cancer. Overall, cancer survivors showed an increased risk (SIR 1.3, 95% CI 1.2-1.3) of prostate cancer. The increased prostate cancer risk was limited to the first year of follow-up for the majority of the specific first cancer sites. More than 10 years after the first cancer diagnosis, only melanoma patients were at increased risk (SIR 1.5, 95% CI 1.2-1.9), while patients with head or neck cancers were at decreased risk (SIR 0.7, 95% CI 0.5-0.9) of being diagnosed with prostate cancer. Patients who underwent primary pelvic radiotherapy for their first cancer had a decreased risk of prostate cancer in the long term (SIR 0.5, 95% CI 0.4-0.6). CONCLUSIONS: Our data showed that cancer survivors have an increased prostate cancer risk in the first year following a first cancer diagnosis, which is most likely the result of active screening or incidental detection.

Increased risks of third primary cancers of non-breast origin among women with bilateral breast cancer.

BACKGROUND: This study examined the risk of third cancer of non-breast origin (TNBC) among women with bilateral breast cancer (BBC; either synchronous or metachronous), focussing on the relation with breast cancer treatment. METHODS: Risk was assessed, among 8752 Dutch women diagnosed with BBC between 1989 and 2008, using standardised incidence ratios (SIR) and Cox regression analyses to estimate the hazard ratio (HR) of TNBC for different treatment modalities. RESULTS: Significant increased SIRs were observed for all TNBCs combined, haematological malignancies, stomach, colorectal, non-melanoma skin, lung, head and neck, endometrial, and ovarian cancer. A 10-fold increased risk was found for ovarian cancer among women younger than 50 years (SIR=10.0, 95% confidence interval (CI)=5.3-17.4). Radiotherapy was associated with increased risks of all TNBCs combined (HR=1.3; 95%CI=1.1-1.6, respectively). Endocrine therapy was associated with increased risks of all TNBCs combined (HR=1.2; 95%CI=1.0-1.5), haematological malignancies (HR=2.0; 95%CI=1.1-3.9), and head and neck cancer (HR=3.3; 95%CI=1.1-10.4). After chemotherapy decreased risks were found for all TNBCs combined (HR=0.63; 95%CI=0.5-0.87). CONCLUSION: Increased risk of TNBC could be influenced by genetic factors (ovarian cancer) or an effect of treatment (radiotherapy and endocrine therapy). More insight in the TNBC risk should further optimise and individualise treatment and surveillance protocols in (young) women with BBC.

Excess weight among colorectal cancer survivors: target for intervention.

BACKGROUND: Healthy lifestyle might improve outcome among colorectal cancer (CRC) survivors. In this study we investigated the proportion of survivors who meet recommended lifestyle and weight guidelines and compared this to the general population. Factors that predict current behaviour were also assessed. METHOD: A random sample of CRC survivors diagnosed between 1998 and 2007 were surveyed. Percentages of current smokers, alcohol consumers, excess weight and clustering of these variables were calculated. Using logistic regression we assessed demographical and clinical factors that predict current lifestyle and excess weight. RESULTS: We included 1349 (74% response rate) survivors in this study of whom only 8 and 16% of male and female survivors met the recommended lifestyle and body weight. Among male survivors up to 10% had at least two unhealthy lifestyle factors and among women, up to 19%. The proportion of smokers and those who had ever consumed alcohol was lower compared to the general population (13 vs. 31%, 82 vs. 86% respectively), but excess weight (BMI at least 25 kg/m(2)) was more prevalent among survivors (69 vs. 53% respectively). Having received chemotherapy was significantly associated with being overweight (adjusted odd ratio 1.5, 95% confidence interval 1.05-2.3). Younger patients, male gender and survivors of lower socioeconomic status were more likely to show non-compliance to healthy lifestyle recommendations. CONCLUSION: The observed clustering of unhealthy lifestyle warrants interventions targeting multiple behaviours simultaneously. Reducing excess weight should be one of the most important targets of interventions, particularly for males, those who had chemotherapy and survivors of lower socioeconomic status.

Lifestyle changes and reduction of colon cancer incidence in Europe: A scenario study of physical activity promotion and weight reduction.

BACKGROUND: Across Europe, there are over 300,000 new cases of colorectal cancer annually. Major risk factors include excess body weight (usually expressed by a high body mass index, BMI) and physical inactivity (PA). In this study we modelled the potential long-term effects on colon cancer incidence of changes in prevalence of excess body weight and physical inactivity in seven European countries across Europe with adequate data. METHODS: We addressed the impact of interventions aimed at preventing weight gain and increasing physical activity on colon cancer incidence using the Prevent model as refined in the FP-6 Eurocadet project. Relative risk (RR) estimates were derived from meta-analyses; sex- and country-specific prevalences of BMI and PA were determined from survey data. Models were made for Czech Republic, Denmark, France, Latvia, the Netherlands, Spain and the United Kingdom. RESULTS: In a hypothetical scenario in which a whole population had obtained an ideal weight distribution in the year 2009, up to 11 new cases per 100,000 person-years would be avoided by 2040. The population attributable fractions (PAF) for excess weight were much higher for males (between 13.5% and 18.2%) than for females (2.3-4.6%). In contrast, using the optimum scenario where everybody in Europe would adhere to the recommended guideline of at least 30 min of moderate PA 5d per week, the PAFs for PA in various countries were substantially greater in women (4.4-21.2%) than in men (3.2-11.6%). Sensitivity analyses were performed assuming underreporting of BMI by using self-reports (difference of 5 and 0.8 percent-points in males and females, respectively), using different risk estimates (between 5.8 and 11.5 percent-points difference for BMI for men and women, respectively, and up to 11.6 percent-points difference for PA for women). INTERPRETATION: Changes in lifestyle can indeed result in large health benefits, including for colon cancer. Two interesting patterns emerged: for colon cancer, achieving optimum BMI levels in the population appears to offer the greatest health benefits in population attributable fractions in males, while increased physical activity might offer the greatest fraction of avoidable cancers in females. These observations suggest a sex-specific strategy to colon cancer prevention.

Incidence of cancer in first-degree relatives of basal cell carcinoma patients.

There is evidence to suggest that genetic factors play an important role in the development of basal cell carcinomas (BCCs), and that skin neoplasms might be a sign for a genetic predisposition to cancer. We investigated whether the incidence of visceral and skin malignancies among first-degree relatives of BCC-patients was increased. Postal questionnaires were sent to 249 BCC-patients, who were divided into two groups (young = BCC under the age of 51 years and older = BCC over the age of 50 years), and asked them about cancer in their first-degree relatives. The reported numbers of cancer among the relatives were compared with the expected numbers based on sex and age-specific population-based incidence rates. The accuracy of the reported diagnoses was verified. A total of 157 BCC-patients reported 277 malignancies in 1,272 relatives. The incidence of the following cancers was higher than expected in relatives from young BCC-patients: bone and soft tissue (O/E = 3.91; 95% CI: 1.43-8.66), skin (O/E = 2.13; 95% CI: 1.30-3.29) and digestive tract (O/E = 1.59; 95% CI: 1.10-2.23). In relatives of older BCC-patients, only the incidence of digestive tract cancer was higher than expected (O/E = 1.44; 95% CI: 1.08-1.89). Diagnoses that were verified turned out to be accurate in 87% of the cases. This study suggests that the risk of certain cancers, particularly that of the digestive tract, in first-degree relatives of BCC-patients is increased. These findings may indicate a genetic predisposition to both skin and visceral malignancies in this patient group.

Rising incidence of breast cancer among female cancer survivors: implications for surveillance.

The number of female cancer survivors has been rising rapidly. We assessed the occurrence of breast cancer in these survivors over time. We computed incidence of primary breast cancer in two cohorts of female cancer survivors with a first diagnosis of cancer at ages 30+ in the periods 1975-1979 and 1990-1994. Cohorts were followed for 10 years through a population-based cancer registry. Over a period of 15 years, the incidence rate of breast cancer among female cancer survivors increased by 30% (age-standardised rate ratio (RR-adj): 1.30; 95% CI: 1.03-1.68). The increase was significant for non-breast cancer survivors (RR-adj: 1.41, 95% CI: 1.04-2.75). During the study period, the rate of second breast cancer stage II tripled (RR-adj: 3.10, 95% CI: 1.73-5.78). Non-breast cancer survivors had a significantly (P value=0.005) more unfavourable stage distribution (62% stage II and III) than breast cancer survivors (32% stage II and III). A marked rise in breast cancer incidence among female cancer survivors was observed. Research to optimise follow-up strategies for these women to detect breast cancer at an early stage is warranted.

Are patients with skin cancer at lower risk of developing colorectal or breast cancer?

Ultraviolet exposure may reduce the risk of colorectal and breast cancer as the result of rising vitamin D levels. Because skin cancer is positively related to sun exposure, the authors hypothesized a lower incidence of breast and colorectal cancer after skin cancer diagnosis. They analyzed the incidence of colorectal and breast cancer diagnosed from 1972 to 2002 among 26,916 Netherlands skin cancer patients (4,089 squamous cell carcinoma (SCC), 19,319 basal cell carcinoma (BCC), and 3,508 cutaneous malignant melanoma (CMM)). Standardized incidence ratios were calculated. A markedly decreased risk of colorectal cancer was found for subgroups supposedly associated with the highest accumulated sun exposure: men (standardized incidence ratio (SIR) = 0.83, 95% confidence interval (CI): 0.71, 0.97); patients with SCC (SIR = 0.64, 95% CI: 0.43, 0.93); older patients at SCC diagnosis (SIR = 0.59, 95% CI: 0.37, 0.88); and patients with a SCC or BCC lesion on the head and neck area (SIR = 0.59, 95% CI: 0.36, 0.92 for SCC and SIR = 0.78, 95% CI: 0.63, 0.97 for BCC). Patients with CMM exhibited an increased risk of breast cancer, especially advanced breast cancer (SIR = 2.20, 95% CI: 1.10, 3.94) and older patients at CMM diagnosis (SIR = 1.87, 95% CI: 1.14, 2.89). Study results suggest a beneficial effect of continuous sun exposure against colorectal cancer. The higher risk of breast cancer among CMM patients may be related to socioeconomic class, both being more common in the affluent group.