Trends in the incidence of colorectal cancer in sub-Saharan Africa: A population-based registry study.

In sub-Saharan Africa, colorectal cancer (CRC) has historically been considered a rare disease, although some previous studies have suggested that the incidence is increasing. We examine time trends in the incidence of CRC using data from 12 population-based cancer registries in 11 countries of sub-Saharan Africa that were able to provide time series data for periods of 12 or more years, or with earlier data with which recent rates may be compared. Age-standardized incidence rates were highest in the higher-income countries, and were increasing in all of the populations studied, and these increases were statistically significant in all but three. Current evidence has suggested a link between the increased adoption of western lifestyle habits with colorectal cancer, and along with increasing urbanization of African populations, there is an increase in body weight, as well as evidence of increasing consumption of meat, sugars, and alcohol.

Treatment and Survival Among Patients With Colorectal Cancer in Sub-Saharan Africa: A Multicentric Population-Based Follow-Up Study.

BACKGROUND: The burden of colorectal cancer (CRC) is increasing in Sub-Saharan Africa (SSA). However, little is known about CRC treatment and survival in the region. METHODS: A random sample of 653 patients with CRC diagnosed from 2011 to 2015 was obtained from 11 population-based cancer registries in SSA. Information on clinical characteristics, treatment, and/or vital status was obtained from medical records in treating hospitals for 356 (54%) of the patients ("traced cohort"). Concordance of CRC treatment with NCCN Harmonized Guidelines for SSA was assessed. A Cox proportional hazards model was used to examine the association between survival and human development index (HDI). RESULTS: Of the 356 traced patients with CRC, 51.7% were male, 52.8% were from countries with a low HDI, 55.1% had colon cancer, and 73.6% were diagnosed with nonmetastatic (M0) disease. Among the patients with M0 disease, however, only 3.1% received guideline-concordant treatment, 20.6% received treatment with minor deviations, 31.7% received treatment with major deviations, and 35.1% received no treatment. The risk of death in patients who received no cancer-directed therapy was 3.49 (95% CI, 1.83-6.66) times higher than in patients who received standard treatment or treatment with minor deviations. Similarly, the risk of death in patients from countries with a low HDI was 1.67 (95% CI, 1.07-2.62) times higher than in those from countries with a medium HDI. Overall survival at 1 and 3 years was 70.9% (95% CI, 65.5%-76.3%) and 45.3% (95% CI, 38.9%-51.7%), respectively. CONCLUSIONS: Fewer than 1 in 20 patients diagnosed with potentially curable CRC received standard of care in SSA, reinforcing the need to improve healthcare infrastructure, including the oncology and surgical workforce.

Prostate cancer survival in sub-Saharan Africa by age, stage at diagnosis, and human development index: a population-based registry study.

OBJECTIVES: To estimate observed and relative survival of prostate cancer patients in sub-Saharan Africa (SSA) and to examine the influence of age, stage at diagnosis and the Human Development Index (HDI). PATIENTS AND METHODS: In this comparative registry study, we selected a random sample of 1752 incident cases of malign prostatic neoplasm from 12 population-based cancer registries from 10 SSA countries, registered between 2005 and 2015. We analyzed the data using Kaplan-Meier and Ederer II methods to obtain outcome estimates and flexible Poisson regression modeling to calculate the excess hazards of death RESULTS: For the 1406 patients included in the survival analyses, 763 deaths occurred during 3614 person-years of observation. Of patients with known stage, 45.2% had stage IV disease, 31.2% stage III and only 23.6% stage I and II. The 1 and 5-year relative survival for the entire cohort was 78.0% (75.4-80.7) and 60.0% (55.7-64.6), while varying between the registries. Late presentation was associated with increased excess hazards and a 0.1 increase in the HDI was associated with a 20% lower excess hazard of death, while for age at diagnosis no association was found. CONCLUSIONS: We found poor survival of SSA prostatic tumor patients, as well as high proportions of late stage presentation, which are associated with inferior outcome. This calls for investment in health-care systems and action regarding projects to raise awareness among the population to achieve earlier diagnosis and improve survival.

Colorectal cancer survival in sub-Saharan Africa by age, stage at diagnosis and Human Development Index: A population-based registry study.

There are limited population-based survival data for colorectal cancer (CRC) in sub-Saharan Africa. Here, 1707 persons diagnosed with CRC from 2005 to 2015 were randomly selected from 13 population-based cancer registries operating in 11 countries in sub-Saharan Africa. Vital status was ascertained from medical charts or through next of kin. 1-, 3- and 5-year overall and relative survival rates for all registries and for each registry were calculated using the Kaplan-Meier estimator. Multivariable analysis was used to examine the associations of 5-year relative survival with age at diagnosis, stage and country-level Human Development Index (HDI). Observed survival for 1448 patients with CRC across all registries combined was 72.0% (95% CI 69.5-74.4%) at 1 year, 50.4% (95% CI 47.6-53.2%) at 3 years and 43.5% (95% CI 40.6-46.3%) at 5 years. We estimate that relative survival at 5 years in these registry populations is 48.2%. Factors associated with poorer survival included living in a country with lower HDI, late stage at diagnosis and younger or older age at diagnosis (<50 or ≥70 years). For example, the risk of death was 1.6 (95% CI 1.2-2.1) times higher for patients residing in medium-HDI and 2.7 (95% CI 2.2-3.4) times higher for patients residing in low-HDI compared to those residing in high-HDI countries. Survival for CRC remains low in sub-Saharan African countries, though estimates vary considerably by HDI. Strengthening health systems to ensure access to prevention, early diagnosis and appropriate treatment is critical in improving outcomes of CRC in the region.

Cancer statistics for the year 2020: An overview.

Our study briefly reviews the data sources and methods used in compiling the International Agency for Research on Cancer (IARC) GLOBOCAN cancer statistics for the year 2020 and summarises the main results. National estimates were calculated based on the best available data on cancer incidence from population-based cancer registries (PBCR) and mortality from the World Health Organization mortality database. Cancer incidence and mortality rates for 2020 by sex and age groups were estimated for 38 cancer sites and 185 countries or territories worldwide. There were an estimated 19.3 million (95% uncertainty interval [UI]: 19.0-19.6 million) new cases of cancer (18.1 million excluding non-melanoma skin cancer) and almost 10.0 million (95% UI: 9.7-10.2 million) deaths from cancer (9.9 million excluding non-melanoma skin cancer) worldwide in 2020. The most commonly diagnosed cancers worldwide were female breast cancer (2.26 million cases), lung (2.21) and prostate cancers (1.41); the most common causes of cancer death were lung (1.79 million deaths), liver (830000) and stomach cancers (769000).

Cervical Cancer in Sub-Saharan Africa: A Multinational Population-Based Cohort Study of Care and Guideline Adherence.

BACKGROUND: Cervical cancer (CC) is the most common female cancer in many countries of sub-Saharan Africa (SSA). We assessed treatment guideline adherence and its association with overall survival (OS). METHODS: Our observational study covered nine population-based cancer registries in eight countries: Benin, Ethiopia, Ivory Coast, Kenya, Mali, Mozambique, Uganda, and Zimbabwe. Random samples of 44-125 patients diagnosed from 2010 to 2016 were selected in each. Cancer-directed therapy (CDT) was evaluated for degree of adherence to National Comprehensive Cancer Network (U.S.) Guidelines. RESULTS: Of 632 patients, 15.8% received CDT with curative potential: 5.2% guideline-adherent, 2.4% with minor deviations, and 8.2% with major deviations. CDT was not documented or was without curative potential in 22%; 15.7% were diagnosed with International Federation of Gynecology and Obstetrics (FIGO) stage IV disease. Adherence was not assessed in 46.9% (no stage or follow-up documented, 11.9%, or records not traced, 35.1%). The largest share of guideline-adherent CDT was observed in Nairobi (49%) and the smallest in Maputo (4%). In patients with FIGO stage I-III disease (n = 190), minor and major guideline deviations were associated with impaired OS (hazard rate ratio [HRR], 1.73; 95% confidence interval [CI], 0.36-8.37; HRR, 1.97; CI, 0.59-6.56, respectively). CDT without curative potential (HRR, 3.88; CI, 1.19-12.71) and no CDT (HRR, 9.43; CI, 3.03-29.33) showed substantially worse survival. CONCLUSION: We found that only one in six patients with cervical cancer in SSA received CDT with curative potential. At least one-fifth and possibly up to two-thirds of women never accessed CDT, despite curable disease, resulting in impaired OS. Investments into more radiotherapy, chemotherapy, and surgical training could change the fatal outcomes of many patients. IMPLICATIONS FOR PRACTICE: Despite evidence-based interventions including guideline-adherent treatment for cervical cancer (CC), there is huge disparity in survival across the globe. This comprehensive multinational population-based registry study aimed to assess the status quo of presentation, treatment guideline adherence, and survival in eight countries. Patients across sub-Saharan Africa present in late stages, and treatment guideline adherence is remarkably low. Both factors were associated with unfavorable survival. This report warns about the inability of most women with cervical cancer in sub-Saharan Africa to access timely and high-quality diagnostic and treatment services, serving as guidance to institutions and policy makers. With regard to clinical practice, there might be cancer-directed treatment options that, although not fully guideline adherent, have relevant survival benefit. Others should perhaps not be chosen even under resource-constrained circumstances.

Rising Prostate Cancer Incidence in Sub-Saharan Africa: A Trend Analysis of Data from the African Cancer Registry Network.

BACKGROUND: Prostate cancer is the leading cancer in men in sub-Saharan Africa (SSA) regarding incidence and mortality. Published data from a few registries in SSA suggest that the rates are still rising, but there is little comprehensive information on the time trends of prostate cancer incidence. METHODS: We analyzed registry data on 13,170 incident prostate cancer cases in men aged 40 years or above, from 12 population-based cancer registries in 11 SSA countries, with at least a 10-year time span of comparable data. RESULTS: We observed an increase in cumulative risks (CR) and age-standardized incidence rates (ASR) over time in all registries (statistically significant in all but one). The highest values of CR were found in Seychelles and Harare (Zimbabwe). The highest annual increase in the ASRs was seen in Seychelles and Eastern Cape (South Africa), whereas the lowest was seen in Mauritius. We mainly found a steady increase in incidence with age and during successive periods. CONCLUSIONS: This analysis reveals that prostate cancer incidence rates are rising in many populations in SSA-often very rapidly-which is in contrast to recent observations worldwide. We acknowledge that the reasons are multifactorial and largely remain unclear, but believe that they are primarily associated with improvements in health care systems, for example, a broader use of prostate-specific antigen testing. IMPACT: This study is the first to compare population-level data on time trends of prostate cancer incidence between multiple countries of SSA, presenting the different rates of increase in 11 of them.

Clinical presentation and diagnosis of adult patients with non-Hodgkin lymphoma in Sub-Saharan Africa.

Non-Hodgkin lymphoma (NHL) is the sixth most common cancer in Sub-Saharan Africa (SSA). Comprehensive diagnostics of NHL are essential for effective treatment. Our objective was to assess the frequency of NHL subtypes, disease stage and further diagnostic aspects. Eleven population-based cancer registries in 10 countries participated in our observational study. A random sample of 516 patients was included. Histological confirmation of NHL was available for 76.2% and cytological confirmation for another 17.3%. NHL subclassification was determined in 42.1%. Of these, diffuse large B cell lymphoma, chronic lymphocytic leukaemia and Burkitt lymphoma were the most common subtypes identified (48.8%, 18.4% and 6.0%, respectively). We traced 293 patients, for whom recorded data were amended using clinical records. For these, information on stage, human immunodeficiency virus (HIV) status and Eastern Cooperative Oncology Group Performance Status (ECOG PS) was available for 60.8%, 52.6% and 45.1%, respectively. Stage at diagnosis was advanced for 130 of 178 (73.0%) patients, HIV status was positive for 97 of 154 (63.0%) and ECOG PS was ≥2 for 81 of 132 (61.4%). Knowledge about NHL subclassification and baseline clinical characteristics is crucial for guideline-recommended treatment. Hence, regionally adapted investments in pathological capacity, as well as standardised clinical diagnostics, will significantly improve the therapeutic precision for NHL in SSA.

Cancer in Mozambique: Results from two population-based cancer registries.

Results from two recently established population-based registries in Mozambique are reported: Beira in the central region (2014-2017) and Maputo, the capital city, in the South (2015-2017). The results are compared to those from Maputo (Lourenço Marques at the time) in 1956-1960 (appearing Cancer Incidence in Five Continents Vol 1), and with estimated incidence rates from other regions of Africa. The elevated prevalence of HIV infection (12.6% of adults in 2018) results in high rates for HIV-related cancers, and the greater prevalence in central Mozambique, compared to the south, largely explains the rather higher rates of Kaposi sarcoma (males), non-Hodgkin lymphoma, squamous cell carcinoma of conjunctiva and cervical cancer in Beira than in Maputo. Burkitt lymphoma is the commonest childhood cancer in Beira, with high rates typical of East Africa, while the low rates in Maputo are more typical of Southern Africa. Overall, 44% of cancers in Maputo and 52% in Beira are estimated to be caused by infectious agents. In the last 60 years, cancers more frequent in developed countries, such as breast and prostate, are emerging in Mozambique. The incidence of the former in Maputo has increased fivefold since 1956-1960, that of prostate cancer 2.5-fold, and that of large bowel cancer doubled. The results reported here were used to make national estimates of incidence, mortality and prevalence in Globocan 2018. The two registries were important in providing data to establish priority actions in the National Cancer Control Plan, and are a valuable resource to monitor progress toward its goals.

Cancer in Africa 2018: The role of infections.

We estimate the fractions of cancer attributed to infections in Africa in 2018. The number of new cancer cases occurring was taken from Globocan2018 with some additional estimations based on data from African population-based registries. Population attributable fractions were calculated using prevalence of infection and relative risk in exposed vs. nonexposed. The greatest share of infection-associated cancers is due to the human papillomaviruses (12.1% of all cancers in Africa and 15.4% in sub-Saharan Africa [SSA]); of these, cervical cancer is by far the most common. Kaposi sarcoma-associated herpesvirus is responsible for 3.1% of all cancers in Africa, the hepatitis viruses (B and C) for 2.9% and Helicobacter pylori for 2.7% (non-Cardia Gastric cancer and primary gastric lymphomas). Two percent of cancers are attributable to the Epstein-Barr virus, Schistosoma haematobium increases the risk of bladder cancer resulting in 1.0% of all cancers. HIV-related NHL and squamous cell carcinoma of the conjunctiva account for 0.6% of cancers. Altogether 24.5% of cancers in Africa and 28.7% in SSA are due to infectious agents. Infections are by far the most common cancer risk factor for cancer in Africa-the traditional risk factors (smoking, alcohol and unhealthy diet) probably cause only one in eight cancers in Africa. Prevention should focus on those infectious diseases preventable through vaccination (HPV and hepatitis B) which could reduce two-thirds of the burden. Helicobacter pylori and schistosomiasis are treatable with antibiotics and praziquantel, with a potential reduction of one in eight infection-associated cancers.

Breast cancer survival in sub-Saharan Africa by age, stage at diagnosis and human development index: A population-based registry study.

Breast cancer is the leading cancer diagnosis and second most common cause of cancer deaths in sub-Saharan Africa (SSA). Yet, there are few population-level survival data from Africa and none on the survival differences by stage at diagnosis. Here, we estimate breast cancer survival within SSA by area, stage and country-level human development index (HDI). We obtained data on a random sample of 2,588 breast cancer incident cases, diagnosed in 2008-2015 from 14 population-based cancer registries in 12 countries (Benin, Cote d'Ivoire, Ethiopia, Kenya, Mali, Mauritius, Mozambique, Namibia, Seychelles, South Africa, Uganda and Zimbabwe) through the African Cancer Registry Network. Of these, 2,311 were included for survival analyses. The 1-, 3- and 5-year observed and relative survival (RS) were estimated by registry, stage and country-level HDI. We equally estimated the excess hazards adjusting for potential confounders. Among patients with known stage, 64.9% were diagnosed in late stages, with 18.4% being metastatic at diagnosis. The RS varied by registry, ranging from 21.6%(8.2-39.8) at Year 3 in Bulawayo to 84.5% (70.6-93.5) in Namibia. Patients diagnosed at early stages had a 3-year RS of 78% (71.6-83.3) in contrast to 40.3% (34.9-45.7) at advanced stages (III and IV). The overall RS at Year 1 was 86.1% (84.4-87.6), 65.8% (63.5-68.1) at Year 3 and 59.0% (56.3-61.6) at Year 5. Age at diagnosis was not independently associated with increased mortality risk after adjusting for the effect of stage and country-level HDI. In conclusion, downstaging breast cancer at diagnosis and improving access to quality care could be pivotal in improving breast cancer survival outcomes in Africa.

Five year cancer incidence in Calabar, Nigeria (2009-2013).

Cancer incidence rates are presented for the Calabar Cancer Registry, a population-based cancer registry (PBCR) covering the population of two Local Government Areas (LGAs) of Calabar the capital of Cross-River State, Nigeria. (375,196 inhabitants in 2006). During the period 2009-2013, a total of 719 new cases were registered comprising 320 men (an age standardised incidence rate (ASR) of 78.8 per 100,000) and 399 women (ASR of 86.9 per 100,000). Breast and cervical cancers account for 60.4% of all cancers in women, with breast cancer (ASR 35 per 100,000) almost twice as common as cervix cancer (ASR 21 per 100,000) and occurring in rather younger women. Prostate cancer was the most common cancer in men (ASR 50.8 per 100,000). Hodgkin's lymphoma was common in both sexes, and there were moderate numbers of HIV-related cancers recorded (Kaposi sarcoma, non Hodgkin lymphoma, and squamous cell carcinomas of conjunctiva).

Factors Affecting Health-Related Quality of Life in Patients With Cholangiocarcinoma in the Northeastern Region of Thailand.

BACKGROUND: Cholangiocarcinoma (CCA) remains a major health problem and causes high mortality in Northeastern Thailand. Patients with CCA have a poor prognosis, and little is known about their health-related quality of life (HRQOL) and its determinants. OBJECTIVE: The objective of this study was to investigate factors affecting HRQOL and its changes over time among CCA patients. METHODS: Two hundred thirty-seven patients with CCA were recruited during a 6-month period in 2011 in 5 tertiary hospitals in 4 provinces of northeastern Thailand. Health-related quality of life after diagnosis of CCA was measured by the Functional Assessment of Cancer Therapy-Hepatobiliary questionnaire (Thai version 4). The HRQOL score of CCA patients at different times after diagnosis was compared by repeated-measures analysis of variance. Generalized estimating equation was used to identify factors affecting HRQOL among CCA patients. RESULTS: Of 237 eligible patients registered, 99 confirmed cases completed follow-up at 2 months. Overall HRQOL varied over time, with the score at baseline being significantly lower than 1 and 2 months later. An adjusted analysis showed that patients who were 60 to 69 years old had higher HRQOL scores than did younger patients. Patients using alternative medicine had lower HRQOL scores than did those who did not. CONCLUSIONS: Health-related quality-of-life scores among CCA patients changed over time and were related to age at recruitment and use of alternative medicine. IMPLICATIONS FOR PRACTICE: Healthcare providers should carefully communicate about the diagnosis and its implications. Patients with CCA, especially younger patients and those who have used traditional medicine, may benefit from counseling and help with mobilizing family and social support.

Building capacity for sustainable research programmes for cancer in Africa.

Cancer research in Africa will have a pivotal role in cancer control planning in this continent. However, environments (such as those in academic or clinical settings) with limited research infrastructure (laboratories, biorespositories, databases) coupled with inadequate funding and other resources have hampered African scientists from carrying out rigorous research. In September 2012, over 100 scientists with expertise in cancer research in Africa met in London to discuss the challenges in performing high-quality research, and to formulate the next steps for building sustainable, comprehensive and multi-disciplinary programmes relevant to Africa. This was the first meeting among five major organizations: the African Organisation for Research and Training in Africa (AORTIC), the Africa Oxford Cancer Foundation (AfrOx), and the National Cancer Institutes (NCI) of Brazil, France and the USA. This article summarizes the discussions and recommendations of this meeting, including the next steps required to create sustainable and impactful research programmes that will enable evidenced-based cancer control approaches and planning at the local, regional and national levels.

Pediatric, elderly, and emerging adult-onset peaks in Burkitt's lymphoma incidence diagnosed in four continents, excluding Africa.

Burkitt's lymphoma (BL) in the general population and immunosuppressed persons with AIDS in the United States was characterized by three age-specific incidence peaks near 10, 40, and 70 years. We hypothesized that BL from different geographical areas may exhibit pediatric, adult, and elderly age incidence peaks. We investigated this hypothesis using data on 3,403 cases obtained from the International Agency for Research on Cancer (1963-2002). Data from Africa were sparse or incomplete, and thus were excluded. Age-standardized rates (ASRs) and age-specific incidence rates were calculated, supplemented with the calculations performed using age-period-cohort (APC) models. The ASR rose 5.3% (95% confidence interval [CI], 5.0-5.6) per year in males and 4.6% (95% CI, 4.5-4.8) in females. The ASR increased gradually in children, steeply in adults and most rapidly in the elderly both in males and in females. Overall, BL male/female ASR ratio was 2.5, but it declined from 3.1 (95% CI, 3.0-3.3) for pediatric BL to 2.3 (95% CI, 2.2-2.4) for adult BL and 1.5 (95% CI, 1.4-1.6) for elderly BL. Age-specific incidence peaks occurred near 10 and 70 years in all regions and periods. A peak near 40 years of age emerged in the mid-1990s, particularly in men. Findings using APC models confirmed those based on the standard analyses. Our findings, based on the international BL cases, support our hypothesis that BL is multimodal and that BL peaks at different ages may be clues to differences in the etiology and/or biology of BL at those ages.

Trends in the incidence of cancer in the Sousse region, Tunisia, 1993-2006.

In this article, we analyzed trends in incidence rates of the major cancer sites for a 14-year period, 1993-2006, in the Sousse region localized in the centre of Tunisia. Five-year age-specific rates, crude incidence rates (CR), world age-standardized rates (ASR), percent change (PC) and annual percent change (APC) were calculated using annual data on population size and its estimated age structure. A total of 6,975 incident cases of cancer were registered, with a male to-female sex ratio of 1.4:1. ASRs showed stable trends (-0.1% in males, and +1.0% in females). The leading cancer sites in rank were lung, breast, lymphoma, colon-rectum, bladder, prostate, leukemia, stomach and cervix uteri. For males, the incidence rates of lung, bladder and prostate cancers remained stable over time. While, cancers of colon-rectum showed a marked increase in incidence (APC: +4.8%; 95% CI: 1.2%, 8.4%) and non-Hodgkin's lymphoma (NHL) showed a notable decline (APC: -4.4%; 95% CI: -8.2, -0.6). For females, cancers of the breast (APC: +2.2%; 95% CI: 0.4%, 4.0%) and corpus uteri (APC: +7.4%; 95% CI: 2.8%, 12.0%) showed a marked increase in incidence during the study period, while the cervix uteri cancer decreased significantly (APC: -6.1%; 95% CI: -9.2%, -3.0%). The results underline the increasing importance of cancer as a cause of mortality and morbidity in Tunisia. Our findings justify the need to develop effective program aiming at the control and prevention of the spread of cancer amongst Tunisian population.

Cancer incidence in a rural population of South Africa, 1998-2002.

Cancer incidence rates and patterns are reported for a rural population, living in the Eastern Cape Province of South Africa for the period 1998-2002. The population-based cancer registry has operated for 20 years, using both active and passive methods for case finding, through collaborations with 19 health facilities: 11 district hospitals, 7 referral hospitals and 1 regional laboratory. The age standardized incidence rates for all cancers were 73.1 per 100,000 in males and 64.1 per 100,000 in females. The leading top 5 cancers for males were oesophagus (32.7 per 100,000), lung (5.8 per 100,000), prostate (4.4 per 100,000), liver (4.4 per 100,000) and larynx (2.5 per 100,000) whereas for females they were cervix (21.7 per 100,000), oesophagus (20.2 per 100,000), breast (7.5 per 100,000), ovary (0.9 per 100,000) and liver (0.9 per 100,000). The incidence of Kaposi sarcoma was low, and higher for males (1.6 per 100,000) than females (0.3 per 100,000). Lung cancer in both males and females was relatively low compared to the high incidence of oesophagus cancer.

The evolution of the population-based cancer registry.

The idea of recording information on all cancer cases in defined communities dates from the first half of the twentieth century, and there has been a steady growth in the number of such cancer registries since. Originally, they were concerned primarily with describing cancer patterns and trends. Later, many were able to follow up the registered patients and calculate survival. In the last 20 years the role of registries has expanded further to embrace the planning and evaluation of cancer control activities, and the care of individual cancer patients. This Review looks at the current status of cancer registration practice and use from an international perspective, mindful that the registration of cancer has expanded into a global activity.

Population-based incidence estimates of uveal melanoma in Germany. Supplementing cancer registry data by case-control data.

Valid incidence rates of uveal melanoma (UM) from German population-based cancer registries are currently not available due to under-reporting. We conducted two case-control studies on UM at a reference centre for eye tumours and show the influence on population-based incidences of UM when data from case-control studies are linked with a cancer registry. The first case-control study (1996-1998) recruited 13 UM cases aged 35-74 years and the second case-control study (2002-2003) recruited 20 UM cases aged 20-74 residing within the population covered by the Münster Cancer Registry. After record linkage, age-truncated and standardized (World Standard Population) incidences with and without the record linkage were compared. Incidence rates based on routine cancer registration increased by a factor of 1.7 (1996-1998, age group 35-74 years) and 3.7 (2002-2003, age group 20-74 years) after record linkage with the case-control data. The supplemented age-standardized incidence of UM is 8.6 per million (20-74 years, 2002-2003) compared with the unsupplemented incidence of 2.3 per million. UM unknown to the registry were less often morphologically verified than those known to the registry. Cancer registries relying on pathology reports underestimate UM incidences if eye-preserving treatments are introduced. Close co-operation between cancer referral centres and cancer registries can substantially improve the completeness of registration.