(1) Background: Haematological malignancies (HMs) represent a heterogeneous group of mostly rare cancers that differ in pathophysiology, incidence, and outcome. (2) Methods: Our study aims to understand the epidemiological situation and trends of 24 main types of HMs in Belgium over a 15-year period, with a focus on the impact of age. Age-standardised incidence, average annual percentage change (AAPC), 5- and 10-year relative survival (RS) and RS trends were estimated for all HMs (N = 94,415) diagnosed between 2004 and 2018. (3) Results: Incidence rates of HM increased, mainly in the 70+ age group (AAPC: 3%). RS varied by age and HM type. For each HM type, outcome decreased with age. The greatest decrease with age in 5-year RS is observed for aggressive HM, acute myeloid leukaemia (AML), acute lymphoblastic leukaemia, and Burkitt lymphoma, from 67%, 90%, and 97% below 20 years, to 2%, 12%, and 16% above 80 years of age, respectively. The moderate improvement in 5-year RS over the 2004–2018 period for all HMs, of +5 percentage point (pp), masks highly heterogenous outcomes by HM type and age group. The most impressive improvements are observed in the 80+ group: +45, +33, +28, and +16 pp for Hodgkin lymphoma, immunoproliferative disorders, follicular lymphoma, and chronic myeloid leukaemia, respectively. (4) Conclusions: The increasing incidence and survival over the 2004–2018 period are likely explained by diagnostic and therapeutic innovations, which have spread to populations not targeted by clinical trials, especially older adults. This real-world population-based study highlights entities that need significant improvement, such as AML.

Background/Objectives: This population-based study examined epidemiological trends of primary cancers in adolescents and young adults (AYAs) to enhance the understanding of the specific spectrum of cancers impacting AYAs in Belgium. Methods: Data on incidence, prevalence, mortality, and survival were obtained from the Belgian Cancer Registry (2004–2020, N = 43,535). (A)APC statistics were compared with children (5–14 years) and adults (40–49 years). Results: Cancer incidence increased by 0.4% annually from 66 to 80 per 100,000 person-years (ESR2013) but stabilised after 2015, except for Hodgkin lymphoma, chronic myeloid neoplasms, and testicular and breast cancer, which continued to rise. Mortality decreased by 1% annually, from 10 to 7 per 100,000 person-years (2004–2019). Five-year relative survival (RS) was 87% but remained low for certain cancers, including ovary (78%), central nervous system (67%), precursor haematopoietic neoplasms (64%), gastrointestinal (excl. colorectal) (49%), and lung-bronchus-trachea cancers (42%). Conclusions: From 2004–2020, the cancer burden among AYAs in Belgium increased due to improved survival, while incidence stabilised after 2015. Five-year RS exceeds 80% overall but remains lower for some cancers compared to children (e.g., precursor haematopoietic neoplasms) or older adults (e.g., breast cancer, sarcoma). The Belgian epidemiological trends align with those in neighbouring countries (Netherlands, France, Germany).

Colorectal cancer (CRC) incidence is rising among young adults globally, yet European data remain inconclusive. This study evaluated age- and sex-specific trends in CRC incidence, adenoma detection, and mortality in Belgium, with a focus on individuals aged 20-49 years. Diagnostic procedure trends in the 40-49 years age group were also analyzed to contextualize epidemiological patterns. Data from the Belgian Cancer Registry and diagnostic records from health insurance organizations were used to analyze trends in invasive CRC, in situ CRC, and adenomas and related diagnostic procedures. Mortality data were also included. Age-specific incidence rates and annual percentage changes were calculated using joinpoint regression analysis. Invasive CRC incidence remained stable in individuals aged 40-49 years between 2004 and 2023, whereas adenoma and in situ CRC rates increased, coinciding with increased use of fecal immunochemical tests and colonoscopy. Mortality in this age group was stable or declined. Conversely, individuals aged 30-39 years showed increasing trends in adenomas, in situ tumors, and both early- and advanced-stage CRC. Stages I-IV CRC incidence rose significantly in the 30-34 and 35-39 years age groups, with stage IV increasing by 9% and 5% annually, respectively. Adenoma incidence increased in nearly all age groups <50 years, except for males aged 20-24 years and individuals aged 25-29 years. Diagnostic activity, particularly between 2010 and 2014, likely contributed to early lesion detection. Enhanced diagnostic activity in individuals aged 40-49 years appears to have led to earlier detection rather than increased advanced disease. These observations do not provide evidence that would support lowering the current starting age of organized screening. Rising CRC incidence in individuals aged 30-39 years warrants increasing clinical vigilance in younger adults with symptoms or elevated risk and requires further investigation into underlying drivers. Epidemiologic surveillance should preferably include precursor lesions and diagnostic activity.

Background/Objectives: This population-based study examined epidemiological trends of primary cancers in adolescents and young adults (AYA) to enhance the understanding of the specific spectrum of cancers impacting AYA in Belgium. Methods: Data on incidence, prevalence, mortality, and survival were obtained from the Belgian Cancer Registry (2004–2020, N=43,535). (A)APC statistics were compared with children (5–14 years) and adults (40–49 years). Results: Cancer incidence increased by 0.4% annually from 66 to 80 per 100,000 person-years (ESR2013) but stabilized after 2015, except for Hodgkin lymphoma, chronic myeloid neoplasms, testicular, and breast cancer, which continued to rise. Mortality decreased by 1% annually, from 10 to 7 per 100,000 person-years (2004–2019). Five-year relative survival (RS) was 87% but remained low for certain cancers, including ovary (78%), central nervous system (67%), precursor haematopoietic neoplasms (64%), gastrointestinal (excl. colorectal) (49%), and lung-bronchus-trachea cancers (42%). Conclusions: From 2004–2020, the cancer burden among AYAs in Belgium increased due to improved survival, while incidence stabilized after 2015. Five-year RS exceeds 80% overall but remains lower for some cancers compared to children (e.g., precursor haematopoietic neoplasms) or older adults (e.g., breast cancer, sarcoma). The Belgian epidemiological trends align with those in neighbouring countries (Netherlands, France, Germany).