Cancer trends in England in younger adults from 2001-2023: comparing incidence, mortality and stage at diagnosis

Technical Summary: Cancer Trends in England in Younger Adults (2001–2023)

Problem Statement
Cancer incidence rates are rising for several malignancies among younger adults in the UK. While recent US studies have compared incidence and mortality trends, suggesting that mortality increases parallel incidence for specific cancers (e.g., colorectal and endometrial) but not others, there is a need for comprehensive, stage-stratified analysis within the English population. Previous UK studies have either focused on broader age ranges (35–69 years) or failed to differentiate trends between younger and older adults. Furthermore, it remains unclear whether rising incidence rates in younger adults are driven by early-stage disease (potentially indicating overdiagnosis or surveillance artifacts) or late-stage disease (indicating a true increase in aggressive disease burden). This study addresses these gaps by analyzing national data to compare incidence, mortality, and stage-at-diagnosis trends for cancers increasing in younger adults (aged 20–49) in England.

Methodology
The authors utilized cancer incidence and mortality data from the English National Disease Registration Service (NDRS) covering the period 2001–2023. The year 2020 was excluded due to potential under-reporting during the COVID-19 pandemic.

• Population: The analysis focused on adults aged 20–49 (younger) and 50–79 (older).
• Cancer Selection: The study identified 12 specific cancers with increasing incidence in younger adults and more than 500 cases diagnosed in 2023: female breast, colorectal, melanoma, thyroid, kidney, leukaemia, oral, brain, Hodgkin lymphoma, ovarian, endometrial, and prostate cancer.
• Statistical Analysis: Trends were quantified using Joinpoint regression to estimate Average Annual Percentage Changes (AAPC) and 95% confidence intervals. Age-standardised rates (ASRs) were calculated using the European population in 2000.
• Stage Analysis: Cancer stage data (classified as early-stage [1–2] and late-stage [3–4]) was available from 2013–2023 for ten of the twelve cancers. Due to missing data patterns and pandemic-related artefacts, stage trends were compared between two specific time points: 2013 and 2023.
• Sensitivity Analyses: To address high proportions of unstageable/missing data (up to 55% for some cancers), the authors conducted sensitivity analyses by reclassifying all missing stage data as either early-stage or late-stage to test the robustness of observed trends.
• Excess Cases: The study estimated the excess number of cancer cases in 2023 compared to 2001 by applying 2001 age-standardised rates to the 2023 population structure.

Key Results

• Burden: In 2023, there were 31,385 cancer diagnoses in younger adults (20–49) compared to 244,384 in older adults (50–79). The most common cancers in younger adults were female breast (n=8,504), colorectal (n=2,977), and melanoma (n=2,767).
• Incidence vs. Mortality Trends (2001–2023): Among the 12 cancers with increasing incidence in younger adults, only two showed parallel increases in mortality:
  • Endometrial Cancer: Incidence AAPC 2.9% (95% CI 2.4–3.4%); Mortality AAPC 4.0% (95% CI 2.1–6.0%).
  • Colorectal Cancer: Incidence AAPC 3.2% (95% CI 2.8–3.6%); Mortality AAPC 1.9% (95% CI 1.1–2.7%).
  • For the other 10 cancers (including breast, testicular, ovarian, kidney, brain, prostate, Hodgkin lymphoma, and leukaemia), incidence rates increased while mortality rates decreased or remained stable.
• Stage-Specific Trends (2013–2023):
  • Both Early and Late-Stage Increases: Observed for colorectal and endometrial cancers.
  • Late-Stage Only Increases: Observed for female breast, ovarian, melanoma, and Hodgkin lymphoma.
  • Early-Stage Only Increases: Observed for thyroid cancer.
  • Mixed Patterns: Kidney, testicular, and prostate cancers showed increases in both early and late-stage disease.
• Absolute Numbers: While incidence rates are rising, the absolute number of additional diagnoses in 2023 compared to 2001 was 6,034, with 64% occurring in females. The largest absolute increases were in colorectal (n=1,604) and thyroid cancer (n=1,228). Despite rising rates, the absolute number of deaths in younger adults remains small compared to older adults (4,821 vs. 79,093 in 2023).

Significance and Claims
The authors claim this is the first analysis of cancer rate trends by stage specifically for younger adults in England. The study highlights distinct public health and research priorities based on three observed patterns:

1. Colorectal and Endometrial Cancers: The concurrent increase in incidence, mortality, and both early- and late-stage disease suggests these trends are unlikely to be explained solely by increased surveillance or early detection. The authors identify the need to investigate the causes of these increases, particularly for colorectal cancer, which is now the second leading cause of cancer death in younger adults.
2. Breast Cancer: As the most common cancer and leading cause of cancer death in younger adults, the finding that incidence is increasing only for late-stage disease (despite decreasing overall mortality) suggests that increased screening is not the primary driver. This warrants further research into the underlying causes to prevent future mortality rises.
3. Thyroid Cancer: The increase in incidence limited to early-stage disease with stable mortality is consistent with overdiagnosis due to increased surveillance.

The paper concludes that while advances in treatment have likely contributed to decreasing mortality for many cancers with rising incidence (e.g., breast, testicular), the increases in late-stage disease for several malignancies are concerning and could reverse favorable mortality trends. The authors emphasize the need for in-depth investigation into cancers showing concurrent increases in incidence, mortality, and late-stage disease.