Cancer Survival in England, cancers diagnosed 2015 to 2019, followed up to 2020

This publication defines cancer using the International Statistical Classification of Diseases, 10th Revision (ICD-10).

Adult cancer patients often die from causes unrelated to their cancer diagnosis. To show only the effect of cancer deaths on survival, adult survival estimates are net survival estimates. Net survival estimates compare the survival of cancer patients with that of the general population.

Childhood cancer survival estimates are overall survival estimates. Comparisons to the general population are not needed for childhood cancer patients. This is because death of a child within 10 years of a cancer diagnosis is almost always due to their cancer diagnosis.

The datasets present age-standardised estimates for adults by gender, stage and deprivation quintile and childhood cancer. Age-standardisation allows comparisons between population groups and over time. To age-standardise, the adult estimates use the International Cancer Survival Standard weightings with 5 age groups. The childhood estimates are age-standardised by giving equal weight to each age group (0 to 4, 5 to 9 and 10 to 14 years). All age groups must pass robustness tests to present an age-standardised estimate.

If estimates fail the quality tests for more than 2 of the 5 age groups or 2 non-adjacent age groups, it is not possible to present age-standardised estimates. If a single age group or 2 adjacent age groups fail the quality tests, a combined age group is formed with an adjacent age group. The combined age group is re-tested for statistical quality. If the statistical quality tests are now passed, an age-standardised estimate using 4 age groups may be presented.

Using net survival methods, survival greater than 100% can occur if the survival experience in cancer patients is greater than the survival experience of the general population. For example, a high proportion of breast cancers are screen-detected and women who attend screening have on average better health status, therefore are less likely to die from non-cancer causes than the general population.

The datasets also present confidence intervals at the 95% level. A confidence interval is a range of values that is used to quantify the imprecision in the estimate of an indicator. A wider confidence interval shows that the indicator value presented is likely to be a less precise estimate of the true underlying value.

The Cancer survival methodology documentation has more details on the methods used. A detailed impact paper of methodology changes for cancer survival accompanies this release.

The cancer registry records self-stated gender at diagnosis and not sex assigned at birth. Due to small numbers and the risk of disclosure, we are unable to present survival estimates for males with cancers of organs such as the uterus, cervix and vagina, or females with cancers of the prostate, testes and penis.

The staging system used here is typically TNM. The TNM system puts cancers in a group from 1 to 4 depending on the cancer, or tumour, size (T); which, if any, lymph nodes have cancer cells (N); and if the cancer has spread (metastasised) to other parts of the body (M). Different versions of TNM are used (versions 5 (for colorectal), 7 and 8), in line with international guidance. For some cancers, a site/group-specific staging system is used instead of TNM:

• International Federation of Gynaecology and Obstetrics (FIGO) staging for gynaecological (ovary, cervical and uterus) cancers
• Ann Arbor staging for non-Hodgkin lymphomas
• International Staging System (ISS) for myelomas
• Binet staging for chronic lymphocytic leukaemia (CLL)
• Chang staging for Medulloblastoma
• International Neuroblastoma Risk Group staging system (INRGSS) for neuroblastoma
• National Wilms Tumour Study staging for Wilms tumours.

For these cancer sites/groups, TNM stage has been used where the site/group-specific stage was unknown. Cervical cancer is the exception, whereby a cancer is only considered staged if a FIGO staging value is available.

For the 23 cancer sites with reported survival by stage estimates in 2015 to 2019, there is a known stage for 86.3% of diagnoses. Due to the impact of the COVID-19 pandemic on the National Disease Registration Service (NDRS) workforce and working arrangements, cancer registrations were delayed for the 2019 registrations, and there was a slight decrease in staging completeness.

It is possible that changes in the quality of staging data could cause overall increase or decrease in the proportion of diagnoses in each stage and therefore survival estimates by stage would be affected. Until the proportion of unknown stage is stable, we would caution against comparing the proportions of individual stages at diagnosis or their survival estimates over time.