Cancer survival: Index for sub-Integrated Care Boards, 2005 to 2020

These cancer survival estimates are designated as National Statistics, a subset of official statistics. They are assessed by the UK Statistics Authority as being compliant with its Code of Practice for Statistics.

The index of cancer survival provides a convenient, single number that summarises the overall pattern of cancer survival for each calendar year. It combines the net survival estimates for each gender, age group and:

• female breast cancer
• colorectal cancer
• lung cancer
• all other invasive cancers combined, excluding both prostate and non-melanoma skin cancers.

Individual estimates are all age-specific and standardised. Age- and gender- specific estimates are also provided for colorectal lung and female breast cancer; age-standardised estimates for colorectal and lung cancer are further standardised by gender. The age-standardisation weights are those specified in the International Cancer Survival Standard.

The data used in these analyses was extracted from the National Cancer Registration Dataset. All adults (aged 15 to 99 years) who were diagnosed with a first, primary, invasive malignancy (International Classification of Diseases, Tenth Revision (ICD10) C00-C97) were eligible for inclusion. Patients diagnosed with malignancy of the skin (ICD10 C44) other than melanoma were excluded. Cancer of the prostate (ICD10 C61) was also excluded from the index because the widespread introduction of prostate-specific antigen (PSA) testing since the early 1990s has led to difficulty in the interpretation of survival trends, as explained in the publication Excess cases of prostate cancer and estimated over diagnosis associated with PSA testing in East Anglia.

Net survival is an estimate of the probability of survival from the cancer alone excluding other potential causes of death. It is a variant of relative survival that is preferred as a measure of cancer survival in adults because it is an unbiased estimator. Net survival estimates the survival of cancer patients compared with the background mortality that patients would have experienced if they had not been diagnosed with cancer. The Cancer survival methodology documentation has more details on the methods used.

The net survival estimates in this publication are produced using a regression model. The data in the model is from adults diagnosed with cancer between 2005 and 2020. Patients are followed up to 31 December 2021 to see if or when they died in that period. Data is provided for a 16-year period because the method used requires data over a long period in order to give robust estimates and so that each area has a baseline against which to assess progress over time. The publication models the trend for each area separately. This means interpretation should focus on overall trends rather than on small changes in the survival index in a particular year.

It was sometimes impossible to produce robust estimates of survival for one or more of the age groups, most often because of the relatively small number of patients diagnosed in the youngest age group (15 to 44 years). In this situation, the missing value for a sub-ICB is replaced by the corresponding value for their “parent” Integrated Care Board (ICB) or, if that is also missing, the missing value for both the sub-ICB and ICB is replaced by the value for England. A single estimate of colorectal cancer for the age-group 55-64 in males, England required a synthesised estimate, which was obtained from a weighted average of the ICB estimates, which were available for all ICBs in this age-group. Similarly, any missing values for ICBs or Cancer Alliances are replaced by the value for England.

Research of population-based cancer survival trends in England and Wales found that survival for most cancers is either stable or rising steadily year on year. This trend is visible in the index of cancer survival. The index is designed to reflect real progress in cancer outcomes by long-term monitoring of progress in overall cancer survival. It provides a summary measure of cancer survival that takes account of differences in the proportions of cancers in each geography. For example, female breast cancer is more frequently diagnosed at stages 1 and 2 than lung cancer. Therefore, without standardising for cancer site, sub-ICBs with a higher-than-average occurrence of female breast cancer will tend to have higher survival, compared to sub-ICBs with a higher-than-average occurrence of lung cancer.

For geographic areas with small populations, like most sub-ICBs, some fluctuations in survival estimates between consecutive years should be expected, as reported in cancer survival indicators for Clinical Commissioning Groups in England. These fluctuations primarily occur due to the small numbers of cancer diagnoses and deaths each year within the population.

Interpretation should focus on long-term trends, rather than the survival estimate for a particular year. Geographical areas for which the index of cancer survival is consistently lower than the estimate for England may warrant further investigation.

The aim of this publication is to present data that can support the monitoring of long-term improvements in cancer control. These estimates can indicate the potential for improvement in the management of cancer, from early detection through to referral, investigation, treatment and care. Survival estimates should not be used as the sole indicator of an area’s performance in cancer outcomes. To gain a more complete picture of the cancer burden in a geographical area, these estimates should be used alongside other information available, such as cancer incidence and mortality data.

The survival estimates must be interpreted with care. They do not reflect the survival prospects for any individual cancer patient; they represent the net survival for all cancer patients in each area, in a given period of time, diagnosed with a specified type of cancer.

Survival is estimated using the most up-to-date boundaries at publication. A sub-ICB, ICB or CA is not responsible for trends in cancer survival that pre-date its existence.

The geographies, as at July 2022, covered by this publication are:

• the 106 sub-ICBs in England
• the 42 ICBs in England
• the 21 CAs in England
• England

These survival estimates are based on patients living within defined sub-ICB boundaries at the point of diagnosis. However, the structure of sub-ICBs means they are responsible for patients registered at primary care (GP) practices within their boundary. This may result in some differences between the patients included in these survival estimates and the patients for which the sub-ICBis responsible. This potential limitation is discussed in the article: Dismantling the signposts to public health? NHS data under the Health and Social Care Act 2012.