Cancer survival: Index for Clinical Commissioning Groups, 2004 to 2019

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:

• breast cancer diagnosed in women
• colorectal cancer
• lung cancer
• all other invasive cancers combined, excluding both prostate and non-melanoma skin cancers

The individual trends for breast (females only), colorectal and lung cancer are also presented in this publication. These individual estimates are all age-standardised, estimates for colorectal and lung cancer are further standardised by gender. Age-specific estimates are also provided for the index. Age- and gender-specific estimates are provided for breast, colorectal and lung cancers.

The data used in these analyses was extracted from the National Cancer Registration Dataset on 05 January 2022. 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. A detailed impact paper of methodology changes for cancer survival accompanies this release.

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 2004 and 2019. Patients are followed up to 31 December 2020 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 CCG is replaced by the corresponding value for their ‘parent’ CA or, if that is also missing, the missing value for both the CCG and CA is replaced by the value for England. Similarly, any missing values for STPs are replaced by the value for England. Details of cases where replacements are necessary are available in the data tables.

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, breast cancer is more frequently diagnosed at stages 1 and 2 than lung cancer. Therefore, without standardising for cancer site/group, CCGs with a higher than average occurrence of breast cancer will tend to have higher survival, compared to CCGs with a higher than average occurrence of lung cancer.

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

For geographic areas with small populations, like most CCGs, 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 – in 2021, the number of CCGs fell from 135 to 106 . A CCG, STP or CA is not responsible for trends in cancer survival that pre-date its existence.

The geographies covered by this publication are:

• the 106 CCGs in England
• the 42 STPs in England
• the 21 CAs in England
• England

These survival estimates are based on patients living within defined CCG boundaries at the point of diagnosis. However, the structure of CCGs 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 CCG is 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.