The Get Data Out programme routinely publishes cancer statistics produced by NHS D (previously PHE) in a consistent table, called the Get Data Out (GDO) table. This table collects patients into groups with common characteristics, and then publishes information such as incidence, treatment rates, survival and Routes to Diagnosis for these groups.

This document sets out the definitions of the cohort and groups for the Get Data Out tables for the 2022 release of data on skin tumours diagnosed between 2013 and 2019.

Please note that the treatment statistics for certain skin tumours, namely keratinocyte cancers (BCC and cSCC), are currently experimental and likely undercount surgical tumour resections. NDRS is working on improving the methodology to identify skin surgical treatments using additional data sources, and hopes to include the improved methodology in the next data release.

Skin tumour cohort

The cohort of skin tumours used for Get Data Out is defined by ICD 10 site codes, and then further partitioned by ICD O-3rev1 morphology and behaviour codes.

The cohort is

  1. all registered tumours from 2013-2019 with an ICD 10 site code in the table “Skin site” (see Appendix), which is approximately all melanomas and non-melanomas of skin, all external skin of genitals, and all external skin of lip, i.e. all cutaneous skin, and also mucosal skin of the external genitals. This inclusion of external genitals and external lip is a wider definition of skin than is seen in some other cancer statistics.

  2. all subsequent BCCs and cSCCs of skin from 2013-2019 as identified as proxy registrations from pathology reports. The cancer registry only fully registers the first Basel Cell Carcinoma (BCC) and Squamous Cell Carcinoma (cSCC) of skin. A standard methodology is followed to identify later BCCs and cSCCs, based primarily on pathology reports received by the registry. (This methodology is documented in the ‘How to Count Skin Cancer’ SOP, and in the paper ‘Epidemiology of basal and cutaneous squamous cell carcinoma in the U.K. 2013-15: a cohort study. Z. Venables, Br J Dermatol. 2019’.) These proxy cases are important to fully understand the true incidence of keratinocyte cancers, as many patients have multiple tumours.

Tumour types within the cohort are assigned using ICD O-3rev1 morphology and behaviour codes, see Appendix “O-3 morphology and behaviour”.

ICD 10 site codes and ICD O-2 morphology and behaviour codes are used to identify types of tumour from 1995-2013, to correctly identify the ‘first’ tumour where needed. See Appendix “O-2 morphology and behaviour”.

Year

The cohort is first split by the year of diagnosis.

Tumour Type 1

Tumours are classified based on morphology and behaviour as coded in ICD-O-3 into:

Extramammary Paget disease is coded as behaviour 3 in ICD-O-3 but is viewed by the British Association of Dermatologists (BAD) as a pre-invasive skin tumour, and so is not included in the main ‘Skin cancer’ grouping.

Tumour Type 2

Melanoma in situ is further classified into:

Skin cancer is further classified into:

Skin tumours of uncertain malignant potential are further classified into:

All these classifications are made on ICD-O-3 morphology and behaviour.

Tumour Type 3

Keratinocyte cancer is further classified into:

Rare cancer is further classified into:

These classifications are made on ICD-O-3 morphology and behaviour (see Appendix).

Melanoma is further classified into:

This classification is made on ICD10 site codes (see Appendix).

Tumour Type 4

Lentigo maligna and other melanoma in situ are classified into broad site groupings:

These classifications are based on ICD10 site codes (see Appendix, site_group_1).

Tumour Type 5

BCC and cSCC are further classified into:

These classifications are made on ICD10 site codes (see Appendix).

Non-genital melanoma is further classified into:

Appendageal (adnexal) is further classified into:

These classifications are made on ICD-O-3 morphology and behaviour (see Appendix).

Sex

For genital cSCCs, sex is the next split, as tumours of the penis and vulva have different staging systems and may present differently.

For other skin cancers, where a sex split is possible it occurs further down the tree and so is described later in this document.

Tumour Type 6

Non-genital BCC and Non-genital cSCC are further classified into:

Because only first tumours are fully registered, and subsequent tumours are usually imputed from pathology reports, (using methodology as documented in the ‘How to Count Skin Cancer’ SOP, and in the paper “Epidemiology of basal and cutaneous squamous cell carcinoma in the U.K. 2013–15: a cohort study. Z. Venables, Br J Dermatol. 2019”) the data quality of subsequent tumours is poor, and they are generally not included in international incidence rates. Partitioning the tumours into ‘first’ and ‘subsequent’ enables comparisons with other international statistics and also produce groups of ‘first’ tumours where the data quality is robust enough for further analysis.

Patients are identified as registrations with the same patientID. The first tumour is the tumour registered with the earliest diagnosis date, from 1995 onwards. All tumours registered or imputed with later diagnosis dates are included in the ‘subsequent tumour’ group. The methodology only allows one tumour per individual in each year.

First and subsequent tumours are identified within the tumour type - a patient diagnosed with both BCCs and cSCCs will have two ‘First tumours’. More details on this can be found in the ‘How to Count Skin Cancer’ SOP.

BCCs and cSCCs in years that are not registered in ICD O3rev1 are identified using their ICD O2 morphology and behaviour (See Appendix “O-2 morphology and behaviour”). For years where both coding systems are available, the cohorts selected by the two look-ups agree exactly for BCCs and cSCCs.

As subsequent tumours do not result in a full tumour record some of the output statistics are not available for these groups - the methodology might be inappropriate, and data quality is poor.

Age 1

The first age breakdown for the main skin cancer groups aims to separate off a small group of ‘young’ skin cancer patients from the majority of skin cancer patients. The age cut off is chosen to make a group of approximately the right size for Get Data Out statistics.

Common melanoma is classified into:

First BCC is classified into:

Subsequent BCC is classified into:

First cSCC is classified into:

Subsequent cSCC is classified into:

For other skin cancer sites that only have one age breakdown, the age breakdown is determined by the age profile of the cancer to make appropriately sized groups.

Lentigo maligna at the head, face and scalp, and other melanoma in situ at the trunk or limbs or not known are further classified into:

Lentigo maligna at the trunk or limbs or not known, and other melanoma in situ at the head, face and scalp are further classified into:

Atypical fibroxanthoma (AFX) and atypical fibrous histiocytoma (AFH) is further classified into:

Sweat gland tumours are classified into:

Stage

Common melanoma - age 25 years and older is further classified into:

Merkel cell carcinoma is further classified into:

Some of the Merkel cell carcinoma stage groups contain a small number of patients. To protect patient privacy, only incidence will be published for these groups. Instead, 3-year non-rolling data for the other statistics (survival, treatment, etc.) will be published, starting from 2013-2015.

Female genital cSCC tumours are further split into:

Male genital cSCC tumours are further split into:

Scrotal tumours are staged differently than the other male genital tumours, for this reason scrotal tumours are designated ‘Stage not applicable’ in this split.

Tumour Type 7

Melanoma stage 1, 2, 3, and unknown are further classified into:

These classifications are made on ICD10 site codes (see Appendix, site_group_1).

First BCC aged 25+, subsequent BCC aged 40+, first cSCC aged 40+, and subsequent cSCC aged 60+ are further classified into:

These classifications are made on ICD10 site codes (see Appendix, site_group_2).

Age 2

For common melanoma that has been grouped by stage and site, further age splits are possible.

Sites from stage 1 are further classified into:

Sites from stage 2 and stage unknown, and from stage 3 where numbers allow are further classified into:

For BCC and cSCCs in patients aged over 25 that have been split by cancer site, further age splits are also possible.

Sites from first BCC 25+ are further classified into:

Sites from subsequent BCC 40+ are further classified into:

Sites from first cSCC 40+ are further classified into:

Sites from subsequent cSCC 60+ are further classified where numbers allow into:

Where numbers allow stages from genital cSCC tumours are split into:

Region

Where numbers allow the cohort is partitioned into 7 regions:

Patients are assigned to a region by their postcode at diagnosis and the National Statistics Postcode Lookup. Regions are defined based on the NHS regions in 2019.

Sex

The following previous groups are split by sex into male and female:

Lentigo maligna and other melanoma in situ, after splitting by body site 1 and age 1, are further split by sex.

Where numbers allow age groups derived from common melanoma stage 1, 2, 3, and unknown are further split by sex.

Where numbers allow BCCs and cSCCs that have already been partitioned into regions are further split by sex.

(As discussed previously Genital cSCC tumours are split by sex into male and female.)

Appendix

ICD 10 codes included in this cohort and their subgroups

ICD O-2 morphology and behaviour codes included in this cohort and their subgroups

ICD O-3 morphology and behaviour codes included in this cohort and their subgroups