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 Get Data Out tables for the 2023 release of data about tumours of the kidney (excluding renal pelvis) between 2013 and 2020.

Kidney tumour cohort

The cohort of kidney tumours used for Get Data Out aims to be all registrable tumours of the kidney, excluding tumours of the renal pelvis, and excluding tumours whose morphology suggests they are tumours of the renal pelvis that have been miscoded (ie all transitional cell carcinomas).

This has been coded as

Transitional cell cancers (TCC) (ICD-O-3.1 8120, 8122, 8130 or 8131) of kidney are excluded, these are assumed to be miscoded renal pelvis tumours and are included in the bladder partition.

Notes:

ICD-10 code D09.1 refers to “Carcinoma in situ of other and unspecified urinary organs”; in order to identify the specific site of these tumours we also refer to ICD-O-3.1 site which gives the location of the tumour, hence allowing us to include these tumours in the cohort within the correct site.

Transitional cell carcinomas (ICD-O-3.1 8120, 8122, 8130 or 8131) are a morphology type that usually occurs in the renal pelvis, and does not occur in the main body of the kidney. However, as the renal pelvis is physically inside the kidney, historically these tumours have been miscoded to the kidney. Validations now exist on the NCRAS system to prevent such registrations being made. However, some tumours have already been registered to kidney sites (C64 or D41.0 or (D09.1 with ICD-O-3.1 code C64)). For the purposes of this grouping, they have been included as if coded to the renal pelvis. These are at kidney sites with transitional cell carcinoma morphology: ICD-O-3 8120, 8122, 8130 or 8131. This problem has been solved in cancer registration data from 2017 onwards.

Tumour Type

The tumours are then split by the Tumour Type field, split into two groups by behaviour:

‘Malignant kidney cancers’ is all tumours coded to C64 in ICD 10.

As the D09.1’s are vanishingly rare (<5 a year) this group is called ‘Kidney tumours of uncertain behaviour’ for brevity. This group is not divided further.

Tumour Type 2 – Morphology

Malignant tumours are classified by morphology according to their ICDO3rev2011 morphology. Tumours are classified into six groups. Most morphologies are subtypes of Renal cell carcinoma (RCC).

This morphology grouping is created via a lookup produced by Brian Rous and QAed by the kidney group and the site specific kidney lead (see below for list of people involved).

If this morphology is missing (usually due to data quality issues like a missing classificationmappingID), their morphological type is treated as Renal cell carcinoma Not Otherwise Specified (NOS). (This affects <20 tumours over 5 years).

A full machine readable look-up is included in Appendix A

Basis of diagnosis

Renal cell carcinoma NOS (Not Otherwise Specified) may be NOS either because a distinct morphology cannot be seen under the microscope, or because the tumour has been clinically diagnosed and no tissue sample has been taken.

These two groups appear to be different, with different age profiles and stage profiles. Because of this, Renal cell carcinoma NOS is subdivided into two groups based on the basis of diagnosis, i.e. into:

Stage

The large groups of malignant tumours;

Are then split by stage.

The stage split is

Please note that the staging system for these kidney cancers changed from TNM 7 to TNM 8 between 2017 and 2018 diagnoses. We believe that this changing definition reduces the number of stage 2 tumours and increases the number of stage 3 tumours, and so care must be taken if analysing the GDO data as a time series – the decrease in stage 1-2 tumours is being driven at least in part by the coding artifact of the changing stage system.

The registration of 2019 tumours were being completed during the COVID-19 pandemic. This led to reduced access to the usual data sources, and despite the registry’s best efforts a noticeable decrease in data quality in some fields. This is most commonly seen in an increase in ‘stage unknown’ tumours, and a corresponding decrease in other stage groups. For Kidney tumours, this pattern can also be seen in 2018 as some cases registered in early 2019 were actually late 2018 cases. These cases subsequently also got affected by the repercussions of COVID-19 on the registry and has led to a larger than expected difference in 2018 ‘stage unknown’ tumours compared to GDO’s previous release. Furthermore, the data shows a larger than expected increase in all Kidney tumours diagnosed between 2018 and 2019. This is because 2019 cases have been artificially inflated compared to previous years as some of the ‘stage unknown’ Kidney tumours would have been referenced off as non-registerable cases if they were registered outside of the COVID-19 pandemic time period. Both of these influences need to be considered when undertaking time-series analysis on the data.

The vast majority of cases are staged in either the UICC 7 or UICC 8 system, where the recommended staging system changed from UICC 7 to UICC 8 between 2017 and 2018 diagnoses. A very small percentage of cancers (less than 1%, apart from UICC 6 which accounted for 1.178% of cases in 2013), were staged in other systems, as reported in the known limitations page. The following table shows the percentage of cases staged in each of UICC7 and UICC8 over time.

Age

The ideal is to split into:

This is possible for the larger groups.

If there are not enough people aged under 50, the lower limit is set at under 60. A group of 60-69 may then be used instead of 50-69. If there are not enough people under 60, the lower limit is set at under 70.

If there are not enough people aged over 80, the upper limit is set at 70+.

These splits were determined empirically by the size of the groups, and are summarised in this table below.

Cohort and classifications were created with a working group including Prof, Hardev Pandha, Professor of Medical Oncology at the University of Surrey, Sharon Deveson Kell, Head of Medical Relations at the Kidney Cancer Support Network, pathologist Dr Brian Rous and analysts Luke Hounsome and Nicola Cooper at NCRAS.

Appendix

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