The incidence date is the date of the first histological or cytological confirmation of the tumour. It cannot be later than the start of treatment. If treatment begins before histological confirmation, the incidence date is the date of clinical diagnosis. It must always fall within three months of the first clinical visit related to this tumour.
The incidence date is the date of the first histological or cytological confirmation of the tumour. It cannot be later than the start of treatment. If treatment begins before histological confirmation, the incidence date is the date of clinical diagnosis. It must always fall within three months of the first clinical visit related to this tumour.
Patient data
ink_ses
Median income in postal code area as a proxy for socioeconomic status (SES)
Available from 2010. Socioeconomic status (SES) reflects an individual's social position, which strongly influences health and is linked to life expectancy in good health. Research on SES and health typically uses indicators such as education, income, occupation, and material wealth. This variable uses income as a proxy for SES.
Income data by postal code area were obtained from Statistics Netherlands (CBS), with 2019 as the reference year, downloaded on 16 October 2023 via https://www.cbs.nl/nl-nl/dossier/nederland-regionaal/geografische-data
/gegevens-per-postcode.
Income is defined as the median disposable household income, adjusted for household size and composition. For each area, the median standardised household income was compared to the national distribution and classified into one of five groups: low, lower-middle, middle, upper-middle, or high. Income thresholds (in euros) are available at: https://www.cbs.nl/nl-nl/longread/diversen/2023/statistische-gegevens-per-vierkant-en-postcode-2022-2021-2020-2019/4-beschrijving-cijfers. Because postal code areas often have few households, CBS also
considered the 99% confidence interval of the median income. If this interval spans multiple groups, a new category was created to reflect the range (e.g., 'low to lower-middle'). Categories may partially overlap due to this approach. If the median income is based on fewer than 10 households, it is classified as 'unclassifiable'. CBS originally defined 12 income categories.
For this variable, these were reduced to three to simplify analysis and remove overlaps.
Key considerations:
- Income is a snapshot and does not reflect accumulated wealth.
- Data are aggregated by postal code area, which may include substantial variation.
- Household income is strongly age-dependent; analyses should compare individuals within the same age group.
- Median disposable income is considered valid for up to 10 years before and after the reference year (2019).
Selection of malignancies to specify in the request:
-Period: Previous and/or subsequent malignancies, or based on a defined timeframe before or around the incidence date.
-Type: All cancer types in the NCR, or all malignant/invasive (excluding skin BCC), or a selection of specific tumour types.
NKR database content with full availability:
Period: Nationwide complete from 1989.
Exclusion criteria:
- Patients residing abroad at the time of incidence
- Basal cell carcinomas of skin and lip
- Second primary invasive and second non-invasive squamous cell carcinomas of the skin
- Adenocarcinoma in situ/high-grade dysplasia of colon, rectosigmoid and rectum
- Carcinoma in situ of the cervix
- Benign/borderline tumours, except: CNS tumours from 2001, Borderline ovarian tumours, AL amyloidosis from 2017, Polymorphic PTLD
Refers to the NCR tumour classification based on site, morphology, and behaviour. For more information, see: https://iknl.nl/nkr/registratie/tumorindeling
Once a year, at the end of the first quarter, the NCR is linked to the Municipal Personal Records Database (GBA). The GBA is complete up to February of that year. Vital status reflects the status up to this date. For patients listed as alive in the GBA, the vital status date is the date up to which the GBA is complete. If a patient is recorded as deceased or emigrated, the vital status date is the date of death or emigration. Using this date and the incidence date, the interval between incidence and vital status (in days) is calculated.
Once a year, at the end of the first quarter, the NCR is linked to the Municipal Personal Records Database (GBA). The GBA is complete up to February of that year. Vital status reflects the status up to this date. For patients listed as alive in the GBA, the vital status date is the date up to which the GBA is complete. If a patient is recorded as deceased or emigrated, the vital status date is the date of death or emigration. Using this date and the incidence date, the interval between incidence and vital status (in days) is calculated.
Once a year, at the end of the first quarter, the NCR is linked to the Municipal Personal Records Database (GBA). The GBA is complete up to February of that year. Vital status reflects the status up to this date. For patients listed as alive in the GBA, the vital status date is the date up to which the GBA is complete. If a patient is recorded as deceased or emigrated, the vital status date is the date of death or emigration. Using this date and the incidence date, the interval between incidence and vital status (in days) is calculated.
The TNM classification uses the edition applicable at the time of incidence.
Meaning of the last character in pN:
S: Result based only on sentinel node examination (sn)
I: Isolated tumour cells (ITC)
M: Micrometastases (mi)
cstadium: The clinical stage is based on cTNM, which is derived from information available before (neo-adjuvant) treatment, including findings during surgery (if not treated neo-adjuvantly) that influence the treatment plan. Meaning of "X" (unknown): Stage cannot be calculated, e.g., TX/NX/M0. Meaning of "M" (missing): Indicates TNM not recorded, possibly due to incomplete registration or use of EoD staging instead of TNM. Meaning of "NVT" (not applicable): TNM staging does not apply to this tumour type for the given incidence period.
The TNM classification uses the edition (UICC) valid at the time of incidence:
1989–1992: 4th edition (TNM 4),
1993–1998: 4th edition, 2nd revision (TNM 4),
1999–2002: 5th edition (TNM 5),
2003–2009: 6th edition (TNM 6),
2010–2016: 7th edition (TNM 7),
2017–2014: 8th edition (TNM 8),
and from 2025: 9th edition (TNM 9).
pstadium: The pathological (post-surgical) stage is based on pT, pN and pM. In cases of pre-surgical therapy,
ypT and ypN are used. If no tumour remains after pre-surgical therapy, this is recorded as stage p=0.
pM: Indicates whether there is pathological confirmation of distant metastases. There may be distant metastases that are not pathologically confirmed, which are therefore not included in the calculation for this variable.
Meaning of "X" (unknown): Stage cannot be calculated, e.g., TX/NX/M0.
Meaning of "M" (missing): Indicates TNM not recorded, possibly due to incomplete registration or use of EoD staging instead of TNM.
Meaning of "NVT" (not applicable): TNM staging does not apply to this tumour type for the given incidence period.
The TNM classification uses the edition (UICC) valid at the time of incidence:
1989–1992: 4th edition (TNM 4),
1993–1998: 4th edition, 2nd revision (TNM 4),
1999–2002: 5th edition (TNM 5),
2003–2009: 6th edition (TNM 6),
2010–2016: 7th edition (TNM 7),
2017–2014: 8th edition (TNM 8),
and from 2025: 9th edition (TNM 9).
Stadium: Based on pTNM supplemented by cTNM to best reflect the actual stage at diagnosis. Priority is given to
pTNM values. If surgery did not occur, pTNM is unknown, or pre-surgical therapy was given (pTNM becomes ypTNM), cTNM values are used.
Meaning of "X" (unknown): Stage cannot be calculated, e.g., TX/NX/M0.
Meaning of "M" (missing): Indicates TNM not recorded, possibly due to incomplete registration or use of EoD staging instead of TNM.
Meaning of "NVT" (not applicable): TNM staging does not apply to this tumour type for the given incidence period.
Non-microscopic confirmation:
0 = death certificate only
1 = clinical examination only (medical history and physical)
2 = clinical diagnostic tests, exploratory surgery or autopsy (without microscopic confirmation)
4 = specific biochemical and/or immunological laboratory tests.
Microscopic confirmation:
5 = haematological (bone marrow cytology, e.g., bone marrow aspiration, blood smear) or cytological confirmation of primary tumour or metastases, or definite microscopic confirmation but unclear whether cytology or histology
6 = histological confirmation of metastases only, including at autopsy
7 = histological confirmation of primary tumour, or unclear whether histology refers to primary tumour or
metastasis, including autopsy with histology.
Available for 2020–2022. Refers to the lung diffusion capacity for carbon monoxide (DLCO). The measured value is expressed as a percentage of the predicted value for a healthy individual. DLCO depends on sex, age, height and haemoglobin level.
Available for 2020–2022. Refers to the forced expiratory volume in one second (FEV1) measured from total lung capacity, expressed as a percentage of the predicted normal value. This predicted value depends on factors such as sex, age and height.
Available from 2015. Refers to the maximum clinical diameter of the primary tumour as measured on CT, or on PET(/CT) if no CT was available. For multifocal tumours, the size of the largest lesion is recorded.
Tumour data
longtum_voor_int
Interval between the incidence date of the previous primary lung tumour and the current tumour (days)
If there are multiple primary lung tumours in the patient's medical history, the interval shown here is calculated from the most recent lung tumour prior to the current lung tumour. All previous lung cancer diagnoses are taken into account, up to the day before the current lung tumour. The NCR is complete from 1989 onwards, so incidences before that year may potentially be missed.
The incidence dates correspond to the dates of the first histological or cytological confirmation of the primary tumours.
Indicates whether a primary lung tumour occurred prior to the lung tumour under study. All previous lung cancer diagnoses up to the day before the current diagnosis are considered. The NCR is complete from 1989 onwards, so earlier incidences may be missed.
The incidence date is defined as the date of the first histological or
cytological confirmation of the primary tumour.
The metastasis date refers to the first histological or cytological confirmation of the
metastasis. If histological confirmation does not occur within three
months, the clinical diagnosis date is used. Consequently, the
metastasis date may precede the primary tumour incidence date by up
to three months.
Metastasis location according to ICD-O-3. Metastatic sites have been recorded nationwide since 2008. For distant metastases at more than three sites, C768 was coded up to 2014 to indicate more than three locations. In 2017/2018 C768 may indicate more than four locations.
Explanation for records where both cM and pM show no metastases despite metastatic sites being recorded at diagnosis: cTNM is based on information available before (neo-adjuvant) treatment, including findings during surgery (if not treated neo-adjuvantly) that influence the treatment plan. pM indicates whether pathological
confirmation exists for distant metastases. If metastases are detected during or after neo-adjuvant treatment, TNM is not updated, but metastasis locations are recorded.
If the dataset includes metastasis locations after progression: only new or enlarged metastases are recorded, not all existing ones. C809 is coded for clinical progression when the site is unknown.
Metastasis location according to ICD-O-3. Metastatic sites have been recorded nationwide since 2008. For distant metastases at more than three sites, C768 was coded up to 2014 to indicate more than three locations. In 2017/2018 C768 may indicate more than four locations.
Explanation for records where both cM and pM show no metastases despite metastatic sites being recorded at diagnosis: cTNM is based on information available before (neo-adjuvant) treatment, including findings during surgery (if not treated neo-adjuvantly) that influence the treatment plan. pM indicates whether pathological
confirmation exists for distant metastases. If metastases are detected during or after neo-adjuvant treatment, TNM is not updated, but metastasis locations are recorded.
If the dataset includes metastasis locations after progression: only new or enlarged metastases are recorded, not all existing ones. C809 is coded for clinical progression when the site is unknown.
Metastases diagnosed prior to progression and up to a maximum of 91 days after the incidence date of the primary tumour.
Metastatic sites have been recorded nationwide since 2008 – before that time, metastases may have been known but not registered. Therefore, this variable is defined from incidence year 2008 onward.
A number of mutations qualify, depending on staging, for treatment with targeted therapy. However, treatment guidelines have changed over the years. This variable indicates whether, for the mutation in question, targeted therapy was available as standard treatment in the respective year. It is possible, however, that such medication was already used earlier, for example as part of clinical trials or an expanded access program.
Note: use this classification with caution. Especially for the less specific categories (for example 5 (BRAF) and 61 (MET)), subvariants may also have been coded under these categories for which it later turned out/or will turn out that they are not effectively treatable with targeted therapy. In general, mutation-informed tumour-directed treatment is still rapidly evolving.
Available since 2015.
The pathological measurement of the primary tumour based on lung surgery. Only the invasive component of the tumour is taken into account.
In the case of multiple lung surgeries, and therefore multiple pathology reports, this variable shows the maximum pathological tumour size.
Available since 2018.
When multiple PD-L1 tests have been performed, only the highest value is recorded.
Note: When a pathologist codes >50%, we record 50–89%. Therefore, the 50–89% group may include tumours that in reality have a score of 90–100%.
Synchronous multiple primary lung cancer (sMPLC) is defined as another primary lung cancer diagnosed within 90 days before or after the index diagnosis.
The first hospital visited by the patient for symptoms related to the malignancy, and where, based on that visit, a (suspected) malignancy is determined.
Available since 2015. The first hospital visited by the patient for symptoms related to the malignancy.
The incidence date is defined as the date of the first histological or cytological confirmation of the primary tumour.
This variable reports the most unfavourable result from any biopsies/aspirations taken during EUS. EUS has been routinely recorded in the NCR since around 2010.
Based on the date of the first MRI, or the first CT if no MRI was performed. Available from 2015. The incidence date is defined as the date of the first histological or cytological confirmation of the primary tumour.
Process data
mdo_voor_ther_dat
Date of the final multidisciplinary team meeting (MDT) before treatment commenced
Available since 2022.
In the case of multiple MDTs prior to therapy, this variable only shows the date of the last MDT.
For the start of therapy, this variable looks at all therapies: these may also include, for example, palliative treatments.
Available since 2022.
The incidence date is defined as the date of the first histological or cytological
confirmation of the primary tumour.
In the case of multiple MDTs prior to therapy, this variable only shows the date of the last MDT.
For the start of therapy, this variable looks at all therapies: these may also include, for example, palliative treatments.
Process data
mdo_voor_ther
Discussed in the multidisciplinary team (MDT) before starting treatment
Available since 2022.
In the case of multiple MDTs prior to therapy, this variable only shows the date of the last MDT.
For the start of therapy, this variable looks at all therapies: these may also include, for example, palliative treatments.
Available from 2023. Navigation during this bronchoscopy is CT-guided. If multiple navigation bronchoscopies were performed, only the final one conducted as part of the diagnostic process is recorded.
WHO performance status at the start of treatment. If the Karnofsky score was documented, it was converted to the WHO score according to Ma et al. 2010. Performance status has been recorded for lung cancer since 2015.
Determination of pre- and post-surgical therapy is based on the chronological order of procedures in the NCR. The first surgical resection is used as the reference point. Local surgical procedures (e.g. polypectomy, excision biopsy, TUR, photodynamic therapy, electrocautery, cryosurgery, radiofrequency ablation) are not included.
Systemic therapy drugs are recorded in the NCR using codes from the Anatomical Therapeutic Chemical classification system (ATC codes). Systemic therapy was not always recorded in detail; particularly before 2015, non-specific codes were used.
Applies only to chemotherapy and immunotherapy administered simultaneously: if both were given sequentially and there is no overlap, this is not considered chemo-immunotherapy (value 0).
In some cases, the start and/or end date of chemotherapy or immunotherapy is unknown, making it impossible to determine whether there was overlap; in that case, value 9 is displayed.
For registrations prior to 2018, the NCR commonly documented only the administration of systemic chemotherapy, without indicating the specific regimen. Consequently, this variable is more often coded as 9 (unknown) in earlier years.
Both chemotherapy and radiotherapy were part of the treatment, and based on the type and combination of both treatments, this likely represents chemoradiation. The chemotherapy and radiotherapy components also count towards the variables for systemic chemotherapy and radiotherapy.
Determination of pre- and post-surgical therapy is based on the chronological order of procedures in the NCR. The first surgical resection is used as the reference point. Local procedures (e.g. tumour destruction, excision biopsy, photodynamic therapy, electrocautery, cryosurgery, radiofrequency ablation) are not included.
Available since 2010
The incidence date is the date of the first histological or cytological confirmation of the primary lung tumour.
It concerns the interval in days to the start date of the first chemotherapy or radiotherapy treatment that is part of chemoradiation.
Available since 2010.
Treatment data
chemort_stop_int
Interval between incidence date and end date of chemoradiotherapy (days)
The incidence date is the date of the first histological or cytological confirmation of the primary lung tumour.
It concerns the interval in days up to the final end date of all chemotherapy and radiotherapy treatments that are part of chemoradiation.
Available since 2010.
Both chemotherapy and radiotherapy were part of the treatment, and based on the type and combination of both treatments, this likely represents chemoradiation. The chemotherapy and radiotherapy components also count towards the variables for systemic chemotherapy and radiotherapy.
The type of chemoradiation was determined by assessing whether chemotherapy and radiotherapy were administered overlapping (concurrent) or sequentially. It may occur that the start and/or end date of a treatment is missing. In such cases, the 30-day rule was applied: if there are 30 days or fewer between the start of chemotherapy and the start of radiotherapy, or between the end of chemotherapy and the end of radiotherapy, this is considered concurrent. A difference of more than 30 days is classified as sequential. When no start and/or end dates are available at all for determining overlap or applying the 30-day rule, value 9 (unknown) applies.
Within a single episode, multiple chemotherapy and radiotherapy treatments may occur, which may result in the presence of more than one type of chemoradiation. In such cases, the following prioritisation was applied: concurrent, unknown (as these cases may potentially also be concurrent),sequential.
Available since 2010.
Lung surgery performed with the aim of removing the primary tumour, excluding diagnostic procedures, incidental findings (see the variables related to other surgery), and additional resections.
Note: up to and including 2015, fewer details of surgical procedures were recorded in the NKR, which means it cannot always be determined whether a wedge resection was diagnostic or not. Therefore, in that period, it may occur that a diagnostic procedure is classified as lung surgery.
Lung surgery performed with the aim of removing the primary tumour, excluding diagnostic procedures, incidental findings (see the variables related to other surgery), and additional resections.
Note: up to and including 2015, fewer details of surgical procedures were recorded in the NKR, which means it cannot always be determined whether a wedge resection was diagnostic or not. Therefore, in that period, it may occur that a diagnostic procedure is classified as lung surgery.
Describes the final resection radicality determined on the basis of the last surgical procedure performed with the intention to remove the primary lung tumour.
Available from 2010. In the NCR, the distinction between robot-assisted surgery (RATS) and conventional thoracoscopic or video-assisted surgery (VATS) has only been recorded since 2018. Before that, both techniques were registered as scopic.
Lung surgery performed with the aim of removing the primary tumour, excluding diagnostic procedures, incidental findings (see the variables related to other surgery), and additional resections.
Note: up to and including 2015, fewer details of surgical procedures were recorded in the NKR, which means it cannot always be determined whether a wedge resection was diagnostic or not. Therefore, in that period, it may occur that a diagnostic procedure is classified as lung surgery.
Available from 2021 onward and only for stage IV tumours for which exclusively palliative radiotherapy was administered.
If no therapy has been performed at all, the variable geen_ther_reden can be consulted.
Determination of pre- and post-surgical therapy is based on the chronological order of procedures in the NCR. The first surgical resection is used as the reference point. Local procedures (e.g. tumour destruction, excision biopsy, photodynamic therapy, electrocautery, cryosurgery, radiofrequency ablation) are not included.
Systemic therapy drugs are recorded in the NCR using codes from the Anatomical Therapeutic Chemical classification system (ATC codes). Systemic therapy was not always recorded in detail; particularly before 2015, non-specific codes were used.
Treatment data
immuno_start_int[1-n]
Interval between incidence date and start date of systemic immunotherapy (days)[1-n]
Only the targeted therapies used in lung cancer with specific mutations - such as ALK, BRAF, or EGFR - are included.
Systemic therapy drugs are recorded in the NCR using codes from the Anatomical Therapeutic Chemical classification system (ATC codes). Systemic therapy was not always recorded in detail; particularly before 2015, non-specific codes were used.
Treatment data
mut_target_start_int[1-n]
Interval between incidence date and start date of mutation-directed targeted therapy (days)[1-n]
Defined as surgical procedures related to lung cancer, excluding resections intended to remove the primary tumour (see variables concerning lung surgery).
This variable concerns systemic targeted therapy, excluding immunotherapy and mutation-directed targeted therapy.
Systemic therapy drugs are recorded in the NCR using codes from the Anatomical Therapeutic Chemical classification system (ATC codes). Systemic therapy was not always recorded in detail; particularly before 2015, non-specific codes were used.
Defined as surgical procedures related to lung cancer, excluding resections intended to remove the primary tumour (see lung surgery variables). If multiple such procedures were performed, only the first is recorded.
Defined as cranial irradiation for patients without documented brain metastases, with the aim of reducing the risk of developing brain metastases.
Available nationwide from 2007.
The incidence date is the date of the first histological or cytological confirmation of the primary lung tumour.
If multiple PCIs have been performed, this variable reflects the interval to the end date of the first PCI.
Nationally available from 2007 onward.
Treatment data
pci_stop_int
Interval between incidence date and end date of PCI (days)
The incidence date is the date of the first histological or cytological confirmation of the primary lung tumour.
If multiple PCIs have been performed, this variable reflects the interval to the start date of the first PCI.
Nationally available from 2007 onward.
This variable refers to radiotherapy targeting the primary tumour.
Determination of pre- and post-surgical therapy is based on the chronological order of procedures in the NCR. The first surgical resection is used as the reference point. Local procedures (e.g. tumour destruction, excision biopsy, photodynamic therapy, electrocautery, cryosurgery, radiofrequency ablation) are not included.
Refers to radiotherapy targeting the primary tumour.
The incidence date is defined as the date of the first histological or cytological confirmation of the primary tumour
Available since 2010
Treatment data
rt_start_int[1-3]
Interval between incidence date and start date of radiotherapy (days)[1-3]
Refers to radiotherapy targeting the primary tumour.
The incidence date is defined as the date of the first histological or cytological confirmation of the primary tumour
Available since 2010
Describes for each radiotherapy treatment whether it is palliative, radical (with curative intent), or substandard (cannot be classified as palliative or radical according to existing guidelines). This concerns radiotherapy targeting the primary tumour. A combination of external beam radiotherapy and proton therapy is always considered radical. In addition, the (total) dose, the number of fractions, and the duration of the radiotherapy were taken into account. If the type cannot be determined based on this information, for example, because it is not (fully) recorded, the stage of the lung tumour is used instead; for stages 0, I, and II, radical treatment is assumed, and for stage IV, palliative radiotherapy.
Available since 2010. Until 2020, the number of fractions and the radiotherapy dose were not yet recorded in the NKR, so for earlier incidence years this variable is based only on the duration of the radiotherapy treatment and the tumour stage, and may therefore be less reliable.
Defined as the most extensive lung surgery performed with the aim of removing the primary tumour.
A carinal resection is considered the most extensive type of lung surgery, followed by pneumonectomy, bilobectomy, sleeve lobectomy, lobectomy, bisegmentectomy, segmentectomy, wedge resection, and lung surgery not otherwise specified.