HdBe-TNMTumorClassification

TNM Classification of Malignant Tumors (TNM) is the cancer staging system developed and is maintained by the Union for International Cancer Control (UICC). It is also used by the American Joint Committee on Cancer (AJCC) and the International Federation of Gynecology and Obstetrics (FIGO). In 1987, the UICC and AJCC staging systems were unified into the single TNM staging system. Nevertheless, there are still some differences between the two systems. The TNM-classification is developed for solid tumors. TNM is a notation system that describes the stage of a cancer, which originates from a solid tumor, using alphanumeric codes; T describes the size of the original (primary) tumor and whether it has invaded nearby tissue, N describes nearby (regional) lymph nodes that are involved, and M describes distant metastasis (spread of cancer from one part of the body to another). In addition to T, N and M, the classification also contains other parameters that may be relevant.

Purpose

TNM classification is a major determinant of appropriate treatment and prognosis. Stage is an increasingly important component of cancer surveillance and cancer control and an endpoint for the evaluation of the population-based screening and early detection efforts. The TNM staging system is the common language in which oncology health professionals can communicate on the cancer extent for individual patients as a basis for decision making on treatment management and individual prognosis but can also be used, to inform and evaluate treatment guidelines, national cancer planning and research. The objectives of the TNM classification are the following:

• Aid treatment planning,
• Provide an indication of prognosis based on historical outcome data,
• Assist in the evaluation of treatment results,
• Facilitate the exchange of information between treatment centers,
• Contribute to continuing investigations of human malignancies,
• Support cancer control activities, including through cancer registries.

The TNM classification is a unified standard. It goes beyond clinician practice and constitutes vital information for policy-makers developing or implementing cancer control and prevention plans.

Instructions

From a generic TNM Classification towards a disease-specific TNM Classification Development or implementation of a tumor-specific information model of the TNM Classification standard requires insight into how values sets can be restricted, expanded, and applied. Restriction of a value list means either leaving out items or making items more specific by choosing other terms within the official code system. The aim for the future is to have available ready-to-use value sets per type of malignancy. Codes systems This clinical model uses 2 international code systems:

• SNOMED CT (managed by SNOMED international, Dutch management by Nictiz)
• International Classification of Diseases for Oncology, version 3 (ICD-O-3), managed by the WHO.

For items where neither of these 2 code systems were considered useful or satisfactory, we chose to manage the value sets as part of the management of the HCIMs (Health and Care Information Models). When a unique and international reference to the TNM Classification standard as codesystem and the valuesets becomes availble these can be amended in a next version of the HCIM . Starting points from the perspective of the TNM Classification standard

• One TNM-classification per single organ, and one classification per side for paired organs. For example: when breast cancer involves a primary tumor in both breasts, there will be two instances of the HCIM with laterality ‘left’ for one breast and laterality ‘right’ for the other (‘bilateral’ is not allowed for paired organs).
• The HCIM does not only encompass the outcome of the TNM classification, but also the exact localization of the primary tumor(s), the positive lymph nodes, and metastases.
• In case of multiple primary tumors in the same organ, one should classify the tumor with the highest T-category, and mention the multiple presence or number of tumors between brackets. For example: T2 (m) or T2 (5). The lesion with the highest T-category determines the classification of the tumor. In order to distinguish between lesions and to represent each individual lesion, the HCIM has the container ‘Lesion’. Each lesion has a number. The HCIM does not represent which lesion (e.g. 1, 2, or 4) has the highest T-category, since this is only clear after judgment by the health professional on the basis of morphology and/or imaging.

Use of the ****UICC (http://www.uicc.org/resources/tnm) ****/ ****AJCC (http://cancerstaging.org/references-tools/deskreferences/Pages/default.aspx** )**** version of the TNM Classification of Malignant Tumours.**

• Although definitions and wording should not differ between the AJCC and UICC TNM classifications, some differences have regrettably crept in (for example: the definition of regional lymph nodes associated with carcinomas of the esophagus and endometrium). Therefore, the HCIM allows for choosing between the UICC or AJCC version. Criteria within the TNM-classification system have changed over the years and resulted in various editions. As a result, a specific tumor stage may have a completely different prognosis, depending on the edition used. Furthermore, it is important to consider the consequences of improved treatment over time.
• Beside staging based on the UICC or AJCC classifications there is the ‘Essential TNM’. This is a simplified version of the TNM, specifically developed for the representation of the occurrence of cancer in low wage countries. These countries often lack the resources for early diagnosis, and make limited use of the TNM classification system (in these countries, cancer is generally detected in a very late stage). This special version of the TNM has not been taken into account while developing this HCIM. Furthermore, the use of the ‘Essential TNM’ is generally limited to acquire data for statistics related to the prevalence of certain malignancies in these countries.

Prefix and suffix are integrated in value sets Although it would be possible to create separate value sets for the potential prefixes and suffixes associated with the T, N, and M items, we chose to facilitate the use of the model by integrating them in the T, N, and M value sets. This decision is based on the current insight that it prevents the creation of invalid combinations. **Prefix **

• **c: **Clinical classification, based on data prior to treatment, such as clinical examination, imaging, endoscopy, biopsies, surgical exploration or examination under anesthesia, and other types of examination.
• yc: Classification performed during or following initial multimodal therapy (non-surgical).
• p: Post-surgical histopathological classification. This is based on data prior to treatment, supplemented with pathological examination after surgical treatment.
• yp: Classification performed during or after multimodal treatment (including surgical treatment).
• rc: Clinical classification in case of a recurrent tumor (after a disease-free interval).
• rp: Postoperative pathological classificationin case of a recurrent tumor (after a disease-free interval).
• a: Classification determined during autopsy.

Suffix

• (mi): Cases with micrometastasis only
• (sn): Cases after sentinel lymph node assessment
• (f): Cases where FNA or a core biopsy is performed on regional lymph nodes
• (i-): negative morphological findings for isolated tumor cells (ITC)
• (i+): positive morphological findings for isolated tumor cells (ITC)
• (mol-): negative non-morphological findings for isolated tumor cells (ITC)
• (mol+): positive non-morphological findings for isolated tumor cells (ITC)
• (0): without elevated (LDH)
• (1): with elevated (LDH)

Patient Population

Adult patients with a solid tumor on which the TNM-classifications can be applied. Issues Usability of this HCIM as well as disease-specific code lists are created in the first pilot(s), planned in the summer of 2020. During these projects, IKNL will provide the maintenance for these code lists. When these pilot projects are completed, the findings will be included as change requests in the regular maintenance process of the HCIM center.