The primary considerations when assigning American Joint Committee on Cancer (AJCC) staging classifications is timeframe and criteria. The clinical staging (or classification) timeframe includes information obtained from the time of diagnosis throughout the diagnostic workup and ends at the initiation of definitive treatment. Within the clinical staging timeframe, criteria include physical exam, imaging, endoscopies, and diagnostic biopsies. It is important to emphasize that the mere existence of a pathology report that includes microscopic assessment does not exclude it from the clinical staging criteria. If the assessment was a part of the diagnostic workup, it has occurred within the clinical timeframe and can be used for clinical staging.
The pathologic staging/classification timeframe includes information obtained from the moment of diagnosis and throughout the diagnostic workup (i.e., all information from clinical classification), the operative findings and pathology report from the definitive surgery. Within the pathologic staging timeframe, criteria include all of the clinical staging criteria, operative findings from the surgeon, and the pathology report for the resected specimen. Observations from the surgeon in the operative findings that are not accompanied by a biopsy are included in the pathologic staging criteria (e.g., observation of extension without a tissue sample for pathologic review). Similarly, involvement found on imaging is considered in the pathologic staging criteria even in the absence of tissue biopsy.
According to the AJCC manual and trainings, the appropriate T, N, and M categories should be assigned based on the above AJCC rules. This may entail allowing, e.g., the pathologic staging M category to be properly assigned as cM1. However, cancer registry abstracting software is currently set up to code two separate and mutually exclusive clinical and pathologic strings of T, N, M, and stage categories, with an implied "c" in the clinical TNM string, and an implied "p" in the pathologic TNM string. Upon abstraction, the registrar has no way of recording the appropriate M category for the pathologic stage if it is cM1. This discrepancy between registry software data items and AJCC staging classification rules causes a dilemma for registrars when abstracting the T, N, and M data items and results in inconsistent coding practices and data loss.
As a result, this issue will be addressed upon implementation of NAACCR version 16-compliant software with the addition of new AJCC T, N, and M categories for the AJCC T, N, and M data items [940, 950, 960, 880, 890, and 900]. The new categories have been generated by adding the prefixes of 'c' and 'p' to existing valid clinical and pathologic T, N, and M categories respectively, and by modifying, adding, and deleting specific existing categories newly prefixed with a 'c' or 'p'. For example, the addition of pTis to the clinical classification T category will enable its use for in situ patients in accordance with the AJCC rules (serves as a reminder that the in situ diagnosis cannot be made on imaging alone). FORDS Revised for 2016, due to be released later this month, will include listings of valid categories and instructions for coding.
The Commission on Cancer (CoC) will require CoC-accredited cancer programs to use the new T, N, and M categories and convert historical data upon upgrading to NAACCR version 16-compliant software (Please see the NAACCR 2016 Implementation Guidelines for complete details). The new category options will be implemented for cases of all diagnosis years abstracted using NAACCR version 16-compliant software. Conversion of historical data for the diagnosis years of 2015 and earlier is being carried out for the purposes of formatting the data to accommodate consistent viewing, abstraction, and editing of the data across all diagnosis years. Please note that the prefixes included in the new categories are only intended to reflect clinical significance for cases diagnosed January 1, 2016 and later, and should not be analyzed in any fashion for cases diagnosed earlier.
This implementation will allow registrars to comply with AJCC rules while abstracting, thus reducing stage assignment confusion and increasing registrar confidence in assigning AJCC stage, increasing data integrity, and reducing the time and resources registrars and AJCC and CoC staff currently spend addressing these issues. The CoC would like to whole-heartedly thank registrars for their persistence in reporting this issue to AJCC and National Cancer Data Base (NCDB) and in pursuing answers to your questions.
The AJCC supports the new AJCC T, N, and M category options for the data items within cancer registry software. AJCC has updated the "Explaining Blanks and X" presentation, and added a new presentation "AJCC T, N, and M Category Options for Registry Data Items in 2016." These are available on the AJCC website under the Cancer Staging Education – Registrar – Presentations tab. In addition registrars are encouraged to review the AJCC Curriculum for Registrars, which provides further details about the new categories as well as comprehensive instruction on AJCC staging.