TNM Gets an Upgrade in Eighth Edition Staging Guidelines
Nearly a century ago, cancer staging was a simple categorization of disease as either local, regional, or distant. Then in the 1940s, a French surgeon developed the concept for a staging system that uses the size of the primary tumor (T), its lymphatic involvement (N), and the presence of metastases (M) to stage a patient’s cancer based on the anatomic extent of the disease at the time of diagnosis.
Staging serves many purposes (https://www.medscape.com/viewarticle/877834): it defines the prognosis, guides treatment, and allows for tabulation and analysis of patients with similar prognoses. The TNM staging system has become a universal staging system for solid tumors and remained largely unchanged for the last several decades. Until now.
In 2016, the American Joint Committee on Cancer (AJCC) published the eighth edition of its cancer staging guidelines, effective for any cancers diagnosed after January 1, 2018, and the new edition has changed the landscape of cancer staging as we’ve known it. Although anatomic staging has been the foundation for cancer staging, it is now becoming one of the biggest challenges to the TNM system. Anatomic staging neglects to include biologic data (https://doi.org/10.3322/caac.21388) about the cancer or the patient, therefore telling only part of the story.
Many clinicians assert that anatomic staging alone has become less clinically relevant today because research has expanded our understanding of the biologic basis of cancer. Nonanatomic prognostic indicators (e.g., HER2, ER/PR, HPV) in many cases more accurately predict outcomes and response (https://doi.org/10.1245/s10434-017-6024-y) to treatment than anatomic factors alone. For example, HPV-positive oropharynx cancers are more radiosensitive, have fewer genetic alterations, and occur in patients who are younger, with fewer comorbidities and better performance status than HPV-negative (https://www.researchgate.net/publication/272843196_HPV_in_oropharyngeal_cancer_The_basics_to_know_in_clinical_practice). Thus, the staging, prognosis, and treatment approach should be different. However, without including HPV information in staging, those differences are not reflected in anatomic staging. The new staging guidelines have incorporated nonanatomic prognostic indicators for multiple cancers, and several prognostic factors are now required to complete staging (https://cancerstaging.org/Pages/default.aspx).
The following case example illustrates the impact of nonanatomic prognostic factors (https://cancerstaging.org/CSE/Registrar/Documents/Stage%20Classifications%20c%20p%20yc%20yp.pdf) on staging with the eighth edition guidelines (http://eepurl.com/cjQfOD).
Lucy is a 65-year-old female with a right-sided breast mass. Her primary tumor is greater than 50 mm in dimension (T3), with no lymph node involvement (N0) or metastases (M0). Her anatomic staging makes her a stage IIB. The nonanatomic prognostic factors required to stage a patient with breast cancer include histologic grade (G), HER2, ER, and PR status. Lucy’s cancer is a G3, HER2-negative, ER-negative, and PR-negative tumor. With the addition of prognostic factors, Lucy’s stage increases in severity from IIB to IIIB.
In practice, clinicians know patients with negative prognostic indicators (HER2, ER, PR) tend to have poorer outcomes than those with positive prognostic indicators, which is now reflected in the staging with the new guidelines.
Knowledge of cancer-related standards and guidelines is important to providing comprehensive nursing care. Nurses should be aware of the changes and ensure patients receive appropriate education about their cancer and selected treatment.
More information about the staging guidelines and educational resources on the eighth edition changes is available online (http://cancerstaging.org/About/news/Pages/Implementation-of-AJCC-8th-Edition-Cancer-Staging-System.aspx).