Beginning in January 2018, oncology nurses will see changes to the way their patients’ cancers are staged with the American Joint Committee on Cancer (AJCC) system. According to a presentation at the National Comprehensive Cancer Network annual conference in March 2017, when the AJCC 8th Edition Cancer Staging System takes effect on January 1, 2018, more cases may be classified as stage I, especially for patients with breast cancer.
Shifting From Anatomic to Prognostic Staging
Since the 1940s, clinicians have used tumors (T), lymph nodes (N), and distant metastases (M) to determine a cancer’s anatomic stage. However, in recent years, new technologies such as genomic profiles and molecular targets have led to new classification called prognostic staging that builds a more complex picture of cancer on top of anatomic stage.
Edge said that prognostic markers like genetic testing explain why some patients with early-stage cancer have poor response to treatment whereas other patients with advanced cancer respond well to treatment. Prognostic staging incorporates these markers into cancer classification to provide a more tailored picture of each patient’s prognosis.
Additionally, Edge explained, the new AJCC prognostic staging system is a searchable and updateable database that will better aid researchers and clinicians in interpreting case data.
AJCC’s manuals have used factors other than T, N, and M in staging for some cancers in previous editions (e.g., prostate-specific antigen and Gleason score for prostate cancer staging), but the 2018 8th edition shows a marked increase. However, Edge said that not all cancer types have validated nonatomic factors that can be used for prognostic staging, so not every cancer will see changes in staging.
Implications for Breast Cancer Staging
One of the cancers that will see some of the largest changes under the new system is breast cancer. The new prognostic staging will require T, N, and M; grade; HER2; and estrogen- and progesterone-receptor status. When appropriate, it will also factor in genomic profiles (e.g., Oncotype DX, Mammaprint).
A breast cancer formerly classified as T2N0 or T1N1 HER2+ would now be considered stage I under the new system. In the past, any lymph node involvement would increase a cancer to stage II or higher, but Edge explained that most patients with T2N0 or T1N1 HER2+ breast cancers respond very well to treatment. Based on the staging revisions, more breast cancers in the United States will be classified as stage I disease and fewer as stage IIA, IIB, and IIIA in future years.
Lung cancer and head and neck cancers will also see major changes under the new staging system.
For more information, visit the AJCC website.