Recently, the eighth edition of the TNM classification of AJCC (American Joint Commission of Cancer) was released. This had a few notable changes from the 7th edition, which have been highlighted below:
- Immunohistochemically detected tumor markers (ER, PR, HER 2 neu) that are known to have great practical treatment importance are now incorporated into the staging system to refine prognosis of breast cancer
- The eighth edition of the staging system also uses genomic assays (Oncotype Dx, Mammaprint, PAM 50) when available to downstage some estrogen receptor-positive, lymph node-negative tumors.
- Lobular carcinoma in situ is removed from the staging system because it is not a malignancy but a risk factor. It is no longer considered Tis.
- The expert panel clarified that the postneoadjuvant therapy pathological T category (ypT) is based on the largest focus of residual tumor, if present. Treatment-related fibrosis adjacent to residual invasive carcinoma is not included in the ypT maximum dimension.