Table 1.
Criteria of Different Pathologic Systems for Evaluation of NAC Response
| Pathologic Criteria | Response Category | Brief Description | Reference |
|---|---|---|---|
| AJCC “y” classification | Pathological Complete Response (pCR) | Histopathological evaluation confirmed no invasive carcinoma in the breast and lymph nodes. Carcinoma in situ after treatment constitutes a pCR. | [74] |
| Clinical Partial Response (cPR) | Compared with clinical (pre-treatment) assignment, either the T or N category decreases or both the T and N categories decrease, while T or N does not increase, which indicates a partial response. Assessing the degree of clinical partial response (cPR) is best defined by comparing the pre-treatment clinical categories cT and cN with the clinical posttherapy categories (ycT and ycN). | ||
| No response (NR) | Compared with the clinical (pretreatment) assignment, no apparent change i4n either the T or N categories or increases in the T or N category at the time of y pathological evaluation, indicating no response to treatment. | ||
| NSABP B-18 | pCR | No recognized invasive breast cancer cells in the breast and lymph node. | [75] |
| pPR | The presence of scattered individual or small clusters of tumor cells in hyaline or desmoplastic stroma. | [58] | |
| pNR | Tumors do not exhibit the changes listed above. | ||
| Grade 1 (pNR) | No change or some alteration of individual malignant cells but no reduction in overall cellularity. | [59] | |
| Grade 2 (pPR) | A minor loss of tumor cells, but overall cellularity still high; up to 30% loss. | ||
| Grade 3 (pPR) | Between an estimated 30% and 90% reduction in tumor cells. | ||
| Grade 4 (almost pPR) | A marked disappearance of tumor cells such that only small clusters or widely dispersed individual cells remain; >90% loss of tumor cells. | ||
| Grade 5 (pPR) | No malignant cells identifiable in sections from the site of the tumor; only vascular fibroelastic stroma remains, often containing macrophages; DCIS may be present. | ||
| Chevallier Method | Class 1 (pCR) | Disappearance of all tumors both on macroscopic and microscopic assessment. | [76] |
| Class 2 (pCR) | In situ carcinoma present but no residual invasive tumor and negative lymph nodes. | ||
| Class 3 (pPR) | Invasive carcinoma present with stromal changes (sclerosis, fibrosis). | ||
| Class 4 (pNR) | Few or no modifications of the appearance of the tumor. | ||
| Sataloff category | Tumor-A (pCR) | Total or near total therapeutic effect (in the latter case, scattered cells account for >5% of the tumor surface). | [77] |
| Tumor-B (pPR) | Subjectively >50% therapeutic effect but less than total or near total. | ||
| Tumor-C (pPR) | >50% therapeutic effect. | ||
| Tumor-D (pNR) | No therapeutic effect evident. | ||
| Nodes-A (pCR) | Evidence of therapeutic effect, but no metastatic lesion | ||
| Nodes -B | No nodal metastasis or therapeutic effect. | ||
| Nodes -C | Evidence of therapeutic effect but nodal metastasis still present. | ||
| Nodes -D | Viable metastatic disease, no therapeutic effect. | ||
| RCB system | RCB 0 | No residual disease | [78] |
| RCB 1 | Minimal residual disease | ||
| RCB 2 | Moderate residual disease | ||
| RCB 3 | Extensive residual disease |