Table 2. Selected studies assessing the prognostic value of RCB.
| Study (year) | Ref. | Study design | Sample size and NACT regimens | BC subtypes | Biomarker | Prognostic value | ||
|---|---|---|---|---|---|---|---|---|
| Symmans et al. (2017) | [27] | Prospective cohort study | Total (n = 1,158) | All | RCB0 (pCR) vs. RCB1 vs. RCB2 vs. RCB3 | Combined T/FAC cohort: | ||
| - CT only: n = 955 | In combined T/FAC cohort: | TNBC: | ||||||
| - CT + H (H + T/FEC cohort): n = 203 | HER2+ (n = 103) | RFS (10-year): 86% vs. 81% vs. 55% vs. 23%, p < 0.01 | ||||||
| TNBC (n = 219) | HR-positive/HER2-negative: | |||||||
| HR+/HER2− (n = 501) | RFS (10-year): 83% vs. 97% vs. 74% vs. 52%, p < 0.01 | |||||||
| In H+T/FEC cohort: | H + T/FEC cohort: | |||||||
| HR+/HER2+ (n = 108) | RFS (10-year): 95% vs. 77% vs. 47% vs. 21%, p < 0.01 | |||||||
| HR−/HER2+ (n = 95) | Prognostic value were similar for both 5-year RFS and 5/10-year OS (RCB0/1 were significantly better than RCB2 or RCB3 in all treatment cohorts and breast cancer subtypes). | |||||||
| Campbell et al. (2017) | [32] | Prospective cohort study | Total (n = 162) | All | Continuous RCB score | TNBC: RFS: p < 0.0001 | ||
| - CT only | HR+/HER2−: RFS: p = 0.0053 | |||||||
| HER2+: RFS: p = 0.0091 | ||||||||
| Categorical RCB score | pCR vs. RCB1 vs. RCB2 vs. RCB3: | |||||||
| RFS (5-year): 86% vs. 85% vs. 75% vs. 41%, p < 0.0001 | ||||||||
| RCB 3 vs. RCB 0/1/2: | ||||||||
| Hazard ratio, 3.37; 95% CI, 1.96–5.80; p < 0.0001 | ||||||||
| Asano et al. (2017) | [29] | Retrospective analysis | Total (n = 177) | All | RCB-TILs-positive (RCB-I and positive for TILs) versus RCB-TILs-negative | RCB-TILs-positive is better for recurrence in all patients | ||
| - CT only | TNBC (n = 61) | DFS: 51% vs. 22%, hazard ratio, 0.048; 95% CI, 0.012–0.188; p < 0.001 | ||||||
| - CT + H | HER2+ (n = 36) | OS: 51% vs. 25%, p = 0.005 | ||||||
| HRBC (n = 80) | ||||||||
| Sharma et al. (2018) | [117] | Prospective cohorts study | Total (n = 183) | TNBC | RCB classes | RCB0 vs. RCB1: Similar 3-year RFS (90% vs. 93%) and 3-year OS (94% vs. 100%) | ||
| - CT only | RCB2 vs. RCB3: RCB2 better | |||||||
| RFS: hazard ratio, 4.70 (95% CI, 1.97–11.20), p < 0.0001 | ||||||||
| OS: hazard ratio, 4.34 (95% CI, 1.59–11.84), p = 0.002 | ||||||||
| RCB0/1 vs. RCB2/3: RCB0/1 better | ||||||||
| RFS (3-year): 91% vs. 59%, p < 0.0001 | ||||||||
| OS (3-year): 95% vs. 75%, p < 0.0001 | ||||||||
| Luen et al. (2019) | [30] | Prospective study | Total (n = 375) | TNBC with residual disease after NACT | RCB index | Increasing RCB index was significantly associated with worse RFS (p < 0.001) and worse OS (p < 0.001) | ||
| - CT only | RCB1 vs. RCB2 vs. RCB3 | RFS (3-year): 86% vs. 67% vs. 26%, p < 0.001 | ||||||
| Sheri et al. (2014) | [31] | Retrospective analysis | Total (n = 220) | All | Residual proliferative cancer burden (RPCB): | Tertile 1 vs. Tertile 3: | ||
| - CT only | Tertile 1 (score 0–2.8) vs. Tertile 2 (score 2.8–3.72) vs. Tertile 3 (score > 3.72) | RFS: 83% vs. 34% | ||||||
| OS: 93% vs. 46% | ||||||||
| RPCB was significantly more prognostic than either RCB or Ki-67 alone, p < 0.001 | ||||||||
| Addition of post-treatment grade and ER further improved the prediction of outcomes | ||||||||
| Romero et al. (2013) | [118] | Independent prospective cohort study | Total (n = 151) | All | RCB classes and RCB index | RCB0 vs. RCB1 vs. RCB2 vs. RCB3: | ||
| - CT only: n = 105 | OS(5-year): 100% vs. 86.7% vs. 86.7% vs. 54.7% | |||||||
| - CT + H: n = 46 | RFS(5-year): 78.1% vs. 66% vs. 77.5% vs. 32.2% | |||||||
| RCB3 vs. RCB0-2: RCB0-2 better | ||||||||
| OS: hazard ratio, 4.240, p < 0.0001 | ||||||||
| RFS: hazard ratio, 3.859, p < 0.0001 | ||||||||
RCB = residual cancer burden; NACT = neoadjuvant chemotherapy; BC = breast cancer; CT = chemotherapy; H = trastuzumab; T = taxanes; F = 5-fluorouracil; E = epirubicin; C = cyclophosphamide; A= adriamycin; HER2 = human epidermal growth factor receptor 2; TNBC = triple negative breast cancer; HR = hormone receptor; RFS = recurrence free survival; OS = overall survival; CI = confidence interval; HRBC = hormone receptor-positive breast cancer; TILs = tumor infiltrating lymphocytes; ER = estrogen receptor; PR = progesterone receptor.