Residual cancer burden index

Residual cancer burden index, abbreviated RCB, is an empirical predictor of outcome in breast cancer in the post-neoadjuvant therapy setting.

Definition

The RCB index is defined as:

$RCB=1.4\ (f_{inv}\ d_{prim})^{0.17}+\lbrack {\ 4\ (1-0.75^{LN})d_{met}}\rbrack ^{0.17}$

Where:

$f_{inv}={\text{portion of tumour bed that is viable invasive tumour}}$

$d_{prim}={\sqrt {d_{1}\ d_{2}}}$

${\text{LN}}={\text{number of lymph nodes with metastatic carcinoma}}$

$d_{met}={\text{diameter of the largest lymph node metastasis}}$

The inputs to $d_{prim}$ are:

$d_{1}={\text{first in-plane tumour dimension}}$

$d_{1}={\text{second in-plane tumour dimension}}$

Interpretation

The original paper stratified patients into three groups using two cut-points:

• Low risk (RCB-I): RCB > 0 and < 1.36.
• Intermediate risk (RCB-II): RCB > 1.36 and < 3.28.
• High risk (RCB-III): RCB > 3.28.

If one includes the group without any residual disease: there are four groups (RCB-0, RCB-I, RCB-II, RCB-III).

See also

• Neoadjuvant therapy.

External links

• Online calculator for RCB index (mdanderson.org).