Residual cancer burden calculator

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Residual cancer burden (RCB) は，術前薬物療法施行後の切除標本の病理学的検索によって残存腫瘍量の程度を大まかに測定するもので，予後不良症例を予測するノモグラムとして米国MD Anderson Cancer CenterのSymmansらによって提唱された。

①原発腫瘍床の最大径 (d₁) と直行腫瘍径 (d₂)

②原発腫瘍床における浸潤癌の細胞密度 (finv)

③転移リンパ節個数 (LN)

④リンパ節転移の最大径 (dmet)

4項目について行い，以下の式で算出する。

dprim＝√￣￣d₁d₂RCB係数＝1.4×(finv dprim)0.17＋［4×(1－0.75LN)×dmet］0.17

＊　乳癌取扱い規約第19版2025年

Residual Cancer Burden Calculator

*Values must be entered into all fields for the calculation results to be accurate.

(1) Primary Tumor Bed

Primary Tumor Bed Area:

(mm) X

(mm)

Overall Cancer Cellularity (as percentage of area):

(%)

Percentage of Cancer That Is in situ Disease:

(%)

(2) Lymph Nodes

Number of Positive Lymph Nodes:

Diameter of Largest Metastasis:

(mm)

Residual Cancer Burden:

Residual Cancer Burden Class:

The following parameters are required from pathologic examination in order to calculate Residual Cancer Burden (RCB) after neoadjuvant treatment:

The largest two dimensions (mms) of the residual tumor bed in the breast (largest tumor bed if multicentric disease)

Submission of the entire largest cross-sectional area of the residual tumor bed for histologic mapping, with specific identification of those slides in the pathology report (e.g. "the largest cross-sectional area of primary tumor bed was submitted in cassettes A5 - A9")

If the residual tumor is large (i.e. largest diameter > 5 cm), then at least 5 representative cassettes from the largest cross-sectional area are sufficient, but should be identified in the original pathology report (e.g. "representative sections from the largest cross-sectional area of primary tumor bed were submitted in cassettes A5 - A9")

Histologic assessment of the percentage of the tumor bed area that contains carcinoma (all carcinoma, i.e. invasive and in situ), select one of the following:

0%, 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%

To assess cellularity it is helpful to scan across the sections of tumor bed and then estimate the average cellularity from the different microscopic fields.

When estimating percentage cancer cellularity in any microscopic field, compare the involved area with obvious standards, e.g. more or less than half, one quarter, one fifth, one tenth, one twentieth, etc.

Expect there to be variable cellularity within the cross section of any tumor bed, but estimate the overall cellularity from the average of the estimates in different microscopic fields of the tumor bed.

e.g. if cellularity in different fields of the tumor bed were estimated as 20%, 10%, 20%, 0%, 20%, 30%, then an average estimate of overall cellularity would be 20%.

Histologic estimate of the percentage of the carcinoma in the tumor bed that is in situ, select one of the following:

0%, 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%

The number of positive (metastatic) lymph nodes

The largest diameter (mm) of the largest nodal metastasis