Descriptor |
What is described or measured |
How result is reported |
What the finding means |
Size |
Length and width of the tumor |
Largest dimension of the tumor, as measured in centimeters (1 inch = approximately 2.5 centimeters) |
Prognosis is likely to be better for smaller tumors; size is a primary factor in staging most cancers |
Noninvasive vs. invasive |
Whether cancer cells are confined to a single cell layer or spread to nearby (or underlying) tissue |
Noninvasive cancer is termed "in situ" |
Prognosis is likely to be better for noninvasive cancer |
Grade |
How closely the tumor cells resemble normal cells |
Grade 1: well-differentiated (cancer cells look mostly similar to normal cells)
Grade 2: moderately differentiated (some cancer cells look different than normal cells)
Grade 3: poorly differentiated (most cancer cells look different than normal cells)
Grade 4: undifferentiated (all cancer cells look different than normal cells)
|
The more the cancer cells look like normal cells, the better the prognosis; the higher the grade, the more aggressive the tumor |
Surgical margins |
Presence or absence of cancer cells in the normal tissue surrounding the tumor (known as the margin) |
Negative (or “not involved,” “clear” or “clean”): no cancer cells in the margin
Close: cancer cells are near the margin
Positive (or “involved”): cancer cells are in the margin
|
More surgery may be necessary if the margins are close or positive |
Lymphovascular invasion |
Presence or absence of cancer cells in the blood or lymph vessels |
“Absent,” “Present,” “Extensive” |
Cancer cells present or extensive in the blood or lymph vessels suggest a more aggressive tumor |
Lymph node status |
Presence or absence of cancer cells in the nearby lymph nodes |
Negative: no cancer cells
Positive: cancer cells
For breast cancer, the lymph node status is expressed as the number of positive nodes/total number of nodes removed and examined
|
Negative lymph node status is generally associated with less extensive cancer and a better prognosis; lymph node status is another primary factor in staging |
Proliferation rate (also known as Ki-67 proliferation index) |
Percentage of cancer cells that are actively dividing |
<10%: favorable prognosis
10-20%: borderline prognosis
>20%: unfavorable prognosis
|
This index is not always determined and may not be a factor in treatment planning, as it is not a consistently reliable measurement that correlates with stage |
Hormone receptor status (estrogen receptor [ER] and progesterone receptor [PR]) |
Expression of ER and PR on the cancer cells |
ER-/PR- (negative): receptors absent or present on few cancer cells (usually less than 1%)
ER+/PR+ (positive): receptors present on a high proportion of cancer cells
|
Positive tests for ER and/or PR indicate that the cancer is likely to respond to hormone therapy |
HER2 status (also known as HER2/neu, c-erb-B2 or erb-2) |
Presence of a protein produced by the HER2 gene on the surface of cancer cells (overexpression); or
Presence of extra copies of the gene (amplification)
|
When done by IHC (immunohistochemical analysis), 0 to +3, with 0, +1 and +2 being HER2- and +3 being HER2+
When done by FISH (fluorescent in situ hybridization), HER2- or HER2+
|
Presence of HER2 overexpression or amplification indicates a
fast-growing, aggressive tumor, but a HER2+ tumor is likely to respond to an anti-HER2 agent |