Facts on File Encyclopedia of Health and Medicine

case with traditional staging, criteria vary some-
what among the different types of cancer.

GENERAL CANCER STAGING: TNM METHOD

Stage Extent of Cancer
Tumor (T)
T0 no evidence of cancer
Tis in situ; tumor confined to cells of origin
T1 localized tumor less than 3 centimeters (cm) in
size
T2 tumor is larger than 3 cm orhas invaded
adjacent tissues
T3 tumor is larger than 3 cm and has invaded
adjacent tissues
T4 large tumor has invaded adjacent tissues or is
inoperable
Lymph Nodes (N)
N0 no cancer in regional lymph nodes
N1 cancer in local lymph nodes
N2 cancer in regional lymph nodes
N3 cancer in lymph nodes beyond the region of the
primary tumor
Metastasis (M)
M0 cancer remains local or regional (no METASTASIS)
M1 cancer has spread to distant sites (metastasis)

Cancer Grading

The grade of a cancer identifies the characteristics
of its cells and their growth patterns. Grade is rele-
vant only for cancers that can have varying
aggressiveness, such as sarcomas and some types
of brain cancer. The pathologist determines the
tumor’s grade from tissue samples and assigns a
numeric value that indicates the tumor’s aggres-
siveness and likelihood for metastasis. As with
cancer staging, the criteria differ among the types
of cancer, though in general a higher grade value
indicates a more extensive or serious cancer. Some
tumors have a mix of different cancer cells, in
which case the pathologist usually assigns the
higher grade to the tumor overall.

Stage, Grade, and Outlook

Oncologists use cancer staging and grading as the

general framework for making treatment decisions

and assessing prognosis (expected outcome).

Though many types of cancer are treatable, con-

trollable, or curable with today’s range of treat-

ment options, the individual variation in cancer

diagnosis is significant. Each person who has can-

cer has a unique response based on numerous and

sometimes intangible factors. Staging, grading, and

other diagnostic parameters represent only a best

attempt to characterize a cancer so as to structure

an optimal treatment approach; they do not

define the outcome.

See also CANCER TREATMENT OPTIONS AND DECISIONS;

DIAGNOSING CANCER; LYMPH NODE; TUMOR MARKERS.

surgery for cancer An OPERATIONto remove a

cancerous tumor. Surgery is the first line of treat-

ment for cancer that a surgeon can readily reach

without endangering the person, and when there

is a single defined tumor. Multiple tumors may

also be appropriate for surgery, depending on the

type of cancer, the location of the tumors, and

how clearly contained the tumors are. Surgery is

typically the primary therapy for treating cancer,

with adjuvant (accompanying or follow-up) treat-

ment with RADIATION THERAPY, CHEMOTHERAPY,

IMMUNOTHERAPY, orHORMONE THERAPYfor a compre-

hensive approach. A person might undergo

chemotherapy or radiation therapy before surgery

to shrink the tumor, and also may undergo such

treatment after surgery to eradicate any remaining

cancer cells.

How Surgery Works to Treat Cancer

Surgery may be therapeutic (attempt to remove the

cancer) or palliative (remove enough of the tumor

to relieve PAINor other symptoms). As oncologic

surgeons have learned more about how cancer

grows and spreads in the body, surgery methods

surgery for cancer 393

GENERAL TUMOR GRADING

Grade Cancer Cell Characteristics Cancer Aggressiveness
G1 good differentiation, nearly normal cells low
G2 moderate differentiation, somewhat abnormal cells intermediate
G3 poor differentiation, abnormal cells high
G4 no differentiation, unstructured cells very high