RAMB Novembro/Dezembro 2015

azário

ACP

550

ssoc

ras

2015; 61(6):543-552

cGy/day) and a booster of 1000 cGy (fractionated at 200

cGy/day) in the tumor bed. When this treatment is not

performed, local recurrence is very high, approximately

30% (

versus

8% with radiation). Some protocols have been

prepared to assess the effectiveness of the intraoperative

radiation therapy, administered as a single dose. Although

the preliminary results are promising, there is no long

term follow-up data to determine the actual radiobiolog-

ical effectiveness and safety. Randomized studies and me-

ta-analyzes have shown that hypofractionated radiation,

i.e. higher doses applied at shorter time intervals, is a

safe and effective option for early breast cancer.

In tumors greater than 5 cm, or when more than four

lymph nodes are compromised, radiotherapy is also in-

dicated after a mastectomy, with the same purpose, which

is to prevent local recurrence. In this case, both the breast

and lymphatic drainage chains (internal thoracic and su-

praclavicular) are irradiated. In recent years, even when

axillary lymph node status is not high (one to three lymph

nodes), there is a tendency to indicate the same adjuvant

radiotherapy after mastectomy. Finally, radiation thera-

py may be indicated in bone metastases, particularly when

there is pain or risk of pathological fracture, and in brain

metastases.

The main prognostic factors for breast cancer include:

tumor size, axillary lymph node status, histological type,

histological grade, hormone receptors and c-

erbB2

Tumor size is directly related to prognosis and the

axillary involvement. Thus, the 5-year survival for cancers

smaller than 2 cm is 75%, and drops to 16% when the tu-

mor measures more than 7 cm. When the tumor mea-

sures less than 5 cm, axillary involvement occurs in 3% of

cases; 35% when the tumor is larger than 1.5 cm. Axillary

involvement plays an important prognostic role. When

there is involvement of 1 to 3 lymph nodes, the 10-year

survival is between 31 and 54%. When more than four

lymph nodes contain metastases, survival drops to 13%.

The most common histologic type of breast cancer

is the ductal or invasive of no special type (90% of cases),

followed by lobular (5-8%). In a small percentage of cas-

FIGURE 7

Sentinel lymph node. (A) Blue dye injection; (B) Sentinel lymph

node marked with blue dye; (C) Excision of sentinel lymph node marked with

blue dye.