Breast Cancer Study Case

1

BREAST CANCER STUDY CASE

Scenario A

Carol Edwards, a 39 year-old premenopausal woman, had a screening mammogram which revealed an abnormality in the right breast. She had no palpable masses on breast exam. A mammographically localized surgical biopsy was done and revealed a small (0.9 cm) grade III infiltrating ductal carcinoma with some associated ductal carcinoma-in-situ (DCIS). The surgical margins were not clear (cancer cells were found at the posterior margin). Estrogen and progesterone receptors are negative.

The patient has been given the diagnosis in a telephone conversation with the surgeon a few days after the biopsy, and they are now meeting to discuss definitive treatment. Surgical treatment must address two issues: local control and staging.

LOCAL CONTROL can be achieved by mastectomy or by wide re-excision (known as "lumpectomy" or partial mastectomy) followed by radiation to the breast. The latter is known as breast conservation therapy (BCT) and it is imperative that margins be clear and cosmetic results acceptable to the patient to qualify for this option. In addition to this, there must be unifocal disease only, not multicentric cancers. If there are multiple foci of carcinoma, the patient should have a mastectomy.

Following healing, radiation to the remaining breast tissue is generally administered over a 6 week period (5 days/week). Side effects are minimal, consisting of fatigue and some local swelling and minor soreness of the breast with associated erythema (and occasionally sloughing of the epidermis which will heal). If chemotherapy is required, the radiation is scheduled to follow the completion of the chemotherapy; radiation and chemotherapy are not, as a rule, administered concomitantly. Radiation following total mastectomy is only recommended in select cases ? in patients with inflammatory breast cancer and in patients with locally advanced disease (as manifested by tumor size >5 cm and/ or with 4 or more positive nodes).

SURGICAL STAGING (to determine if there are regional metastases) is done by axillary lymph node dissection (ALND). There are no radiologic methods to reliably detect nodal metastases; microscopic confirmation must be achieved by removing some of the axillary nodes. Axillary node status is the single most important prognostic factor in determining breast cancer survival. Regardless of which local control option is desired, mastectomy or lumpectomy with radiation, ALND should be done. In this particular patient the information is especially important as it will determine whether or not adjuvant chemotherapy will be recommended. Because her hormone was hormone receptor-negative, the use of tamoxifen is not an option. For patients with tumors that have a favorable prognosis (as defined by size smaller than 1 cm and negative nodes) the potential benefits of adjuvant chemotherapy are probably outweighed by the risks. However, if nodes are positive, chemotherapy should improve survival.

The information in bold type below is from UpToDate:

2

INTRODUCTION -- The lymphatic drainage pathways of the breast (axillary, internal mammary [IM], and supraclavicular nodal groups) are the regional areas most likely to be involved with metastatic breast cancer.

RISK FACTORS FOR AXILLARY NODE INVOLVEMENT -- The axillary lymph nodes (ALNs) receive 85 percent of the lymphatic drainage from all quadrants of the breast; the remainder drains to the IM chain. The likelihood of ALN involvement is related to tumor size and location, histologic grade, and the presence of lymphatic invasion.

Tumor size and margins -- The likelihood of ALN involvement increases

as the size of the primary tumor increases. In one series of 2282 women

with invasive breast cancer or ductal carcinoma in situ (DCIS), the incidence

of ALN involvement was as follows:

?

Tis -- 0.8 percent

?

T1a -- 5 percent

?

T1b -- 16 percent

?

T1c -- 28 percent

?

T2 -- 47 percent

?

T3 -- 68 percent

?

T4 -- 86 percent

ALN metastases are relatively common even with invasive breast cancers 1 cm in size. In a second report of 919 such women who underwent ALN dissection (ALND); ALN metastases were detected in 16 and 19 percent of those with T1a (tumor size between 0.1 and 0.5 cm in greatest dimension) and T1b tumors (tumors between 0.5 and 1.0 cm), respectively. Many database series report a higher rate of ALN metastases for T1a than T1b disease. The higher rate in this group may be related to multifocal disease in DCIS, undersampling of the primary tumor, or high grade microinvasive carcinoma.

Nodal positivity rates are also higher in women who are found to have residual tumor after reexcision for positive margins following lumpectomy for breast conservation therapy (BCT). In one series, women with T1b tumors who had residual disease were significantly more likely to harbor ALN metastases than those whose tumors were either excised to a negative margin initially or who had negative reexcisions for an initially positive margin (36 versus 5 percent).

Histologic features -- Low grade (grade 1) tumors have a significantly lower rate of ALN metastases compared to grade 2 or 3 tumors. As an example, in data derived from the Surveillance, Epidemiology and End Results (SEER) database, the incidence of ALN disease in patients with grade 1 and grade 3 tumors of similar size was 3.4 and 21 percent, respectively. The presence of lymphatic invasion also increases the risk of ALN metastases.

3

Tumors that are associated with a less than 5 percent risk of ALN metastases include those with a single focus of microinvasion, ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download