Adjuvant therapy for breast cancer: a brief overview of the NSABP experience and some thoughts on neoadjuvant chemotherapy

Treatment plans for black and white women with stage II node-positive breast cancer. The National Cancer Institute Black/White Cancer Survival Study experience

BACKGROUND

The National Cancer Institute Black/White Cancer Survival Study began patient accrual in 1985 and was designed to investigate factors that might contribute to the observed racial differences in survival for cancer of the breast, uterine corpus, colon, and bladder.

METHODS

To determine whether there were racial differences in treatment in a clinically homogeneous set of patients, 305 (25%) of the 1222 women in this study with Stage II node-positive (N+) breast cancer were evaluated.

RESULTS

Patient characteristics for blacks and whites were similar for age, metropolitan area of residence, tumor size, extent of nodal involvement, and steroid receptors. Differences in histologic findings, tumor grade, and nuclear atypia were observed. Blacks had a higher frequency of comorbid conditions, especially hypertension (P < 0.00001). Fewer blacks underwent breast-conserving surgery (P = 0.004). In a multivariate analysis, race was no longer a significant factor in the selection of primary treatment, but education and metropolitan area of residence remained significant. Blacks and whites received similar postoperative systemic therapy, with combination chemotherapy (cyclophosphamide, methotrexate, and 5-fluorouracil) and tamoxifen, the most common cytotoxic and endocrine therapies used.

CONCLUSIONS

The National Cancer Institute consensus statement concerning adjuvant therapy for breast cancer was published in the middle of the 2-year period that study cases were accrued, and treatment plans in this study generally agreed with consensus guidelines. Should survival differences in black and white patients with Stage II N+ disease in this study be found, they are unlikely to be attributable to differences in initial or postoperative treatment.

Breast cancer

Breast cancer will affect 1 out of 10 women in the United States and cause 27 deaths per 100,000 women per year. The etiology remains unknown, but the incidence correlates with genetic as well as environmental factors. Screening programs have been shown to prolong the survival by early detection compared with control populations but remain underutilized by physicians and patients. Breast disease can be evaluated by physical examination and mammography and a definitive diagnosis made by needle aspiration, needle biopsy, or excisional biopsy. This allows the patient to participate in the decision regarding mastectomy vs. conservative surgery plus radiation therapy. These two approaches have equivalent survival in selected patients. Patients with locally advanced, nonmetastatic disease benefit from a multidisciplinary approach using preoperative chemotherapy and postoperative radiation therapy. This approach has allowed less disfiguring surgery and improved survival. Preinvasive carcinoma is diagnosed more frequently with the increased use of screening mammography. Local therapy options include simple mastectomy, local excision plus radiation, or local excision alone. The natural history and results of therapy in preinvasive disease are evolving as more data are accumulated. Systemic adjuvant therapy is recommended for all node-positive patients and most node-negative patients with invasive cancer. The specific modality (hormonal or cytotoxic) varies with the subgroup involved. Treatment of metastatic disease to palliate symptoms and prolong survival includes the use of local therapies (surgery and radiation) and hormonal and cytotoxic agents. Most patients benefit, but cure has been unobtainable. Newer approaches utilizing high-dose chemotherapy and bone marrow support with growth factors or autologous transplantation are currently being explored.