The majority of systemic treatment in this disease is given in the 'adjuvant' setting, treating micrometastatic disease at the time of diagnosis to completely eradicate it and prevent subsequent systemic recurrence and death. The most commonly cited rationale for adjuvant treatment is given in the series of papers written by the Early Breast Cancer Trialists Collaborative Group. There was clearly a survival and relapse-free survival benefit to those patients with both node negative and node positive breast cancer who received chemotherapy. The benefits, however, are only in the range of 5 to 15 percent survival benefit at ten years in those women who received treatment compared to those who did not receive post surgical, systemic treatment. Several recent publications have presented practice guidelines.
Oncologists continue to debate the relative merits of various regimes of chemotherapy.
The long-term toxicity of the anthracycline are currently unknown, but remain a concern. The relationship between breast cancer and pregnancy remains unclear. Breast cancer is the most common malignancy in pregnant women, occurring in three of every 10,000 pregnancies. Early first pregnancy and multiparity are known to decrease the risk of subsequent breast cancers. The effect of pregnancy termination on subsequent breast cancer risk remains unclear but probably has a minor, if any, effect.