The use of neoadjuvant chemotherapy has been studied for many years. Clinical trials have compared giving chemotherapy before and after surgery and there has not been any increase in cure rate if the treatment is given before surgery. Hormonal therapy, or endocrine therapy, can also be given before surgery for breast cancers that are estrogen receptor positive – this is more commonly done in Europe than America, but it definitely has its indications.
There are two generally agreed upon reasons for giving chemotherapy (or hormonal therapy) prior to surgery in a patient with breast cancer.
(1) The cancer is quite large and would be technically difficult for the surgeon to resect, even with mastectomy.
(2) Some cancers might be amenable to a lumpectomy (preserving the breasts natural shape) if they were able to shrink before surgery. This is called “conversion” from mastectomy to lumpectomy and happens about 33 to 40 percent of the time with neoadjuvant chemotherapy.
There are some different aspects of chemotherapy before surgery. When chemotherapy is given after surgery – the traditional route – we refer it to as adjuvant chemotherapy, where the idea is that there might be some small pools of cancer cells that have left the breast and traveled (micrometastasis) which we want to eliminate – this is why adjuvant chemotherapy can increase the cure rate in breast cancer. With neoadjuvant chemotherapy this is part of the plan, but obviously we want to make a large breast cancer smaller as well.
To that end, we can tell right away if the chemotherapy is working – often the breast mass will get smaller after one or two treatments. And at the time of surgery, we can assess how much of the cancer is left – sometimes we don’t see much visible tumor (a complete pathologic response) and those patients have a higher chance of cure.
My practice is that if a patient is to have neoadjuvant chemotherapy that we give all treatments before surgery – studies have shown that the chance of cure depends on getting chemotherapy in full doses on time (e.g. every 2 or 3 weeks) – so I try to observe that with neoadjuvant therapy as well.