Reuters Health - Many women who follow initial breast cancer treatment with five years of hormone therapy to keep tumors at bay may still experience new malignancies up to two decades after their diagnosis, a study suggests. After treating ER-positive tumors with chemotherapy, radiation or surgery, women typically get five years of follow-up therapy in the form of daily hormone-based pills — either tamoxifen or aromatase inhibitors. The goal of such so-called adjuvant therapy is to destroy any lingering cancer cells not killed by initial treatment. All of the women were cancer-free when they completed five years of adjuvant hormone-based therapy. During the next 15 years, however, cancer returned for 41 percent of the highest-risk women in the study who originally had the largest tumors that had spread the most beyond the breast, the study found.
Should you be concerned about your cancer returning? Recurrence is cancer that comes back after treatment. This happens when some microscopic cancer cells survive treatment. Initially too small to be detected in follow-up tests, these cells eventually grow into new tumors. This is different than a new primary cancer, which is a tumor distinct from the original diagnosis. Most cancers that develop in the opposite breast are new primary cancers. A woman with a small non-invasive tumor with no lymph node involvement, for example, is less likely to have a recurrence than a woman with a large invasive tumor that has spread to her lymph nodes.
For some women, breast cancer may come back after treatment — sometimes years later. This is called a recurrence. Recurrence can be local in the same breast or in the surgery scar , regional in nearby lymph nodes , or in a distant area. Cancer that is found in the opposite breast without any cancer elsewhere in the body is not a recurrence—it is a new cancer that requires its own treatment. For women whose breast cancer has recurred locally, treatment depends on their initial treatment.
A breast cancer recurrence, or "recurrent breast cancer," is cancer that has come back in the same or opposite breast or chest wall after a period of time when the cancer couldn't be detected. During surgery to remove an original diagnosis of breast cancer lumpectomy or mastectomy , the surgeon removes all the cancer that can be seen and felt. But tests for cancer aren't sensitive enough to detect tiny groups of cancer cells that may be left over after surgery. It is possible for isolated groups of cells to survive radiation therapy and chemotherapy intended to reduce the risk of recurrence. Even a single cell that escaped treatment may be able to multiply and grow into a tumor.