NEWSWEEK: Let’s start with a definition. What is metastatic breast cancer? My understanding is that there are two kinds: metastatic cancer found at the time of the original diagnosis, which constitute about 10 percent of cases, and metastatic cancer diagnosed later (in a recurrence). Can you explain? Jo Anne Zujewski: Clinically, the most important distinction is whether the breast-cancer cells are confined to the breast and lymph nodes—this is sometimes referred to as early-stage breast cancer—or if they are in distant sites, such as the bone, liver, lungs. Patients who have breast-cancer cells in distant sites are said to have advanced breast cancer—whether or not the cancer was detected at the distant sites at first diagnosis—or later.
Cells from malignant tumors can spread to other parts of the body by breaking away from the original or primary tumor and entering the bloodstream or lymphatic system. The cells invade other organs and form new tumors that damage these organs. The spread of cancer is called metastasis. When breast-cancer cells spread, the cancer cells are often found in lymph nodes near the breast. Also, breast cancer can spread to almost any other part of the body. The most common are the bones, liver, lungs and brain. The new tumor has the same kind of abnormal cells and the same name as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast-cancer cells. The disease is metastatic breast cancer, not bone cancer. For that reason, it is treated as breast cancer, not bone cancer. Doctors call the new tumor “distant,” or metastatic, disease.
What percentage of women diagnosed with breast cancer have a recurrence after treatment? This depends upon the stage of diagnosis; breast cancer can reoccur years after the initial diagnosis. NCI data shows that 89 to 90 percent of women who have an initial diagnosis of breast cancer are alive without disease five years after a diagnosis. However, since breast cancer can reoccur later—sometimes decades later—I would estimate that in the long term, about 30 percent of women will have a recurrence. This is hard to estimate as our treatments keep getting better, so data we have from 20 years ago do not apply to women diagnosed today. I find the NCI SEER data on the trends in breast cancer [comparing 1975-2000 data] very interesting and encouraging. [Click here to view the data.]
Is recurrence more likely when malignant cells are found in lymph nodes? Yes. Tumor cells found in the lymph nodes are a negative prognostic factor, which would lead to a diagnosis of Stage II or III disease as opposed to Stage I. Even when the cancer seems to have been completely removed or destroyed, the disease sometimes returns because undetected cancer cells remained somewhere in the body after treatment. A doctor will monitor recovery and check for recurrence of the cancer.
What treatments are available for breast cancer that has spread to the bones? We consider treatment based on the cancer cells. It could be hormonal, chemo or biological—herceptin or lapatinib—depending on the tumor type and the woman’s symptoms. However, bisphosphonates, which are given for bone health, have been shown to decrease the risk of pain and fracture, so these are often given to women with cancer in the bones.
Is there any new research that is promising for women who have breast cancer in their bones? Yes. We are looking at ways to decrease spread to the bones using the bisphosphonates in early-stage breast cancer to see if these agents will prevent bone metastasis in the first place. There are also other agents targeting bone-specific metastases in development. Laboratory researchers are also looking for what it is in cancer cells that predisposes a cancer cell to go to the bones. We should learn even more about this in the coming years.
What can you say about survival prospects for a woman whose breast cancer has spread to her bones? Metastatic cancer carries a poorer prognosis, regardless of where it has spread. Survival rates for localized cancer are 98 percent while for distant cancer the five-year survival rate is 26 percent. Women with metastatic breast cancer who have “bone only” breast cancer tend to do better than women who have metastatic breast cancer in the liver, lungs or brain.
Mrs. Edwards, who is 57, has said that she used fertility treatments to become pregnant with her two youngest children when she was in her late 40s. Do we know of any connection between fertility treatments and breast cancer? If there is a connection, it is not strong. There are many risk factors for breast cancer, amongst them being reproductive and menstrual history. The older a woman is when she has her first child, the greater her chance of breast cancer. Women who had their first menstrual period before age 12 are at an increased risk of breast cancer. Women who went through menopause after age 55 are at an increased risk of breast cancer. Women who never had children are at an increased risk of breast cancer. Women who take menopausal hormone therapy with estrogen plus progestin after menopause also appear to have an increased risk of breast cancer.
More than 175,000 American women will be diagnosed with invasive breast cancer this year. This news about Mrs. Edwards will scare them. What can you say to reassure them? The estimate for 2007 is 178,480. We have excellent treatments that are getting better all the time. There has been dramatic improvement in the five-year disease-free survival from 1975 to 2000, and we are still making progress. Mortality is down. Most women who get treated for breast cancer will not have a recurrence.
