4 December 2020

The actress Shannen Doherty revealed today that she has Stage 4 breast cancer. From media reports, it appears that she was initially diagnosed and treated in 2015 and developed a recurrence within the past year.

“Recurrence” simply means that the cancer has come back. Breast cancer can recur in the breast or chest area, which is called a local recurrence. This is usually treated with surgery to remove the recurrent tumor, most commonly mastectomy if lumpectomy was the original operation. Radiation therapy, chemotherapy, or hormonal therapy may also be recommended. The risk of local recurrence after lumpectomy is generally less than 10% and less than 5% after mastectomy.

Breast cancer cells can travel from the breast to the lymph nodes or through the blood stream and then deposit in other organs. This is termed systemic recurrence, metastatic breast cancer, or stage 4 breast cancer. The lungs, liver, bones and brain are the most common sites for metastatic breast cancer. Metastatic breast cancer is not curable, and patients who develop metastatic disease will require lifelong treatment.

Anyone who has been treated for breast cancer can develop metastatic disease. It is estimated that as many as 30% of patients will eventually develop metastatic disease but it difficult to get exact numbers because recurrences are not tracked like initial diagnoses are. The likelihood of developing metastatic disease is higher in patients who are diagnosed at more advanced stages and in those with more aggressive tumor biology / behavior, but even the less aggressive or slower growing tumors have the potential to spread. 

Since the most common sites of spread are the lungs, liver, bones and brain, attention should be paid to changes such as persistent cough or shortness of breath, abdominal pain, increased abdomen size, jaundice (yellowing of the eyes), persistent bone pain, fractures with no history of trauma, severe headaches, and new onset seizure. However, patients may have metastatic disease without any symptoms. While there is no true prevention, endocrine therapy (for those with estrogen receptor positive breast cancer) can reduce risk. A healthy diet, regular exercise, and weight control can also reduce risk. It is of course possible to do “everything right” and still develop metastatic cancer.

As mentioned, treatment for stage 4 breast cancer is lifelong. There have been many advances in the treatment of metastatic breast cancer – chemotherapy is not always required and newer targeted therapies have been developed. This is an area of active research. However, approximately 40,000 women and 500 men will die each year in the US due to metastatic breast cancer. More work is needed to better understand why some patients develop metastatic breast cancer, how to prevent breast cancer from spreading, and how best to treat it once it does spread.

Metastatic breast cancer information from cancer.net
Metastatic Breast Cancer Network
Metastatic Breast Cancer Alliance
Metavivor
MetUp