Many tumors can be eliminated with surgery, chemotherapy, radiation, and other treatments. But once cancer spreads, or metastasizes, to other parts of the body, it becomes much harder to stop.
In this Q&A, medical oncologist Emily Feld talks about how metastatic cancer is diagnosed and treated at Memorial Sloan Kettering Cancer Center (MSK). Dr. Feld, who sees patients at MSKCommack on Long Island, specializes in treating patients with genitourinary cancers, including tumors of the prostate, bladder, kidneys, and testicl*s.
Metastatic cancer occurs when cancer cells spread from the organ where they started to a distant part of the body. Metastatic cancers are considered stage4.
Even after cancer has invaded another organ, it is still identified by the place where it developed. For example, prostate cancer that has spread to the bones is not the same as cancer that started in the bones, known as primary bone cancer (of which there are several types, including osteosarcoma and Ewing sarcoma). Prostate cancer that has metastasized to the bones is still treated like prostate cancer, where we use treatments that may include hormonal therapy, chemotherapy, and targeted therapy. Similarly, colon cancer that has spread to the liver is still colon cancer, not liver cancer, and is treated with colon cancer therapies.
2. How does cancer spread from one part of the body to another?
Metastasis or metastatic cancer occurs when cancer cells break off from the tumor where they originated, travel through the bloodstream or lymph vessels, and establish new tumors in another part of the body. Scientists at MSK are studying how and why this happens, with the goal of finding ways to prevent it.
The symptoms vary dramatically depending on the person, the type of cancer, and where it has spread. For example, cancer that has spread to the bones may cause pain. Cancer that has spread to the lung might cause a cough or shortness of breath. Metastatic cancer can also cause general symptoms like unexplained weight loss, severe fatigue, or night sweats.
Other times, patients may not report any symptoms, but we detect an abnormality on their blood work. For example, a patient with liver metastases might have elevated liver enzymes that are otherwise unexplained.
4. How is metastatic cancer diagnosed and treated at MSK?
Metastatic cancer is diagnosed with imaging (CT scans, MRIs, and/or PET scans) to determine the extent of disease and with a biopsy of a tumor so that a pathologist can identify the specific type of cancer.
There are many treatments for metastatic cancer. The treatment plan is determined by the type of cancer, where it has spread, and the patient’s other health issues.
Systemic therapy — which may be intravenous or oral treatment — is most commonly used for metastatic cancers. Examples of systemic therapy include chemotherapy, immunotherapy, and targeted therapy. Systemic therapy is particularly beneficial since it can address both visible and microscopic cancer throughout the body. Local therapies, such as radiation or surgery, can sometimes be used as well to target one, or a few, areas of cancer.
For many patients with metastatic cancer, MSK-IMPACT® plays a key role in diagnosis as well as in determining the best treatment options. This test is able to look for hundreds of cancer-causing mutations in a single tumor sample. By identifying these mutations, we may be able to find a treatment specifically targeting the patient’s particular cancer.
For example, if a patient with metastatic bladder cancer is found to have an FGFR2 or FGFR3 alteration on MSK-IMPACT, they are a candidate for the targeted drug erdafitinib (Balversa™), which specifically blocks FGFR, thereby inhibiting cancer cell growth.
We recommend MSK-IMPACT testing for most of our patients with metastatic cancer, so that we can get additional information about their tumors. In many cases, molecular testing can also help us match patients with an appropriate clinical trial. MSK-IMPACT may also help us determine the best treatment for patients in which we are unable to determine where a metastatic cancer started in the body — known as cancer of unknown primary (CUP).
Lymph nodes are one of the most common places for cancer to spread. The liver, lungs, and bones are also common sites of metastasis. Certain types of cancer are more likely to spread to certain organs. For example, prostate cancer has a tendency to spread to bones. Melanoma, the most dangerous type of skin cancer, frequently spreads to the brain and lungs.
6. For patients with metastatic cancer, what kinds of clinical trials does MSK offer?
At MSK, we’re fortunate to have many clinical trials available to patients. These trials may be testing a new surgical procedure, a different kind of radiation treatment, or a new drug or combination of drugs. Many of the treatments that are now considered standard for treating metastatic cancer began with clinical trials led by doctors at MSK. This includes many types of targeted therapies as well as immunotherapies.
Many of the clinical trials open at our main campus in Manhattan are also open at MSKCommack, where I see patients, as well as MSK’s other Regional Care Network sites on Long Island and in Westchester and New Jersey. This means that patients can participate in these trials without traveling into the city. There are some trials that are available exclusively at our main campus in Manhattan, but we’re continually opening more trials at our regional sites.
There are select stage4 cancers that are curable (for example, colon cancer with limited spread to the liver). However, most stage4 cancers are what we consider treatable but not necessarily curable.
Many of the treatments we use, including radiation therapy and chemotherapy, are palliative. This means that these therapies can shrink tumors, relieve the symptoms of the cancer, and prolong survival but cannot completely eliminate the cancer. For some patients, palliative therapies can keep cancer under control for years. Multiple drugs usually need to be given in sequence over time because resistance often develops.
That being said, with recent advances in cancer treatment, we are seeing an increasing number of patients who have exceptional, long-term responses to therapy, particularly with immunotherapy and targeted agents. More and more patients are living longer and with an improved quality of life because of these advances.
