THE EARLIER YOU CATCH lung cancer, the better your chances are of curing the disease. However, when lung cancer cells spread to other organs (metastatic disease), the cancer usually becomes incurable.

How Lung Cancer Spreads

“Cancers like to do one of three things when spreading,” says Dr. Gaetane Michaud, an associate professor of pulmonary medicine and cardiothoracic surgery at NYU Langone’s Perlmutter Cancer Center. “They grow bigger in their location. They can get in their own lymphatic system, travel to a local, regional lymph node and go beyond to other lymph nodes in the body. And, tumors can also get into the vasculature and spread to other parts of the body via the bloodstream.”

Even when a lung cancer tumor spreads to another part of the lung, it’s still metastatic disease, Michaud says, because it gets there via the bloodstream instead of extending along the airways (growing bigger in its current location). “The usual pattern of spread is that the tumor gets bigger in its local site and then spreads into the lymph glands and then spreads into other parts of the body.” However, she says, it doesn’t necessarily follow that order. In a minority of cases, a patient might have a lesion in the lung and a discrete lesion somewhere else, with no lymph node involvement.

There’s also no pattern to how fast tumors grow and spread, Michaud says. “Tumors can do whatever they want. They can be slow growing, and then all of a sudden decide to accelerate fast. They can be fast growing from the start or be slow growing and stay slow growing. Or, they can even be fast growing early and then slow down.” You can’t predict what a tumor might do.

In newly diagnosed lung cancer patients, about a third have evidence that the disease has spread outside the chest around the body, says Dr. John Minna, a professor at UT Southwestern Medical Center. They will need to have chemotherapy or immunotherapy. “Another third have disease that appears limited to the lungs and potentially could be resected by a surgeon or treated with local radiotherapy,” he says. “The remaining third of patients have disease that is still localized to the chest but has spread to regional lymph nodes and will likely need some combination of chemotherapy, immunotherapy, surgery or radiation therapy.”

In contrast, Minna says, when you screen people who don’t have symptoms and find lung cancer early, 80 to 90 percent of the cases will appear to be confined to the lung. However, when you look for metastatic disease, in 10 to 20 percent of those patients, you’ll see the cancer has already spread.

Finding Metastatic Lung Cancer

Oncologists use CT scans and PET scans with radioactive tracer to find metastatic lung cancer, Minna says. A CT scan is the most sensitive test. By using a dye, a CT scan can differentiate between tumors and normal tissue. Oncologists usually use a CT scan first, Minna says, and, if they find something suspicious, they also do a PET scan. Tumors are metabolically active and use sugar for energy. These active areas absorb a lot of the radiotracer and light up on a scan, so they’re helpful for finding all but the smallest tumors (less than 1 centimeter).

PET scans are good for finding metastatic cancer in all areas of the body except the brain, which is always metabolically active, Michaud says. So, they’ll use an MRI to find brain lesions. A PET scan is also not 100 percent accurate. Infections and inflammation can appear as metabolically active areas. “We don’t call anything metastatic until we take a piece of it [a biopsy],” she says.

Where Lung Cancer Spreads

While lung cancer can go anywhere, it tends to favor five locations, Minna says: the liver, adrenal glands, bones, brain and lymph nodes, especially in the chest. Doctors don’t know why lung cancer cells spread to one area and not another. However, Minna says, when a lung cancer cell metastasizes to the brain, as opposed to the liver, it probably has something different in its biology that allows it to lodge there, survive and grow. He says we’re just beginning to understand these molecular differences. “It may be that hundreds of [cancer] cells went to the brain, but perhaps only one ‘took.’ What was the difference? It we knew, we could block that difference, so even if a cell went to the brain, it couldn’t grow there.”

Treating Metastasized Lung Cancer

When patients have lung cancer that has spread, oncologists treat the metastasized cancer first, especially if it’s in the brain. If a patient only has one small lesion outside of the lungs, a surgeon will try to remove it. Minna says stereotactic radiation, which uses high doses of very focused radiation, is useful in treating brain (and some other) metastases because it requires only a few treatments and doesn’t cause many side effects. This can help spare the brain from damage. However, if the cancer has spread to multiple locations, it’s usually not possible to remove the tumors surgically. In these cases, Michaud says, she treats patients’ metastatic disease with systemic therapy, such as chemotherapy or immune therapy. “These treatments extend life and improve quality of life.”

For patients with metastatic cancer, palliative care, also called comfort care, is important. “Palliative care has a huge impact on patient outcomes,” Michaud says. “It helps people with symptom management. Early intervention with palliation is really important.” For example, Michaud might remove tumors from patients’ airways to help them breathe better or install a drain to ease discomfort for patients who have fluid around their lungs.

ichaud says recent innovations in lung cancer treatments are extending duration of life for patients with metastatic lung cancer. She says oncologists are profiling tumors and finding out what targets they have in order to use the body’s own immune system or targeted therapies to kill off cancer cells.

Best Hospitals for Cancer

#1University of Texas MD Anderson Cancer CenterHouston, TX
#2Memorial Sloan Kettering Cancer CenterNew York, NY
#3Mayo ClinicRochester, MN
#4Dana-Farber/Brigham and Women’s Cancer CenterBoston, MA
#5Seattle Cancer Alliance/University of Washington Medical CenterSeattle, WA
#6Johns Hopkins HospitalBaltimore, MD
#7Penn Presbyterian Medical CenterPhiladelphia, PA
#7Cleveland ClinicCleveland, OH
#9Moffitt Cancer Center and Research InstituteTampa, FL
#10UCSF Medical CenterSan Francisco, CA

Hospital Ranking information as of October 12th, 2017

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