More than half of patients with metastatic lung cancer don’t receive life-extending treatments, like chemotherapy, immunotherapy and targeted therapy, a new study found. While the research couldn’t pinpoint why, experts suggest a constellation of barriers, including access issues, fatalism and shame.

The paper, published Thursday in JAMA Oncology, analyzed more than 250,000 people on Medicare between 2006 and 2021, with an average age of 73, and found that the proportion of patients who received these treatments increased only slightly over time, to 48 percent from 45 percent.

Lung cancer is the deadliest cancer in the United States, and more than 110,000 Americans are diagnosed with metastatic lung cancer annually. However, the outlook has changed significantly over the past 15 years, as dozens of promising new drugs have come to market, said Dr. Carolyn J. Presley, chief of thoracic medical oncology at Ohio State University who was not involved in the study.

For some patients, a pill can hold the disease in check for years, Dr. Presley said, “so the fact that so many older adults are not getting treatment is really, really sobering.”

Shame, access and other barriers to treatment

One of the biggest barriers to treatment is not being diagnosed in time. There are almost no pain receptors inside the lungs, so lung cancer often doesn’t cause symptoms until it’s metastasized. Screening can catch tumors early, but it remains widely underutilized, largely because most people don’t know it’s available and complicated eligibility criteria make it difficult for doctors to figure out who qualifies.

If someone receives a suspicious scan, they can lose even more time waiting for follow-up imaging, a biopsy and appointments, said Dr. Kyle Concannon, a thoracic medical oncologist at the University of Colorado Anschutz.

About 40 percent of patients in the new study died within three months of their lung cancer diagnosis. Many of them were probably just “too sick to get treatment by the time their tumors were found,” said Dr. Gerard Silvestri, a pulmonologist at the Medical University of South Carolina and the senior author of the study.

But that doesn’t fully explain why patients aren’t receiving treatment. The study also found that a third of patients with metastatic lung cancer never saw an oncologist. Even with health insurance, some of these patients probably struggled to afford or arrange transportation to a cancer center, or lacked the support to help them navigate their care, Dr. Silvestri said. The study found that rural residents and unmarried patients were less likely to be treated for metastatic lung cancer. Black and Hispanic people were also less likely to be treated.

Treatment decisions can also be shaped by fatalism — the lingering belief that metastatic lung cancer is hopeless, said Dr. Drew Moghanaki, chief of thoracic oncology at UCLA Health. Some primary care and emergency medicine doctors might see how far the cancer has spread and suggest that treatment is unlikely to help, he added.

In fall 2024, Maggie Rush was diagnosed with metastatic lung cancer. A local doctor had told her the disease had spread to her spine and abdomen, and she was trying to find an oncologist. But the pain had become so unbearable that she went to the emergency room in New Braunfels, Texas, for help.

Once there, the E.R. doctor pushed Mrs. Rush toward hospice care, her husband, Dave Rush, recalled. He seemed to assume that there was no point in treatment, Mr. Rush said.

So Mrs. Rush began to see treatment as futile, too. Bed-bound and ground down by the cancer, she felt that she would die within a few months, no matter what she did.

For many other patients, shame can be a factor in not seeking treatment, said Dr. Adam Fox, a pulmonologist at the Medical University of South Carolina who led the study. About 80 to 90 percent of lung cancers are tied to cigarettes, and experts say that patients who smoked might feel like they brought this disease upon themselves. Such stigma not only contributes to diagnostic delays, Dr. Fox added, but also to patients feeling unworthy of care.

The revolution in lung cancer treatments

Metastatic lung cancer means the disease is too widespread for surgery or radiation to eliminate. So for decades, the only real option was chemotherapy, which was highly toxic and typically gave patients only a few months more.

Many patients’ perceptions of lung cancer are still shaped by that era, Dr. Fox said. But the vast majority of people with metastatic lung cancer are now eligible for drugs tailored to the biology of their disease — like immunotherapy, which boosts the immune system to fight cancer, or targeted therapy, which blocks the specific mutation driving a person’s tumor.

Many patients who are too sick to receive chemotherapy can still take these new drugs, which are often gentler on the body, Dr. Moghanaki said. Moreover, these drugs typically yield results within a few weeks, he added, and can ideally keep cancer in remission for over a decade.

Although Mrs. Rush had lost hope, her son-in-law reached out to a relative, Dr. Concannon, who convinced her not to give up on treatment and got her an appointment with an oncologist.

Testing later showed that Mrs. Rush’s tumor carried a RET mutation, a genetic abnormality that made her eligible for a new lung cancer treatment. The drug didn’t cure her cancer, but her pain and fatigue eased. And Mrs. Rush was able to spend two more Christmases with her family and see her son marry.

Many people never get this chance.

More research is needed to know exactly why half of patients don’t receive life-extending treatment for metastatic lung cancer, said Dr. Nancy Keating, a professor of health care policy at Harvard Medical School. The new study only reviewed Medicare insurance claims and did not investigate the underlying reasons for the treatment gaps. Dr. Keating also noted that the study may have slightly overestimated how many patients went untreated, because insurance claims data can miss some oncology visits and medical care.

Experts say that every patient with metastatic lung cancer should have the opportunity to meet with an oncologist, since these specialists can guide patients and assess their tumors’ genetic weak spots.

It’s one thing if patients have a conversation and then choose not to be treated, Dr. Presley said. But it is far more troubling if they never see an oncologist at all. “We’re not even having a conversation with patients,” she added.