As many as 1 in 3 cancer patients suffers from PTSD. The healthcare system is just beginning to identify who’s at risk and to help them cope.

Before 1994, cancer patients were specifically excluded from the psychiatric definition of post-traumatic stress disorder (PTSD). So few survived their treatments at the time, there was rarely a “post” to deal with.

Today, there are 14 million cancer survivors in the United States, and diagnostic criteria for PTSD have now expanded to include them.

That’s left doctors and psychologists trying to figure out how to help these survivors put cancer in the rearview mirror as they live out the rest of their lives.

PTSD was first identified in veterans of World War I and has gotten a lot of attention in recent years for dogging veterans returning from the wars in Afghanistan and Iraq.

However, the condition can affect anyone who has experienced a serious threat of violence or death.

Cancer patients, told they may die and often put through physically grueling treatments, are certainly at risk. But there’s much less data to document their struggles.

The best research on PTSD in adult cancer patients followed non-Hodgkin’s lymphoma patients for 10 years after their treatment ended. It found that more than one third had lasting symptoms of PTSD. Another 12 percent reported they once had symptoms, but those had since faded.

Research on post-traumatic stress among breast cancer survivors found that 14 percent reported symptoms 15 months after treatment.

Because the link between cancer and PTSD is relatively new, few cancer patients actually get an official diagnosis, but many have a range of symptoms.

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Post-traumatic stress disorder is characterized by the inability to relax for fear that a trauma will return, as well as the avoidance of things associated with the trauma, such as a certain part of town. It can also include reliving a traumatic event in nightmares and flashbacks.

Research on PTSD suggests that sufferers are at high risk of suicide.

One Seattle woman told Healthline that her mother took her own life after surviving cancer because she was convinced it would come back.

“She never got over the fact that, despite surviving, the cancer would come back and she couldn’t bear the pain. The first time she tried [to kill herself], she didn’t succeed. She had pneumonia, which made her a bit delusional, and she mistook it for the tumor coming back. When she succeeded, it was because she knew, 10 years after, the cancer would probably come back and she didn’t want to wait around,” she said.

There’s a difference between the normal stress of facing a cancer diagnosis and the inability to get on with life after the cancer is gone.

“There are expected reactions to a life-threatening illness. They include things like sadness, worry, trouble sleeping, feeling uncertain about what’s next, feeling loss of control,” said Dr. Wendy Baer, the director of psychiatric oncology at the Winship Cancer Institute at Emory University in Atlanta. “We think about mental health problems when emotional problems are so bad that they get in the way — if you can’t get out of bed to go to a doctor’s appointment, if your worry is so bad that you can’t think about anything else.”

“We’re talking about people who relive, re-experience the trauma and have physical and psychological symptoms associated with that,” added Dr. Patricia Ganz, an oncologist at Jonsson Comprehensive Cancer Center at the University of California, Los Angeles, who conducted the lymphoma research. “We’re talking about people who are just ruminating about what happened to them and can’t get over it.”

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Since the beginning of this year, cancer treatment centers have had a tougher road to travel to be accredited by the American College of Surgeons’ Commission on Cancer.

The treatment centers must now screen patients for “psychosocial distress,” a broad category that includes practical problems, like lack of transportation to treatments, as well as patients’ emotional well-being.

The screening helps cancer centers identify patients early on who may be particularly vulnerable to lasting mental scars. Risk factors for PTSD include the severity of the illness, but there are also other generalized risk factors, such as poverty, past trauma, and a history of mental illness.

Psychosocial risk factor screening is a crude instrument, but it opens the door to incorporating mental health into the larger quality-of-life issues that are a growing focus at cancer centers, said Rebecca Kirch, the director of quality of life and survivorship at the American Cancer Society.

“It’s quite squishy. It doesn’t get down to the nitty-gritty, but it is a toehold to give legitimacy to something that previously was considered softer science,” Kirch said.

Ganz admits that the doctors who provide physical care often don’t grapple well with the emotional responses patients have.

“We don’t do a good job in general in oncology of even assessing anxiety and depression. Oncologists might have a hard time figuring this out because they treat a lot of people, and most do just fine. Screening is the first step,” said Ganz, who participated in an Institute of Medicine panel that recommended the screening requirement.

There are good reasons for oncologists to be more attuned to their patients’ mental health. Doctors may inadvertently help create the trauma that later haunts their patients.

“Unlike with other diseases that are very serious, the big thing with cancer is that our treatments are so toxic that we contribute to how people do,” Ganz said.

The intensity of the treatment does appear to be a risk factor for PTSD symptoms among cancer patients, independent of how grim their prognosis is. Lymphoma patients who had bone marrow transplants were more likely to experience post-traumatic stress than those who didn’t.

A host of factors, in addition to the severity of disease, determine which patients receive marrow transplants, said Sophia Smith, Ph.D., MSW, a Duke University researcher who co-authored the lymphoma research with Ganz.

Patients with head and neck cancers are especially prone to endure emotional scars as a result of the unique challenges of treating those cancers. Patients must wear personalized masks that block radiation from healthy parts of the head while allowing it to pass through to cancerous areas. They are restrained for radiation treatment.

“The nature of the treatment leaves people with even less control,” Smith said.

How doctors relate to patients at the time of treatment also affects their risk of post-traumatic stress. Patients who have a good relationship with their medical team are less likely to experience symptoms of PTSD.

Patients who experience PTSD symptoms may be less able to participate in follow-up care. They may avoid doctors, hospitals, and lab tests, Smith said.

“Where this gets to be a problem is when a patient has so much trouble going to the hospital for follow-up appointments. One of our concerns is that, if a patient has PTSD, they might be less likely to return for follow-up care,” she said.

All told, when attention is paid to quality of life, patients don’t just live better, they live longer, according to Kirch.

“It’s not just politically correct, it’s scientifically correct to include this type of care,” she said.

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Cancer survivors often have a hard time moving on after cancer treatment because they are at high risk of seeing their cancer come back. For instance, a breast cancer survivor has a 1 in 5 chance of recurrence.

It’s so common for survivors to fixate on the possibility of a recurrence that the people who work with them have a name for the phenomenon: The Sword of Damocles. (In a Greek legend, a sword hung by a hair over the throne from which Damocles ruled.)

“It’s very normal to be worried about if this is going to come back. Every type of symptom that you feel thereafter you’re going to panic. You know, once you’ve been hit with a serious diagnosis, everything changes — some things for the better, and some things not at all,” Kirch said.

Many patients appear strong during treatment because they are busy with appointments, actively fighting the cancer. But when the treatments end, they find themselves waiting for the cancer to come back.

In other ways, too, cancer poses unique psychological challenges.

“One of the things is this psychological bit that it’s coming from inside of you — it’s actually in you,” Baer said.

Some patients and survivors feel betrayed by their bodies. And some survivors, although cancer-free, never really return to normal.

“I have some patients who don’t eat any more, they’re fed through tubes,” Baer said. “That’s a big challenge, to be dealing with this basic human drive.”

It’s important for cancer survivors to get mental health care that addresses their circumstances.

“You don’t want to be in a support group with people who were all in Iraq,” Baer said.

Although there are a growing number of cancer survivor support groups, not all major cancer centers provide mental health care. But Sophia Smith has an idea for a stopgap measure.

In 2011, the National Center for PTSD, part of the Department of Veterans Affairs, offered a free mobile app as a first line of support for vets. The app provides coping strategies to minimize the stress of PTSD. It also assesses symptoms and directs vets to available mental health support.

The National Center for PTSD has teamed up with Smith and others at Duke to create a version of the app tailored to cancer survivors. In an early test, 4 out of 5 users found the app helpful. It doesn’t treat persistent or severe symptoms of PTSD, but it can help survivors deal with their fears more productively.

Next month, the researchers will begin recruiting users for a larger scientific study of the app.

It’s just one sign of a growing awareness that war isn’t the only experience that leaves survivors shell-shocked, and physical survival alone doesn’t constitute a victory.