Smoking & Pancreatic Cancer: What to Know About This Overlooked Risk

When most people think of smoking-related cancer, lung cancer first comes to mind — often followed by throat or mouth cancer. But pancreatic cancer? Not usually.

"Smoking is a well-established risk factor for pancreatic cancer, but public awareness of that link is low," says Dr. Mohammad Khalil, a medical oncologist at Houston Methodist.

With pancreatic cancer now the third-leading cause of cancer-related death in the U.S., understanding all of the risks — and how to reduce them — is critical to protect your health.

What does the pancreas do?

The pancreas is an organ located deep in the abdomen, tucked between the stomach and the spine. It performs two critical functions:

• Digestion: It produces digestive enzymes that flow into the small intestine to help break down food, known as the exocrine function
• Blood sugar control: It makes insulin and other hormones that regulate the levels of glucose in your blood, known as the endocrine function

The pancreas shares ducts with the bile system. This interconnection, along with its location tucked away behind other digestive organs, means pancreatic symptoms can be difficult to pinpoint.

What is pancreatic cancer, and how does it start?

Pancreatic cancer begins when cells in the pancreas grow out of control. The most common type is pancreatic adenocarcinoma, which begins in the cells lining the exocrine ducts that carry digestive enzymes.

"Pancreatic cancer typically doesn't cause any noticeable symptoms in the early stages," Dr. Khalil says. "One of the most common symptoms is jaundice, where the skin and eyes turn yellow. Jaundice without pain is one of the red flags."

In addition to jaundice, other symptoms of pancreatic cancer include:

• Unexplained abdominal pain or back pain
• Loss of appetite or unexplained weight loss
• Nausea or vomiting
• Light-colored stools or dark urine
• New-onset diabetes without weight gain

How is pancreatic cancer different from other cancers?

Unfortunately, pancreatic cancer has the worst prognosis among all major cancers. Currently, the overall five-year survival rate for cancer confined to the pancreas is 44%. The number drops to 13% when the cancer has already spread (all such stages combined).

"Part of what makes pancreatic cancer so deadly is that it doesn't cause obvious symptoms until it's progressed to a stage that's harder to treat," says Dr. Khalil. "It's also a very aggressive cancer. More than 80% of cases are diagnosed at an advanced stage."

How is smoking linked to pancreatic cancer?

Like many other types of cancer, smoking is a significant modifiable risk factor for pancreatic cancer. Decades of research show that smoking roughly doubles the risk of pancreatic cancer and is thought to contribute to about 20% of cases. When compared with non-smokers, smokers are two to three times more likely to develop pancreatic cancer.

The connection starts with the chemicals that make up cigarette smoke. Scientists have identified more than 7,000 different substances. At least 70 of these chemicals, known as carcinogens, are known to cause cancer.

"When the chemicals in cigarettes are inhaled, they find their way outside of the lungs," explains Dr. Khalil. "The carcinogens circulate in the blood and end up in different organs. The pancreas receives a high volume of blood, allowing the cancer agents to accumulate and start the damage."

If the toxic chemicals reach the pancreas, they can trigger genetic mutations in the DNA, leading to tumor formation. Cigarette smoke has also been shown to alter the body's immune environment, making treatment more difficult.

(Related: Tips on Quitting Smoking for Good)

Does the risk of pancreatic cancer decrease if someone quits smoking?

Yes — and the sooner, the better.

"Quitting smoking absolutely reduces the risk of pancreatic cancer," says Dr. Khalil. "We know the benefits begin right away, and the risk goes down significantly within about two to five years."

A recent study has shown that each year after quitting was associated with about a 9% reduction in the excess risk from prior smoking.

"After 10 to 15 years of being smoke-free, the risk drops to the level of someone who has never smoked," Dr. Khalil adds. "Every year without smoking lowers your risk."

(Related: 8 Ways to Reduce Your Cancer Risk)

What are other risk factors for pancreatic cancer?

While smoking is a major contributor to pancreatic cancer, it's not the only risk factor. Genetics and family history can also play a role.

"About 10% of cases are linked to specific inherited mutations," Dr. Khalil says. "People with multiple relatives who've had pancreatic, breast, ovarian, colon or prostate cancer should consider genetic counseling."

Related reading: Why Knowing Your Family Health History Matters

Other risks include:

• Age, gender and race: Most cases are diagnosed after age 60. Rates are slightly higher in men, and Black Americans face a higher incidence than white, Hispanic or Asian populations.
• Other health conditions: Patients with pancreatitis, a long-term inflammation of the pancreas, face a higher risk. So do people with diabetes. Obesity, measured as a body mass index of 30 or higher, is also linked — especially for those with central adiposity, more commonly referred to as belly fat.
• Lifestyle and food habits: Heavy alcohol use can lead to pancreatitis, a major risk factor. Studies show that a diet high in red and processed meats and low in fiber also can contribute.

(Related: How Excess Weight Affects the Body)

Are screening programs available for pancreatic cancer?

Unlike breast cancer, prostate cancer, colon cancer and lung cancer, there is no routine screening program for pancreatic cancer.

"Smoking alone is not considered a reason for screening," Dr. Khalil says. "But people with a family history or genetic risk may qualify."

Pancreatic cancer screening may be recommended for people with:

• Two or more close relatives with pancreatic cancer
• Known genetic syndromes (like BRCA2 or Lynch syndrome)
• Chronic pancreatitis
• Pancreatic cysts

(Related: Find Cancer Early: 5 Cancer Screenings You Should Know)

It's never too late to reduce your risk

While the statistics surrounding pancreatic cancer can be sobering, awareness is the first and most powerful tool. If you're concerned about risk, talk to your doctor — especially if you smoke and have a family history.

"Quitting smoking is the single most impactful way to reduce your risk," Dr. Khalil says. "Take note of unexplained symptoms like yellowing skin or unexplained weight loss, and make sure your doctor knows of any family history."