Stomach Cancer: Is There an Inherited Risk?

Receiving a stomach cancer diagnosis can be scary. And as you work with your healthcare provider to develop a treatment plan and undergo more testing, you will learn more about the type of stomach cancer you have.

You’ll likely have lots of questions about things like medication, symptom management and survival rates. Another question you may have: Is stomach cancer hereditary?

Oncologist Suneel Kamath, MD, explains the genetic risk for stomach cancer and why it’s important to have first-degree relatives undergo genetic testing in some cases.

The genetic risk for stomach cancer

“The vast majority of stomach cancers aren’t hereditary,” shares Dr. Kamath.

But in some cases, the genetic makeup of a person may raise the chances of developing stomach cancer. The types of genetic conditions that can increase the risk of stomach cancer include:

• Hereditary diffuse gastric cancer syndrome (HDGC)
• Lynch syndrome
• Li-Fraumeni syndrome
• Peutz-Jeghers syndrome
• Familial adenomatous polyposis (FAP)
• Common variable immunodeficiency (CVID)

“The average age of onset for gastric cancer is usually late 60s and early 70s, whereas with these hereditary syndromes, many times, people are diagnosed in their 30s and 40s,” he adds.

Another distinction? Most stomach cancers that aren’t hereditary affect a specific portion of your stomach’s lining and form solid tumors that can be spotted during testing.

But Dr. Kamath says that with hereditary diffuse gastric cancer, cancer cells cause a widespread, “diffuse” invasion throughout your stomach’s lining. It can be harder to detect and typically doesn’t result in symptoms until the cancer has metastasized (spread).

“The other classic feature of hereditary gastric cancer is that it’s associated with lobular breast cancer, a less common form of breast cancer,” he explains. “There’s often this association between families that have both of these cancers.”

As for the other inherited cancer syndromes, like Lynch syndrome, numerous people in one family may have multiple cancers — one of them being stomach cancer.

“The presentation is similar to nonhereditary gastric cancer, where it’s localized to one part of the stomach, not the entire stomach,” says Dr. Kamath. “But what’s unique with those is that many times, the age of onset is a lot younger.”

Who to share your diagnosis with

Processing your stomach cancer diagnosis can be a daunting task. You may feel overwhelmed, devastated and unsure of how to move forward.

And if you have a hereditary form of stomach cancer, you’ll also need to share your diagnosis with your family — an emotional conversation on its own — and explain how it may impact their risk of stomach cancer.

If you’re concerned about how to approach the topic, Dr. Kamath says it’s best to keep it simple and straightforward.

“You can say something like, ‘I was diagnosed with this hereditary syndrome and my doctors are recommending that other relatives also be tested,’” he outlines. “And just leave it at that. Obviously, it’s going to spark a lot of questions, but those are questions that really need to happen between the family member and their physician based on their own results.”

And while most people won’t have a hereditary syndrome, he adds that it’s still important that family members keep their doctors informed about any changes to their family history.

“If you have a close relative who had gastric cancer, tell your doctors about it,” Dr. Kamath advises. “That can be helpful if in the future you develop symptoms like stomach pain, feeling full quickly, trouble swallowing or weight loss. Your doctor may be more likely to do more testing rather than treat it as a benign condition.”

Should your family get screened or tested?

If you’re diagnosed with a hereditary form of stomach cancer, it’s recommended that first-degree relatives (parents, siblings, children) undergo genetic testing. Testing can include bloodwork or a cheek swab to get a sample of your genes.

“We recommend testing to make sure that they don’t have the same mutation, and then, based on what their test results show, we recommend a different pattern of cancer screenings,” states Dr. Kamath. “It may involve doing more intensive screenings beyond the usual mammograms and colonoscopies.”

Bottom line?

While it’s uncommon, there is a small chance that your stomach cancer is genetic. If you’re in that situation, it becomes important to notify and encourage your first-degree relatives to speak with their healthcare providers and undergo genetic testing.

“It’s important to remember that most hereditary cancer syndromes increase the risk of multiple types of cancer, so if a close family member has stomach cancer with a hereditary cause, you may be at risk for colon, thyroid and many other cancers, in addition to stomach cancer,” says Dr. Kamath. “The only way we would find this out is through hereditary genetic testing.”