Adenocarcinomas: 6 things to know about the ‘cancer of the cavities’

Adenocarcinomas can develop in many different parts of the body, including the lungs, prostate, colon, rectum, small bowel, pancreas, stomach, esophagus, uterus, parotid gland, cervix (very rarely) and even the appendix.

But what qualities define them as adenocarcinomas? And are there any symptoms or other features that are common to all adenocarcinomas?

We checked in with Jaffer Ajani, M.D., a medical oncologist who specializes in gastrointestinal cancers.

What makes a cancer an adenocarcinoma?

Human embryos have two major types of initial tissues that develop into the various components of our bodies.

• Ectodermic tissue becomes skin, muscles, bones, joints, and connective tissues, such as tendons, ligaments and cartilage.
• Endodermic tissue forms many organs, such as the pancreas, prostate, and digestive tract.

Endodermic tissue also forms the lining of many internal surfaces of the body, including hollow organs and cavities, such as the stomach and colon. Adenocarcinomas can develop anywhere there is endodermic tissue.

How do adenocarcinomas develop?

When we’re very young, we have pretty much the same genes in almost every cell. These are the genes that we’re born with, which we inherited from our parents: half from mom and half from dad.

But as we grow older, two major factors affect the integrity of those genes. One is our lifestyle  – what we eat, whether we use alcohol or tobacco, and how much we exercise.

The second factor is our environment – what chemicals we’re exposed to in the products we use, the air we breathe, the water we drink, and the things we eat, whether it’s pesticides on crops, hormones in fish or livestock, or preservatives in processed meat. This applies to any UV radiation exposure we might get from sunlight or other sources, too.

Over time, all of these factors can damage our genes enough that they can’t repair themselves. When that happens, cancer may result.

Adenocarcinomas develop in different locations because different genes are involved. Our DNA is the same, no matter where it’s located. But it’s “folded” differently in various tissues, to allow access to certain genes. We have about 22,000 genes in all, but a pancreas doesn’t need all 22,000 to be a pancreas. It only needs maybe 500. So, the DNA strands are folded in such a way that those genes are more easily accessible. And those are the ones that get damaged.

How is adenocarcinoma usually diagnosed?

Normally, genes are very strong and capable of repairing themselves. So, external forces have to be pretty significant to cause lasting damage. That’s why it usually takes so long to achieve, and why cancer is diagnosed in older people more often than younger ones.

Unfortunately, many adenocarcinomas are often diagnosed in the late stages. That’s because several of the places in which they grow are tucked away deep inside our bodies.

With something like skin cancer, problems can become obvious pretty quickly. If there’s a spot on your hand that’s turning colors and bleeding, you’re going to notice it and get it taken care of right away.

But because many adenocarcinomas develop where we can’t see them, you could have one growing for years and not know it — until it becomes big enough to cause a problem, like blocking an intestine. That’s why screenings for diseases like colon cancer and endometrial cancer are so important.

How do symptoms of adenocarcinoma typically appear?

All adenocarcinomas are not the same. So, symptoms vary, depending on where a cancer is located.

With lung cancer, for instance, you might have a nagging cough or chest pain. With colorectal cancer, you might see blood in your stool. With cervical cancer, you might feel pain during sex. Here are some of the symptoms you might see with a few of the most common adenocarcinomas:

• Lung: nagging cough, chest pain, wheezing, rust-colored phlegm
• Colorectal: persistent diarrhea or constipation, blood in stool, rectal bleeding
• Prostate: trouble emptying bladder, painful urination, blood in urine, erectile dysfunction
• Pancreas: jaundice, dark urine, light-colored stools, bloating
• Esophagus: difficulty swallowing, heartburn, regurgitation, persistent hiccups

But any time you experience severe fatigue, unexplained weight loss, or significant changes in your appetite for more than a few weeks, you should get checked out by a doctor. All of those can be symptoms of a number of different types of cancer, not just adenocarcinoma.

How is adenocarcinoma usually treated?

Again, that depends on several factors – what type of cancer it is, where it is located, and how advanced it is.

That being said, chemotherapy is still used to treat many types of adenocarcinoma. But the particular drugs that are used to treat, say, an adenocarcinoma of the pancreas may be very different from those used to treat an adenocarcinoma of the lung or the stomach.

When cancer drugs were first discovered, doctors tried them out against every type of cancer. But as more drugs became available, it became clear that certain drugs only worked against certain cancers.

What are the latest advances in the diagnosis and treatment of adenocarcinoma?

Liquid biopsies are a fantastic advance in early detection.

When cancer cells die, they literally “spill their guts” into the bloodstream. Some produce particular proteins and enzymes while they’re alive, too. And we have blood tests now that can detect some of those materials, so we can find tumors earlier.

Cancer is easiest to treat when it’s caught early, so this is a great invention. I think all of us will be getting some type of blood test like this eventually, perhaps as part of an annual screening.

On the treatment side, I think immunotherapy and targeted therapy will eventually take over, and make chemotherapy a thing of the past.

That’s because chemotherapy is just chemicals that interfere with cellular processes, like metabolism, self-repair or division. But cellular therapies — such as CAR T cell therapy, vaccines, and immune checkpoint inhibitors — are a manipulation of the immune system itself.

When you use chemotherapy, it’s not smart enough to attack just the cancer. It attacks any machinery in any cell that it’s specific for. So, it can have a lot of side effects, such as nausea and diarrhea.

But our immune system is the most powerful drug there is against cancer. And now that we’re starting to understand cancer’s cellular machinery better, we’re developing different drugs that target specific drivers in lung cancer, colorectal cancer, pancreatic cancer, and so on. So, I expect future adenocarcinoma treatments to be very personalized and immunotherapy to be involved.

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