Navy Veteran to Advocate: A Life-Changing Genetic Testing Journey

Dan "Dry Dock" Shockley served on multiple ships before he retired from his 22-year career in the United States Navy. That’s how he got his nickname, “Dry Dock,” traveling to 22 countries all over the world, docking in places like Singapore, Qatar, and Spain. But after settling into retirement on Oahu, he found himself on a new, unexpected journey.

In 2012, at age 51, Dan went in for his first colonoscopy, a routine screening for colorectal (colon) cancer involving a thin tube with a camera and light on the tip. A doctor inserts it into the rectum and through the colon to see if anything looks unusual. 

With no symptoms other than some unexplained weight loss and no known family history of cancer, the results came as a surprise. His doctor broke the news just after Dan woke from the procedure. 

“He told me he found over 100 polyps in my colon, rectum, and anus,” Dan said. “They were causing an 80% blockage in my ascending colon. I told him, Doc, what are you talking about? I feel fine. And he said that was the beauty of early detection."

Genetic testing for cancer risk leads to potentially life-saving treatment

Polyps are abnormal growths of tissue that can develop into cancer if left undetected and untreated. That’s why the American Cancer Society guidelines recommend that individuals at average risk of cancer start regular colorectal cancer screening at age 45.¹ If detected early, further tests can inform treatments to help prevent cancer from occurring. 

One of those tests is genetic testing. This type of test can reveal whether someone has a hereditary condition, meaning it’s passed down through their family. If they do have a positive result, it significantly increases their risk of developing colorectal cancer. With that information, their doctor can schedule them for more frequent screenings and preventive measures.

Dan’s doctor recommended he undergo genetic testing, and his results showed an APC gene variant that led to a diagnosis of attenuated familial adenomatous polyposis (AFAP). It’s a rare genetic condition that increases a person’s risk of developing cancer. 

After he received his results, Dan spoke to a licensed genetic counselor to help him understand what they mean and explain potential next steps. But even before that, he knew he wanted to take measures to remove the polyps. 

“I already knew in my mind that I wanted to have surgery,” he said. “I read that if you have a hereditary colon cancer syndrome, then any polyps left unattended really increase your chance of developing colon cancer.”

A short time later, Dan’s doctor performed surgery to remove his colon, rectum, and anus and create an opening in his stomach to dispose of waste into a bag, called a permanent colostomy.  Dan took it in stride, quickly embraced his condition, and adapted to life as an ostomate, as the community calls it. 

Always forge ahead with a purpose became his motto, a play on the shortened-form letters of his AFAP diagnosis. Dan said, “My certified genetic counselor and colorectal surgeon at Tripler Army Medical Center played a significant role in my ability to, as they say in the Marines, adapt, overcome, and improvise."

Years later, comprehensive genetic testing revealed a second rare gene variant in the LZTR1 gene. That led to Dan’s diagnosis of schwannomatosis, a long word that means he’s at risk of developing multiple tumors, called schwannomas, that form near nerve pathways. 

This double diagnosis made him a unique case in the medical world, and his healthcare journey, marked by two rare genetic conditions, uncovered a passion he carries with him today.

“If it wasn't for the genetic testing 13 years ago, I probably wouldn't be here now,” Dan said.

Colorectal cancer screening awareness becomes a newfound purpose

Driven to better understand and prepare for life with a hereditary colorectal cancer syndrome and an ostomy, Dan started on a research journey to learn as much as he could. But resources for people with hereditary cancers were and are limited, so he enrolled in the hereditary colon cancer registries at Creighton University, Johns Hopkins Hospital and the University of Michigan. These databases help researchers know more about the genetic causes of colorectal cancer and how to prevent, diagnose, and hopefully treat it.

Dan also found another purpose: raising awareness about AFAP, ostomy care, and the importance of early detection and screening in preventing colorectal cancer.