Cancer survivor: Learning I had Lynch syndrome ‘saved my life’
Dennis Massimo was only 42 and symptom-free when he was diagnosed with colorectal cancer, thanks to a research study he signed up for nearly a decade earlier.
Dennis Massimo doesn’t remember when he signed up for the Penn Medicine BioBank, but his sister Lauren Massimo, PhD, CRNP, does. It was 2016, Dennis, then 33, was getting his tonsils out, and Lauren encouraged him to consent to his blood sample being banked for future research.
Lauren, an associate professor of Nursing at Penn with an appointment in Neurology, where she co-directs the University of Pennsylvania Frontotemporal Degeneration Center, was used to being her family’s trusted health advocate. That decision may have saved his life.
Fast forward to April 2025.
Dennis, now 42 and working as a construction estimator, kept getting—and ignoring—calls from the BioBank. Having no memory of signing up for it nine years earlier, he assumed the calls were spam or a sales pitch. Finally, on April 14, he picked up the phone.
Dennis learned that a research project using samples from the BioBank found something called an MSH2 gene mutation in his DNA. As soon as he hung up the phone, he called Lauren. The siblings were already close, and this new medical information would only bring the family closer. Dennis and his wife, Carla, live essentially next door to Lauren and her husband, Kevin, in West Chester, PA, and their kids spend hours playing in the yard with their cousins.
Soon they learned that Dennis had Lynch syndrome, a condition that puts him at an increased risk for cancer. As if that wasn’t enough news, a tumor was already silently growing in his colon: stage III colorectal cancer that likely wouldn’t have been discovered and treated for years, had Dennis not followed his sister’s urging and signed up for the BioBank.
“I found out when the cancer was stage III and not stage IV,” he said. “It really could have saved my life.”
Lynch syndrome mutation leads to colorectal cancer diagnosis
When the BioBank called Dennis, they informed him that the first step was to confirm the finding. Because it came from a sample taken years ago for research purposes, a clinical diagnostic test was needed. The BioBank team introduced the Massimos to the Penn Medicine genetic counselor who would become their trusted guide and confidant for the journey ahead: Jessica Long, MS, CGC.
Long specializes in hereditary cancer predisposition syndromes—conditions that put individuals at much higher risk to develop specific cancers and often at earlier ages than the general population, due to inherited mutations. MSH2 is one of the genes that helps the body prevent cancer from developing, as part of what’s known as the DNA mismatch repair (MMR) system. When a mutation is present, the gene is unable to perform its normal role in cancer prevention, creating a greater chance for cancer to develop. Hereditary mutations affecting any one of four MMR genes, including MSH2, cause Lynch syndrome.
Lynch syndrome affects about 1.2 million Americans and is the most common cause of hereditary colorectal cancer. People with an MSH2 gene mutation have a lifetime risk of developing colorectal cancer ranging from about 30 to 50 percent, compared to less than 5 percent in the general population.
At 42, Dennis was still three years away from the recommended age for an average-risk person to begin getting screening colonoscopies. But due to his Lynch syndrome status, earlier screening was highly recommended.
A month after the BioBank phone call, Dennis went in for his first colonoscopy.
“The scariest part of the whole thing was waking up from the colonoscopy in a private recovery room, with a box of tissues next to me,” Dennis recalled. “I thought, ‘Oh my God, I’m in the grieving room.’”
Lauren was by his side to hear the news that a tumor had been found, and Dennis would need surgery to remove it.
“Dennis had zero symptoms, and he was only 42—colorectal cancer was not on his radar,” Lauren said. “We thought he would get a baseline colonoscopy. We didn’t think they would find a tumor.”
Leading-edge treatment at exactly the right time
Three weeks later, Dennis underwent a partial colectomy with Najjia N. Mahmoud, MD, chief of Colon and Rectal Surgery.
“From the first appointment, I felt like I was in the best hands possible,” Dennis said. “She was confident, clear, and incredibly reassuring. When you’re facing cancer surgery, that level of trust means everything.”
When he met with his oncologist, Ursina Teitelbaum, MD, after his surgery, the timing was extraordinary. Teitelbaum, who specializes in gastrointestinal cancers, had just returned from the annual meeting of the American Society of Clinical Oncology, where oncologists from across the world gather to report and learn about the latest advances in cancer treatment and research. One of the major studies reported at the meeting would directly impact Dennis’ treatment plan.
The Phase 3 ATOMIC clinical trial showed that adding an immunotherapy drug to standard chemotherapy for patients with stage III MMR-deficient colon cancer—Dennis’ exact diagnosis—significantly improved disease-free survival and halved the risk of recurrence and death versus chemotherapy alone.
In terms of receiving the latest, research-backed treatment recommendation, Lauren said, “you couldn’t be more up to date than that.”
‘A ripple effect’ for the entire family
Meanwhile, because Lynch syndrome is a hereditary condition that’s passed down from parents to children, Long was busy helping Lauren coordinate genetic testing for any other members of the Massimo family who wanted to assess their own risk.
“We got the clinical confirmation of Dennis’ MSH2 mutation at the same time as his colorectal cancer diagnosis, and it had a ripple effect for our entire family,” Lauren said. “It was unnerving, to say the least. Jessica became my closest ally during those months. Her expertise and empathy helped us navigate an overwhelming experience with confidence.”
This support—not only for the patient, but for their entire family—is part of what Long provides both as a genetic counselor and as the director of education and outreach for the King Center for Lynch Syndrome at Penn Medicine.
“Dennis’s story highlights the power of collaboration at Penn Medicine,” Long said. “From the BioBank research team to the care coordination among the genetics, surgery, oncology and gastroenterology teams, we aim to work together to support individuals managing a cancer diagnosis or a hereditary cancer syndrome, as well as their family members.”
Grateful for the warning
On Christmas morning of 2025, Dennis finished the chemotherapy portion of his treatment plan, giving the entire Massimo family a little something extra to celebrate. He’ll continue to receive immunotherapy infusions through August, close to home at Abramson Cancer Center West Chester, under the care of oncologist Zachary Quinn, MD.
Dennis is also staying ahead of his future cancer risk through a personalized cancer risk management plan developed by gastroenterologist Bryson Katona, MD, PhD, the co-founder and inaugural executive director of the King Center. Because Lynch syndrome causes varying levels of risk for different types of cancers, Katona oversees Dennis’ comprehensive Lynch syndrome care plan, setting a schedule for screening exams to make sure that any future cancers are detected early—or prevented altogether.
With two clean scans and ctDNA tests, which check for the presence of circulating tumor DNA in the blood, under his belt, Dennis feels relief and gratitude how quickly his cancer was treated after the serendipitous finding.
“I'm struck by the whole thing: Lynch syndrome, the BioBank, and the genetics,” Dennis said. “If a genetic test finding a DNA mutation could save me from getting stage IV cancer, how many other people could it save?”