A report published by Biller et al in Cancer Prevention Research provides new details about a recently discovered condition in which childhood cancer survivors develop numerous colorectal polyps, despite not having a hereditary susceptibility to the condition.

The condition—known as therapy-associated polyposis—was first described by scientists from Dana-Farber Cancer Institute in 2014 based on a group of five patients. The new study presents a deeper look at the condition based on data from 34 patients at eight cancer centers around the United States.

More on Polyposis

The development of colorectal polyps in any individual is a risk factor for colorectal cancer. Polyposis, a condition in which many polyps grow in the intestinal tract, often signals a predisposition to colorectal cancer and other malignancies. People diagnosed with polyposis, as well as their relatives, are typically advised to undergo increased screening and other invasive procedures to detect the abnormal growths at the earliest stage possible. By knowing the specific signs of therapy-associated polyposis—and knowing that it isn’t part of a familial syndrome—physicians can spare family members unnecessary screenings and ensure patients receive proper treatment.

Leah Biller, MD

“Survivors of cancer in childhood or young adulthood have an increased risk for a variety of cancers and noncancerous conditions, including colorectal cancers and polyps, in the years after treatment,” said first study author Leah Biller, MD, a physician-researcher at Dana-Farber. “When they develop polyposis, we often are concerned about a hereditary cause and recommend testing to see if they have an inherited link to the condition. [Patients with therapy-associated polyposis], however, develop polyposis without a known hereditary susceptibility. This suggested that while their condition mimicked the symptoms of hereditary polyposis syndromes, it was a separate phenomenon.”

Findings on Therapy-Associated Polyposis

To determine the characteristics of therapy-associated polyposis, and potentially distinguish it from hereditary polyposis, researchers used data from numerous patients with the condition. The team gathered information on 34 patients with therapy-associated polyposis who did not have a hereditary or known genetic link to the condition but had been treated with chemotherapy and/or radiation therapy for childhood cancers. 

Patients with therapy-associated polyposis developed it a median of 27 years after their cancer treatment. Investigators also found that 35% of the patients had more than 50 colorectal polyps, and 94% had multiple types of polyps, including adenomas, serrated polyps, hyperplastic polyps, and hamartomas. This contrasts with other hereditary polyposis syndromes, in which all the polyps are generally of the same type.

Investigators also found that 74% of the patients had experienced other complications associated with cancer treatment: 50% had been diagnosed with cancerous conditions outside the colon and 47% had been diagnosed with noncancerous conditions indicative of prior cancer treatment. These findings suggest that people who develop therapy-associated polyposis may be especially susceptible to treatment-related conditions in general, the study authors explained.

“Therapy-associated polyposis appears to be an acquired condition that imitates various familial colorectal cancer syndromes but is biologically distinct from them,” said senior study author Matthew Yurgelun, MD, an oncologist specializing in gastrointestinal cancer and Director of the Lynch Syndrome Center at Dana-Farber. “The fact that it takes different forms and involves different types of polyps suggests that there may be multiple biological pathways involved in its development. We’re working to better understand these pathways in order to improve treatment of it and other treatment-related conditions.”

Disclosure: The study was supported by the National Institutes of Health, The Pussycat Foundation Helen Gurley Brown Presidential Initiative, and an American Cancer Society Mentored Research Scholar Grant. For full disclosures of the study authors, visit cancerpreventionresearch.aacrjournals.org.