Experts publish action plan to address appendiceal cancer enigmas

Appendiceal cancer is a rare cancer without standardized screening guidelines, risk factors or tumor classifications — a situation that often results in late diagnosis and poor prognosis.  

Up to 1 of every 2 patients is diagnosed with distant metastatic disease, and five-year survival rates vary between 10% and 63%. A team of experts has identified six key research priority areas to deliver a fundamental understanding of appendiceal tumors and to improve treatments and outcomes for patients. Research to advance treatments for this rare cancer is critical.

The recommendations published in Nature Reviews Cancer are the result of a concerted focus by the Appendix Cancer Pseudomyxoma Peritonei (ACPMP) Research Foundation to better understand the disease that afflicts an estimated 3,000 new patients across all age groups each year. The incidence could be higher because of the challenges accurately diagnosing the disease and identifying the tumor type, the researchers noted.

“The rising burden of appendiceal cancer has illuminated the rudimentary knowledge gaps — spanning from genomes to generations — in our understanding of this rare cancer. By establishing this first-ever research ‘road map’ for appendiceal tumors, we aim to drive collaborative and transformative research discoveries that ultimately will lead to improvements in disease detection, diagnosis, treatments and outcomes for our patients,” said Andreana Holowatyj, PhD, MSCI, assistant professor of Medicine at Vanderbilt University Medical Center and chair of the Scientific Advisory Board for the ACPMP Research Foundation, the article’s lead author.

The recommendations arose from the inaugural ACPMP Research Foundation Scientific Think Tank, sponsored by ACPMP and chaired by Holowatyj at the Vanderbilt-Ingram Cancer Center (VICC) in December 2023. The Think Tank showcases the benefits for scientific collaborations, for robust investments in rare cancer research, and for informing evidence-based medicine. The ongoing effort continues to be a catalyst for revolutionizing the field of research for appendix cancer.

Twenty leading experts on appendiceal cancer met at the Think Tank, and a study group from that meeting are authors of the article.

"This Think Tank and the subsequent publication mark a watershed moment for appendix cancer research," said Deborah Shelton, JD, Executive Director of ACPMP Research Foundation and co-author of the article. "For far too long, appendix cancer has remained underfunded and underresearched, leaving patients with limited options. These research priorities provide a clear path forward, and ACPMP is committed to ensuring the necessary funding and resources to propel these efforts."

The six research priorities:

• Refining histopathological classification – Appendix tumors are not a single entity. Variability of terminology for appendix tumor classification is a challenge due to the rarity of the cancer and supports the need for expert pathology review of appendix tumors among all patients. Consistent application of tumor classification and grading, digitizing histology for tumor detection, and leveraging computational approaches to refine tumor diagnosis are needed.

• Molecular characterization of appendix tumors – The discovery of appendix tumor cells most often occurs postappendectomy when the entire appendix has been removed prior to cancer diagnosis. Preserving and molecular profiling of this tissue are necessary to establish a composite multiomics view of appendiceal tumors.

• Defining the appendiceal tumor microenvironment – A better understanding of the dynamic ecosystem surrounding tumor cells will yield new information for treating appendiceal cancer as well as understanding tumor evolution and disease progression. This information should also be used to contribute to a molecular atlas for appendix tumors.

• Development of disease-specific models – The number of appendix tumor models is extremely limited. Research continues on developing patient-derived organoids to support preclinical testing of new therapeutic drugs.

• Clinical studies of appendix tumors – Collaborative, multicenter efforts — such as the Genetics of Appendix Cancer (GAP) Study at VICC, as well as the development of clinical trials in appendix tumors will yield evidence-based, clinically impactful advancements in this rare cancer.

• Appendix cancer on a population level – Population studies will help researchers identify potential risk factors and/or exposures associated with appendix tumors and address distinct care needs of patients with appendix tumors. These studies will deliver key data to establish early detection strategies, support clinical trials, improve clinical practice and impact public policy.

The study’s other authors include Michael Overman, MD, Konstantinos Votanopoulos, MD, PhD, Andrew Lowy, MD, Patrick Wagner, MD, Mary Kay Washington, MD, PhD, Cathy Eng, MD, Wai Chin Foo, MD, Richard Goldberg, MD, Mojgan Hosseini, MD, Kamran Idrees, MD, MSCI, MMHC, Douglas Johnson, MD, MSCI, Ardaman Shergill, MD, Erin Ward, MD, and Nicholas Zachos, PhD.

Their work was supported by the ACPMP Research Foundation, Vanderbilt-Ingram Cancer Center and NIH/NCI (P50CA236733).