Appendic cancer is very rare, accounting for less than 1% of gastrointestinal tumors, and there is little scientific data on the disease, which means that the current guidelines for the treatment of colon cancer are recommended for patients with appendic cancer. To understand why some patients with appendix cancer respond to standard treatment for colon cancer, while others do not, the researchers performed a genetic analysis of 703 appendix cancer samples. This is by far the largest study of appendix cancer to compare the mutations present in the two cancer types.
The results of the study confirmed that genetic mutations in appendix cancer are different from those in colon cancer. TP53 and GNAS mutations are good predictors of survival in patients with appendix cancer. For rare appendix cancers, obtaining molecular maps will help determine potential treatment options because we do not have clinical trial data to guide standard treatment like other cancers. Equally important, the mutation spectrum can be used as a biomarker to distinguish high-risk patients who need intensive treatment to isolate them from low-risk patients.
Retrospective study found that appendix cancer includes five different subtypes: mucinous adenocarcinoma ( 46%), adenocarcinoma (30%), goblet cell carcinoma (12%), peritoneal pseudomyxoma (7.7%), and signet ring Cell carcinoma (5.2%). GNAS gene mutations that are rare in colon cancer are very common in appendix cancer, especially mucinous adenocarcinoma (52%) and peritoneal pseudomyxoma (72%). The median survival of patients with tumors with GNAS mutations is almost 10 years, while the median survival of patients with tumors with TP53 mutations is only three years, and the median survival of patients without these two gene mutations is 6 years.
This surprising discovery raises the question of whether patients with early-stage GNAS-mutant tumors need to be treated with chemotherapy because it may be cured by surgery alone, so more research is needed to prove it.