Adenocarcinoma de reto

Revisão e relato de caso acerca dos fatores de risco, diagnóstico e manejo

Abstract

Approximately 30% to 40% of colorectal cancer cases are rectal adenocarcinoma, which is the most prevalent type of the disease. The majority of those affected are over 50 years old, although younger individuals are also increasingly being affected. A family history of colorectal cancer, inflammatory bowel diseases, high consumption of red and processed meats, obesity, sedentary lifestyle, alcohol use, and smoking are risk factors.

From a pathological perspective, the glandular epithelial cells that line the rectal mucosa are the origin of rectal adenocarcinoma. Generally, a series of genetic and epigenetic alterations causes dysplasia, followed by the formation of adenomas, which can eventually lead to aggressive cancer. The APC, KRAS, TP53 genes, and the Wnt signaling pathway are the ones with the most frequent mutations. These changes result in uncontrolled cell proliferation, evasion of apoptosis, and invasive potential, allowing cancer cells to spread to nearby tissues and, in more advanced stages, to distant organs such as the liver and lungs.

The patient in the case under analysis was diagnosed after the age of 50, with a tumor that presented circumferential parietal thickening with an extension of 32 mm involving the middle and lower rectum, located about 78 mm from the anal verge, with slight extension to the mesorectal fat and apparent local vascular involvement. The patient underwent radiotherapy and chemotherapy, as well as surgical intervention.

In summary, understanding the molecular pathways underlying rectal adenocarcinoma is crucial for formulating more effective therapeutic approaches. These may involve a combination of surgical techniques, chemotherapy, radiotherapy, and, in certain situations, targeted medications that depend on the genetic composition of the tumor. Improving patient prognosis and survival requires early detection and appropriate management.