Peritoneal cancer is a rare disease affecting the peritoneum, a thin membrane that lines the abdominal cavity. This membrane also covers many organs within the abdomen, functioning to support them and secrete a lubricating fluid that allows organs to move smoothly against each other. Understanding the causes of peritoneal cancer is complex, as it can arise directly from the peritoneum or spread from other cancers.
Primary Peritoneal Cancer: Known Risk Factors
Primary peritoneal cancer originates directly in the peritoneum, and its risk factors often mirror those associated with epithelial ovarian cancer. Age is a factor, with most individuals diagnosed being 60 years or older. Reproductive history also plays a role, as women who have never given birth (nulliparity) or experience infertility may have an elevated risk.
Endometriosis, a condition where tissue similar to the uterine lining grows outside the uterus, can increase the likelihood of developing primary peritoneal cancer. Some research suggests a connection between the use of talcum powder in the genital area and an increased risk. Additionally, postmenopausal hormone replacement therapy and obesity have been identified as potential risk factors.
Metastatic Peritoneal Cancer: Origins and Spread
Peritoneal cancer is most frequently found as a secondary, or metastatic, condition, meaning it originated elsewhere in the body and subsequently spread to the peritoneum. This type of spread is often referred to as peritoneal carcinomatosis. The most common primary cancer sites that metastasize to the peritoneum include ovarian, colorectal, stomach, and pancreatic cancers. Other cancers, such as those of the appendix, breast, and even, less commonly, lung or skin cancers, can also spread to this lining.
Cancer cells typically spread to the peritoneum through a process called transcoelomic dissemination. In this mechanism, cancer cells detach from the primary tumor and shed into the peritoneal fluid within the abdominal cavity. These free-floating cells can then implant on the peritoneal surfaces and grow into new tumors. This spread often indicates a more advanced stage of the original cancer.
Genetic Predispositions
Inherited genetic mutations can significantly increase an individual’s susceptibility to peritoneal cancer, either directly or by raising the risk of other cancers that commonly metastasize to the peritoneum. Mutations in the BRCA1 and BRCA2 genes are among the most well-known genetic factors. These mutations are strongly associated with an increased risk for primary peritoneal cancer, similar to their link with ovarian cancer. Even after preventive removal of the ovaries, individuals with BRCA1 or BRCA2 mutations still have a low, but present, risk of developing primary peritoneal cancer.
Lynch syndrome, another inherited condition, also elevates cancer risk. While primarily linked to colorectal and endometrial cancers, Lynch syndrome increases the risk for other cancers, including ovarian cancer, which can then spread to the peritoneum. These genetic changes impair the body’s ability to repair damaged DNA, leading to a higher chance of cells becoming cancerous.
Other Potential Influences and Unclear Factors
Beyond established risk factors, other potential influences on peritoneal cancer development remain under investigation. Chronic inflammation within the abdomen may contribute to the disease. Conditions such as endometriosis or inflammatory bowel disease, which involve persistent inflammation, could potentially increase the risk.
Environmental exposures, such as asbestos, have also been discussed in relation to peritoneal malignancies. While asbestos is more strongly linked to mesothelioma, a different type of cancer affecting the lining of the lungs or abdomen, its potential role in other peritoneal cancers is considered. Despite these identified factors, it is important to recognize that in many cases, peritoneal cancer develops without any clear, identifiable cause. Ongoing research continues to explore the various pathways and mechanisms that contribute to the development of this complex disease.