Ovarian cancer is often described as a single disease, but it is actually a group of cancers that affect the ovaries, fallopian tubes, and the abdominal lining. Contemporary scientific understanding has shifted the focus regarding the origin of the most common and aggressive type of the disease. The question of whether this cancer can still occur after the fallopian tubes are removed is central to prevention efforts. The answer is yes, ovarian-type cancer can still occur, but the risk is significantly reduced by this surgical intervention.
Where Ovarian Cancer Often Begins
The traditional belief that ovarian cancer begins on the surface of the ovary has been largely replaced by a new theory based on microscopic evidence. Research now suggests that a majority of high-grade serous ovarian carcinoma (HGSOC), which accounts for about 70% of all ovarian cancer cases, actually begins in the fallopian tubes.
This modern understanding centers on tiny, pre-cancerous lesions known as Serous Tubal Intraepithelial Carcinoma (STIC). These lesions are primarily found in the fimbriated, or finger-like, ends of the fallopian tubes. STIC lesions are believed to be the precursor to HGSOC, with cancerous cells later shedding from the tube and implanting on the ovary or the peritoneum.
The STIC theory has changed surgical practice, leading to the recommendation of “opportunistic salpingectomy”—the removal of the fallopian tubes during other pelvic surgeries like hysterectomy. By removing the tubes, the primary site where the most aggressive type of ovarian cancer is thought to start is eliminated.
Remaining Risk After Removing Fallopian Tubes
Removing the fallopian tubes (salpingectomy) or removing both the tubes and ovaries (bilateral salpingo-oophorectomy) substantially reduces the risk of ovarian cancer, but it does not eliminate it entirely. The residual risk comes from two main sources: primary peritoneal cancer and the possibility of a true primary ovarian tumor.
Primary Peritoneal Cancer (PPC) is the main concern following the removal of the tubes and ovaries. PPC is biologically and microscopically almost identical to HGSOC. The tissue of the peritoneum, ovaries, and fallopian tubes all share a common embryonic origin.
For women at high genetic risk, such as those with a BRCA1 or BRCA2 mutation, the cumulative risk of developing PPC after risk-reducing surgery is estimated to be between 1% and 4% over 20 years. This risk is notably higher for BRCA1 carriers than for BRCA2 carriers. For the general population, studies show that bilateral salpingectomy alone can reduce the risk of ovarian cancer by approximately 50% to 65%.
While rare, true ovarian cancer, which originates from the surface of the ovary itself, is still possible if the ovaries are retained after a salpingectomy. The significant risk reduction achieved by removing the fallopian tubes addresses the most common pathway of the disease, but the shared genetic and cellular landscape of the pelvic organs means a small risk remains.
Managing Other Risk Factors and Surveillance
Genetic and Lifestyle Risk Factors
Genetic factors play a major role in the remaining risk of ovarian-type cancer. Mutations in the BRCA1 and BRCA2 genes are the most well-known, drastically increasing the lifetime risk of both ovarian cancer and primary peritoneal cancer. A strong family history of breast, ovarian, or prostate cancer can also indicate an elevated risk, prompting genetic testing and specialized management.
Other factors can influence a woman’s risk profile. Long-term use of oral contraceptives and having multiple full-term pregnancies are considered protective factors. Conversely, conditions like endometriosis can increase the risk of certain rarer subtypes of ovarian cancer.
Surveillance and Management
For women at average risk, no effective screening tool exists for the early detection of ovarian or peritoneal cancer. For individuals at very high risk who choose not to have surgery, surveillance may be offered. This typically involves a combination of the CA-125 blood test and transvaginal ultrasound, but these methods have not been shown to consistently detect the disease at an early stage.
For those with BRCA mutations, the most effective risk-reducing strategy remains a bilateral salpingo-oophorectomy. This surgery is generally recommended between the ages of 35 and 45, depending on the specific mutation. This timing helps manage the effects of surgically induced menopause. Discussions about hormone replacement therapy are a necessary part of this planning.