Ovarian cancer develops when the cells in the ovaries start to reproduce and grow out of control. This interferes with normal cell production and causes tumors to form.

Ovaries contain three different types of cells:

  • epithelial cells, which cover the outside of the ovary
  • cells that produce eggs
  • cells that produce hormones

Each type of cell can develop tumors. However, most ovarian tumors form in the epithelial cells.

Ovarian cancer accounts for just 3 percent of cancers in women, according to the Centers for Disease Control and Prevention (CDC). However, the American Cancer Society (ACS) states that it’s the fifth most fatal cancer among women.

Ovarian cancer often lacks clear symptoms in its early stages. When symptoms do occur, they can easily be mistaken for other conditions.

Symptoms of ovarian cancer can include:

Symptoms get worse as ovarian tumors grow and begin to take up more space in the abdomen. Tumors can press against other organs and interfere with normal body functions.

Several factors can cause women with ovarian cancer to gain weight.

Tumors are the major cause. Ovarian tumors are buried deep within the abdomen. They often aren’t discovered until they’re relatively large. They can cause some abdominal discomfort in the early stages of ovarian cancer, but can be mistaken for a stomachache or another nonthreatening condition.

Tumors grow and cancer spreads, taking up more space inside the uterus if left untreated. Tumors can grow quite large before causing symptoms. This is because the uterus is designed to hold a fetus. Deposits of cancerous cells 2 centimeters or more are often found in the abdomen during stage 3C of ovarian cancer.

Constipation is another cause of weight gain. This can occur when the cancerous growth on the ovaries spreads to other parts of the uterus and abdomen and presses against the intestine or colon. This interferes with normal digestion.

Fluid can build up in the abdomen as tumors grow in or on the ovaries and cancerous cell deposits spread to nearby organs.

Seek medical attention if you experience unexplained weight gain along with abdominal pain, digestive discomfort, and urinary or sexual discomfort. Treatment for ovarian cancer varies depending on factors like:

  • stage of the cancer
  • type of tumor
  • size of tumor
  • whether you want to have children in the future

Surgical removal of all or part of the tumor followed by chemotherapy to kill remaining cancer cells is the most common treatment. Removing a large tumor from the body can cause immediate weight loss. Weight gain directly attributable to ovarian cancer will often reverse due to side effects of chemotherapy, such as nausea and loss of appetite.

The relationship between weight and ovarian cancer is still not completely clear. Studies have been inconclusive. However, the ACS found that obesity increases the risk for various types of cancers, including ovarian cancer. So it’s important to lead an active lifestyle and maintain a healthy weight.