Interval Debulking for Ovarian Cancer

Medically Reviewed by Laura J. Martin, MD on July 19, 2022
Written by Janie McQueen
3 min read

Interval debulking surgery, or IDS, is a way to treat advanced – meaning stage III or IV – ovarian cancer when primary surgery isn’t possible. IDS also can be performed as a secondary surgery when primary debulking doesn’t remove enough tumor tissue.

The aim of debulking, also called cytoreductive surgery, is to remove as much tumor tissue as possible. It’s key when your cancer has spread throughout your belly, such as to your colon, spleen, or liver. The goal is to take out all visible cancer and tumors larger than 1 centimeter. Doctors consider this optimal debulking, or optimal cytoreduction.

Debulking also can relieve symptoms of the disease by getting rid of tissue masses that might be pressing against other organs. It can make treatments you receive after surgery, such as chemo, be more effective, too.

It’s key that debulking surgery is performed by a board-certified gynecologic oncologist if available. Due to these specialists’ training and skills, they’re five times more likely to completely remove tumors during ovarian cancer surgery than surgeons that don’t have this area of expertise.

Surgery performed before chemo is called primary debulking surgery (PDS). It’s considered standard treatment. After your surgeon has staged your ovarian cancer – meaning they’ve found out how far the cancer has spread from your ovaries – debulking surgery can be done.

Interval debulking surgery along with neoadjuvant chemotherapy, or NACT-IDS, is usually recommended for people who aren’t good candidates for surgery, or for whom optimal debulking likely isn’t possible with PDS.

NACT uses chemo drugs to try to shrink tumors before any surgery is performed, which is called neoadjuvant therapy. Reasons why you might have NACT-IDS include:

  • The disease spread is extensive. Your surgeon might not feel they can get a good outcome performing surgery first.
  • Primary surgery is considered too high risk. It’s more complex, and can cause problems, including major blood loss.
  • You have other health reasons that make surgery more risky.
  • For people who can’t have primary debulking, NACT-IDS increases your chances of having the entire tumor removed, meaning a positive outcome.

About 20% to 30% of people with stage III ovarian cancer, and 40% to 60% of people who have stage IV, receive NACT-IDS treatment.

Other benefits of NACT-IDS may include:

  • It’s not as aggressive as primary debulking surgery. You probably won’t lose as much blood.
  • You’re not as likely to need to go to intensive care.
  • You’ll have a shorter hospital stay because the tumors are smaller.

Interval debulking might also be performed after primary surgery. In this case it’s called a secondary surgery. Reasons you might have it include:

  • Sometimes even high-tech scans and exams don’t show the extent of ovarian cancer. If this happens, and surgery can’t remove all of it, your surgeon might want to perform interval debulking. In this case it’s called a secondary surgery.
  • Your surgeon might suggest interval debulking surgery as a secondary surgery between courses of chemo, if the chemo has been effective.
  • After a first treatment for ovarian cancer, the disease returns most of the time, that is, for more than 7 out of 10 people. Your doctor might opt to do another surgery – an interval debulking surgery – to remove as much of the disease as possible before starting chemo again.

Since primary debulking surgery remains the standard of care, meaning the best treatment known, interval debulking is viewed as an alternative. If you have interval debulking surgery, it’ll be because PDS isn’t an option for some reason. However, your doctor will consider the pros and cons to IDS and discuss it with you. For example, a 2020 study found:

  • The survival rate is higher with PDS than with NACT-IDS. However, it’s key to keep in mind that people who received NACT tended to be older, with more existing conditions going in. They also had more advanced, more aggressive tumors.

Also, an Italian phase III trial found IDS had much lower complication rates after surgery, and fewer deaths after surgery, because the surgery was simpler than PDS.

  • The 2020 study found PDS that had some leftover cancer has an equal survival rate to NACT-IDS with complete removal of cancer tissue. However, the Italian trial found complete cytoreduction is still the key factor in the prognosis for any surgery for advanced ovarian cancer.