How is ovarian cancer staging determined?
Staging is the process of classifying a tumor according to the extent to which it has spread in the body at the time of diagnosis.
Ovarian cancer staging:
- Stage 1: Limited to one or both ovaries
- Stage 2: Limited to the pelvis
- Stage 3: Disease outside of the pelvis, but limited to the abdomen, or lymph node involvement, but not including the inside of the liver
- Stage 4: Disease spread to the liver or outside of the abdomen
Complete staging of an ovarian cancer includes hysterectomy, removal of the ovaries, tubes, pelvic and aortic lymph node biopsies or dissection, biopsies of the omentum (a large fatty structure that provides support for abdominal organs), and peritoneal (lining tissue of the abdomen) biopsies.
Ovarian cancer staging is determined surgically, unless it is stage 4 (metastasis outside of the abdomen, or metastasis to the liver -- not on the surface of the liver). If it is stage 4, or very advanced stage 3, then often this is proven with biopsy, and chemotherapy may start neoadjuvantly (before surgery). If the disease is not obviously stage 4, then aggressive surgical staging and debulking (see next section) often is considered. This decision is based on the health of the patient, as well as the judgment of the surgeon as to the chance of achieving an optimal debulking (see treatment below).
What is the treatment for ovarian cancer?
Epithelial ovarian cancer treatment most often consists of surgery and chemotherapy. The order is best determined by a gynecologic oncologist.
Surgery is used for both staging and debulking. Staging is the determination of the extent to which as cancer has spread in the body. Debulking is removing as much of the tumor as possible. If one imagines a handful of wet sand thrown on the ground, you will see small piles and bigger piles. This is often how the abdomen looks when in surgery. It is the job of the surgeon to remove, (also known as debulking) as many of these masses as possible. This surgery usually results in removal of both tubes and ovaries, the uterus (hysterectomy), removal of the omentum (omentectomy -- a large fat pad that hangs off of the colon), lymph node biopsies, and any other organ involved in the disease. This can mean a portion of the small bowel, large bowel, liver, the spleen, the gallbladder, a portion of the stomach, a portion of the diaphragm, and removal of a portion of the peritoneum (a thin lining in the abdomen that covers many of the organs and the inside of the abdominal wall). Done properly, this can be a very extensive surgery. The patients who live the longest have all of the visible nodules taken out at time of surgery. To accomplish an "optimal debulking," at minimum, no individual nodule greater than 1 cm should be left behind. If this cannot be done, the patient is brought back to the operating room for a second surgery after a few rounds of chemotherapy (neoadjuvant chemotherapy and interval debulking surgery).
It should be noted that now many gynecologic oncologists believe that optimal debulking should mean that there is no visible disease left at the time of surgery. This has been a shift over the last years. Historically, the goal was to leave no individual nodule greater than 2 cm behind. This has steadily progressed to the point where the term optimal debulking is now accepted by many to mean that there is no disease left to remove. As we have progressed to this point, surgery has become more involved, on a more routine basis. This has led to a concern about undertreatment of elderly patients due to a fear that they cannot survive the surgical risks.
Any patient healthy enough to tolerate chemotherapy will often benefit greatly from its use. The drugs used in ovarian cancer tend to have fewer side effects, and thus are easier to tolerate than many other chemotherapy drugs. Currently, there are two ways to give chemotherapy in ovarian cancer. Traditionally, it is given into the vein intravenously (IV). When initially diagnosed, the usual first-line approach is to give a combination of a platinum drug (typically carboplatin) and a taxane drug, such as paclitaxel (Taxol) or docetaxel (Taxotere).
Another way of giving the chemotherapy is to place it directly into the abdomen (intraperitoneal or IP). In many studies, intraperitoneal administration has been shown to significantly increase survival. This is most often used after optimal surgical debulking. Currently, the drugs used are cisplatin and paclitaxel.
Targeted therapy is a type of treatment that uses drugs or other treatments to identify and attack (target) specific cancer cells without harming normal cells.
The drug bevacizumab is an example of targeted therapy that has been used in the treatment of advanced ovarian cancer. Bevacizumab (Avastin) is a monocolonal monoclonal antibody that targets the development of blood vessels by a tumor.
Other targeted therapies for ovarian cancer include a group of drugs known as poly (ADP-ribose) polymerase inhibitors (PARP inhibitors). These drugs block an enzyme necessary for DNA repair and may cause cancer cells to die. Olaparib (Lynparza) and niraparib (Zejula) are PARP inhibitors that may be used to treat advanced ovarian cancer.
Stromal and germ cell ovarian tumors are most often treated with a combination of chemotherapy drugs. There is much less research on these as they are more curable and much less common than epithelial tumors. Because of their rarity, it will be very difficult to find effective new treatments.
The Gynecologic Oncology Group is a national organization that sponsors clinical trials in gynecologic cancers. Patients can ask their physician if they are eligible for a trial that may help them, as this is how new drugs are discovered. If a doctor or hospital does not participate in the GOG trials, a doctor can often contact a regional center that does.
Immunotherapy is a treatment that uses the patient's immune system to fight cancer. It is now used in the management of a number of different types of cancer. With immunotherapy, substances made by the body or made synthetically are used to strengthen the body's natural defenses against cancer.