The optimal treatment of ovarian cancer requires a combination of surgery, systemic treatment with precision cancer medicines or chemotherapy, and occasionally radiation therapy. Specific treatment for an individual is personalized and can depend on both the stage and the genomic profile of the cancer.1,2,3,4,5
Surgery for Ovarian Cancer
The role of surgery in the initial management of ovarian cancer is to obtain a biopsy specimen of the cancer to confirm the diagnosis, determine the stage of the cancer and to provide local treatment of the cancer in the pelvis and abdomen. The tissue sample is also evaluated for prognostic information and may be sent for genomic testing to determine whether any precision cancer medicines can be used.
Radiation Therapy for Ovarian Cancer
Radiation therapy or radiotherapy uses high-energy rays to damage or kill cancer cells by preventing them from growing and dividing. Similar to surgery, radiation therapy is a local treatment and is not useful in eradicating cancer cells that have already spread to other parts of the body. Radiation therapy may be externally or internally delivered. External radiation delivers high-energy rays directly to the tumor site from a machine outside the body. Internal radiation, or brachytherapy, involves the implantation of a small amount of radioactive material in or near the cancer.
Systemic Therapy: Precision Cancer Medicine, Chemotherapy, and Immunotherapy
Systemic therapy is any treatment directed at destroying cancer cells throughout the body. Many patients, even those with early stage ovarian cancer already have small amounts of cancer that have spread outside the ovaries and pelvis. These cancer cells cannot be treated with surgery and require systemic treatment to decrease the chance of a cancer recurrence. More advanced cancers that cannot be treated with surgery can only be treated with systemic therapy.
Neoadjuvant therapy: Systemic therapy administered as part of the initial treatment plan before surgery is called “neoadjuvant” therapy and is administered to shrink the cancer allowing for easier and more thorough surgical removal. Neoadjuvant therapy typically consisting of 3 cycles of chemotherapy prior to surgical cytoreduction and reduces the side effects of surgery and leads to more optimal cancer debulking.6
Adjuvant therapy: Systemic therapy administered after surgical removal of cancer is called adjuvant therapy and considered standard treatment for ovarian cancer.
Maintenance Therapy: Following the primary treatment of ovarian cancer with surgery and neoadjuvant and adjuvant chemotherapy additional treatment with “maintenance therapy” may also be recommended. Maintenance therapy is also systemic therapy administered with the goal to “maintain” a remission or prevent or delay the cancer’s return if the cancer is in remission after initial treatment. Some doctors believe the term “continuous therapy” is more appropriate since the cancer is essentially being treated on an ongoing basis.5,7,8,9
The initial treatment of ovarian cancer may consist of neoadjuvant and adjuvant therapy and more than one surgery to achieve the best outcomes.
Systemic therapies commonly used in the treatment of ovarian cancer include:
Chemotherapy
Chemotherapy is any treatment involving the use of drugs to kill cancer cells. Cancer chemotherapy may consist of single drugs or combinations of drugs. Chemotherapy drugs cannot tell the difference between a cancer cell and a healthy cell. Therefore, chemotherapy often affects the body’s normal tissues and organs, which can result in complications or side effects. In order to more specifically target the cancer and avoid unwanted side effects researchers are increasingly using precision cancer medicines.
Initial chemotherapy treatment of ovarian cancer typically consists of a combination of platinum and taxane chemotherapy. These and other chemotherapy drugs are used for recurrent or resistant cancer.
Precision Cancer Medicines
Through genomic-biomarker testing performed on a biopsy of the cancer or from a blood sample doctors are increasingly able to define the genomic alterations in a cancers DNA that are driving the growth of a specific cancer. Once a genetic abnormality is identified, a precision medicine can be designed to target a specific mutation or other cancer-related change in the DNA programming of the cancer cells. All patients should discuss the role of genomic testing in order to determine whether precision cancer medicines can be used to treat their cancer.
PARP Inhibitors: The poly ADP-ribose polymerase (PARP) enzyme plays a role in DNA repair, including the repair of DNA damage from chemotherapy. A new class of precision cancer medicines that target and inhibit this enzyme may contribute to cancer cell death and increased sensitivity to chemotherapy and are called PARP inhibitors. By blocking this enzyme, DNA inside the cancerous cells is less likely to be repaired, leading to cell death and possibly a slow-down or stoppage of tumor growth.8,9
Intraperitoneal chemotherapy (IP) is a type of regional chemotherapy that is used to treat some stage III ovarian cancers. During IP chemotherapy the anticancer drugs are infused directly into the peritoneal cavity (the space that contains the abdominal organs) through a thin tube. HIPEC: Hyperthermic (or Heated) Intraperitoneal Chemotherapy is a surgical procedure where surgeons pump a powerful dose of heated chemotherapy inside a patient’s abdomen. HIPEC Intraperitoneal (IP) delivers chemotherapy directly into the abdominal cavity, where there is the greatest number of cancer cells. The chemotherapy is administered through a large catheter that is placed into the abdomen during the surgery to remove the cancer. The 108-degree chemotherapy bath circulates throughout the peritoneal cavity, delivering highly concentrated doses of hot chemotherapy. After about 90 minutes of the infusion, the chemo is washed out and incisions are closed.
Ovarian Cancer Stages
Following surgical removal and staging of ovarian cancer, a final stage will be given. A Roman numeral from I to IV describes the stage and a letter from “A” to “C” describes a sub-stage. All new treatment information concerning ovarian cancer is categorized and discussed by the stage.
Stage I: Cancer is found only in one or both of the ovaries. Cancer cells may also be found in abdominal fluid, or ascites.
Stage II: Cancer is found in the ovaries and has spread to the uterus (womb), the fallopian tubes, or other areas within the pelvis. Cancer cells may also be found in abdominal fluid, or ascites.
Stage III: Cancer is found in the ovaries and has spread to other body locations within the abdomen, such as the surface of the liver, intestine or lymph nodes.
Stage IV: Cancer is found in the ovaries and has spread outside the abdomen or inside of the liver.
Recurrent or Refractory: Recurrent disease means that the cancer has returned (recurred) after it has been treated. Refractory disease means the cancer is no longer responding to treatment.
References
1 American Cancer Society Cancer Facts & Figures 2017. Available at: http://www.cancer.org/docroot/STT/stt_0.asp
2 Chobanian N, Dietrich CS. Ovarian Cancer. Surgical Clinics of North America. 2008; 88:285-99, vi.
3 Ries LAG, Melbert D, Krapcho M, Stinchcomb DG, Howlader N, Horner MJ, Mariotto A, Miller BA, Feuer EJ, Altekruse SF, Lewis DR, Clegg L, Eisner MP, Reichman M, Edwards BK (eds). SEER Cancer Statistics Review, 1975-2005, National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/csr/1975_2005/
4 Armstrong, D. Ovaries and fallopian tubes. In: Abeloff MD ed. Abeloff’s Clinical Oncology, 4th ed. Philadelphia: Churchill Livingstone, 2008: 1827-50.
5 Wright JD, Herzog TJ, Siddiq Z, et al. Failure to Rescue As a Source of Variation in Hospital Mortality for Ovarian Cancer. Journal of Clinical Oncology. 2012; 30(32): 3976-3982.
6 Wright AA, et al. J Clin Oncol 2016; 34:3460-73
7 Burger RA, Brady MF, Bookman MA et al. Phase III trial of bevacizumab (BEV) in the primary treatment of advanced epithelial ovarian cancer (EOC), primary peritoneal cancer (PPC) or Fallopian tub cancer (FTC): A Gynecologic Oncology Group study. Presented at the 2010 annual meeting of the American Society of Clinical Oncology. June 4-8, 2010. Chicago, IL. Abstract LBA 1.
8 J Clin Oncol. 2019 Jun 19. Epub ahead of print
9 Tesaro Inc., press release. Tesaro’s niraparib significantly improved progression-free survival for patients with ovarian cancer in both cohorts of the phase 3 NOVA trial. Available at: http://ir.tesarobio.com/releasedetail.cfm?ReleaseID=977524. Accessed July 6, 2016.