"Most ovarian cancer patients come to the hospital for the first time when the cancer is at an advanced stage, between stages 3 and 4. Many women only get cervical cancer screenings, but it is also essential to have an ovarian ultrasound examination. From the standpoint of discovering ovarian cancer, I think even the annual health check-up intervals are too long."
Lee Eun-joo, a professor at the Department of Obstetrics and Gynecology at Chung-Ang University Hospital, said on the 8th at Chung-Ang University Hospital in Dongjak District, Seoul, "Ovarian cancer often goes unnoticed in the early stages because there are no significant symptoms. It is crucial for women to undergo gynecological check-ups regularly and more frequently." He noted, "Many patients say there were no issues when they had their health check-up last year," adding that "this implies the need to shorten the typical annual interval for ovarian cancer screenings."
Professor Lee Eun-joo began her residency at Samsung Medical Center's Department of Obstetrics and Gynecology and trained at the U.S. MD Anderson Cancer Center and the Sidney Kimmel Cancer Center. She currently serves as the Chairperson of the Surgery Committee for the Korean Gynecological Oncology Society (KGOS), is the associate editor of the Journal of Korean Obstetrics and Gynecology, a member of the Scientific Committee of the Korean Society of Gynecologic Oncology, chairperson of the Ovarian Cancer Surgery Committee of the Korean Gynecological Oncology Society, a specialist committee member of the Ministry of Food and Drug Safety, and the president of the Korean Society of Pelvic Pain.
Ovaries are reproductive organs located on both sides of the uterus that secrete female hormones. Even when diagnosed with ovarian cancer, patients typically show little physical change or symptoms in the early stages. Because the ovaries are located deep within the pelvis, unless the tumor grows significantly, it may not be visible externally, and even if there is fluid accumulation, it can easily be mistaken for simple bloating. Due to the difficulty of detection in the early stages, ovarian cancer has the highest mortality rate among female cancers.
The primary cause of ovarian cancer identified in academia is ovulation. Ovulation is the process during which a mature egg is released from the ovaries, usually occurring monthly in women of childbearing age. Professor Lee explained, "Every time ovulation occurs, the epithelial tissue on the ovarian surface ruptures and repairs, resulting in increased cell division. The more cell divisions, the higher the chance of errors and mutations during the gene replication process, which can lead to the development of cancer cells into ovarian cancer."
The number of ovulations serves as a risk factor for ovarian cancer. Women with no childbirth history, those with early menarche or late menopause, and women over 40 are categorized as high-risk groups for this reason. Additionally, women with a family history of BRCA1 and BRCA2 gene mutations, Lynch syndrome, and endometriosis also belong to the high-risk group. Notably, if there is a mutation in the genes related to breast and ovarian cancer, known as BRCA, the lifetime risk of developing ovarian cancer is reported to reach 27% to 44%.
Since a higher number of ovulations increases the risk of ovarian cancer, contraceptive pills are considered a preventive measure against ovarian cancer. This is because contraceptive pills suppress ovulation. Medical textbooks state that using contraceptive pills for more than five years can reduce the risk of ovarian cancer by up to 50%.
Professor Lee noted, "There is a lot of misinformation and misunderstanding that fosters an unfounded fear of oral contraceptives in our country, making women reluctant to take them," adding, "Contraceptives can indeed serve as an active preventive measure from the perspective of women's health."
Women with BRCA gene mutations can also prevent ovarian cancer by undergoing oophorectomy and salpingectomy after childbirth. When a hysterectomy is performed due to uterine issues, removing the ovaries and fallopian tubes together can reduce the risk of ovarian and fallopian tube cancers.
There are various treatment methods for ovarian cancer, depending on the patient's situation, but they generally involve a combination of tumor-reduction surgery and chemotherapy. In cases where the surgical risk is high or there is significant metastasis, chemotherapy may be administered first before surgery. For younger female patients, only part of the ovary may be removed to preserve fertility.
Professor Lee stated that one crucial factor for patients choosing a hospital is the hospital's collaborative treatment system. He pointed out that large hospitals, which often experience high patient influx, may struggle with effective collaboration.
Professor Lee emphasized, "We are no longer in an era where one famed doctor saves a patient," adding, "Especially for ovarian cancer, which requires a broad surgical approach, cooperation among experts in surgery, thoracic surgery, urology, and gynecology, as in our hospital, is essential."
In cases where the disease is at stage 4 or the tumor cannot be completely removed through surgery, the drug Bevacizumab is used to prevent the tumor from growing. For patients with BRCA gene mutations or those with positive HRD (Homologous Recombination Deficiency), PARP inhibitors may be used as first-line maintenance therapy.
HRD refers to a genetic defect that hinders the normal repair of damaged DNA. PARP inhibitors are treatments that block the function of the PARP enzyme, impairing the cancer cells' ability to repair their DNA; examples include Olaparib and Niraparib.
The five-year survival rate for ovarian cancer patients in the country has marginally increased from 61.4% in 2006-2010 to 65.8% in 2018-2022. However, with the recent emergence of new drugs, the treatment outcomes for ovarian cancer in the country are also improving, which Professor Lee anticipates will enhance overall survival rates.
Professor Lee stated, "Bevacizumab was approved for use in the country in 2007 as part of combination and maintenance therapies, but it did not dramatically increase the overall survival rate for ovarian cancer," and added, "The expansion of insurance coverage for using PARP inhibitors in patients with HRD-positive ovarian cancer last October has significantly improved the disease-free survival rate for this group."
According to Professor Lee, PARP inhibitors reduce the risk of recurrence by 60% to 70% in ovarian cancer with BRCA mutations. For HRD-positive patients, the risk is reduced by 50%, and in cases of recurrent ovarian cancer sensitive to platinum-based chemotherapy, the subsequent recurrence risk is reduced by 70%. Professor Lee described this as "a groundbreaking statistic in the history of ovarian cancer treatment," noting that while the tests to confirm HRD positivity are not covered by insurance and present a burden for domestic patients, having available treatments provides hope for patients and doctors.
Professor Lee is also researching treatment methods for ovarian cancer patients who do not respond to existing chemotherapy drugs. He stated, "I discovered the DKK3 gene, which inhibits tumor cells," and added, "I also found that glycosylation, the addition of sugar to proteins, is crucial for the activity of the DKK3 protein."
DKK3 inhibits cancer cells by blocking cell signaling. Professor Lee mentioned that he is in the process of filing a patent for a therapy using glycosylated DKK3. He noted, "We developed a drug that expresses DKK3 for ovarian cancer that does not respond to existing chemotherapy drugs in collaboration with Chung-Ang University School of Pharmacy's research team," and added, "We are currently verifying the treatment effects using organoids, mini-organs created from cultured patient cancer tissues."
Results from the organoid research are expected to be released around 2027. Professor Lee stated, "Thanks to the patients who donated their cancer tissues, we were able to create personalized cancer organoids for each patient."