What is rare cancer?
The definition of rare cancer is based on its frequency within the population. A disease is considered rare when it affects fewer than 1 in 2,500 individuals. Therefore, a rare cancer is a type of tumor that is rarely observed in the population. Most tumors occur sporadically and are classified as sporadic cancers. In contrast, many rare cancers are hereditary and associated with genetic diseases.
Ovarian cancer is a type of cancer that develops in the ovaries. It can occur in different parts of the ovary, including the germ cells (the eggs), stromal cells (which form connective tissue and can secrete hormones), and epithelial cells (which line the surface of the ovary) (American Cancer Society, 2021). These differences in cellular origins give rise to tumors of different subtypes. What we call a rare ovarian cancer is really a rare ovarian tumor subtype.
Ovarian cancer is usually diagnosed through imaging tests such as ultrasounds, CT scans, or MRI scans, as well as blood tests that measure levels of certain proteins such as CA-125 (American Cancer Society, 2021). Treatment options may include surgery to remove the ovaries, chemotherapy, and radiation therapy. The best course of treatment for ovarian cancer depends on factors such as the stage of the cancer, the patient’s overall health, and their individual needs and preferences (Mayo Clinic, 2021).
Ovarian cancer is usually diagnosed through imaging tests such as ultrasounds, CT scans, or MRI scans, as well as blood tests that measure levels of certain proteins such as CA-125 (American Cancer Society, 2021). Treatment options may include surgery to remove the ovaries, chemotherapy, and radiation therapy. The best course of treatment for ovarian cancer depends on factors such as the stage of the cancer, the patient’s overall health, and their individual needs and preferences (Mayo Clinic, 2021).
Some of the symptoms of ovarian cancer may include abdominal bloating, pelvic pain and changes in bowel or bladder habits, among others (Mayo Clinic, 2021). Overall, early detection and treatment are key to improving the prognosis of ovarian cancer. Women experiencing symptoms should speak to their healthcare provider about the possibility of ovarian cancer and should consider undergoing screening tests (American Cancer Society, 2021).
Ovarian tumor types
Subtypes of ovarian tumors are classified based on their cell type, behavior, and genetic mutations using the World Health Organization (WHO) classification system (American Cancer Society, 2021).:
- Epithelial tumors: Are the most common subtype, and they appear in adult women. These tumors originate from the cells that line the surface of the ovary and account for about 90% of all ovarian tumors. The subtypes of epithelial tumors include serous, mucinous, endometrioid, clear cell, and transitional cell tumors.
- Germ cell tumors: These tumors originate from the cells that produce eggs and account for about 3% of all ovarian tumors. The subtypes of germ cell tumors include teratomas, dysgerminomas, endodermal sinus tumors, and choriocarcinomas. They can appear in the pediatric and early adulthood populations.
- Sex cord-stromal tumors: These tumors originate from the cells that produce female hormones and account for about 2% of all ovarian tumors. The subtypes of sex cord-stromal tumors include granulosa cell tumors, Sertoli-Leydig cell tumors, and fibromas. They can appear at any age in life.
- Other rare types of ovarian tumors: These include metastatic tumors, which originate in other parts of the body and spread to the ovaries, borderline ovarian tumors, which have abnormal cells but are not invasive like cancer cells; and SCCOHT a very rare but aggressive ovarian cancer which can presents from infancy up to the 40s.
Ovarian tumors can have different behaviors and can be benign, borderline, or malignant. Malignant tumors can be further classified based on their stage, which reflects how far the cancer has spread.
Ovarian tumor types
Subtypes of ovarian tumors are classified based on their cell type, behavior, and genetic mutations using the World Health Organization (WHO) classification system (American Cancer Society, 2021).:
- Epithelial tumors: Are the most common subtype, and they appear in adult women. These tumors originate from the cells that line the surface of the ovary and account for about 90% of all ovarian tumors. The subtypes of epithelial tumors include serous, mucinous, endometrioid, clear cell, and transitional cell tumors.
- Germ cell tumors: These tumors originate from the cells that produce eggs and account for about 3% of all ovarian tumors. The subtypes of germ cell tumors include teratomas, dysgerminomas, endodermal sinus tumors, and choriocarcinomas. They can appear in the pediatric and early adulthood populations.
- Sex cord-stromal tumors: These tumors originate from the cells that produce female hormones and account for about 2% of all ovarian tumors. The subtypes of sex cord-stromal tumors include granulosa cell tumors, Sertoli-Leydig cell tumors, and fibromas. They can appear at any age in life.
- Other rare types of ovarian tumors: These include metastatic tumors, which originate in other parts of the body and spread to the ovaries, borderline ovarian tumors, which have abnormal cells but are not invasive like cancer cells; and SCCOHT a very rare but aggressive ovarian cancer which can presents from infancy up to the 40s.
Ovarian tumors can have different behaviors and can be benign, borderline, or malignant. Malignant tumors can be further classified based on their stage, which reflects how far the cancer has spread.
