Ovarian Cancer : An Overview

Introduction

Ovarian cancer is a significant health concern for women worldwide. It is the seventh most common cancer among women and ranks eighth in cancer-related deaths among women globally. This blog aims to provide a comprehensive overview of ovarian cancer, including its epidemiology, risk factors, pathophysiology, clinical presentation, diagnosis, staging, treatment options, and prognosis.

Epidemiology

Ovarian cancer is a multifaceted disease with a complex epidemiological profile. It predominantly affects postmenopausal women, with the median age of diagnosis being around 63 years old. However, it can occur at any age, and a small percentage of cases are diagnosed in women under the age of 40.

The incidence of ovarian cancer varies geographically, with higher rates reported in developed countries. Some countries with the highest incidence include the United States, Canada, and several European nations. Conversely, lower rates are observed in less developed regions of the world.

Risk Factors

Understanding the risk factors associated with ovarian cancer is essential for early detection and prevention. Several risk factors have been identified, including:

1. Age: As mentioned earlier, advancing age is a significant risk factor for ovarian cancer.
2. Family History: Women with a family history of ovarian cancer or certain other cancers, such as breast or colon cancer, are at increased risk.
3. Genetic Mutations: Mutations in the BRCA1 and BRCA2 genes significantly elevate the risk of ovarian cancer.

BRCA1 and BRCA2 are genes in our DNA that perform essential tasks like repairing damaged DNA and preventing the development of damaged cells which may cause cancer. 

When there are changes in these genes (mutations) they are unable to carry out this function properly.

Particularly, BRCA1 and BRCA2 mutations can increase the risk of Breast or Ovarian cancer in an individual, and sometimes, even other forms of Cancer

4. Reproductive Factors: Factors such as never having given birth, early onset of menstruation, and late onset of menopause can increase the risk.
5. Hormone Replacement Therapy (HRT): Long-term use of estrogen-only HRT has been associated with a higher risk of ovarian cancer.
6. Obesity: Excess body weight may increase the risk of developing ovarian cancer.

Pathophysiology

Ovarian cancer encompasses a group of malignancies that originate in the ovaries.

The most common type is epithelial ovarian cancer (90%), which arises from the epithelial cells covering the ovary’s surface. Less common types include germ cell tumors and stromal cell tumors. ^[1]

Epithelial ovarian cancer occurs mostly in Menopausal women.^[1]

Germ Cell tumors occur more in Young age^[1]

Sex-cord stromal tumors may occur at any age^[1]

The exact cause of ovarian cancer remains unclear, but genetic mutations and the incessant ovulation hypothesis have been proposed as contributing factors. 

The incessant ovulation hypothesis suggests that repeated monthly ovulation causes trauma to the ovarian surface epithelium, leading to genetic mutations and the development of cancer.

Metastasis:

The most common location where extra-abdominal spread frequently occurs is within the pleural space (via transdiaphragmatic lymphatics) leading to malignant pleural effusion in some. In other cases, it tends to spread locally affecting the peritoneal cavity and retroperitoneal nodes^[1]

Hematogenous Metastasis- Liver, Spleen, Lung^[1]

Bone/ Central Nervous System metastasis is very rare^[1]

Clinical Presentation

Ovarian cancer is often referred to as the “silent killer” because it tends to remain asymptomatic until it reaches an advanced stage. Common symptoms and signs of ovarian cancer include:

1. Abdominal Bloating: Persistent bloating that doesn’t resolve with dietary changes or menstruation.
2. Pelvic or Abdominal Pain: Chronic pain in the pelvic or abdominal region.

Germ Cell Malignancy often twists and stretches the infundibulopelvic ligament therefore leading to severe pain.

3. Feeling Full Quickly: A sensation of early satiety or difficulty eating.
4. Changes in Bowel or Bladder Habits: Including constipation, diarrhea, frequent urination, or urinary urgency.
5. Unexplained Weight Loss: Sudden and unexplained weight loss.

It is crucial for healthcare providers to recognize these symptoms and perform appropriate diagnostic tests, especially in postmenopausal women with risk factors.

Diagnosis

Diagnosing ovarian cancer typically involves a combination of clinical evaluation, imaging studies, and laboratory tests. The following diagnostic modalities are commonly employed:

1. Pelvic Examination: The healthcare provider may perform a pelvic exam to check for any palpable masses or abnormalities.
2. Imaging: Transvaginal ultrasound and CT scans are used to visualize the ovaries and assess any potential abnormalities.

Trans Vaginal Ultrasonography is better than CT Scans^[1]

Classic finding in Trans Vaginal Ultrasonography is – a “ Complex cyst” containing both solid and cystic components, sometimes with septations and echogenicity^[1]

3. Tumor Markers: Blood tests for tumor markers such as CA-125 can provide additional information.

CA 125 Levels are elevated in majority of women with Epithelial Ovarian Cancer

Post operatively also, CA 125 levels is a sensitive way to know the treatment response and about disease reoccurrence

4. Biopsy: A tissue biopsy is often necessary to confirm the diagnosis and determine the cancer’s histological type and grade.

Staging

Once ovarian cancer is diagnosed, it is crucial to determine the extent of the disease to guide treatment decisions.

Staging done via Exploratory Laparotomy.

  Ovarian cancer staging is typically done according to the FIGO (International Federation of Gynecology and Obstetrics) system, which includes four stages:

1. Stage I: Limited to the ovaries.
2. Stage II: Spread to the pelvis.
3. Stage III: Spread to the abdomen or lymph nodes.
4. Stage IV: Distant metastasis.

Accurate staging is essential for planning the most appropriate treatment approach.

Treatment Options

The management of ovarian cancer depends on various factors, including the stage of the disease, the histological subtype, the patient’s overall health, and her preferences. Treatment modalities include:

1. Surgery: Surgical removal of the tumor, known as debulking surgery, is a primary treatment for ovarian cancer. It may involve the removal of one or both ovaries, the fallopian tubes, the uterus, and other affected tissues.

Surgery is done to remove large necrotic tumors which may cause impaired chemotherapy delivery^[1]

-Primary Debulking Surgery- first surgery than Chemotherapy

-Interval Debulking Surgery- After 3 cycles of Chemotherapy

2. Chemotherapy: Chemotherapy is typically administered post-surgery to eliminate any remaining cancer cells. Platinum-based regimens are commonly used.

Intraperitoneal Chemotherapy- Fewer systemic complications

3. Targeted Therapy: Some patients, particularly those with specific genetic mutations like BRCA1/2, may benefit from targeted therapies such as PARP inhibitors.

Radiation Therapy: Radiation therapy is rarely used in ovarian cancer, but it may be considered in specific cases.

Prognosis

The prognosis for ovarian cancer varies widely depending on the stage at diagnosis and the type of cancer. In general:

1. Early-Stage Disease: When ovarian cancer is diagnosed at an early stage (Stage I or II), the prognosis is relatively favorable, with a five-year survival rate of 80% or higher.
2. Advanced-Stage Disease: Unfortunately, most cases are diagnosed at an advanced stage, leading to a lower five-year survival rate, often around 30%.
3. Histological Subtype: The histological subtype also influences prognosis, with germ cell tumors generally having a better outlook than epithelial tumors.

Ovarian cancer is a challenging disease with a complex pathophysiology and often late-stage diagnosis. Medical students must be aware of its epidemiology, risk factors, clinical presentation, and treatment options to provide better care to patients. Early detection through education and awareness, along with ongoing research into treatment modalities, holds promise for improving the prognosis of ovarian cancer in the future. As future healthcare professionals, medical students play a vital role in advocating for women’s health and early detection of this silent killer.

To know more about this subject, please refer various Medical Oncology textbooks like- DeVita, Hellman, and Rosenberg’s Cancer: Principles & Practice of Oncology

References:- [1] : DeVita, Hellman, and Rosenberg’s Cancer: Principles & Practice of Oncology (10th Edition)

The information in this blog has been put up from across various websites on the internet and has been modified by the author as per his understanding to a simpler language for the convenience of the reader.