Ovarian Cancer for USMLE Step 2
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Ovarian Cancer for the USMLE Step 2 Exam
Ovarian Cancer
- Epidemiology:
- Ovarian cancer is a leading cause of death among gynecologic cancers due to late-stage diagnosis.
- Risk Factors:
- Advanced age, especially postmenopausal women aged 50–70.
- Family history of ovarian or breast cancer, especially with BRCA1 or BRCA2 mutations.
- Lynch syndrome (hereditary nonpolyposis colorectal cancer) also increases the risk.
- Increased lifetime ovulatory cycles (e.g., nulliparity, early menarche, late menopause).
- Protective Factors:
- Oral contraceptives, pregnancy, and breastfeeding, which reduce the frequency of ovulation.
Types of Ovarian Cancer
- Epithelial Tumors:
- Account for about 90% of ovarian cancers, classified by cell type:
- Serous Carcinomas: Most common, aggressive, and often diagnosed at advanced stages.
- Mucinous Carcinomas: Rare, can grow large and are typically unilateral.
- Endometrioid and Clear Cell Carcinomas: Often associated with endometriosis.
- High-Grade vs. Low-Grade Serous Carcinomas: High-grade serous carcinoma is more aggressive, often with poor prognosis.
- Germ Cell Tumors:
- Primarily affect younger women, generally have good prognosis with treatment.
- Includes dysgerminomas, yolk sac tumors, and immature teratomas.
- Sex Cord-Stromal Tumors:
- Arise from stromal cells, producing hormones.
- Granulosa Cell Tumors: Produce estrogen, causing symptoms like endometrial hyperplasia.
- Sertoli-Leydig Cell Tumors: Produce androgens, which may cause virilization.
Clinical Presentation
- Symptoms:
- Early stages often asymptomatic. Advanced disease symptoms include:
- Abdominal bloating and distension.
- Pelvic pain or pressure.
- Early satiety and loss of appetite.
- Urinary urgency or frequency.
- Advanced Disease: Ascites, bowel obstruction, or pleural effusion may occur.
- Physical Exam Findings:
- May reveal a palpable pelvic mass, abdominal distension, or ascites in advanced cases.
Diagnosis
- Imaging:
- Pelvic Ultrasound: First-line imaging for adnexal masses.
- Malignant features include thick septations, solid areas, papillary projections, and ascites.
- CT Scan of the Abdomen and Pelvis: Used for staging and to assess metastatic disease.
- Laboratory Tests:
- CA-125: Often elevated in epithelial ovarian cancers but nonspecific, as it can also be elevated in benign conditions.
- Other Tumor Markers:
- AFP, hCG, and LDH: Useful in diagnosing specific germ cell tumors.
- Inhibin and Estradiol: Often elevated in granulosa cell tumors.
- Histopathology:
- Definitive diagnosis is obtained through histologic examination of biopsy or surgical specimens.
Staging
- FIGO Staging:
- Stage I: Confined to the ovaries.
- Stage II: Involves pelvic organs.
- Stage III: Spread to abdominal organs or lymph nodes.
- Stage IV: Distant metastasis (e.g., liver, pleural effusion).
Treatment
- Surgical Treatment:
- Debulking Surgery: Standard for advanced epithelial cancers, involving removal of ovaries, uterus, fallopian tubes, omentum, and any visible tumor.
- Fertility-Sparing Surgery: Considered in early-stage disease for young patients desiring fertility.
- Chemotherapy:
- Platinum-Based Chemotherapy: Mainstay treatment, usually carboplatin and paclitaxel for epithelial cancers.
- Germ Cell Tumors: Responsive to BEP regimen (bleomycin, etoposide, and cisplatin).
- Targeted Therapy:
- PARP Inhibitors: Effective in BRCA-mutated and homologous recombination-deficient cancers.
- Bevacizumab: An anti-VEGF monoclonal antibody used in advanced stages to inhibit angiogenesis.
Key Points
- Ovarian Cancer has a high mortality rate, with epithelial tumors as the most common type, often diagnosed at an advanced stage.
- Risk Factors include age, family history, and genetic mutations (e.g., BRCA1/BRCA2), while protective factors include oral contraceptives and pregnancy.
- Diagnosis involves ultrasound imaging and CA-125 marker evaluation, with histopathology required for confirmation.
- Staging follows the FIGO system; prognosis worsens significantly at later stages.
- Treatment includes debulking surgery and chemotherapy, with targeted therapy (PARP inhibitors and bevacizumab) in advanced or recurrent disease.