Ovarian Cancer for USMLE Step 3
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Ovarian Cancer for the USMLE Step 3 Exam
Ovarian Cancer
- Epidemiology:
- Ovarian cancer has the highest mortality rate among gynecologic malignancies due to frequent late-stage diagnosis.
- Risk Factors:
- Advanced age, postmenopausal status.
- Family history of ovarian or breast cancer, particularly with BRCA1 or BRCA2 mutations.
- Hereditary nonpolyposis colorectal cancer (Lynch syndrome) also increases risk.
- Increased ovulatory cycles (e.g., nulliparity, early menarche, late menopause).
- Protective Factors:
- Oral contraceptive use, pregnancy, and breastfeeding, all of which reduce ovulatory cycles.
Types of Ovarian Cancer
- Epithelial Tumors:
- Comprise about 90% of ovarian cancers, most commonly serous carcinoma.
- Serous Carcinomas: Most aggressive, often presenting at advanced stages.
- Mucinous Carcinomas: Less common; can grow large.
- Endometrioid and Clear Cell Carcinomas: Frequently associated with endometriosis.
- High-Grade vs. Low-Grade Serous Carcinomas: High-grade serous carcinoma is more aggressive and has a poorer prognosis.
- Germ Cell Tumors:
- Arise from ovarian germ cells, typically affecting younger women.
- Includes dysgerminomas, yolk sac tumors, and immature teratomas.
- Generally chemosensitive and have a good prognosis with treatment.
- Sex Cord-Stromal Tumors:
- Originate from ovarian stromal cells, sometimes producing hormones.
- Granulosa Cell Tumors: Produce estrogen, potentially causing symptoms like endometrial hyperplasia or precocious puberty.
- Sertoli-Leydig Cell Tumors: Produce androgens, leading to virilization in women.
Clinical Presentation
- Symptoms:
- Early-stage ovarian cancer is often asymptomatic, while advanced stages may cause:
- Abdominal bloating or distension.
- Pelvic pain or pressure.
- Early satiety or loss of appetite.
- Urinary urgency or frequency.
- Advanced Disease: Ascites, bowel obstruction, and pleural effusion may occur.
- Physical Exam:
- May reveal a palpable abdominal or pelvic mass, ascites, or evidence of pleural effusion if metastasis is present.
Diagnosis
- Imaging:
- Pelvic Ultrasound: First-line imaging for adnexal masses.
- Malignant features include thick septations, solid components, papillary projections, and presence of ascites.
- CT Scan: Used for staging and evaluating metastasis.
- Laboratory Tests:
- CA-125: Tumor marker often elevated in epithelial ovarian cancers but not specific, as it can be elevated in benign conditions.
- Other Tumor Markers:
- AFP, hCG, and LDH: Useful for identifying specific germ cell tumors.
- Inhibin and Estradiol: Elevated in granulosa cell tumors.
- Histopathology:
- Definitive diagnosis is obtained through histologic examination of a biopsy or surgical specimen.
Staging
- FIGO Staging:
- Stage I: Confined to ovaries.
- Stage II: Spread to 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: Mainstay of treatment for advanced disease, involving removal of ovaries, fallopian tubes, uterus, omentum, and any visible tumor.
- Fertility-Sparing Surgery: May be considered in early-stage disease for young patients desiring fertility preservation.
- Chemotherapy:
- Platinum-Based Chemotherapy: Typically carboplatin and paclitaxel for epithelial ovarian cancer.
- Germ Cell Tumors: Treated with BEP regimen (bleomycin, etoposide, and cisplatin), with favorable outcomes.
- Targeted Therapy:
- PARP Inhibitors: Effective in BRCA-mutated ovarian cancer, prolonging progression-free survival.
- Bevacizumab: An anti-VEGF monoclonal antibody used to inhibit angiogenesis in advanced disease.
Key Points
- Ovarian Cancer is often diagnosed at advanced stages; epithelial tumors are the most common type.
- Risk Factors include age, genetic mutations (e.g., BRCA1/BRCA2), and increased ovulatory cycles, while protective factors include oral contraceptives and pregnancy.
- Diagnosis uses ultrasound imaging and CA-125 marker evaluation, with histopathology for definitive diagnosis.
- Staging follows the FIGO system, with prognosis declining in advanced stages.
- Treatment includes debulking surgery and chemotherapy, with targeted therapies like PARP inhibitors and bevacizumab for specific cases.