Chemotherapy in Gynecologic Oncology

Chemotherapy in Gynecologic Oncology - Chemo Agent Arsenal

• Platinum Agents: (Cisplatin, Carboplatin)
  • Mechanism: Cross-link DNA; non-cell cycle specific.
  • Backbone for ovarian, cervical, endometrial cancers.
• Taxanes: (Paclitaxel, Docetaxel)
  • Mechanism: Stabilize microtubules; M-phase specific.
  • Often combined with platinums.
• Alkylating Agents: (Cyclophosphamide, Ifosfamide)
  • Mechanism: Alkylate DNA; non-cell cycle specific.
• Antimetabolites: (Methotrexate, Gemcitabine)
  • Mechanism: Interfere with DNA/RNA synthesis; S-phase specific.
• Topoisomerase Inhibitors: (Topotecan, Etoposide)
  • Mechanism: Inhibit DNA unwinding/replication.
• Antitumor Antibiotics: (Doxorubicin, Bleomycin)
  • Mechanism: Intercalate DNA, generate free radicals.

⭐ Platinum resistance in ovarian cancer is defined as disease progression within 6 months of completing platinum-based chemotherapy.

Chemotherapy in Gynecologic Oncology - Targeted Smart Strikes

• PARP Inhibitors (Olaparib, Niraparib, Rucaparib)
  • Mechanism: Synthetic lethality in BRCA-mutated (BRCAm) / Homologous Recombination Deficiency (HRD) cells; inhibits DNA repair.
  • Uses: Ovarian Cancer (Ca) (maintenance in Platinum-Sensitive Recurrent Ovarian Cancer [PSROC], BRCAm).
  • Key Side Effects (SE): Nausea, fatigue, anemia.
• Anti-angiogenic Therapy (Bevacizumab)
  • Mechanism: Anti-VEGF-A monoclonal antibody (mAb); inhibits tumor angiogenesis.
  • Uses: Ovarian Ca (front-line with chemotherapy, recurrent); Cervical Ca (persistent/recurrent/metastatic).
  • ⚠️ Key Risks: Hypertension (HTN), proteinuria, bleeding, GI perforation, thrombosis.
• Immune Checkpoint Inhibitors (Pembrolizumab, Dostarlimab)
  • Mechanism: PD-1/PD-L1 blockade; restores T-cell anti-tumor activity.
  • Uses: Microsatellite Instability-High (MSI-H)/deficient Mismatch Repair (dMMR) Endometrial Ca; PD-L1 positive Cervical Ca.

⭐ Olaparib (a PARP inhibitor) significantly improves Progression-Free Survival (PFS) as maintenance therapy in patients with BRCA-mutated, platinum-sensitive recurrent ovarian cancer (PSROC).

Chemotherapy in Gynecologic Oncology - Cancer Battle Plans

• Core Principles:
  • Neoadjuvant: Shrink tumor pre-surgery/RT (e.g., bulky cervical).
  • Adjuvant: Post-definitive treatment (surgery/RT) to target micrometastases. Common in Epithelial Ovarian Cancer (EOC).
  • Palliative: Advanced/recurrent disease; goal is symptom control & Quality of Life (QoL).
• Key Drug Classes & Examples:
  • Platinum: Cisplatin (nephrotoxic, ototoxic), Carboplatin (myelosuppressive; Calvert formula: Dose = $Target AUC \times (GFR+25)$)
  • Taxanes: Paclitaxel (neuropathy, hypersensitivity), Docetaxel
  • Anthracyclines: Doxorubicin (cardiotoxic; for sarcomas, recurrent ovarian/endometrial)
  • Topoisomerase Inhibitors: Topotecan (2nd line ovarian/cervical)
  • Targeted Therapy:
    • Bevacizumab (Anti-VEGF; hypertension, VTE risk)
    • PARP Inhibitors (Olaparib, Niraparib for BRCAm/HRD+ EOC; GI toxicity, fatigue)

⭐ PARP inhibitors (e.g., Olaparib) significantly improve Progression-Free Survival (PFS) in BRCA-mutated ovarian cancer as maintenance therapy.

• 📌 Mnemonic for common Ovarian chemo: "CarboTax" (Carboplatin + Paclitaxel).

Chemotherapy in Gynecologic Oncology - Toxicity Damage Control

• General: Dose modification, supportive care.
• Myelosuppression:
  • Neutropenia: G-CSF. Febrile Neutropenia (FN): ANC < 500/µL + fever.
  • Anemia: ESAs, transfusions.
  • Thrombocytopenia: Transfuse if platelets < 10-20k/µL or bleeding.
• Chemotherapy-Induced Nausea & Vomiting (CINV):
  • Prophylaxis: 5-HT3 antags (Ondansetron), NK1-R antags (Aprepitant), Dexamethasone.
• Agent-Specific Toxicities & Management:
  • Cisplatin: Nephrotoxicity (hydration, Amifostine), Ototoxicity, Neurotoxicity.
  • Paclitaxel: Neurotoxicity, Myelosuppression. Premedicate for hypersensitivity.
  • Doxorubicin: Cardiotoxicity (Dexrazoxane, LVEF monitoring; max dose 450-550 mg/m²).
  • Cyclophosphamide/Ifosfamide: Hemorrhagic cystitis (MESNA, hydration).
  • Methotrexate: Myelosuppression, Mucositis (Leucovorin rescue).

⭐ Cisplatin-induced nephrotoxicity is dose-limiting; manage with hydration & Amifostine.

High‑Yield Points - ⚡ Biggest Takeaways

• Platinum agents (Cisplatin, Carboplatin) are cornerstone for epithelial ovarian cancer.
• Paclitaxel + Platinum is a standard combination for ovarian, endometrial, and cervical cancers.
• BEP regimen (Bleomycin, Etoposide, Cisplatin) is key for ovarian germ cell tumors.
• Methotrexate for low-risk GTN; EMA-CO for high-risk GTN.
• PARP inhibitors (e.g., Olaparib) are crucial for BRCA-mutated ovarian cancer.
• Bevacizumab (anti-VEGF) used for advanced/recurrent ovarian and cervical cancer.
• Key toxicities: Cisplatin (nephro/neuro/ototoxicity), Bleomycin (pulmonary fibrosis).