Renal Cell Carcinoma

RCC: Intro & Epidemiology - Kidney Chaos Kickoff

• Renal Cell Carcinoma (RCC): Most common primary renal malignancy (~90%).
• Origin: Renal tubular epithelium.
• Peak incidence: 60-70 years; M:F ratio ~ 2:1.
• Risk Factors:
  • Smoking (doubles risk 🚬).
  • Obesity & Hypertension.
  • Chronic kidney disease & dialysis.
  • Genetic syndromes (e.g., von Hippel-Lindau, Birt-Hogg-Dubé).
  • Analgesic nephropathy.
• Common Histological Subtypes:
  • Clear Cell RCC (70-80%): Most common, often VHL gene mutation.
  • Papillary RCC (10-15%).
  • Chromophobe RCC (5%).

⭐ Most significant modifiable risk factor for RCC is cigarette smoking. Quitting smoking can reduce the risk over time.

📌 RCC Risk Factors (S.H.O.C.K.S.): Smoking, Hypertension, Obesity, Chronic Kidney Disease, Known Genetic Syndromes, Sex (Male).

RCC: Pathogenesis & Histology - Cellular Crime Scene

• Pathogenesis:
  • VHL gene (Chr 3p) inactivation: Central to Clear Cell RCC (ccRCC).
    • ↑HIF → ↑VEGF, PDGF → angiogenesis, growth.
  • Hereditary: VHL disease. Sporadic: Most common.
  • Other genes: MET (Papillary), FH, BAP1, PBRM1.
• Histological Subtypes:
  • Clear Cell (ccRCC, ~75%):
    • Clear cytoplasm (glycogen, lipids); rich vasculature.
    • 
  • Papillary (PRCC, ~15%):
    • Papillae, foamy histiocytes. MET (Type 1), FH mutations.
  • Chromophobe (ChRCC, ~5%):
    • Pale cells, prominent membranes ("plant-like"), perinuclear halos. Hale's colloidal iron+.
  • Collecting Duct/Medullary: Rare, aggressive.

⭐ Most RCCs are Clear Cell type (~75%), characterized by VHL gene loss on chromosome 3p, leading to HIF pathway activation.

RCC: Clinical Features & Diagnosis - Spotting the Signs

• Classic Triad (6-10%): Hematuria, flank pain, palpable mass.
  • Most common: Incidental finding on imaging (>50%).
• Systemic: Fever, weight loss, night sweats.
• Paraneoplastic (≈30%):
  • Hypercalcemia (PTHrP)
  • Polycythemia (EPO ↑)
  • Hypertension (Renin ↑)
  • Stauffer's (hepatic dysfunction)
  • Anemia
• Local: Acute varicocele (L-sided, non-reducing).
• Mets: Bone pain, cough, nodes.

Diagnostic Pathway:

• Imaging:
  • USG: Initial, solid vs. cystic.
  • CECT Abd/Pelvis: IoC for Dx & staging. Defines mass, local/vascular extent, nodes.
  • MRI: CECT C/I or equivocal (thrombus).
  • Staging adjuncts: CT Chest, Bone Scan (Sx/↑ALP).
• Labs: Urinalysis (hematuria), CBC, LFT, RFT, $Ca^{2+}$, LDH.
• Biopsy (Image-guided):
  • Generally NOT for resectable solid masses.
  • Indications: Mets Dx pre-systemic Rx; small masses (<4cm) for active surveillance/ablation.

⭐ > Over half of RCCs are detected incidentally during imaging for other conditions, often asymptomatic.

RCC: Management & Prognosis - The Treatment Blueprint

• Localized RCC (T1-T2, N0, M0):
  • Partial Nephrectomy (PN): Preferred for T1a; feasible for T1b, selected T2. Preserves renal function.
  • Radical Nephrectomy (RN): For larger tumors or when PN not feasible.
  • Ablative therapies (cryoablation, RFA): For small renal masses (<3 cm) in non-surgical candidates.
• Locally Advanced RCC (T3-T4, N0-1, M0):
  • RN +/- regional lymphadenectomy.
  • Adjuvant immunotherapy (e.g., pembrolizumab) for high-risk clear cell RCC post-nephrectomy.
• Metastatic RCC (M1):
  • Cytoreductive Nephrectomy: In select patients with good performance status before systemic therapy.
  • Systemic Therapy: Immune checkpoint inhibitors (ICI) +/- tyrosine kinase inhibitors (TKI) are first-line (e.g., ipilimumab + nivolumab; pembrolizumab + axitinib).

• Prognostic Factors:
  • Stage (TNM), Fuhrman/ISUP grade, tumor necrosis, sarcomatoid features.
  • Performance status (Karnofsky/ECOG).
  • Lab: ↑LDH, ↑Ca, ↓Hb.

⭐ For metastatic clear cell RCC, the combination of an immune checkpoint inhibitor and a VEGF TKI (e.g., pembrolizumab + axitinib) is a common first-line treatment, significantly improving progression-free survival compared to sunitinib monotherapy.

• Follow-up: Risk-stratified; imaging (CT/MRI) and labs. Recurrence commonest in first 2-3 years. 📌 Mnemonic (Prognosis - BAD): Bone mets, Anemia, Disease-free interval <1yr, ↑LDH, ↑Ca, Karnofsky <80% (IMDC criteria components).

High‑Yield Points - ⚡ Biggest Takeaways

• Clear cell carcinoma is the most common RCC subtype.
• Classic triad (hematuria, pain, mass) is rare (~10%); often an incidental finding on imaging.
• Paraneoplastic syndromes (polycythemia, hypercalcemia, hypertension) are common.
• Key risk factors: smoking, obesity, and Von Hippel-Lindau (VHL) syndrome.
• Radical nephrectomy is curative for localized RCC; it's radioresistant and chemoresistant.
• Lungs are the most common metastatic site (characteristic cannonball metastases).