Renal Tumours & Nephrolithiasis: Year 2 Surgery

• The title of the presentation is ‘Renal Tumours and Nephrolithiasis’, for Year 2 Surgery students in 2023-2024.

Learning Objectives

• Describe the epidemiology and aetiology of kidney neoplasms and urolithiasis
• List the classification of kidney neoplasms
• Explain the clinical manifestations of kidney neoplasms and urolithiasis
• Discuss staging and grading of kidney neoplasms
• Discuss the management plan and treatment options

Renal Cancer/Renal Cell Cancer

• Kidney Cancer is the 10th most common cancer and 3% of all adult malignancies.
• It is adenocarcinoma of the renal cortex, possibly from proximal convoluted tubule, and often asymptomatic in 50% of cases.
• There are high rates of incidental diagnosis due to radiology.
• Renal cell cancer is the most lethal urological cancer with 50% of patients dying from RCC and only a 50% overall 5-year survival rate.
• At the time of presentation, 20-30% have metastasized, while metastatic RCC at the time of diagnosis has a 5-year survival rate of less than 10%.
• It is more common in men (2:1) with a peak incidence between 60-70 years of age.
• Risk factors include: smoking, renal failure, dialysis, obesity, and hypertension.
• In Von Hippel-Lindau (VHL) syndrome, 50% of autosomal dominant patients will develop RCC; familial syndromes all autosomal dominant includes 3p25(VHL), 7q34(Hereditary Paillary RCC), 17p11.2 (Birt-Hogg-Dubé), 1q42 (Hereditary Leiomyoma RCC).

Aetiology

• Tobacco (increases relative risk x1.4-2.5)
• There is a 10-20% higher incidence in African Americans.
• Acquired renal cystic disease affects 1/3 of patients; patients develop ARCD after 3 years of dialysis for chronic kidney disease, yielding a 3-6 times higher risk of developing RCC.
• Nutrition: asian migrants to western countries are at increased risk
• Obesity, low SE class, asbestos, and hypertension are associated.

Renal cell carcinoma classification

• Histological Subtypes Include:
  • Clear cell carcinoma (80%)
  • Papillary carcinoma (10-15%)
  • Chromophobe carcinoma (5%)
  • Collecting Duct/Bellini (rare)
  • Medullary cell cancer (rare)
• Sarcomatoid variant is infiltrative and poorly differentiated
• Eosinophilic variant has a higher risk of progression.
• Clear cell RCC can be determined using Fuhrman Grading, where 1 is well differentiated, 2 is moderately differentiated, and 3,4 is poorly differentiated.

Symptoms

• RCC is an incidental finding on imaging in 50% of cases, but may show the classic triad: pain, mass, and haematuria.
• Haematuria may be gross or microscopic
• Metastatic disease results in bone pain, haemoptysis, and oedema.
• Rapidly developing left sided varicocele may be an indication

Paraneoplastic Syndrome (10-40%)

• Polycythaemia ( excess erythropoietin)
• Iron deficiency anaemia
• Hypertension ( excess renin production, renal artery compression)
• Hypercalcaemia 10-20% (due to production of parathyroid-like hormone)
• Pyrexia of unknown origin
• Elevated ESR
• Cushing's (ectopic secretion of ACTH)
• Stauffer's syndrome (Hepatic dysfunction, fever, anorexia)

Differential Diagnosis for Renal Masses

• Cystic vs solid masses
• Simple Cysts include cysts, parapelvic cysts, and calyceal diverticulae
• Complex Cysts include renal carcinoma, cystic nephroma, haemorrhagic cysts, metastasis, Wilms Cyst, Lymphoma, TB, and renal artery aneurysm.
• Fatty Masses include angiomyolipoma, lipoma, and liposarcoma.
• Other differentials include Renal Cell Cancer, Metastasis, Lymphoma, Sarcoma, TB, XPG, Phaeochomocytoma, and Upper Tract TCC
• Classification of Renal cysts is done using the Bosniak classification for CT scans.
  • Category 1: Uncomplicated simple cyst, no follow-up is required.
  • Category 2: Minimally complicated cysts with hairline-thin septa that are never malignant
  • Category 2F: Minimally complicated, minimal enhancement, follow-up required
  • Category 3: Complicated cysts, thickened irregular walls, 50% malignant
  • Category 4: Large irregular cyst with solid internal components, enhancing soft-tissue components, nearly always malignant

Staging and Investigations

• Ultrasound is the usual first-line investigation that can be performed.
• Computer Tomography (CT) will assist with contrast enhancement
• Magnetic Resonance Imaging (MRI) is used to investigate IVC, locally advanced disease, renal insufficiency.
• A percutaneous renal biopsy to select patients with small renal masses for surveillance approaches, to obtain histology before ablative treatments, or to select the most suitable form of targeted pharmacologic therapy in the setting of metastatic disease.

Staging TNM

• T1 confined to kidney ≤7cm, including T1a ≤4cm and T1b 4cm and ≤7cm
• T2 confined to kidney >7cm
• T3 locally advanced within Gerota's fascia, including T3a adrenal and/or perinephric fat, T3b renal vein or IVC below diaphragm, T3c IVC above diaphragm
• T4: invades beyond Gerota's fascia
• N0 no regional lymph node involvement
• N1 mets in single node
• N2 mets in more than one node
• M0 no distant mets
• M1 distant mets
• Metastatic Spread involves the invasion of surrounding structures.
• Vascular invasion is associated with thrombosis.
• The renal Vein, IVC, and Atrium may be affected.
• Common sites of distant metastases are the lungs(cannonball metastases), bone, liver, adrenal, and cerebral/CNS.

Treatment Options

• Surgical treatment is the mainstay of treatment for RCC.

Radical Nephrectomy

• The gold standard for T2-4 tumors (>7cm) and T1 RCC patients unsuitable for PN
• Laparoscopic approach preferred
• Open approach employed for large or locally advanced tumours
• Surgical Method invloves Renal mobilisation, Identification and ligation of ureter, and Clamping of renal artery then renal vein (prevents renal swelling)

Partial Nephrectomy

• Gold standard for localised disease and preserves as much kidney as possible.
• It is an absolute indication in single kidney/ bilateral tumours
• Stage 3 chronic kidney disease (CKD) is more common after radical nephrectomy than partial nephrectomy (PN).
• Overall survival appears better with PN
• Multiple modalities exist with open, laparoscopic, and robotic options.
• The procedure requires temporary clamping of vessels.
• An open procedure is faster (≈150mins) and cheaper but longer LOS, with more blood loss.
• The robotic approach is better than laparoscopic, yields better GFRs and warm ischaemic time as well as a shorter LOS.

Treatment for Localized RCC

• Active Surveillance for small renal masses in elderly/unfit patients
• Cyst growth rate can be slow (less than 0.3cm/y)
• Metastases are rare in tumours smaller than 3cm.
• Renal Artery Embolisation is used for the management of symptomatic haematuria
• Percutaneous radiofrequency ablation/cryotherapy
• Stereotactic radiotherapy (clinical trial only)

Treatment for Metastatic RCC

• 25% of patients have metastatic RCC at presentation and 30% will develop it in follow-up.
• Chemotherapy has little role in RCC
• Immunotherapy: VEGF is overexpressed in most sporadic RCCs and RCCs are highly angiogenic.
  • Treatments include Tyrosine Kinase Inhibitors (Sunitinib, Pazopanib), Immune checkpoint inhibitors (Nivolumab). and mTOR Inhibitors (Everolimus).
• Cytoreductive Nephrectomy confers 10-month survival in patients prior to systemic immunotherapy; recent trials have disputed this fact (CARMENA trial).
• Metastatectomy may have benefit in solitary mets.

Urolithiasis

• Kidney stones are more common in males ages 20-50 years of age.
• The majority of urinary tract stones are radiopaque, and Calcium stones represent 75% of all urinary tract stones.
• Staghorn calculi(calcium phosphate, ammonium, and magnesium constitute 15% of all urinary tract stones and are commonly seen with recurrent UTIs.
• Uric acid stones and cysteine stones are also common.

Aetiology and Risk factors

• Dehydration
• Hyperparathyroidism
• Idiopathic hypercalciuria
• Familial metabolic causes, eg. Cystinuria

Clinical Manifestations

• The main symptoms are a sudden onset of severe, stabbing, intermittent loin-to-groin pain, nausea, vomiting, fever, and tachycardia.
• Rarely will macroscopic haematuria be present
• Signs: Pyreia and renal angle tenderness

Investigations

• Bedside investigations include a urine dipstick and bHCG to rule out pregnancy
• Laboratory findings include: FBC (raised WCC and Hb), U&E, CRP, Serum corrected calcium, Phosphate and uric acid levels, Parathyroid hormone.
• Imaging can be done with Xray KUB(kidney, ureter and bladder), Non-contrast CT KUB ,or Non-contrast MRI in pregnancy.

Management

• Analgesia
• Anti-emetic
• Hydration
• Alpha blocker eg. Tamsulosin
• Definitive treatment: ESWL (extracorporeal shock wave lithotripsy), Flexible ureteroscopy to retrieve stone, PCNL (percutaneous nephrolithotomy), Open nephrolithotomy