AKT · Renal & urology/Urological cancer & LUTS

Renal cancer

Renal cell carcinoma (clear-cell commonest) arising from the renal tubular epithelium

Overview

Renal cell carcinoma, usually clear-cell, arising from the proximal tubular epithelium. The classic (now uncommon) triad is haematuria, flank pain and a flank mass; most are found incidentally on imaging. It is notorious for paraneoplastic syndromes and for a left varicocoele (left renal vein/IVC involvement). Localised disease is treated surgically; it is relatively chemo/radio-resistant.

Recognise

Classic triad (uncommon): visible haematuria + flank pain + palpable flank mass; often an incidental imaging finding; weight loss/fever
Paraneoplastic: polycythaemia (EPO), hypercalcaemia (PTHrP), hypertension (renin), Stauffer syndrome (deranged LFTs without mets)
A new LEFT-sided varicocoele (that doesn't empty when lying flat) → left renal vein obstruction by tumour; spreads to IVC/lung ('cannonball' metastases)

Red flags

Visible haematuria → urgent referral (NICE NG12)
Paraneoplastic hypercalcaemia/polycythaemia, IVC tumour thrombus, or a sudden left varicocoele → advanced disease work-up

Differentials & how to tell them apart

Benign renal cyst / angiomyolipomasimple cyst (no enhancement) or fat-containing AML on CT

Transitional cell carcinoma of the renal pelvisupper-tract urothelial — urine cytology/urogram

Other flank mass (polycystic kidneys)bilateral cysts + family history

Renal cell carcinoma — enhancing renal mass on contrast CT
Guite & Hinshaw et al. / CC BY 3.0 — Wikimedia Commons

Investigations

CT abdomen/pelvis with contrast (the key diagnostic/staging test — enhancing renal mass); ultrasound (incidental detection); bloods — FBC (polycythaemia), calcium, LFTs, renal function; staging CT chest; biopsy in selected cases.

Management

Nephrectomy (partial/radical) for localised disease; TKI/immunotherapy for advanced

1Characterise a renal mass on contrast CT and stage (including CT chest). Visible haematuria → urgent referral. Localised disease → partial or radical nephrectomy.Gate: Recognise the paraneoplastic clues (polycythaemia, hypercalcaemia, hypertension) and a NEW LEFT VARICOCOELE (left renal vein obstruction) as pointers to RCC/advanced disease.
2Small/unfit → active surveillance or ablation; advanced/metastatic → tyrosine kinase inhibitors or immunotherapy (RCC is relatively chemo/radio-resistant); manage paraneoplastic features.

Partial or radical nephrectomy — the mainstay for localised disease (surgery is curative; relatively chemo/radio-resistant)

Active surveillance / ablation — for small or unfit-for-surgery tumours

Tyrosine kinase inhibitors / immunotherapy — for advanced/metastatic disease (e.g. sunitinib, checkpoint inhibitors)

Manage paraneoplastic features — hypercalcaemia, polycythaemia, hypertension

Key points

Haematuria + flank pain + flank mass (classic, uncommon) or an incidental enhancing renal mass = renal cell carcinoma → contrast CT + nephrectomy for localised disease. Think RCC with paraneoplastic polycythaemia/hypercalcaemia/hypertension and a NEW LEFT VARICOCOELE; 'cannonball' lung mets.

Monitor & prognosis

Post-nephrectomy surveillance, paraneoplastic markers, metastatic disease.

Good if localised and resected; relatively treatment-resistant when metastatic (TKI/immunotherapy improving).

Source: NICE NG12 (referral); renal cancer guidance