How is kidney cancer usually found?

Increasingly by accident. The textbook combination of flank pain, blood in the urine and a lump in the side occurs in fewer than one in ten patients and indicates advanced disease. Because CT and ultrasound scans are now performed so frequently for other reasons — abdominal pain, trauma, investigation of unrelated symptoms — more than half of kidney cancers are discovered incidentally, when they are small and confined to the kidney. This has substantially improved average outcomes. Other presentations include visible blood in the urine, unexplained weight loss or fever, anaemia, a high calcium or high haemoglobin level with no other explanation, or a new left-sided varicocele that does not empty when lying down.

Why is preserving part of the kidney so important?

Because losing a whole kidney has consequences well beyond the cancer. Removing an entire kidney for a small tumour induces chronic kidney disease in a substantial proportion of patients, and reduced kidney function is a strong independent risk factor for heart attacks, strokes and death from any cause. Since the cancer outcomes of partial and radical nephrectomy are equivalent for small tumours, taking out only the tumour and preserving the surrounding kidney gives the same cancer control with better long-term survival. This is why partial nephrectomy — or, in selected patients, ablation — is preferred wherever technically feasible, and why radical nephrectomy for a small tumour is now considered a suboptimal choice rather than a safe default.

Can a small kidney tumour just be watched?

Yes, in appropriate patients. Small renal masses under 4cm typically grow slowly, at around 3mm per year, and the risk of them spreading during a period of careful surveillance is low. Active surveillance is particularly appropriate for older patients or those with significant other illnesses, where the risks of surgery and anaesthesia may outweigh the risk from the tumour. There is a further reason: around fifteen to twenty per cent of small renal masses are not cancer at all, but benign angiomyolipomas or oncocytomas. This is why a needle biopsy of the mass — once avoided because of unfounded fears about spreading tumour along the needle track — is now recommended before ablation or surveillance, and often before surgery when the imaging is ambiguous.

How is advanced kidney cancer treated?

Kidney cancer does not respond to conventional chemotherapy, but it is unusually responsive to the immune system, and treatment has changed dramatically. The old cytokine treatments — interferon and interleukin-2 — helped few patients at the cost of severe toxicity. Targeted drugs blocking the VEGF pathway (sunitinib, pazopanib, cabozantinib, axitinib) then substantially improved outcomes. Today, first-line treatment for most patients is a combination of immunotherapies — either two checkpoint inhibitors together, or a checkpoint inhibitor combined with a targeted drug — which produce durable responses and longer survival than anything previously available. Removing the primary kidney tumour in someone who already has metastases is now a selective decision rather than routine, following the CARMENA trial.

Can kidney cancer run in families?

Yes — around five to eight per cent of cases are hereditary, and identifying this matters for the patient and their relatives. Von Hippel-Lindau syndrome causes clear cell kidney cancers that are often multiple and in both kidneys, alongside tumours of the brain, spine, retina, adrenal glands and pancreas. Hereditary leiomyomatosis and renal cell cancer causes skin and uterine fibroids together with an aggressive form of kidney cancer that needs early, decisive surgery rather than surveillance. Birt-Hogg-Dubé syndrome causes distinctive skin bumps, lung cysts and collapsed lungs alongside kidney tumours. Genetic referral is recommended for anyone diagnosed under the age of about 46, anyone with tumours in both kidneys or multiple tumours, those with a family history, and those with suggestive skin, lung or gynaecological features.

How does GMJ News cover kidney cancer?

GMJ News covers the shift to incidental detection and stage migration, partial versus radical nephrectomy and the cardiovascular consequences of nephron loss, active surveillance and renal mass biopsy for small masses, RCC subtypes and their biology, the Bosniak classification of cystic lesions, angiomyolipoma and tuberous sclerosis, ablation techniques, first-line immunotherapy combinations and IMDC risk stratification, adjuvant pembrolizumab (KEYNOTE-564), immune-related adverse events, hereditary syndromes and genetic referral criteria, and paraneoplastic presentations. Relevant to PHIG's oncology and kidney health programmes.

Home › Topics › Kidney Cancer

Kidney Cancer

GMJ News knowledge hub · last reviewed September 2026 · Georgian Medical Journal

Summary Statistics Glossary GMJ news FAQ Documents Organizations Research

Renal cell carcinoma (RCC) accounts for around 90% of kidney cancers and approximately 430,000 new cases worldwide each year, and its epidemiology has been transformed by imaging: the classical triad of flank pain, haematuria and a palpable mass is now rare, and more than half of all renal cancers are discovered incidentally on ultrasound or CT performed for unrelated reasons (WHO). This stage migration has driven two major shifts in management: nephron-sparing partial nephrectomy has replaced radical nephrectomy wherever technically feasible, because preserving renal function measurably reduces long-term cardiovascular mortality; and small renal masses under 4cm in older or comorbid patients are increasingly managed by active surveillance, since many grow slowly and a substantial minority are benign. In metastatic disease, combination immune checkpoint inhibitor regimens — alone or with tyrosine kinase inhibitors — have replaced cytokine therapy and produced durable responses previously unattainable.

Key messages

More than half of renal cancers are now found incidentally

The classical triad of flank pain, visible haematuria and a palpable mass is present in under 10% of cases and indicates advanced disease. Widespread cross-sectional imaging means over half of renal cell carcinomas are now detected incidentally on scans performed for unrelated reasons — producing stage migration towards smaller, organ-confined tumours with far better prognosis. Roughly 430,000 new cases occur worldwide annually. Risk factors: smoking, obesity, hypertension, acquired cystic disease in end-stage kidney disease, and inherited syndromes.

Partial nephrectomy wherever feasible — preserving nephrons saves lives

Nephron-sparing partial nephrectomy has replaced radical nephrectomy as the standard for T1 tumours wherever technically feasible. The rationale is not oncological — cancer outcomes are equivalent — but the recognition that removing a whole kidney induces chronic kidney disease, and CKD is a powerful independent driver of cardiovascular events and all-cause mortality. Patients undergoing radical nephrectomy for small tumours have measurably worse long-term non-cancer survival. This is a clear example of an oncological decision that must account for competing causes of death.

Small renal masses — active surveillance is legitimate, and up to 20% are benign

For small renal masses under 4cm, particularly in older or comorbid patients, active surveillance is an established option. Growth is typically slow (around 3mm per year), metastatic progression during surveillance is uncommon, and around 15-20% of small renal masses turn out to be benign lesions — angiomyolipoma or oncocytoma. Renal mass biopsy, historically avoided over unfounded fears of tract seeding, is now recommended before ablation or surveillance and increasingly before surgery in ambiguous cases, and can spare patients an unnecessary operation.

Metastatic RCC — immunotherapy combinations replaced cytokines

Metastatic renal cell carcinoma is chemotherapy-resistant but immunologically responsive. Interferon and interleukin-2 gave low response rates with severe toxicity. Targeted VEGF tyrosine kinase inhibitors (sunitinib, pazopanib, cabozantinib, axitinib) then transformed outcomes. First-line therapy is now combination immunotherapy: dual checkpoint blockade (ipilimumab plus nivolumab) or a checkpoint inhibitor combined with a TKI (pembrolizumab-axitinib, nivolumab-cabozantinib, pembrolizumab-lenvatinib), producing durable responses and improved overall survival. Risk stratification (IMDC criteria) guides regimen choice. Cytoreductive nephrectomy is now selective rather than routine following the CARMENA trial.

Hereditary syndromes — screen young patients and bilateral or multifocal disease

Around 5-8% of renal cancers are hereditary, and identification changes surveillance for the patient and the whole family. Von Hippel-Lindau: clear cell RCC (often bilateral, multifocal, young onset), CNS and retinal haemangioblastomas, phaeochromocytoma, pancreatic lesions. Hereditary leiomyomatosis and RCC (HLRCC, fumarate hydratase): cutaneous and uterine leiomyomas with an aggressive type 2 papillary RCC requiring early wide excision rather than surveillance. Birt-Hogg-Dubé (folliculin): fibrofolliculomas, lung cysts, spontaneous pneumothorax, chromophobe and hybrid oncocytic tumours. Hereditary papillary RCC (MET). Refer for genetic assessment if: age under 46, bilateral or multifocal tumours, a family history, or suggestive syndromic features.

Paraneoplastic syndromes and unusual presentations

RCC is sometimes called the internist's tumour because of its protean presentations. Paraneoplastic features: hypercalcaemia (PTHrP-mediated); polycythaemia (ectopic erythropoietin); Stauffer syndrome (non-metastatic hepatic dysfunction with raised alkaline phosphatase, reversible after nephrectomy); hypertension (renin); pyrexia of unknown origin; and AA amyloidosis. Structural presentations: a new left-sided varicocele that does not decompress on lying down, suggesting left renal vein obstruction; tumour thrombus extending into the renal vein and inferior vena cava, occasionally reaching the right atrium and requiring cardiopulmonary bypass. Any unexplained hypercalcaemia or polycythaemia warrants consideration of renal imaging.

Key statistics

~430,000

new kidney cancer cases worldwide each year; around 90% renal cell carcinoma

IARC/WHO

>50%

of renal cancers now found incidentally on imaging for unrelated reasons

EAU/AUA

15-20%

of small renal masses are benign — biopsy can spare unnecessary surgery

EAU/AUA

Partial > radical

nephron-sparing surgery preserves renal function and reduces long-term cardiovascular mortality

EAU/AUA

5-8%

of renal cancers are hereditary — refer under-46s, bilateral or multifocal disease for genetics

EAU/NCCN

IO combinations

checkpoint inhibitor combinations are first-line in metastatic RCC, replacing cytokines and TKI monotherapy

NEJM/EAU

Renal cell carcinoma — approximate 5-year survival by stage

Source: SEER/EAU. Stage migration towards incidental early detection has substantially improved aggregate survival.

Glossary of key terms

Renal cell carcinoma subtypes
Pathology/OncologyClear cell RCC (70-75%): the commonest; characterised by VHL gene inactivation with consequent HIF accumulation and VEGF overexpression — the biological basis for anti-VEGF therapy; most responsive to immunotherapy. Papillary RCC (10-15%): type 1 (often multifocal, MET-associated, generally indolent) and type 2 (more aggressive, associated with fumarate hydratase mutations in HLRCC). Chromophobe RCC (5%): generally good prognosis; associated with Birt-Hogg-Dubé. Collecting duct and renal medullary carcinoma: rare and highly aggressive — medullary carcinoma occurs almost exclusively in people with sickle cell TRAIT, an important and frequently missed association in young Black patients with a renal mass. Non-RCC kidney tumours: urothelial carcinoma of the renal pelvis (behaves like bladder cancer), Wilms tumour in children, lymphoma, sarcoma and metastases.

Bosniak classification of renal cysts
RadiologyA CT-based system stratifying cystic renal lesions by malignant potential, and one of the most useful practical tools in incidental renal findings. Category I: simple cyst, water density, thin wall, no enhancement — benign, no follow-up. Category II: minimally complex, few hairline septa, fine calcification — benign, no follow-up. Category IIF: more septa, thicker calcification, or a non-enhancing hyperdense lesion over 3cm — requires surveillance imaging, with around 5% malignancy risk. Category III: thickened, irregular, enhancing walls or septa — around 50% malignant; usually treated surgically. Category IV: clearly enhancing soft tissue components — around 90% malignant; treat as cancer. The 2019 revision refined definitions to reduce over-classification, since the commonest harm from this system is unnecessary surgery for benign complex cysts.

Angiomyolipoma
Radiology/UrologyThe commonest benign renal tumour, composed of vessels, smooth muscle and fat — diagnosed with confidence on CT by the presence of macroscopic fat (negative Hounsfield units), which effectively excludes RCC (with the rare exception of RCC containing calcification and fat). Most are sporadic, solitary and incidental. Multiple bilateral angiomyolipomas suggest TUBEROUS SCLEROSIS COMPLEX, which should prompt assessment for its other features. The clinical concern is haemorrhage: risk rises with size, and lesions above about 4cm, or those with aneurysms above 5mm, are considered for prophylactic selective arterial embolisation. Wunderlich syndrome — spontaneous retroperitoneal haemorrhage from a ruptured angiomyolipoma — is a potentially life-threatening emergency. mTOR inhibitors (everolimus, sirolimus) shrink angiomyolipomas in tuberous sclerosis.

Ablation and focal therapy
InterventionalPercutaneous radiofrequency ablation, cryoablation and microwave ablation are established options for small renal masses, particularly in older or comorbid patients, those with solitary kidneys or CKD, and in hereditary syndromes where multiple sequential tumours make repeated surgery impractical. Advantages: minimally invasive, usually day-case, excellent renal function preservation, repeatable. Limitations: slightly higher local recurrence than surgery; no definitive pathological staging — which is why pre-ablation biopsy is essential; and technical constraints for tumours near the collecting system, ureter or bowel, where hydrodissection may be used to protect adjacent structures. Follow-up relies on contrast imaging to confirm absence of enhancement in the ablated zone.

Adjuvant therapy after nephrectomy
OncologyFor decades no adjuvant therapy showed benefit — trials of TKIs after nephrectomy were largely negative (S-TRAC showed disease-free but not overall survival benefit; ASSURE and others were negative), and toxicity was substantial. The KEYNOTE-564 trial changed this, showing that adjuvant pembrolizumab after nephrectomy improved disease-free and subsequently overall survival in patients at intermediate-high or high risk of recurrence, and in those with resected metastatic disease — leading to regulatory approval. Other adjuvant immunotherapy trials have been negative, so this is not a class effect and patient selection matters. Careful risk stratification and discussion of immune-related adverse events, some of which are permanent (notably endocrinopathies), are central to the adjuvant conversation.

Immune-related adverse events
Oncology/SafetyCheckpoint inhibitors cause autoimmune toxicity that can affect any organ, and the pattern differs fundamentally from chemotherapy: onset may be delayed by months, and events can occur after treatment has stopped. Common: dermatitis, colitis, hepatitis, thyroiditis (hypothyroidism is frequently permanent), pneumonitis, arthralgia. Serious and potentially fatal: myocarditis (up to 50% mortality), hypophysitis with secondary adrenal insufficiency, severe colitis with perforation, encephalitis, myasthenic syndromes, and type 1 diabetes with ketoacidosis. Management principles: hold the drug, grade the toxicity, and give high-dose corticosteroids for grade 3-4 events, escalating to infliximab or other immunosuppression if steroid-refractory. Every patient must carry an alert card, because a patient presenting to an unfamiliar emergency department with diarrhoea, breathlessness or collapse needs the treating team to know they are on immunotherapy.