Watch: the CureRays® explainer series
Prefer to read? The full guide below is complete on its own, with tables you can revisit any time.
What is kidney cancer?
The kidneys are two bean-shaped organs that filter waste from the blood into urine. Kidney cancer usually begins in the tiny tubes that do this filtering. Because early kidney cancer rarely causes symptoms, many tumors are discovered by accident when a scan is done for another reason — and at that stage they are often small and curable. Kidney cancer has long been considered resistant to ordinary radiation, but modern high-precision stereotactic radiation is changing that for patients who cannot have surgery.
The main types
Doctors group kidney cancer by where it starts and how it behaves:
| Type | What it means, simply |
|---|---|
| Clear cell renal cell carcinoma | The most common type, about 7 in 10 cases; named for how the cells look under the microscope. |
| Papillary & chromophobe RCC | Less common renal cell subtypes that often behave somewhat more gently. |
| Other types | Rarer cancers including transitional cell (in the kidney's collecting area) and, in children, Wilms tumor. |
Staging, in plain terms
Staging uses T (tumor size and whether it stays within the kidney), N (lymph nodes involved), and M (metastasis/distant spread). Size and whether the cancer has grown beyond the kidney are the biggest factors.
| TNM | What it generally means |
|---|---|
| Stage I | Tumor 7 cm or smaller, confined to the kidney. Usually cured by removing the tumor or, when needed, treated with focused radiation. |
| Stage II | A larger tumor (over 7 cm) but still confined to the kidney. |
| Stage III | Spread into nearby tissue, a major vein, or lymph nodes, but not to distant organs. |
| Stage IV | Spread beyond the kidney area to distant organs. Treated with modern medicines that can control it well, sometimes combined with targeted radiation. |
The standard of care
Kidney Cancer is almost always treated by a team that may include a surgeon, a medical oncologist, and a radiation oncologist, combining therapies for the best result. The usual building blocks are:
Surgery
The main curative treatment — removing just the tumor (partial nephrectomy) when possible to preserve kidney function, or the whole kidney for larger tumors.
Active surveillance / ablation
Small, slow-growing tumors in older or frail patients may be watched closely or treated with heat or cold (ablation) instead of surgery.
Systemic medicine & SBRT
For advanced disease, immunotherapy combinations and targeted drugs are standard; stereotactic radiation can ablate the primary tumor in non-surgical patients or control limited spread.
How radiation treatment works
Radiation uses focused high-energy x-rays to damage cancer-cell DNA so the cells can no longer divide. Kidney cancer was long thought to resist radiation, but stereotactic body radiation therapy delivers a much larger dose per session, with image guidance and breath-motion management keeping the beams locked on the tumor while sparing the rest of the kidney and nearby organs. Treatments are painless and brief; side effects are usually mild, such as temporary fatigue or nausea, and most kidney function is preserved.
The main ways radiation is delivered for kidney cancer:
Stereotactic body radiation therapy (SBRT)
Delivers a few very high, precise doses that overcome kidney cancer's usual radiation resistance, controlling the primary tumor in over 90% of cases for patients who cannot have surgery.
SBRT for oligometastases
Focused radiation can ablate a small number of spots where kidney cancer has spread — to bone, lung, or elsewhere — often delaying the need to change drug therapy.
Palliative radiation
Short courses relieve pain or other symptoms from kidney cancer that has spread, especially to bone.
Latest studies shaping care
Care keeps improving — often toward getting the same excellent results with less burden on patients. A few developments:
SBRT for inoperable kidney cancer (FASTRACK II): A prospective trial showed stereotactic radiation achieved excellent local control with preserved kidney function for primary kidney cancers in patients unfit for surgery.[1]
FASTRACK II / TROG
Immunotherapy combinations as standard: Pairing immunotherapy with targeted drugs has become the standard first treatment for advanced kidney cancer, substantially improving survival.[2]
CheckMate 9ER, KEYNOTE-426
Radiation plus immunotherapy: Studies are exploring whether SBRT can boost the immune response to checkpoint drugs, potentially improving control of metastatic kidney cancer.[3]
Ongoing RCC SBRT-immunotherapy trials
Common questions
My kidney tumor was found by accident — is that bad? Often it is actually good news. Incidentally found kidney cancers tend to be small and early, when cure rates are highest.
I heard radiation doesn't work on kidney cancer — is that still true? That was the old view with conventional radiation. Modern stereotactic radiation (SBRT) uses much higher, focused doses that effectively control kidney tumors, and it is a real option when surgery is not.
Will I be able to live with one kidney? Yes. Most people function normally with one healthy kidney, which is why surgeons preserve as much kidney as possible whenever they can.
References
Numbered sources for the studies cited above. Links open the primary publication on PubMed or the publisher’s site.