What are Kidney tumors?
Kidney tumors are a diverse group of tumors which can range from simple benign lesions like Oncocytoma which are harmless to frankly malignant lesions like Renal cell carcinoma which may be life threatening. The benign tumors grow very slowly and rarely is life threatening unlike the malignant tumors, which grow rapidly, and is life threatening.
What are the types of Kidney tumors?
There are multiple types of kidney tumors. The most common type among adults being Renal cell carcinoma (Adenocarcinoma), which constitutes almost 90-95% cases, followed by Transitional cell carcinoma.
Other rare tumors are Oncocytoma, angiomyolipoma, squamous cell carcinoma, sarcoma, etc.
Where do they arise?
Kidney consists of many parts like kidney cells, blood vessels, urine collecting system and tumors may arise from any of the various parts. The most common type of tumors arising from the kidney cells is the renal cell carcinoma (RCC).
However another commonly occurring cancers are Transitional cell carcinoma (TCC) arising from urine collecting system.
Other types may arise form blood vessels, fat or soft tissue etc.
What are the signs & symptoms?
Most of the kidney tumors in todays era are asymptomatic (i.e. have no symptoms) as they are mostly detected by chance on Ultrasound, CT scan or MRI done for some other unrelated reasons, so much so that these tumors are also known as the Radiologist/Doctor’s tumors.
The most common symptoms usually are flank pain, blood in urine or in later stages abdominal mass. Sometimes they can present with fever, weight loss, or generalized weakness. When the disease has spread beyond the kidneys, patients can develop lower limb swelling, backache, headache, cough etc.
Those who develop TCC of kidneys might present with blood in urine as the first and the only symptom with or without other non-specific symptoms like generalized weakness, fever.
Who are likely to develop these tumors?
Most of the kidney cancers, mainly RCC develop sporadically i.e. without any family history of such tumors. However around 10-15% of tumors can be familial which occur due to some genetic alterations which are transmitted in families.
People who have high blood pressure, or who consume tobacco or those who are too fat, are at increased risk of developing these tumors.
People who suffer from stone disease or are undergoing chronic dialysis for renal failure are also at increased risk of developing these tumors.
How can it be diagnosed?
As mentioned previously most of these tumors in today’s era are incidentally detected on imaging such as ultrasound or CT scan performed for some or the other reasons.
Apart from CT scan or MRI, Chest x ray and certain blood tests which include Complete blood counts, Kidney function, Liver function tests, urine tests are done.
Those having any abnormality in liver function tests or complaining of bony pains undergo bone scan to detect spread of tumors to bone.
There is no role of FDG-PET scan in diagnosis of these tumors, however they are sometimes used for detection of recurrences.
What is the treatment for Kidney cancers?
Treatment is largely dependent upon the type of kidney tumor as well the stage of the tumor (extent of disease spread). For the most common variety “RCC”, if the opposite uninvolved kidney is normal, and there are no comorbidities like high blood pressure or Diabetes or any preexisting kidney disease, complete removal of the tumor-bearing kidney is the standard treatment, which is known, in medical terminology as Radical Nephrectomy.
However in patients who have a single kidney (either by birth or due to previous surgery) or in patients with Diabetes or high blood pressure or chronic kidney disease, or in patients with tumor in both the kidneys, only tumor along with rim of normal tissue is removed, with preservation of normal kidney, known as Partial nephrectomy. Now a day, partial nephrectomy has become a standard of care if tumour is around 5-6 cm in a kidney. These tumors are removes with 1 cm margins of normal kidney tissue and kidney is repaired and saved. Advantage is preservation of kidney function, which is very important for our life.
Certain patients with kidney tumors have a portion of tumor entering big vessels (renal vein &/or Inferior vena cava), which open, into heart. This group constitutes approximately 10% and requires expert care and management at a tertiary center.
For patients whose tumors have progressed beyond the kidneys into other distant sites like, lung, liver, bones, brain etc. and if they are fit enough to undergo the surgery, radical nephrectomy (in this situation called as “ Cytoreductive nephrectomy ”) is performed. The other metastatic sites can also be removed surgically if feasible.
Treatment of TCC of kidneys is however different from that of RCC. In this the kidneys along with the ureter (tubular structure which transmits urine from kidney to urinary bladder) and 1 cm bladder cuff has to be removed in high-grade lesions, whereas for low-grade tumors, simple endoscopic fulguration and BCG instillations suffice.
What are the medicines given once the kidney is removed in Metastatic disease?
Once these patients have recovered from the surgery, a special type of anticancer medicines is started known as TKI’s (Tyrosine Kinase inhibitors) e.g. sunitinib, sorafenib, pazopanib etc. Currently newer immunotherapeutic medicines are also available both as injectable and as oral medicines, e.g. Temisirolimus, Everolimus, Nivolumab, Cabozanitinib etc. These medicines are known to shrink the metastatic tumor deposits and prolong disease progression but they do not cure the disease.
Is there any treatment if patient is not fit to undergo surgery?
In certain elderly patients with small peripherally located tumors who are not surgically fit, newer technologies which involve killing the tumor cells either by heat e.g. Radiofrequency ablation (RFA), Microwave therapy or by cooling e.g. cryoablation are available at selected centers and can be dealt with safely, however due to its limited availability, high cost, poor reproducibility and unavailability of expertise, and the psychological fear of leaving behind the tumor in the body, these modality are not routinely used at least in India.
What are the different approaches of kidney surgery?
Surgery for kidney cancers is performed by large open incisions, laparoscopically or robotically. Open surgeries are mainly performed in cases with large tumors more than 12 cm size or invading adjacent organs or associated with clot in big blood vessels or if doing partial Nephrectomy in patients with a single kidney. Gradually open surgeries are becoming historic as with the advancements in instrumentation, technology and expertise, laparoscopy has overshadowed open surgery, the main advantages being its minimally invasive nature, key hole surgery, less pain, faster recovery and discharge from hospital and fewer complications. Now a day most of the kidney surgery is done laparoscopically.
Going one step ahead, Robotics has further revolutionized the management of kidney cancers, mainly in performing Partial nephrectomies because of its precision and efficient suturing advantages apart from the usual advantages of laparoscopy. Now a day most of partial nephrectomies are done robotically with excellent outcome. Its only disadvantage is its cost, which is 1.25 lakhs extra.
Is there a role of Radiotherapy or chemotherapy in kidney cancers?
There is a very limited role of Radiotherapy in the treatment of RCC as these tumors are resistant to radiotherapy.
Radiotherapy may however be used as a palliation (symptomatic relief) to decrease severe bony pains or refractory bleeding from urine collecting system.
As far as chemotherapy is concerned, certain subtypes of RCC, like collecting duct tumors, Bellini duct tumore and sarcomatoid differentiation, have been shown to have a some beneficial effect, however is still investigational.
Chemotherapy also has a role in TCC of kidney after nephrectomy has been done.
On the other hand chemotherapy has good response in the treatment of childhood Wilms tumors.
For patients with Severe bony pains arising due to metastasis to bones from kidney tumors, local radiotherapy can be given as a palliation.
How is the follow up done after surgery?
Usually after surgery patients are discharged around 3-4 days later and called for OPD visit around 1 week from discharge. Initially they are followed up at 3 months, then 6 months and then annually thereafter at least till 5 yrs., and preferably lifelong at increasing intervals. Tumors can recur even years later, but usually recur within first 2 years. During these visits they undergo a detailed clinical history and physical examination along with blood tests, chest x rays and contrast CT scan or MRI of abdomen and some other tests if required.
Whereas follow up after surgery for TCC of kidney is slightly different in that apart from the tests mentioned above, urine cytology (to look for cancer cells,) & cystoscopy (endoscopy of urinary bladder) also needs to be performed at regular intervals to detect recurrences early.
What is the survival rate of kidney cancers?
Survival rate of patients with kidney tumors is stage dependent. For RCC, which are localized to the kidneys, the 5-year survival rate is greater than 90%, however for tumors, which have spread beyond the kidneys to surrounding fat, the survival is around 60%. Survival decreases further to 10-20% as the spread occurs to lymph nodes or distant sites.
Survival for TCC of kidney is much poorer than RCC and ranges from 50-60%.
Survival rates for other varieties of kidney tumor are worse than above.
Can it be prevented?
In todays era of stressful life, leading a healthy lifestyle and avoiding the risk factors mentioned above, does not guarantee against developing a kidney cancer. So these tumors are not 100% preventable, but leading a healthy lifestyle is in general beneficial for an individual and as a whole reduces the chances of other infections and cancers.
Moreover certain tumors are hereditary and cannot be prevented at present.
So regular health check ups and early detection is the key to successful treatment and good long-term outcomes.
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