As patients are generally asymptomatic in the early stages of disease, they tend to be diagnosed once the disease has already spread.
By Dr. Suman S Karanth
World Kidney Day 2020: Renal cell carcinoma (RCC), also referred to as Kidney cancer is a disease which arises from the renal cortex (lining of the small tubes) in the kidney. This is the most common cancer of the kidney accounting for 80 -85 percent. It is twofold more common in males and median age at diagnosis is 64 years. As patients are generally asymptomatic in the early stages of disease, they tend to be diagnosed once the disease has already spread.
World Kidney Day 2020: How do we diagnose renal cell carcinoma?
There are four stages. Stage I is diagnosed when the tumour is confined to the kidney alone and is less than 7 cm. In stage II, the tumour is still confined to the kidney however is more than 7 cm in size. In stage III, the tumour invades the layer of fatty tissue surrounding the kidney, blood vessels (renal vein or vena cava) or nearby lymph nodal structures. When the tumour involves the adrenal gland, which lies above the kidney or it spreads to other parts of the body like lungs, bones, brain or lymph nodes that are distant, then it is stage IV disease.
For adequate staging the following investigations need to performed – Imaging with abdominal computed Tomography (CT) scan and Chest X ray; and when clinically indicated Bone scan, Magnetic resonance imaging of brain and CT Chest.
World Kidney Day 2020: Key factors that determine survival rates
Here are some key factors:
1. Clinical features like fever, anemia, weight loss and poor performance status signify a poorer outcome.
2. Stage of disease at presentation – If the disease is localized in early stages of disease, the survival rates are high as opposed to when disease is at stage IV where the outcomes are poor.
3. Tumour histological subtype – The commonest sub types namely clear cell RCC accounts for 75% of the cases and has a better survival as compared to non – clear cell subtype (papillary and chromophobe type). Rarer subtypes include collecting duct carcinomas, renal medullary carcinomas and those with sarcomatoid or rhabdoid features which are very aggressive and have shorter survivals.
4. Tumour grade – The tumours are graded from Grade 1 to 4. They independently affect 5- year survivals which ranges from 89 percent in grade 1 to 46 percent in grade 3-4.
World Kidney Day 2020: Risk models available in Stage IV RCC
There are two existing risk models namely the Memorial Sloan Kettering Cancer Centre (MSKCC) prognostic Model and the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) that help determine not just the survival of these patients but most importantly to tailor treatment according to the risk group.
The Memorial Sloan Kettering Cancer Center (MSKCC) prognostic Model consists following risk factors:
1. Karnofsky Performance Status (KPS) <80.
2. Time from original diagnosis to initiation of targeted therapy being less than year.
3. Hemoglobin less than the lower limit of normal.
4. Serum calcium greater than the upper limit of normal.
5. Serum LDH levels greater than 1.5 times the upper limit of normal.
Based on this, patients are divided into 3 groups:
1. Low risk group (no risk factors),
2. Intermediate risk group (1-2 factors) and
3. High-risk group (3 or more factors).
Patients with low risk disease will benefit from oral targeted therapy with either Pazopanib or Sunitinib. Whereas, those in the intermediate and high- risk group should receive more aggressive therapy upfront with a combination of one immunotherapy with either a targeted therapy or with another immunotherapy agent.
World Kidney Day 2020: Life expectancy rates and mortality rate
Stage-wise survival rates depend additionally on type of histology and grade of tumour. Overall, 5 year – survival rates for clear cell RCC are as follows:
Stage I – Survival more than 90 percent
Stage II – between 75 to 95 percent
Stage III – between 60 to 90 percent depending on nephrectomy status and size of tumor
Stage IV – Median survival between 28 to 30 months, which varies according to risk group
To conclude, over the years, there has been a doubling of the five-year survival rate of patients, probably due to early detection of tumours at smaller sizes. Even in stage IV disease, with advent of newer targeted therapies, immunotherapy and tailoring treatment based on risk, the survival is no longer dismal.
The author is Consultant, Department of Medical Oncology, Fortis Memorial Research Institute, Gurugram. Her expertise includes treatment of all Solid malignancies and Lymphoma. She has special interest in Neuro–oncology and GI Oncology. Views expressed are the author’s own.