Renal Medullary Carcinoma (RMC) is a very rare form of kidney cancer that primarily affects the central part of the kidney called the renal medulla. In regions like India, it is most commonly diagnosed in younger individuals of Black descent. Approximately 70% of RMC cases develop in the right kidney.
All RMC cells lose the ability to produce a protein called INI1 (also known as SMARCB1 or BAF47). This protein normally acts as a tumour suppressor.
To confirm RMC, tumour tissue is examined for the absence of the INI1 protein. If the protein is present, the cancer is not RMC. If it is negative, additional tests are required, as other cancers may also lack INI1. Due to the rarity and difficulty in identifying RMC, it is vital that a pathologist (a doctor specialising in disease diagnosis) with specific experience in RMC evaluates the tissue.
In the majority of cases, RMC is associated with genetic mutations that cause red blood cells to become rigid and sickle-shaped. These disorders are known as sickle hemoglobinopathies.
The most frequent of these is the sickle cell trait. Individuals with this trait often live normal lives without symptoms and may not know they have it. Patients diagnosed with RMC must undergo a specific blood test to determine if they carry the sickle cell trait or another sickle hemoglobinopathy.
RMC is an aggressive disease that is often diagnosed late, after it has already spread. It is critical to diagnose RMC correctly because it does not respond to the medications used to treat most other kidney cancers. While survival rates have historically been poor, recent increases in awareness, coupled with improvements in diagnosis and current therapies, have helped more patients survive beyond one year. Research and clinical trials are ongoing to continually enhance care.
In uncommon instances where RMC occurs in individuals without any sickle hemoglobinopathies, it may be classified as renal cell carcinoma, unclassified with medullary phenotype (RCCU-MP). Treatment for this subtype is generally similar to that of RMC associated with sickle hemoglobinopathies.
Due to the internal location of the kidneys, symptoms of kidney cancer often do not become apparent until the tumour has grown to a significant size. Many cases are discovered incidentally during investigations for other medical concerns, such as back pain or kidney stones. When symptoms do occur, they can vary considerably from person to person.
Kidney cancer symptoms may include:
It is important to remember that these symptoms can also be indicative of other, less serious health problems. Any persistent symptoms should be discussed promptly with your doctor.
A small number of kidney cancers can be hereditary. Genetic counselling may be appropriate to assess the risk to you and your family.
At SSCHRC, our specialists are dedicated to kidney cancer and employ the latest technology to accurately determine the extent and exact location of each tumour.
It is known that while most kidney tumours are malignant (cancerous), some are benign (non-cancerous). Since no imaging test can definitively distinguish between a benign and cancerous kidney tumour, seeking treatment as early as possible is highly important once a tumour is identified.
If you present with symptoms suggestive of kidney cancer, your doctor will conduct a thorough assessment, including questions about your general health, lifestyle (such as smoking and drinking habits), family medical history, and specific details about your symptoms. Based on this, tests will be ordered to diagnose the problem, which may include:
Although no single blood or urine test can conclusively diagnose kidney cancer, these tests are vital for helping doctors rule out or diagnose other potential causes of your symptoms, and they can also indicate the possible presence of cancer.
These examinations are focused on the kidneys and areas where kidney cancer often spreads, such as the lungs, bones, and less frequently, the brain and spine. Imaging exams may include:
This is the only method to definitively diagnose kidney cancer prior to surgery. It involves the removal of a small piece of suspected cancer tissue for microscopic examination. The tissue is typically retrieved by an interventional radiologist using imaging technology to guide a long, thin needle to the tumour, a procedure that is minimally invasive.
Once a diagnosis of kidney cancer is made, your doctor will discuss the optimal treatment plan. This plan is customised to your individual needs at SSCHRC and depends on several factors, including the stage of the cancer and your overall health.
Treatment can be physically taxing, especially for older patients or those in poor health. For these individuals, particularly with small tumours, active surveillance may be a suitable approach. Doctors monitor the cancer through regular blood tests, urine tests, and imaging scans, initiating treatment only if the cancer progresses or if the patient's health status improves.
Surgery is the standard treatment for tumours confined to the kidney or the surrounding area. The surgeon's goal is to preserve as much of the kidney as possible, although in some cases, the entire organ must be removed.
Minimally Invasive Techniques: At SSCHRC, these surgeries are typically performed using minimally invasive techniques, which require only a few small incisions. This can be done with a laparoscope (a thin rod with a camera and surgical tools) or with a robot controlled by the surgeon. Minimally invasive surgery is associated with less pain, shorter hospital stays, and faster recovery times compared to traditional "open" procedures.
Life with One Kidney: It is generally possible to live a normal life with only one functioning kidney. However, if both kidneys are removed or stop working, dialysis (a machine to clean the blood) will be necessary. A kidney transplant may be an option for certain patients.
The two main types of kidney cancer surgery are:
These minimally invasive methods use either heat or cold to destroy the tumour in place, without removing kidney tissue. They are an ideal alternative for smaller kidney tumours in patients who face a high risk from traditional surgery.
Unlike traditional medications that directly kill cancer cells, targeted therapies work to slow or stop the growth and spread of cancer at the cellular level. They interfere with the specific molecules or cancer-causing genes that cancer cells require to survive and multiply. These therapies are primarily used for patients whose disease has spread to other organs.
Most targeted therapies for kidney cancer are angiogenesis inhibitors. These drugs disrupt the process of angiogenesis—the creation of new blood vessels by tumours—which is essential for the cancer to grow.
Immunotherapy drugs do not kill cancer cells directly. Instead, they enhance the patient's own immune system's capacity to identify and eliminate the cancer.
The most common immunotherapies for kidney cancer are checkpoint inhibitors. These medications help the patient's cancer-fighting T cells maintain a stronger, longer-lasting response against the disease.
Traditional chemotherapy is generally ineffective against most kidney tumours and is therefore not widely used. However, it may be employed in specific cases, such as in patients with medullary kidney cancer (RMC).
Standard radiation therapy has a limited role in treating the primary kidney tumour because kidney tumours are not highly sensitive to it, while healthy kidney cells are.
In rare situations, radiation oncologists may use highly focused beams, such as stereotactic radiosurgery, to treat the tumour.
If the cancer has spread beyond the kidney, standard radiation may be used to manage metastases, helping to relieve pain and minimise other symptoms.