What is Kidney Cancer?
The kidney’s job is to filter the blood. This means that certain toxins or excessive amounts of products in the blood are eliminated through the urine.
This organ comprises different types of cells that grow, multiply and die in a continual process of cellular renewal.
When this cycle of renewal changes and abnormal cells are produced or are not destroyed at the right time, tumours form.
The occurrence of these situations has increased considerably over the last 25–30 years (around 2% per year) partly due to increased diagnosis of small lesions via imaging scans.
Kidney Cancer Risk Factors
High blood pressure
Family health history
Other situations with possible associations to kidney tumors include chronic kidney disease, exposure to radiation, and the use of non-steroidal anti-inflammatory drugs.
Types of Kidney Tumors
There are several types of kidney tumors:
- Renal Cell Carcinomas (RCC), which are tumors of the renal parenchyma itself. They are the most common malignant tumors of the kidney, accounting for over 90% of all kidney malignancies, representing about 2 to 3% of all malignant neoplasms in adults and being responsible for 2% of cancer-related deaths. There are various histological subtypes, such as clear cell, papillary, or chromophobe.
- Upper Tract Urothelial Carcinomas (UTUC), which are tumors of the excretory part of the kidney, consisting of the same cells that line the ureter, bladder, or urethra, and are therefore associated with these.
- Benign tumors, such as oncocytomas, angiomyolipomas, and adenomas.
- Other malignant tumors, such as sarcomas, medullary carcinomas, collecting duct carcinomas, lymphomas, or kidney infiltration by metastases from tumors in other organs.
Kidney Cancer Symptoms
In the early stages, kidney tumors exhibit very slow growth, typically around 2-3mm per year. During this phase, there are no symptoms or warning signs.
For this reason, and due to the widespread availability of diagnostic tests such as ultrasound, computed tomography, or magnetic resonance imaging, which are often conducted for other reasons, the vast majority of kidney tumors (approximately 60%) are currently diagnosed incidentally.
On the other hand, if left undetected, kidney tumors progressively increase in size and become more aggressive over time.
The patient may have:
In the later stages, kidney tumors can become invasive and give rise to various symptoms, including:
- Lower back pain: This results from the tumor's growth and the stretching of the kidney's capsule.
- Hematuria: This is the most common isolated symptom, caused by the involvement of the urinary tract.
- Palpable mass: A late sign of advanced disease.
Other symptoms may include loss of appetite, intermittent fever, progressively worsening fatigue, or edema in the lower limbs.
The tumor can also manifest through paraneoplastic syndromes or symptoms resulting from systemic metastasis.
Kidney Cancer Diagnosis
The diagnosis of kidney cancer is typically made through imaging exams. In many cases, ultrasound is the initial diagnostic tool for identifying kidney tumors. It is non-invasive, safe, and highly sensitive for detecting lesions larger than 15mm.
However, contrast-enhanced computed tomography (CT) is the preferred imaging exam for kidney tumors. In the vast majority of cases, when performed correctly, CT scans can diagnose kidney tumors without the need for a biopsy. They also allow for disease staging and treatment planning.
In very specific cases, magnetic resonance imaging (MRI) may be an alternative to CT scans.
Rarely, when there is uncertainty with the imaging results, a biopsy of the tumor lesion may be necessary.
Do you have any of these kidney cancer symptoms?
Kidney Cancer Treatment
The treatment of kidney tumors depends on various factors, with the most relevant being the staging of the tumor and the overall health and functional status of the patient.
In localized stages, the most common treatment is surgery, which offers a high probability of cure. Currently, in the majority of cases, laparoscopic procedures can be performed, which are associated with lower complication rates and faster recovery. Depending on the tumor's characteristics, it may be possible to remove only the tumor and preserve the kidney (partial nephrectomy). When this is not possible, complete removal of the kidney (radical nephrectomy) is performed. In selected cases, particularly for frail patients, focal therapies such as cryotherapy or radiofrequency treatment can be considered. Additionally, in highly selected cases, in older patients with small renal tumors without aggressive features, active surveillance may be a viable option.
In advanced stages, given the aggressiveness of the disease, most treatments have a palliative nature. In addition to surgery, systemic therapy or radiation therapy may be employed. However, in recent years, there has been significant progress in systemic treatments, particularly immunotherapy. Through the combination of various drugs, immunotherapy has significantly increased the survival and quality of life of patients with advanced kidney tumors.
Kidney Cancer Prognosis
Assessing prognostic factors has undergone a major evolution in recent years and now uses isolated parameters to combine various factors.
When establishing a carcinoma prognosis, factors such as age, sex, race and performance status are assessed as well as anatomical and histopathological factors.
The main characteristics of the latter two are:
- Assessment of the stage;
- Lesion size and extent;
- Number and location of possible metastases;
- Histological subtype of the tumour;
- Venous incursion;
- Tumour necrosis.
This research culminated in the creation of various integrated prognostic models, given the variability in clinical evolution of this neoplasm according to the different parameters.
Dr. José Santos Dias
Clinical Director of the Instituto da Próstata
- Bacherlor's Degree from the Faculty of Medicine at the University of Lisbon
- Specialist in Urology
- Fellow of the European Board of Urology
- Autor dos livros "Tudo o que sempre quis saber Sobre Próstata", "Urologia fundamental na Prática Clínica", "Urologia em 10 minutos","Casos Clínicos de Urologia" e "Protocolos de Urgência em Urologia"
FAQs about Kidney Cancer
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- DIAS, José Santos. Urologia Fundamental: na prática clínica. Lisboa: Lidel - Edições Técnicas, Lda, 2010.
- What is Kidney Cancer?- https://www.nm.org/conditions-and-care-areas/cancer-care/genitourinary-cancer-care/kidney-cancer
- Kidney Cancer - https://www.mayoclinic.org/diseases-conditions/kidney-cancer/symptoms-causes/syc-20352664