Tumors of the Kidney

When ultrasound reveals a cystic renal lesion with internal irregularities or suspicious septa, the possibility of a neoplasm should be considered. However, ultrasound alone is not sufficient to establish a definitive diagnosis, and further second-level imaging studies are required.

The reference examination is contrast-enhanced computed tomography (CT) of the abdomen. This investigation allows clinicians to:

• Precisely define the size and location of the lesion
• Assess possible extension of the tumor beyond the kidney (extrarenal spread)
• Identify the presence of enlarged lymph nodes
• Evaluate the possible presence of distant metastases

In selected cases, such as when CT cannot be performed because of contrast medium allergy or other contraindications, or when the lesion presents particularly complex features, magnetic resonance imaging (MRI) may be used. MRI provides highly detailed images and represents an excellent alternative or complementary tool for diagnostic assessment.

In the diagnostic evaluation of kidney cancer, percutaneous renal biopsy, performed under ultrasound or CT guidance, may be useful in selected cases.

This procedure involves collecting a small tissue sample and is particularly indicated when a renal mass presents atypical features that do not allow a definitive diagnosis based on imaging studies alone.

Histological analysis of the specimen helps clarify the nature of the lesion and allows clinicians to guide treatment decisions more accurately and appropriately.

Kidney tissue samples obtained through biopsy are sent to the pathology laboratory, where they undergo microscopic histological examination. If tumor cells are identified, the pathologist determines whether the lesion is benign or malignant.

From an anatomo-pathological perspective, renal masses are broadly classified into benign and malignant tumors.

Benign Renal Tumors

The most common benign renal tumors include:

• papillary adenoma
• fibroma or hamartoma
• angiomyolipoma
• oncocytoma

Malignant Renal Tumors

Renal cell carcinoma is subdivided into the following main histological types:

• non-papillary, so-called clear cell carcinoma
• papillary carcinoma
• chromophobe carcinoma
• collecting duct carcinoma

Conservative Surgery (Partial Nephrectomy)

Conservative surgery, or partial nephrectomy, is currently considered the first-choice surgical treatment for localized stage T1 renal cell carcinoma. It represents the gold standard, particularly in cases of small renal masses (tumors measuring less than 4 cm, stage T1a).

The aim of this approach is to remove the tumor while preserving as much healthy kidney tissue as possible, thereby maintaining renal function and reducing the risk of long-term complications.

Partial nephrectomy is:

• An absolute indication in patients with a single functioning kidney, reduced renal function, or bilateral renal tumors
• The preferred option even in patients with a healthy contralateral kidney, whenever the lesion is technically resectable

In selected cases, even larger tumors (over 7 cm) can be successfully treated using this technique.

To accurately define tumor margins and extension, surgeons may use intraoperative ultrasound, which provides real-time imaging during the procedure. In addition, at the Candiolo Cancer Institute, advanced three-dimensional CT reconstruction technologies integrated into robotic surgery allow highly precise preoperative planning and intraoperative guidance.

Radical Nephrectomy

Radical nephrectomy is a surgical procedure that involves complete removal of the affected kidney, together with the surrounding Gerota’s fascia, the ipsilateral adrenal gland, and a portion of the ureter, following ligation of the renal artery.

The procedure can be performed using different surgical approaches:

• open surgery, through a single incision
• laparoscopic surgery, using small incisions with specialized instruments and a camera
• robot-assisted surgery, which enhances precision through robotic technology

Today, laparoscopic radical nephrectomy is considered the standard approach for patients with stage T1 tumors not suitable for partial nephrectomy (when conservative surgery is not technically feasible due to tumor location or growth pattern) or for stage T2 disease. This technique offers the advantages of faster recovery and reduced postoperative discomfort, while maintaining oncological effectiveness comparable to open surgery.

Radiofrequency ablation (RFA) and cryoablation techniques represent minimally invasive options for the treatment of small renal masses. These procedures offer some important advantages, such as lower morbidity (i.e., they cause fewer complications, side effects, or treatment-related problems), the possibility of outpatient treatment in some cases, and the ability to operate even on patients with a high anesthesiological risk.

The main indications for these methods involve renal masses less than 4 cm in size, often incidentally discovered, and located in the cortical portion of the kidney. They are particularly useful in:

• Elderly patients or patients with multiple associated diseases (comorbidities);

• Patients with genetic predisposition to the development of multiple or successive cancers over time;

• Patients with renal tumors in both kidneys;

• patients with only one kidney and at high risk of needing chronic dialysis in case of surgical resection.

Absolute contraindications are the presence of uncorrectable coagulopathies and conditions of severe organic instability, such as septic pictures.

Importantly, the risk of recurrence after ablative treatment is higher than with conservative surgery, which may result in the need for further treatment. However, for some patients these techniques are an effective and less invasive option

In recent years, alongside ablative techniques, active surveillance has emerged as a viable alternative to surgery in selected patients. This approach is particularly appropriate for small renal masses measuring less than 4 cm, which are increasingly detected incidentally, especially in elderly patients with multiple comorbidities. In these cases, surgical intervention may carry significant risks, both in terms of perioperative mortality and postoperative complications. Moreover, life expectancy may be shorter than the natural progression time of the disease.

It should also be noted that a substantial proportion of these small renal lesions, up to 20 percent, are ultimately found to be benign, following more in-depth diagnostic assessment such as biopsy or surgical histological examination.

Active surveillance therefore consists of close and regular monitoring of the renal mass through periodic imaging studies, postponing treatment and intervening only if disease progression is observed.

Radical nephrectomy, meaning the complete removal of the affected kidney, represents the only potentially curative option when the tumor can be entirely excised.

However, in cases of advanced disease with distant metastases, nephrectomy is no longer considered curative but may still play an important clinical role.

In these situations, the procedure is defined as cytoreductive nephrectomy, a surgical approach aimed at reducing tumor burden as much as possible, even when complete removal is not feasible. This strategy may enhance the effectiveness of subsequent systemic therapies and contribute to better symptom control.

Cytoreductive nephrectomy is considered when technically feasible and when the patient’s clinical condition allows surgery, with the primary objective of optimizing overall outcomes and preserving quality of life.

In selected cases of metastatic renal cancer, surgery can be used to remove metastases, especially if they are few and located in accessible areas, such as the lungs or liver. This strategy, called metastasectomy, can help improve disease control and, in some patients, prolong survival.

The decision to surgically intervene on metastases is evaluated on a case-by-case basis, considering the amount, site of metastases, general status of the patient, and response to systemic therapies.

Metastasectomy is usually part of a multidisciplinary approach that includes medical therapies such as target therapy or immunotherapy.

Radiation therapy can be used in patients with brain or bone metastases that cannot be surgically removed. In these cases, radiation therapy helps to significantly reduce symptoms, improving quality of life.

The introduction of biologic drugs has transformed the treatment landscape of metastatic renal cancer, providing new therapeutic options that have significantly improved disease management.

Today, treatment options for metastatic renal cell carcinoma include targeted therapies and immunotherapy. Targeted therapies act on specific molecular pathways involved in tumor growth, inhibiting cancer cell proliferation and/or interfering with the tumor’s blood supply. Immunotherapy, by contrast, enhances the body’s immune response, enabling the immune system to recognize and attack cancer cells more effectively.

To ensure timely and direct support and to provide prompt answers to concerns and questions, the Candiolo Cancer Institute has established a dedicated helpline for all patients.

From Monday to Friday, between 8:00 a.m. and 5:00 p.m., patients can contact the Oncology Day Hospital secretariat at +39 011.993.3775 to request urgent consultation.

Patients are then promptly put in contact with their referring medical specialist to receive clear information and immediate support.

The cancer patient is a complex patient who requires multidisciplinary support for the management, not only of his or her pathology, but also of all associated clinical and functional needs.

At the Candiolo Cancer Institute, specialists from multiple disciplines are available to support patients who require or request additional care, offering:

• • nutritional support

• • physiotherapy

• • pain therapy

• • Management of other coexisting conditions.

The Social Service Department of the Candiolo Cancer Institute offers information and orientation interviews aimed at patients and their families, to facilitate access to services in the area and to welfare and social security benefits provided by law (disability, benefits for aids and prostheses, work leave, etc.).

The service is available on Wednesdays and Fridays, from 9 a.m. to 1 p.m. Information is available by calling +39 011.993.3059.

The main goal of follow-up after surgical treatment of renal carcinoma is the early detection of any local recurrence or distant metastasis, allowing timely intervention while the disease remains potentially curable.

In patients with metastatic disease, follow-up is tailored individually, whereas in those with localized disease treated with curative intent, standardized surveillance protocols are applied. These protocols take into account both the individual risk profile and the effectiveness of the treatment performed.

It is important to note that in specific situations, such as after radiofrequency ablation (RFA) or cryoablation, in cases of large tumors (>7 cm) treated with nephron-sparing surgery, or in the presence of positive surgical margins, the risk of local recurrence is higher. In these cases, follow-up is intensified to ensure closer and more frequent monitoring.