A 60-year old diabetic lady presented with an incidentally detected right renal tumour. Computed tomography (CT scan) showed a small renal mass (2 x 1 cm), in the right kidney, partly exophytic, with adequate distance from the hilum and collecting system. As a patient of this modern world, she had undergone a series of additional investigations prescribed by her family physician, including Positron emission tomography with CT(PET-CT) and biopsy of the renal tumour. The biopsy confirmed a clear cell type of renal cell carcinoma, which is the most common and more dreaded variant for a localised malignancy. Renal score was 5a. Laparoscopic partial nephrectomy was performed, with an uncomplicated intro-operative and post-operative period. Final histopathological diagnosis confirmed a pT1a clear cell RCC with adequate oncological margins. She is at present on follow-up.
Small renal masses are defined as renal tumours measuring less than 4 cm in their greatest dimension. With the advent of improved radiological technology and more patients undergoing diagnostic tests for unrelated indications, there is an increase in the number of patients being diagnosed with renal tumours at earlier stages. As per the AJCC-TNM staging, an SRM falls under the T1a category, meaning an early lesion in case it is malignant, confined within the kidney.
The management of the lesion pertains to what we suspect based on the radiological findings and the need for supplementary investigations. One must not forget that the treatment also needs to be catered as per the age and additional co-morbidities of the patient, especially keeping in mind any renal dysfunction. Pre-existing renal function is an important factor in the management of an SRM. Computed tomography adds value with respect to characterising the lesions through the various phases of contrast enhancement (plain, arterial, nephrogenic, venous, excretory). This helps us define them better and understand the possible pathology. Magnetic resonance imaging contributes tremendously to those with pre-existing renal failure and pregnant women, avoiding the need for contrast and radiation exposure, respectively.
When doubts are raised in terms of the possible pathology, is a biopsy indicated? Biopsy may be indicated in case of doubt concerning the diagnosis of the lesion or any diagnosis that can alter the course of treatment. For example, if suspecting a lymphoma, then the primary one of treatment is chemotherapy, which cannot be given without a proven tissue diagnosis. Other conditions needing biopsy are when suspecting renal abscess, metastasis to the kidney, or need for a diagnosis in case of managing a patient with active surveillance or thermal ablative treatment. Twenty percent tend to be benign, while another 20 percent tend to be aggressive malignancies. The remaining sixty percent tend to have an indolent course. In the patient described before, biopsy and the PET-CT were additional unnecessary tests which bore no influence on management or the outcome.
Active surveillance is a possible option in those with indolent disease or elderly patient in where associated co-morbidities prioritise them under high-risk category for surgical complications. Regular follow-up with radiological investigations is done. Definitive therapy is implemented when there are signs of progression such as increase in size, vascularity, and presence of locally advanced disease.
The various treatment options for treatment of SRMs include active surveillance, thermal ablative therapies, partial nephrectomy, and radical nephrectomy. The good standard treatment is surgical removal of the tumour. So now comes the question, why preserve a kidney with an existing tumour? Time-tested evidence-based practice has shown that the patients who undergo radical nephrectomy, entailing removal of the entire kidney, have long-term renal dysfunction and mortality due to cardiac causes incited by the same. Also, those with renal tumours of syndromic association such as von Hippel–Lindau(VHL), are bound to recur or have new tumours arising periodically, so renal preservation is pertinent here.
The decision in terms of amenability of resection is based on various nephalometric scoring systems such as RENAL, arterial-based complexity(ABC), C-index, and PADUA. They analyse various factors such as the tumour size, hilar and collecting system proximity, to name a few. A low score makes partial nephrectomy feasible, whereas a higher score makes it difficult to achieve oncologically sound margins and functionally unbreached collecting system. With the advent of innumerable technological achievements, there is an ease with which they help in the accurate dissection and removal of the renal tumour with safe margin and protecting the renal collecting system. Though the clinical vignette given above is an ideal case for a partial nephrectomy, certain other cases may not be so. There may be tumours which are closer or involving the collecting system or abutting the hilum, where performing a partial nephrectomy can be more technically challenging, though possible nonetheless.
The intent behind the article was to make aware that renal tumours are amenable for partial nephrectomy and highlight the necessity to preserve renal parenchyma.The step backward in terms of tumour excision is the step forward for renal function.
Dr. Anu Ramesh MS, DNB (General Surgery), MRCS(Ed), Mch (Urology) Junior Consultant, Department of Urology
