In 2009, the incidence of malignant tumours arising from the renal parenchyma in Poland is estimated to have been 14.8/100 000 in men and 9.5/100 000 in women, while the associated death rates were 8.4/100 000 and 5.0/100 000, respectively (1). Among renal tumours, the dominating renal cell carcinoma (RCC) arises from the proximal canaliculi of the nephron. RCCs comprise at least 3% of all malignant neoplasms (2), while their incidence in Europe grows annually by 2% (3). RCC occurs 1.5-2 times more frequently in men compared to women (4), and the incidence rises in the sixth and seventh decades of life (5). The main risk factors of RCC are tobacco smoking, obesity and arterial hypertension (6, 7). In the majority of patients, RCC is a sporadic tumour, with only 2-3% occurring in a familial background (7).

“Renal cell carcinoma” is a broad term. It encompasses several histologically dissimilar tumours. The one with the highest incidence is clear cell carcinoma (CCC), which makes up 70-80% of all RCCs. The remaining types are papillary cancer (10-15%), chromophobic cancer (3-5%) and an exceptionally malignant cancer arising from the collecting duct epithelium (collecting duct carcinoma), also known as Bellini’s tumour (< 1 %) (8).

The signs and symptoms associated with solid renal tumours are not characteristic. The main ones include pain, haematuria, and a palpable mass in the kidney region, collectively known as Israel’s triad. Tumours found when diagnostic workup was induced by symptoms are usually advanced. Ever since ultrasound and computed tomography imaging became widely available, there is a growing number of cases identified accidentally by studies performed for “non-urological” indications. Incidental renal tumours (IRT), also called “imaging tumours”, are usually smaller than “symptomatic” tumours. The proportion of fortuitously diagnosed tumours in the total number of diagnosed renal tumours is currently approx. 60% (9,10).

The only method of primary treatment of RCC is surgery, while the type and scope of the operation depend chiefly on the disease stage. The grading of the cancer based on a four-grade Fuhrman scale (11) can be determined after tumour excision, since percutaneous lesion biopsy is not deemed to be a part of standard preoperative management. The latter is only applied when the tumour is to be removed by a minimally invasive method executed through thermal ablation.

Less advanced stages and smaller sizes of RCCs at the time of diagnosis as well as a better understanding of the biology of these tumours has encouraged the search for surgical methods that would be less invasive and more limited in scope compared to the classic radical nephrectomy (RN), which has been the mainstay of treatment. Currently, in cases with a favourable anatomical location of the tumour, which measures no more than 7 cm in its largest diameter, nephron-sparing surgery is advocated (NSS).

The pioneer of partial nephrectomy (PN), also known as kidney resection, is Vincent Czerny, who performed a renal parenchyma-sparing operation in 1887. However, this method was not broadly adopted due to numerous complications. Currently, PN is recommended for tumours measuring up to 4 cm in diameter (cT1a) and is a method of choice for tumours measuring between 4 and 7 cm, which are limited to the kidney (cT1b), provided that it is technically feasible (12-24). The occurrence of major complications, which were reported earlier, has been greatly reduced by the advent of new techniques, devices and materials, however, the risk of their emergence should not be ignored. They can include secondary bleeding from the resected kidney, and urinary or arterio-venous fistulas, which may lead to serious haematuria. The fundamental advantage of PN is the preservation of the unaffected part of the kidney. This markedly reduces the risk of chronic renal failure, which may emerge with varied delay following total nephrectomy, especially in patients with diabetes, atherosclerosis or arterial hypertension (25). According to some authors, the quality of life of patients subjected to PN is superior to that of patients treated by radical nephrectomy (26, 27). Moreover, the execution of surgery with a short period of renal ischaemia usually does not impair renal function (28).

Until recently, the indications for PN were limited to the so-called absolute kind and included tumours developing in an anatomically or functionally single kidney (i.e. absence of the contralateral kidney or failure or complete lack of function of the contralateral kidney), as well as a bilateral RCC. Currently, these have been broadened to include relative indications, which regard patients with a risk of future failure of the contralateral kidney; or with a genetic defect, which increases the risk of renal tumours developing in the future, as in syndromes like von Hippel-Lindau, hereditary papillary RCC, familial leiomyomatosis, Birt-Hogg-Dubé (29, 30); as well as elective indications, such as the technical feasibility and safety of PN in patients, whose contralateral kidney is intact (12).

Partial nephrectomy can involve the resection of the inferior, superior, or even central fragment of the kidney, which contains the tumour, together with a margin of macroscopically unaltered renal parenchyma (a margin of 1 mm is sufficient). It is performed retroperitoneally via lumbotomy (open surgery) or, with increasing frequency, by laparoscopy or retroperitoneoscopy (endoscopic surgery without opening of the peritoneal cavity). Surgery is performed in conditions of ischaemia achieved after clamping the major vessels of the renal pedicle, or preferably, if possible, the selective clamping of vessels supplying the resected fragment of the kidney. The duration of ischaemia is critically important for the later function of the resected kidney. In the case of so-called “warm ischaemia”, its duration should not exceed 20 minutes (31). On the other hand, if “cold ischaemia” is applied by packing the kidney with sterile crushed ice, its duration can be safely extended up to 60 minutes (32). PN reduces the risk of renal failure. McKiernan et al. performed a 10-year prospective study, which enrolled 290 patients with RCC measuring up to 4 cm, in whom the contralateral kidney was normal. The study compared 173 patients treated by radical nephrectomy (RN) with a group of 117 patients treated by PN. The former group had a higher risk of developing chronic renal failure, compared to the latter group (33). Dash et al. performed a prospective study, which followed 196 subjects with RCC measuring 4-7 cm, in whom either RN or PN was performed. They found that 3 months post-op, creatinine levels were significantly lower in patients treated with PN (20). Nevertheless, the most important goal regarding PN is to achieve long-term oncological outcomes that match classic radical nephrectomy. Lee et al. compared PN and RN outcomes in patients with RCC tumours measuring < 4 cm finding that 5-year survival without local recurrence is comparable for both types of treatment (34). Many other papers have reported similar outcomes of PN and RN in patients operated for tumours measuring < 7 cm (13, 17, 18, 20, 22, 24).