**4. Prevalence of biopsies**

partial nephrectomies (**PN**) in the management of T1a tumors. Other approaches such as radiofrequency ablation (**RFA**), cryotherapy and active surveillance (**AS**) are also considered. However, it has been shown that a large proportion of SRMs treated are benign incidentalomas. Twenty percent of surgically removed SRMs have proven to be benign [1, 2] (angiomyolipoma, oncocytoma, metanephric adenoma, etc.), with the figure rising to 29% for tumors <2.5 cm [3]. Thus, it is necessary for current practices to be reevaluated to avoid unnecessary overtreatment. Surgical management based on CT imaging, without pretreatment biopsy, is considered appropriate in most centres. Such an approach not only leads to the patient undertaking unnecessary surgical risks but also places a significant burden on the healthcare system. Premanagement renal tumour biopsies (**RTBs**) have the potential to not only offer holistic

Opponents to RTBs believe that concordance rates of the final pathology with radiological imaging, false-negative rates and potential seeding make this an unreliable procedure. However, the safety and outcomes of RTBs have improved significantly over the last decade. Improved imaging techniques allow for a specific localized tissue to be biopsied. Samples taken from percutaneous needle biopsies also now utilize biomarkers that can lend further

It is important to recognize that avoiding unnecessary surgical treatments is more cost-effective and negates associated risks. In this chapter, we will discuss the improvements of RTBs

It is estimated that 60% of all diagnosed renal cell carcinomas (**RCCs**) are SRMs that are discovered as incidentalomas on ultrasound and/or abdominal CT scans [4]. The current protocol in many urological renal centres, following the discovery of a SRM, is to offer the patient treatment options without a biopsy. Generally, unless contraindicated, these options include PN, RFA, or AS. This approach to treating a SRM is done without a clear histological diagnosis.

There should be a paradigm shift on how SRMs are approached. In some centres, RTBs are now performed upon the discovery of an incidentaloma. Here, patients are referred to an interventional radiologist who will then perform a RTB before their consultation with their urologist. Following the biopsy results from the pathologist, the urologist will meet the

The EAU guidelines recommend RTBs to be performed for AS on selected patients with SRMs, prior to ablative treatments and patients suffering from renal metastatic disease before

**3. Contemporary indications and contraindications for biopsy**

approach to their management but can equally be cost-effective.

insights to the heterogeneous nature of renal neoplasms.

**2. Protocol of SRM management**

112 Evolving Trends in Kidney Cancer

patient and offer better informed treatment options.

embarking on systemic treatment.

and the merits of incorporating them to deliver better outcome measures.

Recent studies have shown that RTBs are still not widely adopted among urologists in clinical practice. A survey in 2010 by Barwari et al. [6] showed that 73% of urologists never take biopsies and only 9% take biopsies in more than 25% of cases. Another survey in 2016 by Richard et al. [7], investigating the prevalence of biopsies for SRMs, showed that only 12% perform RTBs in >75% of cases, while 53% never perform or perform RTBs in <25% of cases.

In both surveys the main reasons urologists cited for not performing biopsies were the lack of influence in clinical management, the risk of false negatives and safety. There is also a radiology-related concern of a lack of expertise with RTBs [7]. These concerns will have to be tackled.

## **4.1. Prevalence of RTBs in active surveillance**

In current literature, many patients undergoing AS have not had a biopsy [8–10]. AS is usually indicated for elderly patients with significant comorbidities or those refusing surgery. Though considered a safe option for patients with SRMs, the risk of developing metastatic disease during surveillance is not ruled out. A systematic review performed by Prins et al. [9] showed that though 1.12% (0–3.2%) of the pooled AS population (968 patients) incurred delayed intervention, only a small proportion of the said population had undergone a RTB. If a biopsy had been performed, it could have led to an earlier appropriate intervention [11]. A systematic review performed by Smaldone et al. [10] looked at the incidence of metastases in AS strategies. In this review of 880 patients, 18 patients (2.05%) progressed to metastatic disease. Unfortunately, only three of these patients had undergone a RTB.

RTBs can also pave the way for a more refined AS strategy and are strongly recommended [8, 10, 12, 13]. If the SRM proves to be histologically benign, a less stringent follow-up protocol can be adopted, or the patient may even be discharged. Higher metastatic potential masses that are better suited for surgical intervention can also be identified. Thus, RTBs can stratify patients into a low-risk or high-risk surveillance strategy.

#### **4.2. Prevalence of RTBs in radiofrequency ablation**

In some centres performing RFA, RTBs are either done at the time of the procedure or not performed at all [14–16]. These patients continue to be treated with a presumptive diagnosis of renal cancer based on CT/US imaging. This increases the rate of RFA performed for benign or indeterminate pathology [15]. Performing RTBs prior to ablative techniques can also be used to stratify patients—where those with unfavorable histology can be triaged to surgery instead.

was also a high histological concordance observed. Patel's study highlighted the concern of a

Renal Tumor Biopsies: A Shift towards Improving Outcomes in the Management of Small Renal Masses

http://dx.doi.org/10.5772/intechopen.85781

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However, repeat biopsy led to diagnosis in 80% of previously undiagnostic biopsies. It is reported that following a non-diagnostic biopsy, a repeat biopsy has a high rate of rendering a diagnosis—ranging from 67 to 85% [22]. Therefore, in the case of a non-diagnostic biopsy,

With overall improved diagnostic accuracies of RTBs, urologists should be more reassured

Reported concerns regarding the safety of RTBs stem from the risks of bleeding, pneumothorax and tumor seeding [7]. Rising literature appraising the choice of gauge needles, imaging modality and preference for core biopsies over FNA have improved the safety of RTBs.

In Patel's et al. study [21], complication rates observed were quite low. The rate of haematomas was 4.9%, while the occurrence of any clinically significant pain was 1.2%. Pneumothorax was only detected in 0.6% of cases, and no study reported any cases of tumor seeding. In Marconi's et al. study [17], the median complication rate was 8.1% with only three Clavien

Tumor seeding along the needle tract is anecdotal and very rare. As per the EAU reported guidelines, to avoid any such complication, coaxial sheaths should be used. This allows mul-

Despite the high concordance rates in identifying tumor subtypes (as mentioned above), the heterogeneous nature of RCC in itself is an identified barrier in adopting RTB. It is essential for clinicians to identify the challenges in discerning between specific tumor subtypes in order

The four main subtypes of RCC include clear cell RCC (**ccRCC**), papillary RCC (**pRCC**), chromophobe RCC (**chRCC**) and collecting duct carcinoma (**CDC**). There are over 10 such subtypes with many inherited syndromes [23]. Each subtype is associated with its own prognostic factors from clinically indolent (pRCC type 1, chRCC) to highly metastatic (pRCC type 2 or ccRCC). Thus, it is valuable for a subtype to be distinguished from benign lesions and also

Another systematic review by Patel et al. [24] investigated the success of identifying oncocytomas. Of the 48 lesions that were diagnostic of oncocytoma on RTB, 64.6% was in concordance with analysis following surgical treatment. Meta-analysis determined the PPV of oncocytoma on RTB to be 67% with a notable proportion to be identified as chRCC. Histologically, they are hard to distinguish as both have an eosinophilic cytoplasm. Clinical diagnostic dilemmas between chRCC and oncocytomas still remain. Clinicians should factor this in tailoring an

tiple passes through the renal mass with only one through surrounding tissue.

reasonable non-diagnostic rate (14.1%).

there is merit in performing a repeat biopsy.

about their successes.

**5.3. Managing complications**

grade ≥2 complications to be reported.

**5.4. Discerning tumour heterogeneity**

altered AS for oncocytomas.

to have a comprehensive grasp on the reliability of a RTB.

to be reliably identified for a more tailored management.
