Renal cancer: signaling pathways and advances in targeted therapies

Renal cancer is a highlyheterogeneous malignancy characterized by rising global incidence and mortalityrates. The complex interplay and dysregulation of multiple signaling pathways,including von Hippel-Lindau (VHL)/hypoxia-inducible factor (HIF), phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR), Hippo-yes-associated protein (YAP), Wnt/ß-catenin, cyclic adenosine monophosphate (cAMP), and hepatocyte growth factor (HGF)/c-Met, contribute to theinitiation and progression of renal cancer. Although surgical resection is thestandard treatment for localized renal cancer, recurrence and metastasiscontinue to pose significant challenges. Advanced renal cancer is associatedwith a poor prognosis, and current therapies, such as targeted agents andimmunotherapies, have limitations. This review presents a comprehensiveoverview of the molecular mechanisms underlying aberrant signaling pathways inrenal cancer, emphasizing their intricate crosstalk and synergisticinteractions. We discuss recent advancements in targeted therapies, includingtyrosine kinase inhibitors, and immunotherapies, such as checkpoint inhibitors.Moreover, we underscore the importance of multiomics approaches and networkanalysis in elucidating the complex regulatory networks governing renal cancerpathogenesis. By integrating cutting-edge research and clinical insights, this review contributesto the development of innovative diagnostic and therapeutic strategies, whichhave the potential to improve risk stratification, precision medicine, andultimately, patient outcomes in renal cancer.

Transition From Open and Laparoscopic to Robotic Partial Nephrectomy: Learning Curve and Outcomes

Introduction Partial nephrectomy (PN) is the current standard of care for patients with T1 renal tumors, and there has been a shift from an open and laparoscopic to a robot-assisted approach. The definition of the learning curve for robot-assisted PN (RAPN) is unclear, and various studies have identified warm ischemia time (WIT), perioperative complications, and surgical margins as the defining parameters for the assessment of improvement in these outcomes over time. The objective of this study was to evaluate the learning curve of a newly trained urologist for RAPN when comparing both open and laparoscopic approaches. Methods This study included 52 patients who underwent PN by open, laparoscopic, and robotic methods performed by a single, newly trained urologist over a period of seven years. Basic demographic and perioperative data were collected, and the learning curve was compared between the three approaches. Results Baseline parameters were similar for open (n = 15), laparoscopic (n = 12), and robotic (n = 25) PN except for tumor size and nephrometry score, which were higher in the open group (p = 0.000). Operative time was significantly longer in the robotic approach (180 minutes; p = 0.05), and blood loss was greater in the open group (450 mL; p = 0.000). Median WIT was 25 minutes; significant complications (Clavien Dindo ≥II) and positive surgical margins were 12% and 0%, respectively, in the robotic arm. Preoperative imaging and final histopathology data showed larger tumors being operated on, preferably by an open method, than laparoscopic and robotic PN (6.3 cm vs. 3.4 cm; p = 0.000). More open and laparoscopic procedures (n = 12, 10) were performed during the initial 26 cases, with a later transition to robot-assisted PN (n = 21) in the next 26 cases. None of the parameters showed improvement in the latter half, while operative time showed an increase (150 vs. 180 minutes; p = 0.045). Conclusion The learning curve becomes similar across three defined parameters, i.e., WIT, perioperative complications, and positive surgical margins, after performing a minimum of 25 RAPNs when compared to open and laparoscopic approaches. However, operative duration continues to improve and may take longer to become comparable. A newly trained urologist can safely perform RAPNs even with a small number of cases, especially those who have been previously trained for open and laparoscopic cases.

Short-Term and Long-Term Renal Outcomes in Patients With Obesity After Minimally Invasive Versus Open Partial Nephrectomy for the Treatment of Renal Cancer: Retrospective Study

Background

Obesity is significantly associated with renal cell carcinoma. Surgery is the preferred treatment for demarcated lesions of renal cell carcinoma; however, obesity increases the complexity of surgical outcomes. Minimally invasive surgical techniques are preferred over open partial nephrectomy (OPN), but controversy remains regarding the most efficacious technique in patients with obesity.

Objective

This study aims to determine whether minimally invasive partial nephrectomy (MIPN) or OPN better preserves renal function and investigate short- and long-term renal outcomes in patients with obesity undergoing a partial nephrectomy.

Methods

We conducted a retrospective chart review of 242 adult patients aged ≥18 years who underwent MIPN or OPN between January 1, 2005, and December 31, 2016, at the University of Arkansas for Medical Sciences. Using creatinine as a measure of kidney function, patients’ preoperative levels were compared with their postoperative levels in 2-time frames: short (3-6 months postsurgery) or long (>6 months). The primary outcome was the change in creatinine values from preoperative to >6 months postoperatively in patients with obesity. Secondary outcomes included the change in creatinine values from preoperative to 3 to 6 months postoperatively in patients with obesity who underwent MIPN versus OPN. We also analyzed the creatinine values of nonobese patients (BMI <30) who underwent partial nephrectomy using the same time frames. Unconditional logistic regression was used to estimate crude and multivariable-adjusted odds ratios (ORs) and 95% CI to observe associations between surgery type and changes in creatinine values from while stratifying for obesity.

Results

A total of 140 patients were included in the study, of whom 75 were obese and 65 were nonobese. At >6 months after MIPN (n=20), the odds of patients with obesity having a decrease or no change in creatinine values was 1.24 times higher than those who had OPN (n=13; OR 1.24, 95% CI 0.299-6.729; P=.80). At 3 to 6 months after MIPN (n=27), the odds were 0.62 times lower than those after OPN (n=17; OR 0.62, 95% CI 0.140-2.753; P=.56). In the nonobese group, at 3 to 6 months after undergoing minimally invasive surgery (n=18), the odds of having a decrease or no change in creatinine values was 4.86 times higher than those who had open surgery (n=21; OR 4.86, 95% CI 1.085-21.809; P=.04). At more than 6 months after MIPN (n=14), the odds were 4.13 times higher than those after OPN (n=11; OR 4.13, 95% CI 0.579-29.485; P=.16).

Conclusions

We observed a nonstatistically significant preservation of renal function in patients with obesity who underwent OPN at 3 to 6 months postoperatively. Conversely, after 6 months, the same was true for MIPN, indicating the long-term benefit of MIPN. In the nonobese group, MIPN was favored over OPN. 

The BMI Paradox and Robotic Assisted Partial Nephrectomy

Introduction: Partial nephrectomy (PN), has become the gold standard for the surgical management of small renal masses, due to excellent oncologic control with concomitant preservation of nephron units. However, data regarding the association of obesity with perioperative outcomes following PN are mixed. Therefore, the association between obesity (using BMI) and post-operative complications (POC) rate following Robotic assisted laparoscopic PN (RPNx) was tested.

Methods: Two hundred and fifty-one adult patients who underwent RPNx from 1/2011 to 5/2017 at a single institution, with at least 90 days follow-up were identified and included. No patients were excluded. Electronic medical records were reviewed to record all POC within 90 days of surgery. A piecewise generalized linear model for binary outcomes (logistic) was used to model the proportion of subjects with POC by their BMI. The slope of the line is adjusted to a BMI of 30 Kg/m².

Results: BMI is significantly associated with POC rate. POC rate decreased with increasing BMI below the inflection point of 30 Kg/m² (0.848[0.756, 0.952]) (OR [95% CI], p = 0.005). POC rate was found to increase with increasing BMI above the BMI inflection of 30 Kg/m² (1.102 [1.027, 1.182], p = 0.0071).

Conclusions: In this cohort study, BMI showed an association with PC. It may be important to take BMI into account in surgical and clinical management considerations of RPNx, since higher rates of POC are associated with patients who are underweight, morbidly obese, and even with normal BMI. Further research is required on larger cohorts of RPNx patients to provide better description of this phenomenon and elucidate the role of BMI in development of POC.

[Standard surgery for small renal masses (<4 cm)]

BACKGROUND

Several new treatment strategies have emerged in the treatment of small renal masses (<4 cm in diameter). Active surveillance and ablative techniques have been introduced but it remains unclear which patients will benefit the most from these new treatment options. A surgical approach remains standard of care. In recent decades, radical nephrectomy has been replaced by nephron-sparing surgery for the management of small renal masses.

RESULTS

In addition to the open partial nephrectomy, which is considered the standard approach, the number of surgeries performed using minimally invasive techniques is increasing. Recent data show that there might be some benefits such as less blood loss. The disadvantages shown by laparoscopic partial nephrectomy such as prolonged warm ischemia, longer operation times, and postoperative renal impairment might be negligible for the robotic approach. Therefore, current guidelines allow these approaches in addition to open partial nephrectomy if sufficient surgical expertise is given.

Laparoscopic renal surgery is here to stay

Objectives

To review the current literature comparing the outcomes of renal surgery via open, laparoscopic and robotic approaches.

Materials and methods

A comprehensive literature search was performed on PubMed, MEDLINE and Ovid, to look for studies comparing outcomes of renal surgery via open, laparoscopic, and robotic approaches.

Results

Limited good-quality evidence suggests that all three approaches result in largely comparable functional and oncological outcomes. Both laparoscopic and robotic approaches result in less blood loss, analgesia requirement, with a shorter hospital stay and recovery time, with similar complication rates when compared with the open approach. Robotic renal surgeries have not shown any significant clinical benefit over a laparoscopic approach, whilst the associated cost is significantly higher.

Conclusion

With the high cost and lack of overt clinical benefit of the robotic approach, laparoscopic renal surgery will likely continue to remain relevant in treating various urological pathologies.

Feasibility of laparoscopic partial nephrectomy in the obese patient and assessment of predictors of perioperative outcomes

Introduction:

Partial nephrectomy is the gold standard for treatment of small renal masses. Our study compares outcomes for obese (body mass index [BMI] ≥30) and healthy (BMI <30) patients undergoing laparoscopic partial nephrectomy (LPN) with the intention of defining preoperative risk factors for complications and renal insufficiency in the obese.

Materials and Methods:

We conducted a retrospective review of 187 consecutive patients who underwent LPN. We examined the association between BMI and postoperative complication, estimated blood loss (EBL), hospital length of stay, warm ischemic time (WIT), and postoperative renal function. We did similar analyses using the RENAL nephrometry score and the comorbidity status of the patients.

Results:

We found no statistically significant increase in complications in obese (BMI ≥30) individuals relative to healthy (BMI <30) patients. The obese experienced approximately 100 cc more EBL (P = 0.0111). Patients experienced more complications if they had a Charlson comorbidity score ≥3 (P = 0.0065), an American Association of Anesthesiologists score ≥3 (P = 0.0042), or a history of diabetes mellitus (P = 0.0196). There was no association between RENAL nephrometry score and complication. However, patients with a score ≥8 experienced higher WIT (P = 0.0022), a greater decline in estimated glomerular filtration rate postoperatively (P = 0.0488), and an increased risk of developing chronic kidney disease ≥3 (P = 0.0065).

Conclusions:

Obese patients undergoing LPN are not at significantly increased risk of complication relative to nonobese patients. Comorbidity status and RENAL nephrometry score, independent of BMI, should be the main considerations of a patient's suitability for LPN.