Predictors of surgical outcome in Wilms' tumor: a single-institution comparative experience

Surgical aspects, violations and outcomes of Wilms tumor—a multicenter study in a resource-limited country

Background

Wilms tumor is the commonest malignant renal neoplasm in children. Surgery plays a pivotal role in the management, and evidence-based guidelines for surgical resection have been established by the major international groups. Any deviation from the protocol is considered as a violation. The goal of this study was to evaluate outcomes of the patients with unilateral Wilms tumor treated at a developing country and to analyze surgical violations (SV) and their impact on the prognosis. A retrospective review was conducted for 37 patients who were presented to our hospitals and underwent nephrectomy for WT from January 2016 to December 2018. All participating centers adopt Children’s Oncology Group protocol. The SV were analyzed by logistic regression. Overall survival (OS) and event-free survival (EFS) were estimated by the Kaplan-Meier method.

Results

There were 12 (32.4%), 11 (29.7%), 10 (27%), and 4 (10.8%) stages I, II, III, and IV, respectively. Their median age at time of diagnosis was 3.1 years. Upfront nephrectomy was performed for 30 cases. Six patients had tumor relapse (2 lungs and 4 local recurrences) at a median follow-up of 15.7 months. Out of the relapsed patients, two had unfavorable histology, and regarding their staging, four were stage III, one was stage II, and one was stage IV. Thirty-month OS and EFS were 84.3% and 81.1%, respectively. Twenty-seven SV occurred within 25 patients. Lack or inadequate lymph node sampling represented 74.07% (20/27), intraoperative tumor rupture and spillage accounted for 18.52% (5/27), and unwarranted preoperative biopsy happened in 7.41% (2/27). The SV were not correlated with mortality (p value = 0.381); however, they had a significant impact on the relapse (p value = 0.001). On further analysis; tumor rupture and spillage was a predictor for recurrence reaching a statistical significance (p value = 0.003), whereas the other violations were not.

Conclusions

Favorable outcomes could be achieved by compliance with evidence-based guidelines even in a resource-limited country like ours. Violations were correlated with relapse; however, only tumor rupture and spillage was of statistical significance in multivariate analysis. Failure of lymph node documentation was the main problem encountered, and it should be avoidable in future practice.

[Is nephron-sparing surgery relevant for unilateral Wilms tumors?]

BACKGROUND

Wilms tumors (WTs) are the most frequent renal tumors in children. Radical nephrectomy (RN) remains the gold-standard surgical treatment for this type of cancer. Excellent results in overall survival (>90%) make it possible to consider nephronic preservation. The objective of this systematic review is to evaluate the relevance of nephron-sparing surgery (NSS) for the treatment of nonsyndromic unilateral Wilms tumor (UWT) in children.

METHODS

Articles in English related to "unilateral Wilms tumor, unilateral nephroblastoma, partial nephrectomy, nephron-sparing surgery, renal function" identified in the Medline library were screened and data were extracted to perform a qualitative systematic review.

RESULTS

We identified 377 articles, 14 of which were integrated into the analysis. Data on 4288 children were included, 3994 (93.1%) underwent RN, whereas 294 (6.8%) underwent NSS. Stage I anatomopathology resulted in 55.1% RN and 79% NSS. Overall survival and event-free survival were similar: respectively 95.7% and 92.8% after RN and 96 and 90.5% after NSS. Positive margin status was higher after NSS (8.5% vs 0.5%), but tumor rupture and local tumor recurrences were similar. The rate of mild to moderate renal function was higher after RN (42% vs 10% after NSS).

DISCUSSION

NSS is regularly performed for WT in case of bilateral or syndromic tumors, but the literature considering UWT does not show consensus. The superiority of NSS for renal outcomes has now been fully evaluated, but the main problem of this surgery in case of UWT is to ensure oncologic outcomes as good as outcomes after RN. WTs are usually massive tumors for which partial nephrectomy is contraindicated, but studies showed that chemotherapy before surgery could reduce tumor volume and make NSS possible. This review shows that NSS results seem to be as good as RN results and that preoperative chemotherapy should be highlighted for its participation in the reduction of the positive margin status. Although radiotherapy is used with caution because of its side effects, some studies showed that it gave excellent results for oncologic salvage after local recurrence. Constant progress in medical imaging and detection systems has led to the emergence of a new type of assistance for surgeons such as image reconstruction and vessel or urinary tract system segmentation. Virtual simulation of the operation based on a real case should help evaluate the feasibility of complex procedures in the near future.

CONCLUSION

NSS for UWT seems to be a credible therapeutic alternative. New technologies such as 3D reconstruction should help surgeons define the best parameters to select ideal tumors for this surgery in the near future. For the moment, small tumors (<4cm), distant from the renal hilum (ideally on the upper pole) that respect at least 50% of the renal parenchyma (ideally superficial with exophytic development) seem to be the perfect indication for NSS.

Wilms tumor: Successes and challenges in management outside of cooperative clinical trials

OBJECTIVE/BACKGROUND

Management of Wilms tumor (WT) in children depends on a multidisciplinary approach to treatment, and outcomes have significantly improved as reported by cooperative group clinical trials. Here, we review the clinical outcomes of patients with WT and identify challenges and barriers encountered in multidisciplinary management outside of cooperative clinical trials.

METHODS

We retrospectively reviewed the clinical records of 35 children with WT treated between April 2002 and June 2013 at the Children's Cancer Institute in Lebanon.

RESULTS

Upfront resection was performed in 23 cases. Biopsies were performed for Stage V tumors (n=4), those with unresectable tumors or inferior vena caval thrombus (n=5), and patients who had partial surgery performed elsewhere prior to presentation (n=2). One patient died due to toxicity prior to surgery. The tumor was Stage I in eight patients, Stage II in five patients, Stages III and IV in nine patients each, and bilateral (Stage V) in four patients. Adherence to The National Wilms Tumor Study-5 recommendations was adequate. At the time of analysis, 30 patients were free of disease and four patients had relapse-all having metastatic disease initially.

CONCLUSION

The National Wilms Tumor Study-5 therapy resulted in favorable outcomes in children with nonmetastatic Wilms tumor in the setting of a multidisciplinary approach to therapy and resolution of financial barriers to medical care. Upstaging due to prior intervention and lung radiation therapy to all those with computed tomography-detected lung nodules may both have resulted in overtreatment of a subset of patients. Finally, the relatively high incidence of bilateral tumors suggests the need for further genetic and molecular studies in this patient population.

Wilms' tumor with intravascular extension: A review article

Intravascular extension of Wilms' tumor is a well-recognized phenomenon. Intravascular extension into the vena cava occurs in only 4-8% of patients with Wilms' tumors and intraatrial extension occurs in around 1-3% of patients. This review of the published literature in this cohort aims to summarize the findings of different case series to provide an optimum management plan. A literature search was performed and index papers were retrieved for review. The search included the following terms: Intracaval, intravascular, intraatrial and intracardiac extension of Wilms' tumor or nephroblastoma. The management of patients with intravascular tumor thrombus in Wilms' tumor is complex. A skilled multi-disciplinary team at a tertiary referral center with cardiothoracic surgery available should manage these patients. Multi-modal diagnostic and preoperative imaging are required to confirm and define the extent of the extension. Preoperative chemotherapy is advocated for all but exceptional circumstances and must be followed closely. Surgical resection should be planned according to the stage of intravascular extension with possible need for cardiopulmonary bypass and deep hypothermia with cardiac arrest if required. Surgical complications are more common in this group of patients, but outcome is comparable to those without intravascular extension, and is more closely correlated with the histological subtype then stage of intravascular extension. Operative imaging are required to confirm and define the extent of the extension.

Primary nephrectomy and intraoperative tumor spill: report from the Children's Oncology Group (COG) renal tumors committee

PURPOSE

Initial Children's Oncology Group (COG) management for Wilms' tumor (WT) consists of primary nephroureterectomy with lymph node sampling. While this provides accurate staging to define further treatment, it may result in intraoperative spill (IOS), which is associated with higher recurrence rates and therefore requires more intensive therapy. The purpose of this study is to determine current rates and identify factors which may predispose a patient to IOS.

METHODS

The study population was drawn from the AREN03B2 renal tumor banking and classification study of the Children's Oncology Group. All children with a first time occurrence of a renal mass were eligible for the study. At the time of enrollment and prior to risk stratification, the institution is required to submit operative notes, pathology specimens, a chest computed tomography scan (CT), and a contrast-enhanced CT or magnetic resonance imaging (MRI) of the abdomen and pelvis for central imaging review. These data are then used to determine an initial risk classification and therapeutic protocol eligibility. Patients who had a unilateral nephroureterectomy for favorable histology WT underwent further review to assure data accuracy and to clarify details regarding the spill. Analyses were performed using chi square and logistic regression. Odd ratios (OR) are shown with 95% confidence intervals.

RESULTS

There were 1,131 primary nephrectomies for unilateral WT with an IOS rate of 9.7% with an additional 1.8% having possible tumor spill during renal vein or IVC tumor thrombectomy. IOS correlated with diameter (>12 cm, p<0.0001) and laterality (right, p=0.0414). Simple logistic regression indicated that IOS increased 2.7% [p=0.0240, OR 1.027 (1.004, 1.052)] with each 1 cm increase in diameter (3 - 21 cm) and 4.7% [p=0.0147 OR 1.047 (1.009, 1.086)] with each 100 g increase in weight (80 - 1800 g). Multiple logistic regression indicated that laterality [right p=0.048, OR 1.46 (1.004, 2.110)] and weight (p=0.03, OR 1.039 (1.003, 1.075) were predictive of IOS when diameter was included as a continuous variable. Diameter as a binary variable was highly prognostic of IOS (p=0.0002), while laterality and weight were not significant.

CONCLUSIONS

Intraoperative tumor spill occurs in about one out of every ten cases of primary nephroureterectomies for WT. Right-sided and larger tumors are at higher risk of IOS.

Wilms' tumor

PURPOSE OF REVIEW

Wilms' tumor accounts for nearly 6% of all pediatric cancers and more than 95% of all kidney tumors in children. Fortunately, survival for patients with Wilms' tumor is generally excellent. This review will outline the results of prior clinical trials that have led to this excellent outcome and how information gleaned from these trials has led to the development of the current series of clinical trials for the management of children with Wilms' tumor.

RECENT FINDINGS

Tumor stage and histologic subtype have long been recognized as important prognostic factors in Wilms' tumor. More recent evidence suggests that, in certain instances, patient age, tumor size, response to therapy, and genetic abnormalities, specifically the loss of genetic material on chromosomes 1p and 16q, provide additional prognostic information. These factors have, therefore, been incorporated into a new risk stratification system that is currently being used to assign patients with Wilms' tumor to specific protocol-based therapies.

SUMMARY

Survival for patients with Wilms' tumor when considered as a whole, once less than 30%, is currently greater than 90%, with this dramatic improvement being due, in part, to the systematic manner in which the approach to therapy has evolved. Further refinement in therapy is being undertaken, with the current trials aiming to maintain the excellent survival for children being treated for Wilms' tumor, while minimizing therapy-related toxicity.

Pediatric genitourinary tumors

PURPOSE OF REVIEW

We will review the 2005 and 2006 literature on pediatric genitourinary tumors.

RECENT FINDINGS

Survival continues to improve for primary renal, bladder/prostate and testicular tumors in childhood. The addition of more intensive chemotherapy for anaplastic histology disease, recognition of loss of heterozygosity for chromosomes 1p and 16q as an adverse prognostic factor in favorable histology Wilms' tumor, and the utilization of molecular markers to better characterize all renal tumors will better enable individualized therapy. Recognition and treatment of anaplastic histology and bilateral Wilms' tumor remains a challenge. In rhabdomyosarcoma, genitourinary site and embryonal histology confer a relatively favorable prognosis.

SUMMARY

Advances in molecular oncology, diagnostic imaging, surgical approaches and long-term follow-up of childhood cancer survivors drive risk-stratified therapy in pediatric genitourinary tumors.