Recent experience with Wilms' tumor: 1978-1991

Long-term outcomes for infants with very low risk Wilms tumor treated with surgery alone in National Wilms Tumor Study-5

OBJECTIVE

To determine the event-free survival (EFS) and overall survival (OS) of children with very low risk Wilms tumor (VLRWT) treated with surgery only.

BACKGROUND

Previous studies suggested that postoperative chemotherapy had not improved the prognosis of children with VLRWT. A total of 77 children <24 months of age with small (<550 g) Stage I favorable histology Wilms tumors were treated with surgery only. This study was closed based on stopping rules to ensure that the 2-year EFS was > or =90%.

METHODS

A total of 77 children were assessed for EFS and OS. Of these patients, 21 enrolled at the time of closure were recalled, treated with dactinomycin and vincristine (regimen EE4A), and censored for analysis thereafter. About 111 children subsequently treated with EE4A were available for comparison.

RESULTS

Median follow-up of surviving patients was 8.2 years for surgery only (range, 1.9-11.8 years) and 5.2 years for the EE4A group (range, 1.6-8.9 years). The estimated 5-year EFS for surgery only was 84% (95% confidence interval [CI]: 73%, 91%); for the EE4A patients it was 97% (95% CI: 92%, 99%, P = 0.002). One death was observed in each treatment group. The estimated 5-year OS was 98% (95% CI: 87%, 99%) for surgery only and 99% (95% CI: 94%, 99%) for EE4A (P = 0.70).

CONCLUSION

The surgery-only EFS was lower than anticipated but, coupled with a much higher than anticipated salvage rate of the chemotherapy naive patients whose disease recurred, led to an observed long-term OS equivalent to that seen with 2-drug chemotherapy. This approach to the treatment of patients with VLRWT eliminates the toxic side-effects of chemotherapy for a large majority of patients. A follow-up study is underway to confirm these findings.

Prospects for the temporary treatment of acute liver failure

At present, the most successful treatment of acute liver failure is orthotopic liver transplantation, with survival rates ranging from 70% to 85%. However, mortality rates for liver failure remain high because of the shortage of available donor organs. Therefore, there has been renewed interest in temporary treatment methods for patients with acute liver failure to either allow liver regeneration or await liver transplantation. It is thought that the function of the liver can only be replaced with the biological substrate, e.g. liver cells or a whole liver specimen, which requires the availability of liver tissue from xenogeneic or human sources. In this review, existing temporary liver support techniques are summarized and the potential hazards are described. These include the immunological implications of these techniques, e.g. the host versus graft reaction, which may influence the effectivity of the support system, and in the long run may sensitize the patient to subsequent allogeneic transplantation. The graft versus host reaction is also considered. At present, one of the major concerns is the threat of pig-to-human transmission of activated endogenous retrovirus present in the pig genome. An overview is given of literature concerning the transmission of retrovirus particles in vitro and in vivo. Finally, new solutions for the development of ex vivo systems for temporary treatment of patients with acute liver failure are discussed. These include the use of new immortalized human cell lines and human fetal hepatocytes, and the possibility of isolating, expanding and genetically manipulating stem cells in order to have stable differentiated and committed cells.

Extracorporeal perfusion for the treatment of acute liver failure

OBJECTIVE AND SUMMARY BACKGROUND DATA

Because of the shortage of available donor organs, death rates from liver failure remain high. Therefore, several temporary liver-assisting therapies have been developed. This article reviews various approaches to temporary liver support as well as immunologic and metabolic developments toward a solution for this problem.

METHODS

A literature review was performed using Medline and additional library searches to obtain further references. Only articles with a well-defined aim of study and methodology and a clear description of the outcome of the experiments were included.

CONCLUSIONS

Renewed interest has developed in old and new methods for an extracorporeal approach to the treatment of acute liver failure. Although temporary clinical improvement has been established, further research is needed to achieve a successful long-term clinical outcome. New developments in the field of genetic modification and tissue engineering await clinical application in the near future.

Pediatric renal tumors

A broad spectrum of renal tumors occurs in infants and children ranging from the benign cystic nephroma to the extremely aggressive malignant rhabdoid tumor of the kidney. A thorough understanding of these tumors is crucial to the optimal diagnosis and management of children with renal masses. The common renal tumors in infants and children are discussed and an orderly method for their evaluation is presented. Recent developments in the molecular biology of Wilms' tumor are outlined to provide insight into the origin of this tumor.