In an analysis from the Children’s Oncology Group study AHEP0731 reported in the Journal of Clinical Oncology, Trobaugh-Lotrario et al found that the presence of small cell undifferentiated histology elements did not appear to adversely affect outcomes in pediatric patients with hepatoblastoma.
Study Details
In the study, patient tumors underwent institutional and central pathologic review for identification of small cell undifferentiated histology. Patients with small cell undifferentiated histology identified at local treating institutions who otherwise had low-risk tumors were upstaged to the intermediate-risk treatment stratum; those identified only by retrospective central review were treated as low-risk based on local institution review. Treatment according to risk strata was based on local review; analysis of outcomes was based on central review.
Key Findings
The analysis included 185 patients, with 35 having some elements (1%–25%) of small cell undifferentiated identified on central review. All but two patient samples retained nuclear INI1 expression. Presence of small cell undifferentiated histology was not associated with age, alpha-fetoprotein level at diagnosis, or sex.
Among the 185 patients:
- 8 non–small cell undifferentiated vs 0 small cell undifferentiated patients were classified as very low–risk
- 42 non–small cell undifferentiated vs 7 small cell undifferentiated patients were classified as low-risk
- 79 non–small cell undifferentiated vs 21 small cell undifferentiated patients were classified as intermediate-risk
- 21 non–small cell undifferentiated vs 7 small cell undifferentiated patients were classified as high risk.
The presence of small cell undifferentiated elements was not significantly associated with event-free survival after adjustment for treatment (P = .17). Among all small cell undifferentiated vs all non–small cell undifferentiated patients, 5-year event-free survival was 71% (95% confidence interval [CI] = 53%–83%) vs 83% (95% CI = 76%–89%). Among small cell undifferentiated patients, rates were 86% (95% CI = 33%–98%), 81% (95% CI = 57%–92%), and 29% (95% CI = 4%–61%) for low-, intermediate-, and high-risk tumors, respectively. Among non–small cell undifferentiated patients, rates were 87% (95% CI = 72%–95%), 88% (95% CI = 79%–94%), and 55% (95% CI = 32%–74%) for low-, intermediate-, and high-risk tumors.
Among all patients, 5-year overall survival was 86% (95% CI = 69%–94%) among small cell undifferentiated patients vs 90% (95% CI = 83%–94%) among non–small cell undifferentiated patients. Among small cell undifferentiated patients, rates were 100%, 86% (95% CI = 62%–95%), and 71% (95% CI = 26%–92%) for low-, intermediate-, and high-risk tumors. Among non–small cell undifferentiated patients, rates were 92% (95% CI = 78%–97%), 95% (95% CI = 87%–98%), and 64% (95% CI = 39%–81%), for low-, intermediate-, and high-risk tumors.
The investigators concluded, “The presence of small cell undifferentiated histology in hepatoblastoma does not appear to adversely affect outcome. Future studies should be able to treat patients with small cell undifferentiated hepatoblastoma according to risk stratification without regard to the presence of small cell undifferentiated histology.”
Howard M. Katzenstein, MD, of Nemours Children’s Specialty Care and Wolfson Children’s Hospital, Jacksonville, Florida, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by grants from the National Cancer Institute, St. Baldrick’s Foundation, and others. For full disclosures of the study authors, visit ascopubs.org.
