Ewing's sarcoma as second malignancy following a short latency in unilateral retinoblastoma

Subsequent Malignant Neoplasm of Bone in Children and Adolescent—Possibility of Multimodal Treatment

Background: In recent years, modifications of treatment protocols introduced in pediatric oncology have resulted in a significant improvement in treatment outcomes. Unfortunately, the probability of subsequent malignant neoplasm (SMN) in this group of patients is 3 to 6 times higher than the general age-matched population. In this study, we sought to evaluate the treatment options for patients with secondary bone tumors after prior anti-cancer therapy. Materials and Methods: Twenty-four patients (median age 12.9 years) with subsequent malignant bone tumors were treated according to oncological guidelines for bone sarcoma during the period 1991–2020. All patients had a standard tumor imaging and laboratory evaluation. All toxicities were documented. Results: The median time from the first neoplasm to SMN was 7.6 years (range 2.4 to 16.3 years). All patients received chemotherapy and underwent surgery as a local control procedure. Two patients with Ewing sarcoma had additional radiation on the tumor bed. A complete response was achieved in 20 patients. With a median follow-up of 18.3 years (range 5.7 to 40.3 years), 18 patients (75%) are alive. The estimated 5-year post-subsequent bone malignant neoplasm survival was 74.5% (95% CI 55–95%). Fourteen patients required chemotherapy dose modification, and doxorubicin was discontinued in seven patients. One patient required a renal transplant two years after treatment. There were no other significant toxicities. Conclusions: The treatment of bone SMNs can be effective, although in many patients it is necessary to reduce the doses of drugs. Early detection and aggressive treatment can improve the outcome.

Germline Mutations in Predisposition Genes in Pediatric Cancer

BACKGROUND

The prevalence and spectrum of predisposing mutations among children and adolescents with cancer are largely unknown. Knowledge of such mutations may improve the understanding of tumorigenesis, direct patient care, and enable genetic counseling of patients and families.

METHODS

In 1120 patients younger than 20 years of age, we sequenced the whole genomes (in 595 patients), whole exomes (in 456), or both (in 69). We analyzed the DNA sequences of 565 genes, including 60 that have been associated with autosomal dominant cancer-predisposition syndromes, for the presence of germline mutations. The pathogenicity of the mutations was determined by a panel of medical experts with the use of cancer-specific and locus-specific genetic databases, the medical literature, computational predictions, and second hits identified in the tumor genome. The same approach was used to analyze data from 966 persons who did not have known cancer in the 1000 Genomes Project, and a similar approach was used to analyze data from an autism study (from 515 persons with autism and 208 persons without autism).

RESULTS

Mutations that were deemed to be pathogenic or probably pathogenic were identified in 95 patients with cancer (8.5%), as compared with 1.1% of the persons in the 1000 Genomes Project and 0.6% of the participants in the autism study. The most commonly mutated genes in the affected patients were TP53 (in 50 patients), APC (in 6), BRCA2 (in 6), NF1 (in 4), PMS2 (in 4), RB1 (in 3), and RUNX1 (in 3). A total of 18 additional patients had protein-truncating mutations in tumor-suppressor genes. Of the 58 patients with a predisposing mutation and available information on family history, 23 (40%) had a family history of cancer.

CONCLUSIONS

Germline mutations in cancer-predisposing genes were identified in 8.5% of the children and adolescents with cancer. Family history did not predict the presence of an underlying predisposition syndrome in most patients. (Funded by the American Lebanese Syrian Associated Charities and the National Cancer Institute.).