Epidemiology of selected sarcomas in children

MicroRNAs for the pediatric otolaryngologist

The scope of pediatric otolaryngology is broad and encompasses a wide variety of diseases in which the fundamental phenotype-causing abnormality exists at the level of gene regulation and expression. Development of novel molecular biology instruments to diagnose disease, monitor treatment response, and prevent recurrence will facilitate the delivery of appropriate surgical and adjuvant medical treatments with lower morbidity. MicroRNAs (miRNAs) have emerged as a relatively new class of molecules that directly modulate gene expression and are abnormally expressed in a multitude of disease processes including those within the scope of pediatric otolaryngology. Functionally, miRNAs control multiple cellular functions including angiogenesis, cell proliferation, cell survival, genome stability, and inflammation. These short, non-protein coding RNA molecules are present and stable in tissue, blood, saliva, and urine, making them ideal disease biomarkers. The simple structure of miRNAs and their ability to directly modulate the expression of specific genes lends exciting therapeutic potential to miRNA-based therapies. Here we review the current literature of miRNAs as it relates to diseases within the scope of pediatric otolaryngology, and discuss their potential as diagnostic biomarkers and therapeutic targets.

Retroperitoneal sarcomas in children: outcomes from an institution

BACKGROUND

Retroperitoneal sarcomas are uncommon in children and tend to present as large tumors with advanced locoregional involvement of abdominopelvic structures. Surgical control of these tumors remains to be a management challenge. We reviewed our institutional experience with retroperitoneal sarcomas in children.

MATERIALS AND METHODS

In a retrospective review of charts dating between 1975 and 2005, we identified patients younger than 18 years who were diagnosed with a histologically confirmed retroperitoneal sarcoma. Patients were followed prospectively through clinic visits and mail correspondence. Standard statistical methods were used for comparative, risk, and survival analyses.

RESULTS

Twenty-one children with a mean age at presentation of 9 +/- 1 years were identified. There were more boys than girls (male/female ratio = 1.6). The most common presentations were abdominal mass/distention (76%) and pain (62%). The mean tumor size was 14.2 +/- 1.4 cm, with locoregional involvement in 62% of the patients. The common histologic types were rhabdomyosarcoma (33%) and fibrosarcoma (33%). Seventy-six percent of the patients underwent primary or secondary resection, 71% received neoadjuvant and/or adjuvant chemotherapy therapy, and 38% received radiation therapy. Complete resection was achieved in 48% of the patients, including 3 who required inferior vena cava resection and reconstruction. The 5-year disease-specific survival rates for patients who underwent complete resection and those who underwent incomplete resection were 90% and 36% (P = .018), respectively. For all patients, the mean survival time was 103 +/- 16 months and the 5-year disease-specific survival rate was 62%. Survival was significantly better for patients with low-grade sarcomas than for those with high-grade sarcomas (90% vs 36%, P = .008). Among those who underwent an initial complete resection, 50% had a recurrence at a mean time of 88 +/- 52 months (range = 3-261 months). The 30-day postoperative mortality and morbidity rates were 0% and 24%, respectively; in addition, 14% of the patients experienced long-term complications.

CONCLUSIONS

Resection of retroperitoneal sarcomas can be performed safely with minimal morbidity and mortality. Complete resection and low histologic grade are associated with significantly better disease-specific survival.

An estimate of the heritable fraction of childhood cancer

We have reviewed the records of the 16,564 cases of childhood cancer diagnosed from 1971 to 1983 which were reported to the National Registry of Childhood Tumours in Great Britain for the presence of underlying genetic disease in order to estimate the proportion which results from inherited mutations. A genetic condition was listed for 509 patients, or 3.07% of the total number of tumours. The most frequently recorded diagnoses were: bilateral retinoblastoma (162 cases); Down syndrome (135); neurofibromatosis (90); hereditary Wilms' tumour (71); and tuberous sclerosis (20). The highest hereditary fractions at individual tumour sites were seen for: retinoblastoma (37.2%); kidney (7.2%); leukaemia (2.6%) and brain and spinal cord (2.0%). When information about family history from published reports was incorporated into the figures calculated from Registry data the total genetic fraction was estimated to be 4.2%. We conclude that there is a clear genetic basis for a small minority of the cancers of childhood, but ethnic variation and the lack of known environmental determinants suggest that the total influence of heredity may be higher.

The epidemiology of cancer: an overview

The contribution of cancer epidemiology to cancer prevention is in identifying risk factors, providing clues for understanding etiologic mechanisms, and in developing the scientific rationale for the effective application of preventive measures. Cancer mortality, incidence, and survival trends over 25 years (1950-1974) in the United States are reviewed for 12 selected sites in adult men and women. If both incidence and mortality for a specific cancer site remain unchanged or change proportionately over a period of years, no major change in survival should be anticipated. The patterns of occurrence and their etiologic implications are reviewed separately in American blacks and in children and young adults. The studies of geographic pathology and of various migrant populations have provided observational "experiments of nature" that have facilitated our understanding of cancer etiology by stimulating important paths of research.

Childhood cancer in sibs

Thirty-eight families with cancer in two or more children were identified from records of the Sidney Farber Cancer Center and the Children's Hospital, Boston. Neoplasms developed in one pair of identical twins and in 37 sets of sibs (2 with 4 affected sibs, 4 with 3, and 31 sib-pairs). Predisposition to cancer extended to their parents and other relatives, and subsequently to other sibs who were unaffected at the time of ascertainment of the cancer-prone families. Genetic susceptibility was suggested in individual families by parental consanguinity or by an inherited disorder predisposing to cancer, but in other instances no oncogenic factors were identified. Familial aggregates of childhood provide opportunities for etiologic study and cancer control.

Blood-vessel neoplasms in children: epidemiologic aspects

In a search for etiologic leads to blood-vessel neoplasms, we examined 111 death certificates of U.S. children who died from 1960 to 1968 of angiosarcoma, hemangioendothelioma, and hemangiopericytoma and 127 medical records of similar cases from 12 institutes. The available data provided no leads to environmental agents (vinyl chloride, thorotrast, arsenic) that can produce vascular liver tumors in adults, but one infant, who died from a hepatic tumor, lived within a mile of an industrial source of polyvinyl chloride. About half of the children with hepatic hemangioendotheliomas had associated skin hemangiomas, which may aid in the differential diagnosis of liver tumors in infancy. Hepatic hemangioendotheliomas also predominated in girls, a possible clue to the origin of the tumor. A familial influence was suggested by one sibling aggregation of cutaneous hemangioendotheliomas.