Rare childhood tumors in a Turkish pediatric oncology center

Abstract

Background:It has been estimated that rare tumor rate is about 15% of all childhood cancer in United States. According to Turkish Pediatric Oncology Group (TPOG) datas, 8889 children were diagnosed between 2002 and 2008 in our country and 3.7% of them were diagnosed as rare tumors.Aim:To investigate the frequency and clinical features of rare tumors in our pediatric oncology center.Materials and Methods:A total of 43 cases that have diagnosed as rare tumor in 574 cancer patients between the yaer 2002 and 2012 were reviewed retrospectively. All cases definitive diagnosis were established by histopathological and immunohistochemical studies.Results:Frequency of rare tumors was 7.4% in our center. Benign and border line rare tumors were 27 (62.7%) cases, malignant rare tumor were 16 (37.2%) cases. Median follow-up period was 48 months (between 1 and 110 months). Six of the malignant rare tumors were died with progressive disease (synovial sarcoma, mixed malignant mesenchymal tumor, undifferentiated sarcoma, plexus choroideus carcinoma, renal peripheral primitive neuroectodermal tumor, adrenocortical carcinoma). Malignant rare tumor mortality rate was found 37.5% in our clinic.Conclusion:We have found that our rare tumor rate (7.4%) was higher than Turkish rare tumor rate (3.7%) according to TPOG's datas. However, it was still lower than rare tumor rates of western countries (15%), probably due to difficulties of diagnosis and referral problems.

Rare cancers

“…Another study28 also reported that most frequent cancer forms among adolescents in their rare tumour cases were thyroid carcinomas (11.6%) as shown in TREP list. Although incidence seldom exceeds 1.5/million, the most common carcinoma in children is the thyroid carcinoma in many regions of the world74.…”

“…Considering this situation in children, the UK Children's Cancer Study Group and the US Children's Oncology Guidelines suggest annually thyroid palpation, followed by ultrasound or fine needle aspiration if there is an abnormality75. Tacyildiz et al 28 have explained most of the rare malignant, borderline and benign tumour types among children and adolescents in their study.…”

“…Most rare cancer epidemiology studies involve people living in Europe 1 5 8 23 , North America 4 , Australia 24 , Japan 25 , Italy 5 26 27 , Turkey 28 , etc ., which constitute a small portion of the global population. Definite descriptions of such data from other countries are still limited mainly because of the uncertainty in the definition of rare cancers.…”

“…Cancer incidence and survival data have indicated that rare cancer incidence rate is about 15 per cent of all childhood tumour in the US 72 . Turkish Pediatric Oncology Group (TPOG) observed that 8889 children were diagnosed with cancers between 2002 and 2008 in their country and 3.7 per cent of them were diagnosed as rare cancers 28 .…”

“…Pleuropulmonary blastoma and other lung tumours, nasopharyngeal carcinoma, adrenocortical tumours, renal carcinoma, thyroid carcinoma, breast carcinoma, carcinoid tumours, cutaneous melanoma, salivary gland tumours, gastrointestinal tract carcinoma, gonadal non-germ cell tumours (ovary/testis), pheochromocytoma, paraganglioma, pancreatoblastoma and other pancreatic exocrine and thymus carcinoma were enrolled in their study group 26 27 73 . TPOG study list was different from TREP list and included the rare cases such as hepatoblastoma, renal primitive neuroectodermal tumour, adrenocortical carcinoma and synovial sarcoma 28 .…”