[Evaluation of images of periosteum on computed tomography in children with malignant bone tumours before and after chemotherapy].
OBJECTIVE
to assess the value of different images of periosteal reaction on computed tomography (CT) in children with malignant bone tumours in determining the effectiveness of the chemotherapy. To evaluate the prognostic value of particular symptoms of the periosteal reaction.


METHODS
material includes documentation of CT imaging of periosteum in children with malignant bone tumours. Investigations were performed in 80 children (39 boys and 41 girls), aged from 3 years and 6 months to 20 years and 5 months, treated at the Institute of Mother and Child in the years 1995-2000. Osteogenic sarcoma (59 patients), Ewing's sarcoma/PNET (14 patients) and other mesenchymal tumours (7 patients) were diagnosed. The assessment of the periosteum was carried out before and after preliminary chemotherapy. Eleven symptoms of the periosteal reaction were distinguished: 1) changes in calcification, 2) thickness and 3) outlines of the periosteum, 4) change of number of stratifications, 5) reconstruction of the broken periosteum and 6) rebuilding of the Codman's triangle, 7) changes of calcification, 8) incorporation and 9) the number of spicules as well as 10) changes in the zone of unreactive areas and 11) distance from the periosteum to the bones. Each symptom was evaluated according to a three-grade scale: favourable, uncertain, unfavourable. The kind of response to chemotherapy was determined on the basis of these symptoms relations. The response was good if there were at least twice as many favourable as uncertain signs. Poor response was indicated if there were more uncertain than favourable symptoms or if an unfavourable symptom was found. The remaining situations accounted for medium response. CT scan assessment was compared with the tumour histopathological examination after surgical excision. The data underwent statistical analysis.


RESULTS
the relationship of symptoms of the periosteal reaction and histopathological response to chemotherapy was determined. Assessment of tumour reaction to chemotherapy based on own system of evaluation was in agreement with the histopathological results in 96.9% in the group of good responses (31/32), in 66.7% in group of medium responses (10/15) and in 87.9% in the group of poor responses (29/33), (dSomers coefficient 0.840, chi2 v=100.739 df=4 p<0.001).


CONCLUSIONS
1. The author's own scheme of evaluation of periosteal reactions on CT provides good correlation and concordance with the histopathological assessment of the kind of response to chemotherapy in children with malignant bone tumours. 2. Analysis of manifestations of periosteal reaction on CT demonstrates full prognostic conformity of the so-called unfavourable symptoms to findings of the histopathological examination in the estimation of poor response. 3. Favourable periosteal reactions are found in all types of response, but three of them, i.e. reduced number of periosteal proliferations, total reconstruction of the broken periosteum and total rebuilding of the Codman's triangle, show significant frequency only in cases of good response. 4. Uncertain symptoms: unchanged periosteal thickness, lack of incorporation of spicules, decreased of number of unincorporated spicules, increased or unchanged size of unreactive (uncalcified and necrotic) areas - did not appear in cases of good response. They were found in medium and poor responses, which supports the suggestion of excluding the so-called medium response from the criteria of response assessment. 5. Decreased size of the tumour (i.e. distance between periosteum and bone) appears in all types of response to chemotherapy and it cannot be regarded as a manifestation of good response. 6. Own system of evaluation of tumour response to chemotherapy, based on the relationship manifestations of periosteal reaction is confirmed by statistical analysis.
Kopys-Wiszniewska
Izabela
I
Zaklad Diagnostyki Obrazowej, Instytut Matki i Dziecka, ul. Kasprzaka 17a, Warszawa, Poland. Zaklad.rtg@imid.med.pl
D000293:Adolescent; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D012516:Osteosarcoma / Q000000981:diagnostic imaging* / Q000188:drug therapy; D010521:Periosteum / Q000000981:diagnostic imaging* / Q000187:drug effects* / Q000473:pathology; D011044:Poland; D011379:Prognosis; D012189:Retrospective Studies; D012512:Sarcoma, Ewing / Q000188:drug therapy; D014057:Tomography, X-Ray Computed