Soft tissue sarcomas of childhood and adolescence: the prognostic role of tumor size in relation to patient body size.
OBJECTIVE
Tumor size is a key prognostic variable for soft tissue sarcomas (STS), and a tumor diameter of 5 cm is generally used as a cutoff for risk grouping purposes. This study aimed to investigate the prognostic effect of tumor size on overall survival and whether such an effect was influenced by the patient's size, expressed as body-surface area (BSA), in a series of 553 pediatric patients with localized STS.


METHODS
Multivariable Cox models were used in which the effect of tumor size was adjusted for patients age, tumor site, histologic subtype, and Intergroup Rhabdomyosarcoma Study grouping, and the interaction between size and BSA was included.


RESULTS
Tumor size was confirmed as a significant prognostic factor. Interaction between size and BSA meant that, for a given tumor size, the mortality increased from the larger to the smaller BSA. Conversely, the mortality risk associated with a patient with a BSA of 1.75 m(2) and a 5-cm tumor was the same as for a 0.6 m(2) child with a 2.8-cm tumor.


CONCLUSIONS
Tumor and body size are jointly informative on outcome. The risk associated with a given tumor size is not the same in patients of different body size, so it may be wrong to use the same 5-cm cutoff for tumor size in risk stratification.
Ferrari
Andrea
A
Pediatric Oncology Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Istituto Nazionale Tumori, Milano, Italy. andrea.ferrari@istitutotumori.mi.it
Miceli
Rosalba
R
Meazza
Cristina
C
Zaffignani
Elena
E
Gronchi
Alessandro
A
Piva
Luigi
L
Collini
Paola
P
Podda
Marta
M
Massimino
Maura
M
Luksch
Roberto
R
Cefalo
Graziella
G
Terenziani
Monica
M
Spreafico
Filippo
F
Polastri
Daniela
D
Fossati-Bellani
Franca
F
Casanova
Michela
M
Mariani
Luigi
L
D000293:Adolescent; D001830:Body Surface Area; D002648:Child; D006801:Humans; D011379:Prognosis; D016016:Proportional Hazards Models; D012509:Sarcoma / Q000401:mortality* / Q000473:pathology*; D012983:Soft Tissue Neoplasms / Q000401:mortality* / Q000473:pathology*; D015996:Survival Rate; D055815:Young Adult