Relative tumor burden predicts metastasis-free survival in pediatric osteosarcoma.
BACKGROUND
To analyze the significance of relative tumor burden in pediatric osteosarcoma.


METHODS
We retrospectively reviewed 241 patients with localized pediatric osteosarcoma and measured tumor size on MR images at presentation. Absolute tumor size parameters measured on MR images were converted to relative values by dividing body surface area. Both absolute and relative size parameters were analyzed for their correlation with metastasis-free survival (MFS).


RESULTS
The 5-year MFS was 67.5 +/- 3.1%, with median follow-up of 72 months (range, 8-205 months). In addition to poor histologic response (RR 3.24; 95% CI: 1.99-5.28; P < 0.001), large relative tumor plane (RTP; RR 3.28; 95% CI: 1.72-6.25; P < 0.001), large relative tumor area (RTA; RR 4.14; 95% CI: 1.53-11.22; P = 0.005), and large absolute tumor width (ATW; RR; 3.10; 95% CI: 1.23-7.79; P = 0.02) shortened the MFS. When survival was analyzed by combining RTP and histologic response, patients with small RTP and a good response showed the best survival (5-year MFS of 90.2 +/- 3.6%), while those with large RTP and a poor response showed the worst survival (5-year MFS of 45.1 +/- 6.6%).


CONCLUSIONS
Relative two-dimensional tumor size parameters (RTP and RTA) rather than absolute values are useful prognostic factors in pediatric osteosarcoma patients.
Department of Pediatrics, Korea Cancer Center Hospital, Seoul, Republic of Korea.
Jun Ah
JA
Lee
Min Suk
MS
Kim
Dong Ho
DH
Kim
Jung Sub
JS
Lim
Ji Young
JY
Yoo
Jae Soo
JS
Koh
Soo-Yong
SY
Lee
Dae-Geun
DG
Jeon
Kyung Duk
KD
Park
D000293:Adolescent; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D017024:Chemotherapy, Adjuvant; D002648:Child; D002675:Child, Preschool; D002945:Cisplatin / Q000008:administration & dosage; D018572:Disease-Free Survival; D004317:Doxorubicin / Q000008:administration & dosage; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging; D008297:Male; D008727:Methotrexate / Q000008:administration & dosage; D020360:Neoadjuvant Therapy; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D012516:Osteosarcoma / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D011379:Prognosis; D011877:Radionuclide Imaging; D012189:Retrospective Studies
D004317:Doxorubicin; D002945:Cisplatin; D008727:Methotrexate