Paley's multiplier method does not accurately predict adult height in children with bone sarcoma.

BACKGROUND

The majority of patients with osteosarcoma and Ewing's sarcoma are diagnosed before skeletal maturity. Paley's multiplier is used for height prediction in healthy children, and has been suggested as a method to make growth predictions for children with osteosarcoma and Ewing's sarcoma when considering limb salvage options. To our knowledge, no evaluation of this method in this particular patient group has been performed, but a temporary growth deficit has been observed in children undergoing chemotherapy.

QUESTIONS/PURPOSES: We asked whether (1) Paley's formula reliably predicts growth in children who received polychemotherapy; (2) chemotherapy impairs growth velocity; and (3) final adult height is impaired in these patients.

METHODS

Retrospectively, data for 94 patients with osteosarcoma and Ewing's sarcoma were retrieved from databases of two sarcoma centers. Onset before 14 years of age in girls and 16 years in boys and a minimum followup until 18 years were required (mean, 67 months; range, 31-124 months) criteria. Exclusion criteria were the intake of growth hormones or no chemotherapy. Thirty-three patients (35%) fulfilled all inclusion criteria. Predicted adult heights were compared with actual adult height. The development of a growth deficit was evaluated for 23 children (without chemotherapy for recurrence) using age- and gender-specific standard deviation scores for height (WHO Z-scores).

RESULTS

Height prediction using Paley's method showed a high percentage of false predictions (outside ± 1 SD, 70%; outside ± 2 SD, 61%). On average, the mean total height of the patients was overestimated (2.3 cm). The median absolute error of prediction was 5.0 cm (range, -17 to 8). Patients with osteosarcoma and Ewing's sarcoma showed a significant growth impairment during polychemotherapy. A catchup phase in growth before skeletal maturity was observed in patients with osteosarcoma but not with Ewing's sarcoma.

CONCLUSIONS

Owing to its lack of reliability in this patient group, methods other than Paley's should be evaluated to predict adult height. Although limited by a small number of patients, our study results indicate a decreased adult height in patients with bone sarcoma after chemotherapy.

LEVEL OF EVIDENCE: Level III, therapeutic study. See the Instructions for Authors for complete description of levels of evidence.