Thallium-201 scintigraphy for the assessment of long-term prognosis in patients with osteosarcoma

Objective

The aim of this study was to confirm the prognostic value of ²⁰¹Tl scintigraphy in the midcourse of preoperative chemotherapy in patients with osteosarcoma.

Methods

The 28 patients with biopsy-proven osteosarcoma were enrolled retrospectively in this study. Planar scintigraphy was performed 15?min after injection of 111?MBq ²⁰¹Tl before preoperative chemotherapy and after third course (midcourse) of chemotherapy in all patients. The ²⁰¹Tl uptake ratio was calculated by dividing the count density of the lesion by that of the contralateral normal area. The percentage reduction of the ²⁰¹Tl uptake ratio calculated by 100?×?[(pre-chemotherapy ratio??C?mid-chemotherapy ratio)/pre-chemotherapy ratio] was compared with the histopathological response and long-term survival rate.

Results

Good histopathological response was observed in 16 patients. Mean follow-up period was 58.0?±?41?months. Both overall and event-free survival rates of histopathologically good responders were significantly higher than that of poor responders (P?=?0.018 and P?=?0.0076). There was also significant correlation between pre-chemotherapeutic effect evaluated with ²⁰¹Tl scintigraphy and overall and event-free survival rate in all patients (P?=?0.045 and P?=?0.017, respectively), and in patients without metastasis at initial diagnosis (P?=?0.043 and P?=?0.031, respectively).

Conclusion

²⁰¹Tl scintigraphy performed in the middle of neoadjuvant chemotherapy can predict overall survival and event-free survival in patients with osteosarcoma.