7.P.31 P53 IMPORTANCE IN THE DETERMINATION OF MEDICAMENTAL RESISTANCE OF OSTEOGENOUS SARCOMA OF LOWER EXTREMITIES LONG BONES IN CHILDREN

Abstract

It has been determined the prognostic importance of P-53 suppressor in 26 patients with osteogenous sarcoma of long tubular bones of lower extremities. Tumour localized in femoral bone in 14 observations (53,9%), in shin bone-11 (42,2%) and in fibular bone-1 (3,9%).

According to methods of treatment, all patients were divided into two groups:

• I group: 18 patients received chemical and beam therapy. Treatment in this group was carried out by following scheme: intraneous metrotrexat, 25 mg/kg for 24 hours with leucovorin, intraneous cisplatin, 100 mg/m² for 4 hours. OOD-2,2Gy, SOD 60Gy beam therapy (telegammatherapy) was conducted after 4 courses of chemotherapy, 5 courses of chemotherapy by above-mentioned scheme was made after the end of beam therapy course.

• II group: 8 patients received chemo-beam therapy + operation + chemotherapy by scheme: intraneous doxorubicine, 60 mg/m² for 48 hours, cisplatin, 100 mg/m² for 4 hours on the 3 day, 4 courses with the interval of 3 weeks. After 4 courses of chemotherapy ROD − 2,2Gy, SOD 60Gy beam therapy was made. Subsequently after operation 5 patients received 5 courses of adjuvant chemotherapy.

Of 26 patients in 2 (7,8%) was noted complete effect, in 16 (61,5%) – partially effect, in 2 (7,8%) – stabilization of the process and in 6 (22,9%) – tumour progressing.

To estimate study results and determination of medicamental resistance of sarcoma there studied the rates of P-53 suppressor, as study results showed, in 6 (23%) observed moderate or high P-53 suppressor expression in tumor cells, and in 20 (77%) cases did negative and low-positive tumor or low negative and immunohistochemical tumor response. There established that low rates of P-53 suppressor correlated with high sensitivity of tumor to chemo-beam therapy, otherwise there obtained reverse reaction.

Conclusions: study results showed that P-53 suppressor rates have a significant importance in the determination of treatment strategy, tumor sensitivity to chemo-beam therapy and clinical outcome.