CHANGING PATTERN OF RELAPSE IN OSTEOSARCOMA OF THE EXTREMITIES TREATED WITH ADJUVANT AND NEOADJUVANT CHEMOTHERAPY

In 551 patients with osteosarcoma of the extremities treated between 1980 and 1991 in our Institution with surgery only (35 cases), surgery combined with adjuvant chemotherapy (147 cases) or neoadjuvant chemotherapy (363 cases) the relapse patterns were analyzed. Adjuvant chemotherapy was performed according to 2 different protocols and neoadjuvant chemotherapy according to 3 different protocols successively activated. In the 252 patients who relapsed, the interval between initial treatment and first relapse was significantly longer in the group treated with adjuvant and neoadjuvant chemotherapy (18.1 and 21.3 mo) than in the group treated with surgery only (5.4 mo). For patients treated with neoadjuvant chemotherapy, a longer interval was seen in the most effective regimen of neoadjuvant chemotherapy (25 mo). No significant differences were seen among the 3 groups, according to the site of first metastasis, although in patients treated with the most effective neoadjuvant regimen there was a higher incidence of bone metastasis. In patients who relapsed with pulmonary metastases the average number of nodules seen by standard X-rays, as well as CT scans, was significantly higher in patients treated with surgery only (3.6) than in patients treated with adjuvant or neoadjuvant chemotherapy (2.5 and 2.6 nodules). We conclude that these changes in metastatic pattern in patients treated with adjuvant and neoadjuvant chemotherapy are important, because they may encourage the use of salvage therapy with thoracotomy in a larger number of patients. Prolongation of time relapsed after more effective regimens of adjuvant and neoadjuvant chemotherapy should be considered when evaluating the preliminary results of new chemotherapy protocols.