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 1 980 and 1991 in our Institution with surgery only (35 cases), surgery combined with adjuvant chemotherapy (147 cases) or neoadjuvant chemoth erapy (363 cases) the relapse patterns were analyzed. Adjuvant chemoth erapy was performed according to 2 different protocols and neoadjuvant chemotherapy according to 3 different protocols successively activate d. In the 252 patients who relapsed, the interval between initial trea tment 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 wit h neoadjuvant chemotherapy, a longer interval was seen in the most eff ective regimen of neoadjuvant chemotherapy (25 mo). No significant dif ferences were seen among the 3 groups, according to the site of first metastasis, although in patients treated with the most effective neoad juvant regimen there was a higher incidence of bone metastasis. In pat ients who relapsed with pulmonary metastases the average number of nod ules seen by standard X-rays, as well as CT scans, was significantly h igher in patients treated with surgery only (3.6) than in patients tre ated with adjuvant or neoadjuvant chemotherapy (2.5 and 2.6 nodules). We conclude that these changes in metastatic pattern in patients treat ed with adjuvant and neoadjuvant chemotherapy are important, because t hey may encourage the use of salvage therapy with thoracotomy in a lar ger number of patients. Prolongation of time relapsed after more effec tive regimens of adjuvant and neoadjuvant chemotherapy should be consi dered when evaluating the preliminary results of new chemotherapy prot ocols.