Osteosarcoma is the most common primary bone malignancy in childhood and adolescence. Its peak age of onset has suggested a possible contribution to the pathogenesis of the tumor by the endogenous hormonal milieu, which accompanies the adolescent growth spurt. In support of this, recent in vitro and in vivo laboratory investigators suggest that Insulin-like growth factor I (IGF I) may play an important role in the pathobiology of osteosarcoma. Somatostatin (and its longer-acting analogues) directly inhibits the pituitary release of growth hormone, thereby indirectly reducing the level of circulating IGF I. Other data have also demonstrated that the anti-estrogen, tamoxifen, significantly reduced circulating IGF I levels. We propose to administer the long acting somatostatin analog, OncoLAR® (Registered Trademark), alone and in combination with tamoxifen in patients with osteosarcoma. The degree of suppression of both circulating IGF I and growth hormone levels will be determined at two dose levels of OncoLAR® (Registered Trademark) alone and in combination with tamoxifen to determine whether the addition of tamoxifen to OncoLAR® (Registered Trademark) leads to significant additional reduction in circulating IGF I and growth hormone levels.