Solid pseudopapillary tumor of the pancreas (SPTP) is a rare neoplasm, predominantly affecting young females, with unclear pathogenesis and hormonal receptor (estrogen/progesterone receptor) expression potentially influencing tumor behavior. While surgical resection is the standard treatment, patients with advanced, metastatic, or recurrent disease lack effective therapies. Case reports suggest tamoxifen, a selective estrogen receptor modulator, may improve outcomes in hormone receptor-positive SPTP. This trial aims to evaluate tamoxifen's efficacy and safety in advanced SPTP.