prostate cancer,psa low,-why is this cea high

hi folks, i'm 75.severe backpain led to hospitilisation,discovery of enlarged prostate,with mri/niclear scans indicating malignant lesions on spine vertibrae,followed by prostate and hip bone (ileum) biopsies which confirmed prostate cancer metastised to bone. psa below 3.o. cea 10.. gleason 3 plus 4.all this in feb 2008.my oncologist assumed it to be a prostate primary. performed an orchidectomy. psa fell to below .3 in a week. backpain reduced by 60 %. doctor put me on a tab, once a day-bicalutamide 50 mg. he sent me home. said review after a month.my backache increased. the oncologist had my prostate and hip bone biopsy material compared by pathology lab. they said the two malignant species were different!!! threw us all into so...