title: Relationship between quantitative tumor scintigraphy and time to metastasis in dogs with osteosarcoma.
abstract: Parameters that predict tumor aggressiveness or response to therapy are potentially useful in selecting the most appropriate treatment. In theory, the biologic aggressiveness of an untreated bone tumor may be reflected in bone scan parameters. The purpose of this study was to assess the usefulness of bone scintigraphy as a predictive indicator of subsequent metastasis in 25 dogs with primary osteosarcoma. Dogs received radiotherapy and/or intra-arterial cisplatin prior to limb-sparing surgery. Quantitative bone scintigraphy of the tumor was performed prior to treatment (25 dogs) and following treatment but prior to limb-sparing surgery (22 dogs). All dogs developed metastasis at a median time of 202 days (range, 41-444 days) after initiation of treatment. A statistically significant relationship was identified between time to metastasis and: (1) the radiographic tumor area, (2) the pretreatment ratio of mean counts per pixel in tumor-to-adjacent nontumor bone (T/NTT), and (3) the pre:post-treatment T/NTT. Larger tumor area and high pretreatment tumor activity were associated with earlier metastasis. Tumors characterized by greater decreases in scintigraphic uptake after treatment were associated with earlier metastasis. These data suggest that osteosarcomas with high pretreatment mean counts per pixel signify aggressive tumors subject to early metastasis.
authors.affiliation: College of Veterinary Medicine, North Carolina State University, Raleigh 27606.
authors.forename: L J
authors.initials: LJ
authors.lastname: Forrest
authors.forename: R K
authors.initials: RK
authors.lastname: Dodge
authors.forename: R L
authors.initials: RL
authors.lastname: Page
authors.forename: G L
authors.initials: GL
authors.lastname: Heidner
authors.forename: M C
authors.initials: MC
authors.lastname: McEntee
authors.forename: C A
authors.initials: CA
authors.lastname: Novotney
authors.forename: D E
authors.initials: DE
authors.lastname: Thrall
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000532:radiotherapy; D002945:Cisplatin / Q000008:administration & dosage / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D004285:Dogs; D007261:Infusions, Intra-Arterial; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local; D012516:Osteosarcoma / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000532:radiotherapy; D011877:Radionuclide Imaging; D013669:Technetium Tc 99m Medronate; D013997:Time Factors
chemical_list: D002945:Cisplatin; D013669:Technetium Tc 99m Medronate