Comparison of radioimmunotherapy and external beam radiotherapy in colon cancer xenografts

Journal Article · Mon Feb 15 04:00:00 EST 1993 · International Journal of Radiation Oncology, Biology and Physics; (United States)

DOI:https://doi.org/10.1016/0360-3016(93)90069-8· OSTI ID:6551176

Buras, R R; Wong, J F.C.; Kuhn, J A; Beatty, B G; Williams, L E; Beatty, J D ^[1]; Wanek, P M ^[2]

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1. City of Hope National Medical Center, Duarte, CA (United States)
2. Hybritech, Inc., San Diego, CA (United States)

Radioimmunotherapy and external beam radiotherapy were compared in a nude mouse human colon cancer model. Radioimmunotherapy was delivered by intraperitoneal injection of [sup 90]Y-labeled anticarcinoembryonic antigen monoclonal antibody (anti-CEA MAB). Single fraction external beam radiotherapy was delivered using a [sup 60]Co teletherapy unit. Control groups received saline, unlabeled anit-CEA monoclonal antibody and labeled nonspecific monoclonal antibody. Tumor growth suppression was expressed as delay to reach 2g compared to saline controls. Unlabeled anti-CEA monoclonal antibody and labeled nonspecific monoclonal antibody had no effect. External beam radiotherapy of 300, 600, 1000 and 2000 cGy produced growth delays of 3, 12, 17, and 22 days, respectively. Radioimmunotherapy with 120 [mu]Ci, 175 [mu]Ci, and 225 [mu]Ci resulted in growth delays of 20, 34, and 36 days. Estimated absorbed tumor dose was 1750 cGy in the 120 [mu]Ci group. Similar comparisons were done with the more radioresistant WiDr human colon carcinoma cell line. External beam radiotherapy doses of 400, 800, 1200, and 1600 cGy resulted in growth delays of 6, 21, 36 and 48 days, respectively. Radioimmunotherapy of 120 [mu]Ci and 175 [mu]Ci resulted in growth delays of 9 and 19 days, respectively. The 120 [mu]Ci dose delivered an estimated absorbed tumor dose of 1080 cGy to WiDr tumors. In summary, for the radiosensitive LS174T line, radioimmunotherapy produced biologic effects that were comparable to a similar dose of single fraction external beam radiotherapy. For the more radioresistant WiDr tumor, radioimmunotherapy produced a biologic effect which was less than a similar dose of single fraction external beam radiotherapy. These studies suggest that a tumor's response to radioimmunotherapy relative to that of external beam radiotherapy is, in part, dependent on tumor radiosensitivity and repair capacity. 23 refs., 5 figs. 4 tabs.

• OSTI ID: 6551176
• Journal Information: International Journal of Radiation Oncology, Biology and Physics; (United States), Journal Name: International Journal of Radiation Oncology, Biology and Physics; (United States) Vol. 25:3; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

560152* -- Radiation Effects on Animals-- Animals
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOLOGICAL EFFECTS
BIOLOGICAL MODELS
BIOLOGICAL RADIATION EFFECTS
COMPARATIVE EVALUATIONS
DISEASES
DOSES
EVALUATION
MEDICINE
NEOPLASMS
NUCLEAR MEDICINE
RADIATION DOSES
RADIATION EFFECTS
RADIOLOGY
RADIOTHERAPY
THERAPY
TIME DELAY