Preoperative scintigraphy and operative probe scintimetry of colorectal carcinoma using technetium-99m-88BV59

We report a pilot study of radioimmunoscintigraphy (RIS) and operative gamma probe scintimetry (OPS) using a 99mTc-labeled anti-cytokeratin human monoclonal antibody (MAb) (99mTc-88BV59) in patients with newly diagnosed, recurrent or metastatic colorectal cancer.

Twelve presurgical patients with biopsy- or contrast radiographic-proven colorectal cancer or recurrent colorectal carcinoma were studied. After chest roentgenography and abdominopelvic CT, 99mTc-88BV59 was administered intravenously, planar and SPECT external imaging was performed 3 to 6 hr after injection and planar imaging was performed 18 to 24 hr after injection. Surgery was performed immediately after late planar imaging. OPS of a standardized list of sites to document background radiation activity and of tumor sites, resection margins and tumor beds was performed.

The patients had 23 histologically proven tumor sites. Overall sensitivity for CT, planar RIS, SPECT, surgery and OPS was 43%, 61%, 78%, 96% and 91%, respectively. SPECT was superior to CT for imaging extrahepatic abdominal and pelvic disease. OPS detected all liver and extrahepatic abdominal tumor sites and correctly predicted histological tumor-free margins and tumor beds in all cases. OPS did not identify tumor deposits that the surgeon could neither see nor feel. No patient demonstrated human anti-human immune responsiveness 1 and 3 mo after 99mTc-88BV59 infusion.

Technetium-99m-88BV59 is a safe, effective radioimmunoconjugate for colorectal cancer imaging, with superior sensitivity as compared to CT.