Radioimmunolocalization and selection for surgery in recurrent colorectal cancer

Abstract

The value of radioimmunolocalization (RIL) of cancer depends on its performance in situations where the result determines the choice of management. A rise in serum carcinoembryonic antigen (CEA) values after apparently curative resection of colorectal cancer implies localized, resectable recurrence in some patients and widespread unresectable tumour in others. This study investigated the ability of RIL with radiolabelled antibody to CEA and a novel numerical method for analysis of results to determine the extent of disease in 31 patients with raised serum CEA but no physical signs of recurrence. Surgical exploration or conventional radiology later confirmed the presence of tumour in 94 per cent of sites which were positive by RIL. Negative RIL predicted the absence of disease in 53 per cent of patients. The investigation could discriminate between localized and disseminated disease and often performed better than conventional radiology. RIL appears useful in selection of patients for second look laparotomy.

Factors influencing variability of localisation of antibodies to carcinoembryonic antigen (CEA) in patients with colorectal carcinoma – implications for radioimmunotherapy

“…Antibody uptake in thyroid was blocked by administration of potassium iodide and potassium perchlorate. Patients were tested for skin allergy as previously described (Begent et al, 1986). 0.4 mg of IgGI mouse monoclonal antibody (A5B7) to CEA (Harwood et al, 1986) (Pedley et al, 1987).…”

In vivo studies on the uptake of radiolabelled antibodies by colorectal and gastric carcinoma xenografts

“…In this study we have therefore compared the uptake of antibodies to different CEA epitopes by HT29 xenografts to determine whether any one antibody shows increased uptake over any of the others. One of these antibodies 11-285-14 has already been shown to localise tumours in both humans [1,3] and animals [16]. Of the other antibodies studied, only 14-95-55 has been shown to behave in a similar manner to 11-285-14 but the localising ability is not superior.…”

Preparation and properties of a mouse monoclonal antibody (W14A) to human chorionic gonadotropin

“…There are inherent limitations in the subtraction technique (Begent, 1983) and it cannot be stated categorically that there is no unwanted localization, but judging by the positive accumulation of antibody in defined tumour sites summarized in Table 111, the W14A reagent is at least comparable to the polyclonal antiserum previously employed.…”

“…There are no indications, in the five patients so far investigated, of unexpectedly high localization of the monoclonal antibody in any normal organ to a greater extent than that encountered with the polyclonal antibody previously used (results not shown). There are inherent limitations in the subtraction technique (Begent, 1983) and it cannot be stated categorically that there is no unwanted localization, but judging by the positive accumulation of antibody in defined tumour sites summarized in Table 111, the W14A reagent is at least comparable to the polyclonal antiserum previously employed.…”