Benefits of radioimmunoguided surgery for pelvic recurrence.

AIM: Surgery for recurrent rectal cancer is usually traumatic and of questionable curative value. The use of radioimmunoguided surgery (RIGS) in enhancing the surgeon's assessment of the extent of disease in these patients was investigated. METHODS: Twenty-one patients diagnosed with recurrent pelvic cancer were operated using the RIGS(O)system. Preoperative assessment included CTs of chest, abdomen and pelvis as well as colonoscopy. Patients were injected with CC49, a monoclonal antibody (MoAb) labelled with 125I. Surgical exploration was followed by survey with the gamma-detecting probe. RESULTS: Surgical exploration identified eight intra-colorectal recurrences, nine extra-colonic pelvic recurrences and five extra-pelvic lymph node metastases. RIGS exploration confirmed all intra-colonic recurrences except for one (patient with no MoAb localization), identified 13 pelvic recurrences and 10 lymph node metastases. There were seven patients with occult findings (33%), resulting in a modified surgical procedure. Surgery included five abdomino-perineal resections, six low anterior resections, seven excisions of presacral tumour, eight total abdominal hysterectomy and bilateral salpingo-oophorectomy, one pelvic exenteration and one post-exenteration. There were no operative deaths. Eight patients had minor complications, and one patient had a major complication with reoperation due to urinary leak. The mean follow-up was 18 months. Ten patients died of disease. CONCLUSION: Although not curative, RIGS can help the surgeon in the decision-making process through better disease staging.

Immunoguided lymph node dissection in colorectal cancer: a new challenge?

Knowledge of lymphatic involvement in patients with colorectal cancer is important in surgery and in the postoperative decision-making process. Fifty-eight patients with recurrent colorectal cancer underwent operation with the RIGS/(Radioimmunoguided Surgery) technology. Preoperatively, patients were injected with 1 mg monoclonal antibody (MoAb) CC49 (anti-TAG-72-tumor-associated glycoprotein) labeled with 2 mCi of iodine 125. Traditional surgical exploration was followed by survey with a gamma-detecting probe. Localization of MoAb on tumor was noted in 54/58 patients (93%). Traditional exploration identified 117 suspected tumor sites. With RIGS, 177 suspected tumor sites were detected. In 17 of the 58 patients (27.5%), at least one occult tumor site identified by RIGS was confirmed by pathology with hematoxylin & eosin (H & E) staining. This finding resulted in 16 major changes in surgical plan. RIGS performance varied between lymphatic and non-lymphatic tissue, with a positive predictive value (PPV) of 95.6% and negative predictive value (NPV) of 90% in non-lymphoid tissue compared to PPV of 40% and NPV of 100% in lymphoid tissue. In patients with tumors that localize, no RIGS activity in lymph nodes signifies no tumor, while decisions based on RIGS activity in lymph nodes requires H & E confirmation. Using this guideline, additional information acquired by RIGS can help the surgeon in making an informed decision during surgery and in planning postoperative therapy.

Radioimmunoguided surgery for recurrent colorectal cancer manifested by isolated CEA elevation.

BACKGROUND: Carcinoembryonic antigen (CEA) is a sensitive marker for detecting recurrent colorectal carcinoma. An asymptomatic rise of CEA can precede by several months the detection of recurrent cancer by standard imaging modalities. Yet, surgeons are hesitant to operate solely on the basis of an observed increase in CEA. We investigated the ability of radioimmunoguided surgery to enhance the surgeon's capability of detecting intraabdominal disease in these patients. METHODS: Nineteen patients who underwent radioimmunoguided surgery for suspected tumor recurrence based solely on elevated CEA were included in the study. They underwent colonoscopy and CT of the abdomen and chest, all of which were negative. They then underwent scintigraphy scan with an anti-CEA monoclonal antibody (MoAb) labeled with (99m)Tc or Indium I-111. All patients were injected with the CC49 MoAb (an anti-TAG-72 tumor-associated glycoprotein) labeled with (125)I three weeks before surgery. During surgery, traditional exploration was followed by survey with a gamma-detecting probe. RESULTS: Traditional surgical exploration identified 26 recurrent tumors: 7 hepatic, 8 pelvic, 6 retroperitoneal, 3 colonic, 1 splenic, and 1 anastomotic. Radioimmunoguided surgical exploration confirmed all recurrent tumors and identified additional tumor sites in seven patients that resulted in changing the surgical plan. CEA scans correlated with intraabdominal findings in seven patients. Abdominal pathology did not correlate completely with the scans in three patients, and CEA scan results were undetermined in two patients. CONCLUSION: Patients with elevated CEA and no other findings should be operated upon without delay, and radioimmunoguided surgery should be used to enhance the surgeon's knowledge of the extent of disease.

Identification of lymph node metastases in recurrent colorectal cancer.

Lymph node metastases are an important prognostic prediction factor in patients with recurrent colorectal cancer, particularly those with liver metastasis. Fifty-six patients with recurrent colorectal cancer were operated by us using the RIGS (radioimmunoguided surgery) technology. Patients were injected with 1 mg monoclonal antibody (MoAb) CC49 labeled with 2 mCi 125I. In surgery, traditional exploration was followed by survey with a gamma-detecting probe. Sixty of 151 patients enrolled in the Neo2-14 Phase III study for recurrent colorectal cancer were diagnosed with liver metastases based on preoperative CT. In 17/56 patients (30%), RIGS identified at least one tumor site confirmed by pathology (H&E). This resulted in 16 major changes in surgical plan. RIGS performance varied between lymphatic and non-lymphatic tissue, with positive predictive value (PPV) of 100% and negative predictive value (NPV) of 94% for non-lymphoid tissue, compared to PPV of 46.5% and NPV of 100% for the lymphoid tissue. Thirty-five out of 60 patients were considered resectable after traditional evaluation. RIGS identified occult tumor in 10 of these patients (28.5%). 7/10 occult patients expired (70%), while only 7/25 of the non-occult patients expired (28%) (P = 0.046). In localizing patients, no RIGS activity in lymph nodes signifies no tumor, while H&E confirmation is needed for decisions based on RIGS activity in the lymph nodes. RIGS provides important staging information, identifying patients for whom surgery may be done with curative intent.