Is carcino-embryonic antigen useful in the follow-up management of patients with colorectal liver metastases?

BACKGROUND

The role of carcino-embryonic antigen (CEA) in monitoring early detection of recurrent or metastatic colorectal cancer, and its impact on resectability rate and patient survival remains controversial. Our objective was to determine any association between the preoperative level of CEA and prognosis, and the resectability and survival by method of diagnosis of colorectal hepatic metastases.

METHODS

We analyzed patients who underwent exploration for hepatic resection for metastatic colorectal cancer over a 15-year period. The patient population consisted of those patients who had undergone primary colon or rectal resection and were followed up with serial CEA levels and of patients who were followed up with physical examination, liver function tests (LFTs) or computed tomography (CT) of the abdomen and pelvis that led to the diagnosis of liver metastases. Also included in the study were patients who were diagnosed with liver metastases at the time of the primary colon or rectal resection and underwent planned hepatic resection at a later time.

RESULTS

Three hundred and one (301) patients who underwent a total of 345 planned hepatic resections for metastatic colorectal cancer between January 1978 and December 1993 were included in this analysis. The median preoperative CEA level was 24.8 ng/mL in the resected group, 53.0 ng/mL in the incomplete resection group, and 49.1 ng/mL in the nonresected group (P = 0.02). More of the patients who had a preoperative CEA < or =30 ng/mL were in the resected group, while those who had a preoperative CEA >30 ng/mL were likely to be in the nonresected group (P = 0.002). The median survival was 25 months for patients with a preoperative CEA level < or =30 ng/mL and 17 months for patients with a preoperative CEA >30 ng/mL (P = 0.0005). The resectability rate and the survival of patients by method of diagnosing liver metastases-rising CEA versus history and physical, elevated LFTs, CT scan versus diagnosis at the time of primary resection-was not significant (P = 0.06 and P = 0.19, respectively). Given the nonstandardized retrospective nature of the study cohort and relative small groups of patients, the power to detect small differences in survival by method of diagnosis is limited. In the complete resection group of patients with unilobar liver disease (5-year survival of 28.8%) there was no difference in survival between those patients who had normal preoperative CEA and those who had elevated preoperative CEA, and approximately 90% of them had an abnormal preoperative serum CEA level.

CONCLUSIONS

CEA is useful in the preoperative evaluation of patients with hepatic colorectal metastases for assessing prognosis and is complimentary to history and physical examination in the diagnosis of liver metastases. Patients with colorectal liver metastases and preoperative CEA < or =30 ng/mL are more likely to be resectable, and they have the longest survival.

Low-dose monoclonal antibody CC49 administered sequentially with granulocyte-macrophage colony-stimulating factor in patients with metastatic colorectal cancer

The clinical and immunologic effects of murine monoclonal antibody (mAb) CC49 administered at a low dose sequentially with granulocyte-macrophage colony-stimulating factor (GM-CSF) were examined. Fourteen patients with metastatic colorectal cancer received 1 mg of unconjugated CC49 on day 1; on day 15 they began 125 micrograms/m2 GM-CSF by subcutaneous injection daily for 14 days, followed by 7 days of rest. Another 14 days of GM-CSF were then administered, followed by 7 days of rest. This 56-day cycle was repeated in patients whose cancer did not progress. Therapy was well tolerated; adverse allergic reactions were not observed. Objective tumor responses were not observed. Increases in antiidiotypic (T2) and anti-antiidiotypic (T3) cellular responses were observed, as were increases in human antimouse antibody levels. In contrast, the expression of Fc receptors on CD14+ peripheral blood monocytes decreased. This pilot study demonstrates idiotypic cellular immunologic effects of antitumor murine mAb, even at the doses used for imaging, and supports the sequential administration of GM-CSF as an adjuvant to mAb-based immunogens.

Staging of colorectal cancer: biology vs. morphology

PURPOSE

An accurate determination of the extent or staging of a disease is critical, because it provides the basis for making therapeutic decisions. Staging is a collaborative effort by the surgeon and the pathologist. Radioimmunoguided surgery has been evaluated for its ability to help surgeons determine the extent of disease during surgery, when management decisions have the most impact on patient care. This study was done to compare radioimmunoguided surgery "biostaging" with traditional pathologic staging (TNM) as predictors of survival in patients undergoing curative resections for colorectal cancer.

METHODS

Ninety-seven patients with colorectal cancer were prospectively enrolled in radioimmunoguided surgery protocols. Evaluation of follow-up survival data was performed. All patients underwent exploratory laparotomy and radioimmunoguided surgery with resection of their primary colorectal tumor. Survival data were analyzed with the Kaplan-Meier method with log-rank comparisons.

RESULTS

Of 97 patients enrolled in the study, 59 were evaluable and completely resectable by radioimmunoguided surgery. Mean follow-up was 62 months, with a range of 34 to 89 months. By traditional staging 13 patients were pStage I, 18 patients were pStage II, and 28 patients were pStage III. By radioimmunoguided surgery biostaging, 24 patients were radioimmunoguided surgery-negative whereas 35 patients were radioimmunoguided surgery-positive. Survival rates by pathologic stage approached a significant difference, but did not, as of the conclusion of the study period, reach it (P = 0.12). Survival rates based on radioimmunoguided surgery status demonstrated a highly significant difference (P = 0.0002).

CONCLUSIONS

Radioimmunoguided surgery biostaging provides new information intraoperatively on cancer staging that has not been available before. This may lead to new strategies for therapy that can be individualized and optimized for each patient with cancer.

Intraoperative radioimmunodetection

The radioimmunoguided surgery (RIGS) system employs a monoclonal antibody (CC49), a radionuclide (Iodine-125), and a hand-held gamma-detecting probe (the Neoprobe model 1000). The prototype cancer studied has been colorectal cancer. The antibody identifies a type of mucin, the by-product of the adenocarcinoma cancer cell. The RIGS system localizes up to 90% of colorectal cancers and finds additional RIGS-positive tissues in >50% of the patients. More than 90% of the RIGS-positive visceral tumors are identified by routine hematoxylin-and-eosin (H&E) light microscopy, but the RIGS-positive lymph nodes are H&E occult tissues in >70% of the cases. Enhanced, more time-consuming methods have been developed to confirm hidden cancer cells in these lymph node tissues. Survival data confirm the importance of RIGS-positive tissues. RIGS-positive tissues remaining at the completion of the surgical procedure portend a much poorer outcome than if the patient is deemed RIGS-negative at the completion of the surgical procedure (i.e., all RIGS-positive tissue was removed at surgery).

125Iodine brachytherapy for colorectal adenocarcinoma recurrent in the pelvis and paraortics

PURPOSE

To evaluate the results of 125I brachytherapy in colorectal cancers recurrent in the pelvis and paraortics.

METHODS AND MATERIALS

From September 1989 to January 1997, 29 patients with colorectal adenocarcinoma recurrent in the pelvis or the paraortic nodes were treated intraoperatively with permanent 125iodine seed implantation at the James Cancer Center of The Ohio State University (OSU). All patients had undergone prior surgery; 72% had prior EBRT. The implanted residual tumor volume was microscopic in 38% and gross in 62%. The implanted area (median 25 cc) received a median minimal peripheral dose of 140 Gy to total decay. An omental pedicle was used to minimize irradiation of the bowel. Five patients received additional postimplant EBRT (20-50 Gy; median 30 Gy).

RESULTS

The 1-, 2-, and 4-year actuarial local-regional control rates were 38%, 17%, and 17%, respectively, with a median time to local failure of 11 months (95% CI 10-12 months). The first manifestation of disease progression in 52 % of the patients was local-regional. In addition, 22 patients (75%) developed distant metastases. The 1-, 2-, and 4-year actuarial overall survival rates were 70%, 35%, and 21%, (median = 18 months; 95% CI: 14-22 months). Overall survival was better for patients smaller volume implants (p = 0.007), with a lower total activity implanted (p = 0.0003), with a smaller number of implanted sites (p = 0.004), and with microscopic residual disease (p = 0.01). Patients receiving additional EBRT also had a better prognosis (p = 0.005). Local tumor progression was the cause of death in 34% of the patients who have died at the time of this report and 56% died of distant metastases. Of the patients, 13 (45%) experienced 15 toxic events, including 3 patients (10%) with enteric fistula. Neuropathy was not observed.

CONCLUSIONS

125I brachytherapy can be successfully used for salvage in patients with recurrent colorectal cancer. Patients with isolated, microscopic, or minimal gross residual disease requiring small-volume implants and those receiving additional EBRT have a better prognosis. Postimplant EBRT is now routinely added, even for previously irradiated patients, in an attempt to improve local control. Compared to IOERT and IOHDR, 125I brachytherapy is not associated with clinical neuropathy, probably due to the continuous low dose rate irradiation delivered by the 125I seeds.

Radioimmunoguided surgery for patients with liver metastases secondary to colorectal cancer

BACKGROUND

Hepatic resection for metastatic colorectal cancer offers a 5-year survival rate of 30%. Selection of patients who are most likely to benefit from excision is challenging. The judgment is made by radiographic techniques preoperatively and by sight and touch and the instinct of the surgeon intraoperatively. Confirmation that all tumor tissue has been excised relies on the appearance and texture of the tissue and is verified by routine histology. The authors' objective was to evaluate (1) the ability of radioimmunoguided surgery (RIGS) to improve the intraoperative detection of metastatic disease, and (2) any change in the operative plan originating from the information gained in patients with colorectal liver metastases.

METHODS

Charts and tumor registry data for patients who underwent planned liver resection for colorectal cancer using the RIGS method from January 1985 to December 1993 were reviewed. This group of patients was compared to a similar group that underwent traditional liver resection for metastatic colorectal cancer during the same period. Patients who had the RIGS procedure during the earlier part of the period (1985-1990), were injected with tumor-associated glycoprotein (TAG) antibody B72.3; those in the later period (1990-1993) were injected with the second-generation anti-TAG monoclonal antibody CC49. Both monoclonal antibodies were labeled with sodium iodide I 125. Both traditional and RIGS exploration were used to determine the extent of the malignant process and any change in operative plan.

RESULTS

Seventy-four cases of planned liver resection were performed with the RIGS method (group I), and 215 cases were performed with the traditional method (group II). Age and sex distribution were similar in both groups, as were morbidity and mortality, with an overall perioperative mortality of 1%. The distribution and number of metastatic lesions to the liver were the same, although group I included more cases with smaller metastatic lesions and more patients with anatomic resections. No extrahepatic tumor was found in 140 patients (65%) in group II, whereas there were only 21 patients (28%) in group I in whom no extrahepatic disease was detected (P < .001). RIGS exploration identified additional tumor in 12 (16%) of 74 cases: in the gastrohepatic ligament lymph nodes (LN) in five patients, in the celiac axis LN in one patient, and in the periaortic LN in six patients. These discoveries changed the operative plan for all of these patients, avoiding excision in the latter six patients and extending the resection in the other six.

CONCLUSIONS

RIGS surgery provides an immediate and more accurate intraoperative staging system of patients with colorectal liver metastases than does traditional exploration by identifying additional metastatic disease, mainly to the lymph nodes, thus changing the plan of resection in a significant number of patients. More studies are needed to evaluate any significant survival advantage of patients who undergo removal of all RIGS-positive tissue.

First results for resetting the antitumor immune response by immune corrective surgery in colon cancer

BACKGROUND

A critical step for cancer recurrence is the failure of the cellular immune response. It is suspected that chronic humoral immune responses against some tumor-associated antigens (TAA) can contribute to that failure.

METHODS

In this study, we tested the ability of an immune corrective surgical procedure to prevent recurrences of colon cancer in stages I, II, and III. Radiolabeled anti-TAG antibodies injected intravenously become concentrated on TAG-72 immune complexes presented by follicular dendritic cells, which are responsible for the persistent humoral response against TAG-72 TAA. Using a hand-held gamma probe, we can intraoperatively detect and remove lymph nodes involved in TAG-72 presentation. By removing these lymph nodes, together with the tumor tissue, presentation and source of TAG-72 are drastically reduced.

RESULTS

The impact of this TAA suppression on the tumor recurrence process is analyzed in a sample of 24 patients. The immune corrective surgical procedure did not increase morbidity. Five years after surgery the following were disease free: 5 of 5 stage I, 6 of 6 stage II, and 10 of 13 stage III. The global survival of this group was 87.5%. Compared with the standard surgical treatment of colon cancer (58% survival for the same stages), this surgical immune corrective procedure introduces a statistically significant improvement of 29% (P <0.001).

CONCLUSIONS

The surgical removal of lymph nodes involved in the persistent humoral immune response against TAA has an important beneficial impact on colon cancer treatment.

[Lymphadenectomy in colorectal carcinoma]

Recurrence of colorectal carcinomas occurs in about 50% of the cases with localized neoplasia. It is understood that the tumor recurrence is due to residual micrometastases not found during surgery or extraregional (peripheral blood or bone marrow). We developed a procedure to detect non-visible, abdominal metastases using a radiolabeled anti-tumor cell antibody injected before the operation (radioimmunoguided surgery RIGS). However, even with the best technique, it is not possible to remove all micrometastasis if a hematogenic dissemination happens. Based on the knowledge of disturbing humoral immune reaction is mounted against shed tumor associated antigens (TAA), we developed a new method to reduce and correct the B cell response and B cell recruitment due to chronic TAA immun complex presentation on follicular dendritic cells (immune corrective surgery, ICS). This method is based on a selective lymphadenectomy. The target lymph nodes were those loaded with TAA-immune complex. The detection method used was the injection of radiolabeled antibody able to recognize the immune complex. From 20 patients (stage I, II and III) treated with ICS, 17 survived more than 5 years 'showing a statistically significant increase of survival compared to patients treated with standard procedures. In conclusion, these data show that surgery of colorectal cancer should be selectively extended to specific anatomical regions in order to remove hidden micrometastases, and more importantly, correct postoperative immune processes that could suppress the T cell response against residual tumor cells.

Determinants of survival following hepatic resection for metastatic colorectal cancer

Hepatic resection remains the only potentially curative treatment for metastatic colorectal cancer. This retrospective review study was undertaken in an attempt to identify factors that influence patient survival following hepatic resection for metastatic colorectal cancer. From January 1978 to December 1993, a total of 301 patients underwent a total of 345 planned hepatic resections for metastatic colorectal cancer. Of those, 245 patients had one resection, 44 had two resections, and 12 had three resections. For all patients the overall median survival was 20.6 months, operative mortality was 1.1%, and overall morbidity was 17.2%. Average hospital stay was 9 days. Statistical analysis included univariate analysis using log rank comparisons, Kaplan-Meier survival curves, and multivariate analysis using Cox proportional hazards regression. The statistically significant factors that influenced survival were distribution of liver metastases, unilobar versus bilobar (p = 0.0001), resected versus nonresected (p < 0.0001), and tumor-free surgical margins versus positive margins (p = 0.001). Surprisingly, the disease-free interval and the original stage of the primary tumor did not predict survival (p = not significant). Other factors that had no influence on survival were type of resection, size and number of liver metastases, ABO blood group, and the number of perioperative blood transfusions. For those patients who underwent resection of unilobar metastases with tumor-free margins, the 5-year survival rate was 29% with a median survival of 35 months and eight survivors > 7 years. In addition, one patient with bilobar disease had survival > 7 years and five patients who had resection of hepatic metastases and extrahepatic cancer simultaneously had survival > 3 years. Our data support the concept that patients with unilobar metastatic disease who undergo surgical resection with tumor-free surgical margins can be afforded a significant opportunity at long-term survival with acceptable morbidity, mortality, and hospital stay. Also, certain patients with bilobar or extrahepatic disease (or both) who undergo complete resection can enjoy a long-term survival. In these subgroups of patients resection should be considered on an individual basis.

Radioimmunoguided Surgery for Gastrointestinal Malignancies: An Analysis of 14 Years of Clinical Experience

BACKGROUND: The identification of all sites of intra-abdominal adenocarcinoma is key to optimal surgical resection and tumor staging. Conventional imaging methods and direct visualization and palpation have limited sensitivity and specificity. Radioimmunoguided surgery (RIGS) has a potential to improve these parameters. METHODS: The development of the RIGS concept is presented, and the studies of tumor localization, detection of disseminated disease, staging, and survival are correlated with the tumor biopsy of gastrointestinal carcinoma, particularly colorectal carcinoma. RESULTS: RIGS can detect clinically and histologically occult neoplasm. Also, by providing immediate intraoperative information, the RIGS approach improves surgical staging, impacts on surgical and medical care, and affects patient prognosis. CONCLUSIONS: RIGS may become the standard of care for the surgical staging and treatment of colorectal cancer and other gastrointestinal malignancies.

Assessment of disseminated pancreatic cancer: a comparison of traditional exploratory laparotomy and radioimmunoguided surgery

BACKGROUND

After curative resection for pancreatic cancer, only 10% of patients survive disease for 5 years. These dismal results suggest the presence of occult tumor at the time of initial operation. This phase I/II study was conducted to compare traditional exploratory laparotomy with radioimmunoguided surgery (RIGS) in the assessment of disseminated pancreatic cancer.

METHODS

Ten patients with the diagnosis of adenocarcinoma of the pancreas were injected intravenously with 1 mg CC49 monoclonal antibody radiolabeled with 2 mCi iodine 125. All patients were evaluated by a standard abdominal exploration followed by RIGS. Tumor identified by each technique was documented and categorized as neoplasm disseminated to viscera or lymphatics.

RESULTS

There were 25 visceral sites of disease that were traditionally discovered at the time of exploration including pancreas, omentum, small bowel, pelvis, liver, and other. All 25 sites of disease were positive by RIGS plus an additional four sites of visceral tumor for a total of 29 RIGS positive sites of disease. Six lymphatic sites of disease were discovered by traditional examination; however, 44 sites of lymphatic sites were documented by RIGS (p < 0.001). In addition, nine traditionally and pathologically negative/RIGS positive nodes were subjected to cytokeratin and MOC 31 immunohistochemistry. Six of nine nodes were positive by cytokeratin immunohistochemistry, and five of the six cytokeratin positive nodes were MOC 31 positive.

CONCLUSIONS

These data suggest that the RIGS technique detected significantly more foci of visceral spread of tumor than traditional exploratory laparotomy and significantly more sites of lymphatic dissemination were identified by RIGS than by standard exploration.

Oncogene and cytokine expression of human colorectal tumors responding to immunotherapy

Tumor samples from five patients with metastatic colorectal cancer who demonstrated tumor regressions in clinical trials of interleukin (IL)-1 beta, IL-2, and adoptive cellular therapy were analyzed for oncogene and cytokine mRNA expression. Tumors from eight nonresponding patients were also studied. Mutations of the ras protooncogene and overexpression of c-myc protooncogene were observed in both responding and nonresponding tumors. In contrast, none of the responding tumors expressed transforming growth factor (TGF)-beta 1 mRNA, whereas nonresponding tumors did. The expression of IL-1, IL-6, IL-8, IL-10, tumor necrosis factor-alpha, granulocyte macrophage-colony-stimulating factor, macrophage inflammatory protein (MIP)-1 alpha, MIP-1 beta, macrophage chemotactic protein, and RANTES was variable between responding and nonresponding patients. Although we cannot conclude that a pattern of oncogene and/or cytokine mRNA expression specifically characterizes sensitive colorectal cancers, these analyses-the assessment of TGF-beta 1 mRNA in particular-merit further evaluation as biomarkers prognostic of immunotherapy response.

Clinical and immunologic effects of monoclonal antibody CC49 and interleukin-2 in patients with metastatic colorectal cancer

We examined the possibility that prior exposure to the murine monoclonal antibody (mAb), CC49, which recognizes the pancarcinoma antigen, TAG-72, would modify the clinical activity of interleukin-2 (IL-2) in patients with metastatic colorectal cancer. Fourteen patients received 2 mg of unconjugated CC49 on Day 1; on Day 22, they began human recombinant IL-2 at 1 mg/m2/day for 4 days by continuous IV infusion. Four-day cycles of IL-2 were repeated weekly for 8 weeks unless there was evidence of unacceptable toxicity or progressive disease. Therapy was well tolerated. Proliferative responses of peripheral blood mononuclear cells (PBMC) to CC49, its Fab fragment, isotype matched murine immunoglobulin, and CC49 complexed with TAG-72+ mucin increased after CC49 administration (Day 21). These proliferative responses decreased after IL-2 administration. PBMC proliferative responses to AI49, an anti-CC49 idiotype antibody (Ab2), and TAG-72+ mucin was not induced. No complete or partial clinical responses were observed; one patient manifested a transient mixed response. A single infusion of CC49 does have biologic activity; it is, however, unlikely to substantially modify tumor response rates effected by IL-2 in patients with metastatic colorectal cancer.

Pharmacokinetics of iodine-125 CC49 monoclonal antibody in patients with colon cancer

Radioimmunoguided Surgery techniques which use radiolabeled tumor specific markers and an intraoperative detector in an attempt to improve therapy and survival in patients with cancer have been under development for over fifteen years. Monoclonal antibody (MAb) CC49 is a second-generation murine IgG1 which has improved localization properties over its predecessor, MAb B72.3, and has been studied in a number of patients. In order to determine the pharmacokinetics of iodine-125 (125I) CC49 MAb, size-exclusion, high-performance liquid chromatography (HPLC) was used to assess radioactive components in serum and urine following administration of the drug to colon cancer patients.

METHODS

Five patients received an intravenous infusion of 10 mg of MAb CC49 labeled with 2 mCi 125I. Following infusion, serum and urine specimens were collected from patients at predetermined time intervals prior to surgery. HPLC analysis of these specimens was completed to determine the radioactive species in each sample.

RESULTS

Serum and urine specimens showed that serum levels of CC49 decrease exponentially and become unmeasurable by day 14 (half-life 1.89 days, +/- 0.19), with a steady, low-level of free 125I measurable in postinjection serum until day 21 after infusion. There was no evidence of MAb fragmentation or antibody:antigen (Ab:Ag) complex formation in serum, and no evidence of whole MAb, F(ab')2, or Fab fragment excretion in urine. Preinjection sera with MAb added in vitro also failed to demonstrate Ab:Ag complex formation. Analysis of urine showed low level excretion of free 125I which peaked by day 1 and declined exponentially through day 21, with a very low molecular weight (< 1 kDa) MAb fragment excreted in urine between 1 and 21 days.

CONCLUSION

Radioiodinated 125I CC49 MAb remains in serum of cancer patients approximately 14 days, and tissue radioactivity beyond this time may reflect tissue sequestered MAb and/or free 125I and not "bloo pool" radioactivity. CC49 MAb appears to be deiodinated in small but significant quantities before it is metabolized, and clearance of radioactivity is mainly in free 125I form in urine. Measurable quantities of a < 1 Kda MAb fragment in urine and not serum may suggest a renal mechanism of MAb metabolism, but may also represent a metabolic end product of MAb metabolism with a very short serum half-life (T1/2) which accumulates in urine.

Intra-abdominal patterns of disease dissemination in colorectal cancer identified using radioimmunoguided surgery

PURPOSE

Patterns of metastatic spread are difficult to determine with routine postoperative follow-up. This study was undertaken to evaluate two selected populations of colorectal cancer patients injected and screened with anti-tumor antibody.

METHODS

Eighty-six evaluable patients with colorectal cancer underwent exploratory laparotomy with both traditional surgical exploration and radioimmunoguided surgery (RIGS) following injection of 125I-labeled CC49 monoclonal antibody. RIGS-positive tissue detectable with a handheld gamma-detecting probe was defined as tissue involved with the disease process. Comparisons were made between extent of disease using traditional exploration and extent using RIGS.

RESULTS

In 41 patients with primary disease, traditional exploration detected 45 sites of disease (1.1 sites/patient) compared with 153 RIGS-positive sites (3.7 sites/patient). In 45 patients with recurrent disease, traditional exploration found 116 sites (2.6 sites/patient) vs. 184 RIGS-positive sites (4.1 sites/patient). Involvement by selected anatomic sites is shown below [Table: see text].

CONCLUSION

RIGS detected more tissue involved in disease process for all sites in both primary and recurrent disease except liver metastases. Areas with highest proportion of RIGS-positive tissue, the gastrohepatic ligament and celiac nodes, are rarely resected and are not pathologically examined. Positive RIGS localization of tumor antigen in these areas suggests more extensive dissemination of disease process.

Radioimmunoguided surgery for colorectal cancer

BACKGROUND

Operations for patients with colorectal cancer are based on traditions established by historical experience. Radioimmunoguided surgery (RIGS) provides new information that challenges these traditions.

METHODS

Thirty-two patients with primary colorectal cancer underwent RIGS after being injected with anti-TAG-72 murine monoclonal antibody CC49 labeled with iodine-125. Sixteen of the patients had all gross tumor and RIGS-positive tissue removed (RIGS-negative group), and 16 had only traditional extirpation of the tumor because RIGS-positive tissue was too diffuse (RIGS-positive group).

RESULTS

In the 16 patients having all RIGS-positive tissue removed, five had traditional regional en bloc resections and 11 had additional extraregional tissues resected. Identification of extraregional disease added two liver resections and 25 lymphadenectomies: 10 of the gastrohepatic ligament, five celia axis, six retroperitoneal, and four iliac. With a median follow-up of 37 months, survival in the RIGS-negative group is 100%. In 14 of 16 patients (87.5%) there is no evidence of disease. In the RIGS-positive group, follow-up shows 14 of 16 patients are dead and two are alive with disease (p < 0.0001).

CONCLUSION

These results suggest that RIGS identifies patterns of disease dissemination different from those identified by traditional staging techniques. Removal of additional RIGS-positive tissues in nontraditional areas may improve survival.

Intraoperative detection of occult colon cancer micrometastases using 125 I-radiolabled monoclonal antibody CC49

BACKGROUND

The detection of locally-disseminated disease is one of the principal goals of oncologic surgery. For this study, a hand-held, gamma-detecting probe was used intraoperatively to assess the extent of colorectal carcinoma in patients previously injected with radiolabeled antibody to the TAG-72 antigen (CC49); this technique is known as Radioimmunoguided Surgery (RIGS) (Neoprobe Corporation, Dublin, OH). RIGS-positive areas (i.e. those with increased signal over background) have previously been shown to contain carcinoma in a high proportion of cases. However, some RIGS-positive areas had no tumor detectable by clinical examination or routine histopathologic analysis. This study was undertaken to determine if the presence of occult metastases might account for this disparity.

METHODS

A total of 57 regional lymph nodes (LN), resected from 16 patients with primary (9) or recurrent (7) colorectal carcinoma, were studied. The patients were injected with 125I labeled CC49 murine monoclonal antibody approximately 3 weeks prior to surgery. After routine histologic evaluation, the LN were analyzed for occult metastases; paraffin sections were cut at 5 levels (50 micron apart) and were examined by histology (hematoxylin and eosin stain [H & E]) and by immunohistochemistry (IHC) with a cocktail of monoclonal antibodies to cytokeratins.

RESULTS

Fifty-seven LN were included in this study; 17 were H & E-positive (i.e., contained tumor by routine histologic examination [overt tumor]), while 40 LN were H & E-negative (i.e., no evidence of tumor after routine histologic examination). Thirty-nine LN were RIGS-positive, but only 14 of these were H & E-positive. Of the 25 RIGS-positive/H & E-negative LN, 10 (40%) demonstrated the presence of occult metastases after serial section/IHC analysis. Thus, a total of 27 LN contained metastatic carcinoma (17 overt, 10 occult); routine histologic analysis was able to identify tumor in only 17 of these 27 LN (63%), while the probe signaled the presence of tumor in 24 of these LN (89%). None of the RIGS-negative/H & E-negative LN were found to have occult metastases (0/15). Specific immunoreactivity with CC49 antibody was observed in 5 of 15 RIGS-positive/H & E-negative LN in which no tumor could be identified by any method (histopathology or IHC. CC49 immunoreactivity was not observed in 15 RIGS-negative/H & E-negative LN.

CONCLUSIONS

The finding of a RIGS-positive LN had a significant association with the presence of tumor cells (P < 0.05). In this study, the RIGS procedure was more sensitive than clinical or histopathologic examination in detecting the regional spread of a tumor. Furthermore, in LN that showed no evidence of tumor by routine histopathologic examination, a positive RIGS reading was significantly associated with the presence of occult LN metastases (P < 0.01). This study is the first to demonstrate the detection of histologically occult tumor by a remote imaging device. RIGS assessment is a highly sensitive method for detecting occult tumor deposits, and may guide therapeutic intervention in patients with colorectal carcinoma.

Intraperitoneal hyperthermic perfusion with mitomycin C for colorectal cancer with peritoneal metastases

BACKGROUND

Intraperitoneal (i.p.) metastases pose a special problem for surgical treatment because of their multiplicity and microscopic size. This study was designed to examine the feasibility and safety of i.p. hyperthermic perfusion (IPHP) with mitomycin C (MMC) for treating recurrent colorectal cancer.

METHODS

Fifteen patients with metastatic colon cancer were treated. All patients underwent cytoreductive procedures leaving only residual i.p. metastases < 1 cm in diameter. All patients had received prior systemic chemotherapy, but their disease had progressed. Intraperitoneal chemotherapy was administered through three large catheters (28 French) using a closed system of two pumps, a heat exchanger, and two filters. After the patient's abdominal temperature reached 41 degrees C, 45-60 mg of MMC was circulated intraperitoneally for 1 h.

RESULTS

The majority of patients had various anastomoses: small bowel (n = 11), large bowel (n = 5), and urologic (n = 5). No anastomotic complications occurred in any of the patients. One patient experienced severe systemic MMC toxicity, which caused cytopenia and respiratory depression. In all patients the carcinoembryonic antigen (CEA) level decreased after surgery and IPHP. Median follow-up was 10 months, and recurrence was defined as an elevation in CEA level. Disease recurred in three patients within 5 months, and disease recurred in seven other patients over the next 3 months; one patient remains clinically free of disease after 8 months.

CONCLUSION

Our data suggest that IPHP is a safe palliative method of treatment for patients with peritoneal carcinomatosis. The median patient response duration of 6 months may warrant consideration of a repeat IPHP procedure at that time.

Surgical applications of gamma-detecting probes

The RIGS system is a technology which was developed to provide a more sensitive and accurate method of detecting colorectal cancer during surgery. One of the components of this system is the hand-held, gamma-detecting probe [Neoprobe Model 1000instrument; Neoprobe Corporation, Dublin, Ohio), used by the surgeon to identify preadministered, radiolabeled monoclonal antibody which has localized to dis- eased tissue. RIGSuses sound-directed gamma detection to identify and locate cancer which may not be seen or felt by the surgeon. The success of RIGS has been largely due to the remarkable sensitivity of the gamma- detecting probe in detecting small amounts oflow-energy radioactivity. This attribute has led to the use of the probe for other surgical applications including pre- and intraoperative lymphatic mapping, and parathyroid localization. Surgery for melanoma, breast cancer, parathyroid disease, and colorectal cancer has been af- fected by the increased use of the gamma-detecting probe both in clinical trials and practice. This chapter will review the many applications of this new technology.

Peritoneal carcinomatosis and radioimmunoguided surgery

The Radioimmunoguided Surgery (RIGS) system was developed, in part, to detect occult tumor in patients with recurrent colorectal cancer. Unfortunately, however, patients are sometimes found to have unresectable peritoneal metastasis. For these patients, intraperitoneal hyperthermic perfusion (IPHP) with mitomycin C (MMC) was used as a novel treatment method. Thirty-six intraperitoneal hyperthermic perfusions with MMC were given over the course of several studies. A preliminary study delineated two groups as possible candidates for this treatment: patients with pseudomyxoma peritonei and patients with peritoneal metastasis < 0.5 cm. Intraperitoneal hyperthermic perfusion (IPHP) was conducted for 1 hour after achieving an abdominal temperature of 41 degrees C. A dose of 30 mg MMC in 31 Plasmalyte was injected followed by a second 30 mg dose given at 30 minutes. Plasma pharmacokinetics of IPHP with MMC indicate an advantage in the range of 100-fold enhancement of exposure compared with delivery in plasma. The method was found to be safe when flow was observed and dosage decisions were made during perfusion according to flow. A clinical study group consisting of 15 patients underwent cytoreductive surgery followed by IPHP. The majority of them had either gastrointestinal or urologic anastomoses. There were no complications. In every patient the CEA level decreased after surgery and IPHP, with a median response of 6 months. RIGS technology aided in the selection of IPHP as a treatment choice by demonstrating the presence of an occult tumor burden in those patients whose traditional explorations were deceiving. This chapter includes technical details and suggestions for improving and modifying the use of IPHP.

The legislative and litigation history of special education

Between the mid 1960s and 1975, state legislatures, the federal courts, and the U.S. Congress spelled out strong educational rights for children with disabilities. Forty-five state legislatures passed laws mandating, encouraging, and/or funding special education programs. Federal courts, interpreting the equal protection and due process guarantees of the Fourteenth Amendment to the U.S. Constitution, ruled that schools could not discriminate on the basis of disability and that parents had due process rights related to their children's schooling. Congress, in legislation now retitled the Individuals with Disabilities Education Act (IDEA), laid out detailed procedural protections regarding eligibility for special educational services, parental rights, individualized education programs (IEPs), the requirement that children be served in the least restrictive environment, and the need to provide related (noneducational) services. Decisions on instructional matters such as curricula and the elements of the IEP remain the province of local and state authorities. Advocates for students with disabilities have continually sought separate (categorical) funding for special education services. Current movements toward block grants rather than categorical programs and toward greater inclusion of special education students in general education classrooms raise concerns in some quarters about whether students with disabilities will continue to have full access to the special services they need. While the cost of special services may be an unexpressed criterion in many decisions made by school districts, nowhere does the IDEA explicitly allow cost to be considered. Where a service is necessary for an individual child, cost considerations would not allow a school district to escape its obligations to the child. However, in instances where more than one appropriate configuration of services is available to meet a child's needs, the school district may be allowed to consider the cost of different alternatives.