Labile assembly of a tardigrade protein induces biostasis

Tardigrades are microscopic animals that survive desiccation by inducing biostasis. To survive drying tardigrades rely on intrinsically disordered CAHS proteins, which also function to prevent perturbations induced by drying in vitro and in heterologous systems. CAHS proteins have been shown to form gels both in vitro and in vivo, which has been speculated to be linked to their protective capacity. However, the sequence features and mechanisms underlying gel formation and the necessity of gelation for protection have not been demonstrated. Here we report a mechanism of fibrillization and gelation for CAHS D similar to that of intermediate filament assembly. We show that in vitro, gelation restricts molecular motion, immobilizing and protecting labile material from the harmful effects of drying. In vivo, we observe that CAHS D forms fibrillar networks during osmotic stress. Fibrillar networking of CAHS D improves survival of osmotically shocked cells. We observe two emergent properties associated with fibrillization; (i) prevention of cell volume change and (ii) reduction of metabolic activity during osmotic shock. We find that there is no significant correlation between maintenance of cell volume and survival, while there is a significant correlation between reduced metabolism and survival. Importantly, CAHS D's fibrillar network formation is reversible and metabolic rates return to control levels after CAHS fibers are resolved. This work provides insights into how tardigrades induce reversible biostasis through the self-assembly of labile CAHS gels.

Ex vivo electrical impedance measurements on excised hepatic tissue from human patients with metastatic colorectal cancer

Point-wise ex vivo electrical impedance spectroscopy measurements were conducted on excised hepatic tissue from human patients with metastatic colorectal cancer using a linear four-electrode impedance probe. This study of 132 measurements from 10 colorectal cancer patients, the largest to date, reports that the equivalent electrical conductivity for tumor tissue is significantly higher than normal tissue (p < 0.01), ranging from 2-5 times greater over the measured frequency range of 100 Hz-1 MHz. Difference in tissue electrical permittivity is also found to be statistically significant across most frequencies. Furthermore, the complex impedance is also reported for both normal and tumor tissue. Consistent with trends for tissue electrical conductivity, normal tissue has a significantly higher impedance than tumor tissue (p < 0.01), as well as a higher net capacitive phase shift (33° for normal liver tissue in contrast to 10° for tumor tissue).

Origins of electronic band gap reduction in Cr/N codoped TiO2

Recent studies indicated that noncompensated cation-anion codoping of wide-band-gap oxide semiconductors such as anatase TiO2 significantly reduces the optical band gap and thus strongly enhances the absorption of visible light [W. Zhu et al., Phys. Rev. Lett. 103, 226401 (2009)]. We used soft x-ray spectroscopy to fully determine the location and nature of the impurity levels responsible for the extraordinarily large (∼1 eV) band gap reduction of noncompensated codoped rutile TiO2. It is shown that Cr/N codoping strongly enhances the substitutional N content, compared to single element doping. The band gap reduction is due to the formation of Cr 3d3 levels in the lower half of the gap while the conduction band minimum is comprised of localized Cr 3d and delocalized N 2p states. Band gap reduction and carrier delocalization are critical elements for efficient light-to-current conversion in oxide semiconductors. These findings thus raise the prospect of using codoped oxide semiconductors with specifically engineered electronic properties in a variety of photovoltaic and photocatalytic applications.

Single-institution experience comparing double-barreled wet colostomy to ileal conduit for urinary and fecal diversion

542

Background: Patients with advanced primary or recurrent colorectal cancers that undergo total pelvic exenteration for cure or palliation require proximal urinary and fecal diversion. The most commonly used diversion technique is use of an ileal conduit (IC) and end colostomy. At our institute, the double-barreled wet colostomy (DBWC) has been shown to be have similar outcomes and technically feasible.

Methods: Between 2004 and 2010, 37 patients underwent total pelvic exenteration for advanced primary or recurrent colorectal cancer. Two groups were identified based on the technique used for their urinary diversion, either by way of an IC (n = 4) or DBWC (n = 33). Demographics, periprocedural events, and outcomes were compared between the two groups.

Results: The two groups were similar in the terms of age, gender, and comorbidities. Thirty-three patients (89%) underwent a DBWC and four patients (11%) underwent an IC. All of these patients underwent a total pelvic exenteration for advanced primary (27%) or recurrent colorectal cancer (73%) either for cure or for palliation. Twenty patients underwent R0 resection (54%), and 17 patients had non-R0 resection (46%). Complications, length of stay, and operative times between both groups were similar. Median survival for both groups showed no statistical difference.

Conclusions: DBWC is a safe and feasible alternative to the traditional ileal conduit for urinary diversion. It provides a single stoma to care for, and an intact contralateral abdominal muscle to use as a vertical rectus abdominus musculocutaneous flap for reconstruction. This technique is easy to learn and is not associated with higher operative times, length of stay, morbidity, or mortality.

[Table: see text]

No significant financial relationships to disclose.

Pelvic malignancies undergoing exenteration

579

Background: Pelvic exenteration is reserved for patients with locally invasive and recurrent pelvic malignancies. The literature demonstrates a high morbidity and mortality associated with this operation. At our institution, a high volume of pelvic exenterations are undertaken and their outcomes have been studied.

Methods: The medical records of 53 patients with varying pelvic pathologies who underwent pelvic exenteration between 2004 and 2010 were reviewed. Demographics, histologies, periprocedural events, and outcomes were analyzed.

Results: Patients were divided into a colorectal (n = 37) and noncolorectal (n = 16) group for analysis based on histology. The two groups were similar in demographics, perioperative events, and length of stay. Resection status, chemotherapy use, and intraoperative radiation therapy showed no statistical difference. Complications showed a difference in perineal abscesses in the colorectal group. The colorectal group showed a survival difference when comparing R0 resection versus R1/R2, however no difference was seen in primary versus recurrent tumors. The median survival was 20.3 months in the colorectal group and 4.8 months in the noncolorectal group.

Conclusions: Patients undergoing exenteration for colorectal histology have improved survival when compared to pelvic malignancies of other origins. The greatest effect on long term survival is seen in the colorectal group undergoing a R0 resection. Despite pelvic exenterations carrying a high morbidity and mortality, careful patient selection can optimize outcomes.

[Table: see text]

No significant financial relationships to disclose.

Y-90 radioembolization in the treatment of colorectal cancer that is metastatic to the liver

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Background: Y-90 radioembolization has shown promise in the treatment of unresectable metastatic colorectal cancer (mCRC) and primary hepatocellular carcinoma (HCC). The goal of our study was to assess the efficacy in patients with refractory mCRC who underwent Y-90 radioembolization.

Methods: Patients with unresectable mCRC to the liver underwent treatment at the Ohio State University with resin microspheres. Response to treatment or progression of disease was assessed by CT imaging per RECIST criteria. Overall survival (OS) and progression free survival (PFS) were estimated by Kaplan-Meier method. Log-rank test was used to compare the survival curves between the groups. The Cox-regression model was used to explore any association between time to treatment and PFS (or OS).

Results: 24 patients with a mean age of 63 years old were included. 54% of patients had extrahepatic disease, 67% had hepatic bilobar involvement, and more than 80% of our patients had more than two chemotherapy regimens prior to initiation of Y-90 radioembolization. There were no objective responses radiographically. 5 patients had a CEA response. The estimated median PFS and OS were 3.9 months (CI 95%: 2.4,4.8) and 8.9 months (CI 95%: 4.2,16.7), respectively. Patients with any CEA response to treatment tended to have a significantly longer PFS (4.8 months vs. 2.7 months, p=0.088), but no significant association with OS (p=0.64). The presence of extrahepatic disease prior to initiation of treatment resulted in a significantly lower PFS (2.9 vs. 5.1 months, p=0.076) but no significant difference in OS (p=0.86). Patients older than 65 appeared to have an improvement in PFS compared to younger patients (4.6 vs. 2.4 months, p=0.052). There was no significant association between the time to initiation of treatment and PFS (p=0.63) or OS (p=1).

Conclusions: Y-90 radioembolization appears to have promising activity in patients with refractory unresectable liver metastasis from mCRC. Factors such as older age and absence of extrahepatic disease may be associated with improved outcomes. CEA response may be a surrogate marker for benefit. Large randomized studies need to confirm our findings.

No significant financial relationships to disclose.

Age-related hypermethylation of the 5' region of MLH1 in normal colonic mucosa is associated with microsatellite-unstable colorectal cancer development

Hypermethylation of the MLH1 promoter underlies most sporadic colorectal cancers with microsatellite instability (MSI). To investigate the role of hypermethylation in the normal colonic mucosa as a possible precursor lesion, we studied 700 bp upstream of MLH1 covering 51 CpG sites. We found partially methylated alleles in 15 of 34 (44%) patients <60 years of age and 20 of 24 (83%) patients > or =80 years of age (P = 0.0026). Fully methylated alleles were present in 18 of 33 (55%) patients with MSI+ tumors but in only 18 of 90 (20%) patients with MSI- tumors (P = 0.00019). By in situ analysis, methylation was patchy and located mainly in the cryptal regions close to the lumen. We conclude that the spread of methylation in the MLH1 promoter in the normal colonic mucosa is closely associated with age and the development of sporadic MSI+ colorectal cancers.

Fluorodeoxyglucose positron emission tomography as an adjunct to carcinoembryonic antigen in the management of patients with presumed recurrent colorectal cancer and nondiagnostic radiologic workup

BACKGROUND

The purpose of this study was to determine the role of fluorodeoxyglucose positron emission tomography (PET) in localizing disease in patients with colorectal cancer with radiologically occult symptomatology or increases in carcinoembryonic antigen (CEA) level.

METHODS

Two hundred seventy-seven patients with colorectal cancer underwent PET scanning between November 1998 and September 2000 prompted by (1) increasing CEA level and nondiagnostic imaging or (2) symptoms with normal CEA level and nondiagnostic imaging. PET results were correlated with operative findings/histology, clinical follow-up data, and CEA level to determine PET's accuracy in determining the source of symptoms or CEA.

RESULTS

Fifteen patients had increasing CEA levels, and 14 had abnormal PET. Two of these 14 were denied exploration because PET suggested widely metastatic disease. Nine patients underwent exploration with curative intent. In 1 patient, recurrence was not pathologically confirmed (false-positive rate, 8%). Two had disease beyond that predicted by PET, and 6 underwent complete resection and normalized their CEA levels. Four symptomatic patients with normal CEA levels and negative x-rays had abnormal PET; at exploration, 3 had no evidence of recurrence.

CONCLUSIONS

PET imaging can often accurately localize the source of radiologically occult increases in CEA level and select that subset of patients eligible for therapeutic laparotomy. Symptomatic, PET-positive patients with normal CEA levels frequently undergo nontherapeutic laparotomy, and PET findings should be interpreted with caution in these patients.

18F-labeled fluorodeoxyglucose positron emission tomography-guided surgery for recurrent colorectal cancer: a feasibility study

OBJECTIVE

Positron emission tomography (PET) scanning is an accepted diagnostic tool for the detection of colorectal cancer (CRC). The purpose of this study was to determine whether diagnostic information offered by preoperative PET scan could be used to detect disease intraoperatively using beta and gamma handheld probes.

METHODS

Two studies were carried out. First, tumor "phantoms" were created using 62 microCi fluorodeoxyglucose (FDG) in a saline-filled basin. Gamma and beta handheld probes were used to determine detection characteristics with respect to probe type, distance from source, and isotope half-life. In a second study, probes were used intraoperatively to detect tumor in 10 patients with recurrent colorectal cancer as determined by preoperative PET scan. Counts relative to background were determined for each probe as was histopathologic correlation with probe-positive tissue.

RESULTS

Phantom studies documented that FDG detection by each probe was nonlinearly related to source proximity and half-life. In human subjects, abnormal findings on preoperative PET studies were detected by both probes with tumor:normal ratios of 1.6 (beta) and 1.5 (gamma). All probe-positive tissue was histologically confirmed to be recurrent colorectal cancer.

CONCLUSIONS

Intraoperative detection of CRC using an FDG source and beta and gamma probes correlates with preoperative PET. With further improvements in probe technology, successful differentiation of normal and tumor tissue as shown here may allow for more precise localization and directed resection.

Serum pancreastatin levels predict response to hepatic artery chemoembolization and somatostatin analogue therapy in metastatic neuroendocrine tumors

INTRODUCTION

Neuroendocrine tumors often metastasize to the liver and present with disabling hormonal symptoms. Hepatic artery chemoembolization (HACE) combined with somatostatin therapy, pre-embolization, peri-embolization and post-embolization, at doses to control symptoms, is an aggressive approach that can relieve hormonal symptoms with minimal morbidity and mortality.

METHODS

Chemoembolization was performed using 30 mg of adriamycin, 50 mg of mitomycin, 12 ml of hexabrix, 10 ml of ethiodol, and 360-500-microm particles. Pancreastatin, a split product of chromogranin A, was measured pre-HACE and post-HACE in all patients.

RESULTS

Forty-three chemoebolization procedures were performed in 34 symptomatic patients from December 1995 to August 1999. Seventeen patients had intestinal primaries (50%), seven had pancreatic primaries (20%), five had bronchial primaries (15%), and five had unknown primaries (15%). Systemic pancreastatin levels were improved or stable in 31 patients (78%). Symptoms were improved in these 31 patients (78%). Systemic serotonin levels were improved or stable in 24 patients (60%). Radiographic improvement or stability was seen in 18 patients (45%). Procedural related morbidity included pain, fevers, nausea, vomiting, and transient elevations of liver function studies in 75-100% of patients. There was one procedural related mortality (2%). Less than 20% improvement in pancreastatin levels from baseline was associated with death in five of five patients (100%). This was not observed with serotonin levels.

CONCLUSION

Measurement of serum pancreastatin levels is an easy and useful method to predict success in patients who undergo HACE plus somatostatin therapy for metastatic neuroendocrine tumors to the liver. This therapeutic approach is effective in relieving symptoms in 78% of patients, with minimal major morbidity or mortality.

NCCN Practice Guidelines for Colorectal Cancer

The NCCN Colorectal Cancer Guidelines panel believes that a multidisciplinary approach is necessary for the management of the patient with colorectal cancer. The panel endorses the concept that treatment of patients in a clinical trial has priority over standard or accepted therapy. The recommended surgical procedure for resectable colon cancer is an en bloc resection; laparoscopic surgery should be done only in the context of a clinical trial. For patients with stage III disease, 5-FU-based adjuvant therapy is recommended. A patient who has metastatic disease in the liver or lung should be considered for surgical resection if he or she is a candidate for surgery and if surgery can extend survival. Surgery should be followed by adjuvant chemotherapy. The panel advocates a conservative post-treatment surveillance program for colon and rectal carcinoma patients. Serial CEA determinations are appropriate if the patient is a candidate for aggressive surgical resection, should recurrence be detected. Abdominal and pelvic CT scans should be utilized only when there are clinical indications of possible recurrence. Patients whose disease progresses during 5-FU-based therapy should be treated with irinotecan or encouraged to participate in a phase I or phase II clinical trial.

Delirium in patients with cancer at the end of life

PURPOSE

Delirium is a common and distressing syndrome seen in patients with advanced cancer. Behavioral manifestations of delirium, such as agitation, may result in medical intervention, stress to family caregivers, and inpatient hospice admission. The purpose of this study was to examine the frequency, characteristics, and presumed causes of delirium in patients with advanced cancer.

DESCRIPTION OF STUDY

Records of all patients with cancer who were admitted to an inpatient hospice facility in 1995 were reviewed retrospectively (N = 210). Patients were classified as delirious based on the clinical judgment of the admitting physician.

RESULTS

Delirium was the third most common reason for admission (20%). Male gender (P = .04) and the presence of a primary or metastatic brain tumor (P = .03) were significant risk factors for delirium, while advanced age and primary or metastatic liver, lung, or bone cancer were not. Resolution of the agitation, the most disruptive symptom of delirium, occurred in 69% of patients before death or discharge.

CLINICAL IMPLICATIONS

Delirium is common in hospice patients with cancer and is an important cause of family distress and increased cost of care. The recognition of early clinical signs and predisposing factors should facilitate prompt diagnosis. Appropriate intervention is usually successful in alleviating the most distressing symptoms of delirium.

Intraoperative electron beam radiotherapy in recurrent colorectal carcinoma

BACKGROUND AND OBJECTIVES

The installation of a dedicated linear accelerator in a shielded operating room in 1992 allowed us to start a feasibility study of intraoperative electron beam radiation therapy (IOERT) in colorectal carcinoma.

METHODS

From March 1992 to February 1996, 28 patients with recurrent colorectal carcinoma were treated with maximal surgical resection and IOERT to the pelvis (n = 20) or paraortics (n = 8). IOERT dose ranged from 10 to 20 Gy with electron energies of 6-15 MeV. Postoperative external beam radiation therapy (EBRT) of 45-50 Gy was planned for the previously unirradiated patients.

RESULTS

IOERT was well tolerated, but 10 (70%) of 13 patients in the previously unirradiated group did not complete the EBRT per protocol. Eight patients (29%) had some morbidity including surgically related fistula distal from IOERT sites. Two patients developed pelvic pain, which can be attributed to IOERT. Three-year local control at sites treated with IOERT was 40% (53% for previously irradiated patients and 27% for previously unirradiated patients). The 3-year actuarial overall survival was 12% (17% for previously irradiated patients and 8% for previously unirradiated patients).

CONCLUSIONS

Our initial experience showed that it was feasible to treat poor prognostic colorectal cancer patients with IOERT. The morbidity observed was mainly related to extensive surgery in high-risk patients. Poor local control was obtained in patients treated with low-dose IOERT alone. Hence, previously unirradiated patients are encouraged to complete the planned EBRT or, alternatively, are considered for EBRT preoperatively or are given a higher IOERT dose (up to 20 Gy) if EBRT will not be given. Since IORT doses >20 Gy are associated with nerve toxicity, we currently add limited dose EBRT in the previously irradiated group. Patients with disease located in multiple abdominal sites are no longer considered candidates for IOERT.

Limitations with light microscopy in the detection of colorectal cancer cells

PURPOSE

The failure of light microscopy to predict individual patient survival accurately in pStage I and II colorectal carcinoma can hinder planning postoperative therapy and follow-up. This study was designed and conducted in two parts to assess the influence of relative sensitivity of the light microscope on the pathologist's ability to detect malignant cells in lymph nodes.

METHODS

The first part of the study examined the issue of sampling error as a fraction of the number of lymph node sections examined by asking the question, "Does increasing the number of sections (sampling) taken from the block increase tumor cell detection in a lymph node?" Three levels of five sections 4 to 5 microm thick separated by 15 to 20 microm were obtained from each of 494 blocks from 173 cases of pStage I and II colorectal carcinoma. A total of 1,721 lymph nodes were examined. Sections from each level were stained with hematoxylin and eosin and for the expression of cytokeratin. The second part of the study examined the relative sensitivity of the light microscope to detect tumor cells in a lymph node. To simulate lymph nodes, cell blocks were made that contained 10(6) or 10(7) mononuclear cells admixed with increasing numbers of SW480 tumor cells (0, 50, 10(2), 5 x 10(2), 10(3), and 5 x 10(3)). Three pathologists independently examined sections from ten control and ten experimental blocks.

RESULTS

Results from the first part of the study demonstrated cytokeratin-positive cells in 278 lymph nodes from 102 of 172 (59 percent) cases. These cells were identified in the first level in 177 (64 percent) as compared with the second or third level or both in 101 (36 percent) of the lymph nodes. Results from the second part of the study demonstrated an overall sensitivity of light microscopic examination of hematoxylin and eosin-stained sections to be approximately 23 percent, representing tumor cells correctly detected in 7 sections of the 30 sections containing tumor cells. The overall specificity was 87 percent or 26 sections correctly classified as lacking tumor cells of a possible 30. Immunohistochemical staining for cytokeratin expression improved sensitivity of the light microscope to detect tumor cells to 18 of 30 (60 percent) and the specificity to 30 of 30 (100 percent).

CONCLUSION

This study demonstrates several sources of variability that can induce errors in pathologic staging. These include 1) inadequate section, i.e., sampling, of lymph nodes, 2) use of only hematoxylin and eosin-stained sections, 3) samples with tumor cells below the level of detection sensitivity of the light microscope, and 4) observer variability.

Three different intraoperative radiation modalities (electron beam, high-dose-rate brachytherapy, and iodine-125 brachytherapy) in the adjuvant treatment of patients with recurrent colorectal adenocarcinoma

BACKGROUND

Intraoperative electron beam radiation therapy (IOERT) has been used in the treatment of patients with recurrent colorectal adenocarcinoma for the last 2 decades. Other intraoperative radiation modalities, such as intraoperative high-dose-rate brachytherapy (IOHDR) and intraoperative iodine-125 (125I) brachytherapy, present theoretic advantages for selected patients with recurrent colorectal adenocarcinoma. The experience of a single-institution series in which these three intraoperative radiation modalities were used in a nonrandomized manner is discussed in this report.

METHODS

Between September 1989 and January 1997, 80 patients with colorectal adenocarcinoma recurrent in the pelvis or in the paraaortic lymph nodes were treated with IOERT (28 patients), IOHDR (23 patients), or 125I brachytherapy (29 patients).

RESULTS

The overall 5-year local control rate was 26% (median = 12 months; 95% confidence interval [95%CI], 6-17). Tumors in paraaortic sites had significantly better local control than those in the pelvis (P = 0.03). The 5-year overall survival rate was 4% (median = 20 months; 95% CI, 17-23). Patients with microscopic residual disease (P = 0.02) and those treated with postoperative external beam irradiation (EBRT) (P = 0.0007) had statistically significant longer survival. Forty-one percent of the treated patients experienced complications: These were severe (Radiation Therapy Oncology Group Grade 4-5) in 19% of patients.

CONCLUSIONS

Intraoperative radiation can locally control recurrent colorectal adenocarcinoma in a select group of patients. Patients with localized relapses, microscopic residual tumor, and no distant metastases and those receiving additional EBRT are most likely to benefit from intraoperative irradiation. The authors now routinely recommend EBRT to all patients for whom it is suitable (including those who have had prior EBRT) and consider the combination of the intraoperative modalities whenever feasible.

Cellular immunotherapy for patients with metastatic colorectal carcinoma using lymph node lymphocytes localized in vivo by radiolabeled monoclonal antibody

BACKGROUND

The authors showed previously that radiolabeled monoclonal antibody (MoAb) and a hand-held, gamma-detecting probe can be used to localize tumor-reactive lymph nodes in vivo. The authors examined the feasibility, safety, and biologic effects of cellular immunotherapy using autologous cells expanded from these lymph nodes in patients with metastatic colorectal carcinoma.

METHODS

Tumor-reactive lymph nodes containing radiolabeled MoAb were localized and excised from 32 patients with metastatic, unresectable colorectal carcinoma at laparotomy. Lymph nodes were dissociated, and cells were cultured ex vivo for 10-14 days. Patients received a single infusion of autologous, expanded cells with no systemic interleukin (IL)-2.

RESULTS

A mean of 1.6 x 10(10) expanded autologous lymph node cells were infused with toxicity limited to occasional fevers or chills. The cells infused predominately were activated CD3+ T-cells that expressed genes for IL-4, IL-5, interferon-gamma, and granulocyte-macrophage colony stimulating factor (GM-CSF) by using reverse transcriptase-polymerase chain reaction. Indium-111 labeled cells were observed to traffic initially to the lungs, bone marrow, liver, and spleen. One patient on study achieved a partial response (>80% reduction), and mixed or minor responses were noted in 4 other patients. The responding patient's cell characteristics were notable for high levels of GM-CSF and IL-4 secretion on restimulation with immobilized anti-CD3 in vitro, and biopsies of the tumor were characterized by macrophage infiltration. The median survival of the cell-treated group compared favorably with a similar group of patients who underwent radioimmunoguided surgery without cell treatment (12.5 months vs. 5.8 months)

CONCLUSIONS

The infusion of cells expanded from tumor-reactive lymph nodes localized with radiolabeled MoAb in vivo is reproducible and safe and has biologic activity, even in the absence of systemic IL-2 infusion. This approach represents a novel application of MoAb technology, in that MoAbs are used not to diagnose or treat disease directly but rather to identify lymph node cells with therapeutic potential.

Iodine-125 brachytherapy in the treatment of colorectal adenocarcinoma metastatic to the liver

BACKGROUND

The liver is the site of distant failure in > 33% of patients with colorectal adenocarcinoma. Liver resection is the only potentially curative option in these patients. Patients with incompletely resected liver lesions (due to the proximity to critical vascular structures) are at high risk of dying of progressive disease in the liver. This pilot study was performed to determine whether the intraoperative implantation of iodine-125 (I-125) seeds could reduce the recurrence and improve the survival of patients with incompletely resected liver metastases.

METHODS

Fifty-six patients with unresectable or residual disease after surgical resection of liver metastases from colorectal carcinoma underwent permanent implantation with I-125 seeds to deliver 160 gray to the periphery of the target volume.

RESULTS

The 1-, 3-, and 5-year actuarial control rates of liver disease were 41%, 23%, and 23%, respectively. The 5-year actuarial control of liver disease was better for patients with a solitary metastasis (39%) than for those with multiple metastases (9%) (P = 0.04). The 1-, 3-, and 5-year actuarial overall survival rates were 71%, 25%, and 8%, respectively (median, 20 months; 95% confidence interval, 17-23). The radiation-related complications were minimal.

CONCLUSIONS

I-125 liver brachytherapy is feasible with minimal radiation-related morbidity. Good prognostic factors for long term liver control and survival are the presence of a solitary metastasis, postresection minimal residual disease requiring smaller volume implants, and no prior liver resections. Future prospective trials should be directed toward this patient population, which has the highest probability of obtaining improved results from the local dose escalation provided by brachytherapy. Adjuvant regional chemotherapy clearly is needed due to the high rate of liver recurrence and ultimate death from liver failure observed in spite of liver resection and brachytherapy.

Iodine-125 brachytherapy in the treatment of colorectal adenocarcinoma metastatic to the liver

BACKGROUND

The liver is the site of distant failure in > 33% of patients with colorectal adenocarcinoma. Liver resection is the only potentially curative option in these patients. Patients with incompletely resected liver lesions (due to the proximity to critical vascular structures) are at high risk of dying of progressive disease in the liver. This pilot study was performed to determine whether the intraoperative implantation of iodine-125 (I-125) seeds could reduce the recurrence and improve the survival of patients with incompletely resected liver metastases.

METHODS

Fifty-six patients with unresectable or residual disease after surgical resection of liver metastases from colorectal carcinoma underwent permanent implantation with I-125 seeds to deliver 160 gray to the periphery of the target volume.

RESULTS

The 1-, 3-, and 5-year actuarial control rates of liver disease were 41%, 23%, and 23%, respectively. The 5-year actuarial control of liver disease was better for patients with a solitary metastasis (39%) than for those with multiple metastases (9%) (P = 0.04). The 1-, 3-, and 5-year actuarial overall survival rates were 71%, 25%, and 8%, respectively (median, 20 months; 95% confidence interval, 17-23). The radiation-related complications were minimal.

CONCLUSIONS

I-125 liver brachytherapy is feasible with minimal radiation-related morbidity. Good prognostic factors for long term liver control and survival are the presence of a solitary metastasis, postresection minimal residual disease requiring smaller volume implants, and no prior liver resections. Future prospective trials should be directed toward this patient population, which has the highest probability of obtaining improved results from the local dose escalation provided by brachytherapy. Adjuvant regional chemotherapy clearly is needed due to the high rate of liver recurrence and ultimate death from liver failure observed in spite of liver resection and brachytherapy.

Iodine-125 brachytherapy in the treatment of colorectal adenocarcinoma metastatic to the liver

BACKGROUND

The liver is the site of distant failure in > 33% of patients with colorectal adenocarcinoma. Liver resection is the only potentially curative option in these patients. Patients with incompletely resected liver lesions (due to the proximity to critical vascular structures) are at high risk of dying of progressive disease in the liver. This pilot study was performed to determine whether the intraoperative implantation of iodine-125 (I-125) seeds could reduce the recurrence and improve the survival of patients with incompletely resected liver metastases.

METHODS

Fifty-six patients with unresectable or residual disease after surgical resection of liver metastases from colorectal carcinoma underwent permanent implantation with I-125 seeds to deliver 160 gray to the periphery of the target volume.

RESULTS

The 1-, 3-, and 5-year actuarial control rates of liver disease were 41%, 23%, and 23%, respectively. The 5-year actuarial control of liver disease was better for patients with a solitary metastasis (39%) than for those with multiple metastases (9%) (P = 0.04). The 1-, 3-, and 5-year actuarial overall survival rates were 71%, 25%, and 8%, respectively (median, 20 months; 95% confidence interval, 17-23). The radiation-related complications were minimal.

CONCLUSIONS

I-125 liver brachytherapy is feasible with minimal radiation-related morbidity. Good prognostic factors for long term liver control and survival are the presence of a solitary metastasis, postresection minimal residual disease requiring smaller volume implants, and no prior liver resections. Future prospective trials should be directed toward this patient population, which has the highest probability of obtaining improved results from the local dose escalation provided by brachytherapy. Adjuvant regional chemotherapy clearly is needed due to the high rate of liver recurrence and ultimate death from liver failure observed in spite of liver resection and brachytherapy.

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.