The Effect of Histopathological Growth Patterns of Colorectal Liver Metastases on the Survival Benefit of Adjuvant Hepatic Arterial Infusion Pump Chemotherapy.

BACKGROUND: Histopathological growth patterns (HGPs) are a prognostic biomarker in colorectal liver metastases (CRLM). Desmoplastic HGP (dHGP) is associated with liver-only recurrence and superior overall survival (OS), while non-dHGP is associated with multi-organ recurrence and inferior OS. This study investigated the predictive value of HGPs for adjuvant hepatic arterial infusion pump (HAIP) chemotherapy in CRLM. METHODS: Patients undergoing resection of CRLM and perioperative systemic chemotherapy in two centers were included. Survival outcomes and the predictive value of HAIP versus no HAIP per HGP group were evaluated through Kaplan-Meier and Cox regression methods, respectively. RESULTS: We included 1233 patients. In the dHGP group (n = 291, 24%), HAIP chemotherapy was administered in 75 patients (26%). In the non-dHGP group (n = 942, 76%), HAIP chemotherapy was administered in 247 patients (26%). dHGP was associated with improved overall survival (OS, HR 0.49, 95% CI 0.32-0.73, p < 0.001). HAIP chemotherapy was associated with improved OS (HR 0.61, 95% CI 0.45-0.82, p < 0.001). No interaction could be demonstrated between HGP and HAIP on OS (HR 1.29, 95% CI 0.72-2.32, p = 0.40). CONCLUSIONS: There is no evidence that HGPs of CRLM modify the survival benefit of adjuvant HAIP chemotherapy in patients with resected CRLM.

Adjuvant hepatic arterial infusion pump chemotherapy and resection versus resection alone in patients with low-risk resectable colorectal liver metastases - the multicenter randomized controlled PUMP trial.

BACKGROUND: Recurrences are reported in 70% of all patients after resection of colorectal liver metastases (CRLM), in which half are confined to the liver. Adjuvant hepatic arterial infusion pump (HAIP) chemotherapy aims to reduce the risk of intrahepatic recurrence. A large retrospective propensity score analysis demonstrated that HAIP chemotherapy is particularly effective in patients with low-risk oncological features. The aim of this randomized controlled trial (RCT) --the PUMP trial-- is to investigate the efficacy of adjuvant HAIP chemotherapy in low-risk patients with resectable CRLM. METHODS: This is an open label multicenter RCT. A total of 230 patients with resectable CRLM without extrahepatic disease will be included. Only patients with a clinical risk score (CRS) of 0 to 2 are eligible, meaning: patients are allowed to have no more than two out of five poor prognostic factors (disease-free interval less than 12 months, node-positive colorectal cancer, more than 1 CRLM, largest CRLM more than 5 cm in diameter, serum Carcinoembryonic Antigen above 200 µg/L). Patients randomized to arm A undergo complete resection of CRLM without any adjuvant treatment, which is the standard of care in the Netherlands. Patients in arm B receive an implantable pump at the time of CRLM resection and start adjuvant HAIP chemotherapy 4-12 weeks after surgery, with 6 cycles of floxuridine scheduled. The primary endpoint is progression-free survival (PFS). Secondary endpoints include overall survival, hepatic PFS, safety, quality of life, and cost-effectiveness. Pharmacokinetics of intra-arterial administration of floxuridine will be investigated as well as predictive biomarkers for the efficacy of HAIP chemotherapy. In a side study, the accuracy of CT angiography will be compared to radionuclide scintigraphy to detect extrahepatic perfusion. We hypothesize that adjuvant HAIP chemotherapy leads to improved survival, improved quality of life, and a reduction of costs, compared to resection alone. DISCUSSION: If this PUMP trial demonstrates that adjuvant HAIP chemotherapy improves survival in low-risk patients, this treatment approach may be implemented in the standard of care of patients with resected CRLM since adjuvant systemic chemotherapy alone has not improved survival. TRIAL REGISTRATION: The PUMP trial is registered in the Netherlands Trial Register (NTR), number: 7493 . Date of registration September 23, 2018.

Microwave Ablation in the Management of Colorectal Cancer Pulmonary Metastases.

PURPOSE: To review outcomes following microwave ablation (MWA) of colorectal cancer pulmonary metastases and assess predictors of oncologic outcomes. METHODS: Technical success, primary and secondary technique efficacy rates were evaluated for 50 patients with 90 colorectal cancer pulmonary metastases at immediate, 4-8 weeks post-MWA and subsequent follow-up CT and/or 18F-FDG PET/CT. Local tumor progression (LTP) rate, LTP-free survival (LTPFS), cancer-specific and overall survivals were assessed. Complications were recorded according to SIR classification. RESULTS: Median follow-up was 25.6 months. Median tumor size was 1 cm (0.3-3.2 cm). Technical success, primary and secondary technique efficacy rates were 99, 90 and 92%, respectively. LTP rate was 10%. One-, 2- and 3-year LTPFS were: 93, 86 and 86%, respectively, with median LTPFS not reached. Median overall survival was 58.6 months, and median cancer-specific survival (CSS) was not reached. One-, 2- and 3-year overall and CSS were 94% and 98, 82 and 90%, 61 and 70%, respectively. On univariate analysis, minimal ablation margin (p < 0.001) and tumor size (p = 0.001) predicted LTPFS, with no LTP for minimal margin ≥ 5 mm and/or tumor size < 1 cm. Pleural-based metastases were associated with increased LTP risk (p = 0.002, SHR = 7.7). Pre-MWA CEA level > 10 ng/ml (p = 0.046) and ≥ 3 prior chemotherapy lines predicted decreased CSS (p = 0.02). There was no 90-day death. Major complications rate was 13%. CONCLUSIONS: MWA with minimal ablation margin ≥ 5 mm is essential for local control of colorectal cancer pulmonary metastases. Pleural-based metastases and larger tumor size were associated with higher risk of LTP. CEA level and pre-MWA chemotherapy impacted CSS.

Perioperative complications influence recurrence and survival after resection of hepatic colorectal metastases.

BACKGROUND: Perioperative outcomes, such as blood loss, transfusions, and morbidity, have been linked to cancer-specific survival, but this is largely unsupported by prospective data. METHODS: Patients from a previous, randomized trial that evaluated acute normovolemic hemodilution during major hepatectomy (≥3 segments) were reevaluated and those with metastatic colorectal cancer (n = 90) were selected for analysis. Survival data were obtained from the medical record. Disease extent was measured using a clinical-risk score (CRS). Log-rank test and Cox proportional hazard model were used to evaluate recurrence-free survival (RFS) and overall survival (OS). RESULTS: Median follow-up was 71 months. The CRS was ≥3 in 45 % of patients; 59 % had extrahepatic procedures. Morbidity and mortality were 33 and 2 %, respectively. Postoperative chemotherapy was given to 87 % of patients (78/90) starting at a median of 6 weeks. RFS and OS were 29 and 60 months, respectively. Postoperative morbidity significantly reduced RFS (23 vs. 69 months; P < 0.001) and OS (28 vs. 74 months; P < 0.001) on uni- and multi-variate analysis; positive resection margins and high CRS also were significant factors. Delayed initiation of postoperative chemotherapy (≥8 weeks) was common in patients with complications (37 vs. 12 %; P = 0.01). CONCLUSIONS: In this selected cohort of patients from a previous RCT, perioperative morbidity was strongly (and independently) associated with cancer-specific outcome. It also was associated with delayed initiation of postoperative chemotherapy, the impact of which on survival is unclear.

A phase II trial of irinotecan (CPT-11) for unresectable biliary tree carcinoma.

BACKGROUND: Unresectable adenocarcinomas of the biliary tree have a very poor prognosis. No good chemotherapeutic regimen is available. Irinotecan has not yet been fully tested in this disease. We evaluated its activity in unresectable bile duct cancers. PATIENTS AND METHODS: Twenty-five consecutive eligible patients at our two institutions were treated with irinotecan at a starting dose of 125 mg/m2. A cycle consisted of once-a-week treatments for four consecutive weeks, followed by two weeks of rest. All patients were required to have histologically confirmed diagnosis, clinically documented metastatic or unresectable carcinoma and measurable disease. Patients were evaluated for response, toxicity, and survival. RESULTS: A total of 83 cycles of therapy were delivered. Two patients had a partial response (8%; 95% confidence interval (CI): 0%-18%) and ten additional patients had stable disease for at least two months (40%; 95% CI: 20.8%-59.2%). The therapy was well tolerated, with moderate myelosuppression and diarrhea as the main toxicities. The overall median survival was 10 months. CONCLUSIONS: Irinotecan has minimal activity in biliary tree carcinomas, but is well tolerated with appropriate supportive care, and produces occasional objective responses.

A phase II study of irinotecan in patients with advanced hepatocellular carcinoma.

BACKGROUND: Advanced hepatocellular carcinoma has a poor prognosis. In a Phase II clinical trial, two academic centers assessed irinotecan, a topoisomerase-1 inhibitor with broad spectrum clinical activity, in patients who had advanced hepatocellular cancer. METHODS: Patients who had had up to one prior chemotherapy regimen were eligible. Bidimensionally measurable disease, a good performance status, and adequate major organ function were required. At a starting dose of 125 mg/m2, irinotecan was administered weekly for 4 weeks followed by a 2 week break, which constituted 1 treatment cycle. Patients were restaged radiologically after two cycles of therapy. Dose attenuations were made as indicated for toxicity. RESULTS: Fourteen patients were enrolled over a 10-week period in 1997. There were ten males and four females. The median age was 58 years (range, 38-74 yrs). The Eastern Cooperative Oncology Group median performance status was 1 (range, 0-1). Two patients had prior chemotherapy (14%), and 1 patient (7%) had had radiation. A total of 30 cycles of therapy were delivered (median, 1; range, 1-6). Considerable toxicity was observed, mostly neutropenia, diarrhea, nausea, vomiting, and fatigue. All patients required at least one dose attenuation for toxicity. One partial response (7%; confidence interval, 0-20%) was noted to last 7 months. One patient had transient stable disease, and all others (86%) had progression of disease as their best response. CONCLUSIONS: Irinotecan had modest activity in advanced hepatocellular cancer. Toxicity was substantial, presumably reflecting impaired underlying liver function or poor ability to metabolize and eliminate the drug. The current study indicated that continued new therapy assessment is warranted for this disease.

Surgical debulking and intraperitoneal chemotherapy for established peritoneal metastases from colon and appendix cancer.

BACKGROUND: Aggressive treatment of peritoneal metastases from colon cancer by surgical cytoreduction and infusional intraperitoneal (IP) chemotherapy may benefit selected patients. We reviewed our institutional experience to assess patient selection, complications, and outcome. METHODS: Patients having surgical debulking and IP 5-fluoro-2'-deoxyuridine (FUDR) plus leucovorin (LV) for peritoneal metastases from 1987 to 1999 were evaluated retrospectively. RESULTS: There were 64 patients with a mean age of 50 years. Primary tumor sites were 47 in the colon and 17 in the appendix. Peritoneal metastases were synchronous in 48 patients and metachronous in 16 patients. Patients received IP FUDR (1000 mg/m2 daily for 3 days) and IP leucovorin (240 mg/m2) with a median cycle number of 4 (range, 1-28). The median number of complications was 1 (range, 0-5), with no treatment related mortality. Only six patients (9%) required termination of IP chemotherapy because of complications. The median follow-up was 17 months (range, 0-132 months). The median survival was 34 months (range, 2-132); 5-year survival was 28%. Lymph node status, tumor grade, and interval to peritoneal metastasis were not statistically significant prognostic factors for survival. Complete tumor resection was significant on multivariate analysis (P = .04), with a 5-year survival of 54% for complete (n = 19) and 16% for incomplete (n = 45) resection. CONCLUSIONS: Surgical debulking and IP FUDR for peritoneal metastases from colon cancer can be accomplished safely and has yielded an overall 5-year survival of 28%. Complete resection is associated with improved survival (54% at 5 years) and is the most important prognostic indicator.

Hepatic arterial chemotherapy in metastatic colorectal patients.

Hepatic metastases are a major cause of morbidity and mortality for patients with colorectal cancer (CRC). The rationale for hepatic arterial chemotherapy has both an anatomical and pharmacological basis. Several randomized clinical studies of fluoropyrimidine showed higher response rates in all trials when the drug was given as an hepatic arterial infusion (HAI) versus systemic administration. However, the studies did not accurately define survival for the following reasons: (1) some allowed a crossover; (2) some were too small; and (3) some used inadequate systemic chemotherapy. Patients who have failed to respond to previous systemic chemotherapy have an approximately 50% response rate with HAI treatment. Hepatic toxicity, especially biliary sclerosis, is the dose-limiting toxicity, occurring in 6% to 25% of patients. Adding dexamethasone to HAI fluoropyrimidine decreases the hepatobiliary toxicity. The therapeutic benefit of HAI in one study was also demonstrated by an increased time with normal quality of life. To truly define the role of regional therapy in patients with CRC confined to the liver, the current Cancer and Leukemia Group B (CALGB) study is randomizing patients to HAI versus systemic therapy without a crossover to demonstrate if HAI improves survival and/or quality of life in addition to response rates.

Evaluation of chest computed tomography in the staging of patients with potentially resectable liver metastases from colorectal carcinoma.

BACKGROUND: Chest computed tomography (CT) often is used to rule out lung metastases in patients with potentially resectable liver metastases from colorectal carcinoma. In the current study the authors evaluated whether CT of the chest was necessary in patients with a negative chest radiograph. METHODS: The authors performed a retrospective analysis of 202 patients with negative initial chest X-rays who were undergoing evaluation for potentially resectable liver metastases from colorectal carcinoma. Patients with highly suspicious pulmonary lesions on the initial chest CT scan underwent a thoracoscopy and biopsy. All patients were monitored for the development of pulmonary metastases. RESULTS: Sixty patients (30%) had a positive initial chest CT scan. Two patients were found to have metastases by comparison with prior CT scans. Seventeen patients had highly suspicious lesions that were biopsied, but only 2 were found to have pulmonary metastases; the other lesions were benign. An additional 13 of these 60 patients developed lung metastases during follow-up, 6 of whom were diagnosed in retrospect. Of the 142 patients with a negative initial CT scan, 33 (23%) developed pulmonary metastases. The rate of pulmonary metastases in both groups was not significantly different, regardless of whether the CT scans were positive or negative. CONCLUSIONS: During routine preoperative workup for liver resection, the majority of lesions appearing on chest CT scans of patients with negative chest radiographs were not malignant. The positive yield of CT-guided workup was only 10 of 202 patients (5%). Based on this review the authors question the use of chest CT scans in this setting.

Non-surgical treatment for liver metastases.

The liver is a common site for developing metastatic disease. Although any malignancy can spread to the liver, the direct passage of blood from the gastrointestinal tract to the liver via the portal circulation results in a high rate of liver metastasis from gastrointestinal tract tumours. Various radiographical tests including computed tomography and magnetic resonance imaging can detect the majority of liver metastases. Surgical resection if feasible is the treatment of choice since it produces a 5-year survival rate of about 30%. However, the majority of the patients relapse after hepatic resection, 50% relapsing in the liver. Systemic chemotherapy produces response rates of 15-30% with a median survival of 10-12 months. It is estimated that 30,000 patients each year in the USA are candidates for regional hepatic therapy. Hepatic arterial chemotherapy, hepatic artery embolization, chemoembolization, cryosurgery, ethanol injection of the tumour and radiation therapy are being investigated as potential treatment options for such patients.

Phase II trial of docetaxel (Taxotere) for untreated advanced colorectal carcinoma.

The antimicrotubule agent docetaxel (Taxotere), a semisynthetic taxoid, has demonstrated antitumor activity against colorectal cancer cell lines in vitro, and in murine tumor models. We sought to characterize its activity in a group of previously untreated patients with colorectal carcinoma. Eighteen previously untreated patients with advanced, measurable colorectal carcinoma were treated with a 60-min intravenous infusion of docetaxel with a dose of 100 mg/m2 administered every 21 days. Routine premedication with diphenhydramine was given. Patients were required to have normal organ function and a Karnofsky performance status (KPS) > or = 60%. No complete response (CR) or partial responses (PR) were observed. Median survival was 13 months, despite a median time to progression of only 1.3 months. Neutropenia was the most common dose-limiting toxicity, resulting in 5 episodes of febrile neutropenia requiring hospitalization and intravenous antibiotics. One patient experienced a grade 4 hypersensitivity reaction (HSR) requiring treatment termination. No toxic deaths occurred. Despite encouraging preclinical data, docetaxel is an inactive drug in advanced colorectal cancer when given in the dose and on the schedule examined in the present study, and has significant, although reversible, toxicities.

Role of chest CT in patients with negative chest x-rays referred for hepatic colorectal metastases.

BACKGROUND: Hepatic resection is the standard treatment for hepatic colorectal metastases. The lung represents the next most likely site, after the liver, of metastatic disease. Computed tomography (CT) of the chest is more sensitive than is chest x-ray in detecting metastatic lung lesions. However, the usefulness of chest CT in the evaluation of patients before hepatic resection remains uncertain. METHODS: One hundred consecutive patients with negative chest x-rays and potentially resectable hepatic colorectal metastases underwent chest CT. Patients with CT findings suggestive of metastatic disease were subjected to thoracotomy or video-assisted thoracic surgery (VATS) before laparotomy and attempted hepatic resection. The operative findings and clinical course were analyzed. RESULTS: Eleven of 100 patients had a positive chest CT. Four of these 11 patients had malignant lesions of the lung (three metastatic colorectal cancers and one primary lung cancer). There was no difference in median total hospital stay (8.5 days [range 7 to 13 days] vs. 8.0 days [range 3 to 49 days]), number of perioperative deaths (0 vs. 2 deaths), or long-term outcome between those patients with a positive chest CT undergoing thoracotomy/VATS and those patients with a negative chest CT. Overall, chest CT provided a positive yield of 4% and a positive predictive value of 36% for the detection of malignant lesions of the lung. CONCLUSIONS: Chest CT only minimally improved detection of malignant lesions of the lung over chest x-ray. Thoracotomy/VATS and wedge resection of lung nodules did not adversely affect outcome. The low positive yield and low positive predictive value of chest CT in the setting of a negative chest x-ray places in question the usefulness of routinely performing chest CT as part of the extent-of-disease work-up before hepatic resection.

9-Aminocamptothecin by 72-hour continuous intravenous infusion is inactive in the treatment of patients with 5-fluorouracil-refractory colorectal carcinoma.

BACKGROUND: 9-Aminocamptothecin (9AC) and its parent compound, camptothecin, have shown outstanding preclinical activity against colorectal carcinoma. Irinotecan (CPT-11), another camptothecin derivative, has demonstrated clinical activity in patients with 5-fluorouracil (5-FU)-refractory colorectal carcinoma. METHODS: The authors performed a Phase II trial of 9AC involving patients with measurable metastatic colorectal carcinoma who had progressed through only one prior regimen of 5-FU-based chemotherapy. 9AC was given initially at a dose of 59 microg/m2/hour by continuous intravenous infusion for 72 hours, with treatments repeated every 14 days. Granulocyte-colony stimulating factor was given on Days 5-12. RESULTS: Sixteen patients were treated on this trial. Fourteen were evaluable for response. Contrary to expectations, no major objective antitumor responses were observed. Eight patients experienced stable disease for a median of 4.1 months (range, 2.2-9.5 months). Toxicities, especially myelosuppression, were severe and necessitated a 15% reduction in the initial dose after the first 9 patients. Toxicities at this reduced dose remained unacceptable. CONCLUSIONS: 9AC did not demonstrate substantial activity against 5-FU-refractory colorectal carcinoma on the schedule studied. Toxicities at the doses and schedule studied were unacceptable in this patient population. Based on their results, the authors consider it unlikely that 9AC administered as a 72-hour continuous intravenous infusion will play a major role in the treatment of colorectal carcinoma.

Neutropenic enterocolitis in a patient with colorectal carcinoma: unusual course after treatment with 5-fluorouracil and leucovorin--a case report.

BACKGROUND: Neutropenic enterocolitis is observed in approximately 25% of patients with acute leukemia, but has been reported rarely in patients with solid tumors. If treatment is not initiated promptly, the mortality is high. The incidence of this disease is rising in patients with hematologic malignancies. Increasing numbers of patients with solid tumors are subject to high dose chemotherapy regimens or new drugs known to cause severe neutropenia. Therefore, the frequency of this disease can be expected to increase. METHODS: The authors report a patient with colorectal carcinoma who developed neutropenic enterocolitis after treatment with 5-fluorouracil and leucovorin. RESULTS: The patient developed the typical clinical picture of abdominal pain, diarrhea, and neutropenia. The course was complicated by a recurrence of symptoms after initially successful antibiotic therapy without the patient receiving further chemotherapy. CONCLUSIONS: This case indicates that neutropenic enterocolitis may occur in patients with colorectal carcinoma receiving 5-fluorouracil and leucovorin.

Is intra-arterial chemotherapy worthwhile in the treatment of patients with unresectable hepatic colorectal cancer metastases?

Regional chemotherapy, from a theoretical and pharmacological stand point, would seem to offer significant advantage over systemic therapy for the treatment of hepatic metastatic colorectal cancer patients. Clinical experience has shown us that the technique itself is fraught with practical problems, but over the years, specialist centres have learned to overcome many of these, making the technique safer and minimising the possibility of complications and toxicity. As a consequence, there is no doubt that high response rates can be achieved with HAI fluoropyrimidines. However, randomised data have only been obtained from small numbers of patients in suboptimally designed trials and, to date, true patient benefit in terms of either survival or quality of life has not been adequately demonstrated. In parallel with the U.S. Intergroup study, the U.K.-based MRC phase III clinical trial of regional versus systemic 5-FU/FA warrants urgent support and we would welcome collaboration with interested European and American centres. The outcome of this trial will fully define the role of HAI chemotherapy in the management of unresectable hepatic metastatic colorectal cancer, in the context of modern, modulated 5-FU.

Phase I clinical and pharmacokinetic study of irinotecan, fluorouracil, and leucovorin in patients with advanced solid tumors.

PURPOSE: To determine the maximum-tolerable dose (MTD) of fluorouracil (5FU) when given with fixed doses of leucovorin and irinotecan (CPT-11), to define the dose-limiting toxicities of this combination, and to evaluate the effect of 5FU on the pharmacokinetics of CPT-11. PATIENTS AND METHODS: CPT-11, leucovorin, and 5FU were administered in repeated 6-week cycles that consisted of weekly treatment with all three drugs for 4 consecutive weeks followed by a 2-week break. On day 1 of treatment, CPT-11 alone was given by 90-minute infusion, and pharmacokinetic sampling was performed over 24 hours. Leucovorin and 5FU were administered by brief intravenous injection on day 2. On days 8, 15, and 22, CPT-11 infusion was immediately followed by leucovorin and then 5FU. A second 24-hour pharmacokinetic sampling was performed on day 8, which permitted comparison of the pharmacokinetics of CPT-11 with and without 5FU. For the second 6-week cycle, leucovorin was administered first, followed by 5FU and then CPT-11, and a third pharmacokinetic sampling was performed. RESULTS: Forty-two patients were entered onto this trial. The CPT-11 dose was initially fixed at 100 mg/m2. Leucovorin was fixed at 20 mg/m2. 5FU doses of 210, 265, 340, 425, and 500 mg/m2 were studied. When the 500-mg/m2 dose of 5FU was found to be tolerable, this was then maintained and CPT-11 was escalated to 125 and then 150 mg/m2. This final CPT-11 dose exceeded the MTD. Neutropenia was the major dose-limiting toxicity. Diarrhea was common, but was rarely dose-limiting. Coadministration of 5FU had no substantial effect on the pharmacokinetics of CPT-11 or SN-38. Among the 38 patients with colorectal cancer, six partial responses (PRs) were seen in this predominantly 5FU-refractory patient population. CONCLUSION: 5FU does not substantially affect the metabolism of CPT-11 to its active metabolite, SN-38. The combination of CPT-11125 mg/m2, 5FU 500 mg/m2, and leucovorin 20 mg/m2 is feasible and tolerable on this schedule.

Tumor marker utility grading system: a framework to evaluate clinical utility of tumor markers.

Introduction of tumor markers into routine clinical practice has been poorly controlled, with few criteria or guidelines as to how such markers should be used. We propose a Tumor Marker Utility Grading System (TMUGS) to evaluate the clinical utility of tumor markers and to establish an investigational agenda for evaluation of new tumor markers. A Tumor Marker Utility Grading Worksheet has been designed. The initial portion of this worksheet is used to clarify the precise characteristics of the marker in question. These characteristics include the marker designation, the molecule and/or substance and the relevant alteration from normalcy, the assay format and reagents, the specimen type, and the neoplastic disease for which the marker is being evaluated. To determine the clinical utility of each marker, one of several potential uses must be designated, including risk assessment, screening, differential diagnosis, prognosis, and monitoring clinical course. For each of these uses, associations between marker assay results and expected biologic process and end points must be determined. However, knowledge of tumor marker data should contribute to a decision in practice that results in a more favorable clinical outcome for the patient, including increased overall survival, increased disease-free survival, improvement in quality of life, or reduction in cost of care. Semiquantitative utility scales have been developed for each end point. The only markers recommended for use in routine clinical practice are those that are assigned utility scores of "++" or " " on a 6-point scale (ranging from 0 to ) in the categories relative to more favorable clinical outcomes. Each utility score assignment should be supported by documentation of the level of evidence used to evaluate the marker. TMUGS will establish a standardized analytic technique to evaluate clinical utility of known and future tumor markers. It should result in improved patient outcomes and more cost-efficient investigation and application of tumor markers.

Phase I/II study of iodine 125-labeled monoclonal antibody A33 in patients with advanced colon cancer.

PURPOSE: A phase I/II study was designed to determine the maximum-tolerated dose (MTD) of iodine 125-labeled monoclonal antibody A33 (125I-mAb A33), its limiting organ toxicity, and the uptake and retention of radioactivity in tumor lesions. PATIENTS AND METHODS: Patients (N = 21) with advanced chemotherapy-resistant colon cancer who had not received prior radiotherapy were treated with a single 125I-mAb A33 dose. 125I doses were escalated from 50 to 350 mCi/m2 in 50-mCi/m2 increments. Radioimmunoscintigrams were performed for up to 6 weeks after 125I-mAb A33 administration. RESULTS: All 20 patients with radiologic evidence of disease showed localization of 125I to sites of disease. Twelve of 14 patients, who underwent imaging studies 4 to 6 weeks after antibody administration, had sufficient isotope retention in tumor lesions to make external imaging possible. No major toxicity was observed, except in one patient with prior exposure to mitomycin who developed transient grade 3 thrombocytopenia. Although the isotope showed variable uptake in the normal bowel, gastrointestinal symptoms were mild or absent, and in no case did stools become guaiac-positive. The MTD was not reached at 125I doses up to 350 mCi/m2. However, cytotoxicity assays demonstrated that patients treated with the highest dose had sufficiently high serum levels of 125I-mAb A33 to lyse colon cancer cells in vitro. Among 21 patients, carcinoembryonic antigen (CEA) levels returned to normal in one patient and decreased by 35% and 23%, respectively, in two patients; one additional patient had a mixed response on computed tomography. Additional, significant responses were observed in those patients treated with chemotherapy [carmustine [BCNU], vincristine, flourouracil, and streptozocin [BOF-Strep]) after completion of the 125I-mAb A33 study. CONCLUSION: Low-energy emission radioimmunotherapy with doses of up to 350 mCi/m2 of 125I-mAb A33 did not cause bowel or bone marrow toxicity. The modest antitumor activity in these heavily pretreated patients is encouraging because of lack of toxicity at the doses studied. The long radioactivity retention in tumors suggests that isotopes with a long half-life may have a therapeutic advantage, based on calculated dose delivery to tumor versus normal tissue. Due to the low bone marrow dose, further 125I trials with humanized mAb A33 are warranted, and controlled studies must be conducted to evaluate the combination of radioimmunotherapy and chemotherapy.