Potential pooling opportunities: cancer

The pooling of large amounts of clinical data from all available and relevant (diverse) sources in order to achieve greater statistical confidence may be appropriate for most modern and well conducted clinical investigations. However, in order to arrive at specific and meaningful conclusions, such exercises absolutely depend upon the homogeneity (or at least comparability) of the study population and therapy under scrutiny. There are currently many opportunities for pooling studies of cancer treatment. The most attractive disease situations are those with a sufficiently large number of completed randomized studies. Some to be considered are colon cancer, gastric cancer, hepatoma, ovarian cancer and lymphoma.

Behavioral and histological effects of acrylamide in rainbow trout

A histological and behavioral study was used to assess whether acrylamide produced neurotoxic effects in rainbow trout. Swimming performance of trout exposed to 0, 12.5, or 25 mg/liter acrylamide for 15 days was unaffected. Swimming performance of animals exposed to 50 mg/liter acrylamide for a similar time period was compromised by morbidity and mortality of the animals in this treatment group. The absence of dose-related histological lesions in central neurons, peripheral neurons or muscle suggested that the observed deficit in swimming performance was due to a generalized toxic response. Acrylamide treatment produced dose-related lesions in the gill and liver of rainbow trout.

The distribution of [14C]acrylamide in male and pregnant Swiss-Webster mice studied by whole-body autoradiography

Male and 13.5- and 17.5-day pregnant Swiss-Webster mice were administered 120 mg/kg [2,3-14C]acrylamide orally. The male mice were frozen 0.33, 1, 3, 9, 24, 72, and 216 hr later, and the pregnant mice at each gestational period were frozen at 3 and 24 hr. Whole-body autoradiographs from the male mice at early time intervals revealed accumulation of radioactivity in the contents of the gastrointestinal tract, liver, pancreas, testis, brain and gallbladder, and epithelia of oral cavity, esophagus, and bronchi. The distribution appears to be similar in the male and pregnant mice. Absorption from the stomach was virtually complete by 3 hr; renal and hepatic elimination was essentially complete at 24 hr. Radioactivity in the male reproductive tract appeared in the parenchyma of the testis at 1 hr, moved to the seminiferous tubules and head of the epididymis at 9 hr, and by 9 days remained only in the tail of the epididymis and the crypts of the epithelium of the glans penis. This movement parallels that of spermatids. The 13.5-day fetuses were uniformly labeled except for a slightly increased uptake in fetal brain. The distribution of radioactivity in the 17.5-day fetal tissues resembled that in maternal tissues; the remarkable exception was an intense accumulation in fetal skin. This study indicates that acrylamide is efficiently absorbed from the stomach and eliminated by the liver, kidney, and possibly the pancreas. A previously unrecognized affinity of acrylamide or a metabolic product was demonstrated for fetal skin in late gestation and for adult epithelia of oral cavity, esophagus, forestomach, and bronchi. Also, acrylamide or a metabolite appears to bind to spermatids at a specific stage near maturation.

A critical appraisal of low-dose cytosine arabinoside in patients with acute non-lymphocytic leukemia and myelodysplastic syndromes

We reviewed 53 publications reporting 751 patients with hematologic malignancies treated with low doses (5 to 20 mg/m2/d) of cytosine arabinoside (LoDAC). Of 507 patients evaluable for response, complete remission (CR) rates varied from 32% for patients with primary acute non-lymphoblastic leukemia (1 degree ANLL) to 16% for patients with hematologic malignancies secondary to previous chemotherapy or following a myelodysplastic syndrome (MDS) (2 degrees ANLL), and 16% for MDS. Median duration of CR was 9.5 months for 1 degree ANLL, and 10.5 months for both 2 degrees ANLL and MDS. Based on limited available survival data, overall median survival for these groups was 9 months, 3 months, and 15 months, respectively. Only three CRs were reported of 31 evaluable patients treated for a variety of other hematologic malignancies. CR rates for patients with 1 degree ANLL greater than or equal to 50 years old was 56%, compared with 29% less than 50 years old (P = .10). While prior chemotherapy was more common in 1 degree ANLL patients less than 50 years of age (86% v 21%; P less than .001), it did not influence response rates in those greater than 50 years of age, suggesting other biases. Hematologic toxicity was mentioned in only 33 of 53 publications, affecting 254 of 289 patients (88%), with at least 15% treatment-related deaths. LoDAC hypothetically acts as a differentiating agent; however, correlative laboratory studies were rarely performed. Cytogenetic data were available for only 15%, and in vitro studies for 10% of all patients with marked discrepancies in the interpretation of results. LoDAC is clearly cytotoxic for both malignant and normal hematopoietic cells. While large numbers of patients have been reported, the lack of well-designed clinical trials prohibits definitive conclusions as to its role as a differentiating agent. Future LoDAC studies should determine optimal dose and schedule, with clinical laboratory correlates to assess differentiation. Trials in ANLL comparing LoDAC with conventional chemotherapy, and in MDS with supportive care alone, may help identify the role of LoDAC. Until appropriate indications can be identified, LoDAC should not be routinely used in clinical practice.

Chronic toxicity and oncogenicity study on acrylamide incorporated in the drinking water of Fischer 344 rats

Male and female Fischer 344 rats were maintained on treated drinking water providing dosages of 0 (controls), 0.01, 0.1, 0.5, or 2.0 mg acrylamide/kg body wt/day for 2 years to assess the chronic toxicity and oncogenic potential of the chemical. The mean body weights of male and female rats receiving 2.0 mg/kg/day and of male rats receiving 0.5 mg/kg/day were minimally decreased when compared with controls. During the last 4 months of the study, there was an increase in mortality among male and female rats receiving 2.0 mg/kg/day. A target organ effect, characterized by degeneration of peripheral nerves, was observed in rats receiving 2.0 mg/kg/day. The incidence of several tumor types was increased in the rats receiving 2.0 mg/kg/day when compared with controls. In females, increased tumor incidences were observed in the mammary gland, central nervous system, thyroid gland-follicular epithelium, oral tissues, uterus, and clitoral gland. In males the incidence of tumors of the thyroid gland-follicular epithelium and scrotal mesothelium was increased. Male rats receiving 2.0 mg/kg/day also had increased incidence of central nervous system tumors when compared to historical controls but not when compared to concurrent controls. The only tumor incidence which was significantly increased at the 0.5 mg/kg/day level was scrotal mesothelioma. There was no statistically significant increase of any tumor type at the 0.1 or 0.01 mg/kg/day dose levels. However, the incidence of scrotal mesothelioma at the 0.1 mg/kg/day level was greater than that observed in the control group or historically reported in this laboratory.

Subepidermal vesicular dermatosis and sensory peripheral neuropathy caused by pyridoxine abuse

A woman who had ingested 2 gm of pyridoxine (vitamin B6) daily for 2 years for menstrual water retention developed a subepidermal vesicular eruption on the dorsa of the hands and toes, as well as a sensory peripheral neuropathy. The cutaneous and neurologic manifestations subsided about 2 months after discontinuation of the pyridoxine. The possible relationship of subepidermal vesicular eruptions caused by pyridoxine abuse to epidermolysis bullosa acquisita is discussed.

Gonadotropin hormone-releasing hormone analogues: a new therapeutic approach for prostatic carcinoma

The introduction of potent analogues of gonadotropin hormone-releasing hormone (GnRH) into clinical practice and their use in patients with metastatic prostatic carcinoma provides an effective alternative to the exogenous administration of pharmacologic doses of estrogens or surgical castration. Their advantages over estrogens are primarily related to a lower incidence of cardiovascular toxicity and gynecomastia. Their choice over orchiectomy is based on cosmetic and psychologic factors since their endocrine effects and clinical benefits are virtually the same. In this review, we describe the current experience with GnRH analogues in the treatment of prostatic carcinoma and discuss their use in the context of other endocrine manipulations. GnRH analogues act on the pituitary and indirectly affect gonadal function, and represent an opportunity for combination with other compounds capable of suppressing or interfering with the effects of circulating and androgens. The availability of several new compounds affecting different aspects of androgen metabolism provides promise for rational drug selection and testing.

A reevaluation of nonhormonal cytotoxic chemotherapy in the treatment of prostatic carcinoma

The palliative role of nonhormonal cytotoxic chemotherapy in the treatment of endocrine-resistant prostatic carcinoma has not been established. Conventional means of quantifying tumor response are most frequently not applicable in this disease because of the lack of measurable objective parameters to allow for a reliable estimation of antitumor effects. While this problem is not unique to prostatic carcinoma, this review illustrates its magnitude in this disease. Only approximately 5% of patients studied fulfill the various criteria for complete response (CR), partial response (PR), or both, while the vast majority of patients reported as responders are actually in the stable disease category. Stable disease is highly questionable as an indicator of antitumor response and should not be used as a criterion for response in conventional phase II studies unless it is convincingly demonstrated that it occurs as a result of treatment. A study design that may allow a more reliable assessment of the value of the stable disease category is described in the text. More effective means for assessing tumor responses and better instruments to measure aspects of quality of life are needed. Review of several prospective randomized clinical trials showed that no treatment program tested during the last decade resulted in a survival advantage when compared with a concurrently treated control group. Furthermore, in two such trials, four different single chemotherapeutic agents widely used in the treatment of this disease (cyclophosphamide, 5-fluorouracil, estramustine phosphate, and streptozocin) either alone or in combination, did not produce any prolongation of survival when compared to a no chemotherapy (standard treatment) control arm. Survival curves for endocrine-resistant patients fall within a relatively narrow and possibly predictable range that may be used as an additional endpoint in conjunction with response (CRs and PRs only) in phase II trials. More definitive evidence of therapeutic efficacy in this disease should derive from phase III trials using survival as one of the major endpoints. Because of the poor results observed with chemotherapy thus far, we suggest that the appropriate control arm for phase III testing in endocrine-resistant patients continues to be a no chemotherapy control arm consisting of a best symptomatic care or a uniformly applied second-line endocrine manipulation.

Phase II study of sequential methotrexate and 5-FU plus mitomycin and leucovorin in patients with disseminated large bowel cancer: a Northern California Oncology Group study

Sequential methotrexate (MTX) and 5-FU plus leucovorin and mitomycin (MMC) was given to 52 patients with disseminated, measurable colorectal cancer. Complete and partial responses were seen in 19 of 49 (39%) evaluable patients. Nine additional patients achieved a minimal response. Median overall survival was 8.8 months, while that for patients objectively responding was 13.6 months. This study utilized a MTX exposure period of 12 hours prior to 5-FU. In comparison to other trials utilizing sequential MTX and 5-FU, the addition of MMC to the regimen may improve the response rate but increases the incidence of adverse effects, particularly myelosuppression and renal toxicity. This phase II trial suggests that sequential MTX and 5-FU plus leucovorin and MMC is an active combination therapy and warrants further comparative trial in patients with large bowel cancer.

Hepatic arterial chemotherapy for colorectal cancer metastatic to the liver

Hepatic metastases of colorectal origin are resistant to radiation and immunotherapy. Traditional intravenous chemotherapy produces responses in 10% to 30% of patients, and surgical resection is feasible in approximately 20% of patients who have a solitary or unilobar lesion. Infusion of cytotoxic agents into the hepatic artery, introduced 2 decades ago, is the most promising form of therapy for unresectable hepatic metastases. Fluorouracil, floxuridine, and mitomycin have been most commonly administered by hepatic arterial infusion. The recent development of a totally implantable pump has allowed prolonged ambulatory infusion of chemotherapeutic agents into the hepatic artery. We review the recent data on the pharmacology, therapeutic outcome, administration techniques, and complications of hepatic arterial chemotherapy. Future trials in this area should use uniform stratification variables and standardized criteria for evaluating response, time to progression, and survival.

The distribution of [14C]caprolactam in male, female and pregnant mice

The distribution of [14C]caprolactam was studied by whole-body autoradiography in male, female and 14.5-day-pregnant mice. This technique does not allow translocation or removal of soluble compounds from the sites of localization. Pregnant mice were frozen 20 min and 1, 3, 9 and 24 hr after oral administration of the compound. The non-pregnant mouse was frozen 3 hr after oral dosing; two male mice were frozen 20 min and 9 hr after intravenous administration. Radioactivity was rapidly absorbed from the stomach and distributed throughout the entire animal, including the foetuses. There was efficient elimination by the kidney and liver. Material secreted by the liver into bile and intestinal contents appeared not to be reabsorbed via the enterohepatic circulation. The kinetics of distribution and elimination appeared to be the same in male, female and pregnant animals. The only sites of retention of radioactivity after 24 hr were the umbilical cords, amnion, yolk sac, maternal lens, maternal Harderian gland and maternal liver. The distribution into and removal from the foetuses was typical of molecules that diffuse freely across the placenta. There was no retention of radioactivity in any foetal tissue. With the possible exception of some residual activity in the nasal epithelium, no localization was seen that would suggest a site of toxic action of caprolactam.

Metabolism, disposition and excretion of [14C]melamine in male Fischer 344 rats

The metabolism, excretion and disposition of melamine were determined after administration of a single oral dose of 0.025 mCi (0.38 mg) [14C]melamine to adult male Fischer 344 rats. Within the first 24 hr, 90% of the administered dose was excreted in the urine. Negligible radioactivity appeared in breath and faeces. There was little difference in blood, liver or plasma concentrations of 14C, suggesting that melamine distributes in body water. The only organs showing radioactivity levels much higher than plasma were the kidney and bladder. The bladder level was by far the highest, a finding probably due either to back diffusion from urine or to contamination of bladder tissue with urine. Virtually no residual radioactivity was observed in tissues examined at 24 hr or later. The elimination-phase half-life calculated from plasma data, 2.7 hr, was in good agreement with the urinary-excretion half-life of 3.0 hr. The renal clearance of melamine was 2.5 ml/min. Radioactivity in plasma or urine co-chromatographed with that of the dosing solution, indicating that melamine is not metabolized in the male Fischer 344 rat.

Primary hepatocellular cancer--present results and future prospects

Hepatocellular cancer is an enormously difficult clinical problem. This review provides an overview of selected basic and applied aspects of the care of hepatoma patients. Important pathophysiologic and prognostic features are now recognized. Initially, chemotherapy programs focused on the use of those agents commonly employed for gastrointestinal neoplasms (fluoropyrimidines, anthracyclines and alkylators). When employed as a conventional intravenous bolus, only Adriamycin is a reproducibly effective agent. However, because of the unique dual vascular supply of the liver and tumor, the use of intraarterial (IA) infusion chemotherapy has become more popular. In this regard, of promise are the application of IA FUDR and Adriamycin, the use of totally implanted infusion systems, and hepatic artery embolization. Furthermore, combinations of whole liver irradiation with chemotherapy seem efficacious. New directions for the therapy of hepatoma patients will focus on superior drug-radiation combinations, exploration of isotopic immunoglobulin, and hormonal therapy. There is currently no standard therapy for hepatoma patients, but prospects for the future have never been so bright.

Chemotherapy of disseminated gastric cancer. A joint effort of the Northern California Oncology Group and the Japanese Gastric Cancer Chemotherapy Group

A consortium of Northern California and Japanese investigators studied 142 patients with advanced gastric adenocarcinoma. Patients were randomized to one of two combination chemotherapy programs in each nation (one common therapy shared and one therapy unique to each nation). Median duration of survival ranged between 5 and 45 weeks, depending on performance status, extent of disease, and chemotherapy program. More importantly, there was considerable comparability with respect to toxicity and outcome between patients in the US and Japan. Overall median survival was 26 weeks for Japanese and 27 weeks for US patients. This study helps provide the basis for future comparative multinational trials.

How accurate are computed tomographic scans in assessment of changes in tumor size?

The computed tomographic scan plays an integral part in the diagnosis and management of tumors; however, its potential has not yet been fully exploited. With a computer-assisted volume determination method, the reproducibility of derived volume calculations was assessed, and radiologists' standard interpretations of interval change on serial scans were compared with the investigators' calculations of tumor volume change. Interobserver reproducibility of tumor volume calculations of the mean of two repeated volume determinations was satisfactory (mean of 3 percent, median of 1 percent). There were 29 comparisons (47 scans of 19 patients with liver tumors) of computed tumor changes with the radiologists' computed tomographic reports of consecutive scans. In only 41 percent (12 of 29) of the cases did the radiologists' interpretations and the computer-assisted volume determinations agree. It is concluded that objective computer-assisted volume determination provides a potentially more sensitive assessment of tumor change and that such precise, specific, reproducible determination of tumor volume should further clinical research and improve patient care.

Effect of dietary administration of the rubber curative trithiocyanuric acid to the rat

Trithiocyanuric acid (TCY) is a rubber curative of low oral and dermal toxicity and with a low potential for eye and skin irritation. This study determined the effects of TCY on Sprague-Dawley rats at levels of 0.0, 625, 2500 and 5000 ppm in the diet for 2-30 days. While there were some effects on body-weight gain and survival at the higher levels of intake, the main effects concerned unusual lesions of the pinna and the distal portions of the tail. Purplish discolorations of the ear margin and tip of the tail were noted in some animals on the 2500- and 5000-ppm diets. The tail lesion was evident microscopically at day 16 only in the 5000-ppm group and consisted of congestion of the vasculature in the subepidermal connective tissue with focal necrosis of the distal tail segment. By day 16 the ear lesion was also microscopically identifiable only in the group on the 5000-ppm diet. It was found in 33% of these animals at day 8 and in 67% at day 16 and consisted of a localized cellulitis characterized by moderate infiltrates of polymorphonuclear leucocytes in the epidermal and subepidermal tissues. The lesions caused by high levels of TCY were apparently site-specific, since histopathological examination of selected internal organs did not detect any lesions. The no-effect levels determined were 2500 ppm for microscopic lesions during an 8-16-day treatment period and 625 ppm for gross pathological lesions in a 30-day feeding study.

5-Fluorouracil + Oncovin + Adriamycin + mitomycin C (FOAM): an effective program for breast cancer, even for disease refractory to previous chemotherapy. A Northern California Oncology Group (NCOG) Study

One hundred and thirty-one patients (118 evaluable) with disseminated breast cancer were treated with a combination of 5-fluorouracil + Oncovin + Adriamycin + mitomycin C (FOAM). The objective response rate for 82 evaluable patients whose disease was refractory to previous CMF or L-PAM chemotherapy was 35%; that for 36 evaluable patients who had not previously received chemotherapy, 56%. The hematologic toxicity of this therapy was generally mild and acceptable. It is believed that FOAM is an effective therapy for patients whose tumors are resistant to CMF.

Hepatic intraarterial chemotherapy--current status and future prospects--"If you have a short sword, take a step forward"

The use of hepatic intraarterial (IA) chemotherapy for patients with unresectable liver malignancy has become an increasingly popular mode of therapy. Advances in the understanding of antineoplastic pharmacology, catheter placement technique, and infusion pump design have renewed interest in this approach. Despite inadequacies of the historical data, it appears that IA therapy may be superior to conventional intravenous therapy for patients who have disease limited to the liver, especially from colorectal and hepatocellular malignancies. Unanswered are questions concerning which is the best drug (or drugs) for IA therapy, how to properly integrate IA therapy with surgery and radiation, and how to select patients likely to respond. This renovated technology offers a bright promise for the future of clinical oncology.