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F Meyskens

Publications and source records attributed to F Meyskens.

15 recordsLinked to original sources
PubMed1999

Beta-carotene produces sustained remissions in patients with oral leukoplakia: results of a multicenter prospective trial.

BACKGROUND: Beta-Carotene has been reported to produce regressions in patients with oral leukoplakia, a premalignant lesion. However, previous studies have all been of short duration, with clinical response as the end point. OBJECTIVE: To evaluate the duration of response and the need for maintenance therapy in subjects who respond to beta-carotene. METHODS: In this multicenter, double-blind, placebo-controlled trial, subjects were given beta-carotene, 60 mg/d, for 6 months. At 6 months, responders were randomized to continue beta-carotene or placebo therapy for 12 additional months. RESULTS: Fifty-four subjects were enrolled in the trial, with 50 being evaluable. At 6 months, 26 subjects (52%) had a clinical response. Twenty-three of the 26 responders completed the second, randomized phase. Only 2 (18%) of 11 in the beta-carotene arm and 2 (17%) of 12 in the placebo arm relapsed. Baseline biopsies were performed in all patients, with dysplasia being present in 19 (38%) of the 50 evaluable patients. A second biopsy was obtained at 6 months in 23 subjects who consented to this procedure. There was improvement of at least 1 grade of dysplasia in 9 (39%), with no change in 14 (61%). Nutritional intake was assessed using food frequency questionnaires. There was no change in carotenoid intake during the trial. Responders had a lower intake of dietary fiber, fruits, folate, and vitamin E supplements than did nonresponders. Beta-carotene levels were measured in plasma and oral cavity cells. Marked increases occurred during the 6-month induction. However, baseline levels were not restored in subjects taking placebo for 6 to 9 months after discontinuation of beta-carotene therapy. CONCLUSIONS: The activity of beta-carotene in patients with oral leukoplakia was confirmed. The responses produced were durable for 1 year.

Aged↗
PubMed1996

Adherence enhancers in pill-related clinical trials: a health behavior in cancer prevention model-based approach.

Preventing non-adherence and treating adherence failure are important to consider in designing community-based clinical trials. The approach and methods for managing adherence are vital. This paper describes a practical and theoretically-based strategy for managing adherence in a small cancer prevention trial with subjects (n = 40) taking a non-steroidal anti-inflammatory drug, piroxicam. Average daily pill intake adherence was exceptionally high (97.4%) as measured by self-report calendar. Thus, the generalized adherence enhancement approach used in this study may have been a related factor, although statistical model-testing was not possible in this small trial. The generalized intervention took into account factors such as the potential barriers and benefits of being in the study, self-efficacy and satisfaction with the participant/staff relationship. These and other theoretical variables were incorporated into an overall adherence strategy that is discussed.

Aged↗
PubMed1995

Design and recruitment for retinoid skin cancer prevention (SKICAP) trials. The Southwest Skin Cancer Prevention Study Group.

The retinoid skin cancer prevention (SKICAP) trials are a set of double-blind, randomized, placebo-controlled clinical trials. The SKICAP-actinic keratoses (AK) trial tests the hypothesis that daily supplementation of retinol (25,000 IU) for 5 years reduces the incidence of skin cancers in high-risk individuals, those with a history of greater than ten clinically or pathologically diagnosed AK and, at most, one prior pathologically confirmed cutaneous squamous cell carcinoma (SCC) or basal cell carcinoma (BCC). The SKICAP-SCC/BCC (S/B) trial tests the hypothesis that daily supplementation of retinol (25,000 IU) or 13-cis-retinoic acid (5 or 10 mg) for 3 years reduces skin cancer incidence in very high-risk individuals, those with a history of at least four pathologically confirmed SCCs or BCCs. Between 1984 and 1988, 2800 participants were enrolled at two clinics on the SKICAP-AK trial; and between 1985 and 1990, a total of 719 participants were enrolled at four clinics on the SKICAP-S/B trial. The initial recruitment strategy was referral by dermatologists, but low accrual necessitated the use of other strategies to achieve enrollment goals, which included involving additional clinics and using paid trial-specific advertisements in print and electronic media. Thirteen % of the SKICAP-AK participants and 36% of the SKICAP-S/B participants were enrolled through dermatologist referral, whereas paid advertisements resulted in enrollment of 87% of SKICAP-AK and 43% of SKICAP-S/B participants. A population-based skin cancer registry was used to identify and enroll the remaining 21% of the SKICAP-S/B participants.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Risk factors for Barrett's oesophagus: a life history approach to behavioural assessment in the distant past.

Little is known about the aetiology of Barrett's oesophagus, a condition in which columnar epithelium replaces normal squamous epithelium above the juncture of the oesophagus with the stomach. An exploratory retrospective study of males from the Tucson Veteran's Affairs Medical Center (Tucson, AZ, USA), looking at 22 Barrett's cases and 22 controls, was undertaken to: (1) determine whether risk factors previously reported for squamous oesophageal cancer were also potential risk factors for Barrett's oesophagus; and (2) explore which of several retrospectively determined dietary factors would permit maximum discrimination of Barrett's cases from controls. Because of the recognized difficulty with retrospective dietary assessment, an intensive interview-based life history approach was developed to assess behavioural factors throughout adulthood. We examined the dose-response relationship involving questions (1) and (2) separately for subjects with lesions less than or greater than 7 cm in length. A literature-based oesophageal cancer risk factor score (including use of tobacco and intakes of alcohol, fat, vitamin A, linoleic acid and protein) discriminated cases from controls. Alcohol consumption alone discriminated patients with lesions < 7 cm in length from controls, and a more complex risk factor score (including tobacco use, alcohol, fat, fruits and vegetables) discriminated patients with lesions > 7 cm in length from controls.

Adult↗
PubMed1994

Comparative exposure ratios: a non-parametric, multifactor technique for case-control studies.

The odds ratio in a two-by-two table is widely used in case-control studies to measure association between disease and a binary risk factor. In this article we propose a more general measure of association, the comparative exposure ratio (CER), which is the ratio of the number of case-control pairs where the case has greater exposure divided by the number where the control has greater exposure. In simple cases, the CER is an odds ratio or a weighted combination of odds ratios. In more general cases, a CER continues to measure association even when an odds ratio computation is not feasible. Moreover, CERs improve on odds ratios in several ways: they do not require binary risk factors, or a choice of the scale of measurement of continuous risk factors; they make it possible to investigate multiple risk factors simultaneously, without multivariate parametric assumptions; they also can be used to detect patterns that might indicate possible causal pathways. We illustrate how various choices of the definition of 'greater exposure' make the CER a powerful and flexible tool. We give expressions for confidence intervals for CERs, and verify in a pilot simulation that they are valid. Finally, we illustrate with a case-control study of cervical dysplasia how exploratory inference using CERs can be carried out.

Case-Control Studies↗
PubMed1993

Oral cancer prevention: the case for carotenoids and anti-oxidant nutrients.

The most convincing evidence for a preventive role for any modality is obviously demonstration of incidence reduction produced by that modality. However, cancer prevention trials with cancer incidence as an endpoint have logistic problems rendering them essentially impossible to conduct for most malignancies. Hence a workable strategy often involves analysis of other, indirect lines of evidence to reach conclusions. For oral cancer, dietary epidemiologic evidence points to a protective role for foods rich in carotenoids. Other anti-oxidants, such as vitamin C, are also implicated. Similarly, laboratory evidence points to a carcinogenesis inhibitory role for both retinoids and carotenoids. Clinical studies have targeted premalignant lesions, i.e., oral leukoplakia. For over two decades the efficacy of retinoids, natural and synthetic, has been known. Nevertheless, it has been difficult to translate this into a recommendation for prevention because of the toxicity of retinoids. The synthetic retinoid most often used in these trials is 13-cis-retinoic acid. This compound is toxic even at very low doses (0.1 mg/kg/day), particularly when given over several weeks to months. Hence, although effective, it cannot be advocated for prevention or oral cavity cancer. Studies with nontoxic antioxidants, such as beta-carotene, are much more recent. Early results are promising in that beta-carotene, alone or in combination with other nutrients, can reverse oral leukoplakia without toxicity in short-term trials. Studies currently under way will demonstrate whether durable remissions can be obtained using this strategy. It should be emphasized that such long-term trials are problematic to conduct with the toxic retinoids because the risks of prolonged exposure to them outweighs the chance of cancer development in the usual leukoplakia lesion.

Animals↗
PubMed1990

Phase II study of recombinant alpha-interferon in malignant melanoma.

Ninety-seven evaluable patients with measurable, advanced, malignant melanoma were treated with recombinant alpha interferon in a cooperative phase II efficacy trial, whose primary objective was to estimate the response rate. Interferon (rIFN alpha-2a, Roferon-A) was injected subcutaneously daily for 70 days. Dose was escalated in four steps from three million units to 36 million units over ten days. Eight patients responded objectively and six patients (6%) had a complete response. The median duration of complete response was 11 months. Patients achieving complete response had only cutaneous, nodal, or pulmonary disease; some had extensive prior therapy; some could tolerate no more than three million units per day. Few patients could tolerate the target dose of 36 million units daily for 70 days. Limiting toxicity was primarily fatigue. Interferon in tolerable doses is effective in a small subset of patients with melanoma. Comparison of published trials of dacarbazine and recombinant alpha interferon indicates the two drugs have similar activity.

Adult↗
PubMed1989

Phase II trial of fenretinide [N-(4-hydroxyphenyl) retinamide] in myelodysplasia: possible retinoid-induced disease acceleration.

To determine the activity of fenretinide in patients with myelodysplastic syndromes, 15 patients were treated (300 mg/d starting dose, escalated to 400 mg/d) for a 12-week course. No responses were observed in 14 evaluable patients. Exacerbation of thrombocytopenia occurred in one patient with chronic myelomonocytic leukemia, who succumbed to an intracerebral hemorrhage after 3 weeks of treatment. Two patients with long-standing stable sideroblastic anemia experienced interval leukemic progression. In one patient, clinical features of chronic myelomonocytic leukemia appeared, characterized by a striking rise in peripheral monocyte count (0.49 x 10(9)/l to 10.8 x 10(9)/l) and hepatosplenomegaly, which resolved promptly after cessation of treatment. The second patient experienced evolution into acute myelomonocytic leukemia with cytogenetic progression. The drug was well tolerated with no patient having to discontinue treatment because of toxicity. We conclude that fenretinide lacks clinical efficacy in the treatment of myelodysplasia and in some patients may enhance leukemic progression.

Acute Disease↗
PubMed1989

Effect of oral isotretinoin on dysplastic nevi.

We previously reported a favorable histologic response of dysplastic nevi to topical tretinoin in three patients. To investigate the anticancer and cancer preventive effects of retinoids we have examined the effect of systemic isotretinoin on dysplastic nevi. After confirmatory baseline biopsies, eleven patients with the dysplastic nevus syndrome were treated with oral isotretinoin, 40 mg twice a day for 4 months. At completion of therapy, at least three previously identified and photographed clinically typical dysplastic nevi were rephotographed and removed for histologic evaluation. Eight patients completed the full course of medication. There were no clinical changes in the dysplastic nevi in these patients. Posttherapy biopsy specimens in six volunteers revealed most of the remaining lesions to be dysplastic nevi. The majority of lesions biopsied in two subjects showed normal, benign nevi only. This proportion of clinically typical dysplastic nevi that prove to be normal nevi histologically (28%) is not significantly different from that reported by others. Oral isotretinoin does not appear to have a significant biologic effect on the clinical or histologic appearance of dysplastic nevi in the treatment schedule employed.

Administration, Oral↗
PubMed1976

The role of orchiectomy in the management of advanced male breast cancer.

Nine men with advanced carcinoma of the breast were evaluated after orchiectomy at the National Institutes of Health over 19 years. Of patients followed for greater than one year, five had complete remissions, one had a partial remission, and two patients did not respond to orchiectomy. The average disease-free interval was 20 months; the average survival from the time of orchiectomy in those who responded was 55.8 months and in nonresponders was 26.7 months. Orchiectomy appears to be a safe and effective way to produce an objective response and prolong survival in over 50 percent of men with advanced breast cancer.

Adult↗