Primary and Secondary Prevention of Lung Cancer: an International Association for the Study of Lung Cancer workshop.
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Biomedical subjects
Publications and source records attributed to W K Hong.
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Acute blindness or seizures are usually the first signs of central neurotoxicity from cisplatin. We report a case of subacute neurotoxicity caused by cisplatin. Progressive encephalopathy and partial loss of vision were the main observed signs. This condition was completely reversible upon cisplatin discontinuation, as is usually the case with acute central neurotoxicity.
Screening examinations were conducted at a Chinese community health fair in Houston, Texas, to identify individuals with oral leukoplakia for a chemoprevention trial of oral-cavity squamous cell carcinoma. All 161 volunteer participants were interviewed regarding age, smoking habits, and betel-nut and alcohol use. The screening included an examination of the oral cavity, oropharynx, and neck. One participant had a 1-mm area of oral leukoplakia on the right lateral surface of the oral tongue. Eighteen participants had other head and neck abnormalities. Only 12 participants (7.5%) were active smokers, and eight (5%) reported a prior history of smoking. One participant reported prior betel-nut use. The mean age was 55 years. The authors conclude that a venue such as this has a low yield for screening and recruitment of high-risk individuals for chemoprevention of oral-cavity squamous cell carcinoma, that generally health-conscious individuals attend health fairs, and that only a small percentage volunteer for oral screening.
BACKGROUND: Recurrent squamous cell carcinoma of the head and neck is poorly responsive to most chemotherapy regimens. Carboplatin and bleomycin are effective single agents with non-overlapping toxicity; therefore, we sought to explore the efficacy of this regimen in a phase II study. In the second stage of the study, patients who did not respond to carboplatin and bleomycin were given treatment with cisplatin and 5-fluorouracil (5-FU). PATIENTS AND METHODS: Patients with recurrent squamous cell carcinoma of the head and neck were treated with carboplatin 400 mg/m2 followed by bleomycin 15 units intravenously as a continuous infusion for 4 days. Patients with no tumor response after 3 cycles of carboplatin and bleomycin were crossed-over to receive cisplatin 100 mg/m2 and 5-FU 1000 mg/m2/day continuous infusion for 5 days. RESULTS: Among the 20 carboplatin-bleomycin patients evaluable for toxicity, no cases of grade 4 granulocytopenia were reported and grade 3 or 4 thrombocytopenia developed in only three patients. Three partial responses occurred among the 19 patients (16%) [95% C.I. 0% to 32%] evaluable for response to carboplatin-bleomycin. None of the 11 patients crossed-over to cisplatin and 5-FU had a major response. CONCLUSION: The combination of carboplatin and bleomycin is well tolerated in patients with recurrent head and neck cancer, but the activity does not appear to be superior to the activity of either agent alone. Patients who did not respond to carboplatin and bleomycin were also resistant to the cisplatin and 5-FU regimen.
Recent strides in epidemiology (mutagen sensitivity assays) and basic molecular study of head and neck carcinogenesis are advancing chemoprevention in the head and neck. The clinical preventive activity of retinoids, the most studied and most active chemopreventive agents in this region, has been established in six randomized head and neck trials. Ongoing translational study of the p53 gene, nuclear retinoid receptors, and other cellular and molecular biomarkers will be necessary to achieve continuing progress in head and neck cancer chemoprevention.
PURPOSE: All-trans retinoic acid (RA) induces accelerated plasma all-trans RA clearance, presumably via cytochrome P450 enzymes. This accelerated metabolism has been shown to be inhibited in the short term by the cytochrome P450 inhibitor ketoconazole. This study was conducted to evaluate the efficacy of ketoconazole in maintaining plasma all-trans RA levels over time. PATIENTS AND METHODS: Using a randomized crossover study design, we randomly assigned six patients to receive all-trans RA (45 mg/m2 orally twice per day for 14 days of a 21-day cycle) for cycle 1 and the same dose of all-trans RA plus ketoconazole (400 mg orally for one dose, then 200 mg orally three times per day for 14 days) for cycle 2, and seven patients to receive the same treatment in the reverse order. Plasma all-trans RA levels were measured during the initial 8-hour period after all-trans RA ingestion on days 1 and 15 of cycles 1 and 2. RESULTS: There was a marked decrease in plasma all-trans RA levels after 14 days of treatment, as measured by the area under the concentration-time curve (AUC), regardless of whether ketoconazole was given (from a baseline value of 857 to 44 ng/mL/h; P = .025) or not (from 1,355 to 308 ng/mL/h; P = .123). This lack of effect on plasma all-trans RA levels was not due to inadequate plasma ketoconazole levels. Ketoconazole administration was associated with more toxicity. No objective tumor responses were observed. CONCLUSION: Ketoconazole does not appear to maintain adequate plasma all-trans RA levels over time.
PURPOSE: Mutation of the p53 gene is one of the most common genetic abnormalities found in lung cancer. The purpose of this study was to evaluate the prognostic value of p53 oncoprotein expression in patients with non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: We studied 156 resected primary NSCLCs by the immunohistochemical staining technique, using the p53 antibody DO7. There were 81 adenocarcinomas, 16 large-cell carcinomas, and 59 squamous cell carcinomas; stages were I in 67, II in 30, and III in 59 cases. For each tumor, the percentage of p53 positivity was calculated by scoring a minimum of 1,000 cells on an arbitrary intensity scale of 0 to 3+. RESULTS: Overall, 103 (66%) tumors expressed p53 in more than 0.1% of cells, and squamous cell carcinomas tended to express more p53 than adenocarcinomas. Since 50% positivity marked the most distinct change in overall survival duration (P = .0008), we divided the cases into three groups, as follows: p53-negative (< or = 0.1%, n = 53), low p53 (0.1% to 50%, n = 54), and high p53 (> 50%, n = 49). Overall, patients in the high-p53 group survived longer than those in the low or negative groups, with respective median survival durations of more than 65, 26, and 33 months (P = .002). The survival difference among the three groups was statistically significant for non-squamous cell (P = .008), but not for squamous cell (P = .17) carcinomas. Among lymph node-negative patients, the survival difference between groups was not statistically significant. However, among lymph node-positive patients (n = 78), more than 65% of the high-p53 group survived for more than 70 months, while the median survival durations for the low and negative groups were 21 and 18 months, respectively (P = .001). A Cox regression analysis with multiple covariates showed that p53 positivity in more than 50% of tumor cells was an independent prognostic factor for better outcome. CONCLUSION: These results suggest that high expression of the p53 oncoprotein is a favorable prognostic factor in a subset of patients with NSCLC.
Treatment of lung cancer remains frustrating. Most patients with lung cancer are not candidates for curative therapy, and new therapies have not made a substantial impact on survival. Consequently, some clinical investigators have focused their efforts on developing prevention strategies. Chemoprevention, the administration of agents to block or reverse carcinogenesis, is being investigated in ongoing trials. Studies of chemoprevention in lung cancer have included trials to reverse premalignant lesions such as sputum atypia or squamous metaplasia of the bronchial epithelium. Clinical trials of lung cancer prevention have often studied groups of participants with tobacco or asbestos exposure. Other clinical trials are being conducted among patients who have been treated for an early-stage lung cancer. As the result of diffuse epithelial injury, these patients are at very high risk for developing second primary tumors, predominantly in the lungs and upper aerodigestive tract. It is our hope that these studies may establish a new strategy for preventing lung cancer.
This article describes two cases of multifocal synchronous cell squamous cell carcinoma in high-risk patients. The initial presentation in both instances was an erythroplakic oral lesion. The importance of the team approach between the dentist and the oncologist for quality patient care is underscored.
The prognosis for patients with recurrent or metastatic squamous cell cancer of the head and neck is poor. Chemotherapy has not significantly improved survival. New agents and regimens are being developed in hopes of improving the outcome for these patients. A phase I/II trial using a combination of paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ), cisplatin, and ifosfamide is being performed. The phase I portion is completed and reported here. Granulocytopenia was the dose-limiting toxicity. Overall, the regimen was well tolerated. Major responses were observed in four of 10 evaluable patients in the phase I study. The phase II trial is ongoing.
Clinical trials have suggested that retinoid chemoprevention prevents the development of second primary tumors following head and neck or non-small-cell lung cancer. The findings of these initial studies are now being evaluated in large multi-institution chemoprevention trials. If successful, these ongoing trials will establish the clinical role of retinoids in lung cancer prevention. The findings of these trials may also lead to strategies for primary lung cancer prevention. Until the results of these studies become available, however, lung cancer chemoprevention remains an experimental approach. The recent unexpected findings of increased lung cancer incidence in a beta-carotene study in Finnish smokers stresses the importance of establishing the efficacy of chemoprevention agents in carefully conducted clinical trials.
Six phase II studies have been conducted in the United States and Europe using docetaxel (Taxotere; Rhone-Poulenc Rorer, Antony, France) for advanced non-small cell lung cancer. One hundred eighty chemotherapy-naive patients in four studies and 88 patients who failed prior platinum-containing chemotherapy in two studies were treated with docetaxel 75 to 100 mg/m2 intravenously over 1 hour every 3 weeks. Fifty-nine percent of patients had adenocarcinoma and 82% had stage IV disease. At a dose of 100 mg/m2, 30% of evaluable chemotherapy-naive patients (27% of the intent-to-treat population) and 20% of evaluable platinum-refractory/resistant patients (17% of the intent-to-treat population) achieved a partial response; projected median survival is 9 months in both studies. Neutropenia was the primary dose-limiting acute side effect. Fluid retention, which occurred in patients who received multiple courses of treatment, was common but rarely dose-limiting, and may be ameliorated with prophylactic corticosteroids. Other toxic effects were relatively mild. Docetaxel has significant activity against advanced non-small cell lung cancer, producing a major response in both chemotherapy-naive patients and patients who had failed prior platinum-containing chemotherapy.
A new direction for cancer prevention and control is chemoprevention, defined as the use of specific natural and synthetic chemical agents to reverse or suppress carcinogenesis and prevent the development of invasive cancer. The chemopreventive approach depends on the ability of certain chemical agents to block mutagenesis and control cellular differentiation and proliferation in epithelial tissues. Support for the chemopreventive approach is based on the biologic concepts of field cancerization and multistep carcinogenesis, as well as the clinical efficacy already shown by agents such as retinoids and tamoxifen in reversing premalignancy and preventing second primary tumors. Although chemoprevention is not yet established as a standard therapy, the results of reported trials are very promising and have raised tremendous interest in this strategy for cancer prevention. The development of more effective, less toxic chemopreventive agents remains a high priority in furthering the use of this clinically valuable approach to the prevention and control of cancer.
Malignant transformation is often associated with alterations in the expression of normal differentiation markers, which may serve as intermediate end points in carcinogenesis and cancer prevention. To identify early changes in differentiation markers during head and neck cancer development, we examined the expression of cytokeratins (CK1, CK8, CK13, and CK19) and involucrin by immuohistochemical methods in surgical specimens from 29 head and neck squamous cell carcinoma patients that included, in addition to carcinoma, adjacent dysplastic lesions (17 cases), hyperplastic lesions (21 cases), and adjacent histologically normal tissues (15 cases) and in specimens from 31 subjects with premalignant oral lesions (e.g, oral leukoplakia) without cancer, CK13 and involucrin were detected in all specimens from the cancer patients, and no differences in their expression were found among the different histopathological group. CK8 was detected in only 2.7% (1 of 36) of adjacent normal and hyperplastic tissues but in 58.8% (10 of 17) and 75.9% (22 of 29) of dysplastic and carcinoma tissues. The corresponding figures for CK19 expression in adjacent normal, hyperplastic, dysplastic, and carcinoma tissues were 13.3, 70, 71.4, and 82.1%, respectively. The expression of CK1 was not related to the progression from normal to malignant. In the leukoplakia lesions, CK8 CK13, CK19 and involucrin were detected in 13.8, 100, 74.2 and 100% of the specimens, respectively. These results demonstrate that CK19 expression increases in hyperplastic lesions and continues to be expressed in dyplastic and malignant lesions, whereas CK8 expression in low in adjacent normal and hyperplastic tissues and increases only in dysplastic and malignant lesions. Thus, CK19 and CK8 could be markers of sequential premalignant changes in head and neck carcinogenesis.
The cervix is an ideal organ for chemoprevention studies and the study of squamous carcinogenesis. In chemoprevention trial design, four factors are important: high-risk cohorts must be identified; suitable agents must be selected; study designs should include Phase 1, II, and III; and studies should include the use of surrogate endpoint biomarkers. High-risk cohorts can be selected for Phase I, II and III trials in the cervix, for example, patients with high grade lesions such as cervical intraepithelial neoplasia (CIN) grade 3 and carcinoma in situ (CIS). A Phase III trial might also include patients with lesions infected with oncogenic HPV types. The cervix is accessible and can be safely followed with Papanicolaou (Pap) smears and colposcopy. Suitable agents include those likely to work in squamous lesions, including retinoids, difluoromethylornithine, beta-carotene, and others. In Phase I chemopreventive studies, does are de-escalated rather than escalated, determining toxicity and optimal dose schedule. Phase II studies looking at effectiveness need placebo control groups since regression of high-risk lesions is possible. Phase III studies, now multicentric, should be carefully designed and include wide patient representation in order to evaluate the risk-benefit ratio of therapy, focusing on cancer incidence reduction. Surrogate endpoint biomarkers include quantitative histopathology, biologic measures of proliferation, regulation, differentiation, genetic instability, and fluorescence emission. Quantitative histopathologic markers include nuclear grading (i.e., shape, area, optical density, texture), nuclear pleomorphism, ploidy, and nucleolar size and position. Biomarkers under study at the present time in the cervix include proliferation markers (PCNA), regulation marker (EGFR, ras, myc, p53, retinoic acid receptors, ODC, spermidine/spermine ratios), differentiation markers (involucrin, cornifin, keratins), and markers of genetic instability (chromosome polysomy). Fluorescent spectroscopy uses light to probe the biochemical properties of tissue. This technique provides an automated diagnosis in real time with comparable sensitivity and specificity to colposcopy and can be used to monitor lesions in chemoprevention trials. Recruitment designs for cervix studies need to include a large referral population and patients with sufficiently large lesions. Clinicians involved in such studies need to stress contraception and smoking cessation, deal with language barriers, and provide compensation for child care and parking to patients in order to increase compliance.
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BACKGROUND: Second malignant tumors in patients successfully treated for an initial cancer of the upper aerodigestive tract are an important cause of morbidity and mortality. Biologic markers capable of identifying high-risk subgroups of patients who could be targeted for intensive clinical surveillance, therefore, have immense therapeutic and prognostic relevance. We previously demonstrated in a pilot study of 84 patients with cancers of the upper aerodigestive tract that mutagen sensitivity was a significant predictor of risk of developing second malignant tumors. PURPOSE: We extended the study to include 278 patients diagnosed with previously untreated cancers of the upper aerodigestive tract from 1987 to August 1993. METHODS: For each patient, base-line (pretreatment) mutagen sensitivity was measured in vitro in 50 metaphases established from peripheral lymphocyte cultures. Patients with an average of more than 1 chromosomal break/cell were deemed mutagen hypersensitive. Cox proportional hazards analysis was used to predict the risk of developing second malignant tumors associated with mutagen sensitivity. RESULTS: Overall, 44% of the case group exhibited mutagen hypersensitivity. There were no differences in the distribution of mutagen hypersensitivity by site, sex, stage of disease, or smoking status. There were 17 synchronous and 11 metachronous cancers, of which 15 (54%) were smoking-related malignancies. Sixteen (13.1%) of the mutagen-sensitive patients developed second malignant tumors, compared with 12 (7.7%) of the nonsensitive patients. The mean break/cell value (+/- SD) for patients developing second malignant tumors was 1.17 (+/- 0.54), compared with 0.98 (+/- 0.44) for patients with only one cancer (P = .04). Mutagen hypersensitivity conferred a relative risk of 2.67 (95% confidence interval = 1.22-5.79) of developing second malignant tumors. CONCLUSIONS: Mutagen hypersensitivity increases the risk of developing second malignant tumors. IMPLICATIONS: Future research should focus on the molecular mechanisms underlying mutagen sensitivity.
Biomarkers are being sought that could serve as surrogate end points for chemoprevention trials. Micronuclei, cytoplasmic fragments of DNA, have been proposed as a biomarker and studied in oral pre-malignancy. This study evaluated micronuclei frequency in a randomized chemoprevention trial of oral pre-malignancy. A recent clinical trial evaluated the responses of pre-malignant oral lesions to 3 months of therapy with isotretinoin followed by 9 months of either low-dose isotretinoin or beta-carotene. For 57 study participants, micronuclei were counted in mucosal scrapings of the lesion and in normal-appearing mucosa at baseline and following 3 months and 12 months of therapy. Micronuclei counts were higher in scrapings from the lesion than in the normal-appearing mucosa. Following 3 months of isotretinoin, the micronuclei counts in scrapings of the lesion were significantly reduced. With treatment, the mean micronuclei count declined at 3 months. In a randomized comparison, both isotretinoin and beta-carotene maintained the suppression of micronuclei. The change in micronuclei count was not associated with the clinical or histological response to treatment. Chemoprevention treatment with isotretinoin led to a reduction in frequency of micronuclei, a marker of recent DNA injury, which was then maintained by both isotretinoin and beta-carotene.