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Biomedical subjects

G B Snow

Publications and source records attributed to G B Snow.

At least 163 records · Page 9Linked to original sources
PubMed1993

Modern imaging techniques and ultrasound-guided aspiration cytology for the assessment of neck node metastases: a prospective comparative study.

Although palpation has proved to be an unreliable staging procedure, the indications for and the implications of more reliable radiologic staging methods for the neck in patients with a primary squamous cell carcinoma of the head and neck remain controversial. Only a very accurate imaging technique can replace neck dissection in clinical NO disease. This study compares the value of palpation with computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound (US) with or without guided aspiration cytology for neck node staging. One hundred and thirty-two patients with squamous cell carcinoma of the head and neck were examined radiologically before undergoing a total of 180 neck dissections as part of their treatment. CT, US and MRI proved to be significantly more accurate than palpation for cervical lymph node staging. The accuracy of US-guided aspiration cytology was significantly better than of any other technique used in this study. Modern imaging techniques are essential for appropriate assessment of neck node metastases. In view of advances in the accuracy of contemporary imaging, the need for elective treatment of the neck requires reappraisal.

Biopsy, Needle↗
PubMed1993

The value of twice yearly bronchoscopy in the work-up and follow-up of patients with laryngeal cancer.

The aim of this retrospective study was to investigate the usefulness and feasibility of twice-yearly bronchoscopy and sputum cytology in patients with laryngeal cancer. In 170 selected patients, 500 (both initial and during follow-up) bronchoscopies were performed. There was a maximum follow-up of 34 months. 5 (2.8%) male patients developed lung cancer. In only 2 of them was the diagnosis based on bronchoscopy alone. After treatment with curative intent, both patients developed a recurrent lung carcinoma. According to most patients' experience, regular bronchoscopy is unpleasant. It is concluded that twice-yearly bronchoscopy and sputum cytology in patients with laryngeal cancer is not useful as a routine procedure. At present, chemoprevention of second primary tumours seems the most promising adjunctive treatment modality.

Adult↗
PubMed1993

Squamous cell carcinoma of the lip and oral cavity in The Netherlands; an epidemiological study of 740 patients.

The epidemiological data of 740 patients with primary squamous cell carcinoma (SCC) of the lips or oral cavity is reported. The mean age was 63 years. The mean onset of oral cancer in women was 7 years later than in men. Patients under the age of 40 years were mainly males. The male-to-female ratio ranged from 8.3 for the lower lip to 0.9 for the upper alveolar ridge with an overall ratio of 1.8. In the case of multiple oral SCCs the tongue was the most frequently affected site. No significant association was found between the age or gender of patients and the size of the tumour. However, a significant association was observed between the site and size of the tumour. Lesions of the lower lip had a significantly smaller size than tumours of other sites. Furthermore, a linear trend could be observed between the size of the tumour and the clinical stage of the neck.

Adult↗
PubMed1993

Epirubicin in patients with advanced or recurrent adenoid cystic carcinoma of the head and neck: a phase II study of the EORTC Head and Neck Cancer Cooperative Group.

BACKGROUND: Because of the rarity of salivary gland cancer, little is known about the single-agent activity of most anticancer agents in the different histologic types of these cancers. PATIENTS AND METHODS: Twenty patients with advanced or recurrent adenoid cystic carcinoma of the head and neck were treated with epirubicin on a low-dose weekly schedule (30 mg/m2/week) for eight weeks and, in instances of no response, a high-dose three-weekly schedule (> or = 90 mg/m2). Thirteen patients had locoregional disease (12 recurrences), seven of them also had distant metastases and seven had distant metastases only. All had documented progressive disease, and 17 were symptomatic. RESULTS: Two objective responses of 7.5 and 20 months were observed in patients with locally recurrent disease, and ten patients showed disease stabilization. The median time to progression was 16 weeks (range 2-250 weeks) and the median survival 67 weeks (range 13-272+ weeks), with three patients still alive more than five years after the initiation of chemotherapy. Contrary to the rather modest objective response rate, symptomatic improvement occurred more frequently (29.4%) and was evident within 8 weeks of treatment. CONCLUSIONS: This type of chemotherapy should be reserved for patients with rapidly progressive disease or those with symptomatic disease.

Adult↗
PubMed1993

Retroviral p15E-related serum factors and recurrence of head and neck cancer.

Surgical removal of head and neck squamous cell carcinoma (HNSCC) restores the defective monocyte polarization found in patients with HNSCC. Since HNSCC contain p15E-like low molecular weight factors < 25 kD (LMWF) capable of suppressing N-formyl-methionyl-leucylphenylalanine (fMLP)-induced monocyte polarization, it is likely that HNSCC removal eradicates the production site of p15E-like factors. This report describes a prospective follow-up study on the levels of bioactive p15E-like serum factors for a period of 2 years in nine patients with HNSCC who had no recurrence and 11 patients with HNSCC who showed residual or recurrent disease after treatment. In the group of patients without recurrent disease p15E-like bioactivity gradually decreased and eventually became negative. In patients with recurrent/residual disease p15E-like bioactivity remained high or even became positive before or at the time of diagnosing tumour recurrence. This study strongly supports the concept that HNSCC tumours are the production site of p15E-like immuno-suppressive factors and indicates that serum p15E-like factors may be used for future studies on early serum markers for recurrent/residual disease developing in the first year after treatment.

Aged↗
PubMed1993

Tobacco and alcohol related to the anatomical site of oral squamous cell carcinoma.

The aim of the present study was to evaluate the possible relationship between tobacco smoking and alcohol drinking and the anatomical sites of squamous cell carcinoma (SCC) of the lip and oral cavity. For this purpose, a case-case study has been performed in 690 patients. The study was focused on the relative risk (RR) or developing SCC at various (sub)sites, for smokers and drinkers of alcohol (divided into moderate and heavy users) relative to non-smokers and non-drinkers. Estimates of ratios of these relative risks were obtained. The relative risk associated with tobacco smoking, adjusted for the use of alcohol, appeared to be highest for SCC in the retromolar area, followed by the floor of mouth, whereas the lowest RR was found in the cheek mucosa. For alcohol drinking, adjusted for tobacco smoking, RR of SCC of the floor of mouth was significantly higher than for the tongue, whereas the RR of SCC of the cheek appeared to be lowest. Furthermore, this study suggests that the contrasts between relative risks, observed by anatomical site of oral SCC, are more pronounced for tobacco smoking than for the use of alcohol. The possible local and systemic factors responsible for these variations of susceptibility for tobacco and alcohol within the oral cavity are discussed.

Aged↗
PubMed1993

Labeling of monoclonal antibodies with rhenium-186 using the MAG3 chelate for radioimmunotherapy of cancer: a technical protocol.

A detailed technical protocol is provided for reproducible and aseptical production of stable 186Re-monoclonal antibody conjugates. Labeled Mab E48 IgG and its F(ab')2 fragment which are promising candidates for radioimmunotherapy of squamous cell carcinoma of the head and neck were used for evaluation. S-benzoylmercaptoacetyltriglycine (S-benzoyl-MAG3) was used as a precursor. Rhenium-186-MAG3 was prepared via a unique solid-phase synthesis, after which known strategies for esterification and conjugation to Mab IgG/F(ab')2 were applied. The biodistribution of 186Re-E48 F(ab')2 in tumor-bearing nude mice was found to be comparable to that of analogously labeled 99mTc-E48 F(ab')2 or 131I-E48 F(ab')2, indicating that the intrinsic behavior of the antibody remains preserved when using this labeling technique. Radiolytic decomposition of 186Re-E48 IgG/F(ab')2 solutions of 10 mCi.ml-1 was effectively reduced by the antioxidant ascorbic acid. Upon increase of the Re-MAG3 molar amount, a conjugation of seven to eight Re-MAG3 molecules per Mab molecule was generally the maximum ratio that could chemically be obtained. Such a ratio did not impair the immunoreactivity or alter the in vivo biodistribution characteristics of the immunoconjugate, making this labeling procedure suitable for general clinical application.

Animals↗
PubMed1992

Prevalence and expression of human papillomavirus in tonsillar carcinomas, indicating a possible viral etiology.

The presence of human papillomavirus (HPV) DNA was assessed in biopsies of tonsillar carcinomas (n = 10) and cases of tonsillitis (n = 7), serving as controls, by general-primer-mediated PCR (GP-PCR). All carcinomas appeared HPV-positive, whereas all cases of tonsillitis were HPV-negative. Additional type-specific PCR for HPV 6, 11, 16, 18, 31 and 33 revealed that 4 carcinomas contained HPV 16 DNA, 4 contained HPV 33 DNA and 1 contained an HPV 16/33 double infection. False positivity was excluded by additional Southern blot analysis of type-specific PCR-positive samples (n = 4). Further characterization of GP-PCR products by sequence analysis revealed that 2 carcinomas contained still uncharacterized HPV genotypes; one of these also contained HPV 33 DNA and one was negative by type-specific PCR. Application of RNA PCR revealed expression of HPV 16 or HPV 33 E7 encoding spliced E6*1 transcripts in all tonsillar carcinomas (n = 4) examined. Additional non-radioactive RNA in situ hybridization performed on 3 biopsies revealed the presence of HPV 16 or HPV 33 E7 transcripts exclusively localized within the carcinoma cells, whereas stroma stained negative. These findings strongly support a role for certain HPV types in the pathogenesis of tonsillar carcinomas.

Amino Acid Sequence↗
PubMed1992

[Otitis media with effusion as initial symptom of a parapharyngeal tumor].

Two patients are described who had unilateral otitis media with effusion (OME) as the first and only symptom of a parapharyngeal tumour. The first patient, a 77-year-old woman, was operated 14 months after the onset of the OME. A polymorphous adenocarcinoma was resected from the left parapharyngeal space. In the second patient, a 59-year-old man, the diagnosis was established 7 months after the first symptom. A pleomorphic adenoma was removed surgically from the right parapharyngeal space. In case of a persistent unilateral OME in an adult, a parapharyngeal tumour should be considered as one of the possible causes.

Adenocarcinoma↗
PubMed1992

Expression and characterization of two differentiation antigens in human stratified squamous epithelia and carcinomas.

Using viable cells of a human squamous-cell carcinoma (SCC) cell line as immunogen, we generated 2 monoclonal antibodies, MAbs K984 and K928, to SCC surface antigens. Immunoperoxidase staining of frozen sections of normal epidermis revealed that MAb K984 reacts with the poorly differentiated basal cells, while MAb K928 is reactive with the more highly differentiated suprabasal cells. A similar complementary reaction pattern of these antibodies was demonstrated in the majority of well-differentiated human tumors and some moderately differentiated SCCs. In contrast, simultaneous reactivity of MAb K984 and K928 was found for the majority of cells within other well- and moderately differentiated SCCs, as well as all poorly differentiated SCCs. Further biochemical characterization indicated that the antigen recognized by MAb K984 is similar to the one recognized by MAb SF-25. MAb K928 recognizes a 50- to 55-kDa molecule under non-reducing conditions. Antibodies with similar features to MAb K928 have not been described previously. The antigens recognized by MAbs K984 and K928 can be regarded as novel markers associated with cellular maturation in squamous epithelia. The antigen detected by MAb K984 is probably associated with the proliferating fraction in SCCs.

Antibodies, Monoclonal↗
PubMed1992

[Neck lymph node dissection in squamous cell carcinoma originating in the head-and-neck area; the significance for the prognosis].

Neck dissection has a therapeutical as well as a prognostic relevance with respect to regional recurrence and distant metastases. Between January 1973 and July 1986 576 neck dissections in 511 patients (396 men, 115 women, among whom 486 with squamous cell carcinoma of the head and neck, and 14 with neck metastases of an unknown primary tumour) were performed at the department of Otolaryngology-Head and Neck Surgery of the Free University Hospital, Amsterdam. Patients with tumour at the margins were excluded. Recurrence-free curves were calculated according to Kaplan-Meier and the log rank test was used to test the differences. All patients underwent a comprehensive neck dissection and were irradiated postoperatively when three or more tumour-positive nodes or extranodal spread were reported by the pathologist. Endpoint for analysis was occurrence of an ipsilateral neck recurrence or of a distant metastasis. Figures were corrected for a simultaneous recurrence at a higher level. A total of 29 neck recurrences (7.2%; n = 523) and 26 distant metastases (10.7%; n = 281) were demonstrated in the 5-year follow-up period. The number of positive nodes was of prognostic significance for both events (p = 0.039 and p = 0.0027). Extranodal spread was shown only to increase the incidence of distant metastases (p = 0.017), whereas its prognostic value with regard to recurrence in the neck was nullified by the strict institution of postoperative radiotherapy. It is recommended to give radiotherapy to patients with two positive nodes and possibly to every patient with a histopathologically positive neck.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Autoantibodies against constituents of neutrophils in the diagnosis and treatment of (isolated) subglottic stenosis.

Six patients had a subglottic stenosis either as a presenting symptom or as a manifestation of a systemic disease. All patients had in common the presence of circulating autoantibodies against constituents of neutrophils on indirect immunofluorescence. Cytoplasmic and perinuclear staining patterns were recognized. Such autoantibodies have been reported in Wegener's granulomatosis, microscopic polyarteritis, (idiopathic) glomerulonephritis, and Churg-Strauss syndrome. However, only one of the six patients fulfilled the criteria for these conditions. Because a positive test for autoantibodies against constituents of neutrophils is rare in other conditions and because other diseases had been excluded, we suggest that this places subglottic stenosis within the spectrum of necrotizing (granulomatous) vasculitis. The consequences for therapy are discussed.

Adolescent↗
PubMed1992

Management of cervical lymph nodes in patients with head and neck cancer.

The status of the cervical lymph nodes is the single most important prognostic factor in head and neck cancer. Unfortunately, clinical assessment of the neck is not very accurate, although newer imaging techniques such as CT, MRI and ultrasound-guided fine needle aspiration cytology can be used to improve upon the results of clinical palpation alone. While diagnostic techniques remain less than 100% accurate, the risk of occult disease in the neck will remain. If this occurrence is judged to be greater than 15-20%, elective treatment to the neck may then be justified. When the neck is treated surgically, histological information can be gained which has both prognostic and therapeutic implications. Indications for the use of surgery and radiotherapy for the elective and therapeutic management of the neck and the results of such treatment are discussed.

Combined Modality Therapy↗
PubMed1992

Micrometastases from squamous cell carcinoma in neck dissection specimens.

The incidence of micrometastases in cervical lymph nodes from squamous cell carcinomas of the head and neck was studied using routine histopathological examination. Micrometastases were found in 66 lymph nodes in 41 of the 92 tumor-positive neck dissection specimens. The detection of these micrometastases influenced postoperative treatment in 3 of the 77 patients with neck node metastases. The value of additional sectioning for detecting micrometastases was thus assessed. Sectioning at a deeper level in 600 originally histopathologically negative lymph nodes from 64 patients revealed 7 additional micrometastases in 5 patients. Antikeratin staining with a mixture of two monoclonal antibodies (AE1 and AE3) revealed 4 micrometastases in 739 originally histopathologically negative lymph nodes in 3 of 13 patients studied. Because of the unknown prognostic significance of micrometastases and the consequent arbitrary consequences for postoperative treatment, present findings show that the extra workload of immunostaining and deeper sectioning does not warrant their routine use in clinical practise.

Carcinoma, Squamous Cell↗
PubMed1992

Potential for targeting head and neck squamous cell carcinoma with monoclonal antibody K984.

In previous reports we have described the development of mAb K984, reactive with an epitope expressed on the outer cell surface of undifferentiated, proliferating cells in normal stratified squamous epithelia and their neoplastic counterparts. The K984 antigen was also found to be homogeneously expressed by in vitro cultured squamous cell carcinoma (SCC) cell lines. In the present study we demonstrate that mAb K984 induces a significant, dose-dependent growth inhibition when SCC cells are grown in vitro as monolayer cultures in the presence of mAb K984. These data seem to indicate that mAb K984 has potential for tumour targeting, especially in a therapeutic setting. As a first approach to evaluate the suitability of mAb K984 for tumour targeting in vivo, radiolabelled mAb K984 was administered to SCC-xenografted nude mice. Selective tumour accumulation of mAb K984 was observed. Tumour to blood ratios and tumour to non-tumour ratios, as based on the biodistribution data, were at least ten times higher in case of the specific mAb K984 when compared to another non-specific, isotype-matched control antibody. mAb K984 was also capable of visualizing tumour deposits in xenografted nude mice. The corollary of these findings is that the mAb K984-defined antigen probably is involved in the regulation of proliferation of stratified squamous epithelium and squamous cell carcinoma and that mAb K984 has potential for specific tumour targeting.

Animals↗
PubMed1992

Delay in diagnosis of oral squamous cell carcinoma; a report from The Netherlands.

The referral pattern, patients' and doctors' delay of a limited number of 50 patients suffering from oral squamous cell carcinoma have been investigated. The majority of the patients consulted the family doctor as the first source of help. The mean patients' and doctors' delay was 103 and 22 days, respectively the median being 35 and 11 days, respectively. The gender, dental status, site and tumour size did not show a significant correlation with the delay. Measures directed to the early detection of oral cancer should place special emphasis on the patients' delay.

Attitude to Health↗