Biomedical subjects

C A Meeuwis

Publications and source records attributed to C A Meeuwis.

33 records · Page 2Linked to original sources

PubMed1995

Radiation therapy for cancer of the piriform sinus. A failure analysis.

This paper analyzes the results of 109 piriform sinus (PS) cancers treated between 1973 and 1984 by surgery and/or external beam radiation therapy (EBRT) in a large comprehensive cancer center, and in particular tries to redefine the role of EBRT in the management of these tumors. At the time the policy was to start with EBRT to a dose of 40 Gy. A good response to a first series was to be continued by EBRT (RT-1); in case of poor responding tumors, the primary and neck were to be operated upon (RT-S). Poor responders unfit for S or those refusing S were also carried to a full course of EBRT (RT-2). The RT-S, RT-1, and RT-2 actuarial 5-year locoregional relapse-free survival (LR-RFS) and overall survival (OS) were 60%, 40%, and 20% and 40%, 30%, and 20%, respectively. In a multivariate Cox regression analysis the most important prognostic factor appeared to be N-stage, with hazard ratios of 1.16 (N1), 2.2 (N2), and 3.3 (N3). The RT-S treatment group fared best (hazard ratio 0.5). The risk of relapse for T3,4 was 1.3 times as high as opposed to T1,2. For stage I/II (19/21 treated by EBRT only), a LR-RFS and OS at 5 years of 60% and 40%, respectively, was observed. This analysis supports data for stage III/IV PS cancers to be treated by surgery combined with EBRT; in stage I/II there might be a role for EBRT alone. It is speculated that with further sophistication in RT-techniques, the locoregional control rates by EBRT alone could improve.

Adult↗

PubMed1995

Radiation-induced fibrosarcoma of the tongue.

Three patients with a radiation-induced fibrosarcoma of the tongue are presented. All three patients had interstitial radiotherapy and tumour-induction by irradiation seems to be the most likely explanation for the tumour in these patients.

Aged↗

PubMed1995

Heat and moisture exchangers as a treatment option in the post-operative rehabilitation of laryngectomized patients.

A multi-institutional, prospective clinical study was undertaken to investigate whether the use of a heat and moisture exchanger (HME) in the period following total laryngectomy could prevent the development or reduce the severity of respiratory symptoms. Fifty-nine patients from three hospitals were provided with HMEs, either immediately post-surgery or, in the case of post-surgical radiotherapy, upon completion of the radiotherapy. For the total sample (n = 59) statistically significant improvements over time (between 3 and 6 months) could be found in forced expectoration (P < 0.05), in the perceived voice quality (P < 0.001), social anxiety (P < 0.001), social interactions (P < 0.001) and in feelings of anxiety and depression (P < 0.05). Repeated measures analysis of variance indicated statistically significant group differences over time in forced expectoration and stoma cleaning (P < 0.05). No statistically significant differences over time were noted between the regular and non(regular) HME user groups in voice quality or in various aspects of daily living.

Humans↗

PubMed1995

Patient participation in clinical decision-making for treatment of T3 laryngeal cancer: a comparison of state and process utilities.

PURPOSE: To study the use of two different approaches, and feasibility of four commonly used utility assessment methods to assess preferences for treatment of T3-laryngeal cancer by surgery or radiation therapy (RT). METHODS: Utility assessment methods, namely, time trade-off (TTO), standard reference gamble (SRG), rating scale (RS), and direct comparison (DC), were used to assess utilities in two groups of former cancer patients (n = 10 for both), a group of clinicians (n = 9), and a group from the general population (n = 10). For the treatment modalities, ie, surgery and RT, two types of scenarios were developed and used: the state scenario, which describes a stable health state after treatment, and the process scenario, which describes a dynamic process. First, utilities were assessed based on state scenarios. Next, respondents were thoroughly informed and educated with respect to the relevant aspects of both treatment modalities. Subsequently, utilities were again assessed, but now based on the process scenarios. The outcome of each approach was calculated and expressed in a quality-adjusted life-expectancy (QALE) score for each treatment modality, and the treatment with the highest outcome was said to be the preferred treatment modality. RESULTS: In general, a higher QALE score for each treatment modality was found for clinicians and for the general population as compared with the former-cancer-patient groups. When the outcome of both approaches was compared on an individual level dependent on the utility assessment method, 32% to 43% of respondents showed an inconsistent treatment preference. CONCLUSION: The approach to assess utilities and the extent to which respondents are informed about treatment modalities have a major effect on individual treatment preferences.

Aged↗

PubMed1994

Macrophage and dendritic cell infiltration in head and neck squamous-cell carcinoma; an immunohistochemical study.

A study was undertaken to help us reach a better understanding of the tumor-infiltrating pattern of lymphoid cells and in particular of monocyte-derived cells, namely the CD68+, acid-phosphatase-expressing scavenger macrophages and the MHC-class-II- and S100-antigen-presenting dendritic cells in head and neck squamous-cell carcinoma. In the stroma of the tumors distinctive small fields of lymphocytes were found, the T cell areas of these fields being intermingled with dendritic cells. Intra-epithelial dendritic cell infiltration was low. The infiltrative pattern of macrophages was similar to patterns described in earlier studies with substantial stromal invasion and inconsistent intra-epithelial invasion, but small granuloma-like structures of CD68+ macrophage-like cells, found in the stroma of tumors, have not been reported before. The histochemical localization of the tumor-infiltrated dendritic cells and macrophages supports the view that the former cells are involved in the sensitization to tumor antigens, whereas the latter cells are involved in tumor cytotoxicity/scavenging of tumor cell debris. Although it has been shown in the past that transmembranal (TM) factors (p15E-like factors) present in the serum and tumor of patients with cancer of the head and neck have suppressive effects on monocyte/macrophage/dendritic cell function, a relationship between the intensity of epithelial staining for TM factors and the infiltrative pattern of monocytes/macrophages/dendritic cells could not be demonstrated.

Antigens, CD↗

PubMed1992

Reirradiation of recurrent head and neck cancers: external and/or interstitial radiation therapy.

Recurrent cancer in the head and neck is not an uncommon clinical problem. The average cure rate of these patients has been reported to vary between 30 and 40% and most failures are due to locoregional relapses. After a previous full course of radiation, surgery is the salvage modality of choice; however, if surgery was not feasible for whatever reason, reirradiation has been offered to some patients. To establish the role of reirradiation in head and neck cancer, we analyzed a 13-year experience with patients reirradiated in the DDHCC. The reirradiation was performed between 1970 and 1980 by means of external beam radiation therapy (ERT series; n = 55) and between 1985 and 1988 by external radiation combined with interstitial radiation therapy (IRT +/- ERT series; n = 18). A minimum follow-up of 3 years was allowed for. An improvement in local control was observed (50% vs. 29%) for the IRT +/- ERT series and the ERT series, respectively. The improvement in local control was not reflected in a survival benefit; i.e. an actuarial overall survival of 20% at 5 years was observed in both series. No treatment-related deaths occurred. However, for the patients that were controlled at the reirradiated site, 28% (4/16 of the ERT series and 3/9 of the IRT +/- ERT series) did experience severe side effects.

Brachytherapy↗

PubMed1992

Carotid sinus syndrome after carotid artery surgery.

A 63 year old woman had been intensively treated for recurrent carcinoma of the neck. Following acute vascular surgery of the carotid artery, she developed the vasodilatory type of the carotid sinus syndrome. The presentation of this type of the syndrome was remarkable, since it is usually associated with primary or metastatic carcinoma in the neck region. Previous cancer treatment may have modified the course of disease in this patient, which ultimately had a lethal outcome.

Carotid Arteries↗

PubMed1991

Histologic evaluation of crushed cartilage grafts in the growing nasal septum of young rabbits.

The evolution of crushed cartilage grafts in a growing nasal septum of young rabbits was histologically investigated. Crushing leads to necrosis of the greater part of the graft. The characteristic distribution of surviving cells in isolated areas at the surface of the graft reflects different mechanical properties of the centrally and peripherally located cartilage. The necrotic parts are eliminated and replaced by new cartilage formed by surviving chondrocytes or perichondrium. The result is a complex structure composed of two types of cartilage and of fibrous tissue without any distinct organization, but nevertheless capable of growth. However, it lacks strength to transform growth into adequate lengthening of the septum. Subsequently, this will lead to the development of multiple deviations. It is concluded that crushed cartilage is no suitable implant for the reconstruction of parts of the septum which are essential in supporting the outgrowth of the nose.

Animals↗

PubMed1991

Wound healing of autologous implants in the nasal septal cartilage.

The cartilaginous nasal septum of the child is often involved in trauma or congenital deformation. In perspective of its role in postnatal growth of the midface, the wound healing of septal cartilage in reaction to various surgical procedures was studied in young rabbits. It was concluded that (1) elevation of mucoperichondrium does not induce significant histologic reactions in the septal cartilage and (2) the wound reaction of cut edges includes only a +/- 0.8-mm-deep zone and lasts no longer than 2 weeks, resulting in a stump, encapsulated by fibrous tissue. Reconnection of separated parts occurs 2 weeks after surgery, mostly by merging of the perichondrial layers. Reimplantation of resected cartilage does not lead to normalisation of septal growth. This is not caused by extensive necrosis, loss of morphological organisation or decreased growth potential of the reimplanted cartilage. The essential factor seems to be dislocation (duplication, angulation) of the implant versus the non-mobilised parts of the septum preventing the growth of the implant to contribute fully to the lengthening of the total septum.

Animals↗

PubMed1990

Wound healing of the nasal septal perichondrium in young rabbits.

The effects of elevation of the perichondrium of the nasal septum, whether or not followed by resection of the cartilage, was histologically studied in young rabbits. The perichondrium has proved to be a highly reactive tissue. The degree of reaction varied from a transient oedema to the production of large quantities of cells, differentiating into new cartilage. The type of reaction appeared to depend on the conditions at the inner surface of the elevated perichondrium. The new cartilage differs from the original septal cartilage in morphology and growth potential. The data described above can contribute to the interpretation of previous observations in children.

Animals↗

PubMed1989

Evaluation of treatment results of squamous cell carcinoma of the buccal mucosa.

Of the 49 patients with squamous cell carcinoma of the buccal mucosa referred to the Rotterdam Radio-Therapeutic Institute (RRTI) and Universital Hospital Dijkzigt Rotterdam (AZD) during 1970-1984, 31 patients had an advanced stage of disease, 21 patients had clinical evidence of lymph node metastasis. Forty patients were treated with curative intention. Treatment modalities were: radiation therapy, preoperative radiation followed by surgery, and primary surgery. Eighteen of the 40 patients (45%) developed a local tumor recurrence; nearly all recurrences occurred within 2 years. The incidence was equal in all treatment groups. Of the 22 patients with initial clinically negative neck, regional relapse occurred in 3 of the 14 patients, of whom the neck was not treated electively by radiation therapy; all three in combination with a local recurrence. None of the 8 patients with electively irradiated necks developed a regional relapse. Eight of the 18 patients with initial clinically enlarged lymph nodes treated either by radiotherapy or surgery, developed a regional relapse, 5 in combination with a local recurrence. Treatment of the clinically positive neck by neck dissection was superior to radiotherapy. Local recurrence carried a poor prognosis. Almost 70% died of their disease. The overall and corrected 5-year survival was 38% and 52% respectively.

Carcinoma, Squamous Cell↗

PubMedDate not supplied

First results with the Blom-Singer adjustable tracheostoma valve.

The Blom-Singer adjustable tracheostoma valve (ATV) is a new tracheostoma valve, introduced in 1992 to improve voice rehabilitation after total laryngectomy. Little research has been done to evaluate the benefits of this valve. Our study evaluates the advantages and disadvantages of using this device. Eighteen laryngectomized patients with a low-resistance Provox voice prosthesis received an ATV, using minimal selection criteria. The patients are evaluated according to a specific protocol. The effectiveness of the humidifilter, valve and fixation method and the benefits are evaluated. Approximately 66% of the 18 patients are still using the ATV. We report the differences between the current users and the dropout group. Patient factors are discussed that seem to have an impact on the effective use of the valve, such as age and mucus production. We consider the ATV to be a valuable device for fingerless speech in the laryngectomized patient.

Adult↗

PubMedDate not supplied

Three-dimensional models of the tracheostoma using stereolithography.

The availability of an accurate three-dimensional (3-D) model of the tracheostoma and trachea of the laryngectomy patient would be of great help in prototyping of endotracheal prostheses. Stereolithography has been described for skull and jaw models but never for soft-tissue reconstructions of the trachea. CT was performed on tracheostomas of 8 patients. The CT data were used to make 3-D models by means of stereolithography. Inverted CT data were used to create air contour models of the same tracheostomas. Eight soft-tissue and 8 air contour models were reconstructed from CT data, showing accuracy and great detail. In this paper we present a previously unreported application of the stereolithography technique. Measurements and prosthesis prototyping, which are impossible to perform on tracheostomas in patients, can now be executed safely. We are using the 3-D tracheostoma models in our research project to develop an endotracheal fixation method for tracheostomal valves.

Humans↗

PubMedDate not supplied

The use of confidence intervals for individual utilities: limits to formal decision analysis for treatment choice.

This paper discusses the use of confidence intervals for utility measurements. Classic test theory is applied to estimate confidence intervals for utilities. The theory is enhanced to calculate confidence areas for combined utilities and confidence bands for the threshold line. As an example it is shown that, if confidence intervals are taken into account, the implied preferred treatment of T3-larynx carcinoma patients is uncertain for a wide range of utilities, considering the mediocre reliability of most methods of utility assessment. This implies that although utility measurement and formal decision analysis can be a useful way to look at the decision problem, ambiguity, which must be resolved by other means, will often remain.

Aged↗

PubMedDate not supplied

Stress and woundhealing of the cartilaginous nasal septum.

In the cartilaginous nasal septum of growing rabbits a stress is demonstrated, released by an incision perpendicular to the antero-posterior axis and rebuilt within a period of 3 weeks when the mechanical continuity of the septum is restored. The latter is the result of a process of woundhealing establishing a firm perichondrial side-to-side connection between the stumps.

Animals↗