Arlen D. Meyers

Photodynamic therapy for treatment of solid tumors--potential and technical challenges.

Photodynamic therapy (PDT) involves the administration of photosensitizer followed by local illumination with visible light of specific wavelength(s). In the presence of oxygen molecules, the light illumination of photosensitizer can lead to a series of photochemical reactions and consequently the generation of cytotoxic species. The quantity and location of PDT-induced cytotoxic species determine the nature and consequence of PDT. Much progress has been seen in both basic research and clinical application in recent years. Although the majority of approved PDT clinical protocols have primarily been used for the treatment of superficial lesions of both malignant and non-malignant diseases, interstitial PDT for the ablation of deep-seated solid tumors are now being investigated worldwide. The complexity of the geometry and non-homogeneity of solid tumor pose a great challenge on the implementation of minimally invasive interstitial PDT and the estimation of PDT dosimetry. This review will discuss the recent progress and technical challenges of various forms of interstitial PDT for the treatment of parenchymal and/or stromal tissues of solid tumors.

Dysphagia following head and neck cancer surgery

Surgical resection of head and neck cancer results in predictable patterns of dysphagia and aspiration due to disruption of the anatomic structures of swallowing. Common procedures undertaken in the treatment of head and neck cancer include tracheostomy, glossectomy, mandibulectomy, surgery on the palate, total and partial laryngectomy, reconstruction of the pharynx and cervical esophagus, and surgery of the skull base. An overview is presented of normal swallowing physiology, as well as swallowing perturbations that are frequently encountered in postoperative head and neck cancer patients.

Complications of CO2 Laser Surgery of the Larynx

Since the introduction of CO2 laser surgery, surgeons have stressed the importance of protecting nontarget structures from errant irradiation. Although striking areas outside the intended field may inflict little or no damage, irradiating an exposed endotracheal tube may result in an endotracheal fire. Recent experience with a case of endotracheal tube ignition led to a reevaluation of those factors associated with this serious complication. In an attempt to determine the best endotracheal tube to use during laser surgery of the larynx, the flammability of polyvinyl chloride and red rubber endotracheal tubes was compared. Several factors were noted to contribute to the potential hazard of endotracheal tube ignition. Since red rubber tubes are less flammable, they should be used during laryngeal CO2 laser surgery.

AUTOLOGOUS FAT INJECTION FOR VOCAL CORD MEDIALIZATION IN THE CANINE LARYNX

This study examined the use of autologous fat as an alternative to Teflon and collagen as the implantable material in vocal cord medialization. Five animals underwent left recurrent laryngeal nerve sections with subsequent fat harvest and implantation into the left true vocal cords. Three animals were killed after 48 hours and 2 after 3 weeks; their larynges were examined with light microscopy. The results of the 48-hour samples show mode-rate acute inflammation and few areas of focal necrosis. The 3-week samples show no necrotic foci, minimal foreign-body reaction, and maintenance of structure and volume of the injected fat. Autologous fat may prove to be a valuable alternative to nonautologous injectable material in vocal cord augmentation.

Preliminary evaluation of selected acoustic and glottographic measures for clinical phonatory function analysis

Summary Acoustic and glottographic measures may provide important information that could enhance clinical management and documentation of vocal dysfunction. Acoustic measures such as jitter and shimmer reflect “short-term” perturbations, or instabilities of the voice, and the coefficients of variation for frequency and for amplitude reflect “long-term” perturbations. Interpretations of these acoustic measures are based on the assumption that vocal perturbations may be related to laryngeal tissue abnormalities, asymmetries in vocal fold movement, or neuromuscular fluctuations in the respiratory, laryngeal, or vocal tract systems. The abduction quotient is a glottographic measure related to laryngeal adduction and is obtained from an analysis of the electroglottograph signal. The adduction measure appears to be independent of the acoustic perturbation measures. Interpretations of the acoustic and adductory measures may, therefore, complement each other for greater understanding of a patients laryngeal behavior. Visual displays of the acoustic and glottographic signals also are discussed to demonstrate their value in voice signal interpretations. Case studies illustrate potential interpretations of the acoustic perturbation and abduction quotient measures.

The intraoperative management of the thyroid gland during laryngectomy

The standard of care of laryngeal cancer surgery is wide field excision of the larynx combined with ipsilateral thyroid lobectomy. A retrospective review of 247 laryngectomies performed between 1979 and 1989 was undertaken to determine specific intraoperative indications for thyroid gland removal. The incidence of thyroid disease in our patients with laryngeal cancer was compared to the normal population. Eight percent of thyroid specimens removed during laryngeal cancer surgery demonstrated invasion by squamous cell carcinoma. All patients having thyroid invasion had T3 or T4 laryngeal lesions that were stage IV at the time of surgery. All these lesions were found to have transglottic growth and laryngeal cartilage invasion by the pathologist. All of these patients also had abnormal thyroid glands intra‐operatively and laryngeal cartilage destruction that was evident intraoperatively. Total thyroidectomy with bilateral paratracheal and pretracheal lymph node dissection is indicated when squamous cell carcinoma of the larynx involves the thyroid gland. Prophylactic ipsilateral thyroid lobectomy and isth‐musectomy is warranted for large laryngeal cancers (T3, T4) that involve the anterior commissure, the subglottic area, or extend transglottically. Routine thyroid gland removal is not indicated for the majority of laryngeal cancers that do not meet the aforementioned criteria. Finally, abnormal thyroid histopathology was diagnosed in 37% of the surgical thyroid gland specimens removed during laryngectomy.

Myxoinflammatory fibroblastic sarcoma of the neck

Background:  Myxoinflammatory fibroblastic sarcoma (MIFS), also named inflammatory myxohyaline tumor of distal extremities with virocyte or Reed‐Sternberg cells, is a rare tumor typically presenting as a painless mass in the extremities.

Identification of individuals at high risk for head and neck carcinogenesis using chromosome aneuploidy detected by fluorescence in situ hybridization

To visualize the accumulation of chromosome abnormalities in head and neck squamous cell carcinomas (HNSCC) and investigate the extension of the abnormal field, we applied the fluorescence in situ hybridization (FISH) technique to tumor cells and cells collected from a large extension of clinically normal buccal mucosa distant from the tumor in 10 patients. DNA probes specific for 14 human chromosomes (1, 2, 3, 6, 7, 8, 9, 10, 11, 12, 15, 17, X, and Y) were used in dual-target, dual-color FISH assays. Control specimens were collected from oral mucosa of 10 healthy non-smokers, in order to define the tolerance limits for abnormalities, and from 10 healthy smokers. Extensive aneuploidy was detected in most of tumor specimens, more frequently represented by chromosome gains than losses. Interestingly, the clinically normal distant oral regions displayed chromosomal aneuploidies in seven out of the 10 patients tested. These findings support the occurrence of field cancerization in HNSCC. In addition, interphase FISH is demonstrated as an effective technique for detecting chromosome aneuploidy associated with malignancy and a potential tool for non-invasive screening of individuals at high-risk for HNSCC.

Chromosomal Aneuploidy Precedes Morphological Changes and Supports Multifocality in Head and Neck Lesions

Objective To identify chromosome changes associated with the transformation of dysplastic lesions and to verify evidence for multifocality in synchronous premalignant lesions associated with head and neck squamous cell carcinoma (HNSCC).

Early detection of premalignant lesions and oral cancer.

Cancers of the oral cavity account for approximately 3% of malignancies diagnosed annually in the United States. As with other upper aerodigestive tract cancers, 5-year survival rates for oral cavity cancers decrease with delayed diagnosis. Cancers of the oral cavity are thought to progress from premalignant/precancerous lesions, beginning as hyperplastic tissue and developing into invasive squamous cell carcinoma. Despite the general accessibility of the oral cavity during physical examination, many malignancies are not diagnosed until late stages of disease. To prevent malignant transformation of these oral precursor lesions, multiple screening and detection techniques have been developed to address this problem.