Correlation of laryngeal and pharyngeal carcinomas and 24-hour pH monitoring of the esophagus and pharynx

The integrity and barrier function of porcine vocal fold epithelium: its susceptibility to damage by deoxycholic acid compared with pepsin

PURPOSE

In this study, we aim to systematically evaluate the damaging role of gastric (pepsin and acid) and duodenal ingredients (bile acids) on vocal fold epithelium in excised porcine larynges.

METHODS

Fresh ex vivo porcine larynges were exposed to one of five experimental conditions for 1 h. These conditions will be referred to as alkaline deoxycholic acid, acidic pepsin, acid pH3 only, acid pH5 only, and control, respectively. A Franz diffusing cell was used to evaluate the barrier function of vocal fold epithelium by measuring the permeability to fluorescein isothiocyanate dextran of 4 kDa. Histological changes were observed using transmission electron microscopy.

RESULTS

After immersing the fresh porcine larynges in the five solution groups, we found that the vocal fold epithelium in the deoxycholic acid group had more permeability to FD4 than the pepsin group (P < 0.001). Fragmentation and desquamation of dead cell layers were observed in both the pepsin and deoxycholic acid groups, but were more severe in the deoxycholic acid group than the pepsin group. The thickness of the dead epithelial cell layer gradually increased with increasing acid concentration (P < 0.05). Additionally, the thickness of the dead epithelial cell layer in the deoxycholic acid group was significantly higher than that in the pepsin group (P < 0.01).

CONCLUSION

Deoxycholic acid in a weakly acidic condition is more likely than pepsin to induce apoptosis in ex vivo porcine vocal fold epithelium, destroy the link proteins between epithelial cells, and affect their integrity and barrier function.

Experimental carcinogenesis on the oropharyngeal mucosa of rats with hydrochloric acid, sodium nitrate and pepsin

PURPOSE: To investigate the carcinogenic action of hydrochloric acid, pepsin and sodium nitrate on the oropharyngeal mucosa of rats, simulating the reflux of gastric contents. METHODS: Eighty-two Wistar rats were divided in seven groups and submitted to 2 or 3 weekly applications of hydrochloric acid, pepsin and sodium nitrate on the pharyngeal mucosa during six months. Study groups comprised 12 animals each. Rats in groups I and II were submitted to 2 (GI) or 3 (GII) weekly applications of 0.1N hydrochloric acid. Groups III and IV were submitted to 2 (GIII) or 3 (GIV) weekly applications of 0.1N hydrochloric acid solution with pepsin. Groups V and VI were submitted to 2 (GV) or 3 (GVI) weekly applications of 0.1N hydrochloric acid and treated with daily nitrate diluted in water. Group VII consisted of 10 animals submitted to 2 weekly applications of filtered water. RESULTS: No dysplasia, intra-epithelial neoplasia or invasive carcinomas were detected. Inflammatory changes were observed in varying degrees and mast cells were more common in Groups V and VI (p=0.006). CONCLUSION: The data of the current study could not corroborate the hypothesis that gastroesophageal and pharyngolaryngeal refluxes are carcinogenic factors to the laryngopharyngeal mucosa, and more studies are necessary in the future.

Is GERD a risk factor for laryngeal cancer?

OBJECTIVE/HYPOTHESIS

The significance of gastroesophageal reflux disease (GERD) in laryngeal cancer is controversial due to disparate studies. To evaluate the overall strength of the association of GERD with laryngeal cancer, we performed meta-analysis of the original studies in literature.

STUDY DESIGN

Meta-analysis.

METHODS

All studies cited on Ovid Medline (1966-June 2004), EMBASE (1980-June 2004), and Cochrane database describing GERD and laryngeal cancer were eligible for inclusion. The inclusion criteria for the study included original controlled study design and a clear documentation of the reflux prevalence in cases and controls. Statistical analysis was performed by NCSS software.

RESULTS

Fifteen original studies were identified. Eight studies did not have control groups, two studies did not clearly document GERD prevalence in controls, and two studies were published using the same data, one of which was included in this meta-analysis. Thus, four studies qualified for inclusion for the meta-analysis. The methodologic quality in the studies was heterogeneous, not only in the evaluation of confounding risk factors such as smoking and alcohol but also in the mode of GERD diagnosis. There was also significant heterogeneity of effect of reflux among the studies (P = .001). The pooled odds ratio on the basis of fixed-effects model was 2.86 (95% CI, 2.73-2.99), and on the basis of random-effects model was 2.37 (95% CI 1.38-4.08).

CONCLUSION

Our meta-analysis suggests that GERD may be a significant risk factor for laryngeal cancer. However, given the heterogeneity of the published data, future prospective controlled studies are needed.

Association between gastroesophageal reflux and sinusitis, otitis media, and laryngeal malignancy: a systematic review of the evidence

This study was conducted to review and evaluate the published evidence for an association between gastroesophageal reflux (GER) and 3 supraesophageal pathologies: sinusitis, otitis media, and laryngeal malignancy. Relevant articles were located using MEDLINE (search limits: 1966-2001, English language, human studies). Only new data or new analyses of previous data were included. Relevant articles were designated by their level of evidence, based on published standards, and grouped by pathology. An overall grade was assigned to each group for the strength of evidence for or against an association. The search produced 152 articles, 42 of which met inclusion criteria and were reviewed in detail. There is grade C evidence for a positive association between GER and sinusitis (57 articles screened, 14 articles included); for a negative association between GER and otitis media (28 articles screened, 10 articles included); and for a positive association between GER and laryngeal malignancy (67 articles screened, 18 articles included). The published literature weakly supports a positive association between GER and both sinusitis and laryngeal malignancy, and a negative association between GER and otitis media.