RESUMEN
Invasion of thyroid gland (TG) by laryngeal cancer is rare. However, ipsilateral hemithyroidectomy is routinely performed during total laryngectomy (TL) for laryngeal cancers. Even hemithyroidectomies are associated with hypothyroidism in 23-63% and hypoparathyroidism in 25-52%. Most of the studies on laryngectomy have advised thyroidectomy for T3 and T4 lesion, transglottic growth, subglottic disease or extension and involvement of anterior commissure. The role of tumour differentiation in TG invasion is unknown. The cases with TG invasion have been reported to have poorer prognosis. This is a retrospective study of 45 patients undergoing thyroidectomy along with TL. Of these, five had TG invasion. Extra-laryngeal soft tissue involvement [RR 1.89 (1.02, 4.24)] and transglottic growths [RR 1.18 (1.02, 1.36)] had a significant association with TG invasion. The mode of spread, contiguous or non-contiguous, depended on tumour differentiation. Well differentiated cancers had propensity for contiguous spread and moderately differentiated cancers for non-contiguous spread (p = 0.05). The 5 years survival of T4a cases was 30%. The difference in survival between TG invasion (p = 0.618), cartilage invasion (p = 0.111) and soft tissue infiltration (p = 0.474) was statistically insignificant. Anatomically direct TG invasion can only occur through extralaryngeal soft tissue which is includes cricopharyngeus and cricothyroid muscles. We recommend thyroidectomy only when these muscles are involved by the tumour in case of well differentiated cancers. The probability of TG invasion increases with transglottic growths with subglottic extension more than 10 mm. We recommend ipsilateral hemithyroidectomy in less differentiated cancers as they have propensity for non-contiguous spread.
RESUMEN
Black tea is more widely consumed than green tea worldwide, particularly in India. Therefore, it is necessary to focus attention on black tea with respect to its health promoting and anti-cancer actions. In order to establish the concept that black tea is a potential candidate for cancer prevention, it is important to provide epidemiological evidence derived from investigations of human populations. In view of this, the objective of the present study was to determine the correlation between nature of black tea consumption and DNA damage in normal subjects with or without tobacco habit and oral cancer patients, taking the latter as positive controls. Much experimental evidence points to associations between tobacco habit and HPV 16 and HPV 18 (Human Papilloma virus) infection. But no studies have taken into account the possible confounding effect of black tea consumption on DNA damage along with HPV infection. A pilot study was therefore undertaken. Comet assay was used to evaluate the DNA damage among normal subjects including tobacco users (n = 86), non-tobacco users (n = 45) and Oral cancer patients (n = 37). Percentage of damaged cells was scored in the buccal squamous cells of all subjects mentioned above. HPV analysis was performed on 79 samples (including 37 oral cancer patients). The evaluation of various confounding factors like age, tenure of tobacco habit and tea habit showed significant associations with DNA damage. The observations strongly indicate that regular intake of black tea at least above four cups can reduce tobacco associated DNA damage among normal tobacco users. HPV prevalence was not seen to be associated with age, tenure of tobacco habit or the tea drinking habit.
