Ototoxicity of cis-platinum and its relationship to eye colour

Abstract

The following hypothesis is presented: that the susceptibility of an individual patient to hearing loss as a result of cis-platinum administration can be predicted on the basis of eye colour. The rationale is that the melanin content of the inner ears is related to that of the eyes; dark eyes contain more melanin than lightcoloured eyes; and melanin causes the accumulation of the ototoxic drug within the inner ear. Hence those with dark eyes will suffer greater damage to the hearing than those with pale eyes. An investigation that confirmed this hypothesis is reported. In addition to cochlear damage there is a significant likelihood of damage to the auditory nerve as a result of the treatment.

Risk Factors for Hearing Loss in Patients Treated With Intensity-Modulated Radiotherapy for Head-and-Neck Tumors

“…However, a relationship between eye color and ototoxicity has been described in earlier studies, such that patients with dark eyes had more hearing loss after intravenously administered cisplatin chemotherapy (19,20). In experimental models, a high dose of cisplatin reduced the density of melanin in the high-frequency region of the cochlea in guinea pigs and thereby reduced the auditory brain stem responses at 30 kHz, suggesting a relation between melanin content and hearing status (21).…”

Achados audiológicos em pacientes tratados com radioterapia para tumores de cabeça e pescoço

“…The total radiotherapy dose varied between 60.0 Gy and 72.0 Gy -mean dose of 65.6 Gy and median dose of 64 Gy, with daily dose variation between 1.8Gy -2,0 Gy. As to radiotherapy mean treatment volume we found 1,743.8 cm 3 , median of 1,664 cm 3 and a variation of 768 cm 3 to 2,828 cm 3 . Among the 19 patients and 38 ears evaluated we noticed through the ENT evaluation that one ear had perforated tympanic membrane and 37 tympanic membranes were intact.…”

“…[2][3][4][5] Insofar as the ototoxic effects caused by radiation to the head and neck are concerned, the literature is full of controversies.…”

“…In a statistical analysis we compared the group of patients who received RTV in greater or lower than 1,800 cm 3 , and no significant auditory changes were seen among them. Therefore, for the sample investigated, the radiotherapy treatment volume was not considered an important risk factor for ototoxicity (Chart 3).…”

Grading of Iris Color with an Extended Photographic Reference Set

“…In most studies, iris color was subdivided in either 2 (light/dark, 5-9 blue/ brown, 10,11 or light-very light/black-brown 12 ), 3 (blue/greygreen/brown, 13,14 blue/mixture of brown, grey, green and/ or yellow/brown, 15 blue/grey-green-mottled/brown, 16 blue/ brown/other, 17 blue-grey/green-hazel/brown-black, 18 or blue/ green/brown 19 ), 4 (grey/blue/hazel/brown, 20 blue/grey-green/ hazel/brown, 21 blue/hazel/brown/indeterminate, 22 or blue/ brown/green/hazel 23 ), 5 (blue/grey/green/hazel/brown 24,25 or blue/hazel/green/brown/black 26 ), or 6 (blue/green/hazel/ brown/black/not clear 27 ) categories, to be assessed by the investigator and/or the subject. An extensive line of research has been devoted to the effects of prostaglandin analogs and prostamides on iris pigmentation.…”