Radiation-induced xerostomia: is octreotide the solution?

In this study, we looked for evidence that octreotide, a drug used specifically in acromegaly and other digestive pathologies, can have a radioprotective effect on salivary glands. This effect has already been proven on the pituitary gland, which is why we postulated that octreotide could act the same way on rat parotid glands.

A prospective randomized controlled study on animals was conducted. With a noninvasive technique, we collected saliva from the parotid glands of 18 anesthetized rats at time 0 (preirradiation) and 1 month (postirradiation). Each sampling technique lasted 40 minutes, with pilocarpine injection at time 0 and 20 minutes. Saliva was collected bilaterally. Eighteen rats, nine in the saline group and nine in the octreotide group, were randomized. The substance was injected 30 minutes before irradiation. Thirty gray were given with the gamma knife on the left parotid gland of each rat following a computerized targeting method. Each gland was examined after the last saliva collection to determine the percentage of five criteria: fibrosis, ducts, fat, vessels, and acini.

Data are available for 17 rats (nine in the octreotide group and eight in the saline group). Statistical analysis was done with a t-test (independent and paired). We noted that the postirradiation secretion in the left (radiated) gland was diminished compared with the right (nonradiated) gland in the saline group (p = .014). Fibrosis was increased in the irradiated (left) gland in both groups (p = .024 in the octreotide group and p = .033 in the saline group). The percentage of duct cells was more important in the left (radiated) gland of the octreotide group (p = .046). A trend appeared for a decrease in acinic cells only in the control group (p = .063).

Octreotide acted as a radioprotective agent on rat parotid glands 1 month after irradiation with 30 Gy given with the gamma knife.