Circulating thyroglobulin measurements by homologous radioimmunoassay in dogs with thyroid carcinoma

Abstract

Circulating thyroglobulin was measured in 20 dogs with thyroid cancer, using a homologous polyclonal radioimmunoassay. Plasma Tg levels exceeded the normal range in 14 (70%) dogs, and ranged from 6 to 2902 \g=m\g/l(median 608). Plasma Tg levels tended to decrease from follicular carcinomas to solid-follicular carcinomas, to solid carcinomas (p<0.05). Plasma Tg levels were also higher in scintigraphically hot tumours than in cold ones. Other relationships between circulating Tg and clinical, pathological, and functional parameters were not found, except a poor (R=0.49) but significant (p=0.04) correlation between Tg and T4 levels. Plasma Tg was measured before surgery and at least once during followup, in 9 dogs. After hemithyroidectomy, a decrease was observed in 8 dogs. In 7 of these 8 dogs, plasma Tg levels declined within the reference range at the first postoperative sample. In the ninth dog, where metastases were detected 14 months after surgical treatment, plasma Tg slightly increased, yet within normal range. It is concluded that measurement of plasma Tg levels might be useful for monitoring the postoperative course of the disease in individual dogs with thyroid cancer.

Post-surgical treatment of thyroid carcinoma in dogs with retinoic acid 9 cis improves patient outcome

“…1). According to the radiotracer concentration (uptake) in the gammagraphy study, (Verschueren et al, 1991) tumours were classified as hot (high uptake compared to the contralateral lobe and the salivary glands that are inhibited), cold (low uptake with respect to the contralateral lobe and salivary glands, with normal uptake), or normal-uptake (both thyroid lobes uptake and the salivary glands uptake are equals). Dogs that presented any lymph node affected with local invasion or distal metastasis were excluded from the experiment.…”

“…There are few reports regarding the relation among thyroid carcinoma functionality and/or TC histopathology. Regarding the functional characteristics, Verschueren et al (1991) reported that the greater the undifferentiated thyroid carcinoma profile, the less binding sites for TSH and 99m Tc uptake were found. Similarly, a greater expression of thyroglobulin and TSH-R was found in follicular cells within the carcinoma tissue where the remaining thyroid follicle architecture was found.…”

“…The histological origin of dFTC tumours will influence its progression, local invasion, tumour recurrence after surgery, and median survival time (Haugen, 1999). However, the dFTC functional characteristics (iodine uptake, thyroid hormones synthesis) vary by histological origin (Verschueren et al, 1991). The median survival time for dogs with untreated thyroid carcinoma is only three months (Worth et al, 2005), but in freely movable non-metastatic thyroid tumours, the median survival time with surgery alone has been reported to be from 7-8 months (Page, 2001;Morris and Dobson, 2002) to over 36 months (Klein et al, 1995).…”

“…Radiation is not effective when 99m Tc uptake does not occur because poor uptake only occurs in poorly differentiated tumours or undifferentiated tumours (Worth et al, 2005;Turrel et al, 2006). In dFCT cases, radiation therapy has been associated with a median survival time of 28 months (Verschueren et al, 1991;Turrel et al, 2006). Despite the apparent success of surgery and radiation in the management of localized TC, up to 80% of canine patients have recurrences of TC or develop metastases during the course of their disease (Patnaik and Lieberman, 1991;Carver et al, 1995;DeLellis, 2004;Kiupel et al, 2008;Sipos et al, 2008;Wucherer et al, 2010).…”