| Wang et al., New York, NY, USA, evaluated the prognostic value of FDG-PET scanning in patients with thyroid carcinoma. Hundred twenty-five patients with previous total thyroidectomy and remnant ablation were included in the study and followed for 41 months during which 14/125 patients died. The results demonstrated that survival was reduced in those with: age > 45 yrs., distant metastases, a positive PET, high rates of FDG uptake, and volume of PET disease > 125 ml. Survival did not correlate with RAJ uptake, histology or gender. The single most strong predictor of survival was the volume of PET disease. The authors conclude that patients with these risk factors may need more aggressive therapy. Fatourechi et al., Rochester, MN, USA, studied the usefulness of post-therapy scans (PTS) in thyroglobulin-positive (> 20 ng/ml), diagnostic (3mCi) scan-negative patients with differentiated thyroid carcinoma with known metastases who had undergone thyroidectomy and radioiodine remnant ablation. Patients were treated with 100-300 mCi I-131 and PTS were obtained 3-4 days after therapy. Only in 1/21 patients with neck-, lung- and mediastinal metastases, PTS showed definite uptake in the metastases, 6/21 had questionable uptake in metastases. Of 15 patients with neck metastases 1/15 had definite, and 5/15 questionable uptake in the neck. Of 16 patients with lung metastases 1/16 had definite and 2/16 questionable uptake in the lungs. Uptake was seen in 1/5 patients with mediastinal metastases. In 0/5 patients with bone metastases uptake was visualized. Neither was metastases uptake present in 1 patient with brain metastases and another with kidney metastases. The authors conclude that in differentiated thyroid carcinoma patients with known metastases and a negative diagnostic scan, only a small number showed evidence of meaningful radioiodine uptake with high doses of I-131. "Blind" therapy according to the authors should not be encouraged. (Comment: This is still a controversial area. Other thyroidologists suggest that in this type of patients "blind" therapeutic dosis of I-131 do decrease Tg levels in serum that is regarded as a positive effect. It is unfortunate that in the present study any effect on serum Tg was not reported.) Biscolla et al., Sao Paulo, Brasil, performed a "nested" serum RT-PCR of Tg and NIS mRNA and compared the results with serum Tg protein determinations in the follow-up of 35 patients with differentiated thyroid carcinoma (19 papillary, 10 follicular, 6 mixed) who had undergone total thyroidectomy, while 16/35 also received postoperative radioiodine ablation. Studies were done during suppressive L-T4 therapy and 7/35 showed positive serum Tg. Using nested PCR, 14/35 patients showed positive Tg mRNA and 4/14 were also NIS mRNA positive. In 8/14 Tg mRNA positive patients serum Tg was undetectable. The authors conclude that nested PCR to detect Tg mRNA is a useful technique to detect Tg in carcinoma patients whose serum Tg is negative or who have circulating Tg autoantibodies. Sensitivity of NIS mRNA seems to be less than of Tg mRNA determination. (Comment: The main message of this study is that twice as many patients showed to be Tg (mRNA) positive as compared to serum Tg protein determination.) Lippi et al., Pisa, Italy, treated 12 patients with metastatic thyroid carcinoma after total thyroidectomy with or without subsequent I-131 therapy, with recombinant human rhTSH while they were kept on L-T4 suppressive therapy. RhTSH was administered once daily (0.9 mg i.m.) at two consecutive days. A peak TSH value was seen at day 3 ranging between 100-200 mU/L. The patients received two courses of rhTSH administration: one for a diagnostic scan and one for a therapeutic dose of I-131, both resulting in similar TSH reactivity. RhTSH administration promoted I-131 uptake in all patients. The authors conclude that administration of rhTSH is feasible without having to withdraw suppressive T4 therapy and thus inducing hypothyroidism. However, they state that long-term follow-up is necessary to judge the efficacy of this way of exogenous TSH stimulation as compared to endogenous (T4 withdrawal) TSH stimulation for administration of therapeutic doses of I-131. Sarkar et al., Long Island, NY, USA, reported about inhibition (stunning) of uptake in thyroid remnants and differentiated thyroid carcinoma metastases by diagnostic imaging using 5 mCi of I-131 upon subsequent (3-4 days later) uptake in these areas of therapeutic doses of I-131. Post-therapeutic uptakes as percentage of uptake of the diagnostic scan were for remnants (n = 15) between 4 and 42%, lung metastases (n = 3) between 41 and 73%, bone metastases (n = 7) between 26 and 100%, and lymphnode metastases (n = 2) between 21 and 58%. It is apparent from this study that especially thyroid remnants are stunned by diagnostic amounts of I-131 but to a lesser extent also uptake in metastases. (Comment: The question arises if, when using two courses of rhTSH, i.e. interrupted TSH stimulation (see previous report), stunning would also occur and, if so, to what extent.) Mandel et al., Philadelphia, PA, USA, administered 1.5 mCi I-123 to 15 consecutive patients after near-total thyroidectomy for papillary carcinoma for detection of residual thyroid tissue and/or metastases. They used low dose diagnostic I-123 to avoid stunning effect caused by beta-emission from I-131. In 10/15 patients, 5 hr and 24 hr I-123 images were equivalent, all had thyroid bed uptake, and 23 foci were visualized at both times. In 5/15 patients the 24 hr scan was superior and in 2/5 the 5 hr scan was negative but thyroid bed uptake was present at 24 hr. The general results of this study were that 24 hr scans using 1.5 mCi I-123 are superior over 5 hr scans. As the images showed excellent quality and could generate tomographic images (SPECT), these diagnostic scans appeared to be useful because of the lack of stunning. Alsanea et al., San Francisco, CA, USA, compared behaviour of familial non-medullary thyroid carcinoma (FNMTC) to that of sporadic non-medullary thyroid carcinoma (SNMTC). For each case three matched patients with SNMTC were selected. 31/462 patients with differentiated thyroid cancinoma, treated surgically between 1970-1999 ( 8 men), and 93 controls (24 men) were analyzed with a mean follow-up of 86 and 97 months respectively. Mean age 38 years vs 44 years. The average number of recurrences per patient was 0.7 vs 0.21 (p < 0.01). The authors conclude that FNMTC patients have more frequently recurrent disease than patients with SNMTC and furthermore that the former group has more bilateral and multifocal tumours. This difference could not be explained by the stage of the disease at presentation. Colombo-Benkmann et al., Heidelberg, Germany, retrospectively analyzed management and outcome of 38 patients (23 female, mean age 41 years) who underwent initial surgery for nodular thyroid disease but unexpectedly appeared to have medullary thyroid carcinoma (MTC). Initial surgery consisted of subtotal thyroidectomy in 25 patients, unilateral lobectomy in 3, and total thyroidectomy in 10, with selective lymphadenectomy in 5 patients. All patients subsequently underwent modified radical neck dissection. Fifteen years survival was 46% with sporadic MTC and 100% in patients with familial MTC (p <0.01). Furthermore, the higher the age of the patient at initial operation, the poorer the prognosis appeared to be (p = 0.002). (Comment: It was not reported if this age difference was explained by a poorer tumour stage at diagnosis.) Ceccarelli et al., Pisa, Italy, studied the effect of I-131 therapy on menopausal age in 130 women treated with I-131 for differentiated thyroid carcinoma with a mean dose of 143 mCi (range 10-1100 mCi) at the age < 45 years. The control group consisted of 127 goitrous women treated with suppressive L-T4 starting from the age < 45 years. The mean follow-up of the two groups was 9.1 and 8.8 years respectively. At the conclusion of the study, 79/105 of the carcinoma patients and excluding 25 patients with surgical menopause or using estrogens, were postmenopausal and of the goitrous patients (excluding 17 patients for the same reasons) 68/110. Of the carcinoma patients, 78 were still in observation at the age of 51 years and 63/78 (81%) were postmenopausal while these figures for the goitrous group were 68 and 47/68 (69%) respectively. Using the technique of survival analysis, the menopausal age of the carcinoma patients was significantly earlier than of the goitrous patients (p < 0.001). Liu et al., Winnipeg, MB, Canada, applied infrared spectroscopy to discriminate tumorous from normal thyroid cells in fine-needle aspirates. They found either after centrifugation of cells or in the original aspirates, but then using a supervised methodology such as the linear discriminant analysis, an accuracy of around 95%. The authors suggest that this method might be of use when cytology is negative. Görges et al., Mainz, Germany, evaluated imaging of thyroid tumours with somatostatin receptor scintigraphy (SRS) with imaging using I-131 and 18F-FDG positron emission tomography (PET). They found in 8/17 subjects with differentiated thyroid carcinoma SRS inferior to I-131, equal in 1/17, and superior in 8/17. In 18/23 patients with Hürthle cell carcinoma and metastases, SRS imaging showed various intensity of uptake while I-131 scans were negative in 22/23 patients. Accuracy of SRS and PET were similar in this last group of patients. There was no correlation between SRS uptake and the effect of somatostatin treatment. The authors suggest that SRS positive thyroid carcinomatous tissue might be treated with ß-emitting somatostatin analogs. Lennard et al., Bethesda, MD, USA, studied the relationship between intensity of vascular endothelial growth factor (VEGF) expression and prognosis of patients treated for differentiated thyroid carcinoma. Specimens from 59 patients (49 papillary, 10 follicular carcinoma) were scored (0-4) for immunohistochemical staining intensity of VEGF. Scores were significantly higher in patients with metastases at diagnosis than without (3.6 +/- 0.2 vs. 2.7 +/- 0.2, p = 0.001) and in those patients who later developed recurrent disease vs. no recurrence (3.7 +/- 0.2 vs. 2.6 +/- 0.2, p = 0.003). In summary, intensity of expression of VEGF is positively correlated with a poorer prognosis in differentiated thyroid carcinoma. (Comment: This is an interesting study. It would be of interest if this technique would be applied to differentiated carcinomas with a diameter of < 1 cm because these so-called occult tumours are reported to sometimes behave aggressively.) |
