AIMS:Salivary gland toxicity is a common, but not widely appreciated, adverse effect of high-dose radioiodine (131I). This study was carried out to determine the incidence of symptoms of salivary gland damage after 131I treatment for differentiated thyroid cancer. MATERIALS AND METHODS:This was a prospective study of 76 consecutive patients attending thyroid cancer treatment. Symptoms of salivary gland damage (dry mouth, pain and swelling) were assessed during hospital admission and at follow-up visits. Additionally, a retrospective analysis was carried out of patients recorded in our database as having chronic salivary gland swelling after 131I ablation. RESULTS:Twenty patients (26%) developed salivary gland toxicity, 11 (15%) had symptoms within the first 48 h, continuing for 12 months in seven of these patients. The onset of toxicity in a further nine (12%) patients with persistent symptoms did not occur until 3 months after therapy. In total, 16 (21%) patients had evidence of chronic toxicity, typically xerostomia, at 12 months. Toxicity was more common after repeated 131I administration. After searching our thyroid cancer database, we identified an additional five patients to have chronic salivary gland swelling (chronic sialadenitis or pleomorphic adenoma) 20 months to 23 years after 131I. CONCLUSIONS:Pain, swelling and dry mouth occurred frequently after 131I, with some developing symptoms months or years after administration. Early recognition of salivary gland complications may help to reduce morbidity in these patients.

IntroductionIdeally, the administration of radioiodine (RAI) therapy for the treatment of differentiated thyroid cancer (DTC) would be carried out on a patient-specific basis. This requires individual dosimetry calculations. AimTo calculate whole-body absorbed doses (WBD) and blood doses (BD) resulting from different levels of administration, to determine whether a correlation exists between the levels of administered activity and these toxicity criteria. MethodsEighty-two patients underwent 110 treatments. Serial whole-body activity measurements were taken following administration of 3, 5.5 and 9 GBq RAI. Blood samples were taken at 48, 72 and 144 h for similar evaluations. WBD and BD were calculated using standard MIRD methodology with interpolated S values. ResultsWBD and BD values are expressed as mean±SD Gy. After 3 GBq, WBD=0.18±0.04, BD=0.31±0.08; after 5.5 GBq, WBD=0.34±0.14, BD=0.64±0.38; and after 9 GBq, WBD=0.66±0.39, BD=0.94±0.44. Whilst higher administered activities resulted in higher absorbed whole-body and blood doses, no adverse haematological toxicity was observed throughout the study. ConclusionThe determination of absorbed whole-body and blood doses can be used as a guide to the safe prescription of administered activity up to 9 GBq. These methods can help predict and minimize potential toxicity.

Introduction Ideally, the administration of radioiodine (RAI) therapy for the treatment of differentiated thyroid cancer (DTC) would be carried out on a patient-specific basis. This requires individual dosimetry calculations. Aim To calculate whole-body absorbed doses (WBD) and blood doses (BD) resulting from different levels of administration, to determine whether a correlation exists between the levels of administered activity and these toxicity criteria. Methods Eighty-two patients underwent 110 treatments. Serial whole-body activity measurements were taken following administration of 3, 5.5 and 9 GBq RAI. Blood samples were taken at 48, 72 and 144 h for similar evaluations. WBD and BD were calculated using standard MIRD methodology with interpolated S values. Results WBD and BD values are expressed as mean±SD Gy. After 3 GBq, WBD=0.18±0.04, BD=0.31±0.08; after 5.5 GBq, WBD=0.34±0.14, BD=0.64±0.38; and after 9 GBq, WBD=0.66±0.39, BD=0.94±0.44. Whilst higher administered activities resulted in higher absorbed whole-body and blood doses, no adverse haematological toxicity was observed throughout the study. Conclusion The determination of absorbed whole-body and blood doses can be used as a guide to the safe prescription of administered activity up to 9 GBq. These methods can help predict and minimize potential toxicity.

OBJECTIVE: To assess the value of the diagnostic whole body (131)I scan after thyroidectomy and (131)I ablation. DESIGN: Retrospective analysis of all patients with differentiated thyroid cancer treated in one centre between 1990 and 2000. RESULTS: A total of 153 consecutive patients who underwent diagnostic scanning following ablative therapy were identified. This diagnostic scan was positive in 20 patients (13%) and faintly positive in 16 patients (11%). The majority (117 patients) had negative scans. Of the 20 patients with positive scans, four received no further treatment, nine showed no abnormal uptake following a second ablative (131)I dose and seven had uptake in the thyroid bed (six) or in neck nodes (one) after repeat ablation. OUTCOME: In the group with positive scans, the four patients who received no further treatment and the nine with a negative second ablation scan remained disease free during follow-up. No patient with a positive diagnostic scan received additional (131)I therapy which would not otherwise have been given based on the clinical findings, serum thyroglobulin (Tg) values or the presence of anti-Tg antibodies. Ten of the patients with negative scans developed recurrent disease which was always detected clinically or by a rising serum Tg value. CONCLUSIONS: Diagnostic whole body (131)I scans add little extra information and in our experience do not influence patient management. They should be reserved for patients in whom serum Tg levels are unreliable because of the presence of antibodies or when there is clinical suspicion of tumour.

The aim of this study was to review the outcome of ablative radioiodine treatment on ovarian function in young women treated for differentiated thyroid carcinoma. Of 1398 patients with differentiated thyroid cancer, 496 were women under the age of 40 at the time of diagnosis who had received radioiodine therapy. Of these, 322 received a single 3 GBq ablation dose of radioiodine while the remainder received subsequent treatment with (131)I with a cumulative activity of 8.5-59 GBq for residual, recurrent, or metastatic disease. Transient amenorrhoea or menstrual irregularities lasting up to 10 months were experienced in 83 patients (17%). No cases of permanent ovarian failure were recorded. There were 427 children born to 276 women; only one patient wishing to achieve a successful pregnancy outcome has been unsuccessful. Four premature births and 14 miscarriages occurred but no congenital abnormalities were reported. The risk of permanent damage to the ovaries after ablative radioiodine treatment appears to be low and patients can be reassured they can have normal pregnancies after this treatment.

OBJECTIVE Young adults with differentiated thyroid cancer are treated with high doses of radioiodine and have an excellent long-term prognosis. However, there is limited information on the effects of this treatment on the gonads and fertility in male patients. We have reviewed the outcome of treatment in our centre with respect to male fertility. We have also assessed directly the radiation dose received by the testes.DESIGN Retrospective analysis of males attending the thyroid clinic at the Royal Marsden Hospital for treatment of differentiated thyroid cancer. A prospective study was also performed to assess radiation dose to testes in 14 consecutive patients attending for thyroid cancer treatment.PATIENTS Males under the age of 40 years at the time of treatment with a minimum of 3 years follow-up.MEASUREMENTS Number of children fathered by patients and number of congenital malformations. For the prospective study: gonadal function assessed by serum FSH, LH and testosterone measurements; radiation dose to the testes (Gy) measured by thermoluminescent dosimetry.RESULTS Fertility was assessed in 122 men with a median follow-up of 21 years (range 3-39) of whom 93 were under active follow-up. One hundred and six children were fathered by 59 patients; the remainder had no wish to have children. No major malformations were reported. Of these 59 patients, 12 had received a single 3GBq ablation dose, 19 had been treated with up to 14 GBq radioiodine and 28 had received up to 44 GBq. In 14 patients followed prospectively, the median estimated radiation dose to each testis was 6.4 cGy following 3 GBq, 14.1 cGy following 5.5 GBq and 21.2 cGy following 9.2 GBq. There was a transient elevation in serum FSH after radioiodine which normalized within 9 months from the last administration.CONCLUSIONS Radioiodine treatment for thyroid cancer may result in transient impairment of gonadal function. The radiation dose absorbed by the testis after a single ablative dose of radioiodine is well below that associated with permanent damage to germinal epithelium and the risk of infertility in these patients is minimal. Patients requiring multiple administrations for persistent or metastatic thyroid cancer may be at greater risk of gonadal damage although even in this group, we found no evidence of infertility.

An analysis of the outcome of thyroid carcinoma incidentally discovered in patients undergoing surgery for hyperthyroidism is presented. Among 986 patients with differentiated thyroid cancer, 23 had presented with symptoms and signs of hyperthyroidism. Graves' disease was diagnosed in 11, multinodular goitre in eight and toxic adenoma in four. Following thyroidectomy, histology revealed papillary (18), follicular (four) and Hurthle cell (one) carcinoma. Tumour size ranged from 4 mm to 5.5 cm, multifocality was detected in three patients, and lymph node involvement in one. Two patients (one with associated Graves' disease, one with multinodular goitre) relapsed locally and required further surgery; one developed distant metastases and died 7 years after initial presentation. Two patients died of unrelated causes; the remaining 20 patients are alive and well with a median follow-up of 16 (1-34) years. Differentiated thyroid cancer found incidentally at surgery for hyperthyroidism has a good prognosis.

Objective: To assess the outcome of thyroid cancer diagnosed during pregnancy.Design: Retrospective analysis of patients diagnosed between 1949 and 1997 with thyroid cancer presenting during pregnancy.Results: Nine women with a median age of 28 years were identified. A thyroid nodule was discovered by the clinician during routine antenatal examination in four cases, the remainder had noted a lump in the neck. In all patients, the nodule was reported to almost double in size during the pregnancy, One patient underwent subtotal thyroidectomy during the second trimester: eight were operated on within 3 to 10 months from delivery. Total thyroidectomy was performed in five and subtotal thyroidectomy in four. All tumours were well differentiated and ranged in size from 1 to 6 cm.Outcome: The median follow-up was 14 years (5-31 years). One patient relapsed locally requiring further surgery. One patient developed bone metastases dying 7 years after presentation; her planned treatment had been delayed because of an intervening pregnancy. Eight of the original cohort of patients are currently disease free.Conclusions: Differentiated thyroid cancer presenting in pregnancy generally has an excellent prognosis. When the disease is discovered early in pregnancy, surgery should be considered in the second trimester but radioiodine scans and treatment can be safely delayed until after delivery. In all cases, treatment should not be delayed for more than a year.