Florent de Vathaire

AIM: The goal of this study was to estimate the cumulative activity of (131)I to be administered to patients with distant metastases from thyroid carcinoma. METHODS: A total of 444 patients were treated from 1953-1994 for distant metastases from papillary and follicular thyroid carcinoma: 223 had lung metastases only, 115 had bone metastases only, 82 had both lung and bone metastases, and 24 had metastases at other sites. Treatment consisted of the administration of 3.7 GBq (100 mCi) (131)I after withdrawal of thyroid hormone treatment, every 3-9 months during the first 2 yr and then once a year until the disappearance of any metastatic uptake. Thyroxine treatment was given at suppressive doses between (131)I treatment courses. RESULTS: Negative imaging studies (negative total body (131)I scans and conventional radiographs) were attained in 43% of the 295 patients with (131)I uptake; more frequently in those who were younger, had well-differentiated tumors, and had a limited extent of disease. Most negative studies (96%) were obtained after the administration of 3.7-22 GBq (100-600 mCi). Almost half of negative studies were obtained more than 5 yr after the initiation of the treatment of metastases. Among patients who achieved a negative study, only 7% experienced a subsequent tumor recurrence. Overall survival at 10 yr after initiation of (131)I treatment was 92% in patients who achieved a negative study and 19% in those who did not. CONCLUSION: (131)I treatment is highly effective in younger patients with (131)I uptake and with small metastases. They should be treated until the disappearance of any uptake or until a cumulative activity of 22 GBq has been administered. In the other patients, other treatment modalities should be used when tumor progression has been documented.

The late health effects associated with radioiodine ((131)I) given as treatment for thyroid cancer are difficult to assess since the number of thyroid cancer patients treated at each centre is limited. The risk of second primary malignancies (SPMs) was evaluated in a European cohort of thyroid cancer patients. A common database was obtained by pooling the 2-year survivors of the three major Swedish, Italian, and French cohorts of papillary and follicular thyroid cancer patients. A time-dependent analysis using external comparison was performed. The study concerned 6841 thyroid cancer patients, diagnosed during the period 1934-1995, at a mean age of 44 years. In all, 17% were treated with external radiotherapy and 62% received (131)I. In total, 576 patients were diagnosed with a SPM. Compared to the general population of each of the three countries, an overall significantly increased risk of SPM of 27% (95% CI: 15-40) was seen in the European cohort. An increased risk of both solid tumours and leukaemias was found with increasing cumulative activity of (131)I administered, with an excess absolute risk of 14.4 solid cancers and of 0.8 leukaemias per GBq of (131)I and 10(5) person-years of follow-up. A relationship was found between (131)I administration and occurrence of bone and soft tissue, colorectal, and salivary gland cancers. These results strongly highlight the necessity to delineate the indications of (131)I treatment in thyroid cancer patients in order to restrict its use to patients in whom clinical benefits are expected.

We assessed the results of treatment in 283 patients with lung or bone metastases from differentiated thyroid carcinoma who were followed for up to 40 yr (median, 44 months) after the discovery of the metastases. The survival rates from the time of discovery of the metastases were 53% at 5 yr, 38% at 10 yr, and 30% at 15 yr; 156 patients died. Multivariate analysis revealed that only 4 variables had an independent prognostic significance for survival. They were extensive metastases, older age at discovery of the metastases, absence of radioiodine uptake by the metastases, and moderately differentiated follicular cell type. The site of metastases (lung or bone) was not a prognostic factor for survival after treatment of metastatic disease. Remission was achieved in 79 patients after metastases were found. The only predictive factor for 5-yr disease-free survival after treatment of metastases was the initial extent of disease. Our results suggest that the aim of management should be to detect and treat metastases in patients with thyroid cancer as early as possible.

We assessed the therapeutic benefits of 131I treatment in patients with distant metastases of differentiated thyroid carcinoma.Of 2200 patients treated for differentiated thyroid carcinoma at our institution, 394 had lung and/or bone metastases.Two-thirds of the patients had 131I uptake in their metastases, but only 46% achieved a complete response. Prognostic factors for complete response were: younger age, presence of 131I uptake in the metastases and small extent of disease. The survival rate was 33% at 15 yr. As shown by multivariate analysis, favorable prognostic factors for survival were: younger age and time of metastases detection, well-differentiated histologic type of the thyroid tumor, presence of 131I type uptake in the metastases, small extent of the disease and year of discovery of metastases.In terms of survival, the benefits of 131I therapy cannot be demonstrated by prospective controlled studies. The present study clearly demonstrates, however, that treatment with 131I is one of the factors which accounts for survival; patients whose metastases concentrated 131I and who could be treated with radioiodine had higher survival rates. Patients who achieved complete response following treatment of distant metastases had a 15-yr survival rate of 89%, while those who did not achieve complete response had a survival rate of only 8%. The survival rate improved with the year of discovery of distant metastases, after 131I total-body imaging and serum thyroglobulin measurements were routinely used.

PURPOSE: The purpose of this study was to assess the role of treatment in long-term overall and cardiovascular mortality after childhood cancer. PATIENTS AND METHODS: We studied 4,122 5-year survivors of a childhood cancer diagnosed before 1986 in France and the United Kingdom. Information on chemotherapy was collected, and the radiation dose delivered to the heart was estimated for 2,870 patients who had received radiotherapy. RESULTS: After 86,453 person-years of follow-up (average, 27 years), 603 deaths had occurred. The overall standardized mortality ratio (SMR) was 8.3-fold higher (95% CI, 7.6-fold to 9.0-fold higher) in relation to the general populations in France and the United Kingdom. Thirty-two patients had died as a result of cardiovascular diseases (ie, 5.0-fold [95% CI, 3.3-fold to 6.7-fold] more than expected). The risk of dying as a result of cardiac diseases (n = 21) was significantly higher in individuals who had received a cumulative anthracycline dose greater than 360 mg/m(2) (relative risk [RR], 4.4; 95% CI, 1.3 to 15.3) and in individuals who received an average radiation dose that exceeded 5 Gy (RR, 12.5 and 25.1 for 5 to 14.9 Gy and > 15 Gy, respectively) to the heart. A linear relationship was found between the average dose of radiation to the heart and the risk of cardiac mortality (estimated excess [corrected] RR at 1 Gy, 60%). CONCLUSION: This study is the first, to our knowledge, to establish a relationship between the radiation dose received by the heart during radiotherapy for a childhood cancer and long-term cardiac mortality. This study also confirms a significant excess risk of cardiac mortality associated with a high cumulative dose of anthracyclines.