Analysis of risk of death from differentiated thyroid cancer

Greater Local Recurrence Occurs with “Berry Picking” than Neck Dissection in Thyroid Cancer

Managing cervical lymph node metastases in well-differentiated thyroid cancer with either “berry picking” (BP) or anatomic neck dissection (AND) has not been shown to alter survival. Nevertheless local control of thyroid cancer is important. The purpose of this study is to determine whether the local recurrence rate of well-differentiated thyroid cancer is equivalent with BP versus AND. A retrospective analysis revealed 41 patients with well-differentiated thyroid cancer and cervical node metastases seen by a single surgeon from 1985 to 2002. A total of 83 initial and repeat neck operations were performed (nine BPs, 30 central neck dissections, and 44 modified radical neck dissections). Recurrence of cancer, intervention for recurrence, and complications of the BP and AND groups were evaluated. All nine (100%) patients undergoing a limited BP operation had local recurrence of cancer. Only three of the 32 (9%) patients undergoing an initial formal neck operation had local recurrence of tumor. The recurrences after BP (100%) were significantly greater than the recurrences after AND (9%) ( P < 0.001). The incidence of surgical complications with BP and AND was not different. Six of 32 (19%) initial formal neck dissection patients and four of nine (44%) BP patients had surgical complications. We conclude that BP is associated with greater local recurrence of thyroid cancer. Patients with nodal metastases should be managed with ANDs.

Carcinoma papilífero de alto risco da glândula tireóide: influência dos fatores prognósticos em 126 pacientes

OBJETIVO: Este trabalho tem como objetivo avaliar a influência dos fatores prognósticos em portadores de carcinoma papilífero da tireóide, tratados no Hospital do Câncer (INCA-RJ). MÉTODO: Com base em testes estatísticos (Wilcoxon e Cox) foram analisados 126 prontuários de pacientes atendidos no período de 1986 a 1994, portadores de carcinoma papilífero da tireóide, pertencentes ao grupo de alto risco, segundo os fatores de risco do carcinoma diferenciado da tireóide, considerando uma sobrevida de dez anos livre de doença. RESULTADOS: Observou-se que 104 pacientes eram mulheres (83%); a idade variou de sete a 79 anos, média de 40 anos; invasão capsular ocorreu em 15% (18/126); houve metástase regional em 38% (47/126) e metástase a distância em 11% (13/126). A sobrevida em dez anos livre de doença foi de 81% para os pacientes com menos de 45 anos, e de 76% para os mais idosos: p = 0,0008 (análise univariada) e p = 0,01 (análise multivariada). Dos pacientes que tinham invasão capsular, 72% viveram dez anos, assim como 60% dos que tinham metástase regional, e 28% dos que apresentavam metástase a distância. CONCLUSÕES: A utilização dos fatores de risco no carcinoma papilífero da tireóide é válida mesmo para doença avançada, sendo também de grande importância na projeção do prognóstico e do futuro desenvolvimento da doença.

Long-term outcome of patients with differentiated thyroid carcinoma: effect of therapy

OBJECTIVE

To present an overview of current therapeutic practices and results in patients with differentiated thyroid carcinoma.

METHODS

Personal series of patients and selected studies reported in the literature are reviewed relative to outcome (tumor recurrence and cancer-related mortality) after treatment of differentiated thyroid cancer.

RESULTS

In the United States, thyroid carcinoma ranks 14th in incidence among the major malignant tumors. Although many factors influence the long-term outcome with papillary and follicular thyroid carcinoma, the patient's age at the time of diagnosis, tumor stage, and initial treatment are the most important. The risk of death from thyroid cancer becomes substantially greater after age 40 years and increases dramatically after 60 years of age. Tumor recurrence is more prevalent before age 20 and after age 60 years. Delay in therapy for more than a year after initial manifestation also has been shown to have an adverse effect on outcome. The optimal initial treatment is usually near-total thyroidectomy and surgical excision of extrathyroidal tumor, when possible. For complete ablation of residual thyroid tissue, radioactive iodine therapy is usually necessary and should be followed by thyroid hormone suppression of serum thyrotropin concentrations. A schedule of 6-month follow-up intervals is recommended, until the serum thyroglobulin is undetectable and 131I whole-body scanning shows no uptake in the neck or extrathyroidal sites.

CONCLUSION

An aggressive approach to management of differentiated thyroid carcinoma is likely to render about 90% of patients permanently free of disease.

An overview of the management of papillary and follicular thyroid carcinoma

Long-term survival rate for papillary and follicular carcinoma is more than 90%, but this varies considerably among subsets of patients. About 30% of patients, however, develop tumor recurrence, depending on the initial therapy. Two-thirds of the recurrences occur within the first decade after therapy, but the others may appear years later. We found that among patients with recurrent cancer, 30% could not be fully eradicated and another 15% died of disease. Tumor recurred outside the neck in 21% of our patients, most commonly in the lungs (63%), which resulted in death in about half the patients. Mortality rates are lower when recurrences are detected early by radioiodine scans rather than by clinical signs. We believe that the best treatment for most patients with differentiated thyroid carcinoma is near-total thyroidectomy followed by 131I ablation of the thyroid remnant, which in our experience reduces the recurrence rate, improves survival and facilitates follow-up. A long delay in initiating this therapy has an adverse and independent effect on prognosis, more than doubling the 30-year cancer mortality rate. If only partial lobectomy has been performed, it is best to consider completion thyroidectomy for lesions 1 cm or larger because of the high rate of residual carcinoma in the contralateral lobe. Completion thyroidectomy and 131I whole-body scanning allows for the diagnosis and treatment of unrecognized carcinoma and when performed early, results in significantly fewer lymph node and hematogenous recurrences and enhances survival. A large and growing number of studies demonstrates decreased recurrence of papillary carcinoma and decreased disease-specific mortality attributable to 131I therapy. On the basis of our observations and other studies, we believe that an aggressive approach to initial management and follow-up may render nearly 90% of the patients permanently free of disease. Periodic follow-up should be done with whole-body scanning and serum thyroglobulin (Tg) measurements, performed either during thyroid hormone withdrawal or by recombinant human thyrotropin (TSH)-stimulated scanning and Tg measurement. A scheme for follow-up management is presented.

Thyroid carcinoma

During the past years advances have been made in the understanding of the molecular mechanisms involved in the initiation and progression of thyroid carcinoma. Mutations in tumor suppressor genes such as p53 and oncogenes such as N-ras may be important for progression of well-differentiated thyroid carcinomas. Activation of the ret protooncogene located on chromosomal region 10q11.2 has been identified as a key factor in the initiation of papillary and medullary carcinoma. Integration of these discoveries into a prognostic classification scheme may allow us to better predict the biologic behavior of tumors in individual patients. Despite the recent advances in our understanding of the molecular events occurring during thyroid carcinogenesis, major questions persist regarding aspects of patient management. New diagnostic modalities may enable us to noninvasively discriminate between benign and malignant thyroid nodules, and to detect recurrent disease earlier. Although the optimal surgical procedure for well-encapsulated tumors is still debated, recent clinical studies have shown that for those patients with tumors > 1.5 cm, the routine use of RAI and hormone suppression can improve local control and survival rates. Findings in two recent reviews suggest that patients with widely invasive thyroid masses benefit from the surgical removal of all gross tumor. Further investigation is required to define the role of adjuvant radiotherapy and the most appropriate management of unresectable disease. Incorporation of prognostic markers into clinical staging systems should allow surgeons to better tailor their treatment plans for each patient. Translation of recent basic science advances into the clinical arena may also aid in the development of novel treatment strategies for patients with aggressive tumors.

Incidence and clinical characteristics of thyroid carcinoma after iodine prophylaxis in an endemic goiter country

Iodized salt prophylaxis has been performed in Austria since 1963. Through this approach, mean urinary iodine excretion has been normalized to 144+/-23.5 microg/g creatinine per day. Thus Tyrol is no longer an endemic goiter area. We have analyzed the impact of iodized salt prophylaxis on thyroid cancer (TC) comparing data from the early 1960s with those corresponding to the period 1986 to 1995, when iodine supply was normalized. The study included 439 patients from Tyrol and Southern Tyrol. The incidence of TC in Tyrol has risen during the past decades from 3.07 between in 1957 and 1970 to 7.8 between 1990 and 1994 (CR/100000/year). We observed a rise in the percentage of differentiated adenocarcinomas (56% to 91.5%) with a predominance of papillary TC (54.4%) along with a decrease of anaplastic TC. In addition to these histological features, a shift to less advanced TNM stages, eg, T1-3, N0-1a, M0, was obvious, increasing from 29% to 72.2%, whereas advanced tumors, ie, T4 or N1b or M1, decreased from 71% to 28%. These changes have significantly improved prognosis. The current 5-year survival rate is 90.7% as compared with a rate of 73% in the 1960s; the values for 7-year survival are 89% and 48%, respectively. The marked effects of age, tumor stages, and histology on prognosis were confirmed with the Kaplan-Meier method. We conclude that together with normalization of iodine supply in an endemic goiter region the epidemiological profile of TC has changed. Even though the incidence of TC has risen, prognosis has significantly improved due to a shift towards differentiated forms of TC that are diagnosed at earlier stages.