Conservative management of patients with intrathyroidal well-differentiated follicular thyroid carcinoma

Microscopic extrathyroid extension in papillary thyroid carcinoma: impact on response to therapy

Objectives Evaluate the impact of microscopic extrathyroid extension (MEE) on outcome and therapy response in patients with cT1 and cT2 papillary thyroid carcinoma (PTC). Subjects and methods Retrospective study of 970 consecutive patients, who underwent surgery for PTC between 2000 and 2016. All patients had: tumours ≤ 4 cm, apparent complete tumour resection, without clinically apparent lymph node or distant metastasis at diagnosis and nonaggressive histologic variant. Results Based on the finding of MEE, 175 (18.0%) patients were upstaged to T3. They were older (53.9 versus 50.6 years; P = 0.004) and were more prone to have multifocal tumours (38.2% versus 24.8%; P = 0.001). Radioiodine ablation therapy (RAI) was administered more often to MEE patients (92% versus 40.5%; P < 0.001), as well as prophylactic lymph node resection (35.4% versus 28.6%, P = 0.048). They were more likely to have biochemical incomplete response (4% versus 0.3%; P = 0.03) at the end of the follow-up period. There was no significant association between MEE and recurrence rate, persistence of disease or disease-specific mortality. Conclusion These results support the changes made to the latest edition of the TNM staging system, regarding MEE. Although incomplete biochemical response is more common in these patients, it does not seem to affect their prognosis.

The impact of microscopic extrathyroid extension on outcome in patients with clinical T1 and T2 well-differentiated thyroid cancer

OBJECTIVE

To report the impact of microscopic extrathyroid extension (ETE) on outcome in patients with cT1/cT2 well-differentiated thyroid cancer (WDTC), and to determine the effect of extent of surgery and adjuvant radioactive iodine (RAI) treatment on outcome in patients with microscopic ETE.

PATIENTS AND METHODS

From an institutional database, we identified 984 patients (54%) who underwent surgery for cT1/T2N0 disease. Of these, 869 patients were pT1/T2 and 115 were upstaged to pT3 based on the finding of microscopic ETE. Disease-specific survival (DSS) and recurrence-free survival (RFS) were analyzed for each group using the Kaplan-Meier method. In the pT3 group, factors predictive of outcome were analyzed by univariate and multivariate analyses.

RESULTS

There was no difference in the 10-year DSS (99% vs 100%; P = .733) or RFS (98% vs 95%; P = .188) on comparison of the pT1/pT2 and pT3 cohorts. Extent of surgery and administration of postoperative RAI were not significant for recurrence on univariate or multivariate analysis in the pT3 cohort.

CONCLUSION

Outcomes in patients with cT1T2N0 WDTC are excellent and not affected by microscopic ETE. The extent of resection and administration of postoperative RAI in patients with microscopic ETE does not impact survival or recurrence.

[Minimally invasive follicular thyroid carcinoma : Not always total thyroidectomy]

Current treatment guidelines for follicular thyroid carcinoma (FTC) recommend total thyroidectomy, lymphadenectomy and radioiodine ablation. Considering the low malignant potential of minimally invasive follicular thyroid carcinoma (MIFTC), a limited radical therapeutic procedure may be adequate. MIFTC is an intensely discussed group of tumors and a review of the literature reveals disagreement among experts concerning the criteria for a distinct definition. Therefore, in 2005 Rosai proposed a clinically more significant classification of FTC based on the extent of capsular and vascular invasion: MIFTC with capsular invasion only, with limited (< or =3) vascular invasion, encapsulated FTC with extensive (>3) vascular invasion and broadly invasive FTC with extensive invasive growth.For the diagnosis of MIFTC a complete investigation of the encapsulated follicular lesion should be performed by the pathologist and examination of at least 10 tissue blocks is mandatory. Due to the excellent prognosis hemithyroidectomy constitutes an adequate therapeutic approach in MIFTC with capsular invasion only and may also be considered for MIFTC with limited vascular invasion. There are no indications for systematic lymphadenectomy.

The effectiveness of radioactive iodine for treatment of low-risk thyroid cancer: a systematic analysis of the peer-reviewed literature from 1966 to April 2008

BACKGROUND

Radioactive iodine (RAI) remnant ablation has been used to eliminate normal thyroid tissue and may also facilitate monitoring for persistent or recurrent thyroid carcinoma. The use of RAI for low-risk patients who we define as those under age 45 with stage I disease or over age 45 with stage I or II disease based on American Joint Committee on Cancer (AJCC) 6th edition, or low risk under the metastases, age, completeness of resection, invasion, size (MACIS) staging system (value <6) is controversial. In this extensive literature review, we sought to analyze the evidence for use of RAI treatment to improve mortality and survival and to reduce recurrence in patients of various stages and disease risk, particularly for those patients who are at low risk for recurrence and death from thyroid cancer.

METHODS

A MEDLINE search was conducted for studies published between January 1966 and April 2008 that compared the effectiveness of administering versus not administering RAI for treatment of differentiated thyroid cancer (DTC). Studies were grouped A through D based on their methodological rigor (best to worst). An analysis, focused on group A studies, was performed to determine whether treatment with RAI for DTC results in decreased recurrences and improved survival rates.

RESULTS

The majority of studies did not find a statistically significant improvement in mortality or disease-specific survival in those low-risk patients treated with RAI, whereas improved survival was confirmed for high-risk (AJCC stages III and IV) patients. Evidence for RAI decreasing recurrence was mixed with half of the studies showing a significant relationship and half showing no relationship.

CONCLUSIONS

We propose a management guideline based on a patient's risk-very low, low, moderate, and high-for clinicians to use when delineating those patients who should undergo RAI treatment for initial postoperative management of DTC. A majority of very low-risk and low-risk patients, as well as select cases of patients with moderate risk do not demonstrate survival or disease-free survival benefit from postoperative RAI treatment, and therefore we recommend against postoperative RAI in these cases.

Follicular carcinoma arising from the pyramidal lobe of the thyroid

We present a rare case of follicular carcinoma arising from the pyramidal lobe of the thyroid in a 21-year-old woman. Radical resection of the thyroid isthmus was performed, followed by adjuvant hormonal therapy with levothyroxine. After 15 months of follow-up, the patient remains disease-free. Thyroid carcinoma in children and adolescents is rare, and also rarely arises in the pyramidal lobe. To our knowledge, this is the first report of this type of neoplasm arising from the thyroid pyramidal lobe. We are following up this case carefully, and if recurrence or metastasis or both occur, we plan to perform total thyroidectomy and ablation with (131)I. This case suggests the importance of the differential diagnosis of midline cervical masses and the management of this type of neoplasm in adolescents.

Surgical approaches in thyroid cancer and lymph-node metastases

Thyroid cancer collectively encompasses a variety of tumors of disparate morphology and biology. With the exception of radio-iodine therapy for iodine-concentrating well-differentiated thyroid cancers, surgery is the foremost and generally sole effective treatment. Because the growth patterns of these tumors vary tremendously, there is a need to tailor the extent of dissection to the respective tumor entity, especially for less aggressive tumors. No international consensus exists about what precisely constitutes a 'low-risk' or 'high-risk' tumor. Established indications for less-than-total thyroidectomy include small (<or=1 cm), unifocal, and non-metastatic papillary thyroid carcinomas (PTC), and minimally invasive follicular thyroid carcinomas (FTC; invasion of the tumor capsule only). Whether occult multifocal PTC and minimally invasive FTC with histopathological evidence of vascular invasion also fall into the 'low-risk' category remains unclear. For node-positive thyroid cancers, compartment-oriented microdissection is the gold standard of care, whereas the concept of prophylactic lymph-node dissection continues to arouse controversy. Most experts agree that routine lymph-node dissection is unnecessary for low-risk well-differentiated thyroid cancer (DTC). Because occult lymph-node metastases are frequent in high-risk PTC and medullary thyroid carcinoma, compartment-oriented microdissection helps prevent reoperations for 'recurrences' arising from residual nodes, sparing patients the excess morbidity from reoperations in the neck. Because of the looming epidemic of early forms of thyroid cancer, an international consensus is needed regarding (1) the definition of low- versus high-risk tumors; (2) classification of neck nodes; and (3) lymph-node dissection terminology.

An updated systematic review and commentary examining the effectiveness of radioactive iodine remnant ablation in well-differentiated thyroid cancer

Radioactive iodine remnant ablation (RRA) is used to destroy residual normal thyroid tissue after complete gross surgical resection of papillary or follicular thyroid cancer. The article updates a prior systematic review of the literature to determine whether RRA decreases the risk of thyroid cancer-related death or recurrence at 10 years after initial surgery, including data from 28 studies. No long-term randomized trials were identified, so the review is limited to observational studies. The incremental benefit of RRA in low risk patients with well-differentiated thyroid cancer after total or near-total thyroidectomy who are receiving thyroid hormone suppressive therapy remains unclear.

Endoscopic transaxillary approach to the thyroid gland: our early experience

BACKGROUND

Thyroid nodules are a common occurrence in clinical practice today. Most nodules are benign and can be managed nonoperatively with careful medical follow-up. However surgical extirpation occasionally becomes necessary to exclude a malignant neoplastic process. Although the majority of surgically excised thyroid lesions are histologically benign, patients are traditionally left with a permanent transverse surgical scar in a highly visible area of the neck.

MATERIALS AND METHODS

From August 2003 to August 2005, we performed a transaxillary endoscopic thyroid lobectomy with isthmectomy in 32 patients. We used a 3-port technique with 5-mm trocars and surgical instrumentation. A 5-mm 45-degree angled endoscope was used for visualization during the procedure. The CO(2) insufflation pressure was set to 6-8 mmHg, and dissection was carried out using a 5-mm harmonic scalpel (Ethicon Endo-Surgery).

RESULTS

All patients underwent successful completion of thyroid lobectomy and isthmectomy. No conversion to open operation was required in this series. The mean operating time was 138.5 min, and the mean blood loss was 36.4 ml. The recurrent laryngeal nerve was identified in each case, and there was no permanent injury to this structure. There were two cases of temporary hoarseness that resolved spontaneously. One patient in this series had to be returned to the operating room for evacuation of a postoperative hematoma from an active bleeding vessel on the surface of the pectoralis major muscle. All patients were discharged on the first postoperative day.

CONCLUSIONS

Transaxillary endoscopic thyroidectomy is a safe and feasible alternative to the traditional open surgical approach in select patients requiring surgical removal of the thyroid gland. The resultant improved cosmetic outcome and enhanced operative visualization may offer a practicable alternative for select patients requiring surgical removal of the thyroid gland.

Gasless endoscopic thyroidectomy via an axillary approach: experience of 30 cases

Surgery for thyroid disease requires skin incisions that can result in postsurgical problems such as prominent scars, adhesions, hypesthesia, and paresthesia in the neck. To overcome these problems we performed gasless endoscopic thyroidectomy via an axillary approach. Between May 2004 and April 2005, 30 patients underwent gasless endoscopic thyroidectomy via an axillary approach. The mean operating time was 126.8+/-32.4 minutes, and the mean length of hospital stay was 4.3+/-1.1 days. No cases required conversion to open surgery and none involved significant intraoperative complications. Three patients (10.0%) complained of slight hypesthesia or paresthesia in the anterior chest wall, and only 2 patients (6.7%) complained of discomfort while swallowing 4 months after surgery. All patients were satisfied with the cosmetic results. Gasless endoscopic thyroidectomy via an axillary approach is feasible and safe and provides excellent cosmetic results with a minimal degree of postoperative complaints.

Follicular thyroid carcinoma: the role of histology and staging systems in predicting survival

OBJECTIVE

To evaluate the risk factors including tumor histomorphology for survival specific to follicular thyroid carcinoma (FTC) and to apply commonly employed staging systems in predicting survival for patients with FTC.

SUMMARY BACKGROUND DATA

FTC is usually analyzed collectively with papillary thyroid carcinoma (PTC) in risk group analysis. Risk factors and risk group analysis are important in the management of patients with FTC, although current published therapeutic guidelines call for total thyroidectomy followed by radioactive iodine (I) ablation for all FTC patients.

METHODS

Over a 40-year period, 156 patients surgically treated for FTC with an average follow-up of 14.4 years were retrospectively studied after histologic reclassification according to the type and degree of invasiveness of the tumor. Potential risk factors for survival were calculated using multivariate analysis, and the prognostic accuracy of AMES risk group stratification, UICC/AJCC pTNM staging, Degroot classification, and MACIS scoring schemes in predicting survival was compared.

RESULTS

Seventeen (11%) patients had distant metastases at presentation, and bilateral thyroid resection was performed for 131 (84%) patients. Seventeen (11%) patients died of recurrent or metastatic disease. The overall and cancer-specific survival (CSS) rates at 10 years were 79% and 88%, respectively. None of the patients with minimally invasive (n = 49) or angioinvasive (n = 23) carcinomas died compared with 17 of 84 patients with widely invasive carcinomas (P = 0.0007). Using the Cox proportional hazards model, old age, the presence of distant metastases, and incomplete tumor excision were independent prognostic factors for survival. For patients who underwent curative treatment, old age and widely invasive carcinoma were risk factors for poor survival. All staging systems studied accurately predicted CSS, and the pTNM UICC/AJCC staging system yielded the best prognostic information.

CONCLUSIONS

Commonly adopted staging systems can be applied specifically to patients with FTC. The distinction of FTC in minimally invasive and widely invasive carcinoma based on the extent of invasiveness rather than vascular invasion is important in identifying low-risk FTC patients for a more conservative management.

A novel microdissection and genotyping of follicular-derived thyroid tumors to predict aggressiveness

Distinguishing thyroid follicular adenoma from minimally invasive or encapsulated angioinvasive carcinoma can be diagnostically challenging. In some cases, tumors are distorted, fragmented, or stripped of their capsule, and a definitive diagnosis becomes nearly impossible. In other cases, the foci of capsular and/or vascular invasion are subtle, thus making the diagnosis of carcinoma difficult. We developed a microdissection genotyping assay for assessing a panel of tumor-suppressor genes for loss of heterozygosity mutations. The frequency of allelic loss (FAL) in follicular-derived neoplasms correlates with the histologic aggressiveness of the tumor. Furthermore, we calculated the amount of genetic heterogeneity within each tumor, as a second important measure of a tumor's ability for clonal expansion and a surrogate marker for its malignant potential. The follicular adenomas had a low FAL (average 9%) and low intratumoral heterogeneity (5% variability). The minimally invasive and encapsulated angioinvasive carcinomas had an intermediate FAL (average 30%) and intermediate intratumoral heterogeneity (10% variability). The widely invasive carcinomas had a high FAL (average 53%) and high intratumoral heterogeneity (24% variability). Although a larger retrospective study is needed to correlate genotyping studies with patient outcome and prognosis, our results indicate that performing a mutational genotyping assay can stratify tumors into the histologically well-defined categories of adenomas, minimally invasive/angioinvasive carcinomas, and widely invasive follicular carcinomas.

A population-based analysis of survival factors in differentiated and medullary thyroid carcinoma

OBJECTIVE

The study purpose was to determine survival and prognostic factors for differentiated thyroid carcinoma (DTC).

METHODS

Cases of DTC were extracted from the Surveillance, Epidemiology and End Results database from 1988 through 1998. Kaplan-Meier survival analysis was conducted for papillary, follicular, and medullary histologies. Cox proportional hazard analysis was used to examine the influence of age, gender, tumor size, local extension, and cervical node involvement on overall survival.

RESULTS

A total of 18,118 cases were identified, including 15,820 (87.3%) papillary carcinomas, 1799 (9.9%) follicular carcinomas, and 499 (2.8%) medullary carcinomas. Mean survival (10-year survival) was 122 (87.7%), 117 (80.2%), and 108 (73.7%) months for papillary, follicular, and medullary tumors, respectively. For each histology, increasing age, male gender, and degree of local extension substantially reduced survival. Cervical metastasis did not influence survival for papillary or follicular carcinomas but approached significance for medullary carcinoma (P = 0.065).

CONCLUSIONS

Degree of local extension in thyroid carcinoma should be subclassified to more accurately determine prognosis. Treatment of the neck should be considered for medullary thyroid carcinoma.