"Occult" papillary carcinoma of the thyroid: a questionable entity

Surgical management of thyroid cancer

Thyroid cancer is the most common endocrine neoplasm; however, it only accounts for less than 1% of all human malignances. Thyroid cancers are divided into well differentiated and non-well differentiated cancers, according to their histology and behavior. The surgical management options of well-differentiated thyroid cancer include total or near-total thyroidectomy, subtotal thyroidectomy and lobectomy plus isthmusectomy. The extent of surgery for thyroid cancer continues to be an area of controversy. Complications associated with thyroid surgery are directly proportional to the extent of thyroidectomy and inversely proportional to the experience of the operating surgeon. They occur less frequently with good surgical technique and better understanding of surgical anatomy, and include wound healing and infections (seroma, hematoma and wound infection), nerve injury, hypoparathyroidism, hypothyroidism, postoperative hemorrhage and respiratory obstruction.

Total versus hemithyroidectomy for microscopic papillary thyroid cancer

BACKGROUND

No increased mortality has been reported in patients with thyroid papillary microcarcinoma (PMC); however, neck recurrences and distant metastases have been described. In this study, we compare patients' outcomes after total thyroidectomy vs hemithyroidectomy for treatment of thyroid PMC.

METHODS

Two hundred and ninety-three patients from two major medical centers in Israel were included. The mean follow-up period was 7.2±6.8 yr.

RESULTS

Total thyroidectomy was performed in 214 patients and hemithyroidectomy in 79 patients. Mean tumor size was 6.3±3 mm. Lymph-node (LN) metastases and extraglandular extension were more frequent in the total thyroidectomy group than in the hemithyroidectomy group, 24.8% vs 1.3% (p<0.001) and 11.7% vs 3.8% (p=0.042), respectively. The cumulative incidence of recurrence at the end of follow-up was 13.2% in the total thyroidectomy group and 14.3% in the hemithyroidectomy group (p=ns). The incidence of recurrence was higher in patients with LN involvement in both groups. Considering low risk patients only (monofocal tumors, no LN involvement, no extraglandular extension; no.=63 in the total thyroidectomy group vs no.=60 in the hemithyroidectomy group) neck recurrence was found in 10% of patients in the hemithyroidectomy group but none in the total thyroidectomy group. In the hemithyroidectomy group, all locoregional recurrences were diagnosed using ultrasonography, compared to 47.6% in the total thyroidectomy group.

CONCLUSION

For patients with monofocal disease within the thyroid gland and no LN involvement, hemithyroidectomy can be considered an option, bearing in mind a higher risk for recurrence. For all other patients with PMC, we propose total thyroidectomy as initial treatment.

Papillary microcarcinoma

Background

Papillary microcarcinoma (PMC) is increasing in incidence because of diagnosis by ultrasound-guided fine-needle aspiration cytology.

Methods

Between January 1966 and December 1995, we treated 6019 patients with papillary cancer; among them, 2070 patients with PMC were studied.

Results

PMC is essentially very similar to papillary cancer that is 11 mm or larger and has a very good prognosis. Smaller tumors and younger patients have a better prognosis. Among PMC, larger tumors (6–10 mm) recur in 14% at 35 years compared with 3.3% in patients with smaller tumors. Patients older than 55 years have recurrence in 40% at 30 years, with a worse prognosis than younger patients who have a recurrence rate of less than 10%. Extracapsular invasion by the primary tumor also has a higher recurrence rate. The majority of recurrences are in the neck. Therefore, annual ultrasound of the neck is effective for recurrence surveillance.

Conclusion

Papillary microcarcinoma is similar to larger papillary carcinomas with tumor characteristics and age-based recurrence rate that extends for many years, justifying long surveillance after surgery.

A review of 227 cases of small papillary thyroid carcinoma

AIMS

To review differences in biological aggressiveness, clinical behaviors or selected surgical treatments between the PMC and the slightly larger PTC of 1.0<T<or=2.0 cm.

METHODS

Two hundred and twenty-seven cases of papillary thyroid carcinoma not larger than 2.0 cm, diagnosed and treated at the Kuma Hospital, Kobe, Japan, with a 10-year follow-up from 1992 to 2003, were reviewed.

RESULTS

The small PTCs demonstrated excellent outcomes, and persistent/recurrent disease was identified in only nine patients (4%). None of the patients died of the disease. A multivariate analysis revealed that massive extrathyroidal extension at presentation was the only independent prognostic factor for locoregional recurrence. Subdivision into PMCs and slightly larger tumors (1<T<or=2 cm) did not affect the excellent outcomes, but the patients in the latter subgroup received more lymph node surgery and displayed more aggressive clinico-histological features such as higher rates of extrathyroidal extension, lymph node metastasis, loss of polarity, invasive growth pattern and loss of cohesiveness.

CONCLUSIONS

Small PTC not larger than 2.0 cm could be considered as favorable a prognosis as PMC.

Papillary microcarcinomas of the thyroid gland and immunohistochemical analysis of expression of p53 protein in papillary microcarcinomas

Background

Thyroid papillary microcarcinoma (TPM) is defined according to WHO criteria as a thyroid tumor smaller than 1–1.5 cm. TPMs are encountered in 0.5–35.6 % of autopsies or surgical specimens where carcinoma had been unsuspected. The purpose of the present study was to evaluate patients who had TPMs in terms of clinical findings, histopathological features and immunohistochemical evidence of expression of the tumor suppressor gene p53.

Methods

A total of 44 patients with TPMs less than 1.0 cm in diameter were included in the study. The patients were evaluated clinically and the tumors were evaluated in terms of their histopathological and immunohistochemical features, including expression of p53.

Results

The female/male ratio was 2.8/1, and the median age at time of diagnosis was 49 years (range 20–71 years). The maximum diameter of the smallest focus was 0.1 mm, and that of the largest was 10 mm microscopically. The mean diameter of all tumors was 5.7 mm. There was no correlation between tumor size and age or gender. Of the TPMs, 72 % were found in the right lobe, 24 % in the left lobe and 4 % in the isthmus. Fine-needle aspiration biopsy provided the diagnosis of TPM in only 43.2 % of the patients. All patients were treated with surgery, with 20 undergoing conservative surgery, i.e. lobectomy or isthmusectomy, and 24 undergoing total thyroidectomy. Frozen section provided the diagnosis of TPM in only 56.8 % of the patients. We found lymphocytic thyroiditis in 13.6% of patients, follicular variants in 11.9%, capsular invasion in 26.8%, lymph node involvement in 11.9%, soft tissue metastases in the neck in 12.1% and multifocality in 31.7 %, and none of these were related to age or gender (p > 0.05). No distant metastases were observed during approximately 10 years of follow up. We found p53 positivity in 34.5 % of TPM tumors. However, p53 expression was not statistically related to age or gender.

Conclusion

Our findings imply that TPMs may not be entirely innocent since they are associated with signs of poor prognosis such as capsular invasion, multifocal presentation, lymph node involvement and p53 positivity. Therefore, TPMs should be evaluated and followed like classical papillary cancers.

Papillary thyroid microcarcinoma: A surgical perspective

Papillary thyroid microcarcinoma (PTMC) is defined as a papillary thyroid cancer measuring less than 10mm in its greatest diameter. It is the most common form of thyroid cancer, detected in up to 36% in autopsy studies. The wide availability and use of neck ultrasonography in the evaluation of carotid arteries and of the thyroid resulted in an increased detection of PTMC. PTMC is often multifocal. The diagnosis is usually based on a combination of clinical examination, laboratory investigations, and specialized radiological techniques (mainly neck ultrasonography combined with fine-needle aspiration cytology). A common scenario is the diagnosis of PTMC as an incidental finding following thyroidectomy for a presumably benign thyroid disease. Despite some controversy, most authors agree that PTMC should be treated by total or near-total thyroidectomy, provided it can be performed safely. Because of its many and major advantages, in our clinical practice, total or near-total thyroidectomy is the procedure of choice for the management of PTMC. Given the high incidence of PTMC as an incidental finding and the frequent multi-focality, we also favor total or near-total thyroidectomy for the surgical management of nodular thyroid disease (multinodular goiter or dominant presumably benign thyroid nodule/s). Despite some controversy, we perform central neck lymph node dissection electively, in the presence of cervical lymphadenopathy. Radioiodine ablation therapy may be used as an adjuvant therapy. Prognostic factors (such as tumor multicentricity, positive lymph nodes, capsular or vascular invasion) or scoring systems (such as the AMES) can be used to select patients for radioiodine adjuvant therapy. Suppression therapy is needed after surgical management. Despite the potential for neck lymph node and even distant metastases, the biological behavior of PTMC is in general benign and the prognosis is very good.

Thyroid microcarcinoma: prevalence, prognosis, and management

OBJECTIVE

To review the usual course of thyroid microcarcinoma (TMC) and the associated prognosis and treatment of affected patients.

METHODS

We discuss predisposing factors in the formation of TMC and the modulation of its behavior, diagnostic evaluation, and management options.

RESULTS

TMC, generally defined as a well-differentiated thyroid cancer less than or equal to 15 mm in diameter, has an estimated prevalence (based on autopsy studies) of about 5 to 10%. Studies, however, have shown that most of these cancers are smaller than 5 mm in diameter. The high prevalence of TMC in the general population contrasts with the rarity of thyroid cancers of greater size, which constitute less than 1% of malignant neoplasms in the United States. The frequent detection of TMC as a result of routine imaging of the neck for unrelated reasons and as a incidental finding in surgical specimens has raised a question about whether the management of TMC should differ from that for thyroid cancer of appreciable size. The uncertainty about optimal management of TMC is attributable to the small number of long-term follow-up studies as well as the common observation that patients usually have an excellent prognosis. Although in most patients harboring a TMC the cancer remains quiescent and never becomes clinically significant, in some cases TMC can demonstrate an aggressive course. Several variables, such as older age, multifocality, bilateral disease, and extrathyroidal spread at initial assessment, may have some adverse prognostic significance. After a partial surgical removal of the thyroid gland for TMC, the recurrence rate may be as high as 11%. Therefore, a treatment dilemma is caused by the low propensity of TMC for progression to clinically significant disease, yet the potential for recurrence and aggressive behavior in some cases.

CONCLUSION

In general, surgical resection of TMC is based on results of fine-needle aspiration biopsy and the rate of growth of the nodule. Aggressive management seems indicated in high-risk patients, particularly older patients, those with a history of radiation exposure, and those with multifocal disease, bilateral disease, or lymph node involvement.

[Relation between clinical presentation and prognosis of patients with papillary thyroid microcarcinoma]

BACKGROUND AND OBJECTIVE

We aimed to analyze patients with papillary thyroid microcarcinoma (PTM) in order to establish the prognosis according to the differences observed between those diagnosed before surgery and those diagnosed postoperatively.

PATIENTS AND METHOD

Retrospective study of 83 PTM patients who were distributed in 2 groups. Clinical, histological and follow-up data were compared. Survival and disease-free interval (DFI) were analyzed in both groups.

RESULTS

Group A (diagnosed before surgery): 30 patients (36.1%); group B (diagnosed postoperatively): 53 patients (63.9%). Five group A patients had a relapse. Overall survival was 98.8% and overall DFI was 94% (83.3% in group A and 100% in group B, p = 0.01).

CONCLUSIONS

It is useful to differentiate patients with PTM diagnosed before surgery from those whose PTM was diagnosed after since their evolution is different.

Microcarcinoma of the thyroid gland: the Gustave-Roussy Institute experience

BACKGROUND

Patients with thyroid microcarcinoma (TMC) have favorable long term prognoses. However, recurrences in the neck and distant metastases have been reported. The authors investigated independent factors associated with recurrence in an effort to define therapeutic guidelines.

METHODS

Two hundred eighty-one patients (207 females, 74 males; mean age, 41.9 years) with a differentiated thyroid carcinoma < or = 1 cm in greatest dimension (mean size +/- standard deviation, 5.9+/-3.3 mm) were analyzed. The median follow-up time was 7.3 years.

RESULTS

TMC diagnosis was incidental in 189 patients, and metastases were the first manifestation of the disease in the other 92 patients. Therapy included near-total thyroidectomy for 195 patients, lymph node dissection for 195, and therapeutic administration of radioiodine for 124. Eleven recurrences (3.9%) were observed 4.3+/-2.7 years (mean +/- standard deviation) after initial treatment: all had locoregional recurrence (4 in the thyroid bed and 7 in the lymph nodes), and in one of these the local recurrence was associated with lung metastases. Multivariate analysis showed that two parameters significantly influenced TMC recurrence, namely, the number of histologic foci (P < 0.002) and the extent of initial thyroid surgery (P < 0.01). Only 3.3% of patients with unifocal TMC treated with loboisthmusectomy had tumor recurrence.

CONCLUSIONS

The recurrence rate for TMC appears to be low (3.9%). In the authors' view, loboisthmusectomy is the treatment of choice for patients with TMC when only one focus of cancer is found histologically, and total thyroidectomy is the optimal treatment for patients with multiple foci.

Therapeutic strategies and long-term results in differentiated thyroid cancer

Differentiated thyroid carcinoma (DTC) is usually an indolent tumor associated with a low mortality. However, DTC, particularly papillary thyroid carcinoma, happens to be a multicentric tumor and tends to spread to the regional lymph nodes in the early stage of the disease; some patients with DTC do die from metastatic or recurrent disease. Despite the small number of these patients, therapeutic strategies designed to prevent such outcomes should be pursued. In this review, we attempt to evaluate the impact of different therapeutic strategies on survival and recurrence. Consequently, we conclude that the surgical approach to DIC should be individualized on the basis of the biologic behavior of the tumor, rather than on the extent of cancer involvement in the thyroid and regional lymph nodes. It is mandatory to expand our efforts to identify high-risk patients more accurately, thereby facilitating more rational approaches to treatment.

Papillary microcarcinoma of the thyroid gland

Papillary microcarcinomas are a specific subgroup of papillary thyroid cancer. They have the same histological features as papillary thyroid cancer but are 1.0 cm or less in diameter. These tumours are a common incidental finding at autopsy and in thyroid glands excised for other pathology. This tumour can metastasize to regional lymph nodes but its ability to cause significant morbidity and mortality has been questioned. As papillary microcarcinomas can represent up to 30 per cent of all papillary cancers seen in a thyroid surgeon's practice, they are an important group. The aim of this review article is to outline the natural history of papillary microcarcinoma and to offer therapeutic management strategies.

Highly aggressive behaviour of occult papillary thyroid carcinoma

Occult papillary thyroid carcinoma is generally associated with an excellent prognosis. Distant metastasis of this tumour is extremely rare. A case of occult papillary thyroid carcinoma with metastases to the lungs, cervical lymph nodes, skeleton, and the brain is reported. The tumour expressed itself in extremely aggressive clinical behaviour and responded only partially to aggressive therapy. The controversial methods of treatment for occult papillary thyroid carcinoma are also discussed.