The significance of mitotic rate: a retrospective study of 127 thyroid carcinomas

Clinical and Paraclinical Considerations Regarding ki67's Role in the Management of Differentiated Thyroid Carcinoma-A Literature Review

Background and Objectives: The ki67 nuclear protein is a tool for diagnosis and prognosis in oncology that is used to evaluate cell proliferation. Differentiated thyroid carcinoma is usually a slow-growing neoplasm, the most common type being the papillary form. Some clinical and pathological aspects may predict aggressive behaviour. There are reported cases of recurrence without clinico-pathological findings of aggressiveness. To obtain better predictions of the disease outcome in thyroid carcinoma, many immunohistochemical markers have been studied. The aim of this narrative literature review is to identify the benefits that ki67 may add to the management of patients with differentiated thyroid carcinoma, according to the latest evidence. Materials and Methods: We performed a search on the PubMed and Google Scholar databases using controlled vocabulary and keywords to find the most suitable published articles. A total number of sixty-eight items were identified, and five other articles were selected from other sources. After refining the selection, the inclusion criteria and exclusion criteria were applied, and a total number of twenty-nine articles were included in this literature review. Results and Discussion: The studies consist of retrospective studies (89.66%), case reports (6.9%) and literature reviews (3.45%), evaluating the role, implications and other parameters of ki67 as a diagnostic and/or prognostic tool. The statistical correlations between ki67 and other features were systematized as qualitative results of this review in order to improve the treatment strategies presented in the included articles. Conclusions: The included studies present converging data regarding most of the aspects concerning ki67. The ki67 proliferation index is a diagnostic/prognostic tool of interest in differentiated thyroid carcinoma and a good predictor of disease-free survival, disease recurrence and metastatic development. Prospective studies on large cohorts may add value for ki67 as a specific tool in the management strategy of differentiated thyroid carcinoma.

Low Mitotic Activity in Papillary Thyroid Cancer: A Marker for Aggressive Features and Recurrence

CONTEXT

The significance of low mitotic activity in papillary thyroid cancer (PTC) is largely undefined.

OBJECTIVE

We aimed to determine the behavioral landscape of PTC with low mitotic activity compared to that of no- and high-mitotic activity.

METHODS

A single-institution consecutive series of PTC patients from 2018-2022 was reviewed. Mitotic activity was defined as no mitoses, low (1-2 mitoses/2 mm2) or high (≥3 mitoses/2 mm2) per the World Health Organization. The 2015 American Thyroid Association risk stratification was applied to the cohort, and clinicopathologic features were compared between groups. For patients with ≥6 months follow-up, Cox regression analyses for recurrence were performed.

RESULTS

640 PTCs were included - 515 (80.5%) no mitotic activity, 110 (17.2%) low mitotic activity, and 15 (2.3%) high mitotic activity. Overall, low mitotic activity exhibited rates of clinicopathologic features including vascular invasion, gross extrathyroidal extension, and lymph node metastases in between those of no- and high-mitotic activity. PTCs with low mitotic activity had higher rates of intermediate- and high-risk ATA risk stratification compared to those with no mitotic activity (p < 0.001). Low mitotic activity PTCs also had higher recurrence rates (15.5% vs. 4.5%, p < 0.001). Low mitotic activity was associated with recurrence, independent of the ATA risk stratification (HR 2.96; 95% CI 1.28-6.87, p = 0.01).

CONCLUSIONS

Low mitotic activity is relatively common in PTC and its behavior lies within a spectrum between no- and high-mitotic activity. Given its association with aggressive clinicopathologic features and recurrence, low mitotic activity should be considered when risk stratifying PTC patients for recurrence.

Tumor Microenvironment Features as Predictive Biomarkers in Metastatic Differentiated Thyroid Cancer and Their Relationship With 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT) Metabolic Parameters

OBJECTIVE

The role of the tumor microenvironment in tumor progression and treatment response is being investigated for different types of cancer. This study aimed to determine the relationships between tumor microenvironment, histopathology, 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT)-based metabolic parameters, treatment response, and overall survival (OS) in metastatic differentiated thyroid cancer (DTC).  Methods: Metastatic DTC patients who underwent 18F-FDG PET/CT between 2015-2019 were evaluated. Clinicopathological, histopathological features and PET/CT parameters of patients were recorded. Microenvironmental characteristics of the primary tumor, such as mitosis, intratumoral and peritumoral lymphocytosis, intratumoral and peritumoral fibrosis, were evaluated from the tissue samples. The relationships between these factors were statistically analyzed.

RESULTS

 Sixty-five patients (38 females, 27 males, age: 49±15 years) were included. Mitosis, intra/peritumoral lymphocytosis, and intra/peritumoral fibrosis were frequent; however, none of them had a statistically significant association with PET-positive metastases, treatment response, or OS. Univariate analysis showed that gender, size, thyroglobulin values, residual thyroid tissue, PET-positive metastases, and maximum standardized uptake value (SUVmax) were significant predictors of OS. At multivariate analysis, PET-positive metastases (HR=-2.65, 95%CI 0.007-0.707, p=0.024) and SUVmax (HR=-2.74, 95%CI 0.006-0.687, p=0.023) were the only independent predictors for OS.  Conclusion: Our study revealed that microenvironmental characteristics of the primary tumor did not show prognostic significance in metastatic DTC. PET-positive metastases and SUVmax levels were the only significant factors that predicted overall survival in DTC. Supporting the results of our study with further studies with a larger sample size may be necessary to determine the relationship between the tumor microenvironment and prognosis in DTC.

Rare Clinical Entity: Metastatic malignant struma ovarii diagnosed during pregnancy - Lessons for management

Background

Malignant struma ovarii is an ovarian teratoma containing at least 50% thyroid tissue which has the potential to metastasize and produce thyroid hormone. Given its rarity, management strategies are not well-established. We report a case of metastatic malignant struma ovarii discovered during pregnancy with lessons for evaluation and management.

Case presentation

A 30-year-old woman who was two months pregnant was discovered to have struma ovarii with over half of the struma comprised of papillary thyroid cancer. Following tumor resection, delivery, and thyroidectomy, she underwent evaluation with stimulated thyroglobulin testing and diagnostic staging sodium iodide-131 scan (I-131), which revealed the presence of skeletal metastases. Following administration of 320 mCi I-131, post-therapy scan also showed miliary pulmonary metastases with improved ability to localize the bony and pulmonary metastases with concurrent SPECT/CT imaging. A second dosimetry-guided I-131 therapy resulted in complete resolution of pulmonary metastases; however, small foci of residual bone disease persisted. Post-therapy scans demonstrated additional findings not shown on diagnostic I-131 scans obtained prior to both her initial and second I-131 therapy.

Conclusions

SPECT/CT provides accurate anatomic correlation and localization of metastatic foci and can serve as a baseline study to assess interval response to treatment. Post-therapy scans should always be obtained when I-131 treatment is administered, as additional findings may be revealed versus low dose I-131 activity diagnostic scans. This patient had a high metastatic burden that would not have been discovered in a timely fashion with the conservative approach advocated by others. Thyroidectomy followed by a diagnostic staging radioiodine scan and a stimulated thyroglobulin level should be considered in patients with malignant struma ovarii for guiding therapeutic I-131 administration as metastatic risk is difficult to predict based on histopathologic examination.

Image analysis assisted study of mitotic figures in oral epithelial dysplasia and squamous cell carcinoma using differential stains

BACKGROUND

Mitosis is a process of cell division resulting in two genetically equivalent daughter cells. Excessive proliferation of cells due to mitosis is the hallmark in pre cancer and cancer.

AIMS

This study was conducted to count the number of mitotic figures in normal oral mucosa, oral epithelial dysplasia and squamous cell carcinoma in both Hematoxylin and Eosin (H&E) and Crystal Violet stained sections. Also the overall number of mitotic figures with both stains were compared along with the evaluation of staining efficacy of both the stains.

METHODS AND MATERIAL

The present study was conducted on 20 specimens each of the three categories. These were further divided into two groups for staining with H&E and with 1% Crystal Violet respectively. Images were captured and analyzed using image analysis software Dewinter Biowizard 4.1.

RESULTS

Comparison of mitotic figure count in three categories in sections stained with both stains showed statistically significant difference (p < 0.001). The mean number of mitotic figures seen in Crystal Violet reagent were significantly higher as seen in H&E stain (p < 0.001). The overall diagnostic efficacy of Crystal Violet was 87.6%. Crystal Violet scored over H&E stain and also helped to better appreciate metaphases in Squamous cell carcinoma and telophases in dysplasia.

CONCLUSION

Number of mitotic figures progressively increase with the advancement of the pathology. Use of 1% Crystal Violet provides better appreciation of mitotic figures and can be employed as a selective stain in routine histopathology.

Nuclear markers (star volume, mitotic index, AgNOR and Ki-67) of the primary tumor and its metastasis in non-small cell lung carcinomas

Although tumor growth is controlled by growth rate and cell cycle, it is also likely that the proliferative activity of tumor cells can influence the growth rate of the primary cancer and account for their aggressiveness. Variations in growth rate, cell cycle control and proliferative activity could, in part, explain differences in invasive and metastatic properties among non-small cell lung carcinomas (NSLC). The purpose of this report is to: (1) evaluate growth rate by using growth- and cell cycle-regulating markers (mitotic count, nuclear star volume, AgNOR, and Ki-67) as reflections of growth rate and (2) compare the indices of primary NSLC with the indices of their metastasis in a series of patients with advanced disease. Thirty-three patients with non-small cell lung cancer and hematogenous metastases were retrospectively studied by histochemical, immunohistochemical, and morphometrical investigations. Clinical variables were examined for differences in the frequency of histological subtypes, nuclear star volume, mitotic index, AgNOR area, and Ki-67 immunohistochemistry indices of expression in subgroups of patients stratified by primary tumor and hematogenic metastasis. The impact of these factors on overall follow-up was analyzed. In the samples available in this study, consisting of primary-met paired tumors, which are unique and rarely available for studies of lung cancer, we found that nuclear star volume and mitotic index in metastatic tumors were significantly higher than in the primary tumors. Although there was no significant difference between the Ki-67 index of metastatic and primary tumors, the Ki-67 index in metastatic brain tumors was significantly higher than in the corresponding primary tumors. Examination of Kaplan-Meier survival curves demonstrated that patients with metastatic tumors showing AgNOR area higher than 10.82 microm2 and nuclear star volume lower than 559.50 microm3 had approximately the same odds ratio (log rank of 4.16 and 3.25, p = 0.04 and 0.01, respectively) for survival with a median survival time equal to 17 months for both groups. Analysis of the remaining marker correlation had no impact on survival. We conclude that these results offer future possibilities for more complex studies, including the results of additional immunohistochemical analysis using molecular markers that are known to be important in regulating cell proliferation, e.g., cyclin D1, p27, and cyclin E. These would influence clinical decisions or different therapeutic approaches in advanced stage disease of non-small cell lung cancer.

TGF-β-induced apoptosis in human thyrocytes is mediated by p27kip1 reduction and is overridden in neoplastic thyrocytes by NF-κB activation

Millions of people worldwide suffer goiter, a proliferative disease of the follicular cells of the thyroid that may become neoplastic. Thyroid neoplasms have low proliferative index, low apoptotic index and a high incidence of metastasis. TGF-beta is overexpressed in thyroid follicular tumor cells. To investigate the role of TGF-beta in thyroid tumor progression, we established cultures of human thyrocytes from different proliferative pathologies (Grave's disease, multinodular goiter, follicular adenoma, papillary carcinoma), lymph node metastasis, and a normal thyroid sample. All cultures maintained the thyrocyte phenotype. TGF-beta induced cell-cycle arrest in all cultures, in contrast with results reported for other epithelial tumors. In deprived medium, TGF-beta induced apoptosis in normal thyrocyte cultures and all neoplastic cultures except the metastatic cultures. This apoptosis was mediated by a reduction in p27kip1 levels, inducing cell-cycle initiation. Antisense p27 expression induced apoptosis in the absence of TGF-beta. By contrast, in cells in which p27 was overexpressed, TGF-beta had a survival effect. In growth medium, a net survival effect occurs in neoplastic thyrocytes only, not normal thyrocytes, due to activation of the NF-kappaB survival program. Together, these findings suggest that (a) thyroid neoplasms are due to reduced apoptosis, not increased division, in line with the low proliferative index of these pathologies, and (b) TGF-beta induces apoptosis in normal thyrocytes via p27 reduction, but that in neoplastic thyrocytes this effect is overridden by activation of the NF-kappaB program.

Proliferation Markers and Their Uses in the Study of Endocrine Tumors

A growing body of literature supports the view that the proliferative activity (PA) of tumor cells is an important prognostic indicator for a variety of different tumors. We examined the role of PA in diagnosis and prediction or malignancy of endocrine tumors (ETs) of pituitary gland, pancreas, thyroid, parathyroid glands, adrenal glands, paraganglia, gastroenteric tract, and lung. The data in the literature indicate that the assessment of PA is not a diagnostic indicator of malignancy especially at the individual case level, whereas it can be useful for identifying subsets of malignant tumors with different aggressiveness potential, as well as for choosing therapeutic options in metatstatic lesions. We hope that, in the near future, multiparametric approaches including PA markers, cell growth and differentiation factors, and oncogenes will yield valuable information for diagnosis and prognosis of ETs also in individual cases.

Proliferating cell nuclear antigen (PCNA) in medullary thyroid carcinoma

We investigated the expression of proliferating cell nuclear antigen (PCNA) in paraffin sections from 20 cases of medullary thyroid carcinoma (MTC). Follow-up data were available in eleven cases. PCNA index positively correlated with the degree of cellular pleomorphism (grade) of the tumor (p < 0.01), the pathologic stage (p < 0.01) and the poor clinical outcome (p < 0.05). These findings suggest that PCNA may be of prognostic significance in MTC.

Method for counting mitoses by image processing in Feulgen stained breast cancer sections

This study describes an image processing method for the assessment of the mitotic count in Feulgen-stained breast cancer sections. The segmentation procedure was optimized to eliminate 95-98% of the nonmitoses, whereas 11% of the mitoses did not survive the segmentation procedure. Contour features and optical density measurements of the remaining objects were computed to allow for classification. Twelve specimens were analyzed, nine used to serve as a training set, and three put aside for later use as independent test set. The fully automatic image processing method correctly classified 81% of the mitoses at the specimen level while inserting 30% false positives. The automatic procedure strongly correlated with the interactive counting procedure (r = 0.98). Although the fully automatic method provided satisfactory results, it is not yet suited for clinical practice. The automated method with an interactive evaluation step gave an accurate reflection of the mitotic count showing an almost perfect correlation with the results of the interactive morphometry (r = 0.998). Therefore this semiautomated method may be useful as prescreening device.

Heterogeneity in gastric carcinoma with special reference to DNA content and mitotic activity: histopathologic differentiation

DNA ploidy and mitotic activity were microspectrophotometrically investigated in 46 patients with gastric carcinoma. Measurements of DNA content and mitotic index (M.I.) were examined in the mucosal, submucosal, muscularis propria, and serosal layers of tumors, respectively. The frequency of cells with values exceeding hexaploid chromosome (6c) and mitotic counting analysis revealed a significant higher value in serosa, compared with findings in the mucosa. This tendency was not evident in cases of a differentiated type adenocarcinoma but was noted in those with the undifferentiated type. There were 37 tumors (80.0%) with the same DNA distribution patterns in every layer of the stomach (homogeneous DNA ploidy). Heterogeneity of DNA ploidy was observed in nine tumors (20.0%). Carcinoma with a heterogeneous DNA ploidy manifested a significantly higher incidence of metastasis to the lymph nodes than did those with homogeneous type. Characteristically, there was venous permeation preponderance in the differentiated type and peritoneal dissemination preponderance in the undifferentiated type. This evidence of DNA heterogeneity in gastric carcinoma tissues suggests a possible correlation with the metastatic behavior.

Changes in mitotic rate and cell cycle fractions caused by delayed fixation

The mitosis frequency and flow cytometric data of malignant neoplasms are important, both for diagnosis and for prognosis. It is unclear to what extent these factors are affected by a delay in the fixation of tumor biopsies. We have thus studied the mitotic activity and DNA content in human soft-tissue sarcoma xenotransplants, fixed for periods of 5 minutes and 3, 6, 9 and 12 hours after biopsy. On average, the mitoses counted by two observers were 13% and 10% below initial values after 3 hours, and decreased by 46% and 39% after 12 hours. The mitosis decrease was related to the degree of mitotic activity of individual tumors, and was minimal in the sarcomas with the lowest mitotic rate. These results were reproducible. However, numerous pyknotic mitotic figures were observed, so the decrease in counts is largely due to their reduced identifiability, and only partly attributable to a completion of the cell cycle. Well-preserved mitotic figures demonstrable after 12 hours appear to indicate that the proliferation activity only gradually decreases in unfixed biopsies. The flow cytometric data did not change substantially; only a slight increase in the G2 + M-phase fraction was observed. General conclusions from the results are limited by the fact that the investigated sarcomas had a higher mitotic activity than most carcinomas. Nevertheless, early fixation of biopsies is desirable to accurately measure mitosis counts for the grading of malignancy.

Does delay in fixation affect the number of mitotic figures in processed tissue?

The effect of delay in fixation on the number of mitotic figures in tissues has received little attention, and previous studies have reached differing conclusions. The numbers of mitotic figures in the normal mucosa of six colectomy specimens were counted with delays in fixation of 30 minutes, one hour, two hours, three hours and six hours for samples from each specimen. The numbers of mitotic figures were counted in 50 whole crypts in each specimen by two observers. All phases of mitosis were counted. The number of observable mitotic figures declined by about 30% with a delay in fixation of two hours and by 50% with a delay of six hours. This observation has important implications for the handling of surgical specimens.

Prognostic value of morphometry in papillary thyroid carcinoma

The value of morphometric analysis in addition to standard prognostic indicators was studied in 28 cases of papillary thyroid carcinoma. Standard features included age, sex, lymph node status, tumor size, and encapsulation. The mean follow-up was 47 months (maximum, 140 months). Recurrences were documented in six patients at a mean time of 34 months; five patients recurred with distal metastases and one patient recurred with local disease. Univariate analysis most closely associated tumor recurrence with nuclear anisotropism (the standard deviation of the estimated nuclear area [ENASD]) and tumor size. With forward stepwise incremental analysis, the value of tumor size was lost and only the ENASD and the cellularity mean index (CMI), defined as the percentage of tumor volume composed of tumor cells, significantly correlated with recurrence. Fifty-five percent of patients with an ENASD greater than 17 microns2 and a CMI greater than 40% developed recurrence as compared with 5% of patients with lesser values (P = .0001). Morphometric analysis may significantly contribute to the role of histopathology in the evaluation of papillary thyroid carcinoma and may also provide information regarding prognosis not obtained by standard methods.

Morphometric and morphologic evaluations in stage III non-small cell lung cancers. Prognostic significance of quantitative assessment of infiltrating lymphoid cells

This study evaluated data from 30 non-small cell lung cancer (NSCLC) patients to determine whether demographic, clinical, and morphologic and morphometric data that were obtained prior to treatment, could be used to predict survival. All patients had Stage III disease, and all subsequently were treated identically with concurrent radiotherapy, cisplatin, and 5-fluorouracil. The series consisted of 18 squamous carcinomas, eight adenocarcinomas, and four large cell carcinomas. Morphometric measurements of randomized selected cancer cells per case included diameter of cytoplasm, nuclei, and nucleoli. Morphologic parameters evaluated were mitotic index, histologic differentiation, and pattern of nuclear chromatin of cancer cells, and the degree of necrosis and fibrosis of tumor tissue. The lymphoid and neutrophil index defined as the ratio of lymphoid cells and neutrophils to cancer cells from randomized microscopic fields (median = 25) at 400 x magnification were also determined. Our study indicated that the peritumor lymphoid index was the only factor significantly associated with the length of survival. The correlation coefficient (Pearson r) of these two factors was 0.5 (P less than 0.005). The median survival time of patients with peritumor lymphoid index less than 3 and greater than or equal to 3 was 95 days and 376 days, respectively (Kaplan-Meier estimation). The peritumor lymphoid index was an independent prognosticator of clinical outcome of Stage III NSCLC patients, and did not correlate with any of the other parameters analyzed.

Prognostic factors in medullary thyroid carcinomas. Survival in relation to age, sex, stage, histology, immunocytochemistry, and DNA content

Patients with medullary thyroid carcinomas (MTC) were analyzed according to age, sex, and tumor stage. In addition, the MTC were screened for the predominant histologic pattern, immunocytochemical spectrum (60 tumors), and DNA content (DNA cytophotometry and DNA flow cytometry, 25 tumors). These findings were correlated with follow-up data available for 45 of these patients. Forty-eight percent of the tumors revealed a polygonal cell pattern, whereas 22% showed spindle-cell predominance. All tumors contained cytokeratin, chromogranin A, and calcitonin (CT). Calcitonin gene-related peptide (CGRP) was present in 92%, carcinoembryonic antigen (CEA) in 77%, neuron-specific enolase (NSE) in 75%, and vimentin in 53% of cases. Positivity for neurotensin, somatostatin, neurofilaments, bombesin, and alpha human chorionic gonadotropin (a-hCG) and serotonin ranged between 3% and 27%. All MTC were negative for substance P, adrenocorticotropic hormone (ACTH), thyroglobulin (TG), or S-100 protein. Local recurrences and regional lymph node metastases revealed identical staining patterns as the primaries. Prognosis of MTC was found not to be related to histologic features (dominant architectural pattern, cellular shape, presence of amyloid deposits) or immunocytochemical pattern. Instead, survival was significantly correlated to age, sex, and stage of disease. The best prognosis was seen in women younger than 40 years and revealing an early stage of disease. DNA measurements added valuable information in assessing the prognosis of MTC.

The significance of nuclear diameter in the biologic behavior of thyroid carcinomas: a retrospective study of 127 cases

The relationship between nuclear diameter and biologic behavior was studied in 127 cases of thyroid carcinoma. Using a sonic digitizer coupled to a minicomputer, nuclear diameters of 200 randomly selected cancer cells from each case (hematoxylineosin-stained paraffin sections) projected at X 400 magnification were traced and averaged. A total of 25,400 measurements were made. The nuclear diameters varied from 4.7 to 13.1 micron. By analysis of variance, the nuclear diameters were significantly different (p = 0.0007) among the four types of thyroid cancers, being largest in the undifferentiated cancers (8.7 +/- 0.8 micron) and smallest in the medullary cancers (6.6 +/- 0.1 micron). Nuclear diameter was also significantly correlated with degree of tumor differentiation (p = 0.002), maximal tumor diameter (p = 0.03), mitotic rate (p = 0.002), and 5-year survival (p less than 0.05) for all types of tumors. The correlation between nuclear diameter and disease stage was significant only for undifferentiated cancers (p = 0.04). No significant correlations were seen between nuclear diameter and duration of disease, sex, or age of the patient.