Considerations for personalized surgery in patients with papillary thyroid cancer

Quantitative comparison of three thyroidectomy approaches in neck muscles, voice, and swallowing functions

OBJECTIVE

This study compares endoscopic thyroidectomy by gasless unilateral axillary approach (ETGUA) and sternocleidomastoid leading-edge approach (SLEA) with conventional open thyroidectomy (COT) in hemithyroidectomy. The main focus is on the protection of neck muscles (sternocleidomastoid, omohyoid, sternothyroid) and the postoperative function of voice and swallowing yielded through these common approaches.

METHODS

A total of 302 patients who underwent hemithyroidectomy were enrolled and divided into three groups: ETGUA (n = 101), SLEA (n = 100), and COT (n = 101). Ultrasound was used to measure the thickness of bilateral neck muscles, including the sternocleidomastoid, omohyoid, and sternothyroid. The changes in thickness on the surgical side compared to the non-surgical side. Analyzed factors included muscle thickness changes, Swallowing Impairment Score (SIS), Voice Handicap Index (VHI), Scar Cosmesis Assessment and Rating (SCAR), Neck Injury Index (NII), surgery duration, drainage volume, hospitalization, and number of lymph nodes.

RESULTS

The clinical characteristics among the three groups were consistent except for differences in sex, age, and BMI. Metrics such as sternocleidomastoid muscle, NII, hypocalcemia, postoperative PTH, transient hoarseness, and number of lymph nodes showed no significant differences among the three groups. However, significant differences were found in the duration of surgery, drainage volume, hospitalization period omohyoid muscle, Sternohyoid muscle, VHI, SIS, and SCAR (all p < 0.001).

CONCLUSION

In comparison to COT, ETGUA and SLEA demonstrate superiority in protecting neck muscles and preserving voice and swallowing function without compromising surgical safety or radicality.

Learning curve of trans-areola single-site endoscopic thyroidectomy in a high-volume center: A CUSUM-based assessment

BACKGROUND

Limited attempts have been made in trans-areola single-site endoscopic thyroidectomy (TASSET) due to technical challenges and the lengthy time for proficiency. This study aimed to define the learning curve of TASSET and to describe improvements in operative performance over time.

METHODS

Based on 222 consecutive TASSET procedures, the learning curve was established according to the operation time by using cumulative sum analysis (CUSUM). The end-point of learning curve was defined as the number of cases necessitated to reach the initial surgical proficiency stage. The demographic information, surgical and oncological outcomes, surgical stress, and postoperative complications were also analyzed.

RESULTS

There were 70 cases of simple lobectomy for benign nodules and 152 cases of lobectomy with central neck dissection (CND) for malignancy. The mean operative time was 106.54 ± 38.07 min (range: 46-274 min). The learning curve identified two phases: the skill acquisition phase (Case 1-Case 41) and the proficiency phase (Case 42-Case 222). There were no significant differences in demographic information, drainage amount and duration, oncological outcomes, and postoperative complications between the two phases (p > 0.05). Both operation time and postoperative hospitalization decreased significantly in Phase 2 (154.63 ± 52.21 vs. 95.64 ± 22.96 min, p < 0.001; 4.12 ± 0.93 vs. 3.65 ± 0.63 days, p < 0.001). Additionally, the mean variations of surgical stress factors (C-reactive protein and erythrocyte sedimentation rate) decreased significantly as the phase progress. The case number required for proficiency phase in benign and malignant tumor were 18 and 33, respectively, and lymph node resection posed a significant impact on the endpoint of the learning curve (p < 0.001). Meanwhile, the size of nodule showed no significant impact (p = 0.622). For right-handed surgeons, 16 cases and 25 cases were required for technical competence in left-sided and right-sided lesions, respectively, and no significant difference reached (p = 0.266).

CONCLUSIONS

TASSET has demonstrated safe and technically feasible with comparable oncological outcomes. Experience of 41 cases was required for surgical competence and proficiency. The initial learning stage could be more quickly adopted by high-volume thyroid surgeons with standardized procedures.

Thyroidectomy for thyroid cancer via transareola single-site endoscopic approach: results of a case-match study with large-scale population

BACKGROUND

Due to technical challenges, single-site endoscopic thyroidectomy (SSET) is seldom reported and has been attempted in only limited cases. This large-scale study aimed to compare the clinical outcomes of standardized transareola SSET (TASSET) with those of conventional open thyroidectomy (COT) for thyroid cancer.

METHODS

The data were prospectively collected, and case-match study was performed at a ratio of 1:1 according to age, sex, body mass index, lesion size, number of lesion foci, lesion side, recurrent laryngeal nerve (RLN) exploration and pathology. Two hundred eligible patients underwent TASSET, and the same number of patients was selected for propensity score matching from 2256 patients who underwent COT. Perioperative data, including surgical profile, oncological and traumatic burdens, and cosmetic satisfaction, were analyzed.

RESULTS

No significant differences were observed in blood loss or drainage between TASSET and COT groups. There were no differences in operation time between TASSET and COT (106.39 ± 28.44 vs 102.55 ± 23.10 min, p = 0.154). A total of 3.63 ± 1.82 lymph nodes (LNs) were retrieved from CND with 0.96 ± 1.42 positive in TASSET. In COT, the total and positive LN yields were 3.77 ± 1.91 and 0.99 ± 1.40 (p = 0.445, p = 0.802). Cancer recurrence was not observed in either group. There were no differences in the occurrence of permanent and transient hoarseness or RLN injuries. Postoperative flap seroma or hematoma occurred in 12 TASSET patients and 58 COT patients (p < 0.001). The pain score, CRP level and ESR in TASSET group were lower than those in COT group. TASSET yielded significantly better incision recovery and cosmetic scores than did COT at both the proliferation and stabilization stages.

CONCLUSIONS

TASSET is technically feasible and yields enhanced recovery with minimally invasive and cosmetic advantages without compromising the level of safety or cancer eradication.

Intraoperative carbon nanoparticles mapping in secondary total thyroidectomy for recurrent thyroid nodules: Results of a 8-criterion case-match study (case control study)

BACKGROUND

The extent of total thyroidectomy in the management of multinodular goiter remains unclear. Compared to primary thyroidectomy, secondary total thyroidectomy is more difficult to perform and carries a significantly higher risk of postoperative complications such as recurrent laryngeal nerve (RLN) palsy or hypoparathyroidism. In this study, we aimed to evaluate the efficacy and safety of intraoperative carbon nanoparticle (CN) mapping in patients undergoing secondary total thyroidectomy.

METHODS

We performed a case-matched analysis of a prospectively maintained database using 8 specific criteria to compare perioperative outcomes after primary total thyroidectomy to those after secondary total thyroidectomy with intraoperative CN mapping. The criteria included age, sex, operative procedure, RLN/parathyroid glands (PGs) exploration, preoperative vocal cord calcium abnormalities, and pathological results. Thirty-five patients underwent secondary total thyroidectomy with intraoperative CN mapping due to recurrent thyroid nodules or development of nodules suspicious for malignancy after subtotal thyroidectomy. Fifty exact matches for all 8 criteria were identified from the database in our previous study, which included records of 3078 primary thyroidectomies without CNs. Perioperative outcomes, surgical technique, and complications were analyzed.

RESULTS

The RLNs were successfully identified in all 35 patients. Among three patients that experienced slight hoarseness, one had an RLN end-to-end anastomosis with subsequent improvement in the during the 12-month follow-up period. Two patients experienced changes in vocal tone, but recovered after several months. Two patients underwent parathyroid auto-transplantations, and subsequently presented with transient hypocalcaemia. Their symptoms gradually remitted within one year. Except for mean operation time, there were no statistically significant differences in complications between the primary total thyroidectomies and the secondary total thyroidectomy with CNs.

CONCLUSIONS

Intraoperative CN mapping, expert knowledge of the jugular anatomy, and standardized resection procedures can minimize the incidence of complications such as RLN palsy and hypoparathyroidism after secondary total thyroidectomy.

The impact of electrode resistance on the biogalvanic characterisation technique

Measurement of a tissue-specific electrical resistance may offer a discriminatory metric for evaluation of tissue health during cancer surgery. With a move toward minimally-invasive procedures, applicable contact sensing modalities must be scalable, fast and robust. A passive resistance characterisation method utilising a biogalvanic cell as an intrinsic power source has been proposed as a potentially suitable solution. Previous work has evaluated this system with results showing effective discrimination of tissue type and damage (through electroporation). However, aspects of the biogalvanic cell have been found to influence the characterisation performance, and are not currently accounted for within the system model. In particular, the electrode and salt-bridge resistance are not independently determined, leading to over-predictions of tissue resistivity.

This paper describes a more comprehensive model and characterisation scheme, with electrode parameters and salt-bridge resistivity being evaluated independently. In a generalised form, the presented model illustrates how the relative resistive contributions from the electrodes and medium relate to the existing characterisation method efficacy. We also describe experiments with physiologically relevant salt solutions (1.71, 17.1, 154 mM), used for validation and comparison. The presented model shows improved performance over the current biogalvanic measurement technique at the median conductivity. Both the proposed and extant system models become unable to predict conductivity accurately at high conductivity due to the dominance of the electrodes. The characterisation techniques have also been applied to data collected on freshly excised human colon tissue (healthy and cancerous). The findings suggest that the resistance of the cell under the test conditions is electrode dominated, leading to erroneous tissue resistance determination. Measurement optimisation strategies and the surgical applicability of the biogalvanic technique are discussed in light of these findings.

A novel multiple electrode direct current technique for characterisation of tissue resistance during surgery

Electrochemical and electrical characteristics have the potential to help differentiate between, and assess the health state of, different biological tissues. However, measurement and interpretation of these characteristics is non-trivial. We propose a new DC galvanostatic sensing method for application to laparoscopic cancer surgery. This presents a simple and cost-effective measurement coupled with straightforward data interpretation. This paper describes the electrochemical and electrical theory underpinning the technique. Additionally, we describe a measurement system employing this technique and present an investigation into the feasibility of using it for measuring the resistance of different tissue types. Measurements were performed on ex vivo porcine liver, colon and rectum tissues. Outputs were consistent with theory and showed a significant difference between the resistance of the different tissue types, (one-way ANOVA, F(2, 28) = 1369, p <; 0.01). These findings indicate that this novel technique may be viable as a low cost method for the discrimination and health assessment of tissues in clinical scenarios.

Comparison of conventional thyroidectomy and endoscopic thyroidectomy via axillo-bilateral breast approach in papillary thyroid carcinoma patients

BACKGROUND

Endoscopic thyroidectomy has been applied to solve the cosmetic problems that resulted from conventional thyroidectomy. The aim of this study was to evaluate and compare the surgical outcomes of conventional and endoscopic thyroidectomies via axillo-bilateral-breast approach (ABBA) in patients with papillary thyroid carcinoma (PTC).

METHODS

Between May 2007 and February 2011, 1003 patients with PTC underwent thyroidectomies. The eight hundred and thirty patients underwent conventional thyroidectomy and 173 patients underwent endoscopic thyroidectomy via ABBA. Clinicopathologic characteristics, complications, and surgical completeness were analyzed.

RESULTS

The mean age was 49.53 years who received a conventional thyroidectomy and 38.90 years in endoscopic thyroidectomy (P < 0.0001). The conventional thyroidectomy group underwent more extensive surgery than the endoscopic thyroidectomy group but the operation time was longer in the endoscopic thyroidectomy group (P < 0.0001). The mean hospitalization length was 6.98 days following open thyroidectomy and 6.40 days after endoscopic thyroidectomy (P = 0.003). The tumor size was larger in the conventional thyroidectomy group than the endoscopic thyroidectomy group and a lesser number of lymph nodes were retrieved in the endoscopic thyroidectomy group compared to the conventional thyroidectomy group (P < 0.0001). The postoperative complications and thyroglobulin levels in both groups were not significantly different.

CONCLUSION

These results suggest that conventional and endoscopic thyroidectomy via ABBA has similar surgical outcomes in PTC patients. Therefore, endoscopic thyroidectomy via ABBA may be an appropriate surgical alternative to conventional thyroidectomy for treating PTC in selected patients.

A time-dependent model for improved biogalvanic tissue characterisation

Measurement of the passive electrical resistance of biological tissues through biogalvanic characterisation has been proposed as a simple means of distinguishing healthy from diseased tissue. This method has the potential to provide valuable real-time information when integrated into surgical tools. Characterised tissue resistance values have been shown to be particularly sensitive to external load switching direction and rate, bringing into question the stability and efficacy of the technique. These errors are due to transient variations observed in measurement data that are not accounted for in current electrical models. The presented research proposes the addition of a time-dependent element to the characterisation model to account for losses associated with this transient behaviour. Influence of switching rate has been examined, with the inclusion of transient elements improving the repeatability of the characterised tissue resistance. Application of this model to repeat biogalvanic measurements on a single ex vivo human colon tissue sample with healthy and cancerous (adenocarcinoma) regions showed a statistically significant difference (p < 0.05) between tissue types. In contrast, an insignificant difference (p > 0.05) between tissue types was found when measurements were subjected to the current model, suggesting that the proposed model may allow for improved biogalvanic tissue characterisation.

A survey of preferences regarding surgical approach to thyroid surgery

BACKGROUND

Transaxillary thyroidectomy (TAT) has gained popularity in East Asian countries; however, to date there have been no attempts to evaluate the preferences regarding TAT in the US population. The aim of this study is to assess the preferences and considerations associated with TAT in an American cohort.

METHODS

Self-administered surveys were distributed to 966 adults at various locations in a single state. Questions assessed preferences for the surgical approach, acceptable risks and extra costs, and willingness to pursue TAT despite reduced cancer treatment efficacy.

RESULTS

The response rate was 84 %, with a mean age of 40 ± 17 years. The majority of respondents were female. Of the respondents, 82 % preferred TAT to a cervical thyroidectomy (CerT), all risks being equal; 51 % of the respondents were willing to accept a 4 % complication rate with TAT, and 16 % stated they would agree to pay up to an additional $US5,000 for the TAT approach. When presented with thyroid cancer, 20 % of all respondents still preferred TAT, even if it would not cure their disease. Patients preferring TAT over CerT were younger, female, more willing to accept complications and spend additional money, and, most significantly, preferred the TAT approach, even if it was less likely to cure their cancer.

CONCLUSIONS

Although this survey presents a hypothetical question for people who do not have thyroid disease, the majority of respondents preferred TAT over CerT. Furthermore, a substantial number were willing to accept higher complication rates and increased costs for TAT.

A preoperative nomogram for the prediction of ipsilateral central compartment lymph node metastases in papillary thyroid cancer

BACKGROUND

Central compartment lymph node metastases in papillary thyroid carcinoma (PTC) are difficult to detect preoperatively, and the role of routine or prophylactic central compartment lymph node dissection (CLND) in managing PTC remains controversial. The aim of this project was to create a nomogram able to predict the occurrence of central compartment lymph node metastasis using readily available preoperative clinical characteristics.

METHODS

Records from patients undergoing total thyroidectomy and lymph node dissection for PTC in the period 1968-2012 were analyzed. Nodal status was based on results of serial hematoxylin and eosin (H&E) examination. Age, sex, tumor size, tumor site, and multifocality were included in a multivariable logistic regression model to predict lymph node metastasis. A coefficient-based nomogram was developed and validated using an external patient cohort.

RESULTS

The study population included 914 patients (80% females) with an average central compartment nodal yield of eight per patient. Central compartment lymph node metastases were present in 390 patients (42.7%). The variables with the strongest predictive value were age (p<0.001), male sex (p<0.001), increasing tumor size (p<0.001), and tumor multifocality (p<0.05). The nomogram had good discrimination with a concordance index of 76.4% [95% confidence interval 73.3-79.4], supported by an external validation point estimate of 61.5% [95% confidence interval 49.5-73.6]. An online calculator and smartphone application were developed for point of care use.

CONCLUSIONS

A validated nomogram utilizing readily available preoperative variables has been developed to give a predicted probability of central lymph node metastases in patients presenting with PTC. This nomogram may help guide surgical decision making in PTC.

BRAF mutation in papillary thyroid cancer and its value in tailoring initial treatment: a systematic review and meta-analysis

Clinicians have long sought to characterize biological markers of neoplasia as objective indicators of tumor presence, pathogenicity, and prognosis. Armed with data that correlate biomarker activity with disease presence and progression, clinicians can develop treatment strategies that address risks of disease recurrence or persistence and progression. The B-type Raf kinase (BRAF V600E) mutation in exon 15 of the BRAF gene has been noted to be a putative prognostic marker of the most prevalent form of thyroid cancer, papillary thyroid cancer (PTC)--a tumor type with high proclivity for recurrence or persistence. There has been a remarkable interest in determining the association of BRAF mutation with PTC recurrence or persistence. Using many new studies that have been published recently, we performed a meta-analysis to investigate correlations of BRAF mutation status with PTC prognosis, focusing on the recurrence or persistence of the disease after initial treatment. The study was based on published studies included in the PubMed and Embase databases addressing the BRAF mutation and the frequency of recurrence of PTC. We selected studies with data that enabled measurement of the risk ratio for recurrent disease. We also analyzed the factors that are classically known to be associated with recurrence. These factors included lymph node metastasis, extrathyroidal extension, distant metastasis, and American Joint Committee on Cancer (AJCC) stages III/IV. We used 14 articles that included an analysis of these factors as well as PTC recurrence data, with a total of 2470 patients from 9 different countries. The overall prevalence of the BRAF mutation was 45%. The risk ratios in BRAF mutation-positive patients were 1.93 (95% confidence interval [CI], 1.61-2.32; Z = 7.01; p < 0.00001) for PTC recurrence, 1.32 (95% CI, 1.20-1.45; Z = 5.73; p < 0.00001) for lymph node metastasis, 1.71 (95% CI, 1.50-1.94; Z = 8.09; p < 0.00001) for extrathyroidal extension, 0.95 (95% CI, 0.63-1.44; Z = 0.23; p = 0.82) for distant metastasis, and 1.70 (95% CI, 1.45-1.99; Z = 6.46; p < 0.00001) for advanced stage AJCC III/IV. Thus, in this meta-analysis, the BRAF mutation in PTC was significantly associated with PTC recurrence, lymph node metastasis, extrathyroidal extension, and advanced stage AJCC III/IV. Patients with PTC harboring mutated BRAF are likely to demonstrate factors that are associated with an increased risk for recurrence of the disease, offering new prospects for optimizing and tailoring initial treatment strategies to prevent recurrence.

The molecular diagnosis and management of thyroid neoplasms

PURPOSE OF REVIEW

The molecular work-up of thyroid nodules on fine needle aspiration (FNA) cytology samples has given clinicians a new level of diagnostic information. We focus this review on the molecular techniques used in the diagnosis of thyroid cancer, especially BRAF, and the resulting management considerations that are raised.

RECENT FINDINGS

BRAF testing offers both diagnostic and prognostic information; it has been used along with the Bethesda Thyroid FNA Classification System to offer preoperative guidance in the management of thyroid nodules. Various authors have successfully utilized molecular panels on cytologic specimens including mutations and rearrangements such as RAS and RET/PTC. Preoperative mutation detection allows initial management decisions to be made with a greater clinical confidence.

SUMMARY

BRAF molecular testing holds promise as a possible diagnostic tool for indeterminate FNAs, and as a determinant for planning initial clinical management of thyroid nodules. Further developments in the molecular approach to thyroid cancer are expected to allow greater individualization of patient care.