Bibliometrics is a rapidly advancing field that promises to incorporate an objective element into a long-standing process of measuring scholarly impact. The availability of electronic databases and downloadable tools to aid these calculations will likely increase their use and add an objective measure to the subjective letter of reference [10] [11]. In this study, we used visualization software to explore research trends and hotspots among papers in the field of PTC surgical procedures published from 1990–2021, which is very helpful in predicting the next research direction for investigators of PTC surgical procedures [12] [13].
Our findings revealed that the number of publications and citations displayed an increasing trend from 1990–2021, with 2022 likely to be the year with the highest growth rate of publications and the highest number of citations. This implies that this area of research may remain relevant in the coming years. In the past decade, PTC has been one of the fastest-growing cancers in terms of incidence rate [2] [14] [15]. The dominant role of thyroidectomy in the treatment of PTC is unquestionable and, as the incidence of PTC has risen, thyroidectomy procedures have also increased [16].
An analysis of published journals can help scholars to select appropriate journals when reading literature or submitting articles. The top 11 journals (two journals tied for fourth, two tied for sixth, and two tied for ninth) published a total of 6–24 articles per journal. Thyroid was the most productive journal. In 2020, three of the 11 active journals had IFs of > 5 and eight had IFs of > 3. Notably, the average citation rate of these journal publications was higher than the IF of the journal in 2020. This indicates that PTC surgical procedures are an emerging and hot area of research that may align with patient needs, and these publications are likely to be cited more in the coming years. The thematic journals can be divided into five categories (endocrinology and metabolism; surgery; oncology; otorhinolaryngology; and radiology, nuclear medicine, and medical imaging), showing that PTC surgery is a discipline that requires multidisciplinary involvement [17].
We found that the United States, Italy, and South Korea dominated in terms of the number of publications, h-index values, and total citations for PTC surgery. We discovered that, among the top six most-productive institutions, almost 50% were in South Korea, suggesting the high quality of articles published by South Korean institutions. The most prolific institution was Yonsei University in Korea, and three of the top five authors in terms of publication numbers were from this institution, so it can be considered an influential institution for the purpose of collaboration. Woong Youn Chung from Yonsei University and Hoon Yub Kim from Korea University each had the most publications (n = 9), and Jong Ju Jeong and Kee-Hyun Nam from Yonsei University each had the top AC (72.38). Our analysis reveals that these authors have published many publications and collaborated closely, so they could be regarded as leaders in this professional research field.
Citation analysis provides us with a new angle to detect the influence of some documents on a certain topic. As we can see, the top 10 references with the strongest citation bursts seemed to be concerned with the extent of surgery, differential diagnosis, lymph node invasion, novel surgical approaches, overtreatment issues, and active surveillance [8, 9, 18–25]. Adequate surgery is the most important prognostic determinant in the management of PTC. At the same time, other treatment variables, including radioiodine ablation and thyroid-stimulating hormone–suppression therapies, may serve as adjuncts in some patients [9]. Recurrence is a critical issue when it comes to patient prognosis after thyroid surgery. A modified initial risk-stratification system was proposed in the 2015 American Thyroid Association guidelines and depicted the risk of recurrence in differentiated thyroid carcinoma patients after initial therapy [8]. Furthermore, multiple treatments are also used to inhibit tumor recurrence, including thyroid-stimulating hormone–suppression therapy and radioactive iodine therapy [26]. Another hot topic in PTC treatment is lymph node invasion, as lymph node metastases are reported in up to 50% of patients with PTC [27]. Lymph node invasion is proven to be associated with a higher recurrence rate and poorer survival data [28]. While lymphadenectomy is necessary in patients detected with suspicious lymph node invasion, the role of prophylactic central compartment neck dissection remains controversial, mainly because of the unclear long-term outcomes of this procedure [24] [29]. In addition, novel surgical approaches, including intraoperative nerve monitoring and transoral and robotic approaches, have been refined in recent years [19, 21, 22]. The study by Nikiforov et al. [18] specifically raised the issue of overtreatment and active surveillance, and their study suggests that a large proportion of PTC do not require surgical intervention. However, the problem lies primarily in effectively differentiating patients who need immediate surgery and using uniform criteria to recommend surgery for different patients with progressive lesions. We need large, high-quality randomized controlled trials to help us address this issue, and we are fortunate that data from ongoing trials will be available in the next few years.
Statistics and analysis of the co-occurrence of words in scientific publications can provide an intuitive picture of the veritable content of our study. In the thyroid nodule field, the most crucial task is to distinguish between benign and malignant nodules [30, 31]. Although PTC is regarded as an indolent tumor, a portion of cancer cells will metastasize to lymph nodes around the thyroid gland [8], mainly including central lymph node metastasis (LNM) and lateral cervical LNM [32]. Usually, LNM occurs first in the central region, followed by the lateral region. LNM is an important indicator of PTC prognosis, scope, and method of surgery, and is also an important risk factor for a high recurrence rate and low survival rate of patients [33] [34]. Ultrasound-guided fine-needle aspiration biopsy is simple, safe, and reliable, providing the most definitive information for differential diagnosis. In most of the medical centers in the world, cytology results from ultrasound-guided fine-needle aspiration biopsy are reported according to six categories of the 2017 updated Bethesda classification system [35]. However, 20–30% of patients will receive indeterminate results, requiring additional evaluations [36] [37]. As a novel diagnostic method, genomic analysis, including microRNA analysis, holds great potential in contributing to the differential diagnosis [38] [39]; as such, future diagnostic systems should consider genomic analysis.
The surgical management of PTC remains contentious; the extent of thyroid resection has been the nub of this debate. The literature lacks prospective randomized controlled trials that could help put this debate to rest. Consequently, large retrospective studies and expert opinion have constituted the basis of clinical practice guidelines. Recent American Thyroid Association and National Comprehensive Cancer Network guidelines [8, 20, 40] consider a conservative approach in the form of a thyroid lobectomy sufficient for low-risk disease, while total thyroidectomy remains the standard of care in the presence of high-risk features. Nevertheless, many authorities still advocate for more aggressive therapy in low-risk cases. From the current literature, there is no single surgical strategy that meets all requirements. The extent of thyroidectomy should be carefully decided based on preoperative, intraoperative, and postoperative prognostic characteristics and risk group analysis to maintain an acceptable low risk of recurrence.
There were some limitations in this study. First, only SCI-E was chosen for the bibliometric search because of its high-quality and comprehensive number of publications, although other databases are also available for review. Second, some publications were tagged as multiple publication types. Although the publication type was manually adjusted with double-checking, this might still cause inaccuracy. The use of SCI-E might also bring some bias by over-representing papers published in English.