Introduction

Currently, the world population is growing by 1.18% per year, or approximately an additional 83 million people annually. The world population is projected to increase by more than one billion people within the next 15 years, reaching 8.5 billion in 2030, and to increase further to 9.7 billion in 2050 and 11.2 billion by 2100 [1]. During 2015–2050, half of the world’s population growth is expected to be concentrated in nine countries: India, Nigeria, Pakistan, Democratic Republic of the Congo, Ethiopia, United Republic of Tanzania, United States of America (USA), Indonesia and Uganda, listed according to the size of their contribution to the total growth [1]. All of them are low- and middle-income countries (LMICs) except the USA. As recently reported by the Lancet Global Surgery 2030 commission, ‘Treatment for surgical conditions, a broad range of diseases that represent approximately 30% of the global burden of disease and span 100% of disease sub-categories, remains out of reach for the majority of the world’s population. Surgery is essential for global cancer care in all resource settings. Of the 15.2 million new cases of cancer in 2015, over 80% will need surgery, some several times. By 2030, we estimate that 45 million surgical procedures will be needed worldwide. Yet, less than 25% of patients with cancer worldwide actually get safe, affordable, or timely surgery’ [2]. The rate of incidence of thyroid cancer has increased more than any other cancer worldwide [3, 4]. The USA has seen a > 300% increase in the prevalence of thyroid cancer within the past 30 years [4] and few estimates suggest that thyroid cancer could become the third most common cancer to be diagnosed in women by 2019 [5]. As the global surgical burden is increasing, there is a steady increase in demand of surgeons trained in endocrine surgery. Further, there is ample literature highlighting the relationship between surgeon volume and outcomes in complex and/or uncommon procedures [6, 7]. Wiseman et al. [8] have reported that addition of a dedicated endocrine surgery programme at their institution positively influenced the quality of resident education in the surgical management of endocrine diseases in four measures: operative exposure, self-assessed knowledge, overall rotation experience and academic productivity. Despite this, there are few dedicated surgeons and centres in this field even in the developed world as compared to other surgical disciplines like surgical gastroenterology, surgical oncology, cardiovascular and thoracic surgery and plastic surgery. Formal training in endocrine surgery is available at only a handful of institutions worldwide, and no fellowship positions are available for surgeons from the developing world except very few.

Evolution of endocrine surgery in India is the comparatively latest phenomenon as compared with other surgical sub-specialties. Approximately three decades back, the first academic department was started in our country and even after three decades, there are only four institutes which provide training in this field which is accredited by the Medical Council of India. Initial slow pace has gained momentum in the past few years with increasing presence of trained endocrine surgeons in major cities of India, peer-reviewed research publications and academic programmes. However, the majority of endocrine operations especially thyroid surgeries are being performed by general surgeons, head and neck surgeons and surgical oncologists.

After three decades of the establishment of the first academic department, there was a need to carry out a survey of the global and Indian scenario with a special emphasis on the impact of this dedicated endocrine surgery training programme on academic activities and research and development of new departments in India.

Methods

Search Strategy

Single repository or one all-inclusive website providing information on endocrine surgery training for all countries does not exist. Hence, multiple sources were used to develop an understanding of the training and certification of endocrine surgeons globally. We searched Medline, EMBASE and the Global Health Library databases with the search terms ‘endocrine surgical training’ and ‘endocrine surgery fellowship’ for abstracts and citations in all languages published between January 1, 1979, and December 31, 2016, describing a national endocrine surgery training system. Synonyms for surgical trainees, such as resident, chief resident and registrar, were used in addition to alternative names for training programmes (for example, surgical training, residency training and specialty training). Terminologies for specifically named surgical curricula were included with both full terms and acronyms. No search limits were applied and all languages were included.

Web search was done on American Society of Endocrine Surgery database (www.endocrinesurgery.org), the International Endocrine Surgeons Society (www.iaes- endocrine-surgeons.com) database and the Brazilian Endocrine Surgical Society records (SBEC, www.endocrinologiacirurgica.org.br), Australia and NZ endocrine surgeons (http://www.endocrinesurgeons.org.au), Belgian Endocrine Society (http://www.endocrinesociety.be), European Society of Endocrine Surgeons (http://www.eses.cc/), European Thyroid Association (http://www.eurothyroid.com/), French Endocrine Society (http://www.sfendocrino.org/), Japanese Society of Thyroid Surgeons (http://square.umin.ac.jp/thyroidsurgery/), Russian partnership for head and neck oncologists specialists (http://www.headneckonco.ru/), Endocrine Society of Thailand (http://www.thaiendocrine.org/), British Thyroid Association, Association of Surgeons of Great Britain and Ireland, British Association of Endocrine and Thyroid Surgeons (BAETS) (http://www.british-thyroid-association.org, http://www.asgbi.org.uk, http://www.baets.org.uk) and Indian Association of Endocrine Surgeons (http://iaes.org.in/). The final search was performed in December 2016.

All publications on thyroid, parathyroid and adrenals from India were searched by PubMed data network (http://www.ncbi.nlm.nih.gov/pubmed). Of these publications, those related to endocrine surgery were selected and listed in chronological order. ‘Thyroid, India’, ‘Thyroid surgery, India’, ‘Thyroidectomy India’, ‘Paratyhroid, India’, ‘Parathyroid surgery, India’, ‘Parathyroidectomy, India’, ‘Hyperparathyroidism, India’, ‘Adrenal, India’, ‘Adrenal surgery, India’ and ‘Adrenalectomy, India’. Only original articles were included; case reports, letter to the editor and commentaries were excluded. Manuscript distribution according to years was also determined. Articles were classified as thyroid, parathyroid and adrenal. The final search was performed in December 2016.

Data Extraction

We extracted the following data: a brief description of the programme, years of training required, the name of national oversight organisation(s), in-country opportunities for subspecialty training, endocrine surgery fellowship positions available, entry and exit criteria, funding, curriculum and the agency involved in the accreditation of such fellowship/courses.

Results

Worldwide Distribution of Endocrine Surgeons

Extensive search revealed that the number of endocrine surgeons has increased over the last decade worldwide. The exact number of practicing endocrine surgeons is extremely difficult to identify. Hence, we took a number of members of national associations as a surrogate for the number of endocrine surgeons in that country. But there is an inherent bias in this method. The online database is not updated regularly for most associations and usually includes potentially older surgeons; younger surgeons with endocrine surgery-specific training who are just starting practice usually delay their membership application. The total number of specialist endocrine surgeons is 1165 worldwide (Fig. 1). (https://www.iaes-endocrine-surgeons.com/iaes-members) In the last 6 years, the global number of endocrine surgeons has increased by 47%.

Fig. 1
figure 1

Scenario of ESx associations and ESx surgeons worldwide. There has been an increasing trend of endocrine surgery associations as well as endocrine surgeons worldwide

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Reliable information could be obtained for the USA. The total members of the American Association of Endocrine Surgeons (AAES) are 312 (https://www.endocrinesurgery.org/Membership/Find-a-Surgeon). The American Thyroid Association (ATA) members who are not a member of AAES are approximately 200 (https://members.thyroid.org/ATAMembers/Directory/ATAMembers/Directory?WebsiteKey=c617c2af-4682-4907-b140-bb0409b2ec46). (This was obtained after scrutinising the names of members for each association and removing duplicate names.) Apart from members of the ATA and AAES, new fellows after 2012 are approximately 114 [9]. The total number of endocrine surgeons in the USA added to 616. For India, we took the members of the Indian Association of Endocrine Surgeons as surrogate and the total members are 439 (http://iaes.org.in/images/Members%20List.pdf). Similarly, the total members for the Australia and NZ association of endocrine surgeons are 107 (http://www.endocrinesurgeons.org.au/Default.aspx?CCID=4261&FID=79727&ExcludeBoolFalse=True&ID=/member-results) and for the British Association of Thyroid and Endocrine surgeons are 232 (https://www.baets.org.uk/memberprofiles/?id=47&proc=&sergeon). These number of surgeons includes certified endocrine surgeons with a fellowship/degree/diploma as well as surgeons mainly practising endocrine surgery (Members of official endocrine surgeons association) (Fig. 2).

Fig. 2
figure 2

Number of endocrine surgeons per country. (Note: number of surgeons includes certified endocrine surgeons with a fellowship/degree/diploma as well as surgeons mainly practising endocrine surgery)

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Associations and Chapters

A search of the web was made in order to identify the associations of endocrine surgeons. The Indian Association of Endocrine Surgeons (IAES) was formed in September 1979 during the meeting of the International Society of Surgery in San Francisco. During the same time, in 1981 at a meeting in Birmingham, the British Endocrine Surgical Group was formed and in 2007, the members voted to change the name to ‘British Association of Endocrine and Thyroid Surgeons’ as we know it today. The American Association of Endocrine Surgeons is one of the oldest endocrine surgery associations. It was established in 1981 and has been continuously promoting the art of ES.

Asia was not lagging behind in terms of recognition and development of this subspecialty. The Asian Association of Endocrine Surgeons (Asian AES) was established in 1986. The Indian Association of Endocrine Surgeons (IAES) was formed as a section of the Association of Surgeons of India in the year 1993. Recent associations are formed in South Korea (Korean association of thyroid and endocrine surgeons), Turkey (Turkish association of endocrine surgery) and Brazil (Brazilian Endocrine Surgical Society). The number of countries with professional associations is increasing (Fig. 1); however, the pace is very slow. Only 11 countries are having a professional association of endocrine surgeons.

Fellowship/Training Opportunities

There is a great variation in the availability of fellowships for aspirant endocrine surgeons. The American Association of Endocrine Surgeons was instrumental in starting an accredited fellowship programme in 2000. Figure 3 shows the number of fellowships available in 2016.

Fig. 3
figure 3

Increasing number of endocrine surgery fellowship/degree/diploma positions by year in India and worldwide. In the past 6 years, the number of positions has increased by 100% worldwide and 350% in India

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Endocrine Surgery Training in India

India is the leader in the whole of Asia in terms of endocrine surgery training. Initial development of ESx in India was almost on par with developed countries with the establishment of the endocrine surgery department at Sanjay Gandhi Postgraduate Institute of Medical Sciences dating back to September 1989. Though initiation was contemporary, development at other institutes was very slow. SGPGIMS, in the year 1997, started the 1-year Postgraduate Diploma Certificate Course (PDCC) which was approved by the university. From 1997 to 2006, a total of 14 recipients got this diploma and dispersed all over India to start new academic centres. Two recipients are presently working at SGPGIMS itself. One recipient was instrumental in starting a new endocrine surgery department at King George Medical College Lucknow. Others are mostly working in private set up. Awardance of a super-specialty degree in India is different from the USA. In India, after obtaining the first postgraduate degree, that is MD/MS/FCPS/DNB, one can go for further specialisation in medical or surgical fields. This involves a highly competitive entrance examination. The course has 3 years of additional training and study and then after passing an examination, both theory and practice, the degree awarded is Doctor of Medicine ( DM) or Magister Chirurgiae (MCh). Centres offering MCh must be accredited by the Medical Council of India which is the central regulatory body for medical education in India.

In 2004, SGPGIMS started a 3-year MCh training programme approved by the Medical Council of India but the first candidate was admitted in 2005. In 2010, Madras Medical College, Chennai, also got an approval for MCh training programme. Subsequently, Christian Medical College, Vellore, started this programme in 2014 taking a total number of training centres to three. In 2016, All India Institute of Medical Sciences, New Delhi, also joined this bandwagon with the introduction of MCh training programme with three intakes per year (two candidates through entrance examination and one sponsored candidate, currently admission process is underway; https://www.mciindia.org/CMS/information-desk/college-and-course-search—last assessed on 1 Jan 2017 (Table 1)).

Table 1 Endocrine surgery training in India
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Organising Activity

A search on the web was made on relevant endocrine surgery association websites in order to identify there organising activities, meetings and CMEs. The International Association of Endocrine Surgeons holds bi-annual meetings. The American Association of Endocrine Surgeons is holding regular annual meetings for the past 37 years. The Asian Association of Endocrine Surgeons also organises bi-annual meetings. The Korean Association of Thyroid and Endocrine Surgeons (http://www.kates.or.kr/), Indian Association of Endocrine Surgeons (http://iaes.org.in/meetings.html) and Japanese Association of Endocrine Surgeons are Asian societies which hold regular annual meetings.

Research Activity

In the search performed, 440 original articles were identified to have been published on thyroid, parathyroid and adrenal from our country in the field of endocrine surgery between 1975 and 2016, 57% being made in the last decade. One hundred and ninety-two of the 440 manuscripts were written between 1975 and 2005, while the rest were published after 2005 (Fig. 1). When the distribution of the articles according to the specialty of the author was analyzed, it was identified that endocrine surgeons (only practising endocrine surgeons or with a degree or diploma in ESx) contributed most number (52%) of publications as compared to surgical oncologists, ENT surgeons and general surgeons. When we exclude thyroid from the list, then approximately 86% of publications are authored by endocrine surgeons.

We can see the impact of structured ESx training on research activity as most numbers of research articles in the last decade are from dedicated ESx centres. ESx with degree or diploma contributed to more than 80% of publications in the last decade which was around only 26% in the previous decade. In the last decade, department of ESx at SGPGIMS published 29% of total publications from India on thyroid, parathyroid and adrenal (Table 2).

Table 2 Research publications on endocrine diseases from India
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Discussion

The interest in advanced endocrine surgery training has increased due to increased incidence of endocrine diseases, better availability of training programmes and better job prospects [10, 11]. This is reflected in this research also. The number of trained endocrine surgeons has increased over the last decade. Data from this analysis shows that the USA is leading the pack with most number of endocrine surgeons. Among LMICs, India has the highest number of endocrine surgeons.

The association between volume and outcomes for complex surgical procedures has now been well established. This is true for surgical procedures for endocrine disorders as well and dedicated endocrine surgery department leads to improved clinical outcome [12,13,14,15,16]. Structured training programmes have helped in establishing new units. The precise number of endocrine surgery training programmes worldwide is difficult to determine. The aim was to identify the accredited training programmes worldwide, whether by a professional body or by the regulatory body of that country. An informal survey of academic departmental websites, official websites of professional bodies and regulatory bodies identified 68 accredited training programmes worldwide. Again, the USA has got the maximum number (n = 23) of academic centres offering structured training programme accredited by AAES. Canada has one training centre whereas the whole of Latin America has got only three training programmes for 600 million population. In the European Union, we could identify 11 training programmes accredited by the European Board of Surgery, Division of Endocrine Surgery. All of these programmes are accredited by professional bodies of the respective country and most of them are for 12- to 14-month duration. Among Asian countries, India is having the maximum number of accredited training programmes (n = 4). In India, the Medical Council of India is the central regulatory body which gives accreditation to all medical degree programmes. The three-year super-specialty programme in endocrine surgery is available at four centres in India which leads to a degree of MCh (Magister Chirurgiae). Countries with structured training programmes are the countries where more and more centres of training are coming up.

As the recognition of endocrine surgery is increasing, so is the number of professional bodies but it is still very less. Only 11 countries have a professional body of worldwide and this number is fairly constant since last decade. Most of these associations hold regular annual meetings. There are three regional associations, European Society of Endocrine Surgeons, Asian Association of Endocrine Surgeons and Australia and New Zealand Association of Endocrine Surgeons. Then, there is the International Association of Endocrine Surgeons. These associations hold bi-annual meetings. There is a significant association between countries with professional bodies, number of endocrine surgeons and number of accredited training programmes.

Another measurable impact of a structured training programme is on research activity. Demir et al. [17] from Turkey have reported an increasing number of publications since 2002, which in turn results in an increasing significance of Turkey in the international arena in endocrine surgery due to the current acceleration. Similarly, Duenas et al. [18] searched on PubMed looking for the articles published by the 21 identified Latin American endocrine surgeons. A total of 62 publications were identified; 70% were from Mexican authors followed by publications from Brazil, Colombia and Guatemala. They concluded that many research projects are currently underway and hopefully, the number of research articles from Latin American endocrine surgeons will increase in the near future. Similar encouraging results were seen in our research. We can see the impact of structured training on research activity in India, as most numbers of research articles in the last decade are from dedicated endocrine surgery centres. An endocrine surgeon with a degree or diploma contributed to more than 80% of publications in the last decade which was around only 26% in the previous decade. In the last decade, the Department of Endocrine Surgery at SGPGIMS published 29% of total publications from India on thyroid, parathyroid and adrenal.

Conclusion

The establishment of professional endocrine surgery bodies by motivated endocrine surgeons and initial institution-based fellowships is a powerful factor that has influenced the present growth of endocrine surgeons and endocrine surgery training programmes. Significant variation is found in the case of distribution of fellowships and fellows worldwide with a relative paucity in developing countries. Over three-quarters of the countries of the world have not developed training programmes in endocrine surgery. The findings of this study will influence the promotion of new professional bodies, training programmes and workforce distribution.

Limitations

Our study has several limitations. Findings exclude many graduates from endocrine surgery fellowships who may not be members of endocrine surgeons association of their countries. Clinical practice can be highly variable despite being a member of an endocrine surgeons association and online database would identify potentially older surgeons with extensive experience and may exclude younger surgeons with endocrine surgery-specific training who are just starting practice. Furthermore, our study has limitations inherent to online surveys, i.e. websites may not be updated regularly. In addition, we were limited by a small response rate from few leaderships of endocrine surgeons association when we tried to verify data obtained from web search by personal communication. The results of this study may not reflect accurately the current fellowship positions and a number of endocrine surgeons but it gives an approximate idea of the present day landscape of endocrine surgery training programme and the impact of a structured residency programme in India in development of this subspecialty.