Prostate cancer research in India: A scientometric analysis of publications output during 2004-13

This review article examines 1,368 publications on prostate cancer in India, as covered in Scopus database during 2004-13, experiencing an annual average growth rate of 18.77% and citation impact of 5.23. The world prostate cancer output (89,994 publications) came from several countries, of which the top 15 (United States, United Kingdom, Germany, Canada, Italy, Japan, and China) accounts for 94.80% share of the global output during 2004-13. India’s global publication share was 1.52% and hold 14th rank in global publication output during 2004-13. The Indian prostate cancer output came from several organizations and authors, of which the top 20 and 19 contributed 41.81% and 24.05% share, respectively, during 2004-13. India’s international collaborative share in prostate cancer was 23.39%, which decreased from 24.42% to 22.98% from 2004-08 to 2009-13. Medicine accounted for the largest share (59.50%) of output in prostate cancer followed by biochemistry, genetics and molecular biology (40.13%), pharmacology, toxicology & pharmaceutics (27.63%), chemistry (8.55%), agricultural and biological sciences (4.31% share), and immunology and microbiology (2.70% share) during 2004-13. Diagnosis, screening, chemotherapy, radiotherapy, pathology and prognosis together account for 60.24% publications share among treatments methods used in Indian prostate cancer research during 2004-13. Only Delhi, Maharashtra, Uttar Pradesh and Tamil Nadu together contributed 57.82% share in Indian publications output in prostate cancer during 2004-13. The authors stressed the need for developing national policy for prostate cancer which should take care of screening for detection and diagnosis, management and treatment options of the prostate cancer patients in India.


Introduction
The prostate gland is part of a man's reproductive and urinary systems. It is oval shaped with a rounded tip and its size varies (with age) from the size of a walnut to a small apple. The prostate surrounds the base (or neck) of the bladder. It has 2 lobes that surround the urethra. The urethra carries urine from the bladder, through the prostate, and out the penis. The prostate gland is covered in a layer of connective tissue called the prostatic capsule and is made up of different types of cells: (i) gland cells that produce the fluid portion of semen, (ii) muscle cells that control urine flow and ejaculation and (iii) fibrous cells that provide the supportive structure of the gland. Around the prostate, there are structures: (i) seminal vesicles -these glands produce semen and are found on both sides of the prostate, (ii) vas deferens -these tubes carry sperm from the testicles to the seminal vesicles, (iii) nerve bundles -these nerves control bladder and erectile function and are found on both sides of the prostate and (iv) muscles -these muscles control urination. 1 The prostate gland is divided into three zones: (i) peripheral zone-it is the largest part of prostate and closest to the rectum. This zone accounts for approximately 75% the prostate tumors (approximately 75%); (ii) transition zone -a middle area of the prostate (about 20% of the prostate gland) and surrounds the urethra as it passes through the prostate; and (iii) central zone-The area in front of the transition zone of the prostate and is farthest from the rectum. The main function of the prostate is to produce the fluid portion of semen. A thin fluid (made continuously) rich in proteins and minerals that maintain and nourish sperm is produced by the gland cells within the prostate. When a man is sexually aroused, the prostate produces larger amounts of this fluid. It then mixes with sperm and is ejaculated as semen. However, its excess production passes from the body to the urine. The prostate also plays a part in controlling the flow of urine. The urethra runs from the bladder, through the prostate, and out through the penis. The muscle fibers of the prostate are wrapped around the urethra and are under involuntary nervous system control. These fibers contract to slow and stop the flow of urine. 1 Prostate cancer starts in the cells of the prostate several types of cells are found in the prostate, but almost all prostate cancers develop from the gland cells. Gland cells make the prostate fluid that is added to the semen. The cancer that starts in gland cells is called isadenocarcinoma. Other rare types of cancer can also start in the prostate gland, including sarcomas, small cell carcinomas, and transitional cell carcinomas. 2 Prostate cancer is the second most common cancer (with 15% of all cancer cases) in men, with an estimated 1.1 million cases (developed region -759,000 cases, developing regions -353,000, India-19,000) is diagnosed in 2012. The prostate cancer incidence varies across different geographical regions. It is very high in developed regions such as Australia/New Zealand and North America (Age Standardized Rates (ASR) 111.6 and 97.2 per 100,000 respectively). It is high in terms of Age Standarized Rates in few developed regions such as Caribbean (79.8), South Africa (61.8) and South America (60.1) and low in Asian region with estimated rates of 10.5 and 4.5 in Eastern and South Central Asia. With an estimated 307,000 deaths (developed regions-142,000, developing regions-165,000 and India-12,000) in 2012, prostate cancer is the fifth leading cause of death from cancer in men (6.6% of the total men deaths). Mortality rates in terms of Age Standarized Rates are observed generally high in predominantly black population (Caribbean, 20 per 100,000), Sub-Saharan Africa (ASRs 19-24 per 100,000), very low in Asia (2.9 per 100,000 in South Central Asia) and intermediate in the Americas and Oceania. 3 In the past, there are no specific studies on the scientometric analysis of prostate cancer research both at global and national level. However, only few studies have been undertaken in the past on the contribution, citation impact, and evaluation of Indian cancer literature. Among such quantitative studies, Patra and Bhattacharya 4 had analyzed World and Indian oncology research output during 1987-2003, using PubMed database. It studied research output and global contribution of different countries in world output. It mainly studied India's cancer literature growth trends and explored the application of Bradford's Law of Scattering for identifying core journals and Lotka's Law for author productivity in Indian literature. It also identified the most active Indian institutions involved in cancer research. Lewison  Publication productivity and citation impact of most productive twenty Indian institutions and nineteen authors; and  Leading media of communication

Literature search
The study retrieved and downloaded the publication data of the world and of 15 most productive countries in prostate cancer from the Scopus database (http://www.scopus.com) for 10 years during 2004-13. The keyword "prostate cancer" and "cancer or neoplasm or carcinoma" were used in "title, abstract and keyword" tag and restricting it to the period 2004-13 in "date range tag" was used for searching the global publication data and this become the main search string. When the main search string with restricted to 15 most productive countries in "country tag", as shown below, the publication data on productive countries were obtained. When the main search string is further restricted to "subject area tag", "country tag", "source title tag", "journal title name" and "affiliation tag", we got information on distribution of publications by subject, collaborating countries, organiza-
The largest number of inter-country collaborative linkages (1457)

Profile of top 20 most productive organizations
The productivity of 20 most productive Indian organizations in prostate cancer varied from 11 to 90 publications and together contributed 41.81% (572 publications) share in the cumulative publications output of India in prostate cancer research during 2004-13. The scientometric profile of these 20 Indian organizations is presented in Table 9.

Profile of top 19 most productive Indian authors
The top 19 most productive Indian authors have published 11 to 44 publications each and together contributed 24.05% (329 publications) share in the cumulative publications output of India in prostate cancer research during 2004-13. The scientometric profile of these 19 Indian authors is presented in Table 10.

Conclusion
In order to increase the national output and international collaboration and improve citation impact, there is an urgent need to increase awareness and understanding of the burden of disease associated with prostate cancer, undertake the evaluation of existed prostate cancer related programs and establish a national prostate cancer program at the national level in India. It is also important to develop a systematic screening program for detection and diagnosis of prostate cancer cases to be followed by evolution of suitable management strategy and more effective treatment options for treatment of prostate cancer. There is also need to increase funding support for research and development (R&D) and develop training programs for concerned persons at different levels.