Analysis of transurethral resection of prostate videos on YouTube™: Educational quality assessment

Summary

Background: Our aim was to evaluate the educational value of transurethral resection of prostate (TURP) videos on YouTube.

Methods: A comprehensive search was conducted for TURP videos on YouTube. Based on the Laparoscopic Surgery Video Educational Guidelines we created a checklist which includes 20 items for evaluation of the videos. IBM SPSS statistics was used for analysis

Results: A total of 104 surgical videos were assessed. The mean view count was 15647 3 (21-324 522, SD 47556 4) Video image quality found as low for 57 7% of videos Both staff (76%) and resident (75%) rated most of the videos low educational quality No statistically significant difference was found between staff’s total points (mean 4 35 ± SD 2 9) and resident’s total points (mean 4 63 ± SD 3 3) (p: 0 761) Positive correlation was found between view count and staff’s total points (r: 0 242 p < 0 05), resident’s total points (r: 0 340 p < 0 01) There was also positive correlation between number of likes and staff’s total points (r: 0 375 p < 0 01) and resident’s total points (r: 0.466 p < 0.01).

Conclusions: Most TURP surgical videos on YouTube are low quality. Higher educational quality videos with detailed explanation of the procedure are needed on this subject We believe this study could be a guide for future high quality TURP videos.

KEY WORDS: Transurethral resection of prostate; Benign prostatic hyperplasia; Social media; Video recording; Data quality

Submitted 11 April 2023; Accepted 27 April 2023

Introduction

Benign prostatic hyperplasia (BPH) is a histologic diagnosis which is characterized by proliferation of smooth muscle and epithelial cells of the periurethral prostatic tissue Its prevalance increases with age reaching 90% by the ninth decade of life at autopsy studies (1) BPH is the leading cause of male lower urinary tract symptoms (LUTS) (2) Most men after 45 suffer at least one component of LUTS and symptoms are mostly mild (3) With aging global population and high prevelance of LUTS especially in elderly men, treatment of male LUTS will become even more important in the future

Treatment options for BPH related male LUTS are cons e r v a t i v e t r e a t m e n t , p h a r m a c o t h e r a p y a n d s u r g e r y

Surgical management of BPH can basically divided into three main groups; open prostatectomy, minimally inva- sive techniques (laparoscopic, robotic prostatectomy) and endoscopic interventions First resectoscope and the first transurethral resection of prostate (TURP) procedure was introduced by Maximilian Stern in 1926 (4) With technological advances, TURP became more and more popular and has been considered the reference technique for the surgical management of BPH Despite the decline in the rate of TURP for BPH surgery due to development of various alternative techniques such as Holmium laser enucleation of prostate (HoLEP), TURP is still the most frequently taught and performed surgical technique for BPH (5)

The internet's baby steps began to be taken in the 1960’s and accelerated in the 80’s (6) Nowadays, 60% of the world’s population has access to internet (7) With portable electronic devices online resources have become an important part of education in general Videos are easily accessible, allow creating personal time and space for learning By watching videos online, one can learn different techniques from various surgeons, interact with colleagues around the world, exchange ideas and improve skills With fewer opportunities being found lately by trainees in the operating rooms due to work hour restrictions, high costs, patient safety measures (8), videos became a crucial learning method in surgical training Many surgical videos are avaliable online and advantages of these videos in surgical education have been shown in various studies (9, 10)

YouTube™ (Google, LLC) which was founded on 2005, is the second most popular website in the world with over 33 billion total visits in June 2022 (11) and the biggest source of videos on the internet Studies showed that YouTube™ is the most widely used platform by both residents and surgeons for surgical education (12, 13) There is a great opportunity to learn about surgical techniques and improving skills with watching videos on YouTube™ However, since there is lack of professional p e e r r e v i e w a n d q u a l i t y c h e c k o f t h e v i d e o s o n YouTube™ , surgical videos may be untrustworthy In this study we aimed to evaluate the educational quality of TURP videos on YouTube™

Materials And Methods

In this study we evaluated TURP surgery videos which are avaliable for the public Therefore, no ethical approval is required A comprehensive search was performed in October 31, 2022 on YouTube™(https://www.youtube.com) using the search terms “tur prostate” , “tur prostatectomy” , “tur p ” , “monopolar tur p ” , “bipolar tur p ” seperately The videos were selected by the first author based on following criterias: traditional resection of the prostate must be performed either with monopolar or bipolar systems, live surgery recorded by endoscopic camera systems, videos made by professionals and videos in English language Videos including multiple surgeries, externally recorded videos, commercial videos, slide based presentation videos and animation videos and non- English videos were excluded from the study 104 videos met these criterias and were included the study (Figure 1) Characteristics of the videos were view count, number of likes, days online, video length, region, video image quality (480p resolution: low, 720p resolution: medium, 1080p resolution: high)

There are several reports assessing YouTube™ videos from patient’s perspective, rating their understandibility and patient educational value (14, 15) In this report, we tried to evaluate TURP videos on YouTube™ as tools for surgical education No guideline for assessing the educational value of TURP videos were present First author which is a junior staff urologist and the third author which is a senior staff urologist created a video quality checklist based on the checklist that was developed for the evaluation of laparoscopic surgery videos (16) The checklist included five major categories which were author’s information, case presentation, critical steps of the procedure, outcomes of the procedure, supplementary contents with a total of 20 items Each item represented one point (Table 1) First author and second author which was a junior res-

The checklist for the evaluation of TURP surgical videos' educational quality

Items of checklist

Author’s Information

1 Author’s information

2 Title of the video including the procedure

3 Conflict of interest disclosure

Case Presentation

4 Patient privacy protection

5 Patient characteristics

6 Preoperative work-up

7 Prostate volume

Critical steps of the procedure

8 Introduction of the equipments

9 Setting of cut and coagulation

10 Anatomic demonstration

11 Step by step explanation

12. Explanation of the critical steps

Outcomes of the procedure

13 Operating time

14 Volume of resected specimen

15. Length of hospitalization

16 Intraoperative and postoperative complications

17 Functional outcomes

Supplementary contents

18 Educational tables and photos

19 Audio commentary

20 Video commentary ident evaluated the videos and scored each video from 1 to 20 Videos were divided into 4 educational quality groups according to their total score; low quality (0-5 points), medium quality (6-10 points), high quality (1116 points) and very high quality (16-20 points) With scoring videos separately by a staff surgeon and a resident we aimed to not only evaluate the educational quality of the videos but to determine if there is a difference between a resident’s and a surgeon ’ s evaluation

Statistical analysis

Statistical analysis was performed with IBM SPSS software (version 26 for MacOS, IBM Corporation, NY, USA) The characteristics of the videos were presented as mean, median, ranges, standard deviation (SD) The distribution of the variables was measured by Kolmogorov- Smirnov test Mann Whitney U test was used for the comparison of two reviewers mean points Pearson’s correlation coefficient was used to evaluate the correlations between variables P < 0 05 was considered statistically significant

Results

Total of 104 videos were evaluated The mean view count was 15647 3 (range 21-324 522, SD 47556 4) Mean like count was 30 8 (range 0-285, SD 54 7) The median days avaliable online was 1856 5 (137-5943) (Table 2) Videos w e r e s o u r c e d f r o m A s i a ( 6 5 3 % ) , E u r o p e ( 1 5 3 % ) , Unknown region (14 4%), USA (2 8%) and Australia (1 9%) 73 (70 1%) videos were uploaded by private users, 15 (14 4%) videos by medical organizations and 16 (15 3%) videos by unknown users Video image quality was found as low for 60 (57 7%), medium for 25 (24%) and high for 19 (18 3%) videos No statistically significant difference was found between staff’s total points (mean 4 35 ± SD 2 9) and resident’s total points (mean 4 63 ± SD 3 3) for the evaluation of the videos (p: 0,761) (Table 3) No video received full points from the checklist Both staff urologist (79/104, 76%) and resident (78/104, 75%) rated most of the videos low educational quality Resident rated 8 (7 7%) videos high quality while staff urologist rated 5 (4 8%) Only one video rated very high quality and it was by the staff urologist

The correlation test showed positive correlation between view count and number of likes (r: 0 787 p < 0 01), staff’s total points (r: 0 242 p < 0 05), resident’s total points (r:0 340 p < 0 01) and days online (r: 0 477 p < 0 01) There was also positive correlation between number of likes and staff’s total points (r: 0 375 p < 0 01) and resident’s total points (r: 0 466 p < 0 01)

There was a positive correlation between staff’s total points and resident’s total points (r: 0 887 p < 0 01) Negative correalation was found between days online and video lenght (r: 0 207 p < 0 05) and staff’ total points (r: 0 195 p < 0 05) (Table 4)

Discussion

In this study our purpose was to evaluate TURP videos on YouTube™ to estimate their educational value, define the pros and cons of the videos and try to set a standard for future high quality videos To our knowledge, this is the first report to review the quality of TURP videos on YouTube™

In this report we demostrated that most of the TURP videos on YouTube™ have low educational quality In the majority of videos; there was limited information regarding patient’s data Most videos consisted of edited or unedited footage of the surgery and did not include any explanation of the critical steps regarding the procedure Very few of the videos have mentioned outcomes of the procedure Additionally image quality were low in most videos These major defects resulted in videos that were not suitable for educational purpose

There are several studies in the literature assessing surgery videos on YouTube™ A study on videos about surgical treatment of LUTS/BPH indicated low quality content in the vast majority of the videos (17) Yang et al evaluated 70 ThuLEP videos on YouTube™ and concluded that there is lack of high educational valued videos on this topic (18) A review of 32 mid urethral sling videos on YouTube™ showed that none of the videos demonstrated the complete list of critical steps of the procedure (19) Loeb et al reported that overall information quality was moderate to poor in 67% of 150 bladder cancer videos on YouTube™ and moderate to high misinformation was present in 21% of the videos (20) Haslam et al assessed 23 robotic pyeloplasty videos on YouTube™ and found out that only 6 videos included all critical steps of the procedure (21) These studies along with our ’ s outlined that, although

YouTube™ has a wide variety of medical videos, there are great heterogeneity in their quality Great care must be taken when using YouTube™ videos as a source of information, because most of the videos contain inaccurate and incomplete information about the procedures, which may prove to be harmful than educational, especially for inexperienced learners Videos from academic institutions tend to be more high quality than videos from single users (22) Sources with rigorous review processes like official websites of urological associations (i e American Urological Association, European Association of Urology) or video sections of certain urology journals may be used for more credible information

Our study has limitations Firstly, we evaluated videos on YouTube™ solely hence more websites should be included for more comprehensive view of the quality of TURP videos But since YouTube™ is the most popular source for surgical videos we believe these results have great value Secondly, the fact that one of the reviewer was a junior resident with little experience on TURP could have introduced bias into the study However no statistically significant difference was found between two reviewers evaluations thus this suggests that his inexperience did not have any effects on our findings and our findings are reliable Lastly we were obligated to create a checklist for evaluation of TURP videos because no other study has addressed this subject before More studies are needed to develop a standardizied and validated checklist

Conclusions

YouTube™ lacks high educational quality videos of transurethral resection of the prostate It is important to detect high quality videos and verify the information with multiple sources We believe that this study can guide future high educational quality videos

References

1 Berry SJ, Coffey DS, Walsh PC, Ewing LL The development of human benign prostatic hyperplasia with age J Urol 1984; 132:474-9

2 Parsons JK Benign Prostatic Hyperplasia and Male Lower Urinary Tract Symptoms: Epidemiology and Risk Factors Curr Bladder Dysfunct Rep 2010; 5:212-218

3 McVary KT BPH: epidemiology and comorbidities Am J Manag Care 2006; 12(5 Suppl):S122-8

4 https://www baus org uk/ user files/pages/files/Museum/20%20%20TURP pdf

5 Malaeb BS, Yu X, McBean AM, Elliott SP National trends in surgical therapy for benign prostatic hyperplasia in the United States (2000-2008) Urology 2012; 79:1111-6

6 https://www britannica com/story/who-invented-the-internet

7 https://data worldbank org

8 Pugh CM, Watson A, Bell RH Jr, et al Surgical education in the internet era J Surg Res 2009; 156:177-82

9 Friedl R, Höppler H, Ecard K, et al Development and prospective evaluation of a multimedia teaching course on aortic valve replacement Thorac Cardiovasc Surg 2006; 54:1-9

10 Pape-Koehler C, Immenroth M, Sauerland S, et al Multimedia- based training on Internet platforms improves surgical performance: a randomized controlled trial Surg Endosc 2013; 27:1737-47

11 https://www similarweb com/top-websites/

12 Rapp AK, Healy MG, Charlton ME, et al YouTube is the Most Frequently Used Educational Video Source for Surgical Preparation J Surg Educ 2016; 73:1072-1076

13 Mota P, Carvalho N, Carvalho-Dias E, et al Video-Based Surgical Learning: Improving Trainee Education and Preparation for Surgery J Surg Educ 2018; 75:828-835

14 Shoemaker SJ, Wolf MS, Brach C Development of the Patient Education Materials Assessment Tool (PEMAT): a new measure of understandability and actionability for print and audiovisual patient information Patient Educ Couns 2014; 96:395-403

15 Morra S, Napolitano L, Collà Ruvolo C, et al Could YouTube™ encourage men on prostate checks? A contemporary analysis Arch Ital Urol Androl 2022; 94:285-290

16 Celentano V, Smart N, McGrath J, et al LAP-VEGaS Practice Guidelines for Reporting of Educational Videos in Laparoscopic Surgery: A Joint Trainers and Trainees Consensus Statement Ann Surg 2018; 268:920-926

17 Betschart P, Pratsinis M, Müllhaupt G, et al Information on surgical treatment of benign prostatic hyperplasia on YouTube is highly biased and misleading BJU Int 2020; 125:595-601

18 Yang K, Meng Y, Zhang K Educational value of YouTube Surgical Videos of Thulium Laser Enucleation of The Prostate (ThuLEP): the quality assessment Transl Androl Urol 2021; 10:2848-2856

19 Larouche M, Geoffrion R, Lazare D, et al Mid-urethral slings on YouTube: quality information on the internet? Int Urogynecol J 2016; 27:903-8

20 Loeb S, Reines K, Abu-Salha Y, et al Quality of Bladder Cancer Information on YouTube Eur Urol 2021; 79:56-59

21 Haslam RE, Seideman CA Educational Value of YouTube Surgical Videos of Pediatric Robot-Assisted Laparoscopic Pyeloplasty: A Qualitative Assessment J Endourol 2020; 34:1129-1133

22 Sahin Y, Paslanmaz F, Ulus I, et al Quality and content analysis o f f e m a l e u re t h ro p l a s t y v i d e o s o n Yo u Tu b e L o w U r i n Tr a c t Symptoms 2023; 15:24-30

Correspondence

Yavuz Karaca, MD mdyavuzkaraca@gmail com

Emre Burak Sahinler, MD emre sahinler@yahoo com

Orhun Sinanoglu, MD orhundr@hotmail com

Department of Urology, Sancaktepe Sehit Prof Dr Ilhan Varank Research and Training Hospital, Istanbul, Turkey

Didar Ilke Karaca, MD karacailke@yahoo com

Department of Public Health, Marmara University School of Medicine, Istanbul, Turkey

Conflict of interest: The authors declare no potential conflict of interest

with non-muscle invasive bladder cancer

Summary

Objective: To evaluate the utility of infantile BCG vaccination history in predicting stage and grade of tumours in non-muscle invasive bladder cancer (NMIBC)

Materials and methods: We retrospectively analyzed data from patients from a single center who were diagnosed with new NMIBC and underwent transurethral resection of bladder tumour (TURBT) between 2017 and 2022 We assessed BCG immunization status with various demographics and comorbidities, as well as tumour recurrence, progression, stage, and grade

Results: A total of 188 patients met the inclusion criteria for our study The mean age of patients at the time of diagnosis was significantly lower in those that had been immunized with BCG (71 ± 9) than those who had not (77 ± 10) (p < 0 0001) History of BCG immunization did not correlate with sex, history of diabetes mellitus (DM), prior history of intravesical BCG treatment, and tumour recurrence, progression, stage, and grade.

Conclusions: History of infantile BCG vaccination did not correlate with the depth of invasion and/or the grade in patients with non-muscle invasive bladder cancer Patients that received infantile BCG vaccination were significantly younger at the time of diagnosis of NMIBC

KEY WORDS: BCG; Non-muscle invasive bladder cancer (NMIBT); Bladder cancer

Submitted 11 April 2023; Accepted 26 May 2023

Introduction

Bladder cancer is the tenth most common malignancy worldwide, with increasing incidence, particularly in developed nations (1) Approximately 80% of bladder cancers arise in individuals aged 65 or older with the mean age being 73 years old (2, 3) This is thought to reflect a disease process requiring many decades of development following exposure to risk factors, such as tobacco (2) Urothelial carcinoma (UC) accounts for 90% of bladder cancers (4) At the time of presentation, approximately 70% of UC cases are non-muscle invasive (NMIBC), while 30% are muscle invasive (MIBC) (4) Initial management of NMIBC is transurethral resection of bladder tumor (TURBT) (4) For those with NMIBC who are deemed to be at high risk for progression, intravesical Bacillus Calmette-Guérin (BCG) is the gold standard adjuvant therapy (4)

The use of intravesical instillation of BCG for high risk NMIBC demonstrates a role for immunotherapy in UC BCG, originally used as a vaccine against tuberculosis (TB), contains live-attenuated Mycobacterium bovis (4)

The specific mechanism of BCG in NMIBC treatment continues to be studied, however, its role is attributed to both local immunological efforts and systemic immune responses (5) Some work has suggested that BCG vaccination may be associated with a lower rate of bladder cancer incidence (6) Despite this relationship, research on BCG immunization as a possible predictive factor in NMIBC has been limited In the present study, we evaluated the relationship between history of infantile BCG vaccination with the depth of invasion and the grade in patients with NMIBC

Methods

Data were retrospectively collected between 2017 and 2022 Inclusion criteria included all patients with a new diagnosis of NMIBC at the Thunder Bay Regional Health Sciences Centre (TBRHSC), for whom complete clinical, lab, and pathological data could be retrieved Data collected included the history of infantile BCG as well as the patients’ age, sex, comorbid status, CBC, vaccination, history of intravesical BCG instillation, pathological data, recurrence, and progression Vaccination status was correlated with these variables Institutional ethical approval was obtained from the TBRHSC research ethics board (RP741) Correlations between continuous variables were done using Student’s t-test Categorical variables were compared using Fisher Exact test A p-value of < 0 05 was used to define significance

Results

A total of 188 patients met the inclusion criteria for our study No patients were lost to follow up The mean follow-up time was 26 ± 7 months Of the 188 individuals meeting the eligibility criteria, 113 individuals had received the infantile BCG immunization and 75 did not

A s t a t i s t i c a l l y s i g n i f i c a n t d i ff e re n c e w a s i d e n t i f i e d between the age of individuals who had received the immunization and those who did not (p < 0 0001) The mean age at the time of diagnosis for those immunized was 71 ± 9 years, and 77 ± 10 in the non-immunized group There was no statistically significant difference found between immunization status and other patient characteristics including sex, history of diabetes mellitus (DM), or history of intravesical BCG treatment History of immunization did not correspond with tumour recurrence, progression, stage, or grade in this population

The results are summarized in Table 1 strated that BCG immunotherapy in NMIBC patients induced TI and provided protection against respiratory infections (9) This suggests that intravesical BCG therapy can produce similar systemic immune responses as the BCG vaccination Given that our data demonstrated that immunization status did not impact the tumour progression characteristics and risk stratification, this may suggest increased importance in the role of the local immune response in intravesical BCG in preventing the progression of NMIBC

Our findings may also be explained by the waning protection from immunization over time While bladder cancer incidence increases in the elderly (10), individuals immunized with BCG are typically immunized as infants It has been well documented that protection from this immunization against TB infections wanes over time (7) Studies have identified that a positive purified protein derivative (PPD) skin test, an indication of BCG immunity, was associated with a better response to intravesical BCG therapy than those with a negative reaction (11, 12) Niwa et al (2017) demonstrated that the recurrence-free survival (RFS) in patients with a slightly positive or negative PPD skin test reaction was significantly diminished compared to the RFS in those with a strongly positive response This may suggest that a reduced immune response from BCG immunization does not generate the same benefit in BCG treatment Given that the mean age of those vaccinated with BCG in our study was 71 years, and our study specifically looked at infantile BCG immunization, this may also explain why individuals with waning immunity from remote immunization did not influence tumour characteristics or risk stratification in patients with NMIBC

Discussion

Studies assessing the relationship between NMIBC and BCG immunization have been limited One scoping literature review identified a 35-37% lower age-standardized rate of bladder cancer incidence in individuals with BCG immunizations, suggesting an association between the two (6)

We demonstrated that BCG immunization did not correlate with tumour characteristics in NMIBC, including stage, grade, and risk stratification This may be explained by the routes of administration and subsequent immune responses elicited The anti-tumour activity of intravesical BCG therapy is attributed to non-specific immune mechanisms related to the direct interaction with urothelial cells, as well as a contribution of systemic immune response, though specific mechanisms have yet to be fully elucidated (7) BCG immunization is also associated with non-specific immune mechanisms that provide protection against tuberculosis, however, given the nature of vaccinations, this response is exclusively systemic (8) Interestingly, this generalized immune response from immunization has been shown to confer protection against other respiratory infections through a mechanism referred to as trained immunity (TI) (8, 9) It was demon-

In our study, the mean age of patients diagnosed with new N M I B C w a s s i g n i f i c a n t l y l o w e r i n i n d i v i d u a l s w h o received the infantile BCG vaccination (71 ± 9) compared to those who did not (77 ± 10) (p < 0 0001) Increased age is a risk factor for developing UC, largely attributed to a disease course that develops decades after exposure to risk factors (2) Countries with the lowest incidence of bladder cancer are typically those found to be below average on the human development index (HDI), which may be attributable to less industrial chemical exposure and access to tobacco, major risk factors for UC (1)

Interestingly, such countries tend to have a higher incidence of tuberculosis and subsequently higher rates of infantile BCG immunization (13) This may imply that non-immunized individuals were likely raised in countries with low TB incidence, yet above-average HDI Such individuals would likely have had a higher risk of exposure to industrial chemicals and tobacco, leading to the slow development of bladder cancer and presentation at a later age Those immunized and likely raised in countries with less exposure to common risk factors may have developed UC earlier on due to other reasons, such as genetics, diets, or other lifestyle factors

Older age at presentation has been shown to be a poor prognostic factor in NMIBC (4) Consequently, the older age of presentation with NMIBC in non-immunized individuals poses a significant healthcare concer n The incidence of bladder cancer has been steadily increasing, particularly in developed countries (1) Such countries do not tend to implement routine immunization against TB given the low incidence Consequently, there is a growing population of non-immunized individuals presenting with NMIBC and potentially at older ages This may result in overall more complicated patients with poorer prognostics Further research in this area would be of utility given the growing aging population and potentially increased demands on healthcare systems

There are several limitations to our study First, it is a retrospective study completed at a single center Therefore, selection bias was inevitable, and our study represents a relatively small sample size of patients This study also limited by the relatively short follow up period (26 + 7 months) for assessing recurrence and progression Additionally, we did not account for the various demographic factors that may influence the risk factors for developing NMIBC

Conclusions

Infantile BCG immunization was not associated with higher risk stratification in patients with NMIBT The mean age of patients diagnosed with NMIBC was significantly lower in patients who received the infantile BCG vaccination

References

1 Bray F, Ferlay J, Soerjomataram I, et al Global cancer statistics 2018: Globocan estimates of incidence and mortality worldwide for 36 cancers in 185 countries CA Cancer J Clin 2018; 68:394

2 Mushtaq J, Thurairaja R, Nair, R Bladder cancer Surgery (Oxf) 2019; 37:529

3 Siegel RL, Miller KD, Jemal A Cancer statistics, 2019 CA Cancer J Clin 2019; 69:7

4 Saginala K, Barsouk A, Aluru JS, et al Epidemiology of Bladder Cancer Med Sci 2020; 8:15

5 Taniguchi K, Koga S, Nishikido M, et al Systemic immune response after intravesical instillation of Bacille Calmette-Guérin (BCG) for superficial bladder cancer Clin Exp Immunol 1999; 115:131

6 Trigo S, Gonzalez K, Di Matteo L, et al Bacillus Calmette-Guerin vaccine and bladder cancer incidence: Scoping literature review and preliminary analysis Arch Ital Urol 2021; 93:1

7 Mukherjee N, Julián E, Torrelles JB, Svatek RS Effects of Mycobacterium bovis Calmette et Guérin (BCG) in oncotherapy: Bladder cancer and beyond Vaccine 2021; 39:7332

8 Covián C, Fernández-Fierro A, Retamal-Díaz A, et al BCGInduced Cross-Protection and Development of Trained Immunity: Implication for Vaccine Design Front Immunol 2019; 10:2806

9 van Puffelen J H, Novakovic B, van Emst L, et al Intravesical BCG in patients with non-muscle invasive bladder cancer induces trained immunity and decreases respiratory infections J Immunother Cancer 2023; 11:e005518

10 Martinez L, Cords O, Liu Q, et al Infant BCG vaccination and risk of pulmonary and extrapulmonary tuberculosis throughout the life course: a systematic review and individual participant data metaanalysis Lancet Glob Health 2022: 10:e1307

11 Niwa N, Kikuchi E, Matsumoto K, et al Purified protein derivative skin test reactions are associated with clinical outcomes of patients with nonmuscle invasive bladder cancer treated with induction bacillus Calmette-Guérin therapy Urol Oncol 2018; 36e15

12 Biot C, Rentsch CA, Gsponer JR, et al Preexisting BCG-specific T cells improve intravesical immunotherapy for bladder cancer Sci Transl Med 2012; 4:72

13 Centers for Disease Control and Prevention BCG Vaccine Fact Sheet 2016 Retrieved from https://www cdc gov/tb/publications/ factsheets/prevention/bcg htm

Correspondence

Anastasia MacDonald, MD anamacdonald@nosm ca

Vahid Mehrnoush, MD vahidmehrnoush7@gmail com

Asmaa Ismail, MD asmaaismail0782@gmail com

Ahmed Zakaria, MD aszakaria81@yahoo com

Waleed Shabana, MD waleed shabana@gmail com

Ashraf Shaban, MD ashraf shaban@tbh net

Mohammed Bassuony, MD mohammed bassuony@tbh net

Hazem Elmansy, MD hazem elmansy@tbh net

Walid Shahrour, MD walid shahrour@tbh net

Owen Prowse, MD owen prowse@tbh net

Ahmed Kotb, MD, PhD, FRCSC, FRCS Urol, FEBU (Corresponding Author)

Associate Professor drahmedfali@gmail com

Northern Ontario School of Medicine (NOSM) and Thunder Bay Regional Health Research Institute (TBRHRI)

Thunder Bay, ON, Canada

Livio Di Matteo, MD ldimatte@lakeheadu ca

Department of Economics, Lakehead University, Thunder Bay, ON

Conflict of interest: The authors declare no potential conflict of interest