br Data management was performed
Data management was performed using Microsoft Excel version 2016 (Seattle, Washington). Statistical analysis was performed using STATA version 14.0 (StataCorp LP, Col-lege Station, TX). Pearson chi-square and Fisher’s exact test were used to comparing proportions of categorical variables. Wilcoxon rank sum test was used to compare the distribution of continuous variables. Univariate and multivariate logistic regression models were performed to identify predictors for utilization of FT in practice. Respondent’s age, practice type, oncology fellowship training, the number of CaP patients newly diagnosed per month, and the number of years in urol-ogy practice were used in regression analysis. Odds ratio (OR) with 95% confidence interval were calculated, and sta-tistical significance was defined as P < 0.05.
3.1. Respondent characteristics
Characteristics of 425 survey respondents
No. of patients seen monthly with newly diagnosed prostate cancer
nonfellowship trained physicians (29.2% vs. 21.8, P = 0.09). Furthermore, the majority of physicians who Clozapine-N oxide employed FT were in clinical practice for greater than 15 years (76.7% vs. 23.3%, P = 0.005). While the most common setting for utilization of FT was in patients with unilateral intermediate risk CaP (72.8%), a minor percent-age of respondents also used FT for patients with bilateral intermediate-risk and unilateral high-risk CaP (10.6% and 21.3%, respectively; Fig. 1). Majority respondents preferred to use multiparametric MRI (mp-MRI) to identify candi-dates for FT. mp-MRI was used either with systemic trans-rectal ultrasound (TRUS) biopsy (32%) or MRI-TRUS fusion biopsy (32%).
The most common FT modality used by physicians was cryoablation (56%) followed by high-intensity focused ultrasound (HIFU) (44.6%; Fig. 1). Urinary retention and erectile dysfunction were the 2 most common postoperative complications reported by the 67% and 28% of the respond-ents (Fig. 1). Among respondents who do not utilize FT, 3 most common reasons for not using FT were the lack of belief in "index lesion theory" (63%) followed by the lack of experience (41.4%) and lack in the belief of its efficacy (41.1%; Fig. 1).
3.2. Survey responses
Participants’ responses to survey questions are presented in Table 2. Half of the respondents believed FT to be at least moderately beneficial for the treatment of localized CaP. Academic urologists were more likely to consider FT beneficial (59% vs. 44%, P = 0.034). Fellowship training or the number of years in urology practice had no relation to believing how beneficial FT was (P = 0.183 and P = 0.934, respectively).
In total, 45% of participants believed in the index lesion theory. Urologists in the academic setting were more likely to believe in the index lesion theory (53.8% vs. 38.6%, P = 0.002). There was no significant difference in the belief in index lesion theory among urologic oncology fellowship trained individuals and nonfellowship trained individuals (46% vs. 44.5%, P = 0.830). Furthermore, US-based physi-cians were less inclined to believe the index lesion theory (40.8% vs. 50.7%, P = 0.04) than the overseas physicians.
Overall, 24% participants utilized FT in their practice (Table 2). Not surprisingly, respondents who believed in the index theory tended to utilize FT more than skeptics of the theory (40.1% vs. 11.2%, P < 0.001). There was no sig-nificant difference in FT utilization among academic or nonacademic physicians (26.9% vs. 21.9%, P = 0.23). Urol-ogists who were fellowship trained in oncology were slightly more inclined to utilize FT compared with 3.3. Prediction of focal therapy use
The results of the logistic regression analyses are shown in Table 3. On both univariate and multivariate logistic regression, physician’s experience (more than 15 years in urology practice; OR 2.43 [1.11−5.26], P = 0.025) and see-ing more than 10 patients with new CaP diagnosis per month (OR 2.32 [1.36−3.94], P = 0.002) were independent predictors of FT utilization for localized CaP in practice.
Lastly, more than half of the respondents (57.8%) indi-cated that they would utilize FT more often if they had access to reliable and cost-effective methods. Furthermore, 52% of respondents believed that using navigation and treatment planning tools would improve FT outcomes.
Numerous studies have established that the majority of CaP cases are multifocal in origin [12−16]. The multifocal-ity concept is the biggest obstacle to the implementation of FT. However, as described earlier, there is evidence that “index lesion” characteristics can predict the oncological outcomes (index lesion theory) [17,18]. Ohori et al. ascer-tained "index lesion" makes up for up to 80% of the cancer burden . More recently, Liu et al. from Johns Hopkins, implementing copy number analysis, proposed a monoclo-nal origin of lethal metastatic CaP . Interestingly in our survey, overall 45% of physicians believed in the “index lesion” theory. Based on the evolving index lesion theory, FT is currently increasingly used and evaluated in the uro-logic oncology world. It will be exciting to see “index lesion” theory development in the future.