Stesura Seveso Archivio Italiano di Urologia e Andrologia 2022; 94, 4406 ORIGINAL PAPER No conflict of interest declared. INTRODUCTION Currently whole-gland therapy such as radical prostatecto- my (RP) and external beam radiotherapy (EBRT) still rep- resent the gold standard treatments for localized prostate cancer (PCa). Both treatments are effective but they can be burdened with procedure-related side effects such as uri- nary incontinence and erectile dysfunction (1, 2). Nowadays there are well-established studies in support of prostate-sparing procedures in low-risk cancer, but the treatment indications have also expanded to small inter- mediate-risk and high-risk tumours, which are consid- ered life-threatening (3-5). Concerns have arisen about the focal treatment of a disease that has been found to be multifocal in 50-76% of patients (6). A high degree of genomic heterogeneity and a 13-26% Gleason Score heterogeneity have also been reported, even within the positive cores of prostate biopsy (7, 8). In a therapeutic approach for PCa the concept of index lesion is therefore decisive. Despite the multifocality and heterogeneous disease pattern inside the same gland, the index lesion represents the largest prostatic tumour with the highest histologic grade within the prostate. This is likely to drive the biology of the patient’s disease. In fact, the same genomic sequence has been found in metastatic lesions and in the index lesion within the prostate (9). Interestingly, despite being limited to one case, Haffner et al. used the whole-genome sequencing and molecular analyses to characterize the lethal clone in a patient who died of PCa. Surprisingly, the lethal clone arose from a small, relatively low-grade cancer focus in the primary tumour. These findings highlighted le potential impor- tance of investigate molecular prognostic and/or predic- tive markers to optimize the pathological evaluation and delineate clonal heterogeneity (10). Laser interstitial thermotherapy performed by the diode multichannel laser system EchoLaser X4 is a transperineal percutaneous procedure named SoracteLiteTM that uses laser light transmitted through optical fibres to produce irreversible thermal damage of target tissue. The EchoLaser X4 system allows multifibre ablation man- agement and provides planning software for optimization Background: The aim of this study was to evaluate the outcomes of patients suffering prostate cancer (PCa) treated conservatively using 1064 nm laser energy for focal laser ablation (FLA). The patients includ- ed in the study were unsuitable for surgery or unwilling to receive external beam radiotherapy because they were afraid of the possible side effects of whole-gland therapies. Methods: This study included patients with a diagnosis of non- metastatic PCa who underwent FLA using SoracteLiteTM system. Tissue ablation was performed at a fixed power of 5 W by the diode multichannel laser system EchoLaser X4 that uses laser light transmitted through optical fibres causing the target tissue to undergo irreversible thermal damage. Functional outcomes were evaluated with the International Prostatic Symptoms Score (IPSS) and 5-item version of the International Index of Erectile Function (IIEF-5) before the treatment and one year later. Results: Ten patients suffering non-metastatic PCa were includ- ed. Four decided upon a conservative treatment because of reduced performance status and for six patients the procedure was chosen electively. All patients underwent multiparametric magnetic resonance imaging at 3 and 12 months and eight out of ten patients underwent prostate biopsy at 6 months. Persistent disease was detected in 3 patients who underwent a second ablation. In these patients at the biopsy following the second ablation none harbored residual disease. At follow-up, no patient suffered urinary incontinence requiring the use of pads. No significant worsening in sexual potency measured with IIEF-5 (p = 0.356) or prostatic symptoms measured at IPSS (p = 0.462) were recorded comparing pre-treatment condition vs one-year follow-up. Compared with baseline, prostate-specific antigen was significantly reduced at one-year follow-up (3.7 ± 1.1 vs 7.9 ± 4.1 ng/mL; p = 0.008). Conclusions: Although whole gland therapies remain the gold standard treatment for PCa, our results indicate that the SoracteLiteTM system for focal laser ablation, as a very preliminary step, appears to offer a short-term oncologic control of PCa with negligible side effects. KEY WORDS: Focal laser ablation; Focal therapy; Prostate cancer; Prostate magnetic resonance imaging; Transperineal treatment. Submitted 10 September 2022; Accepted 23 October 2022 A single-operator experience using EchoLaser SoracteLiteTM for focal laser ablation of prostate cancer: One more arrow in the quiver for the conservative management of the disease Iacopo Meneghetti 1, Demostene Giardino 2, Riccardo Morganti 3, Vincenzo Marino 2, Filippo Menchini Fabris 2, Riccardo Bartoletti 4, Novello Pinzi 2 1 Urology Department, Ospedale Apuane, Massa, Italy; 2 Surgery Unit, Casa di Cura San Rossore, Pisa, Italy; 3 Section of Statistics, University of Pisa, Pisa, Italy; 4 Urology Department, University of Pisa, Pisa, Italy. DOI: 10.4081/aiua.2022.4.406 Summary 407Archivio Italiano di Urologia e Andrologia 2022; 94, 4 EchoLaser SoracteLiteTM for focal laser ablation of prostate cancer of the ablation strategy. It also supports the surgeon with planning for effective and safe needle positioning with respect to the tumour and critical structures to be spared. Here, we present the results obtained from our updated single-surgeon prospective cohort of 10 patients with at least one-year follow-up after the use of 1064 nm laser energy for focal laser ablation (FLA) of PCa. In this cohort we treated patients with only one lesion so as not to have to decide whether to treat the index lesion or also the other/s considered less aggressive/s. MATERIALS AND METHODS Population characteristics Between October 2019 and October 2020, 10 patients candidate to organ-sparing treatment for PCa were select- ed to undergo FLA using the SoracteLiteTM procedure. SoracteLiteTM for FLA treatment was offered to patients with no metastatic PCa, Gleason score ≤ 8, TNM stage T1c-T2cN0M0, prostate-specific antigen (PSA) ≤ 20 ng/mL, a single lesion with a concordant multiparametric magnetic resonance imaging (mpMRI), a tumour volume ≤ 20 mL and a good life expectancy. All patients included in this study had a prostate volume smaller than 65 mL. The patients included in the study were unsuitable for sur- gery or unwilling to receive EBRT. It was fully explained to the patients that different focal therapies validated were available, but the patients, due to the trust acquired with our working group, choose the aforementioned approach that was presented as experi- mental. Each case had been previously discussed in a multidisciplinary meeting and extensively with the patient, who received written information on the benefits and risks of the procedure. Prior to the start of patient recruitment, the surgeon (NP) followed a training program, visiting centres with expertise in FLA with SoracteLiteTM technology to achieve proficien- cy in the main aspects of FLA (fibre positioning, energy dose, ablation strategy and ablation margin). Finally, a rep- resentative from the manufacturer of the device trained the surgeon and operating theatre staff on the use of SoracteLiteTM, and assisted the operator for the first 3 cases. Protocol and assessment of data The study was performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. The confidentiality of patient data was guaranteed as the patients were entered into a database in the form of a number. Following Institutional Review Board Commitee approval and registration of the protocol (0014161/2019), patients with localized PCa were prospectively recruited. The informed consent was obtained from all patients for the use of their data. Pre-operative assessment All the patients we followed had undergone mpMRI and transperineal prostate biopsy with systematic sampling of the prostate with 12 samples per side for a total minimum of 24 samples. Six out of 10 patients underwent biopsy before the mpMRI, in the other 4 mpMRI was done before the biopsy. In those patients in whom a mpMRI was performed before the biopsy, two more samples were taken, targeted, as cognitive biopsy, in the area identified on mpMRI. The inclusion of random samples was funda- mental for us to exclude the presence of disease in areas not frankly suspicious on mpMRI. We classified these patients as carriers of single lesion disease inasmuch the positive biopsy samples were found only in the area high- lighted as suspicious on mpMRI. All patients had under- gone systematic PSA testing prior to diagnostic biopsy. In addition, a questionnaire for the evaluation of urinary symptoms and sexual function were administered to the patients before undertaking the therapeutic treatment. Technique SoracteLiteTM for FLA consists of ultrasound-guided posi- tioning of up to 4 applicators (depending on the tumour volume and shape) consisting of a 21-gauge Chiba needle (INTRODUCER, Elesta SpA, Calenzano, Italy) in whose lumen is inserted a 272-μm quartz optic fibre (Fiber Optic for PLA, Elesta SpA, Calenzano, Italy). The fibre tip pro- trudes 10 mm from the introducer tip. The optic fibres are connected to a multisource laser system operating at 1064 nm (EchoLaser X4, ELESTA SpA, Calenzano, Italy). Each treatment is performed at a fixed power of 5 W, with the single illumination dose determined on a case- by-case basis according to the tumour size. Additional laser fibres can be placed within the tumour volume at a mutual distance ranging from 5 to 10 mm in order to amplify the volume of necrosis obtained by simultaneous tissue irradiation and summative volumetric necrosis. Depending on the tumour size in the longitudinal direc- tion, one or more consecutive illuminations are performed with a ‘pull-back’ technique (retraction of the needle-fibre kit by 5-10 mm) during the same treatment session. For the same duration of illumination and dose of energy adminis- tered, the thermoablated area is always reproducible regardless of tissue properties and vascularity. The anato- mopathological study of a thermoablated tissue area showed that the necrotic area assumes an ellipsoid shape. The treatment ends when the total planned dose is deliv- ered. A single illumination dose ranges from 1200 J to 1800 J, which corresponds to an illumination time of 4 to 6 minutes. In cases where a ‘pull-back’ maneuver is used, the illumination time doubles. A touch panel device (ESI, EchoLaser Smart Interface, Elesta SpA, Calenzano, Italy) can be connected to the auxiliary video output of a general ultrasound scanner and used for treatment planning. ESI has a dedicated planning software that allows the visualization of needles insertion trajectories of the needle guide mounted on the US biplanar probe of the connected ultrasound. This facilitates the insertion of regularly spaced multiple parallel needles simultaneously. The treatment planning is crucial for the outcome of the treatment. The ESI superimposes on the ultrasound image a graphical representation, consisting of guidelines for the needle trajectories and the depiction of two concentric closed perimeters, an external one for the size of safety dis- tances and an internal one for the size of the ablation area. The size and position of both of these perimeters depend on the treatment parameters (dose, number of fibres, ‘pull- back’) and the surgeon can simulate the best treatment strat- egy before needle insertion. The planning ends when the Archivio Italiano di Urologia e Andrologia 2022; 94, 4 I. Meneghetti, D. Giardino, R. Morganti, V. Marino, F. Menchini Fabris, R. Bartoletti, N. Pinzi 408 tumour is visualized within the internal closed perimeter and all critical structures (urethra, vascular bundle, sphinc- ters, bladder wall and rectum) are located outside the exter- nal perimeter. If required, it is possible to increase the dis- tance from the rectum by injecting a 33% (w/v) glucose solution between the prostate and the rectum. The goal of the planning phase of the procedure is to identify the point where the tip of the needle will be located, with respect to the area that will be ablated. The ultrasound software asso- ciated with a directional template for guidance allows the placement of the laser fiber(s) in the index lesion with mil- limeter precision (Figure 1). After an observation period of about one hour, a tran- srectal contrast enhanced ultrasonography to evaluate the extent of the coagulation zone is performed. Patients are discharged the day of the procedure without a catheter. Follow-up, functional and oncological outcomes All patients were advised to undergo a 6-monthly biopsy sampling, and mpMRI at 3 and 12 months. Complete response was defined on the basis of negative imaging study results and negative prostate biopsy at 6 months. Persistent disease was defined as the presence of suspected or positive imaging study results and/or posi- tive prostate biopsy performed at 6 months. In case of persistent disease, a second ablation was planned. The International Prostatic Symptoms Score (IPSS) and 5-item version of the International Index of Erectile Function (IIEF-5) were completed by each patient prior to the procedure and at 1-year follow-up without changing the intake of any type of drug. PSA was also confronted before treatment and at one-year follow-up. Intraoperative and postoperative complications were recorded according to Satava (11) and Clavien-Dindo (12), respectively. Statistical analysis Categorical data were described by frequency; continuous data were expressed as mean and standard deviation. To compare data (IPSS, IIEF-5 and PSA) measured at base- line and after 12 months of follow-up, t-tests for paired data were applied. Statistical significance was set at p < 0.05 and all analyses were carried out with SPSS Statistics version 27.0 (IBM Corp., Armonk, NY). RESULTS Patient characteristics are summarised in Table 1. A total of 10 patients suffering non-metastatic PCa were includ- ed in the present study. FLA for PCa was selected as the initial treatment for the following reasons: reduced per- formance status (4 patients) and patient’s own choice (6 patients). At the diagnostic biopsy four patients suffered PCa Gleason 6 (3+3), two patients had Gleason 7 (3+4) Table 1. Patient characteristics. Patient number Age (years) Indication for FLA DRE PSA (ng/mL) GS Laterality Diameter of tumour at mpMRI (mm) PSA (ng/mL) (12 mo) 1 65 Elective + 7.3 6 Right 5 3.2 2 73 Elective - 5.1 6 Left 14 3.1 3 60 Elective - 5.1 6 Left 7 3.9 4 67 Unfit for surgery + 11 7 (4+3) Right 20 1.5 5 75 Elective - 5.2 8 (4+4) Left 9 3.6 6 69 Elective + 5.7 7 (3+4) Left 10 3.2 7 74 Unfit for surgery + 17.8 7 (4+3) Right 15 5 8 78 Elective + 10.1 7 (3+4) Right 15 5.2 9 73 Unfit for surgery - 6.8 7 (4+3) Left 11 4.1 10 70 Unfit for surgery + 4.9 6 Left 7 3.9 +: Suspicious. -: Non-suspicious. DRE: Digital rectal examination. FLA: Focal laser ablation. GS: Gleason Score. mpMRI: Multiparametric magnetic resonance imaging. PSA: Prostate-specific antigen. Figure 1. On the left: EchoLaser Smart Interface settings during the planning phase. The ablation area (dotted magenta line) is simulated in order to define the best approach in terms of number of fibres, mutual tip position, ‘pull- back’ and energy dose. The external circle (dotted cyan line) represents the safety distance to be assured with respect to critical structures (nerves, rectum). On the right: two introducer needles are positioned in a parallel orientation according to the planning. 409Archivio Italiano di Urologia e Andrologia 2022; 94, 4 EchoLaser SoracteLiteTM for focal laser ablation of prostate cancer and three Gleason 7 (4+3). Only one patient presented a Gleason 8 (4+4) disease. All patients underwent mpMRI at 3 and 12 months (Figure 2). Eight out of ten patients underwent prostate biopsy at 6 months. Six patients in which the mpMRI did not highlight suspected lesions (PI-RADS category < 3) had negative biopsy results accord- ing to the scheme (12 samples per side with the addition of sampling in the area previously subjected to FLA). These patients were considered to have a complete response to treat- ment. Three patients had a persistent disease according to positive (PI- RADS category ≥ 3) mpRMI at 3 months. Two of them underwent a prostate biopsy according to the scheme with additional samplings in the suspected area. The pathology report revealed that those two patients still harbored PCa. One of them refused to undergo prostate biopsy and agreed to directly receive a second treatment in the area of persistence of disease identified on mpMRI (PI- RADS category 5). The diagram in Figure 3 summarizes the diagnostic-ther- apeutic process of the entire cohort of patients in our study. The three aforementioned patients with persistent disease underwent a second ablation and at 12 months, mpMRI revealed no lesions with PI-RADS category > 3. All three patients underwent a transperineal prostate biopsy at 12 months that was negative for PCa. All the patients who required a second ablation had a dis- ease > 10 mm at the first mpMRI. Two patients were unwilling to repeat the biopsy at 6 months. One of them was the aforementioned patient who received directly a second treatment, the other one underwent a mpMRI at 6 and 12 months. In the latter patient, a PI-RADS category 2 was found in the ablated area at mpMRI, compatible with a necrotic area. No complications related to diagnostic prostate biopsies were reported. No patient developed extracapsular inva- sion (> cT3) or appearance of bone lesions or lymph node swellings (> 1 cm) in the fields of inclusion on any mpMRI pelvic scan performed for primary diagnosis or follow-up at 6 months or 1 year. No intraoperative com- plications were recorded according to the Satava classifi- cation system (11). Postoperatively four patients required analgesic drugs (Clavien-Dindo grade I). At 1-year follow-up, no patient suffered urinary inconti- nence that required the use of pads. Compared with base- line, no significant worsening in functional outcomes at 1 year was observed as measured with the IIEF-5 (p = 0.356) and IPSS (p = 0.462) (Table 2). Table 2. PSA (ng/ml), IPSS and IIEF-5 levels at baseline and after 12 months. Factor Mean (SD) p-value PSA pre-treatment 7.9 (4.1) 0.008 PSA at 1 year follow-up 3.7 (1.1) IPSS pre-treatment 6.9 (3.1) 0.462 IPSS at 1 year follow-up 7.3 (4.1) IIEF-5 pre-treatment 11.1 (5.1) 0.356 IIEF-5 at 1 year follow-up 10.2 (6.7) IIEF: International Index of Erectile Function. IPSS: International Prostate Symptoms Score. PSA: Prostate-specific antigen. Figure 2. On the left: mpMRI T2-weighted sequences on the axial view showing a 7 mm carcinoma located in the left apical portion (arrowhead) in a 53-year-old patient before treatment. On the right: the same patient at 3-month follow-up after transperineal FLA. A hypointense area compatible with necrotic-coagulative necrosis (arrowhead) matching the previous tumoural area is visible on the mpMRI T2- weighted image. Figure 3. Diagnostic-therapeutic process of the entire cohort of the 10 patients included in our study at follow-up. Archivio Italiano di Urologia e Andrologia 2022; 94, 4 I. Meneghetti, D. Giardino, R. Morganti, V. Marino, F. Menchini Fabris, R. Bartoletti, N. Pinzi 410 At 1 year follow-up, mean ± SD PSA was significantly reduced relative to baseline (3.7 ± 1.1 vs 7.9 ± 4.1 ng/mL; p = 0.008) (Table 1, Table 2 and Figure 4). DISCUSSION Conservative treatments aim to control the disease while minimizing the risk of developing side effects, primarily sexual impotence, urinary incontinence and bowel toxic- ity. In fact, the possibility to treat only a targeted part of the gland reduces the risk of damage to the neurovascu- lar bundles, external urethral sphincter, bladder neck or rectum. Our results regarding lower urinary tract symptoms (LUTS) and sexual function measured with IPSS and IIEF-5 did not demonstrate a statistically significant change one year after the treatment (p = 0.462 and p = 0.356 vs baseline, respec- tively). Our results are in agreement with Eggener et al., who found no worsening of IPSS symptoms in FLA-treated patients. Interestingly, however, these investi- gators found a worsening of sexual function at 1 month (p = 0.03) and 3 months (p = 0.05), although the difference vs baseline was not significant at 12 months (p = 0.38) (13). Also van Riel et al. found a worsening of sex- ual function at 1 week after the procedure, although the difference vs baseline was not significant at 1 month (14). Moreover, Chao et al. in their experience using FLA for localized PCa found no adverse impact on LUTS or sexual function at 1 year (15). The presence of an expert technician for the device alongside the surgeon during the first cases is essential to reduce the initial learning curve and thus to improve safety of the procedure (16). Regarding the learning curve in using SoracteLiteTM, we believe that it is comparable to the training required for transperineal prostate biopsy, so that in the hands of an expert urologist, the use of the SoracteLiteTM procedure is quite simple. Another strength of our study is the fact that all the procedures were performed by a sin- gle operator with extensive experience of the transperineal approach, and without the potential confounder of inter-operator dif- ferences. The urologist (NP) who performed all the procedures in our study had extensive experience in performing transperineal prostate biopsies. To date, it is far more common to perform prostate biopsies via the transrectal access (17), so for the urologist who approaches the use of SoracteLiteTM for FLA it would be advisable to first acquire some biopsy experience with a transperineal access before engaging in ablative treatment. We believe that for the urologist experienced in transperineal access, three procedures are sufficient to complete the learning process and carry out adequate treatments. Although our results and the overall literature are too pre- liminary to determine with adequate accuracy any possi- ble advantage or disadvantage regarding the use of SoracteLiteTM for the treatment of PCa, we believe that an extraordinary advantage of the method is the ability to evaluate one hour later the effect on the tissue and to be able, in the same session, to expand the ablation in the desired area if this is not satisfactory (Figure 5). Figure 4. Ladder plot illustrating individual changes in PSA from pre-treatment (at baseline) to post-treatment (12 months). Figure 5. On the left: transverse ultrasound image during ablation. On the right: longitudinal ultrasound image of the same tumour during ablation phase. Coagulated tissue appears as a hypoechoic area overlapped by gas artefacts (arrowhead). 411Archivio Italiano di Urologia e Andrologia 2022; 94, 4 EchoLaser SoracteLiteTM for focal laser ablation of prostate cancer Similar to other authors who have approached PCa with focal therapy for PCa, no patient in our cohort needed pads or complained of urinary incontinence after the treatment (18). This represents an outstanding success, as incontinence is statistically the most bothersome side effect of RP with an incidence that in some series reaches 65% (19). Even approaches such as EBRT or brachyther- apy, which are considered less invasive, are burdened with considerable rates of worsening of urinary obstruc- tion, irritation and worsened bowel symptoms (2). One year after the procedure, a statistically significant reduction in PSA was observed compared with baseline (p = 0.008). Although three of the patients who had resid- ual disease at 6 months prostate biopsy underwent a sec- ond ablation before 12 months, a reduction in PSA was evi- dent for each patient in our cohort (Figure 4). In contrast to our results, Chao et al., reporting oncological and func- tional outcomes for 34 men who had undergone FLA for PCa, found that PSA was a poor discriminator of disease recurrence in the ablated zone at two-year follow-up (15). None of our patients had a PSA > 20 ng/mL at diagnosis, which, as a single factor for D'Amico's criteria, would place the case into a high-risk category. While there is no clear indication on the use of both PSA and PSA-density as eligibility criteria for FLA (20), it is often suggested to consider PSA ≤ 15 ng/mL as a limit for a patient's suit- ability for focal therapy (21). The only patient who pre- sented with Gleason Score 8 disease was a patient who wished to undergo some kind of treatment but was con- sidered unsuitable for other therapeutic treatments because of age and comorbidities. In three patients, disease was persistent after the first FLA procedure and in all three cases the disease was present in the same area at follow-up. This is likely related to inaccuracy in pinpointing the entire lesion during the first procedure. Our results suggest that the treatment of lesions > 10 mm could be less accurate and require a sec- ond-look. The disadvantage of not achieving complete disease ablation at the first attempt, especially in more aggressive diseases, could potentially give the disease the chance to progress. In a study of ultrasound-guided laser ablation in the thy- roid gland of a porcine model, Ridouani et al. concluded that 3 W/1800 J was the optimal setting to obtain a coag- ulated necrotic zone of 10 mm with 2 mm margin when utilizing a single needle (22). In our cohort of patients, the energies used were greater and for a single treatment were not lower than 5 W/3600 J. Other clinicians who used the SoracteLiteTM system for benign prostatic hyperplasia used a power of 3W for tissue ablation (23). We chose to use greater ablation power for tumour tissue with the aim of greater certainty in disease ablation. In fact, higher powers reduce the duration of the initial phase of heating which can be affected by local tis- sue properties, and therefore trigger the ablation phase very quickly. This leads to lower interpatient variability of treatment outcomes. In the case of larger lesions, depend- ing on the tumour shape with respect to the needle inser- tion direction, a ‘pull-back’ maneuver was carried out (nee- dle retraction and second energy dose delivery) or a second fibre was placed in a parallel way with respect to the first one and simultaneous energy delivery was performed. There are some limitations to our study. Firstly, the small number of patients limits the robustness of our results, especially those concerning cancer control. Secondly, fol- low-up in this study was limited to one year. Therefore, while our data on functional outcome are interesting, the oncological results still need to be validated with a longer follow-up. Finally, our data are not sufficient by themselves to for- mulate an indication for SoracteLite FLA in PCa, especial- ly since this is a non-randomized series without a strict exclusion criterion for class of risk. Our study highlights important opportunities for future work. 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Correspondence Iacopo Meneghetti, MD (Corresponding Author) iacopo.meneghetti@tiscali.it Urology Department, Ospedale Apuane, Massa (Italy) Demostene Giardino, MD demosteneg@libero.it Vincenzo Marino, MD vincenzo_mar@tiscali.it Filippo Menchini Fabris, MD menchinifabris@andrologia.it Novello Pinzi, MD pinzinovello@gmail.com Surgery Unit, Casa di Cura San Rossore, Pisa (Italy) Riccardo Morganti, MD r.morganti@ao-pisa.toscana.it Section of Statistics, University of Pisa, Pisa (Italy) Riccardo Bartoletti, MD riccardo.bartoletti@unipi.it Urology Department, University of Pisa, Pisa (Italy)