One of our aims in this study was to assess the amount of tissue acquisition and diagnostic accuracy by EUS-FNA biopsy in pancreatic lesions. The compatibility of EUS-FNA PBS-PS categories with final clinical diagnosis or histopathology was quite high and parallel to the literature . Discordancy with final diagnoses was observed in 7 of 128 cases with EUS-FNA cytology. ROSE was not available for 3 of the 7 patients. In a 57-year-old male patient who showed clinical discordancy and whose cytology was given category-II (non-ROSE), dense lymphocytes and histiocytes and a small number of ductal epithelial cells in cytology materials were evaluated in favor of chronic pancreatitis and malignancy could not be excluded. The final diagnosis was accepted as malignancy during the clinical follow-up and patient received chemotherapy. Another 49-year-old male patient with category-II PBS-PS, cytology had degenerated epithelial cells. This patient had ROSE, however because of high clinical suspicion of malignancy, a second EUS-FNA biopsy was performed. The second biopsy resulted as category-V and the patient was treated as adenocarcinoma. 67-year-old female was diagnosed as category-II instead of non-diagnostic category because of the observed, even if, small number of honeycomb epithelial cells. This patient with extensive metastases was diagnosed with pancreato-biliary adenocarcinoma by liver tru-cut biopsy. A 54-year-old male patient had a history of chronic pancreatitis and walled of necrosis, was diagnosed as category-III. It was interpreted as possible reactive findings due to the low number of atypical cells observed. Again, in the cytological materials of three patients-were diagnosed as category IVb- with discordant diagnosis, diffuse mucin, anisochoric, increased nucleus size, and atypical epithelial cells were present. The final diagnoses of these patients during follow-up were pancreatic cancer, high-grade PANIN, and pancreatic adenocarcinoma, and all were diagnosed pathologically with Whipple materials.
Studies have focused mainly on solid lesions of the pancreas and report conflicting results about the effect of ROSE on diagnostic accuracy . To a lesser extent, ROSE for cystic lesions of the pancreas has not been shown to have a significant effect on diagnostic accuracy, and there are even some studies emphasizing that ROSE should not be performed on cystic lesions . In this study, we showed that the availability of ROSE in case of solid lesions is associated with higher diagnostic ability and diagnostic accuracy than cystic lesions. Also, if a cystic lesion contained a solid component, diagnostic ability was positively affected compared to pure cystic ones. However, evaluation of pure cystic lesions in our study showed that ROSE had no effect on diagnostic ability. There are some data in the literature that the demographic characteristics of the patients and the location of the lesions in the pancreas do not affect ROSE . Also; in this study, patient's age, size of the lesions, and distribution of the lesion did not differ with availability of ROSE.
Another purpose of our study was to evaluate the necessity of using ROSE. Since, the need for ROSE for adequate tissue acquisition with EUS-FNA biopsy still remains as one of the most discussed issues in practice. In centers where it is possible, ROSE can provide the additional material needed in difficult situations and thus provide suitable material for histological evaluation that will combine the benefits of cytology and histology. Iglesias-Garcia et al. showed that the presence of ROSE was associated with significantly fewer passes, fewer scant samples, higher diagnostic yield, and higher diagnostic accuracy for malignancy . Furthermore, Klapman et al. compared the EUS-FNA cytology results obtained by the same endosonographer at two centers, with and without ROSE. The diagnostic yield (regarding malignancy) was higher when a cytopathologist was present (58% vs 41.5%; P:0.006), with a lower number of inadequate tissue specimens (9% vs 20%; P: 0.035) . However, on the contrary, Wani et al. compared the diagnostic yield and proportion of inadequate specimens undergoing EUS-FNA of pancreatic masses with (n : 121) and without (n : 120) ROSE. There was no difference between groups in the diagnostic yield regarding malignancy (with ROSE 75.2% vs without ROSE 71.7%; P: 0.53) and proportion of inadequate specimens (9.9% vs 13.3%; P:0.4). Procedures with ROSE had significantly lower numbers of passes (3.7 vs 7; P <0.001). There were no significant differences between groups with regard to overall procedure time, adverse events, number of repeat procedures, and cytologic characteristics of specimens . Wani et al. in another review stated that, the use of ROSE does not impact the diagnostic yield for malignancy and the number of inadequate specimens, based on the available evidence. Therefore, they recommended that ROSE should be used in centers that have difficulty in achieving tissue adequacy .
In this respect, the necessity of ROSE procedure is still controversial . Some large centers do not use ROSE due to loss of time, human resources and workforce; but some studies continue to emphasize the superiority of ROSE [3,5]. The diagnostic accuracy of EUS-guided tissue acquisition under ROSE is reported to be higher than 90% in most studies; however, comparable results have also been reported from some trials without ROSE [13,17]. In one recent meta-analysis, authors found that there was no indication that the application of ROSE improved the diagnostic yield (risk difference [RD], 0.04; 95% CI, 0.05 to 0.13) . In addition to these discussions, in this study, it was shown that ROSE had a significant advantage over the non-ROSE in 128 cases with diagnostic results in the first EUS-FNA biopsies. However, although the ROSE procedure was found to be significant in terms of yielding diagnostic results, the final diagnostic accuracy of the cases with ROSE was not significantly different from those without ROSE.
Lisotti A. et al. in their study, when EUS-FNA biopsy diagnoses and final diagnostic results were compared in cases with and without ROSE; performing with ROSE had a higher pooled sensitivity with similar pooled specificity; in particular, sensitivity and specificity were 83% (95% CI, 64%-93%) and 98% (95% CI, 80%-100%) when ROSE was present, respectively, as compared with 65% (95% CI) , 57%-73%) and 94% (95% CI, 31%-100%) when ROSE was not available . However, Fabbri et al. in his study, when 333 pancreatic solid lesions were divided into ROSE and non-ROSE, no significant difference in sensitivity, specificity, positive and negative likelihood ratios, and diagnostic accuracy was found between the two study groups . In addition, some studies have shown that ROSE's success in providing diagnostic results is insufficient even if it is applied in non-diagnostic cases . In our study, in 34 non-diagnostic cases, no significant difference was observed in the success of acquiring final diagnostic results between those who underwent ROSE and those who didn’t.
Tissue acquisition with ROSE can also contribute to the pathologist in terms of the number of passes, slide smearing and cell blocks. In this study, the amount of tissue acquired with ROSE (number of slides, cell blocks) was found to be significantly superior than those without ROSE. The reason for this may be the intervention of the cytopathologist/ pathologist/ cytology technician who qualifies the cytological material that is insufficient during ROSE, increasing the number of passes and the manipulation for obtaining tissue, also spreading the tissue to the slides and forming the appropriate cell block. The advantages of obtaining a cell block, especially with fine needle aspiration, are being able to see the lesion pattern, performing immunohistochemical staining to support the diagnosis, and acquirement of tissue for molecular analysis, even contributing to the chemotherapy regimen and molecular target therapy .
Studies report that the needle type used and macroscopic on-site evaluation by the endoscopist increase the quality and tissue acquisition and thus success in acquiring cell block . Although white, yellowish-colored biopsy material of appropriate thickness helps to acquire more cells and to show the pattern and architecture of the lesion, the effect of making a slide smear in excluding differential diagnoses and reaching a definitive diagnosis cannot be ignored [4,13,21]. Adequate slide number and presence of cell block may be sufficient to make a definitive diagnosis without the need for a second interventional procedure. In addition, it is very critical for the patient that the cell block can provide the tissue for auxiliary immunohistochemical techniques and molecular tests .
There are studies in the literature to optimize the effectiveness of needle type, number of passes, smearing slide techniques and cell block acquisition in ROSE [5,6]. Erickson et al. in their study, stated that the number of passes should be between 3 and 6 in order to obtain high diagnostic accuracy with ROSE during the FNA procedure to the pancreas . Furthermore, Chung et al. in their multicenter study, they suggested 4 as the optimum number of passes to be applied in centers that do not use ROSE in Korea . Mizutani et al. demonstrated the contribution of the cell block acquirement in their study to make the definitive diagnosis, in terms of the applicability of ancillary tests and molecular studies . Therefore, even a single cell block from the lesion can be very valuable, increasing the sensitivity and specificity for accurate diagnosis. In addition to all these, although there are studies on the optimization of the obtained cytological material with the slide smear technique, but, the optimum "number of slide smearing" requiring for a diagnostic ability has not been sufficiently examined in the literature for both ROSE and non-ROSE applications.
In our study, the application of ROSE in diagnostic cases was significantly higher than those who didn’t have ROSE in terms of the number of passes, slides, and cell blocks. However, in cases with ROSE, the diagnostic cases was not different than non-diagnostic ones regarding the number of passes, slides and cell blocks. ROSE was independently associated with diagnostic ability in regression analysis, which can be interpreted as follows: 1) Although there is a pathologist at the bedside, it may not have sufficiently increased the number of passes and thus the tissue acquisition in non-diagnostic cases. In addition, 2) slides and cell blocks may have been prepared technically improperly, and it may have caused degeneration of cells and tissues with artefactual changes. This could have prevented giving diagnostic competence. 3) If the possibility of complications is high in patients who have undergone intervention, the number of passes may be reduced.