O-P02 A fast-track surgery programme leads to timelier treatment and higher resection rates in pancreatic cancer

Background Pancreatic cancer is currently the fourth most common cause of cancer-related mortality in the economically developed world and is set to become the second most common cause of cancer-related mortality within the next few years. NICE guidance makes a strong recommendation to offer up-front surgery to people with resectable pancreatic cancer, without preoperative biliary drainage, if sufficiently fit for surgery. The aim of this study was to perform a propensity-matched comparison of patients with pancreatic cancer undergoing surgery, with and without biliary stenting, to examine perioperative outcomes and to perform an intention to treat analysis to evaluate long-term survival between the two groups. Methods This was an observational study of a cohort of consecutive patients presenting with obstructive jaundice and undergoing pancreatoduodenectomy for pancreatic and periampullary malignancies between November 2015 and May 2019. Data related to patient and tumour characteristics, biliary drainage, surgery and histopathology were gathered and analysed from a prospectively maintained electronic database. Post-operative complications were defined and graded according to the definitions of the International Study Group on Pancreatic Surgery (ISGPS) and the Clavien-Dindo system. Data related to adjuvant treatment, disease recurrence and overall survival were also analysed. Results In this retrospective study of 216 consecutive operable patients, 70 followed the fast-track (FT) pathway and 146 had pre-operative biliary drainage (PBD). All 70 patients in the fast-track group and 122 out of 146 in the PBD group proceeded to surgery (100% and 83.6% respectively, p = 0.001). Interval time from diagnostic CT scan to surgery and from MDT decision to treat to surgery was much shorter in the FT group (median range) 8 vs 43 days p < 0.001 and 3 vs 36 days p < 0.001 respectively) as was the overall time from diagnostic CT to adjuvant treatment (88 vs 121 days p < 0.001). Postoperative outcomes including in-hospital stay, number and grading of complications, readmission rate and mortality rates were comparable in the two groups. There was no difference in survival between the two groups. Conclusions These data strengthen the existing evidence that, for a person with pancreatic cancer who is proceeding to surgery, the best approach is to avoid pre-operative biliary drainage. The optimal comparison to the neoadjuvant approach is upfront fast-track surgery without biliary drainage followed by adjuvant therapy.

Focal Parenchymal Atrophy of the Pancreas Is Frequently Observed on Pre-Diagnostic Computed Tomography in Patients with Pancreatic Cancer: A Case-Control Study

Pancreatic ductal adenocarcinoma (PDAC) accounts for the majority of all pancreatic cancers and is highly lethal. Focal parenchymal atrophy (FPA) of the pancreas has been reported as a characteristic imaging finding of early PDAC. Here, we reviewed 76 patients with PDAC who underwent computed tomography (CT) between 6 months and 3 years before PDAC diagnosis, as well as 76 sex- and age-matched controls without PDAC on CT examinations separated by at least 5 years. FPA was observed corresponding to the location of the subsequent tumor on pre-diagnostic CT in 14/44 (31.8%) patients between 6 months and 1 year, 14/51 (27.5%) patients between 1 and 2 years, and 9/41 (22.0%) patients between 2 and 3 years before PDAC diagnosis. Overall, FPA was more frequently observed in patients with PDAC (26/76; 34.2%) on pre-diagnostic CT than that in controls (3/76; 3.9%) (p < 0.001). FPA was observed before the appearance of cut-off/dilatation of the main pancreatic duct, suggesting that FPA might be the earliest sign of PDAC. FPA was less frequently found in tumors in the pancreatic head (3/27; 11.1%) than in those in the body (14/30; 46.7%) or tail (9/19; 47.4%). FPA may predict the subsequent PDAC diagnosis, serving as an important imaging sign for the early diagnosis of pancreatic cancer.

Automated procedure assessing the accuracy of HRCT–PET registration applied in functional virtual bronchoscopy

Background Bronchoscopy serves as direct visualisation of the airway. Virtual bronchoscopy provides similar visual information using a non-invasive imaging procedure(s). Early and accurate image-guided diagnosis requires the possible highest performance, which might be approximated by combining anatomical and functional imaging. This communication describes an advanced functional virtual bronchoscopic (fVB) method based on the registration of PET images to high-resolution diagnostic CT images instead of low-dose CT images of lower resolution obtained from PET/CT scans. PET/CT and diagnostic CT data were collected from 22 oncological patients to develop a computer-aided high-precision fVB. Registration of segmented images was performed using elastix. Results For virtual bronchoscopy, we used an in-house developed segmentation method. The quality of low- and high-dose CT image registrations was characterised by expert’s scoring the spatial distance of manually paired corresponding points and by eight voxel intensity-based (dis)similarity parameters. The distribution of (dis)similarity parameter correlating best with anatomic scoring was bootstrapped, and 95% confidence intervals were calculated separately for acceptable and insufficient registrations. We showed that mutual information (MI) of the eight investigated (dis)similarity parameters displayed the closest correlation with the anatomy-based distance metrics used to characterise the quality of image registrations. The 95% confidence intervals of the bootstrapped MI distribution were [0.15, 0.22] and [0.28, 0.37] for insufficient and acceptable registrations, respectively. In case of any new patient, a calculated MI value of registered low- and high-dose CT image pair within the [0.28, 0.37] or the [0.15, 0.22] interval would suggest acceptance or rejection, respectively, serving as an aid for the radiologist. Conclusion A computer-aided solution was proposed in order to reduce reliance on radiologist’s contribution for the approval of acceptable image registrations.

Radiation dosimetry effect evaluation of a carbon fiber couch on novel uRT-linac 506c accelerator

Recently, a diagnostic helical CT is integrated into a linear accelerator, called uRT-linac 506c, whose CT scanning dataset can be directly used to do simulation. This novel structure provides a possibility for online adaptive radiotherapy. For adaptive radiotherapy, the carbon fiber couch is an essential external device for supporting and positioning patients. And the effect on dose attenuation and distribution caused by a couch is inevitable and vital for precise treatment. In this research, the couch equipped with uRT-linac 506c was evaluated on the radiation dosimetry effect. The treatment couch equipped on the uRT-linac 506c accelerator was evaluated, and its effect on the attenuation, surface dose and dose buildup were measured for different phantom positions (offset = 0 cm, offset = + 10 cm and offset = − 10 cm, respectively) and different gantry angles. Since uRT-linac 506c is exclusively capable to provide diagnostic CT scanning data with real relative electron density (RED), this CT scanning data of the couch can be used directly in uRT-TPS to design plans. This scanned couch dataset was designated as the model A. The model B was a dummy structure of a treatment couch inserted with artificially preset RED. The dose calculation accuracy of these two models was compared using PB, CC, and MC on uRT-TPS. With the effect of carbon fiber couch, the surface dose was increased at least 97.94% for 25 × 25 cm2 field and 188.83% for 10 × 10 cm2 field, compared with those without. At different phantom positions (offset = 0, + 10, − 10 cm), the attenuation for 6 MV photon beam at gantry angle 180° were 4.4%, 4.4%, and 4.3%, respectively, and varied with changes of gantry angle. There do exists dose deviation between measurement and TPS calculation with the involvement of treatment couch, among the three algorithms, MC presented the least deviation, and the model A made less and steadier deviation than the model B, showing promising superiority. The attenuation, surface dose, and buildup effects of the carbon fiber couch in this study were measured similarly to most counterparts. The dose deviation calculated based on the couch dataset scanned by the diagnostic helical CT was smaller than those based on a dummy couch. This result suggests that an accelerator equipped with a diagnostic CT, which can help reduce the dose deviation of the carbon fiber couch, is a promising platform for online adaptive radiotherapy.