Time to Progression of Pancreatic Cancer: Evaluation with Multi-Detector Computed Tomography

Identification of a serum proteomic biomarker panel using diagnosis specific ensemble learning and symptoms for early pancreatic cancer detection

BACKGROUND

The grim (<10% 5-year) survival rates for pancreatic ductal adenocarcinoma (PDAC) are attributed to its complex intrinsic biology and most often late-stage detection. The overlap of symptoms with benign gastrointestinal conditions in early stage further complicates timely detection. The suboptimal diagnostic performance of carbohydrate antigen (CA) 19-9 and elevation in benign hyperbilirubinaemia undermine its reliability, leaving a notable absence of accurate diagnostic biomarkers. Using a selected patient cohort with benign pancreatic and biliary tract conditions we aimed to develop a data analysis protocol leading to a biomarker signature capable of distinguishing patients with non-specific yet concerning clinical presentations, from those with PDAC.

METHODS

539 patient serum samples collected under the Accelerated Diagnosis of neuro Endocrine and Pancreatic TumourS (ADEPTS) study (benign disease controls and PDACs) and the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS, healthy controls) were screened using the Olink Oncology II panel, supplemented with five in-house markers. 16 specialized base-learner classifiers were stacked to select and enhance biomarker performances and robustness in blinded samples. Each base-learner was constructed through cross-validation and recursive feature elimination in a discovery set comprising approximately two thirds of the ADEPTS and UKCTOCS samples and contrasted specific diagnosis with PDAC.

RESULTS

The signature which was developed using diagnosis-specific ensemble learning demonstrated predictive capabilities outperforming CA19-9, the only biomarker currently accepted by the FDA and the National Comprehensive Cancer Network guidelines for pancreatic cancer, and other individual biomarkers and combinations in both discovery and held-out validation sets. An AUC of 0.98 (95% CI 0.98-0.99) and sensitivity of 0.99 (95% CI 0.98-1) at 90% specificity was achieved with the ensemble method, which was significantly larger than the AUC of 0.79 (95% CI 0.66-0.91) and sensitivity 0.67 (95% CI 0.50-0.83), also at 90% specificity, for CA19-9, in the discovery set (p = 0.0016 and p = 0.00050, respectively). During ensemble signature validation in the held-out set, an AUC of 0.95 (95% CI 0.91-0.99), sensitivity 0.86 (95% CI 0.68-1), was attained compared to an AUC of 0.80 (95% CI 0.66-0.93), sensitivity 0.65 (95% CI 0.48-0.56) at 90% specificity for CA19-9 alone (p = 0.0082 and p = 0.024, respectively). When validated only on the benign disease controls and PDACs collected from ADEPTS, the diagnostic-specific signature achieved an AUC of 0.96 (95% CI 0.92-0.99), sensitivity 0.82 (95% CI 0.64-0.95) at 90% specificity, which was still significantly higher than the performance for CA19-9 taken as a single predictor, AUC of 0.79 (95% CI 0.64-0.93) and sensitivity of 0.18 (95% CI 0.03-0.69) (p = 0.013 and p = 0.0055, respectively).

CONCLUSION

Our ensemble modelling technique outperformed CA19-9, individual biomarkers and indices developed with prevailing algorithms in distinguishing patients with non-specific but concerning symptoms from those with PDAC, with implications for improving its early detection in individuals at risk.

Earlier Diagnosis of Pancreatic Cancer: Is It Possible?

Pancreatic ductal adenocarcinoma has a very high mortality rate which has been only minimally improved in the last 30 years. This high mortality is closely related to late diagnosis, which is usually made when the tumor is large and has extensively infiltrated neighboring tissues or distant metastases are already present. This is a paradoxical situation for a tumor that requires nearly 15 years to develop since the first founding mutation. Response to chemotherapy under such late circumstances is poor, resistance is frequent, and prolongation of survival is almost negligible. Early surgery has been, and still is, the only approach with a slightly better outcome. Unfortunately, the relapse percentage after surgery is still very high. In fact, early surgery clearly requires early diagnosis. Despite all the advances in diagnostic methods, the available tools for improving these results are scarce. Serum tumor markers permit a late diagnosis, but their contribution to an improved therapeutic result is very limited. On the other hand, effective screening methods for high-risk populations have not been fully developed as yet. This paper discusses the difficulties of early diagnosis, evaluates whether the available diagnostic tools are adequate, and proposes some simple and not-so-simple measures to improve it.

Pancreatic cancer detection with a non-contrast MR protocol: is it reliable?

PURPOSE

The pancreatic cancer (PC) is the 4th leading cancer-related death, becoming the second one by 2030, with a 5 year survival rate of 8%. Considering its increased incidence in high-risk categories compared to the general population, we aimed to validate a non-contrast MR protocol, to detect PC in its earliest phase, which could be suitable as a screening tool in high-risk patients.

MATERIALS AND METHODS

In this retrospective study, we selected 200 patients (> 40 years) from our radiological database, which performed upper abdominal MRI between 2012 and 2017. 100 were negative for pancreatic lesions and 100 positive for pancreatic lesion (< 30 mm). The latter group included: 40 PDAC (pancreatic adenocarcinoma), 42 BD-IPMN (Branch Duct- Intraductal Papillary Mucinous Neoplasm), 10 PNET(pancreatic neuroendocrine tumor), 4 SCN(serous cystic neoplasm), 3 IPS(intrapancreatic spleen), 1 MCN(mucinous cystic neoplasm). Three readers (R1, R2 and R3) with a high, medium and low experience, respectively, analysed, first, the non-contrast MR sequences (single-shot T2w breath-hold, GE T1w FS, DWI and 2D/3D MRCP), and then the standard MR protocol, independently, randomly and anonymously. Readers identified or excluded the presence of pancreatic lesion, in both reading sessions. These results were compared with the histopathological diagnosis, and then divided into 3 different classes of lesions: all lesions, pancreatic adenocarcinoma and solid lesion. Mcnemar's test was used to compare the results. The inter-observer agreement was determined according to the kappa statistic in both protocols, and then the inter-protocol agreement was calculated.

RESULTS

The non-contrast MR protocol has reached statistical parameters values ranging between 83% in SE (sensitivity) by R3 and 99% in NPV (negative predictive value) by R1. The standard MR protocol has reported slight increasing statistical parameters compared to those of the proposed one. However, there are not significant statistical differences between the both protocols. The proposed non-contrast MR protocol has reported the highest NPVs in the PDAC group detection (R1: 99%, R2: 99%, R3: 98%). In all groups of lesions, the agreement between the two protocols was excellent for each Reader ranging from 96 to 98%.

CONCLUSION

The proposed non-contrast MR protocol showed high PC detection values and a time execution ≤ 20 min. Therefore, it can be proposed as a screening tool in high-risk patients.

Maintaining early diagnosis of pancreatic adenocarcinoma in Japan: Local resilience against COVID-19

BACKGROUND AND AIMS

This study evaluated the impact of the coronavirus disease 2019 (COVID-19) pandemic on pancreatic adenocarcinoma (PA) practice in our region and discussed the effects of our institution's regional collaborative system, the "Early Stage Pancreatic Cancer Diagnosis Project," which was originally unrelated to this study's purpose.

METHODS

We retrospectively investigated 150 patients with PA at Yokohama Rosai Hospital by defining three time periods: before (C0), during the first year (C1), and during the second year (C2) of the COVID-19 pandemic.

RESULTS

Among the three periods (C0, C1, and C2), there were significantly less patients with stage I PA (14.0%, 0%, and 7.4%, p = 0.032) in C1, and significantly more patients with stage III PA (10.0%, 28.3%, and 9.3%, p = 0.014) in C1. The pandemic significantly prolonged the median durations from disease onset to patients' first visits (28, 49, and 14 days, p = 0.012). In contrast, there was no significant difference in the median durations from referral to first visit to our institution (4, 4, and 6 days, p = 0.391).

CONCLUSIONS

The pandemic advanced the stage of PA in our region. Although the pancreatic referral network remained functional during the pandemic, there were delays from disease onset to patients' first visit to healthcare providers, including clinics. While the pandemic caused temporary damage to PA practice, the routine regional collaboration provided by our institution's project allowed for early resilience. A notable limitation is that the impact of the pandemic on PA prognosis was not evaluated.

Outcomes of patients undergoing elective liver and pancreas cancer surgery during the SARS-CoV-2 pandemic: an international, multicentre, prospective cohort study

BACKGROUND

The effect of SARS-CoV-2 infection upon HPB cancer surgery perioperative outcomes is unclear. Establishing risk is key to individualising treatment pathways. We aimed to identify the mortality rate and complications risk for HPB cancer elective surgery during the pandemic.

METHODS

International, prospective, multicentre study of consecutive adult patients undergoing elective HPB cancer operations during the initial SARS-CoV-2 pandemic. Primary outcome was 30-day perioperative mortality. Secondary outcomes included major and surgery-specific 30-day complications. Multilevel cox proportional hazards and logistic regression models estimated association of SARS-CoV-2 and postoperative outcomes.

RESULTS

Among 2038 patients (259 hospitals, 49 countries; liver n = 1080; pancreas n = 958) some 6.2%, n = 127, contracted perioperative SARS-CoV-2. Perioperative mortality (9.4%, 12/127 vs 2.6%, 49/1911) and major complications (29.1%, 37/127 vs 13.2%, 253/1911) were higher with SARS-CoV-2 infection, persisting when age, sex and comorbidity were accounted for (HR survival 4.15, 95% CI 1.64 to 10.49; OR major complications 3.41, 95% CI 1.72 to 6.75). SARS-CoV-2 was associated with late postoperative bleeding (11.0% vs 4.2%) and grade B/C postoperative pancreatic fistula (17.9% vs 8.6%).

CONCLUSION

SARS-CoV-2 infection was associated with significantly higher perioperative morbidity and mortality. Patients without SARS-CoV-2 had acceptable morbidity and mortality rates, highlighting the need to protect patients to enable safe ongoing surgery.

Identification of distinct slow mode of reversible adaptation of pancreatic ductal adenocarcinoma to the prolonged acidic pH microenvironment

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is the most common pancreatic neoplasm with high metastatic potential and poor clinical outcome. Like other solid tumors, PDAC in the early stages is often asymptomatic, and grows very slowly under a distinct acidic pHe (extracellular pH) microenvironment. However, most previous studies have only reported the fate of cancerous cells upon cursory exposure to acidic pHe conditions. Little is known about how solid tumors-such as the lethal PDAC originating within the pancreatic duct-acinar system that secretes alkaline fluids-evolve to withstand and adapt to the prolonged acidotic microenvironmental stress.

METHODS

Representative PDAC cells were exposed to various biologically relevant periods of extracellular acidity. The time effects of acidic pHe stress were determined with respect to tumor cell proliferation, phenotypic regulation, autophagic control, metabolic plasticity, mitochondrial network dynamics, and metastatic potentials.

RESULTS

Unlike previous short-term analyses, we found that the acidosis-mediated autophagy occurred mainly as an early stress response but not for later adaptation to microenvironmental acidification. Rather, PDAC cells use a distinct and lengthy process of reversible adaptive plasticity centered on the early fast and later slow mitochondrial network dynamics and metabolic adjustment. This regulates their acute responses and chronic adaptations to the acidic pHe microenvironment. A more malignant state with increased migratory and invasive potentials in long-term acidosis-adapted PDAC cells was obtained with key regulatory molecules being closely related to overall patient survival. Finally, the identification of 34 acidic pHe-related genes could be potential targets for the development of diagnosis and treatment against PDAC.

CONCLUSIONS

Our study offers a novel mechanism of early rapid response and late reversible adaptation of PDAC cells to the stress of extracellular acidosis. The presence of this distinctive yet slow mode of machinery fills an important knowledge gap in how solid tumor cells sense, respond, reprogram, and ultimately adapt to the persistent microenvironmental acidification.

Analysis of Progression Time in Pancreatic Cancer including Carcinoma In Situ Based on Magnetic Resonance Cholangiopancreatography Findings

BACKGROUND

Pancreatic cancer (PC) exhibits extremely rapid growth; however, it remains largely unknown whether the early stages of PC also exhibit rapid growth speed equivalent to advanced PC. This study aimed to investigate the natural history of early PCs through retrospectively assessing pre-diagnostic images.

METHODS

We examined the data of nine patients, including three patients with carcinoma in situ (CIS), who had undergone magnetic resonance cholangiopancreatography (MRCP) to detect solitary main pancreatic duct (MPD) stenosis >1 year before definitive PC diagnosis. We retrospectively analyzed the time to diagnosis and first-time tumor detection from the estimated time point of first-time MPD stenosis detection without tumor lesion.

RESULTS

The median tumor size at diagnosis and the first-time tumor detection size were 14 and 7.5 mm, respectively. The median time to diagnosis and first-time tumor detection were 26 and 49 months, respectively.

CONCLUSIONS

No studies have investigated the PC history, especially that of early PCs, including CIS, based on the initial detection of MPD stenosis using MRCP. Assessment of a small number of patients showed that the time to progression can take several years in the early PC stages. Understanding this natural history is very important in the clinical setting.

Retrospective evaluation of venous phase contrast-enhanced computed tomography images in patients who developed pancreatic adenocarcinomas after treatment for nonpancreatic primary cancer

Objectives:

To clarify venous phase contrast-enhanced CT findings in early pancreatic adenocarcinomas by retrospectively evaluating CT images of pancreatic adenocarcinomas that developed during follow-up after treatment for non-pancreatic cancers.

Methods:

The study cohort comprised six patients who developed pancreatic adenocarcinomas between April 2005 and April 2020 during follow-up after treatment for non-pancreatic primary cancers. Two radiologists retrospectively evaluated CT images and reached consensus on previously reported CT findings that were suggestive of small pancreatic adenocarcinomas; namely pancreatic duct interruption and dilatation, pancreatic parenchymal atrophy, focal hypoattenuated areas, and appearance of cystic lesions. Time intervals between the first CT with these suggestive findings and the latest pre-operative CT were recorded. Doubling times were calculated in patients with hypoattenuated areas on initial CT scans.

Results:

Small (<10 mm) focal hypoattenuated areas with (n = 2) or without rim enhancement (n = 1) were identified on initial CT images of three patients. Pancreatic duct interruption and dilatation, pancreatic parenchymal atrophy, and cystic lesion were identified in two, one and one patient, respectively. Time intervals between initial and latest preoperative CT examination were 6–19 months (median, 14.5 months). Tumor doubling time according to CT findings was calculated as 46–407 days (median 106 days).

Conclusion:

Venous phase contrast-enhanced CT can provide findings that are suggestive of early pancreatic adenocarcinoma. Pancreatic phase contrast-enhanced CT should therefore be performed in patients with such findings with the aim of early detection of pancreatic adenocarcinoma.

Advances in knowledge:

Pancreatic adenocarcinoma can develop subsequently in patients with non-pancreatic malignancies. Patients with non-pancreatic cancers are often followed up with monophasic contrast-enhanced CT in venous phase timing. Venous phase contrast-enhanced CT can provide some findings suggestive of early pancreatic adenocarcinoma. Knowledge of these findings is important for early detection of pancreatic adenocarcinoma.

Acute Pancreatitis as the Initial Presentation of Pancreatic Adenocarcinoma does not Impact Short- and Long-term Outcomes of Curative Intent Surgery: A Study of the French Surgical Association

BACKGROUND

Acute pancreatitis (AP) can be one of the earliest clinical presentation of pancreatic ductal adenocarcinoma (PDAC). Information about the impact of AP on postoperative outcomes as well as its influences on PDAC survival is scarce. This study aimed to determine whether AP as initial clinical presentation of PDAC impact the short- and long-term outcomes of curative intent pancreatic resection.

PATIENTS AND METHODS

From 2004 to 2009, 1449 patients with PDAC underwent pancreatic resection in 37 institutions (France, Belgium and Switzerland). We used univariate and multivariate analysis to identify factors associated with severe complications and pancreatic fistula as well as overall and disease-free survivals.

RESULTS

There were 764 males (52,7%), and the median age was 64 years. A total of 781 patients (53.9%) developed at least one complication, among whom 317 (21.8%) were classified as Clavien-Dindo ≥ 3. A total of 114 (8.5%) patients had AP as the initial clinical manifestation of PDAC. This situation was not associated with any increase in the rates of postoperative fistula (21.2% vs 16.4%, P = 0.19), postoperative complications (57% vs 54.2%, P = 0.56), and 30 day mortality (2.6% vs 3.4%, P = 1). In multivariate analysis, AP did not correlate with postoperative complications or pancreatic fistula. The median length of follow-up was 22.4 months. The median overall survival after surgery was 29.9 months in the AP group and 30.5 months in the control group. Overall recurrence rate and local recurrence rate did not differ between groups.

CONCLUSION

AP before PDAC resection did not impact postoperative morbidity and mortality, as well as recurrence rate and survival.

Factors associated with missed and misinterpreted cases of pancreatic ductal adenocarcinoma

OBJECTIVES

To retrospectively examine US, CT, and MR imaging examinations of missed or misinterpreted pancreatic ductal adenocarcinoma (PDAC), and identify factors which may have confounded detection or interpretation.

METHODS

We reviewed 107 examinations in 66/257 patients (26%, mean age 73.7 years) diagnosed with PDAC in 2014 and 2015, with missed or misinterpreted imaging findings as determined by a prior study. For each patient, images and reports were independently reviewed by two radiologists, and in consensus, the following factors which may have confounded assessment were recorded: inherent tumor factors, concurrent pancreatic pathology, technical limitations, and cognitive biases. Secondary signs of PDAC associated with each examination were recorded and compared with the original report to determine which findings were missed.

RESULTS

There were 66/107 (62%) and 49/107 (46%) cases with missed and misinterpreted imaging findings, respectively. A significant number of missed tumors were < 2 cm (45/107, 42%), isoattenuating on CT (32/72, 44%) or non-contour deforming (44/107, 41%). Most (29/49, 59%) misinterpreted examinations were reported as uncomplicated pancreatitis. Almost all examinations (94/107, 88%) demonstrated secondary signs; pancreatic duct dilation was the most common (65/107, 61%) and vascular invasion was the most commonly missed 35/39 (90%). Of the CT and MRIs, 28 of 88 (32%) had suboptimal contrast dosing. Inattentional blindness was the most common cognitive bias, identified in 55/107 (51%) of the exams.

CONCLUSION

Recognizing pitfalls of PDAC detection and interpretation, including intrinsic tumor features, secondary signs, technical factors, and cognitive biases, can assist radiologists in making an early and accurate diagnosis.

KEY POINTS

• There were 66/107 (62%) and 49/107 (46%) cases with missed and misinterpreted imaging findings, respectively, with tumoral, technical, and cognitive factors leading to the misdiagnosis of pancreatic ductal adenocarcinoma. • The majority (29/49, 59%) of misinterpreted cases of pancreatic ductal adenocarcinoma were mistaken for pancreatitis, where an underlying mass or secondary signs were not appreciated due to inflammatory changes. • The most common missed secondary sign of pancreatic ductal adenocarcinoma was vascular encasement, missed in 35/39 (90%) of cases, indicating the importance of evaluating the peri-pancreatic vasculature.

Considerations for the treatment of pancreatic cancer during the COVID-19 pandemic: the UK consensus position

The coronavirus disease 2019 (COVID-19) pandemic epicentre has moved to the USA and Europe, where it is placing unprecedented demands on healthcare resources and staff availability. These service constraints, coupled with concerns relating to an increased incidence and severity of COVID-19 among patients with cancer, should lead to re-consideration of the risk-benefit balance for standard treatment pathways. This is of particular importance to pancreatic cancer, given that standard diagnostic modalities such as endoscopy may be restricted, and that disease biology precludes significant delays in treatment. In light of this, we sought consensus from UK clinicians with an interest in pancreatic cancer for management approaches that would minimise patient risk and accommodate for healthcare service restrictions. The outcomes are described here and include recommendations for treatment prioritisation, strategies to bridge to later surgical resection in resectable disease and factors that modify the risk-benefit balance for treatment in the resectable through to the metastatic settings. Priority is given to strategies that limit hospital visits, including through the use of hypofractionated precision radiotherapy and chemoradiotherapy treatment approaches.

Benefits Of Timely Care In Pancreatic Cancer: A Systematic Review To Navigate Through The Contradictory Evidence

The evidence base of policies that improve the timeliness of cancer care is under ongoing debate. Pancreatic cancer is frequently diagnosed in a stage when curative therapy is not feasible; hence, it is an important target for timelier healthcare interventions. The objectives of our research were to identify all clinical studies on pancreatic cancer care delays via a systematic literature review, to assess the study methodologies for possible biases, to conclude on the available evidence, and to formulate research recommendations on evidence gaps. Nineteen studies were identified and eight reported multivariate analyses. Although many sources of bias shifted the results towards negative or paradoxical findings, a statistically significant association of shorter delays with better clinical outcomes was demonstrated in the majority of studies reporting multivariate analyses. Noninferiority analyses were not published. Further efforts to provide timely care for pancreatic cancer patients are encouraged, and studies on the associations of delay with patient experience and healthcare resource utilization are warranted.

Natural History of Pancreatic Ductal Adenocarcinoma Diagnosed During Observation of Other Organ Cancers

BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) is a rapidly progressive malignancy that exhibits an extremely poor prognosis, with most cases diagnosed at an advanced stage. To date, few reports have explored the natural history of PDAC, and the period leading up to the detection of PDAC as a tumor with contrast-enhanced computed tomography (CECT) remains unclear. Here, we report 3 PDAC cases diagnosed incidentally by repeating imaging examinations during observation of other organ cancers. CASE REPORT Two patients were undergoing postoperative follow-up for colorectal cancer; owing to the elevation of serum CA19-9 or dilatation of the main pancreatic duct, both cases were finally diagnosed with PDAC. Another patient was administered neoadjuvant chemotherapy for a gastrointestinal stromal tumor; the fluorodeoxyglucose uptake in the pancreas with fluorodeoxyglucose positron emission tomography for the treatment assessment led to the diagnosis of PDAC. All patients underwent frequent CECT for assessment of other diseases, and PDAC became visible with CECT within 3-4 months of the appearance of indirect findings of PDAC. CONCLUSIONS The period leading up to the detection of PDAC as a tumor with CECT was approximately 3-4 months. These cases suggest that additional imaging examinations should be performed when the indirect findings of PDAC are noted. This report adds value to the literature by elucidating the natural course of PDAC.

Why is pancreatic cancer so deadly? The pathologist's view

The remarkable aggressiveness of pancreatic cancer has never been fully explained. Although clearly multifactorial, we postulate that venous invasion, a finding seen in most pancreatic cancers but not in most cancers of other organs, may be a significant, underappreciated contributor to the aggressiveness of this disease. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Pancreatic Duct Stricture That Rapidly Progressed to Pancreatic Ductal Adenocarcinoma and Formed a Mass within 3 Months: A Case Report

The natural growth rate of pancreatic carcinoma in situ with pancreatic duct stricture remains unclear. Herein, we present a case with pancreatic duct stricture that rapidly grew to form a mass lesion within 3 months. A 74-year-old woman was referred to us for the investigation of a pancreatic duct dilatation. Initial images did not reveal any clear mass lesions near the pancreatic duct stricture. Pancreatic juice cytology showed suspicious findings. Distal pancreatectomy was recommended; however, the patient refused to undergo surgical treatment at that time. Images taken 3 months later demonstrated a nodular pancreatic body mass which was identified as a moderately to poorly differentiated tubular adenocarcinoma. Previous reports have suggested that pancreatic carcinoma in situ and small pancreatic ductal adenocarcinoma require at least 1–2 years to progress to an advanced mass. This case suggests that pancreatic carcinoma in situ may grow rapidly and indicates a need for close follow-up in patients with pancreatic duct strictures, even if the pathological evidence is not confirmed.

Preoperative CT in patients with surgically resectable pancreatic adenocarcinoma: does the time interval between CT and surgery affect survival?

PURPOSE

The preoperative imaging-to-surgery time interval (ISI) influences the risk of unexpected progression (UP) found at surgery for pancreatic adenocarcinoma. We aimed to assess whether ISI influences disease recurrence and/or survival.

METHODS AND MATERIALS

A single-institution, ethics board-approved retrospective analysis of all patients who underwent attempted resection of pancreatic (PDAC) or periampullary adenocarcinoma (AmpAC) between 1st January 2010 and 31st December 2015 was performed. All patients underwent preoperative abdominal computed tomography (CT). Exclusion criteria were borderline resectable disease and neoadjuvant chemo/radiotherapy. Patients were followed up until 30th June 2016. The population was divided into ISI ≥/<25 days. Kaplan-Meier and Cox regression survival analyses were performed.

RESULTS

239 patients underwent surgical exploration. UP was found in 29 (12.1%) and these patients had longer ISI (median 46 vs. 29 days, p < 0.05). When intention-to-treat analysis was performed, there was no difference in overall survival (OS) between patients with ISI ≥/<25. In those who underwent resection, ISI did not influence disease-free survival (DFS) or OS for PDAC (n = 174). For AmpAC (n = 36), ISI ≥ 25 days was associated with longer OS (p < 0.05) but did not influence DFS. Longer ISI was independently associated with improved OS on regression analysis for AmpAC.

CONCLUSION

Performing surgery for resectable pancreatic adenocarcinoma within 25 days of abdominal CT reduces the chance of UP but does not confer a survival benefit. For those who undergo resection of AmpAC, a longer ISI was associated with longer OS. This probably represents a more biologically indolent disease in this cohort.