The Sequential Radiographic Effects of Preoperative Chemotherapy and (Chemo)Radiation on Tumor Anatomy in Patients with Localized Pancreatic Cancer

Survival Outcomes According to NCCN Criteria for Resection Following Neoadjuvant Therapy for Patients with Localized Pancreatic Cancer

BACKGROUND

This study aimed to assess the prognostic value of the National Comprehensive Cancer Network (NCCN) criteria for resection following neoadjuvant therapy for patients with localized pancreatic ductal adenocarcinoma (PDAC).

METHODS

This retrospective single-center study assessed 193 consecutive patients with localized PDAC (104 males and 89 females; mean age, 61.1 ± 9.4 years) who underwent neoadjuvant therapy followed by surgery between January 2010 and March 2021. Combined resectability and carbohydrate antigen (CA) 19-9 evaluation before and after neoadjuvant therapy was used to determine whether patients were eligible for resection according to the NCCN criteria. Post-surgical overall survival (OS), recurrence free survival (RFS), and pathologic results were evaluated and compared between patients considered eligible according to the NCCN criteria and those considered ineligible. Preoperative factors associated with better OS and RFS also were investigated.

RESULTS

Of the 193 patients, 168 (87.0 %) were eligible for resection according to the NCCN criteria. The patients eligible according to the NCCN criteria showed marginally longer OS than those considered ineligible (p = 0.056). After adjustment of variables, meeting the NCCN criteria for resection was an independent predictor of better OS (hazard ratio, 0.57; 95 % confidence interval, 0.34-0.96; p = 0.034). The two groups had similar RFS. Lower T-staging (T2 or less) and less lympho-vascular invasion and peri-neural invasion were noted in the patients who met the NCCN criteria (p ≤ 0.045).

CONCLUSIONS

The patients eligible for resection according to the NCCN criteria showed a trend toward longer OS and better pathologic results than the patients considered ineligible.

Locally Advanced Pancreas Cancer, Is There a Role for Surgery?

Locally advanced pancreatic cancer (LAPC) represents a unique clinical scenario in which the tumor is considered localized but unresectable due to anatomic factors. Despite a consensus against upfront surgery, no standard approach to induction therapy exists for patients with LAPC. Extended systemic therapy has shown promise in establishing tumor response and remains the standard of care. While associated with improved local control, the timing and role of radiation therapy remain in question. Following adequate response to induction chemotherapy, a safe attempt at margin-negative resection can be considered. Special attention should be given to required vascular skeletonization and/or resection with reconstruction.

Currently Debated Topics on Surgical Treatment of Pancreatic Ductal Adenocarcinoma: A Narrative Review on Surgical Treatment of Borderline Resectable, Locally Advanced, and Synchronous or Metachronous Oligometastatic Tumor

BACKGROUND

Previously considered inoperable patients (borderline resectable, locally advanced, synchronous oligometastatic or metachronous pancreatic adenocarcinoma (PDAC)) are starting to become resectable thanks to advances in chemo/radiotherapy and the reduction in operative mortality.

METHODS

This narrative review presents a chosen literature selection, giving a picture of the current state of treatment of these patients.

RESULTS

Neoadjuvant therapy (NAT) is generally recognized as the treatment of choice before surgery. However, despite the increased efficacy, the best pathological response is still limited to 10.9-27.9% of patients. There are still limited data on the selection of possible NAT responders and how to diagnose non-responders early. Multidetector computed tomography has high sensitivity and low specificity in evaluating resectability after NAT, limiting the resection rate of resectable patients. Ca 19-9 and Positron emission tomography are giving promising results. The prediction of early recurrence after a radical resection of synchronous or metachronous metastatic PDAC, thus identifying patients with poor prognosis and saving them from a resection of little benefit, is still ongoing, although some promising data are available.

CONCLUSION

In conclusion, high-level evidence demonstrating the benefit of the surgical treatment of such patients is still lacking and should not be performed outside of high-volume centers with interdisciplinary teams of surgeons and oncologists.

Can Concurrent Chemoradiotherapy Add Meaningful Benefit in Addition to Induction Chemotherapy in the Management of Borderline Resectable and Locally Advanced Pancreatic Cancer?: A Systematic Review

OBJECTIVES

The role of concomitant chemoradiotherapy or radiotherapy (RT) after induction chemotherapy (IC) in borderline resectable and locally advanced pancreatic ductal adenocarcinoma is debatable. This systematic review aimed to explore this.

METHODS

We searched PubMed, MEDLINE, EMBASE, and Cochrane database. Studies were selected reporting outcomes on resection rate, R0 resection, pathological response, radiological response, progression-free survival, overall survival, local control, morbidity, and mortality.

RESULTS

The search resulted in 6635 articles. After 2 rounds of screening, 34 publications were selected. We found 3 randomized controlled studies and 1 prospective cohort study, and the rest were retrospective studies. There is consistent evidence that addition of concomitant chemoradiotherapy or RT after IC improves pathological response and local control. There are conflicting results in terms of other outcomes.

CONCLUSIONS

Concomitant chemoradiotherapy or RT after IC improves local control and pathological response in borderline resectable and locally advanced pancreatic ductal adenocarcinoma. The role of modern RT in improving other outcome requires further research.

Current Treatment of Potentially Resectable Pancreatic Ductal Adenocarcinoma: A Medical Oncologist's Perspective

Pancreatic cancer has traditionally been associated with a dismal prognosis, even in early stages of the disease. In recent years, the introduction of newer generation chemotherapy regimens in the adjuvant setting has improved the survival of patients treated with upfront resection. However, there are multiple theoretical advantages to deliver early systemic therapy in patients with localized pancreatic cancer. So far, the evidence supports the use of neoadjuvant therapy for patients with borderline resectable pancreatic cancer. The benefit of this treatment sequence for patients with resectable disease remains elusive. In this review, we summarize the data on adjuvant therapy for pancreatic cancer and describe which evidence backs the use of neoadjuvant therapy. Additionally, we address important issues faced in clinical practice when treating patients with localized pancreatic cancer.

Radiation therapy in borderline resectable pancreatic cancer: A review

BACKGROUND

Borderline resectable pancreatic cancer constitutes a complex clinical entity, presenting the clinician with a locally aggressive disease that has a proclivity for distant spread. The benefits of radiation therapy, such as improved local control and improved survival, have been questioned. In this review we seek to summarize the existing evidence on radiation therapy in borderline resectable pancreatic cancer and highlight future areas of research.

METHODS

A comprehensive review of PubMed for clinical studies reporting outcomes in borderline resectable pancreatic cancer was performed in June 2021, with an emphasis placed on prospective studies.

RESULTS

Radiologic "downstaging" in borderline resectable pancreatic cancer is a rare event, although some evidence shows increased clinical response to neoadjuvant chemotherapy over radiation therapy. Margin status seems to be equivalent between regimens that use neoadjuvant chemotherapy alone and regimens that include neoadjuvant radiation therapy. Local control in borderline resectable pancreatic cancer is likely improved with radiation therapy; however, the benefit of improved local control in a disease marked by systemic failure has been questioned. Although some studies have shown improved survival with radiation therapy, differences in the delivery and tolerance of chemotherapy between the neoadjuvant and adjuvant setting confound these results. When the evidence is evaluated as a whole, there is no clear survival benefit of radiation therapy in borderline resectable pancreatic cancer.

CONCLUSION

Once considered a staple of therapy, the role of radiation therapy in borderline resectable pancreatic cancer is evolving as systemic therapy regimens continues to improve. Increased clinical understanding of disease phenotype and response are needed to accurately tailor therapy for individual patients and to improve outcomes in this complex patient population.

Prediction of Margin-Negative Resection of Pancreatic Ductal Adenocarcinoma Following Neoadjuvant Therapy: Diagnostic Performance of NCCN Criteria for Resection vs. CT-Determined Resectability

BACKGROUND

Accurate assessment of pancreatic ductal adenocarcinoma (PDAC) resectability after neoadjuvant therapy (NAT) is crucial. Recently, the NCCN introduced criteria for resection of PDAC following NAT.

METHODS

We analyzed 127 patients who underwent NAT and pancreatectomy for PDAC between January 2010 and March 2020. CT-determined resectability according to the NCCN guideline, and CA 19-9 level was evaluated before and after NAT. Diagnostic performance of the NCCN criteria for margin-negative (R0) resection was investigated and compared with CT alone.

RESULTS

R0 resection was achieved in 104 (81.9%) patients. After NAT, there were 30 (23.6%) resectable, 90 (70.9%) borderline resectable, and seven (5.5%) locally advanced tumors. Significantly decreased or stable CA 19-9 levels were noted in 114 (89.8%) patients. The sensitivity and specificity of the NCCN criteria were 87.5% (91/104) and 21.7% (5/23), respectively, which were significantly different from CT including only resectable PDAC (26.9% [28/104] and 91.3% [21/23]; p<0.001), but less prominently different from CT including resectable and borderline resectable PDAC (95.2% [99/104]; p=0.022 and 8.7% [2/23]; p=0.375).

CONCLUSIONS

The NCCN criteria for resection following NAT showed high sensitivity and low specificity for predicting R0 resection. It had supplementary benefit over CT alone, mainly in preventing underestimation of R0 resection.

Organoids Derived from Neoadjuvant FOLFIRINOX Patients Recapitulate Therapy Resistance in Pancreatic Ductal Adenocarcinoma

PURPOSE

We investigated whether organoids can be generated from resected tumors of patients who received eight cycles of neoadjuvant FOLFIRINOX chemotherapy before surgery, and evaluated the sensitivity/resistance of these surviving cancer cells to cancer therapy.

EXPERIMENTAL DESIGN

We generated a library of 10 pancreatic ductal adenocarcinoma (PDAC) organoid lines: five each from treatment-naïve and FOLFIRINOX-treated patients. We first assessed the histologic, genetic, and transcriptional characteristics of the organoids and their matched primary PDAC tissue. Next, the organoids' response to treatment with single agents-5-FU, irinotecan, and oxaliplatin-of the FOLFIRINOX regimen as well as combined regimen was evaluated. Finally, global mRNA-seq analyses were performed to identify FOLFIRINOX resistance pathways.

RESULTS

All 10 patient-derived PDAC organoids recapitulate histologic, genetic, and transcriptional characteristics of their primary tumor tissue. Neoadjuvant FOLFIRINOX-treated organoids display resistance to FOLFIRINOX (5/5), irinotecan (5/5), and oxaliplatin (4/5) when compared with treatment-naïve organoids (FOLFIRINOX: 1/5, irinotecan: 2/5, oxaliplatin: 0/5). 5-Fluorouracil treatment responses between naïve and treated organoids were similar. Comparative global transcriptome analysis of treatment-naïve and FOLFIRINOX samples-in both organoids and corresponding matched tumor tissues-uncovered modulated pathways mainly involved in genomic instability, energy metabolism, and innate immune system.

CONCLUSIONS

Resistance development in neoadjuvant FOLFIRINOX organoids, recapitulating their primary tumor resistance, suggests continuation of FOLFIRINOX therapy as an adjuvant treatment may not be advantageous for these patients. Gene-expression profiles of PDAC organoids identify targetable pathways involved in chemoresistance development upon neoadjuvant FOLFIRINOX treatment, thus opening up combination therapy possibilities.

Development and Validation of Multicenter Predictive Nomograms for Locally Advanced Pancreatic Cancer After Chemoradiotherapy

OBJECTIVE

Due to common practice of hypofractionated radiotherapy in pancreatic cancer and heterogeneous chemotherapy regimens in previous studies, modified nomograms are required. Therefore, we aim to develop and validate prognostic nomograms for locally advanced pancreatic cancer (LAPC) after stereotactic body radiation therapy (SBRT) and chemotherapy.

METHODS

The development cohort comprised 925 patients with LAPC receiving SBRT and gemcitabine-based chemotherapy in our center, while 297 patients from another two centers formed the validation cohort. Nomograms were created from COX models and internally validated by bootstrap. Model discriminations were evaluated by calibration plots and concordance index (C-index). A decision curve analysis (DCA) was performed to evaluate clinical benefits of nomograms. Additionally, recursive partitioning analysis (RPA) was used for stratifications of survival probability based on the total score of each patient calculated by nomograms.

RESULTS

Weight loss, tumor diameter, radiation dose, CA19-9 kinetics after treatment and surgical resection were included in the nomogram for overall survival (OS), while the five factors plus performance status formed the nomogram for progression free survival (PFS). The corrected C-indexes for estimated 1-year and 2-year OS of the development cohort were 0.88 (95% CI: 0.85-0.91) and 0.86 (95% CI: 0.83-0.90). For those of the validation cohort, it was 0.88 (95% CI: 0.82-0.94) and 0.83 (95% CI: 0.74-0.91). Additionally, the corrected C-index for predicted 1-year PFS in the development and validation cohort was 0.83 (95% CI: 0.81-0.86) and 0.82 (95% CI: 0.78-0.87), respectively. The calibration plots showed good agreement of 1- and 2-year OS and 1-year PFS between the estimations and actual observations. Potential clinical benefits were demonstrated with DCA. Additionally, for 1- and 2-year OS and 1-year PFS, patients were stratified into four groups with different survival probability by RPA.

CONCLUSION

The validated nomograms provided useful predictions of OS and PFS for LAPC with chemoradiotherapy.

A review of response in neoadjuvant therapy for exocrine pancreatic cancer

Despite overall advances in cancer therapy, patients with pancreatic ductal adenocarcinoma continue to have a poor prognosis. While adjuvant therapy is still considered standard, there is mounting evidence that neoadjuvant therapy confers similar benefits in patients with locally advanced disease. The primary measures of response are radiographic, biochemical, margin status, and pathologic. Given overall low response rates and the need for new treatment strategies, standard metrics remain important to the investigation of new systemic agents.

Radiotherapy for Resectable and Borderline Resectable Pancreas Cancer: When and Why?

The role of (chemo) radiation in the perioperative management of patients with resectable and borderline resectable pancreatic ductal adenocarcinoma is controversial. Herein, we review and interpret existing data relating to the ability of (chemo) radiation to "downstage" pancreatic tumors, delay recurrence, and prolong patients' survival. In sum, the evidence suggests that while neoadjuvant (chemo) radiation may impact pathologic metrics favorably, it rarely converts anatomically unresectable tumors to resectable ones. And while data do support the ability of (chemo)radiation to delay cancer progression, its ability to prolong longevity has not been confirmed. It is possible that (chemo)radiation is effective in prolonging the survival of select patients, but to date, this cohort remains undefined due to heterogeneity in both the populations studied and the regimens used to treat them. Based on our interpretation of existing data, we currently administer neoadjuvant and adjuvant (chemo)radiation selectively to patients with localized pancreatic cancer who we consider at highest risk for local progression. We may also use it as an alternative to pancreatectomy in patients who are poor candidates for surgery. Ultimately, the role of (chemo)radiation in these settings is evolving. Better studies of patients most likely to benefit from its local effects are necessary to clearly define its place within the perioperative treatment algorithms used for patients with localized pancreatic cancer.

Defining and Treating Borderline Resectable Pancreatic Cancer

OPINION STATEMENT

Patients with borderline resectable pancreatic ductal adenocarcinoma (BR PDAC) should receive preoperative chemotherapy with or without radiation therapy, with the intent to eradicate occult metastatic cancer cells, to select patients with a "locally dominant cancer phenotype" for whom local therapies might be most effective, and to reduce the anatomic extent of tumors to facilitate surgical resection. The administration of preoperative therapy may also be a useful strategy to deliver the maximum load of chemotherapy to patients with BR PDAC, since as many as half of patients will never qualify for adjuvant treatments following pancreatectomy due to postoperative morbidity or disease progression. Patients with BR PDAC should be categorized at diagnosis on the basis of anatomical, biological, and conditional criteria and should be offered induction systemic chemotherapy with close monitoring for toxicity, followed by administration of (chemo)radiation in selected cases. Patients should be restaged after systemic therapy and, if used, (chemo)radiation. Patients who continue to show disease response or disease stability without signs of progression should be considered for pancreatectomy; better measures of response to therapy are needed.