Clinical Effects of Stereotactic Body Radiation Therapy Targeting the Primary Tumor of Liver-Only Oligometastatic Pancreatic Cancer

Differentiation Stage Predicts Radiosensitivity in Mesenchymal-Like Pancreatic Cancer

PURPOSE

To derive a genomic classifier to predict radiosensitivity of pancreatic cancer cell lines and patients with pancreatic cancer to allow genomic-guided radiation therapy.

METHODS AND MATERIALS

We collected a comprehensive data set of full clonogenic cell survival curves of 45 pancreatic cancer cell lines irradiated with clinical photon and proton beams. We derived classifiers based on data from human embryonic and fetal pancreas single-cell RNA-sequencing to distinguish between epithelial and mesenchymal cells and to predict pancreas cell-line differentiation stage. Independent testing was done with an embryonic mouse pancreas single-cell RNA-sequencing data set. We then used bulk RNA-seq profiles from the Cancer Cell Line Encyclopedia to classify our pancreatic cancer cell lines using our epithelial-mesenchymal and differentiation stage classifiers. We then correlated the differentiation stage classifier with the radiosensitivity of the pancreatic cancer cell lines as well as with pancreatic cancer patient data from The Cancer Genome Atlas.

RESULTS

We found wide variability in radiosensitivity to both photons and protons among pancreatic cancer cell lines. We showed that the differentiation stage is predictive of radiosensitivity of mesenchymal pancreatic cancer cell lines but not epithelial pancreatic cancer cell lines. We found that chromatin compaction is associated with the differentiation stage and showed that the less differentiated mesenchymal pancreatic cancer cell lines tend to be radioresistant and with more compact chromatin than the radiosensitive differentiated cell lines. Patients with more differentiated tumors exhibit better overall survival.

CONCLUSIONS

We found that mesenchymal-like undifferentiated pancreatic cancer cell lines are more radioresistant than mesenchymal-like differentiated ones and that patients with pancreatic cancer with mesenchymal-like undifferentiated tumors treated with radiation therapy tend to have lower overall survival compared with patients with mesenchymal-like differentiated tumors. We show that it is feasibility to use the differentiation stage of mesenchymal pancreatic cancer cells to predict tumor specific radiosensitivity.

Development and validation of a prognostic nomogram in patients aged ≥65 years with stage I-II non-small cell lung cancer treated with stereotactic body radiotherapy

INTRODUCTION

This study aims to discern the efficacy and toxicity of stereotactic body radiotherapy (SBRT) in older adults with stage I-II non-small cell lung cancer (NSCLC) and establish a prognostic nomogram for these patients.

MATERIALS AND METHODS

One hundred forty-two patients (aged ≥65 years) with clinically-confirmed stage I-II NSCLC treated with SBRT from 2009 to 2020 were enrolled in the study. Primary end points included overall survival (OS), progression free survival (PFS), cumulative incidences of local failure (LF), regional failure (RF), distant failure (DF), and toxicity. A nomogram for OS was developed and validated internally using one thousand bootstrap resamplings.

RESULTS

The median times to LF, RF, and DF were 22.1 months, 26.9 months and 24.1 months, respectively. The 1-, 3-, and 5-year PFS rates from the start of SBRT were 79.4 %, 53.1 %, and 38.9 %, respectively. Performance status, pre-SBRT platelet to lymphocyte ratio (PLR), and planning tumor volume (PTV) were predictive of PFS. The 1-, 3-, and 5-year OS rates from the start of SBRT were 90.8 %, 67.9 % and 47.6 %, respectively. In multivariate analysis, good performance status, a low level of pre-SBRT PLR, and small tumor size were associated with better prognosis, all of which were included in the nomogram. The model showed optimal discrimination, with a C-index of 0.651 and good calibration. The most common adverse reactions were grade 1-2, such as anemia, cough, and fatigue.

DISCUSSION

SBRT is a reasonable treatment modality for early-stage NSCLC in older adults. It achieved good survival outcomes and low toxicity. The proposed nomogram may be able to estimate individual outcomes for these patients.

Survival benefits of radiotherapy in locally advanced unresectable and metastatic pancreatic cancer: a single-institution cohort and SEER database analysis

Background

Chemotherapy (CT) remains the primary treatment for locally advanced unresectable pancreatic cancer (LAUPC) and metastatic pancreatic cancer (MPC). The role of radiotherapy (RT) in these conditions remains unclear. This study compares the outcomes of CT alone versus CT combined with RT (combined-modality therapy [CMT]) in LAUPC and MPC patients.

Materials and methods

We conducted a retrospective analysis of LAUPC and MPC patients treated with either CT or CMT from a single institution and Surveillance, Epidemiology, and End Results (SEER) database. Kaplan-Meier curves and Cox hazards models evaluated the association between treatment modalities and overall survival (OS). Propensity score matching (PSM) ensured balanced comparisons. Landmark analysis addressed immortal time bias. Subgroup analyses were based on clinical characteristics. eXtreme Gradient Boosting (XGBoost) and Shapley Additive Explanations (SHAP) assessed outcome prediction and influence of significant predictors.

Results

The study included 102 patients receiving CMT and 155 receiving CT at single institution, along with 1733 CMT and 9310 CT patients from the SEER dataset. In the single-institution cohort, CMT showed superior survival compared to CT both before (median OS: 20.5 vs. 11.5 months, hazard ratio [HR]: 0.47, 95% CI: 0.34-0.65, P=0.001) and after PSM (median OS: 22.2 vs. 11.8 months, HR: 0.49, 95% CI: 0.30-0.79, P=0.003). Multivariate analyses confirmed that CMT was independently associated with improved OS both before (HR: 0.54, 95% CI: 0.38-0.77, P=0.001) and after PSM (HR: 0.45, 95% CI: 0.27-0.73, P=0.001). Landmark analysis indicated better OS for patients receiving CMT compared to CT alone. Subgroup analysis revealed an OS benefit for CMT across most subgroups. SHAP value analysis indicated that CMT was the most significant contributor to survival outcomes. SEER database validation confirmed these findings.

Conclusions

This study demonstrates that CMT significantly improves OS in LAUPC and MPC patients compared to CT alone. Integrating RT with CT could be beneficial for treating LAUPC and MPC.

Characterization of an oligometastatic state in patients with metastatic pancreatic adenocarcinoma undergoing systemic chemotherapy

PURPOSE/OBJECTIVES

Most patients with pancreatic adenocarcinoma (PDAC) will present with distant metastatic disease at diagnosis. We sought to identify clinical characteristics associated with prolonged overall survival (OS) in patients presenting with metastatic PDAC.

MATERIALS/METHODS

Patients presenting with metastatic PDAC that received treatment at our institution with FOLFIRINOX or gemcitabine-based chemotherapies between August 1, 2011 and September 1, 2017 were included in the study. Metastatic disease burden was comprehensively characterized radiologically via individual diagnostic imaging segmentation. Landmark analysis was performed at 18 months, and survival curves were estimated using the Kaplan-Meier method and compared between groups via the log-rank test. ECOG and Charlson Comorbidity Index (CCI) were calculated for all patients.

RESULTS

121 patients were included with a median age of 62 years (37-86), 40% were female, 25% had ECOG 0 at presentation. Of the 121 patients included, 33% (n = 41) were alive at 12 months and 25% (n = 31) were alive at 18 months. Landmark analysis demonstrated a significant difference between patients surviving <18 months and ≥18 months regarding the presence of lung only metastases (36% vs. 16%, p = 0.04), number of organs with metastases (≥2 vs. 1, p = 0.04), and disease volume (mean of 19.1 cc vs. 1.4 cc, p = 0.04). At Year 1, predictors for improved OS included ECOG status at diagnosis (ECOG 0 vs. ECOG 1, p = 0.04), metastatic disease volume at diagnosis (≤0.1 cc vs. >60 cc, p = 0.004), metastasis only in the liver (p = 0.04), and normalization of CA 19-9 (p < 0.001). At Year 2, the only predictor of improved OS was normalization of the CA 19-9 (p = 0.03). In those patients that normalized their CA 19-9, median overall survival was 16 months.

CONCLUSIONS

In this exploratory analysis normalization of CA-19-9 or volumetric metastatic disease burden less than 0.2 cc demonstrated a remarkable OS, similar to that of patients with non-metastatic disease. These metrics are useful for counseling patients and identifying cohorts that may be optimal for trials exploring metastatic and/or local tumor-directed interventions.

Defining oligometastatic pancreatic cancer: a systematic review and critical synthesis of consensus

BACKGROUND

Small retrospective series suggest that local consolidative treatment (LCT) may improve survival in oligometastatic pancreatic ductal adenocarcinoma (PDAC). However, no uniform definition of oligometastatic disease (OMD) in PDAC exists; this impedes meaningful conclusions.

PATIENTS AND METHODS

A systematic literature search using PubMed, Web of Science, and Cochrane CENTRAL registries for studies and protocols reporting on definitions and/or LCT of OMD in PDAC was performed. The primary endpoint was the definition of OMD. Levels of agreement were categorized as consensus (≥75% agreement between studies), fair agreement (50%-74%), and absent/poor agreement (<50%).

RESULTS

After screening of 5374 abstracts, the full text of 218 studies was assessed, of which 76 were included in the qualitative synthesis. The majority of studies were retrospective (n = 66, 87%), two were prospective studies and eight were study protocols. Studies investigated mostly liver (n = 38, 51%) and lung metastases (n = 15, 20%). Across studies, less than one-half (n = 32, 42%) reported a definition of OMD, while 44 (58%) did not. Involvement was limited to a single organ (consensus). Additional criteria for defining OMD were the number of lesions (consensus), metastatic site (poor agreement), metastatic size (poor agreement), treatment possibilities (poor agreement), and biomarker response (poor agreement). Liver OMD could involve three or fewer lesions (consensus) and synchronous disease (fair agreement), while lung metastases could involve two or fewer lesions and metachronous disease (consensus). The large majority of studies were at a high risk of bias or did not include any control groups.

CONCLUSION

Definitions of OMD were not used or varied widely between studies hampering across-study comparability and highlighting an unmet need for a consensus. The present study is part of a multistep process that aims to develop an interdisciplinary consensus on OMD in pancreatic cancer.

Maintenance Treatment for Metastatic Pancreatic Cancer: Balancing Therapeutic Intensity with Tolerable Toxicity

Metastatic pancreatic ductal adenocarcinoma is typically treated with multi-agent chemotherapy until disease progression or intolerable cumulative toxicity. For patients whose disease shows ongoing control or response beyond a certain timeframe (≥3-4 months), options include pausing chemotherapy with close monitoring or de-escalating to maintenance therapy with the goal of prolonging progression-free and overall survival while preserving quality of life. There is currently no universally accepted standard of care and a relative dearth of randomized clinical trials in the maintenance setting. Conceptually, such therapy can entail continuing the least toxic components of a first-line regimen and/or introducing novel agent(s) such as the poly(ADP-ribose) polymerase inhibitor olaparib, which is presently the only approved drug for maintenance treatment and is limited to a genetically defined subset of patients. In addition to identifying new therapeutic candidates and combinations in the maintenance setting, including targeted agents and immunotherapies, future research should focus on better understanding this unique biologic niche and how treatment in the maintenance setting may be distinct from resistant/refractory disease; identifying molecular predictors for more effective pairing of specific treatments with patients most likely to benefit; and establishing patient-reported outcomes in clinical trials to ensure accurate capture of quality of life metrics.

Early and late recurrence patterns of pancreatic ductal adenocarcinoma after pancreaticoduodenectomy: a multicenter study

BACKGROUND

Survival after pancreaticoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDAC) remains poor because of high incidences of recurrence. The risk factors, patterns, and long-term prognosis in patients with early recurrence and late recurrence (ER and LR) for PDAC after PD were studied.

METHODS

Data from patients who underwent PD for PDAC were analyzed. Recurrence was divided into ER (ER ≤1 years) and LR (LR >1 years) using the time to recurrence after surgery. Characteristics and patterns of initial recurrence, and postrecurrence survival (PRS) were compared between patients with ER and LR.

RESULTS

Among the 634 patients, 281 (44.3%) and 249 (39.3%) patients developed ER and LR, respectively. In the multivariate analysis, preoperative CA19-9 levels, resection margin status, and tumor differentiation were significantly associated with both ER and LR, while lymph node metastasis and perineal invasion were associated with LR. Patients with ER, when compared with patients with LR, showed a significantly higher proportion of liver-only recurrence ( P <0.05), and worse median PRS (5.2 vs. 9.3 months, P <0.001). Lung-only recurrence had a significantly longer PRS when compared with liver-only recurrence ( P <0.001). Multivariate analysis demonstrated that ER and irregular postoperative recurrence surveillance were independently associated with a worse prognosis ( P <0.001).

CONCLUSION

The risk factors for ER and LR after PD are different for PDAC patients. Patients who developed ER had worse PRS than those who developed LR. Patients with lung-only recurrence had a significantly better prognosis than those with other recurrent sites.

Ablative 5-Fraction Stereotactic MRI-Guided Adaptive Radiotherapy for Oligometastatic Pancreatic Adenocarcinoma

INTRODUCTION

Metastatic pancreatic ductal adenocarcinoma (PDAC) carries a poor prognosis and significant morbidity from local tumor progression. We investigated outcomes among oligometastatic PDAC patients treated with stereotactic magnetic resonance image-guided ablative radiotherapy (SMART) to primary disease.

METHODS

We performed a retrospective multi-institutional analysis of oligometastatic PDAC at diagnosis or with metachronous oligoprogression during induction chemotherapy treated with primary tumor SMART. Outcomes of interest included overall survival (OS), progression-free survival (PFS), freedom from locoregional failure (FFLRF), and freedom from distant failure (FFDF). Acute and late toxicity were reported and in exploratory analyses patients were stratified by the number of metastases, SMART indication, and addition of metastasis-directed therapy.

RESULTS

From 2019 to 2021, 22 patients with oligometastatic PDAC (range: 1-6 metastases) received SMART to the primary tumor with a median follow-up of 11.2 months from SMART. Nineteen patients had de novo synchronous metastatic disease and three had metachronous oligoprogression. Metastasis location most commonly was liver only (40.9%), multiple organs (27.3%), lungs only (13.6%), or abdominal/pelvic nodes (13.6%). All patients received either FOLFIRINOX (64%) or gemcitabine/nab-paclitaxel (36%) followed by SMART (median 50 Gy, 5 fractions) for local control (77%), pain control (14%), or local progression (9%). Additionally, 41% of patients received other metastasis-directed treatments. The median OS from diagnosis and SMART was 23.9 months and 11.6 months, respectively. Calculated from SMART, the median PFS was 2.4 months with 91% of patients having distant progression, and 1-year local control was 68. Two patients (9%) experienced grade 3 toxicities, gastric outlet obstruction, and gastrointestinal bleed without grade 4 or 5 toxicity.

CONCLUSION

There was minimal morbidity of local disease progression after SMART in this cohort of oligometastatic PDAC. As systemic therapy options improve, additional strategies to identify patients who may derive benefits from local consolidation or metastasis-directed therapy are needed.

The Effectiveness of Chemoradiotherapy in Elderly Patients with Pancreatic Cancer: A Population-Based Study Based on the SEER Database

INTRODUCTION

Chemotherapy (CT) is the main treatment for patients with unresected pancreatic cancer (PC). Whether the addition of radiotherapy to chemotherapy improves the prognosis of elderly patients with unresected PC is unclear. The aim of our study was to compare the efficacy of chemoradiotherapy (CRT) with chemotherapy alone in elderly patients with unresected PC.

METHODS

The clinical data of elderly patients with unresected PC who received chemotherapy between 2004 and 2017 were determined from the Surveillance, Epidemiology, and End Results (SEER) database, and the patients were divided into CT and CRT groups. The primary outcome was overall survival (OS), and secondary endpoints were cancer-specific survival (CSS) and cancer-specific mortality (CSM). Propensity matching analysis (PSM) was used to balance the differences between the two groups. OS and CSS were assessed using Kaplan-Meier analysis, while CSM was assessed using a competing risk model. Subgroup analyses were also performed, and Cox regression was used to adjust for confounding factors.

RESULTS

A total of 17,814 patients were diagnosed with PC including 14,222 who received CT alone and 3592 who received CRT. The 1-year OS of the CT and CRT groups after PSM was 30.1% and 40.8%, and the 1-year CSS was 31.4% and 42.1%, respectively. Overall, the CRT group had better OS, CSS, and CSM rates than the CT group before and after PSM (P < 0.05). After adjustment for age, sex, race, histological grade, stage, and other factors, the CRT group still had a lower risk of death than the CT group, and subgroup analysis further revealed the survival benefit of CRT in each population.

CONCLUSIONS

CRT improves the outcome of patients with non-surgical PC over 65 years of age. But prospective studies are needed to validate our results.

Role of Local Treatment for Oligometastasis: A Comparability-Based Meta-Analysis

PURPOSE

We intend to investigate the oncological efficacy and feasibility of local consolidative therapy (LCT) through a meta-analysis method.

MATERIALS AND METHODS

Four databases including PubMed, MEDLINE, Embase, and Cochrane library were searched. Target studies are controlled trials comparing outcomes of LCT versus a control group. Primary endpoints are overall survival (OS) and progression-free survival (PFS).

RESULTS

A total of 54 studies involving 7,242 patients were included. Pooled analyses showed that the LCT arm could achieve improved OS with pooled odds ratio of 2.896 (95% confidence interval [CI], 2.377 to 3.528; p < 0.001). Regarding PFS, pooled analyses showed pooled odds ratio of 3.045 (95% CI, 2.356 to 3.937; p < 0.001) in favor of the LCT arm. In the subgroup analyses including the studies with reliable comparability (e.g. randomized studies or intentionally matched studies without significant favorable prognosticator in LCT arms), pooled odds ratio was 2.548 (95% CI, 1.808 to 3.591; p < 0.001) favoring the LCT arm regarding OS. Regarding PFS, pooled OR was 2.656 (95% CI, 1.713 to 4.120; p < 0.001) which also favored the LCT arm. Subgroup analyses limited to the randomized controlled trials (RCT) were also performed and pooled odds ratios on OS and PFS were 1.535 (95% CI, 1.082 to 2.177; p=0.016) and 1.668 (95% CI, 1.187 to 2.344; p=0.003). The rates of grade ≥ 3 complications related to LCT was mostly low (< 10%) and not significantly higher compared to the control arm.

CONCLUSION

Pooled analyses results of all included studies, selected studies with reliable comparability, and RCT's demonstrated the survival benefit of LCT. These consistent results suggest that LCT was beneficial to the patients with oligometastasis.

Surgical management of pancreatic cancer liver oligometastases

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer, which commonly metastasizes to the liver. The current standard of care for metastatic PDAC is systemic chemotherapy, however there are limited emerging data regarding surgical resection of pancreatic oligometastases in select patients. Here we review the literature addressing resection of PDAC liver oligometastases.