Impact of neoadjuvant chemotherapy and stereotactic body radiation therapy (SBRT) on R0 resection rate for borderline resectable and locally advanced pancreatic cancer

Stereotactic body radiotherapy in pancreatic adenocarcinoma

BACKGROUND

Stereotactic body radiotherapy (SBRT) in pancreatic cancer allows high delivery of radiation doses on tumors without affecting surrounding tissue. This review aimed at the SBRT application in the treatment of pancreatic cancer.

DATA SOURCES

We retrieved articles published in MEDLINE/PubMed from January 2017 to December 2022. Keywords used in the search included: "pancreatic adenocarcinoma" OR "pancreatic cancer" AND "stereotactic ablative radiotherapy (SABR)" OR "stereotactic body radiotherapy (SBRT)" OR "chemoradiotherapy (CRT)". English language articles with information on technical characteristics, doses and fractionation, indications, recurrence patterns, local control and toxicities of SBRT in pancreatic tumors were included. All articles were assessed for validity and relevant content.

RESULTS

Optimal doses and fractionation have not yet been defined. However, SBRT could be the standard treatment in patients with pancreatic adenocarcinoma in addition to CRT. Furthermore, the combination of SBRT with chemotherapy may have additive or synergic effect on pancreatic adenocarcinoma.

CONCLUSIONS

SBRT is an effective modality for patients with pancreatic cancer, supported by clinical practice guidelines as it has demonstrated good tolerance and good disease control. SBRT opens a possibility of improving outcomes for these patients, both in neoadjuvant treatment and with radical intent.

Safety and Efficacy of Neoadjuvant SABR in Pancreatic Cancer: Effect of Magnetic Resonance Imaging-Guided Respiratory-Gated Adaptive Radiation Therapy

Purpose

We aimed to evaluate the safety and efficacy of neoadjuvant SABR using magnetic resonance imaging-guided respiratory-gated adaptive radiation therapy (MRgRg-ART) in pancreatic cancer.

Methods and Materials

We performed a single-institution retrospective review in patients with pancreatic cancer who underwent neoadjuvant SABR followed by surgical resection. After neoadjuvant chemotherapy, those considered resectable by the multidisciplinary team received SABR over 5 consecutive days using MRgRg-ART. Factors associated with severe postoperative complications (Clavien-Dindo grade ≥III) and prognostic factors for overall survival were analyzed.

Results

Sixty-two patients were included in the analysis, with a median follow-up of 10.3 months. The median prescribed dose to the planning target volume was 50 Gy. Fifty-two (85.3%) patients underwent R0 resection, and 11 (18.0%) experienced severe postoperative complications. No factors were associated with the incidence of severe postoperative complications. There were 3 cases of locoregional recurrence, resulting in a 12-month local control rate of 93.1%. Elevated postoperative carbohydrate antigen 19-9 was significantly associated with poor overall survival in the multivariate analysis (P = .037).

Conclusions

Neoadjuvant SABR with 50 Gy using MRgRg-ART delivered to pancreatic cancer resulted in a notable survival outcome with acceptable toxicities. Further studies are warranted to investigate the long-term effects of this method.

Comprehensive multimodal management of borderline resectable pancreatic cancer: Current status and progress

Borderline resectable pancreatic cancer (BRPC) is a complex clinical entity with specific biological features. Criteria for resectability need to be assessed in combination with tumor anatomy and oncology. Neoadjuvant therapy (NAT) for BRPC patients is associated with additional survival benefits. Research is currently focused on exploring the optimal NAT regimen and more reliable ways of assessing response to NAT. More attention to management standards during NAT, including biliary drainage and nutritional support, is needed. Surgery remains the cornerstone of BRPC treatment and multidisciplinary teams can help to evaluate whether patients are suitable for surgery and provide individualized management during the perioperative period, including NAT responsiveness and the selection of surgical timing.

Feasibility, safety, and efficacy of stereotactic body radiotherapy combined with intradermal heat-killed mycobacterium obuense (IMM-101) vaccination for non-progressive locally advanced pancreatic cancer, after induction chemotherapy with (modified)FOLFIRINOX - The LAPC-2 trial

BACKGROUND AND PURPOSE

In this phase I/II trial, non-progressive locally advanced pancreatic cancer (LAPC) patients after (modified)FOLFIRINOX therapy were treated with stereotactic body radiotherapy (SBRT) combined with heat-killed mycobacterium (IMM-101) vaccinations. We aimed to assess safety, feasibility, and efficacy of this treatment approach.

MATERIALS AND METHODS

On five consecutive days, patients received a total of 40 Gray (Gy) of SBRT with a dose of 8 Gy per fraction. Starting two weeks prior to SBRT, they in addition received six bi-weekly intradermal vaccinations with one milligram of IMM-101. The primary outcomes were the number of grade 4 or higher adverse events and the one-year progression free-survival (PFS) rate.

RESULTS

Thirty-eight patients were included and started study treatment. Median follow-up was 28.4 months (95 %CI 24.3 - 32.6). We observed one grade 5, no grade 4 and thirteen grade 3 adverse events, none related to IMM-101. The one-year PFS rate was 47 %, the median PFS was 11.7 months (95 %CI 11.0 - 12.5) and the median overall survival was 19.0 months (95 %CI 16.2 - 21.9). Eight (21 %) tumors were resected, of which 6 (75 %) were R0 resections. Outcomes were comparable with the outcomes of the patients from the previous LAPC-1 trial, in which LAPC patients were treated with SBRT, without IMM-101.

CONCLUSION

Combination treatment with IMM-101 and SBRT was safe and feasible for non-progressive locally advanced pancreatic cancer patients after (modified)FOLFIRINOX. No improvement in the progression-free survival could be demonstrated by adding IMM-101 to SBRT.

Vasculitis, CA19-9, and Perineural Invasion Differentially Predict Response and Surgical Outcome in Pancreatic Ductal Adenocarcinoma

PURPOSE

Curative intent treatment of pancreatic adenocarcinoma (PDAC) relies on surgical resection. Modern treatment protocols focus on optimizing neoadjuvant therapy to increase resectability and improve oncologic outcomes. To elucidate differences in outcomes, we investigated the relationship between neoadjuvant chemotherapy (NAC), either with or without stereotactic body radiation therapy (SBRT), and vascular inflammation, surgical outcomes, and the resultant transcriptomic changes.

METHODS AND MATERIALS

Clinical data were collected from patients with borderline resectable PDAC (clinical T3-T4N0-1) who underwent NAC or NAC-SBRT followed by curative intent resection between 2014 and 2019. Vascular structures on surgical specimens were histologically evaluated for vasculitis. RNA sequencing was used to evaluate differential gene expression and to generate enrichment maps. Multivariate analysis was used to analyze the relationship between patient characteristics and oncological outcome.

RESULTS

In total, 46 patients met inclusion criteria (n = 12 NAC, n = 34 NAC-SBRT) with a median follow-up of 20.1 months. All patients underwent curative resection, with 91.3% achieving R0. There was no significant difference in patterns of failure, overall survival, or progression-free survival between NAC and NAC-SBRT groups. Patients with vasculitis had a lower median overall survival compared with those without (14.5 vs 28.3 months; hazard ratio, 12.96; 95% confidence interval, 3.55-47.28; P < .001). There was no significant correlation between inflammation and surgical complications or pathologic response. Neoadjuvant therapy did not have a significant effect on development of vasculitis (odds radio, 1.64 for NAC-SBRT; 95% confidence interval, 0.40-8.43; P = .52). Predictors of poor survival included perineural invasion and high baseline carbohydrate antigen 19-9 (CA19-9) (>191 U/mL). Patients with robust CA19-9 (>20% decrease) responses to neoadjuvant therapy had enrichment in immune response, chemotaxis, and cytotoxic T-cell and natural killer-cell proliferation.

CONCLUSIONS

Vasculitis predicts for poor survival outcomes in patients with PDAC; NAC-SBRT did not increase the rate of vasculitis compared with NAC. Perineural invasion and CA19-9 remain strong prognosticators. Understanding and optimizing immune interactions remain a crucial hurdle in achieving response in pancreatic cancer.

FDG-PET Predicts Neoadjuvant Therapy Response and Survival in Borderline Resectable/Locally Advanced Pancreatic Adenocarcinoma

BACKGROUND

Neoadjuvant therapy (NAT) is used in borderline resectable/locally advanced (BR/LA) pancreatic ductal adenocarcinoma (PDAC). Anatomic imaging (CT/MRI) poorly predicts response, and biochemical (CA 19-9) markers are not useful (nonsecretors/nonelevated) in many patients. Pathologic response highly predicts survival post-NAT, but is only known postoperatively. Because metabolic imaging (FDG-PET) reveals primary tumor viability, this study aimed to evaluate our experience with preoperative FDG-PET in patients with BR/LA PDAC in predicting NAT response and survival.

METHODS

We reviewed all patients with resected BR/LA PDAC who underwent NAT with FDG-PET within 60 days of resection. Pre- and post-NAT metabolic (FDG-PET) and biochemical (CA 19-9) responses were dichotomized in addition to pathologic responses. We compared post-NAT metabolic and biochemical responses as preoperative predictors of pathologic responses and recurrence-free survival (RFS) and overall survival (OS).

RESULTS

We identified 202 eligible patients. Post-NAT, 58% of patients had optimization of CA 19-9 levels. Major metabolic and pathologic responses were present in 51% and 38% of patients, respectively. Median RFS and OS times were 21 and 48.7 months, respectively. Metabolic response was superior to biochemical response in predicting pathologic response (area under the curve, 0.86 vs 0.75; P<.001). Metabolic response was the only univariate preoperative predictor of OS (odds ratio, 0.25; 95% CI, 0.13-0.40), and was highly correlated (P=.001) with pathologic response as opposed to biochemical response alone. After multivariate adjustment, metabolic response was the single largest independent preoperative predictor (P<.001) for pathologic response (odds ratio, 43.2; 95% CI, 16.9-153.2), RFS (hazard ratio, 0.37; 95% CI, 0.2-0.6), and OS (hazard ratio, 0.21; 95% CI, 0.1-0.4).

CONCLUSIONS

Among patients with post-NAT resected BR/LA PDAC, FDG-PET highly predicts pathologic response and survival, superior to biochemical responses alone. Given the poor ability of anatomic imaging or biochemical markers to assess NAT responses in these patients, FDG-PET is a preoperative metric of NAT efficacy, thereby allowing potential therapeutic alterations and surgical treatment decisions. We suggest that FDG-PET should be an adjunct and recommended modality during the NAT phase of care for these patients.

Pathological and surgical outcomes of pancreatic adenocarcinoma (PA) after pre-operative ablative stereotactic magnetic resonance image-guided adaptive radiotherapy (A-SMART)

Purpose

Preoperative radiation therapy (RT) for pancreatic adenocarcinoma reduces positive surgical margin rates, and when delivered to an ablative dose range it may improve local control and overall survival for patients with unresectable disease. Use of stereotactic body RT to achieve a higher biologically effective dose has been limited by toxicity to adjacent radiosensitive structures, but this can be mitigated by stereotactic magnetic resonance image guided adaptive radiation therapy (SMART).

Methods and Materials

We describe our single-institution experience of high biologically effective dose SMART before resection of localized pancreatic adenocarcinoma. Toxicity was evaluated according to Common Terminology Criteria for Adverse Events (V 5.0). Tumor response was evaluated according to the College of American Pathologists tumor regression grading criteria.

Results

We analyzed 26 patients with borderline resectable (80.8%), locally advanced (11.5%), and resectable (7.7%) tumors who received ablative dose SMART (A-SMART) followed by surgical resection. Median age at diagnosis was 68 years (range, 34-86). Most patients received chemotherapy (80.8%) before RT. All patients received A-SMART to a median dose of 50 (range, 40-50) Gy in 5 fractions. Toxicity data were collected prospectively and there were no acute grade 2+ toxicities associated with RT. The median time to resection was 50 days (range, 37-115), and the procedure types included Whipple (69%), distal (23%), or total pancreatectomy (8%). The R0 resection rate was 96% and no perioperative deaths occurred within 90 days. Pathologic response was observed in 88% of cases. The time from RT to surgery was associated with tumor regression grade (P = .0003). The median follow-up after RT was 16.5 months (range, 3.9-26.2). The derived median progression-free survival from RT was 13.2 months.

Conclusions

The initial surgical and pathologic outcomes after A-SMART are encouraging. Preoperative A-SMART was associated with low toxicity rates and no surgical or RT-associated mortality. The surgical morbidity was comparable to historic rates after upfront resection. These data also suggest that the time from stereotactic body RT to surgical resection is associated with pathologic response.

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.

Clinical challenges associated with utility of neoadjuvant treatment in patients with pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is an increasingly common cancer with a persistently poor prognosis, and only approximately 20% of patients are clearly anatomically resectable at diagnosis. Historically, a paucity of effective therapy made it inappropriate to forego the traditional gold standard of upfront surgery in favour of neoadjuvant treatment; however, modern combination chemotherapy regimens have made neoadjuvant therapy increasingly viable. As its use has expanded, the rationale for neoadjuvant therapy has evolved from one of 'downstaging' to one of early treatment of micro-metastases and selection of patients with favourable tumour biology for resection. Defining resectability in PDAC is problematic; multiple differing definitions exist. Multidisciplinary input, both in initial assessment of resectability and in supervision of multimodality therapy, is therefore advised. European and North American guidelines recommend the use of neoadjuvant chemotherapy in borderline resectable (BR)-PDAC. Similar regimens may be applied in locally advanced (LA)-PDAC with the aim of improving potential access to curative-intent resection, but appropriate patient selection is key due to significant rates of recurrence after excision of LA disease. Upfront surgery and adjuvant chemotherapy remain standard-of-care in clearly resectable PDAC, but multiple trials evaluating the use of neoadjuvant therapy in this and other localised settings are ongoing.

Comparing neoadjuvant chemotherapy with or without radiation therapy for pancreatic ductal adenocarcinoma: National Cancer Database cohort analysis

BACKGROUND

Neoadjuvant treatment is important for improving the rate of R0 surgical resection and overall survival outcome in treating patients with pancreatic ductal adenocarcinoma (PDAC). However, the true efficacy of radiotherapy (RT) for neoadjuvant treatment of PDAC is uncertain. This retrospective study evaluated the treatment outcome of neoadjuvant RT in the treatment of PDAC.

METHODS

Collected from the National Cancer Database, information on patients with PDAC who underwent neoadjuvant chemotherapy (NAC) and pancreatectomy between 2010 to 2016 was used in this study. Short- and long-term outcomes were compared between patients who received neoadjuvant chemoradiotherapy (NACRT) and NAC.

RESULTS

The study included 6936 patients, of whom 3185 received NACRT and 3751 NAC. The groups showed no difference in overall survival (NACRT 16.1 months versus NAC 17.4 months; P = 0.054). NACRT is associated with more frequent margin negative resection (86.1 versus 80.0 per cent; P < 0.001) but a more unfavourable 90-day mortality than NAC (6.4 versus 3.6 per cent; P < 0.001). The odds of 90-day mortality were higher in the radiotherapy group (odds ratio 1.81; P < 0.001), even after adjusting for significant covariates. Patients who received NACRT received single-agent chemotherapy more often than those who received NAC (31.5 versus 10.7 per cent; P < 0.001).

CONCLUSION

This study failed to show a survival benefit for NACRT over NAC alone, despite its association with negative margin resection. The significantly higher mortality in NACRT warrants further investigation into its efficacy in the treatment of pancreatic cancer.

High local failure rates despite high margin-negative resection rates in a cohort of borderline resectable and locally advanced pancreatic cancer patients treated with stereotactic body radiation therapy following multi-agent chemotherapy

BACKGROUND

Stereotactic body radiation therapy (SBRT) for patients with borderline resectable and locally advanced pancreatic adenocarcinoma (BRPC/LAPC) remains controversial. Herein, we report on surgical, pathologic, and survival outcomes in BRPC/LAPC patients treated at a high-volume institution with induction chemotherapy (CTX) followed by 5-fraction SBRT.

METHODS

BRPC/LAPC patients treated between 2016 and 2019 were retrospectively reviewed. Surgical and pathological outcomes were descriptively characterized. Overall survival (OS) and progression-free survival (PFS) were analyzed using Cox proportional hazard regression. Locoregional failure and distant failure were analyzed with Fine-Gray competing risk model.

RESULTS

Of 155 patients, 91 (59%) had LAPC and 64 (41%) had BRPC. Almost all were treated with induction multi-agent CTX with either FOLFIRINOX (75%) or gemcitabine and nab-paclitaxel (24%) for a median duration of 4.0 months (1-18 months). All received SBRT to a median dose of 33 Gy. Among 64 BRPC patients, 50 (78%) underwent resection, of whom 48 (96%) achieved margin-negative (R0) resection. Among 91 LAPC patients, 57 (63%) underwent resection, of whom 50 (88%) achieved R0 resection. Despite the high R0 rate, 33% of patients experienced locoregional failure, which was a component of 44% of all failures. After SBRT, median OS and PFS were 18.7 and 7.7 months, respectively. After SBRT, 1- and 2-year OS probabilities were 70% and 45%, whereas, from diagnosis, they were 93% and 51%.

CONCLUSIONS

Although a high proportion of BRPC/LAPC patients treated with induction multi-agent CTX followed by SBRT successfully achieved R0 resection, locoregional failure remained common, highlighting the need to continue to optimize radiation delivery in this context.

Added Value of Radiotherapy Following Neoadjuvant FOLFIRINOX for Resectable and Borderline Resectable Pancreatic Cancer: A Systematic Review and Meta-Analysis

Background

The added value of radiotherapy following neoadjuvant FOLFIRINOX chemotherapy in patients with resectable or borderline resectable pancreatic cancer ((B)RPC) is unclear. The objective of this meta-analysis was to compare outcomes of patients who received neoadjuvant FOLFIRINOX alone or combined with radiotherapy.

Methods

A systematic literature search was performed in Embase, Medline (ovidSP), Web of Science, Scopus, Cochrane, and Google Scholar. The primary endpoint was pooled median overall survival (OS). Secondary endpoints included resection rate, R0 resection rate, and other pathologic outcomes.

Results

We included 512 patients with (B)RPC from 15 studies, of which 7 were prospective nonrandomized studies. In total, 351 patients (68.6%) were treated with FOLFIRINOX alone (8 studies) and 161 patients (31.4%) were treated with FOLFIRINOX and radiotherapy (7 studies). The pooled estimated median OS was 21.6 months (range 18.4–34.0 months) for FOLFIRINOX alone and 22.4 months (range 11.0–37.7 months) for FOLFIRINOX with radiotherapy. The pooled resection rate was similar (71.9% vs. 63.1%, p = 0.43) and the pooled R0 resection rate was higher for FOLFIRINOX with radiotherapy (88.0% vs. 97.6%, p = 0.045). Other pathological outcomes (ypN0, pathologic complete response, perineural invasion) were comparable.

Conclusions

In this meta-analysis, radiotherapy following neoadjuvant FOLFIRINOX was associated with an improved R0 resection rate as compared with neoadjuvant FOLFIRINOX alone, but a difference in survival could not be demonstrated. Randomized trials are needed to determine the added value of radiotherapy following neoadjuvant FOLFIRINOX in patients with (B)PRC.

Supplementary Information

The online version contains supplementary material available at 10.1245/s10434-021-10276-8.