Pathologic complete response to neoadjuvant therapy in patients with pancreatic ductal adenocarcinoma is associated with a better prognosis

Moving From the Background Toward the Spotlight: A Critical Review of Radiation Therapy for Locally Advanced Pancreas Cancer

Radiation therapy (RT) for locally advanced pancreatic cancer (LAPC) continues to be controversial. Advances in both systemic therapy and RT techniques have changed the landscape of LAPC management in recent years. Clinical outcomes of ablative RT have been encouraging, and randomized clinical trials may clarify the role of RT for LAPC. We present a contemporary critical review of key aspects regarding optimal patient selection, radiation dose escalation techniques, novel radiosensitizers and radioprotectors, and treatment response assessment for LAPC.

Metabolic response during preoperative chemotherapy can predict prognosis in pancreatic cancer

BACKGROUND

With the evolving treatment paradigms for pancreatic cancer, there is an increasing need for reliable markers to evaluate the effectiveness of preoperative chemotherapy. Due to the limitations of current indicators, this study aimed to evaluate the prognostic value of metabolic response based on the changes in the maximum standardized uptake value (SUVmax) on fluorine-18-fluorodeoxyglucose positron emission tomography.

METHODS

This study included 210 patients with pancreatic cancer who underwent post-chemotherapy curative surgery between 2013 and 2022. Using maximally selected rank statistics for survival, the metabolic response was defined as follows: metabolic responder (%ΔSUVmax >75%), metabolic stable disease (15%-75%), and metabolic non-responder (≤15%).

RESULTS

Among patients, 15.7%, 66.7%, and 11.6% were categorized into the metabolic responder, metabolic stable disease, and metabolic non-responder groups. The metabolic responder group (83.0 months) had longer median overall survival than the metabolic stable disease (51.0 months, p = .013) and metabolic non-responder (32.0 months, p = .002) groups. In addition, being metabolic responders (vs. non-responders) was an independent predictor of low recurrence rates (hazard ratio [95% confidence interval]: 0.46 [0.23-0.91]; p = .026) and achieving pathologic complete response (odds ratio [95% confidence interval]: 13.39 [1.61-300.77]; p = .035).

CONCLUSIONS

Metabolic response during preoperative chemotherapy has predictive power for post-resection prognosis and residual tumor status.

Role of volumetric tumor enhancement on CT in predicting overall survival in patients with unresectable pancreatic ductal adenocarcinoma

PURPOSE

To assess the utility of volumetric tumor enhancement on CT to predict tumor treatment response and the overall survival (OS) of patients with PDAC undergoing FOLFIRINOX-based systemic chemotherapy. Additionally, we aim to explore the performance of a novel model that incorporates relevant volumetric CT-derived parameters to the established RECIST 1.1 in predicting both treatment response and OS.

MATERIAL AND METHODS

In this retrospective single-institution study, 127 patients with PDAC who received FOLFIRINOX neoadjuvant chemotherapy between December 2012 and November 2021 were included. Manual volumetric segmentation of the single largest tumor was performed on portal venous phase images. Total and enhancing tumor volumes were calculated. Response by RECIST 1.1 was compared to response by tumor volume and enhancing tumor volume on follow-up CT.

RESULTS

There was no association between overall survival and RECIST 1.1 (p-value = 0.284), volumetric RECIST (p-value = 0.402), and other volumetric CT variables, except for a percentage reduction in enhancing tumor volume (p-value = 0.043). Using univariate survival analysis for categorical thresholds defined by CART, the percentage change in enhancing tumor volume was associated with OS (p-value = 0.018). There was also a significant association between baseline enhancing tumor volume and OS (p-value <0.0001). Using these two categories, we defined a multivariable model associated with OS (p-value <0.0001).

CONCLUSION

Percentage reduction in enhancing tumor volume was related to OS in non-surgical PDAC patients treated with FOLFIRINOX chemotherapy and could potentially be incorporated into patient survival prediction models.

Pathologic complete response following neoadjuvant chemotherapy in pancreatic ductal adenocarcinoma: Impact on survival and recurrence

BACKGROUND

Pathologic complete response after neoadjuvant treatment in pancreatic ductal adenocarcinoma is a rare occurrence. Similar to other malignancies, achieving a pathologic complete response in pancreatic ductal adenocarcinoma seems to correlate with improved survival. However, because of the rarity of such events, the true significance of pathologic complete response in pancreatic cancer remains unclear. The aim of the present study was to investigate the impact of pathologic complete response on survival and recurrence.

METHODS

In a single-center retrospective study, pathologic complete response was defined as no evidence of viable tumor cells in resected specimen entirely sampled according to a rigorous protocol and in which a residual tumor bed was identified. Disease-specific survival and disease-free survival were measured from surgery. Independent predictors for disease-specific survival and disease-free survival were examined.

RESULTS

Overall, 403 patients were included. Pathologic complete response was found in 15 patients (3.8%), after chemotherapy alone. After a median follow-up of 42 months (95% CI 38-45), 3-year disease-specific survival was 87% in pathologic complete response patients vs 43% in those without pathologic complete response (P = .014). The recurrence rate was 40% (n = 6/15) in the pathologic complete response group compared with 69.8% (n = 271/388) in those without pathologic complete response. Disease-free survival was longer in the pathologic complete response group, with higher 1- and 3-year rates compared with the no-pathologic complete response group (80% vs 60% and 48% vs 24%, respectively). Pathologic complete response was found to be an independent protective factor for disease-specific survival (P = .035) but not for disease-free survival (P = .052).

CONCLUSION

Pathologic complete response in pancreatic ductal adenocarcinoma is not synonymous of cure but ensure a prolonged survival. Nevertheless, recurrence remains a significant concern, with high rates observed even among these exceptional responders.

Prognostic impact of the distance from the anterior surface to tumor cells in pancreatoduodenectomy with neoadjuvant chemoradiotherapy for pancreatic ductal adenocarcinoma

PURPOSE

Several reports have shown the importance of margins in pancreatoduodenectomy (PD) specimens; however, whether anterior surfaces are included as margins varies among reports. In this study, we aimed to examine the impact of the anterior surface on disease-free survival (DFS) and overall survival (OS).

METHOD

In total, 98 patients who underwent PD after chemoradiotherapy for pancreatic ductal adenocarcinoma at Mie University Hospital between January 1, 2012, and December 31, 2019, were included. We investigated the prognostic impact of the distance from the anterior surface to tumor cells on DFS and OS using a log-rank test. Multivariate analysis was performed using Cox proportional hazards analysis.

RESULTS

A significant difference in DFS and OS was observed up to a distance of 5 mm from the anterior surface of tumor cells. The multivariate analysis revealed that the distance from the anterior surface to tumor cells (≤5 mm) was an independent poor prognostic factor for DFS and OS.

CONCLUSION

In patients with PD treated with neoadjuvant therapy, the distance from the anterior surface to tumor cells is an important assessment and should be included in the pathology report.

Rectal Cancer Survival for Residual Carcinoma In Situ Versus Pathologic Complete Response After Neoadjuvant Therapy

BACKGROUND

Pathologic complete response after neoadjuvant chemoradiotherapy for rectal cancer is associated with improved survival. It is unclear whether residual carcinoma in situ portends a similar outcome.

OBJECTIVE

To compare the survival of patients with locally advanced rectal cancer who received neoadjuvant therapy and achieved pathologic carcinoma in situ versus pathologic complete response.

DESIGN

Retrospective cohort study.

SETTING

National public database.

PATIENTS

A total of 4594 patients in the National Cancer Database from 2006 to 2016 with locally advanced rectal cancer who received neoadjuvant therapy, underwent surgery, and had node-negative ypTis or ypT0 on final pathology were included. Of these, 4321 patients (94.1%) had ypT0 and 273 (5.9%) had ypTis on final pathology.

MAIN OUTCOME MEASURE

Overall survival.

RESULTS

The median age was 60 years, and 1822 patients (39.7%) were women. On initial staging, 54.5% (n = 2503) had stage II disease and 45.5% (n = 2091) had stage III disease. The ypTis group had decreased overall survival compared to the ypT0 group (HR 1.42; 95% CI, 1.04-1.95; p  = 0.028). Other factors associated with decreased overall survival were older age at diagnosis, increasing Charlson-Deyo score, and poorly differentiated tumor grade. Variables associated with improved survival were female sex, private insurance, and receipt of both neoadjuvant and adjuvant chemotherapy. For the total cohort, there was no difference in survival between clinical stage II and stage III.

LIMITATIONS

Standard therapy versus total neoadjuvant therapy could not be abstracted. Overall survival was defined as the time from surgery to death from any cause or last contact, allowing for some erroneously misclassified deaths.

CONCLUSIONS

ypTis is associated with worse overall survival than ypT0 for patients with locally advanced rectal cancer who receive neoadjuvant chemoradiotherapy followed by surgery. For this cohort, clinical stage was not a significant predictor of survival. Prospective trials comparing survival for these pathologic outcomes are needed. See Video Abstract .

SUPERVIVENCIA DEL CNCER DE RECTO PARA EL CARCINOMA RESIDUAL IN SITU VS RESPUESTA PATOLGICA COMPLETA DESPUS DE LA TERAPIA NEOADYUVANTE

ANTECEDENTESLa respuesta patológica completa después de la quimiorradioterapia neoadyuvante para el cáncer de recto se asocia con una mayor supervivencia. No está claro si el carcinoma residual in situ presagia un resultado similar.OBJETIVOComparar la supervivencia de pacientes con cáncer de recto localmente avanzado que recibieron terapia neoadyuvante y lograron un carcinoma patológico in situ versus una respuesta patológica completa.DISEÑOEstudio de cohorte retrospectivo.ESCENARIOBase de datos pública nacional.PACIENTESSe incluyeron 4,594 pacientes de la Base de Datos Nacional de Cáncer de 2006 a 2016 con cáncer de recto localmente avanzado que recibieron terapia neoadyuvante, fueron sometidos a cirugía y tuvieron ganglios negativos, ypTis o ypT0 en el reporte patológico final. 4.321 (94,1%) tuvieron ypT0 y 273 (5,9%) tuvieron ypTis en el reporte final.PRINCIPALES MEDIDAS DE RESULTADOSupervivencia general.RESULTADOSLa mediana de edad fue de 60 años. 1.822 pacientes (39,7%) fueron mujeres. El 54,5% (n = 2.503) tuvo la enfermedad en estadio II y el 45,5% (n = 2.091) tuvo la enfermedad en estadio III según la estadificación inicial. El grupo ypTis tuvo una supervivencia general reducida en comparación con el grupo ypT0 (HR 1,42, IC 95 % 1,04-1,95, p = 0,028). Otros factores asociados con una menor supervivencia general fueron una edad más avanzada al momento del diagnóstico, un aumento de la puntuación de Charlson-Deyo y un grado tumoral poco diferenciado. Las variables asociadas con una mejor supervivencia fueron el sexo femenino, el seguro privado y la recepción de quimioterapia neoadyuvante y adyuvante. Para la cohorte total, no hubo diferencias en la supervivencia entre el estadio clínico 2 y el estadio 3.LIMITACIONESNo se pudo resumir el tratamiento estándar versus el tratamiento neoadyuvante total. La supervivencia general se definió como el tiempo transcurrido desde la cirugía hasta la muerte por cualquier causa o último contacto, lo que permite algunas muertes erróneamente clasificadas.CONCLUSIONESypTis se asocia con una peor supervivencia general que ypT0 en pacientes con cáncer de recto localmente avanzado que reciben quimiorradioterapia neoadyuvante seguida de cirugía. Para esta cohorte, el estadio clínico no fue un predictor significativo de supervivencia. Se necesitan ensayos prospectivos que comparen la supervivencia de estos resultados patológicos. ( Traducción-Dr Osvaldo Gauto ).

Microscopic tumor mapping of post-neoadjuvant therapy pancreatic cancer specimens to predict post-surgical recurrence: A prospective cohort study

BACKGROUND

Although various pathological grading systems are available for evaluating the response of pancreatic ductal adenocarcinoma (PDAC) to neoadjuvant therapy (NAT), their prognostic value has not been thoroughly validated. This study examined whether microscopic tumor mapping of post-NAT specimens could predict tumor recurrence.

METHODS

This prospective study enrolled 52 patients who underwent pancreaticoduodenectomy after NAT for PDAC between 2019 and 2021. Microscopic mapping was performed to identify residual tumor loci within the tumor bed using 4 mm2 pixels. Patients were divided into small extent (SE; n = 26) and large extent (LE; n = 26) groups using a cutoff value of 226 mm2. The diagnostic performance for predicting tumor recurrence was evaluated using receiver operating characteristic (ROC) curves.

RESULTS

Carbohydrate antigen 19-9 levels were normalised after NAT in more patients in the SE group (SE 21 [80.8%] vs. LE 13 [50.0%]; P = 0.041). Tumor size (P < 0.001), T stage (P < 0.001), positive lymph node yield (P = 0.024), and perineural invasion rate (P = 0.018) were significantly greater in the LE group. The 3-year disease-free survival rate was significantly lower in the LE group (SE 83.3% vs. LE 50.0%, P = 0.004). The area under the ROC curve for mapping extent was 0.743, which was greater than that of the other tumor response scoring systems.

CONCLUSIONS

Microscopic tumor mapping of the residual tumor in post-NAT specimens is a significant predictor of post-surgical recurrence, and offers better prognostic performance than the current grading systems.

Pancreatic ductal adenocarcinoma complete regression after preoperative chemotherapy: Surgical results in a small series

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) becomes a systemic disease from an early stage. Complete surgical resection remains the only validated and potentially curative treatment; disappointingly only 20% of patients present with a resectable tumour. Although a complete pathological regression (pCR) after the preoperative chemotherapy could intuitively lead to better outcomes and prolonged survival some reports highlighted significant rates of recurrence.

CASES PRESENTATION

We describe three cases of pCR following preoperative chemotherapy for PDAC. The first two cases received neoadjuvant mFOLFIRINOX and PAX-G scheme for borderline resectable PDAC. Recurrence appeared 9 and 12 months after surgery. Although both patients started adjuvant therapy straight after the diagnosis of recurrence, the disease rapidly progressed and led them to death 12 and 15 months after surgery. The third case was characterized by germline BRCA2 mutation. The patient presented with PDAC of the body, intrapancreatic biliary stenosis and suspected peritoneal metastasis. One year later, after first and second-line chemotherapy, she underwent explorative laparoscopy and total spleno-pancreatectomy without evidence of viable tumour cells in the surgical specimen. At six months she is recurrence-free.

CONCLUSIONS

Very few reports describe a complete pathological response following preoperative chemotherapy in pancreatic cancer. We observed three cases in the last three years with disappointing oncological results. Further investigations are needed to predict PDAC prognosis in pCR after chemotherapy.

Change in stage after neoadjuvant chemoradiation is associated with survival in patients with esophageal cancer

BACKGROUND

The aim of this study was to determine if change in stage after neoadjuvant chemoradiation (CRT) was associated with improved survival in esophageal cancer using a national database.

METHODS

Using the National Cancer Database, patients with non-metastatic, resectable esophageal cancer who received neoadjuvant CRT and surgery were identified. Comparing clinical to the pathologic stage, change in stage was classified as pathologic complete response (pCR), downstaged, same-staged, or upstaged. Univariable and multivariable Cox regression models were used to identify factors associated with survival.

RESULTS

A total of 7745 patients were identified. The median overall survival (OS) was 34.9 months. Median OS was 60.3 months if pCR, 39.1 months if downstaged, 28.3 months if same-staged, and 23.4 months if upstaged (p < 0.0001). On multivariable analysis, pCR was associated with improved OS compared to the other groups (downstaged: hazard ratio [HR]: 1.32 [95% confidence interval [CI]: 1.18-1.46]; same-staged: HR: 1.89 [95% CI: 1.68-2.13]; upstaged: HR: 2.54 [95% CI: 2.25-2.86]; all p < 0.0001).

CONCLUSIONS

In this large database study, change in stage after neoadjuvant CRT was strongly associated with survival for patients with non-metastatic, resectable esophageal cancer. There was a significant stepwise decline in survival, in descending order of pCR, downstaged tumor, same-staged tumor, and upstaged tumor.

Pathologic tumor response to neoadjuvant therapy in resected pancreatic cancer: does it affect prognosis?

Neoadjuvant therapy (NAT) + surgical resection for pancreatic cancer (PC) has gained consensus in recent years. Pathological response (PR) is generally assessed according to the College of American Pathologists grading system, ranging from 0 (complete response) to 3 (no response). The aim of our study is to evaluate the PR in a series of resections for PC after NAT and its prognostic implication. 112 patients undergone NAT and resection for PC between 2011 and 2020 were retrospectively evaluated. PR was 0/1, 2 and 3 in 18 (15%), 79 (61%) and 29 (24%) cases, respectively. Chemotherapy regimens different from FOLFIRINOX and gemcitabine + nab-paclitaxel (OR 11.61 (2.53-53.36), p = 0.002) and lymphovascular invasion (OR 11.28 (1.89-67.23), p = 0.008) were associated to PR-3. Median follow-up was 25.8 (3.6-130.5) months. For PR-0/1, PR-2 and PR-3, median DFS was 45.8, 11.5, 4.6 months (p < 0.0001), respectively, while median OS was not reached, 27.1 and 17.5 months (p = 0.0006), respectively. At univariate analysis, PR-0/1 was significantly associated to better DFS and OS (HR 0.33 (0.17-0.67), p = 0.002; HR 0.20 (0.07-0.54), p = 0.002, respectively). At multivariate analysis, pancreaticoduodenectomy (HR 0.50 (0.30-0.84), p = 0.009), LNR (HR 27.14 (1.21-608.9), p = 0.038) and lymphovascular invasion (HR 1.99 (1.06-3.76), p = 0.033) were independently associated to DFS; pre-treatment CA 19.9 value (HR 1.00 (1.00-1.00), p = 0.025), post-treatment resectability status (HR 0.51 (0.28-0.95), p = 0.035), pancreaticoduodenectomy (HR 0.56 (0.32-0.99), p = 0.050), severe morbidity (2.99 (1.22-7.55), p = 0.017), LNR (HR 56.8 (2.08-1548.3), p = 0.017), lymphovascular invasion (HR 2.18 (1.08-4.37), p = 0.029) were independently associated to OS. PR did not reach statistical significance at multivariate analysis. A favorable PR is observed only in a limited number of cases. The prognostic role of PR, despite being promising, remains unclear and further multicentric studies are needed.

Targeted therapy for pancreatic ductal adenocarcinoma: Mechanisms and clinical study

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive and lethal malignancy with a high rate of recurrence and a dismal 5-year survival rate. Contributing to the poor prognosis of PDAC is the lack of early detection, a complex network of signaling pathways and molecular mechanisms, a dense and desmoplastic stroma, and an immunosuppressive tumor microenvironment. A recent shift toward a neoadjuvant approach to treating PDAC has been sparked by the numerous benefits neoadjuvant therapy (NAT) has to offer compared with upfront surgery. However, certain aspects of NAT against PDAC, including the optimal regimen, the use of radiotherapy, and the selection of patients that would benefit from NAT, have yet to be fully elucidated. This review describes the major signaling pathways and molecular mechanisms involved in PDAC initiation and progression in addition to the immunosuppressive tumor microenvironment of PDAC. We then review current guidelines, ongoing research, and future research directions on the use of NAT based on randomized clinical trials and other studies. Finally, the current use of and research regarding targeted therapy for PDAC are examined. This review bridges the molecular understanding of PDAC with its clinical significance, development of novel therapies, and shifting directions in treatment paradigm.

The Histopathology of Neoadjuvant-Treated (NAT) Pancreatic Ductal Adenocarcinoma

Examination of pancreatic ductal adenocarcinoma after NAT with the intent of diagnosis and outcome prediction remains a challenging task. The lack of a uniform approach to macroscopically assess these cases along with variations in sampling adds to the complexity. Several TRG systems have been proposed to correlate with an overall survival. In clinical practice, most of these TRG schemes have shown low level of interobserver agreement arguing for a need of larger studies and more innovative ways to assess outcome in this population.

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.

ITGA2 overexpression inhibits DNA repair and confers sensitivity to radiotherapies in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a dismal disease with a 5-year survival rate of less than 10%, despite the recent advances in chemoradiotherapy. The sensitivity of the PDAC patients to chemoradiotherapy varies widely, especially to radiotherapy, suggesting the need for more elucidation of the underlying mechanisms. In this study, a novel function of the nuclear ITGA2, the alpha subunit of transmembrane collagen receptor integrin alpha-2/beta-1, regulating the DNA damage response (DDR), was identified. First, analyzing The Cancer Genome Atlas (TCGA) PDAC data set indicated that the expression status of ITGA2 was negatively correlated with the genome stability parameters. The study further demonstrated that ITGA2 specially inhibited the activity of the non-homologous end joining (NHEJ) pathway and conferred the sensitivity to radiotherapy in PDAC by restraining the recruitment of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) to Ku70/80 heterodimer during DDR. Considering the overexpression of ITGA2 and its associated with the poor prognosis of PDAC patients, this study suggested that the ITGA2 expression status could be used as an indicator for radiotherapy and DNA damage reagents, and the radiotherapy in combination with the overexpression of ITGA2 might be a viable treatment strategy for the PDAC patients.

Critical issues in pathologic evaluation of pancreatic ductal adenocarcinoma resected after neoadjuvant treatment: a narrative review

BACKGROUND AND OBJECTIVE

Preoperative neoadjuvant therapy (NAT) is increasingly used in the treatment of patients with potentially resectable pancreatic ductal adenocarcinoma (PDAC). Because NAT often induces heterogeneous tumor response and extensive fibrosis both in tumor and adjacent pancreatic tissue, pathologic assessment of posttherapy pancreatectomy specimens is challenging. A limited number of studies examined the optimal grossing and sampling methods, tumor response grading (TRG), and the prognostic value of posttherapy tumor (ypT) and lymph node (ypN) stages of treated PDAC patients. In this review, we will provide an overview of the current status and critical issues in pathologic evaluation of PDAC resected after NAT.

METHODS

In PubMed, Google Scholar and Web of Science, we reviewed existing English literature (published up to December 2021) highlighting the most recent ones using electronic databases and authors' experience to outline the challenging aspects and new perspectives on pathologic assessment of the treated PDAC.

KEY CONTENT AND FINDINGS

The recent recommendations from the Pancreatobiliary Pathology Society (PBPS) provide the much-needed guidelines for systematic and standardized pathologic evaluation and reporting of treated PDAC for optimal patient care. For treated PDAC, tumor size measured by gross and radiology is not reliable. Histologic validation of tumor size on consecutive mapping sections is recommended for accurate ypT stage. A tumor size of 1.0 cm seems to be a better cutoff for ypT2 for treated PDACs. The published data suggested that the MD Anderson Cancer Center (MDA) TRG system is easy to use, has a better interobserver agreement and better correlation with patient prognosis compared to the College of American Pathologists (CAP) and Evans grading systems and may be used as an alternative TRG system for the CAP cancer protocol.

CONCLUSIONS

Systemic and standardized grossing and sampling are essential for accurate pathologic evaluation and reporting for optimal care of PDAC patients who received NAT. Future studies on optimal sampling and integration of histopathology with artificial intelligence (AI), molecular and immunohistochemical markers are needed for better and personalized care of treated PDAC patients.

Pathologic Examination of Pancreatic Specimens Resected for Treated Pancreatic Ductal Adenocarcinoma: Recommendations From the Pancreatobiliary Pathology Society

Currently, there are no internationally accepted consensus guidelines for pathologic evaluation of posttherapy pancreatectomy specimens. The Neoadjuvant Therapy Working Group of Pancreatobiliary Pathology Society was formed in 2018 to review grossing protocols, literature, and major issues and to develop recommendations for pathologic evaluation of posttherapy pancreatectomy specimens. The working group generated the following recommendations: (1) Systematic and standardized grossing and sampling protocols should be adopted for pancreatectomy specimens for treated pancreatic ductal adenocarcinoma (PDAC). (2) Consecutive mapping sections along the largest gross tumor dimension are recommended to validate tumor size by histology as required by the College of American Pathologists (CAP) cancer protocol. (3) Tumor size of treated PDACs should be measured microscopically as the largest dimension of tumor outer limits that is bound by viable tumor cells, including intervening stroma. (4) The MD Anderson grading system for tumor response has a better correlation with prognosis and better interobserver concordance among pathologists than does the CAP system. (5) A case should not be classified as a complete response unless the entire pancreas, peripancreatic tissues, ampulla of Vater, common bile duct, and duodenum adjacent to the pancreas are submitted for microscopic examination. (6) Future studies on tumor response of lymph node metastases, molecular and/or immunohistochemical markers, as well as application of artificial intelligence in grading tumor response of treated PDAC are needed. In summary, systematic, standardized pathologic evaluation, accurate tumor size measurement, and reproducible tumor response grading to neoadjuvant therapy are needed for optimal patient care. The criteria and discussions provided here may provide guidance towards these goals.

Pathological treatment response has different prognostic implications for pancreatic cancer patients treated with neoadjuvant chemotherapy or chemoradiotherapy

BACKGROUND

Pathological treatment effect of resected pancreatic adenocarcinoma after neoadjuvant therapy has prognostic implications. The impact for patients who received chemotherapy alone or chemoradiotherapy is not well defined.

METHODS

Patients with localized pancreatic adenocarcinoma who had pancreatectomy after neoadjuvant therapy at 3 centers from 2011 to 2017 were retrospectively analyzed. The chemotherapy and chemoradiotherapy groups were evaluated separately.

RESULTS

Of 525 patients, 148 received neoadjuvant chemotherapy and 377 received chemoradiotherapy. The chemoradiotherapy group had a better treatment effect (score 0: 10%, score 1: 30%, score 2: 42%, and score 3: 18%) than the chemotherapy group (score 0: 2%, score 1: 8%, score 2: 35%, and score 3: 55%) (P < .001). Median overall survival was similar between the 2 groups (25.8 vs 26.4 months). Median overall survival for score 0/1, 2, or 3 was 72.2, 38.5, and 20.0 months in the chemotherapy group and 37.9, 24.5, and 19.0 months in the chemoradiotherapy group. Score 2 in the chemotherapy group was associated with better overall survival compared to score 3 (adjusted hazard ratio: 0.49, P = .005), whereas only combined score 0/1 reached significance over score 2 for the chemoradiotherapy group (hazard ratio: 0.63, P = .006).

CONCLUSION

The prognostic significance of pathological treatment effect for localized pancreatic adenocarcinoma differs for patients receiving neoadjuvant chemotherapy or neoadjuvant chemoradiotherapy.

Neoadjuvant Chemotherapy Switch in Borderline Resectable/Locally Advanced Pancreatic Cancer

BACKGROUND

Neoadjuvant chemotherapy (NAC) is an integral part of preoperative treatment for patients with borderline resectable/locally advanced (BR/LA) pancreatic ductal adenocarcinoma (PDAC). The identification of a chemotherapeutic regimen that is both effective and tolerable is critical for NAC to be of oncologic benefit. After initial first-line (FL) NAC, some patients have lack of response or therapeutic toxicities precluding further treatment with the same regimen; optimal decision making regarding this patient population is unclear. Chemotherapy switch (CS) may allow for a larger proportion of patients to undergo curative-intent resection after NAC.

METHODS

We reviewed our surgical database for patients undergoing combinatorial NAC for BR/LA PDAC. Variant histologic exocrine carcinomas, intraductal papillary mucinous neoplasm-associated PDAC, and patients without research consent were excluded.

RESULTS

Overall, 468 patients with BR/LA PDAC receiving FL chemotherapy were reviewed, of whom 70% (329/468) continued with FL chemotherapy followed by surgical resection. The remaining 30% (139/468) underwent CS, with 72% (100/139) of CS patients going on to curative-intent surgical resection. Recurrence-free survival (RFS) and overall survival (OS) were not significantly different between the resected FL and CS cohorts (30.0 vs. 19.1 months, p = 0.13, and 41.4 vs. 36.4 months, p = 0.94, respectively) and OS was significantly worse in those undergoing CS without subsequent resection (19 months, p < 0.0001). On multivariable analysis, carbohydrate antigen (CA) 19-9 and pathologic treatment responses were predictors of RFS and OS.

CONCLUSION

CS in patients undergoing NAC for BR/LA pancreatic cancer does not incur oncologic detriment. The incorporation of CS into NAC treatment sequencing may allow a greater proportion of patients to proceed to curative-intent surgery.

Baseline CT-based Radiomic Features Aid Prediction of Nodal Positivity after Neoadjuvant Therapy in Pancreatic Cancer

Purpose To study the association between CT-derived textural features of pancreatic cancer and patient outcome. Materials and Methods This retrospective study evaluated 54 patients (median age, 62 years [range, 40-88 years]; 32 men) with pancreatic cancer who underwent chemoradiation followed by surgical resection and lymph node dissection from May 2012 to June 2016. Three-dimensional segmentation of the pancreatic tumor was performed on baseline dual-energy CT images: 70-keV pancreatic parenchymal phase (PPP) images and iodine material density images. Then, 15 and 19 radiomic features were extracted from each phase, respectively. Logistic regression with elastic net regularization was used to select textural features associated with outcome, and receiver operating characteristic analysis evaluated feature performance. Survival curves were generated using the Kaplan-Meier method. Results The feature of integral total (∫ T), representing the mean intensity in Hounsfield units times the contour volume in milliliters of PPP imaging (hereafter, "∫ T (HU·mL) (PPP)"), is inversely associated with posttherapy pathologic lymph node (ypN) category. A threshold ∫ T (HU·mL) (PPP) less than 507.85 predicted ypN1-2 classification with 96% sensitivity, 34% specificity, and area under the curve of 0.61. Patients with an ∫ T (HU·mL) (PPP) of less than 507.85 had decreased overall survival (median, 2.8 years) compared with patients with an ∫ T (HU·mL) (PPP) of 507.85 or greater (one event at 3.4 years) (P = .006). Patients with an ∫ T (HU·mL) (PPP) of less than 507.85 had decreased progression-free survival (median, 1.5 years) compared with patients with an ∫ T (HU·mL) (PPP) of 507.85 or greater (median, 2.7 years) (P = .001). Conclusion A CT-based radiomic signature may help predict ypN category in patients with pancreatic cancer. Keywords: CT-Dual Energy, Abdomen/GI, Pancreas, Tumor Response, Outcomes Analysis © RSNA, 2022 Supplemental material is available for this article.

Neoadjuvant Treatment for Resectable and Borderline Resectable Pancreatic Cancer: Chemotherapy or Chemoradiotherapy?

Worldwide, there is a shifting paradigm from immediate surgery with adjuvant treatment to a neoadjuvant approach for patients with resectable or borderline resectable pancreatic cancer (RPC or BRPC). Comparison of neoadjuvant and adjuvant studies is extremely difficult because of a great difference in patient selection. The evidence from randomized studies shows that overall survival by intention-to-treat improves after neoadjuvant gemcitabine-based chemoradiotherapy or chemotherapy (various regimens), as compared to immediate surgery followed by adjuvant chemotherapy. Radiotherapy appears to play an important role in mediating locoregional effects. Yet, since more effective chemotherapy regimens are currently available, in particular FOLFIRINOX and Gemcitabine/Nab-paclitaxel, these chemotherapy regimens should be investigated in future randomized trials combined with (stereotactic) radiotherapy to further improve outcomes of RPC and BRPC.

Neoadjuvant Therapy Is Associated with Improved Chemotherapy Delivery and Overall Survival Compared to Upfront Resection in Pancreatic Cancer without Increasing Perioperative Complications

The role of neoadjuvant chemoradiotherapy and/or chemotherapy (neoCHT) in patients with pancreatic ductal adenocarcinoma (PDAC) is poorly defined. We hypothesized that patients who underwent neoadjuvant therapy (NAT) would have improved systemic therapy delivery, as well as comparable perioperative complications, compared to patients undergoing upfront resection. This is an IRB-approved retrospective study of potentially resectable PDAC patients treated within an academic quaternary referral center between 2011 and 2018. Data were abstracted from the electronic medical record using an institutional cancer registry and the National Surgical Quality Improvement Program. Three hundred and fourteen patients were eligible for analysis and eighty-one patients received NAT. The median overall survival (OS) was significantly improved in patients who received NAT (28.6 vs. 20.1 months, p = 0.014). Patients receiving neoCHT had an overall increased mean duration of systemic therapy (p < 0.001), and the median OS improved with each month of chemotherapy delivered (HR = 0.81 per month CHT, 95% CI (0.76-0.86), p < 0.001). NAT was not associated with increases in early severe post-operative complications (p = 0.47), late leaks (p = 0.23), or 30-90 day readmissions (p = 0.084). Our results show improved OS in patients who received NAT, driven largely by improved chemotherapy delivery, without an apparent increase in early or late perioperative complications compared to patients undergoing upfront resection.

BRCA 1/2 Germline Mutation Predicts the Treatment Response of FOLFIRINOX with Pancreatic Ductal Adenocarcinoma in Korean Patients

We evaluated the proportion of BRCA 1/2 germline mutations in Korean patients with sporadic pancreatic ductal adenocarcinoma (PDAC) and its effect on the chemotherapeutic response of FOLFIRINOX. This retrospective study included patients who were treated at two tertiary hospitals between 2012 and 2020, were pathologically confirmed to have PDAC, and had undergone targeted next-generation sequencing-based germline genetic testing. Sixty-six patients were included in the study (24 men; median age 57.5 years). In the germline test, BRCA 1/2 pathogenic mutations were found in nine patients (9/66, 13%, BRCA 1, n = 3; BRCA 2, n = 5; and BRCA 1/2, n = 1). There was no significant difference in the baseline characteristics according to BRCA mutation positivity. Among patients who underwent FOLFIRINOX chemotherapy, patients with a BRCA 1/2 mutation showed a higher overall response rate than those without a BRCA 1/2 mutation (71.4% vs. 13.9%, p = 0.004). Patients with a germline BRCA 1/2 mutation showed longer progression-free survival than those without a BRCA 1/2 mutation, without a significant time difference (18 months vs. 10 months, p = 0.297). Patients with a BRCA 1/2 mutation in the germline blood test had a higher response rate to FOLFIRINOX chemotherapy in PDAC. The high proportion of BRCA 1/2 germline mutations and response rate supports the need for germline testing in order to predict better treatment response.

Neoadjuvant Radiotherapy is Associated With Improved Pathologic Outcomes and Survival in Resected Stage II-III Pancreatic Adenocarcinoma Treated With Multiagent Neoadjuvant Chemotherapy in the Modern Era

BACKGROUND

Neoadjuvant chemotherapy (CT) is being utilized more frequently in patients diagnosed with localized pancreatic cancer. The role of additional neoadjuvant radiotherapy (RT) remains undefined. We explored outcomes associated with neoadjuvant RT in the modern era.

METHODS

The National Cancer Database (2010-2017) was queried for patients with clinical stage II-III pancreatic adenocarcinoma who received neoadjuvant multiagent systemic CT +/- RT. Demographics, pathologic outcomes, postoperative outcomes, and overall survival were compared.

RESULTS

A total of 5245 patients were included, of whom 3123 received CT and 1941 received CT + RT. Use of RT decreased over the 8-year study period. On multivariable analysis, treatment at academic facilities (odds ratio (OR) = 1.52, P < .001) and clinical T4 tumors (OR = 1.68, P < .001) were independently associated with receipt of RT. Patients treated with CT + RT had a higher frequency of ypT0-T2 tumors (35.8% vs. 22.7%) and a lower rate of ypT3-T4 tumors (57.3% vs. 72.8%; P < .001), lower rate of node-positive disease (36.6% vs. 59.8%, P < .001), and margin-positive resections (13.8% vs. 20.2%, P < .001), but slightly higher 90-day postoperative mortality (4.9% vs. 3.6%, P = .04). Neoadjuvant chemotherapy+ RT was associated with longer overall survival (32.7 vs. 29.8 months, P = .008), and remained independently associated with survival on multivariable analysis (HR = .85, P < .001).

DISCUSSION

In patients with stage II-III pancreatic adenocarcinoma, the addition of neoadjuvant RT to multiagent neoadjuvant CT may be associated with increased rates of node-negative and margin-negative resection, as well as improved overall survival.

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

BACKGROUND

The role of neoadjuvant stereotactic body radiation therapy (SBRT) in patients with borderline resectable pancreas cancer (BRPC) and locally advanced pancreas cancer (LAPC) remains controversial.

METHODS

We retrospectively evaluated BRPC and LAPC patients treated at our institution who underwent 2-3 months of chemotherapy followed by SBRT to a dose of 30-33 Gy. Overall survival (OS) and recurrence-free survival (RFS) were estimated and compared by Kaplan-Meier and log-rank methods.

RESULTS

We identified 103 (85 BRPC and 18 LAPC) patients treated per our neoadjuvant paradigm between 2011 and 2018, with resectability based on NCCN definitions. Median follow up was 25 months. Of patients completing neoadjuvant therapy, 73 (71%) underwent definitive resection. Seventy-one (97%) patients with definitively resected tumors had R0 resection and 5 (7%) had a complete pathologic response CR to neoadjuvant therapy. The median overall survival (OS) of the cohort was 24 months. Those with a complete or marked pathologic response had significantly better OS than those with a moderate response (41 vs 24 months, p < 0.02) and patients unable to undergo definitive surgery (17 months, p < 0.0003). Six resected patients experienced grade ≥3 surgical complications.

CONCLUSIONS

Neoadjuvant chemotherapy and SBRT are associated with promising pathologic response rates and R0 resection rates, with acceptable perioperative morbidity.

Pathology of Treated Pancreatic Ductal Adenocarcinoma and Its Clinical Implications

CONTEXT.—

Preoperative neoadjuvant therapy has been increasingly used to treat patients with potentially resectable pancreatic ductal adenocarcinoma (PDAC). Neoadjuvant therapy often induces extensive fibrosis in tumor, adjacent pancreatic parenchyma, and peripancreatic tissue. Histopathologic evaluations and histologic tumor response grading (HTRG) of posttherapy pancreatectomy specimens are very difficult and challenging. Studies on prognostic significance of posttherapy pathologic staging, optimal system for HTRG, and other pathologic parameters in treated PDAC patients are limited.

OBJECTIVE.—

This review is to provide a timely update of the prognostic values of posttherapy pathologic staging, HTRG, and other pathologic parameters in PDAC patients who received neoadjuvant therapy and pancreas resection.

DATA SOURCES.—

Systemic review of major studies on pathologic evaluation and its clinicopathologic implications in treated PDAC patients.

CONCLUSIONS.—

Systemic pathologic examination, histologic tumor regression grading, pathologic evaluation of the margins, tumor involvement of superior mesenteric vein/portal vein, accurate pathologic staging, and reporting of posttherapy pancreatectomy specimens provide highly valuable prognostic information for postoperative patient care. Our findings suggest for the first time that tumor size of 1.0 cm, instead of 2.0 cm, is a better cutoff for ypT2 in PDAC patients. The newly proposed 3-tier MD Anderson HTRG system not only has proved to be an independent prognostic marker for PDAC patients who received neoadjuvant therapy and pancreatectomy, but also improves interobserver agreement among pathologists in evaluation of tumor response. This grading system should be considered in future editions of the College of American Pathologists protocol for PDAC.

Four-Tier Pathologic Tumor Regression Grading System Predicts the Clinical Outcome in Patients Who Undergo Surgical Resection for Locally Advanced Pancreatic Cancer after Neoadjuvant Chemotherapy

Background/Aims

Neoadjuvant chemotherapy is increasingly utilized in patients with borderline or locally advanced pancreatic cancer (LAPC). However, the pathologic evaluation of tumor regression is not routinely performed or well established. We aimed to evaluate the prognostic value of three tumor regression grading systems frequently used in LAPC and to determine the correlation between pathologic and clinical response.

Methods

We included a total of 38 patients with LAPC who were treated with neoadjuvant chemotherapy and subsequent resection. Pathologic tumor regression was graded based on the College of American Pathologists (CAP), Evans, and MD Anderson grading systems.

Results

One out of 38 patients (2.6%) achieved a pathologic complete response. Unlike other grading systems (Evans, p=0.063; MD Anderson, p=0.110), the CAP grading system was a significant prognostic factor for overall survival (p=0.043). Pathologic N stage (p=0.023), margin status (p=0.044), and radiologic response (p=0.016) correlated with overall survival. In the multivariate analysis, CAP 3 was an independent predictor of shorter overall survival (p=0.026). The CAP grading system correlated with the radiologic response (p=0.007) but not the carbohydrate antigen 19-9 level (p=0.333).

Conclusions

The four-tier CAP pathologic tumor regression grading system predicted the clinical outcome in LAPC patients who underwent resection after neoadjuvant chemotherapy. Therefore, a more comprehensive pathologic evaluation is warranted in these patients.

Radiographic and Serologic Predictors of Pathologic Major Response to Preoperative Therapy for Pancreatic Cancer

OBJECTIVE

We sought to identify potential radiologic and serologic markers of pancreatic tumor response to therapy, using pathologic major response (pMR) as the objective endpoint.

BACKGROUND

We previously demonstrated that a pMR to preoperative therapy, defined as detection of <5% viable cancer cells in the surgical specimen on histopathological analysis, is an important prognostic factor for patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

Pretreatment and posttreatment computed tomography scans of consecutive patients who received preoperative chemotherapy and/or (chemo)radiation before pancreatectomy for PDAC between January 2010 and December 2018 were rereviewed. Response per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, other radiographic changes in tumor size and anatomic extent, and posttreatment CA 19-9 levels were compared between patients who did and did not have a pMR on final histopathologic analysis of their surgical specimens.

RESULTS

A total of 290 patients with localized PDAC underwent pancreatectomy between 2010 and 2018 after receiving preoperative chemotherapy (n = 36; 12%), (chemo)radiation (n = 87; 30%), or both (n = 167; 58%). Among them, 28 (10%) experienced pMR, including 9 (3.1%) who experienced pathologic complete response. On multivariable logistic regression, low posttreatment CA 19-9 level, RECIST partial response, and reduction in tumor volume were confirmed to be independently associated with pMR (P < 0.01).

CONCLUSIONS

We identified serologic and radiographic indicators of pMR that could help inform the delivery of preoperative therapy to patients with PDAC.

Pathological complete response after neoadjuvant therapy for pancreatic ductal adenocarcinoma does not equal cure

BACKGROUND

There is a scarcity of data about patients with pancreatic ductal adenocarcinoma (PDAC) who received neoadjuvant therapy before radical resection and achieved a pathological complete response (pCR). The aim of this study was to describe the recurrence and survival in this subset of patients.

METHODS

The Embase, Web of Science and PubMed databases were systematically searched for eligible studies published between January 2000 and August 2020. Clinicopathological data of individual patients with pCR after neoadjuvant therapy for PDAC were extracted, pooled and analysed.

RESULTS

A total of 87 patients were subject to analysis. The majority of patients were female (61.5%) with a median age of 64 (range 43-75) years. Among reported, 41.9% of patients received gemcitabine-based neoadjuvant chemotherapy, 33.7% received FOLFIRINOX (5-fluorouracil, oxaliplatin, irinotecan and leucovorin)-based regimen and 24.4% received fluoropyrimidine drugs-based regimen. Preoperative radiation was administered to 78.8% of the patients. Twenty-nine (33.3%) patients developed disease recurrence during a median follow-up period of 22.4 (range 2-194) months. The median, 1-, 3- and 5-year overall survival rates were 105 months, 93.6%, 70.3% and 70.3%, respectively.

CONCLUSION

Despite the excellent long-term outcomes, a pCR does not equal cure because this cohort of patients still has a significant risk of recurrence.

Factors Predicting Response, Perioperative Outcomes, and Survival Following Total Neoadjuvant Therapy for Borderline/Locally Advanced Pancreatic Cancer

OBJECTIVE

To identify predictive factors associated with operative morbidity, mortality, and survival outcomes in patients with borderline resectable (BR) or locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC) undergoing total neoadjuvant therapy (TNT).

BACKGROUND

The optimal preoperative treatment sequencing for BR/LA PDA is unknown. TNT, or systemic chemotherapy followed by chemoradiation (CRT), addresses both occult metastases and positive margin risks and thus is a potentially optimal strategy; however, factors predictive of perioperative and survival outcomes are currently undefined.

METHODS

We reviewed our experience in BR/LA patients undergoing resection from 2010 to 2017 following TNT assessing operative morbidity, mortality, and survival in order to define outcome predictors and response endpoints.

RESULTS

One hundred ninety-four patients underwent resection after TNT, including 123 (63%) BR and 71 (37%) LA PDAC. FOLFIRINOX or gemcitabine along with nab-paclitaxel were used in 165 (85%) and 65 (34%) patients, with 36 (19%) requiring chemotherapeutic switch before long-course CRT and subsequent resection. Radiologic anatomical downstaging was uncommon (28%). En bloc venous and/or arterial resection was required in 125 (65%) patients with 94% of patients achieving R0 margins. The 90-day major morbidity and mortality was 36% and 6.7%, respectively. Excluding operative mortalities, the median, 1-year, 2-year, and 3-year recurrence-free survival (RFS) [overall survival (OS)] rates were 23.5 (58.8) months, 65 (96)%, 48 (78)%, and 32 (62)%, respectively. Radiologic downstaging, vascular resection, and chemotherapy regimen/switch were not associated with survival. Only 3 factors independently associated with prolonged survival, including extended duration (≥6 cycles) chemotherapy, optimal post-chemotherapy CA19-9 response, and major pathologic response. Patients achieving all 3 factors had superior survival outcomes with a survival detriment for each failing factor. In a subset of patients with interval metabolic (PET) imaging after initial chemotherapy, complete metabolic response highly correlated with major pathologic response.

CONCLUSION

Our TNT experience in resected BR/LA PDAC revealed high negative margin rates despite low radiologic downstaging. Extended duration chemotherapy with associated biochemical and pathologic responses highly predicted postoperative survival. Potential modifications of initial chemotherapy treatment include extending cycle duration to normalize CA19-9 or achieve complete metabolic response, or consideration of chemotherapeutic switch in order to achieve these factors may improve survival before moving forward with CRT and subsequent resection.

Reshaping preoperative treatment of pancreatic cancer in the era of precision medicine

This review summarises the recent evidence on preoperative therapeutic strategies in pancreatic cancer and discusses the rationale for an imminent need for a personalised therapeutic approach in non-metastatic disease. The molecular diversity of pancreatic cancer and its influence on prognosis and treatment response, combined with the failure of 'all-comer' treatments to significantly impact on patient outcomes, requires a paradigm shift towards a genomic-driven approach. This is particularly important in the preoperative, potentially curable setting, where a personalised treatment allocation has the substantial potential to reduce pancreatic cancer mortality.

Meta-analysis of FOLFIRINOX-based neoadjuvant therapy for locally advanced pancreatic cancer

Currently, the combination of 5-fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX) is the standard therapy for metastatic pancreatic cancer. In recent years, FOLFIRINOX-based neoadjuvant therapy for locally advanced pancreatic cancer (LAPC) has been gaining an increasing amount of attention, owing to its ability to reduce disease stage and transform LAPC to borderline resectable or even resectable pancreatic cancer. Accordingly, we aimed to evaluate the efficacy of first-line FOLFIRINOX chemotherapy in patients with LAPC.We searched PubMed, Embase, and Cochrane Library from the time of establishment till January 1, 2020 and included studies focusing on LAPC patients who received FOLFIRINOX as first-line neoadjuvant treatment. The primary outcomes were: resection rate and radical (R0) resection rate while the secondary outcomes were: objective response rate, overall survival, progression-free survival, and rate of grade 3 to 4 adverse events. The meta package for R 3.6.2 was used for heterogeneity and publication bias testing.Twenty-one studies, including 653 patients with LAPC, were selected. After treatment with FOLFIRINOX, the resection rate was 26% (95% confidence interval [CI] = 20%-32%, I2 = 61%) and R0 resection rate was 88% (95% CI = 78%-95%, I2 = 62%). The response rate was 34% (95% CI = 25%-43%, I2 = 56%). The median overall survival and progression-free survival durations ranged from 10.0 to 32.7 months and 3.0 to 25.3 months, respectively. The observed grade 3 to 4 adverse events were neutropenia (20.0 per 100 patients, 95% CI = 14%-27%, I2 = 75%), febrile neutropenia (7.0 per 100 patients, 95% CI = 5%-9%, I2 = 42%), thrombocytopenia (6.0 per 100 patients, 95% CI = 5%-8%, I2 = 27%), nausea/vomiting (7.0 per 100 patients, 95% CI = 7%-12%, I2 = 76%), diarrhea (10.0 per 100 patients, 95% CI = 8%-12%, I2 = 38%), and fatigue (9.0 per 100 patients, 95% CI = 7%-11%, I2 = 43%).FOLFIRINOX-based neoadjuvant chemotherapy has the potential to improve the rates of resection, R0 resection, and median OS in LAPC. Our results require further validation in large, high-quality randomized controlled trials.

Neoadjuvant chemoradiation may be associated with improved pathologic response in pancreatic cancer

BACKGROUND

Neoadjuvant therapy is increasingly utilized in the management of pancreatic adenocarcinoma. The type of neoadjuvant therapy and its effect on pathologic response remains understudied.

METHODS

A retrospective review was performed on patients who underwent neoadjuvant therapy followed by pancreatectomy. Multivariable regressions were used to determine associations between neoadjuvant therapy regimens and pathologic response.

RESULTS

Seventy-five patients with pathologic responses available for review received FOLFIRINOX (61%) or gemcitabine with nab-paclitaxel (39%). Demographics, histologic differentiation, and utilization of chemoradiation were similar between the groups. Multivariable logistic regression demonstrated that chemoradiation was associated with an increased likelihood of a complete or near-complete pathologic response and a decreased rate of lymphovascular invasion and lymph node positivity. Neither chemotherapy regimen nor number of cycles administered were associated with pathologic response.

CONCLUSIONS

Neoadjuvant chemoradiation may be associated with complete or near-complete pathologic response regardless of chemotherapy regimen in pancreatic cancer patients.

Objective assessment of tumor regression in post-neoadjuvant therapy resections for pancreatic ductal adenocarcinoma: comparison of multiple tumor regression grading systems

Neoadjuvant therapy is increasingly used to control local tumor spread and micrometastasis of pancreatic ductal adenocarcinoma (PDAC). Pathology assessments of treatment effects might predict patient outcomes after surgery. However, there are conflicting reports regarding the reproducibility and prognostic performance of commonly used tumor regression grading systems, namely College of American Pathologists (CAP) and Evans' grading system. Further, the M.D. Anderson Cancer Center group (MDA) and the Japan Pancreas Society (JPS) have introduced other grading systems, while we recently proposed a new, simple grading system based on the area of residual tumor (ART). Herein, we aimed to assess and compare the reproducibility and prognostic performance of the modified ART grading system with those of the four grading systems using a multicenter cohort. The study cohort consisted of 97 patients with PDAC who had undergone post-neoadjuvant pancreatectomy at four hospitals. All patients were treated with gemcitabine and S-1 (GS)-based chemotherapies with/without radiation. Two pathologists individually evaluated tumor regression in accordance with the CAP, Evans', JPS, MDA and ART grading systems, and interobserver concordance was compared between the five systems. The ART grading system was a 5-tiered system based on a number of 40× microscopic fields equivalent to the surface area of the largest ART. Furthermore, the final grades, which were either the concordant grades of the two observers or the majority grades, including those given by the third observer, were correlated with patient outcomes in each system. The interobserver concordance (kappa value) for Evans', CAP, MDA, JPS and ART grading systems were 0.34, 0.50, 0.65, 0.33, and 0.60, respectively. Univariate analysis showed that higher ART grades were significantly associated with shorter overall survival (p = 0.001) and recurrence-free survival (p = 0.005), while the other grading systems did not show significant association with patient outcomes. The present study revealed that the ART grading system that was designed to be simple and more objective has achieved high concordance and showed a prognostic value; thus it may be most practical for assessing tumor regression in post-neoadjuvant resections for PDAC.

Is Complete Pathologic Response in Pancreatic Cancer Overestimated? A Systematic Review of Prospective Studies

BACKGROUND

In literature, percentages of pathologic complete response (pCR) in patients presenting with resectable (RES), borderline resectable (BLR) or locally advanced (LA) pancreatic cancer (PaC) after neoadjuvant treatment (NADT) are variable, ranging 0-33%. Those data come mostly from retrospective reviews of single centres. The objective of this systematic review is to assess the incidence of pCR.

METHODS

Following the criteria of the PRISMA statement, a literature search was conducted looking for prospective papers focusing on neoadjuvant treatment in PaC. Retrospective papers, other than ductal carcinoma histologies and trials including metastatic patients, were excluded from the present review. Data extraction was carried out by 3 independent investigators. Meta-analysis was performed with ProMeta3 Software (Internovi, 2015). PROSPERO registry: CRD42018095641.

RESULTS

The literature search of Embase, Cochrane and Medline with the terms "neoadjuvant OR preoperative", "pancreatic OR pancreas" and "cancer OR adenocarcinoma OR tumor" led to the identification of 3128 papers. We restricted the search to humans, last 10 years and English language articles resulting in 1158 eligible articles to review. Extended paper revision led to the inclusion of 27 papers. Complete pathologic response ranged 0-11.11%, at the meta-analysis 4% (95% CI 3-5%), in prospective studies 0-9.09% and in prospective databases 1.63-11.11%.

CONCLUSIONS

Pathologic complete response in pancreatic cancer is actually infrequent: high-quality studies provide a more reliable picture of neoadjuvant effects, high rates of pCR are reported in selected retrospective studies but it is overestimated.

Multiparametric MRI for prediction of treatment response to neoadjuvant FOLFIRINOX therapy in borderline resectable or locally advanced pancreatic cancer

OBJECTIVES

To identify multiparametric MRI biomarkers to predict the tumor response to neoadjuvant FOLFIRINOX therapy in patients with borderline resectable (BR) or locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC).

METHODS

From May 2016 to March 2018, adult patients with BR or LA PDAC were prospectively enrolled in this study. They received eight cycles of FOLFIRINOX therapy and underwent multiparametric MRI twice (at baseline and after the second cycle). MRI evaluations included dynamic contrast-enhanced MRI, intravoxel incoherent motion diffusion-weighted imaging, and assessment of T2* relaxivity (R2*) and the change in T1 relaxivity (ΔR1, equilibrium phase R1 minus non-enhanced R1) of the tumors. Factors to predict the responders determined by the best overall response during FOLFIRINOX therapy and those to predict progression-free survival (PFS) and overall survival (OS) were evaluated using multivariable logistic regression and the Cox proportional hazard model.

RESULTS

Forty-one patients (mean age, 60.3 years ± 9.3; 24 men) were included. Among the clinical and MRI factors, the baseline ΔR1 (adjusted odds ratio, 31.07; p = 0.008) was the only independent predictor for tumor response. The baseline ΔR1 was also an independent predictor for PFS (adjusted hazard ratio, 0.40; p = 0.033) along with R0 resection. The use of a cutoff ΔR1 value of ≥ 1.31 s^-1 enabled prognostic stratification (median PFS, 16.0 months vs.10.0 months; p = 0.029; median OS, 34.9 months vs. 16.6 months; p = 0 .023, respectively).

CONCLUSIONS

The baseline tumor ΔR1 value may be useful to predict tumor response and survival in patients with BR or LA PDAC receiving FOLFIRINOX neoadjuvant therapy.

KEY POINTS

• Baseline ΔR1 was an independent predictor for tumor response (adjusted odds ratio, 31.07; p = 0.008) and progression-free survival (adjusted hazard ratio, 0.40; p = 0.033) in patients with borderline resectable or locally advanced pancreatic ductal adenocarcinoma receiving neoadjuvant FOLFIRINOX therapy. • The criterion of baseline ΔR1 value ≥ 1.31 s^-1 allowed for the prediction of favorable tumor response and survival outcome after neoadjuvant FOLFIRINOX therapy.

Tumor marker recovery rather than major pathological response is a preferable prognostic factor in patients with pancreatic ductal adenocarcinoma with preoperative therapy

BACKGROUND/PURPOSE

A pathological response of the primary tumor by preoperative therapy is a prognostic factor in various malignancies, and several histologic grading systems have been proposed for pancreatic ductal adenocarcinoma (PDAC). However, the prognostic value remains unclear. We explored the clinical implication of a major pathological response following preoperative therapy in patients with PDAC.

METHODS

Of 415 patients with resected PDAC, 137 who had undergone preoperative therapy were examined. Cox proportional hazards models were used to determine the predictors of a major pathological response, and survival analyses were performed.

RESULTS

Twenty patients exhibited a major pathological response (≥90% tumor reduction). Significant associations were observed between a major pathological response and resectability (P = .001), the period of preoperative therapy (P < .001), RECIST best response (P < .001), the tumor size after preoperative therapy (P = .02), and tumor marker recovery (P < .001). Multivariate analysis of progression-free survival (PFS) revealed that both body mass index (≥20 kg/m2 ) (P = .035) and tumor marker recovery (P = .046) were independent prognostic factors. The median survival time (MST) of PFS for a ≥90% pathological response was better than that of a <90% response (P = .25); however, the MST for tumor marker recovery was significantly better than that without tumor marker recovery (P = .0054).

CONCLUSIONS

In our study, a major pathological response was not extracted as a prognostic factor. Rather, tumor marker recovery was a preferable prognostic factor in patients with PDAC who had undergone preoperative therapy.

Evaluation of Pathologic Response on Overall Survival After Neoadjuvant Therapy in Pancreatic Ductal Adenocarcinoma

OBJECTIVES

Single-institution studies have shown improved outcomes among patients with a pathologic complete response (pCR) following neoadjuvant therapy. We sought to evaluate the impact of pCR and near-complete response (nCR) on overall survival (OS) using a large national database.

METHODS

The National Cancer Database was queried for patients given a diagnosis of pancreatic cancer from 2004 to 2014. A pCR was defined as no tumor identified in the pancreas after surgical resection. An nCR was defined as a primary tumor less than 1 cm without lymph node metastases. The primary outcome was OS.

RESULTS

A total of 5364 patients underwent neoadjuvant chemotherapy and/or radiation followed by pancreatectomy. Forty-one patients (0.8%) had a pCR, 54 (1%) had an nCR, and the remaining 5266 (98.2%) had an otherwise incomplete response. Patients with pCR had a median OS of 43 months compared with 24 months for nCR and 23 months for incomplete response (P < 0.0001). Only pCR was associated with improved OS on adjusted Cox regression.

CONCLUSIONS

For patients given a diagnosis of pancreatic cancer who underwent neoadjuvant treatment and surgical resection, achieving a pCR was associated with improved OS compared with those with residual tumor. An association between nCR and improved survival was not observed.

The Impact of Prolonged Chemotherapy to Surgery Interval and Neoadjuvant Radiotherapy on Pathological Complete Response and Overall Survival in Pancreatic Cancer Patients

Background:

We aimed to study the impact of neoadjuvant chemotherapy to surgery (NCT-S) interval and neoadjuvant radiotherapy (NRT) on pathological complete response (pCR) and overall survival (OS) in pancreatic cancer (pancreatic ductal adenocarcinoma [PDAC]).

Methods:

National Cancer Data Base (NCDB)–pancreatectomy patients who underwent NCT/NRT were included. The NCT-S interval was divided into time quintiles in weeks: 8 to 11, 12 to 14, 15 to 19, 20 to 29, and >29 weeks.

Results:

A total of 2093 patients with NCT were included with median follow-up of 74 months and 71% NRT. The pCR rate was 2.1% with higher median OS compared with non-pCR (41 vs 19 months, P = .03). The pCR rate increased with longer NCT-S interval (quintiles: 1%, 1.6%, 1.7%, 3%, and 6%, P < .001, respectively). In logistic regression, NRT (odds ratio [OR] = 2.5, 95% confidence interval [CI]: 1.1-6.1, P = .03) and NCT-S >29 weeks (OR = 6.1, 95% CI = 2.02-18.50, P < .001) were predictive of increased pCR. The prolonged NCT-S interval and pCR were independent predictors of OS, whereas NRT was not.

Conclusions:

Longer NCT-S interval and pCR were independent predictors of improved OS in patients with PDAC. The NRT predicted increased pCR but not OS.

Pancreatic ductal adenocarcinoma: tumour regression grading following neoadjuvant FOLFIRINOX and radiation

AIMS

In the adjuvant setting, when compared to gemcitabine, patients with pancreatic ductal adenocarcinoma (PDAC) treated with FOLFIRINOX (Folinic Acid, Fluorouracil, Irinotecan, and Oxaliplatin) show superior survival. In this study, we quantitatively assess the pathological tumour response to chemoradiation in pancreatectomy specimens and reassess guidelines for tumour regression grading.

METHODS AND RESULTS

We evaluated 92 patients with borderline resectable/locally advanced PDAC following pancreatectomy and neoadjuvant treatment with FOLFIRINOX and radiation. Demographic data, CAP tumour regression grade (TRG) and overall survival (OS) were recorded. A quantitative analysis of residual tumour was performed on the slide with the highest tumour burden to derive a tumour-to-tumour bed ratio. On univariate analysis, only lymph node status (P = 0.043) and CAP TRG (P = 0.038) correlated with OS. Sixteen per cent of patients showed a complete pathological response. The optimal tumour-to-tumour bed ratio cut-point was 11.6%, and on a multivariate model was the only pathological parameter that correlated with OS (P = 0.016) (hazard ratio = 2.27).

CONCLUSIONS

The high proportion of patients with PDAC showing complete and near-complete pathological responses supports the use of FOLFIRINOX and radiation in the neoadjuvant setting. Several traditional pathology parameters fail to predict OS in patients treated with chemoradiation, while a quantitative tumour-to-tumour bed ratio is a powerful predictor of OS. The data support a two-tiered approach to TRG based on tumour-to-tumour bed ratio, and quantitative analysis merits further consideration.

Response to Preoperative Therapy in Localized Pancreatic Cancer

Evaluation of response to preoperative therapy for patients with pancreatic adenocarcinoma has been historically difficult. Therefore, preoperative regimens have generally been selected on the basis of baseline data such as radiographic stage and serum CA 19-9 level and then typically administered for a pre-specified duration as long as 6 months or more. The decision to proceed with resection following preoperative therapy likewise has rested upon the absence of disease progression rather than evidence for tumor response. This article reviews the basis for the evaluation of therapeutic response after preoperative therapy for pancreatic cancer in the existing scientific literature, and providing updates and new perspectives.

Impact of Neoadjuvant Chemoradiation on Pathologic Response in Patients With Localized Pancreatic Cancer

Introduction/Background: Multimodal neoadjuvant therapy has resulted in increased rates of histologic response in pancreatic tumors and adjacent lymph nodes. The biologic significance of the collective response in the primary tumor and lymph nodes is not understood.

Methods: Patients with localized PC who received neoadjuvant therapy and surgery with histologic assessment of the primary tumor and local-regional lymph nodes were included. Histopathologic response was classified using the modified Ryan score as follows: no viable cancer cells (CR), rare groups of cancer cells (nCR), residual cancer with evident tumor regression (PR), and extensive residual cancer with no evident tumor regression (NR). Nodal status was defined by number of lymph nodes (LN) with tumor metastases: N0 (0 LN), N1 (1–3), N2 (≥4).

Results: Of 341 patients with localized PC who received neoadjuvant therapy and surgery, 107 (31%) received chemoradiation alone, 44 (13%) received chemotherapy alone, and 190 (56%) received chemotherapy and chemoradiation. Histopathologic response consisted of 15 (4%) CRs, 59 (17%) nCRs, 188 (55%) PRs, and 79 (23%) NRs. Patients who received chemotherapy alone had the worst responses (n = 21 for NR, 48%) as compared to patients who received chemoradiation alone (n = 25 for NR, 24%) or patients who received both therapies (n = 33 for NR, 17%) (Table 1; p = 0.001). Median overall survival for all 341 patients was 39 months; OS by histopathologic subtype was not reached (CR), 49 months (nCR), 38 months (PR), and 34 months (NR), respectively (p = 0.004). Of the 341 patients, 208 (61%) had N0 disease, 97 (28%) had N1 disease, and 36 (11%) had N2 disease. In an adjusted hazards model, modified Ryan score of PR or NR (HR: 1.71; 95% CI: 1.15–2.54; p = 0.008) and N1 (HR: 1.42; 95% CI: 1.1.02–2.01; p = 0.04), or N2 disease (HR: 2.54, 95% CI: 1.64–3.93; p < 0.001) were associated with increased risk of death.

Conclusions: Neoadjuvant chemotherapy alone is associated with lower rates of pathologic response. Patients with CR or nCR have a significantly improved OS as compared to patients with PR or NR. Nodal status is the most important pathologic prognostic factor. Neoadjuvant chemoradiation may be an important driver of pathologic response.

Tumor Regression Grading Assessment in Locally Advanced Pancreatic Cancer After Neoadjuvant FOLFIRINOX: Interobserver Agreement and Prognostic Implications

Neoadjuvant therapy represents an increasingly used strategy in pancreatic cancer, and this means that more pancreatic resections need to be evaluated for therapy effect. Several grading systems have been proposed for the histological assessment of tumor regression in pre-treated patients with pancreatic cancer, but issues like practical application, level of agreement and prognostic significance are still debated. To date, a standardized and widely accepted score has not been established yet. In this study, two pathologists with expertise in pancreatic cancer used 4 of the most frequently reported systems (College of American Pathologists, Evans, MD Anderson, and Hartman) to evaluate tumor regression in 29 locally advanced pancreatic cancers previously treated with modified FOLFIRINOX regimen, to establish the level of agreement between pathologists and to determine their potential prognostic value. Cases were additionally evaluated with a fifth grading system inspired to the Dworak score, normally used for colo-rectal cancer, to identify an alternative, relevant option. Results obtained for current grading systems showed different levels of agreement, and they often proved to be very subjective and inaccurate. In addition, no significant correlation was observed with survival. Interestingly, Dworak score showed a higher degree of concordance and a significant correlation with overall survival in individual assessments. These data reflect the need to re-evaluate grading systems for pancreatic cancer to establish a more reproducible and clinically relevant score.

Characteristic and outcomes of patients with pathologic complete response after preoperative treatment in borderline and locally advanced pancreatic adenocarcinoma: An AGEO multicentric retrospective cohort

INTRODUCTION

Following publication of improved patients' outcome using first line FOLFIRINOX for metastatic pancreatic adenocarcinoma, many physicians now prescribe it as neo-adjuvant or induction treatment for borderline and locally advanced pancreatic cancer. A pathologic complete response, rarely seen with previous preoperative regimens, is sometimes observed in these patients. The aim of this study was to assess long-term outcomes of patients presenting pathologic complete response after preoperative FOLFIRINOX usually followed by chemo-radiation therapy for non-metastatic pancreatic adenocarcinoma.

MATERIAL AND METHODS

We retrospectively identified all resected patients with pancreatic cancer presenting pathologic complete response after FOLFIRINOX in 9 French centers from the AGEO group between November 2010 and May 2017.

RESULTS

29 patients were enrolled, 14 had borderline, 14 locally advanced and 1 oligo-metastatic pancreatic cancer. M/F ratio was 1.2 and the mean age was 57 years. All patients were treated with FOLFIRINOX (n = 29), de-escalated to gemcitabine (n = 1) and FOLFIRI (n = 2), and 24 (83 %) received radiation therapy after chemotherapy. Objective response rate to preoperative chemotherapy was 66% (RECIST V1.1). Only 8 patients received postoperative chemotherapy. After a median follow-up of 34 months from surgery, the median overall survival was not reached and the median disease free survival was 48 months. The 1-year and 2-year survival rates were 100% for OS and 96% and 72 % for DFS from surgery, 8 of the 9 observed recurrences were distant metastases.

CONCLUSIONS

The promising 1 and 2-year overall survival and disease free survival rates suggest that pathologic complete response is a major prognostic factor in resected pancreatic cancer following preoperative chemo-radiotherapy. A longer follow-up and prospective series are now necessary to confirm these encouraging results and to potentially validate pathologic complete response as a relevant surrogate marker of preoperative treatment efficacy.

Pathological complete response (pCR) with or without the residual intraductal carcinoma component following preoperative treatment for pancreatic cancer: Revisiting the definition of "pCR" from the prognostic standpoint

BACKGROUND AND AIM

There are no previous reports describing the prognostic significance of the residual intraductal carcinoma component (carcinoma in situ [CIS]) following preoperative treatment for pancreatic ductal adenocarcinoma (PDAC). The aim of the present study was to investigate the prognostic significance of a minimal residual CIS in cases with complete absence of an invasive component after preoperative treatment for PDAC.

METHODS

Eighty-one of 594 PDAC patients with preoperative treatment and subsequent surgery in our institute showed remarkable remission in the invasive component, which included 48 patients with the minimal residual invasive component (Min-inv group) and 33 with absence of an invasive component (No-inv group). We assessed the survival of these patients in association with the presence or absence of an invasive component and intraductal CIS.

RESULTS

Five-year overall survival in the No-inv group patients was significantly better than that of the Min-inv group patients (82%/66%, P = .041). Among the 33 patients in the No-inv group, residual CIS was observed in 16 patients (CIS-positive group), and the remaining 17 patients had no residual CIS (CIS-negative group). There was no significant difference in survival between patients in the CIS-positive and CIS-negative groups (92%/78%, P = .31).

CONCLUSIONS

Residual CIS in the absence of an invasive component after preoperative treatment does not yield a prognostic impact after receiving perioperative treatment for PDAC. It might be reasonable to define pathological complete response (pCR) from the prognostic standpoint as follows: pCR is the complete absence of an invasive carcinoma component regardless of residual CIS.

Long-term outcomes by response to neoadjuvant chemotherapy or chemoradiation in patients with resected pancreatic adenocarcinoma

BACKGROUND

Response of pancreatic adenocarcinoma to neoadjuvant chemotherapy (nCT) or chemoradiotherapy (nCRT) may be associated with prognosis, but long-term outcomes based on response to neoadjuvant therapy have not been well evaluated to date.

METHODS

The National Cancer Database was queried for patients with pancreatic adenocarcinoma receiving nCT/nCRT. To evaluate response to nCT/nCRT, comparisons were made from cT and cN stage to the respective post-neoadjuvant therapy ypT and ypN stages. Based on these comparisons, patients were classified as responders, progressors, or non-responders. Statistical analyses included estimation of survival using Kaplan-Meier analysis, as well as multivariable Cox proportional hazards modeling.

RESULTS

Of 2,028 patients, 30% had a response, 32% progressed, and 38% had no response; 1% of patients experienced pathologic complete response (pCR). Responders were more likely to have received multi-agent chemotherapy (P=0.0001) as well as radiotherapy (RT) (P=0.02) in the neoadjuvant setting. Response to nCT/nCRT was also associated with a higher R0 resection rate (P=0.02). At a median follow-up of 49 months, median overall survival (OS) was higher in responders than non-responders or progressors (29.9 vs. 24.3 vs. 22.2 months, P<0.001). The mean OS for patients experiencing pCR was 55.5 months. On multivariable analysis, treatment response was independently associated with OS (P=0.02).

CONCLUSIONS

Response to nCT/nCRT independently predicts long-term outcomes following resection of pancreatic adenocarcinoma; higher rates of treatment response were observed for patients receiving neoadjuvant RT as well as neoadjuvant multi-agent chemotherapy. These results may have implications on strategies to improve response rates.

Encapsulating fibrosis following neoadjuvant chemotherapy is correlated with outcomes in patients with pancreatic cancer

Pathological assessments of the treatment effect are critical for predicting patient outcomes after surgery. This study included 82 localized pancreatic cancer, 40 of whom were treated with neoadjuvant therapy (NAT) using four courses of gemcitabine plus nab-paclitaxel (GnP) followed by pancreatectomy (GnP group). The remaining 42 patients were treated with upfront pancreatectomy (UP) followed by adjuvant chemotherapy (UP group). We reviewed clinicopathological data of these patients to assess differences between the GnP and UP groups and further evaluate the prognostic impact of residual tumors after GnP treatment. Adjuvant treatment (S1, GnP or gemcitabine) was administered for 36 patients in the GnP group and 33 patients in the UP group. Compared to the UP group, the GnP group showed lower serum CA19-9 levels, microscopic tumor volume, and tumor-stroma ratio and decreased number of lymph node metastasis and vascular invasion. Higher incidence of encapsulating fibrosis was observed in the GnP group than in the UP group. Relative to the UP group (69%), a higher R0 rate was observed in the GnP group (85%). As for prognosis, encapsulating fibrosis was correlated with the overall survival of patients in the GnP group. However, overall survival did not show any correlation with other clinicopathological factors, including tumor reduction ratio (determined by computed tomography) and tumor regression grade (determined following criteria of Evans’ grading system or those of the College of American Pathologists). In conclusion, the present study revealed that GnP-induced encapsulating fibrosis could predict patients’ outcome. Nevertheless, large cohort studies are warranted to further evaluate the prognostic value of fibrosis, possibly with the help of imaging and biomarkers.

Is a Pathological Complete Response Following Neoadjuvant Chemoradiation Associated With Prolonged Survival in Patients With Pancreatic Cancer?

OBJECTIVES

To describe the survival outcome of patients with borderline resectable or locally advanced pancreatic ductal adenocarcinoma (BR/LA-PDAC) who have a pathologic complete response (pCR) following neoadjuvant chemoradiation.

BACKGROUND

Patients with BR/LA-PDAC are often treated with neoadjuvant chemoradiation in an attempt to downstage the tumor. Uncommonly, a pCR may result.

METHODS

A retrospective review of a prospectively maintained database was performed at a single institution. pCR was defined as no viable tumor identified in the pancreas or lymph nodes by pathology. A near complete response (nCR) was defined as a primary tumor less than 1 cm, without nodal metastasis. Overall survival (OS) and disease-free survival (DFS) were reported.

RESULTS

One hundred eighty-six patients with BR/LA-PDAC underwent neoadjuvant chemoradiation and subsequent pancreatectomy. Nineteen patients (10%) had a pCR, 29 (16%) had an nCR, and the remaining 138 (74%) had a limited response. Median DFS was 26 months in patients with pCR, which was superior to nCR (12 months, P = 0.019) and limited response (12 months, P < 0.001). The median OS of nCR (27 months, P = 0.003) or limited response (26 months, P = 0.001) was less than that of pCR (more than 60 months). In multivariable analyses pCR was an independent prognostic factor for DFS (HR = 0.45; 0.22-0.93, P = 0.030) and OS (HR=0.41; 0.17-0.97, P = 0.044). Neoadjuvant FOLFIRINOX (HR=0.47; 0.26-0.87, P = 0.015) and negative lymph node status (HR=0.57; 0.36-0.90, P = 0.018) were also associated with improved survival.

CONCLUSIONS

Patients with BR/LA-PDAC who had a pCR after neoadjuvant chemoradiation had a significantly prolonged survival compared with those who had nCR or a limited response.

Clinical Characteristics of Patients Experiencing Pathologic Complete Response Following Neoadjuvant Therapy for Borderline Resectable/Locally Advanced Pancreatic Adenocarcinoma

OBJECTIVES

The purpose of this study is to describe clinical characteristics and outcomes of patients with borderline resectable pancreatic cancer (BRPC) or locally advanced pancreatic cancer (LAPC) who achieved pathologic complete response (pCR) following neoadjuvant therapy.

MATERIALS AND METHODS

A single institution clinical database for patients with pancreatic ductal adenocarcinoma was queried. Between 2008 and 2014 patients were identified with BRPC and LAPC, who underwent surgical resection after receiving neoadjuvant treatment. Clinical and pathologic features of the patients who achieved pCR were acquired retrospectively.

RESULTS

Six patients were identified to have pCR on pathology of the postoperative specimen. On the basis of pretreatment clinical staging, 2 patients were considered to have BRPC and 4 LAPC. Four patients received gemcitabine-based chemotherapy and 2 patients received FOLFIRINOX (5-fluorouracil, oxaliplatin, irinotecan, and leucovorin). Five of 6 patients received radiation therapy before operative resection. Operative procedures included distal pancreatectomy (n=3) and pancreatoduodenectomy (n=3). Pancreatic intraepithelial neoplasia 1 to 2 was present in 3 cases, and pancreatic intraepithelial neoplasia 3 in 1 case. During a median follow-up of 21.3 months, 2 patients died, with a median survival of 11.0 months (range, 10.4 to 11.6 mo). Four patients are alive and continue to follow-up with median survival of 28.7 months (range, 20.1 to 42.4 mo).

CONCLUSIONS

Multimodality neoadjuvant therapy may lead to complete pathologic response in a small number of patients with borderline resectable/locally advanced pancreatic adenocarcinoma. pCR to neoadjuvant therapy does not lead to cure in most cases, and the majority of patients appear to relapse locally or systemically.