CA 19-9 Response: A Surrogate to Predict Survival in Patients With Metastatic Pancreatic Adenocarcinoma

Liquid Biopsy in Pancreatic Ductal Adenocarcinoma: A Review of Methods and Applications

Pancreatic ductal adenocarcinoma (PDAC) remains a malignancy with one of the highest mortality rates. One limitation in the diagnosis and treatment of PDAC is the lack of an early and universal biomarker. Extensive research performed recently to develop new assays which could fit this role is available. In this review, we will discuss the current landscape of liquid biopsy in patients with PDAC. Specifically, we will review the various methods of liquid biopsy, focusing on circulating tumor DNA (ctDNA) and exosomes and future opportunities for improvement using artificial intelligence or machine learning to analyze results from a multi-omic approach. We will also consider applications which have been evaluated, including the utility of liquid biopsy for screening and staging patients at diagnosis as well as before and after surgery. We will also examine the potential for liquid biopsy to monitor patient treatment response in the setting of clinical trial development.

Differential impact of incrementally elevated CA 19-9 levels on prognosis of resected pancreatic ductal adenocarcinoma

BACKGROUND

CA 19-9 is an extremely useful biomarker for pancreatic ductal adenocarcinomas (PDACs). However, the optimal cut-off and prognostic significance at higher cut-offs are yet to be determined.

METHODS

Retrospective analysis included patients with PDAC who underwent curative resection from January 2010 to May 2020 at Tata Memorial Centre, Mumbai. The pretherapy CA 19-9 was dichotomized using various cut-off levels and analysed.

RESULTS

In 244 included patients, the median overall survival (OS) for those with CA19-9 level (IU/ml) < or >78, 200, 500, 1000, and 2000 was 27, 24, 23, 22, 21 months versus 18, 16, 15, 14, 13 months; respectively, and was statistically significant (p-value- 0.002, 0.001, 0.002, 0.002 and 0.004, respectively). The number of recurrences and mortality had significant correlation with CA 19-9 cut-offs. On multivariate analysis, adjuvant treatment completion (p-0.004) and decreasing or stable CA19-9 after Neoadjuvant therapy (NAT) (p- 0.031) were associated with improved OS.

CONCLUSION

The prognostic significance of CA 19-9 was observed at all the cut-off levels examined, beyond mere elevated value as per the standard cut-off level. In patients with high CA19-9 level, surgery should be offered if technically and conditionally feasible, only when a response in CA19-9 level to NAT is achieved.

Neoadjuvant therapy for localized pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive tumor with poor prognosis and rising incidence globally. Multimodal therapy that includes surgical resection and chemotherapy with or without radiation offers the best chance for optimal outcomes. The development of established criteria for anatomic staging of local primary tumors into potentially resectable (PR), borderline resectable (BR), and locally advanced (LA) has greatly clarified the optimal treatment strategies. While upfront surgical resection was traditionally the recommended approach for localized PDAC, increasingly neoadjuvant therapy (NT) is recommended prior to surgery. Whereas NT can lead to downstaging that facilitates surgical resection for BR/LA cancers, NT also enhances patient selection for surgery, improves margin-negative resection rates, and increases the odds of completing multimodality therapy for all patients with PDAC. Herein, we review the rationale for NT for localized PDAC and summarize existing and ongoing literature.

Multimodal Approaches to Patient Selection for Pancreas Cancer Surgery

With an overall 5-year survival rate of 12%, pancreas ductal adenocarcinoma (PDAC) is an aggressive cancer that claims more than 50,000 patient lives each year in the United States alone. Even those few patients who undergo curative-intent resection with favorable pathology reports are likely to experience recurrence within the first two years after surgery and ultimately die from their cancer. We hypothesize that risk factors for these early recurrences can be identified with thorough preoperative staging, thus enabling proper patient selection for surgical resection and avoiding unnecessary harm. Herein, we review evidence supporting multidisciplinary and multimodality staging, comprehensive neoadjuvant treatment strategies, and optimal patient selection for curative-intent surgical resections. We further review data generated from our standardized approach at the Mayo Clinic and extrapolate to inform potential future investigations.

Increasing Systemic Immune-inflammation Index During Treatment in Patients With Advanced Pancreatic Cancer is Associated With Poor Survival: A Retrospective, Multicenter, Cohort Study

BACKGROUND AND OBJECTIVES

A high systemic immune-inflammation index (SIII) at diagnosis of various cancers, including pancreatic cancer, is associated with poor prognosis. The impact of FOLFIRINOX (5-fluorouracil, leucovorin, irinotecan, and oxaliplatin) chemotherapy or stereotactic body radiotherapy on this index is unknown. In addition, the prognostic value of changes in the SIII during treatment is unclear. In this retrospective analysis, we aimed to find answers regarding patients with advanced pancreatic cancer.

METHODS

Patients with advanced pancreatic cancer treated with FOLFIRINOX chemotherapy alone or with FOLFIRINOX chemotherapy followed by stereotactic body radiotherapy between 2015 and 2021 in 2 tertiary referral centers were included. Baseline characteristics, laboratory values at 3 time points during treatment, and survival outcomes were collected. The patient-specific evolutions of SIII and their association with mortality were assessed with joint models for longitudinal and time-to-event data.

RESULTS

Data of 141 patients were analyzed. At a median follow-up time of 23.0 months (95% CI: 14.6-31.3), 97 (69%) patients had died. Median overall survival was 13.2 months (95% CI: 11.0-15.5). During treatment with FOLFIRINOX, the log (SIII) was reduced by -0.588 (95% CI: -0.0978, -0.197; P = 0.003). One unit increase in log (SIII) increased the hazard ratio of dying by 1.604 (95% CI: 1.068-2.409; P = 0.023).

CONCLUSIONS

In addition to carbohydrate antigen 19-9, the SIII is a reliable biomarker in patients with advanced pancreatic cancer.

A novel autoantibody signatures for enhanced clinical diagnosis of pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease that requires precise diagnosis for effective treatment. However, the diagnostic value of carbohydrate antigen 19 - 9 (CA19-9) is limited. Therefore, this study aims to identify novel tumor-associated autoantibodies (TAAbs) for PDAC diagnosis.

METHODS

A three-phase strategy comprising discovery, test, and validation was implemented. HuProt™ Human Proteome Microarray v3.1 was used to screen potential TAAbs in 49 samples. Subsequently, the levels of potential TAAbs were evaluated in 477 samples via enzyme-linked immunosorbent assay (ELISA) in PDAC, benign pancreatic diseases (BPD), and normal control (NC), followed by the construction of a diagnostic model.

RESULTS

In the discovery phase, protein microarrays identified 167 candidate TAAbs. Based on bioinformatics analysis, fifteen tumor-associated antigens (TAAs) were selected for further validation using ELISA. Ten TAAbs exhibited differentially expressed in PDAC patients in the test phase (P < 0.05), with an area under the curve (AUC) ranging from 0.61 to 0.76. An immunodiagnostic model including three TAAbs (anti-HEXB, anti-TXLNA, anti-SLAMF6) was then developed, demonstrating AUCs of 0.81 (58.0% sensitivity, 86.0% specificity) and 0.78 (55.71% sensitivity, 87.14% specificity) for distinguishing PDAC from NC. Additionally, the model yielded AUCs of 0.80 (58.0% sensitivity, 86.25% specificity) and 0.83 (55.71% sensitivity, 100% specificity) for distinguishing PDAC from BPD in the test and validation phases, respectively. Notably, the combination of the immunodiagnostic model with CA19-9 resulted in an increased positive rate of PDAC to 92.91%.

CONCLUSION

The immunodiagnostic model may offer a novel serological detection method for PDAC diagnosis, providing valuable insights into the development of effective diagnostic biomarkers.

Dynamics of the prognostic nutritional index in preoperative chemotherapy in patients with colorectal liver metastases

BACKGROUND

Identifying the prognostic indicators that reflect the efficacy of preoperative chemotherapy is necessary. In this study, we investigated the prognostic indicators targeting the systemic inflammatory response for the administration of preoperative chemotherapy in patients with colorectal liver metastases.

METHODS

Data for 192 patients were retrospectively analyzed. The relationship between overall survival and clinicopathological variables, including biomarkers such as the prognostic nutritional index, was investigated in patients who underwent upfront surgery or preoperative chemotherapy.

RESULTS

In the upfront surgery group, extrahepatic lesion (p=0.01) and low prognostic nutritional index (p < 0.01) were significant prognostic indicators, whereas a decrease in the prognostic nutritional index (p=0.01) during preoperative chemotherapy were independent poor prognostic factors in the preoperative chemotherapy group. In particular, a decrease in the prognostic nutritional index was a significant prognostic marker in patients aged <75 years (p=0.04). In patients with a low prognostic nutritional index aged <75 years, preoperative chemotherapy significantly prolonged overall survival (p=0.02).

CONCLUSION

A decrease in the prognostic nutritional index during preoperative chemotherapy predicted overall survival of patients with colorectal liver metastases after hepatic resection, and preoperative chemotherapy may be effective for patients aged <75 years with a low prognostic nutritional index.

Combining sCD163 with CA 19-9 Increases the Predictiveness of Pancreatic Ductal Adenocarcinoma

The objective of this study was to evaluate the diagnostic and prognostic potential of soluble CD163 (sCD163) in patients with pancreatic ductal adenocarcinoma (PDAC). Preoperative serum samples from 255 patients with PDAC were analyzed for sCD163 using a commercially available enzyme-linked immunosorbent assay. The diagnostic value of sCD163 was evaluated using receiver operating characteristic (ROC) curves. The prognostic significance of sCD163 was evaluated by Cox regression analysis and Kaplan-Meier survival curves. sCD163 was significantly increased in patients with PDAC, across all stages, compared to healthy subjects (stage 1: p value = 0.033; stage 2-4: p value ≤ 0.0001). ROC curves showed that sCD163 combined with CA 19-9 had the highest diagnostic potential compared to sCD163 and CA 19-9 alone both in patients with local PDAC and patients with advanced PDAC. Univariate and multivariate analysis showed no association between sCD163 and overall survival. This study found elevated levels of circulating sCD163 in patients with PDAC, regardless of stage, compared to healthy subjects. This suggests that sCD163 may have a clinical value as a novel diagnostic biomarker in PDAC.

Routine neoadjuvant chemotherapy for all patients with resectable pancreatic ductal adenocarcinoma? A review of the evidence

Pancreatic ductal adenocarcinoma is an aggressive malignancy that carries a poor prognosis because the majority of patients present with locally advanced or metastatic disease. However, even patients who are fortunate enough to present with resectable disease are often plagued by high recurrence rates. While adjuvant chemotherapy has been shown to decrease the risk of recurrence after surgery, post operative complications and poor performance status after surgery prevent up to 50% of patients from receiving it. Given the benefits of neoadjuvant therapy in patients with borderline resectable disease, it is understandable that neoadjuvant therapy has been steadily increasing in patients with resectable cancers as well. In this review paper, we highlight the rational and existing evidence of using neoadjuvant therapy in all patients with resectable pancreatic adenocarcinoma.

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.

Prediction of response to systemic treatment by kinetics of circulating tumor DNA in metastatic pancreatic cancer

Introduction

Pretherapeutic detectable circulating tumor DNA (ctDNA) represents a promising prognostic biomarker for predicting relapse and overall survival in patients with metastatic pancreatic cancer. However, the prognostic value of ctDNA dynamics during treatment has not been studied thus far. We aimed to investigate the correlation between the change of ctDNA levels and response to treatment in patients treated by systemic therapy.

Material and methods

CtDNA detection using liquid biopsy (droplet digital PCR (ddPCR) utilizing KRAS G12/13 and, if negative, Q61 commercial test kits) was prospectively performed on patients with stage IV pancreatic cancer i) prior to initiation of systemic chemotherapy and ii) serially every 2 weeks until restaging. Detection rates, levels of ctDNA, and the course of the relative ctDNA change (ctDNA kinetics) were correlated to treatment response and clinical outcome.

Results

The detection rate at baseline was 64.3% (45/70), and complete serial measurement records were available for 32 ctDNA-positive patients. Reduction of ctDNA levels below 57.9% of its baseline value at week 2 after treatment initiation was significantly predictive of response to treatment (area under the curve (AUC) = 0.918, sensitivity 91.67%, and specificity 100%) and was associated with prolonged overall survival (OS) (5.7 vs. 11.4 months, p = 0.006) and progression-free survival (PFS) (2.5 vs. 7.7 months, p < 0.000) regardless of treatment line. Pretherapeutic ctDNA detection was independently associated with worse OS in patients receiving a first-line regimen (7 vs. 11.3 months, p = 0.046) and regardless of treatment line (11.4 vs. 15.9 months, p = 0.045) as well as worse PFS (3.4 vs. 10.8 months, p = 0.018).

Conclusion

The change in magnitude of ctDNA during systemic treatment allows the prediction of treatment response and is associated with both OS and PFS. This finding adds significant clinical potential to the already established prognostic value of ctDNA positivity in metastatic pancreatic cancer.

Circulating Protein Biomarkers for Prognostic Use in Patients with Advanced Pancreatic Ductal Adenocarcinoma Undergoing Chemotherapy

Patients with advanced pancreatic ductal adenocarcinoma (PDAC) have a dismal prognosis. We aimed to find a prognostic protein signature for overall survival (OS) in patients with advanced PDAC, and to explore whether early changes in circulating-protein levels could predict survival. We investigated 92 proteins using the Olink Immuno-Oncology panel in serum samples from 363 patients with advanced PDAC. Protein panels for several survival cut-offs were developed independently by two bioinformaticians using LASSO and Ridge regression models. Two panels of proteins discriminated patients with OS < 90 days from those with OS > 2 years. Index I (CSF-1, IL-6, PDCD1, TNFRSF12A, TRAIL, TWEAK, and CA19-9) had AUCs of 0.99 (95% CI: 0.98−1) (discovery cohort) and 0.89 (0.74−1) (replication cohort). For Index II (CXCL13, IL-6, PDCD1, and TNFRSF12A), the corresponding AUCs were 0.97 (0.93−1) and 0.82 (0.68−0.96). Four proteins (ANGPT2, IL-6, IL-10, and TNFRSF12A) were associated with survival across all treatment groups. Longitudinal samples revealed several changes, including four proteins that were also part of the prognostic signatures (CSF-1, CXCL13, IL-6, TNFRSF12A). This study identified two circulating-protein indices with the potential to identify patients with advanced PDAC with very short OS and with long OS.

Retrospective Evaluation of Treatment Response in Patients with Nonmetastatic Pancreatic Cancer Using CT and CA 19-9

Background Imaging studies have limitations in evaluating pancreatic ductal adenocarcinoma (PDAC) treatment response. Purpose To investigate the effectiveness of combined CT and carbohydrate antigen 19-9 (CA 19-9) evaluation at 8 weeks after first-line treatment to predict overall survival (OS) of patients with nonmetastatic PDAC. Materials and Methods Patients with nonmetastatic PDAC who received first-line treatment with either chemotherapy or concurrent chemoradiation in a single-center PDAC cohort registry were retrospectively enrolled in the study between January 2013 and December 2016. Follow-up CT images obtained 8 weeks after treatment were evaluated according to Response Evaluation Criteria in Solid Tumors. Patients with partial response (PR) or stable disease (SD) were defined as CT responders, and those with progressive disease (PD) were defined as CT nonresponders. Patients with a normalized CA 19-9 level at 8-week follow-up were defined as CA 19-9 responders, and those with a nonnormalized or nonelevated CA 19-9 level were defined as CA 19-9 nonresponders. OS was compared using the Kaplan-Meier method with Breslow analysis. Results A total of 197 patients (mean age ± standard deviation, 65 years ± 10; 107 men) were evaluated. Patients with PD (n = 17) showed shorter OS than those with SD (n = 147; P < .001) or PR (n = 33; P = .003). OS did not differ between the patients with PR and those with SD (P = .60). When the CT and CA 19-9 responses were integrated, OS was longest in CT and CA 19-9 responders (group 1, n = 27; median OS, 26.6 months [95% CI: 9.0, 44.1]), followed by CT responders but CA 19-9 nonresponders (group 2, n = 153; median OS, 15.9 months [95% CI: 13.3, 18.5]; P = .007 vs group 1) and CT and CA 19-9 nonresponders (group 3, n = 17; median OS, 6.5 months [95% CI: 0.8, 12.2]; P < .001 vs group 2). Conclusion Integrated evaluation with CT and carbohydrate antigen 19-9 response allowed more accurate stratification of survival in patients with pancreatic ductal adenocarcinoma in the early treatment period than did evaluation according to Response Evaluation Criteria in Solid Tumors. © RSNA, 2022 Online supplemental material is available for this article.

The Association of Real-World CA 19-9 Level Monitoring Patterns and Clinical Outcomes Among Patients With Metastatic Pancreatic Ductal Adenocarcinoma

Background

Pancreatic cancer is expected to be the third deadliest cancer in the US in 2021. Evaluation of treatment response in patients with mPDAC necessitates scheduled clinical and radiographic assessments along with monitoring serum CA 19-9 levels. Currently available single-institution data examining the importance of CA 19-9 monitoring cannot be generalized to real-world settings. We investigated the impact of serum CA 19-9 monitoring and its association with clinical outcomes in patients with mPDAC in a population-based setting.

Methods

Data were extracted from the Flatiron Health electronic health record (EHR)-derived de-identified database for patients diagnosed with mPDAC between January 1, 2015, and June 30, 2020. Serum CA 19-9 levels at baseline – defined as the values obtained ≤ 60 days prior to treatment initiation - and during treatment were extracted. CA 19-9 levels > 40 IU/mL were considered elevated. Survival outcomes were compared based on testing frequency, baseline CA 19-9 levels, and change in CA 19-9.

Results

6,118 patients with mPDAC who received treatment were included in the analysis. The median age at diagnosis was 68 years (IQR: 61-75). Patients with normal baseline CA 19-9 experienced longer median survival than patients with elevated levels [1L: 8.8 months (95% CI: 7.9 - 10) vs. 7.2 months (6.8 – 7.5), p < 0.001; 2L: 7.2 months (6.1 – 9.2) vs. 5.2 months (4.9 – 5.6), p < 0.001; 3L: 6.1 months (5.4 – 9.1) vs. 3.9 months (3.4 – 4.3), p < 0.001]. Patients with decreasing/stable CA 19-9 during treatment experienced longer survival than patients who experienced an increase in CA 19-9 levels [1L: 10.9 months (10.5 – 11.3) vs. 5.4 months (5.1 – 5.9), p < 0.0001; 2L: 8.2 months (7.7 – 8.5) vs. 4.3 months (4.1 – 4.7), p < 0.001; 3L: 7.5 months (6.6 – 9.2) vs. 3.7 months (3.4 – 4.3), p < 0.001].

Conclusions

In one of the largest, contemporary, real-world studies of patients with mPDAC, elevated CA 19-9 level at treatment initiation demonstrated a prognostic impact. Routine serial monitoring of CA 19-9 levels during treatment may be warranted, in addition to clinical and radiographic assessment, and may translate into better patient outcomes. Further validation studies are needed to understand the generalizability of these results.

Trends in the utilization of neoadjuvant therapy for pancreatic ductal adenocarcinoma

For patients with localized pancreatic cancer, neoadjuvant therapy (NT) is increasingly delivered before surgery to maximize the receipt of multimodality therapy and the odds of a margin-negative resection. Three decades of refining the use of NT have led to its acceptance as a valid treatment approach for pancreatic adenocarcinoma. In this review, we discuss the rationale for and recent global trends in the utilization of NT for patients with pancreatic cancer.

Glycemic Control as an Early Prognostic Marker in Advanced Pancreatic Cancer

PURPOSE

Impaired glucose metabolism is present in most patients with pancreatic ductal adenocarcinoma (PDAC). Whereas previous studies have focused on pre-treatment glycemic indices and prognosis in those with concomitant diabetes, the effects of glycemic control during chemotherapy treatment on prognosis, in patients with and without diabetes, have not been well characterized. We examined the relationship between early glycemic control and overall survival (OS) in a cohort of patients with advanced PDAC treated in a community setting.

PATIENTS AND METHODS

Seventy-three patients with advanced PDAC (38% with diabetes) receiving chemotherapy while participating in a biobanking clinical trial were included. Clinical characteristics and laboratory results during 1 year were obtained from the electronic medical record. Kaplan-Meier estimate, log-rank test and hazard ratios were computed to assess the effect of glycemic control on OS. The Cox proportional hazards regression model was applied to ascertain the significance of glycemic control with other survival variables.

RESULTS

One thousand four hundred eighteen random blood glucose (RBG) values were analyzed. In accord with previous findings, a 50% decline in the serum tumor marker CA 19-9 at any time was predictive of survival (P=0.0002). In univariate analysis, an elevated pre-treatment average RBG, 3-month average RBG (RBG-3) and the FOLFIRINOX regimen were associated with longer survival. Based on ROC analysis (AUC=0.82), an RBG-3 of 120 mg/dl was determined to be the optimal cutoff to predict 12-month survival. In multivariate analysis that included age, stage, BMI, performance status, presence of diabetes, and chemotherapy regimen, only RBG-3 maintained significance: an RBG-3 ≤120 mg/dl predicted for improved OS compared to >120 mg/dl (19 vs. 9 months; HR=0.37, P=0.002). In contrast, an early decline in CA 19-9 could not predict OS.

CONCLUSION

Lower glucose levels during the first 3 months of treatment for advanced PDAC predict for improved OS in patients both with and without diabetes. These results suggest that RBG-3 may be a novel prognostic biomarker worthy of confirmation in a larger patient cohort and that studies exploring a possible cause and effect of this novel survival-linked relationship are warranted.

Time to CA19-9 nadir: a clue for defining optimal treatment duration in patients with resectable pancreatic ductal adenocarcinoma

BACKGROUND

Defining optimal treatment duration in patients with resectable pancreatic ductal adenocarcinoma (PDAC) receiving primary chemotherapy is an unmet need. The role of time to CA19-9 nadir and of nadir magnitude was explored in this study.

PATIENTS AND METHODS

The databases of our institution's prospective trials were queried to speculate on the time to maximum chemotherapy response. Patients with pathologically proven, metastatic (N = 356) or non-metastatic non-resected (N = 163) PDAC and elevated baseline (> 34 UI/mL) CA19-9 were analyzed. Survival curves were estimated using the Kaplan-Meier method and compared by means of the log-rank test for analyses including at least 45 patients. Multivariable Cox proportional hazards model was used to estimate clinical features for their association with OS. All probability values were from two-sided tests.

RESULTS

Time to CA19-9 nadir was ≥ 4 months in 184 of 346 (53%) metastatic and 121 of 163 (74%) non-metastatic patients (p = 0.002). The likelihood of a later nadir was higher with taxane-based chemotherapy as compared to taxane-free combinations (73% versus 56%; p = 0.02). Both metastatic and non-metastatic patients had significantly longer survival when nadir occurred later. Patients with a larger CA19-9 nadir magnitude had significantly longer survival. Metastatic patients with CA19-9 reduced by < 50%, 50-89%, or > 89% and had a median survival of 7.4, 9.8, and 14.7 months, respectively (p ≤ 0.001 for all comparisons). The corresponding figures for non-metastatic patients were 10.6; 17.0; and 18.7 months, respectively (p ≤ 0.02 for < 50% versus 50-89% or > 89%; p = 0.14 for 50-89% versus > 89%). Multivariable analyses showed that time to CA19-9 nadir but not CA19-9 nadir magnitude was independently predictive of survival.

CONCLUSION

The present study suggests that a 4-6 months program might be a more suitable candidate for prospective assessment in comparison to shorter pre-defined period in patients who are candidates to surgery after primary chemotherapy.