Radiographic and Serologic Response to First-Line Chemotherapy in Unresected Localized Pancreatic Cancer

Abstract

Background: This study aimed to determine the clinical relevance of putative radiographic and serologic metrics of chemotherapy response in patients with localized pancreatic cancer (LPC) who do not undergo pancreatectomy. Studies evaluating the response of LPC to systemic chemotherapy have focused on histopathologic analyses of resected specimens, but such specimens are not available for patients who do not undergo resection. We previously showed that changes in tumor volume and CA 19-9 levels provide a clinical readout of histopathologic response to preoperative therapy. Methods: Our institutional database was searched for patients with LPC who were treated with first-line chemotherapy between January 2010 and December 2017 and did not undergo pancreatectomy. Radiographic response was measured using RECIST 1.1 and tumor volume. The volume of the primary tumor was compared between pretreatment and posttreatment images. The percentage change in tumor volume (%Δvol) was calculated as a percentage of the pretreatment volume. Serologic response was measured by comparing pretreatment and posttreatment CA 19-9 levels. We established 3 response groups by combining these metrics: (1) best responders with a decline in %Δvol in the top quartile and in CA 19-9, (2) nonresponders with an increase in %Δvol and in CA 19-9, and (3) other patients. Results: This study included 329 patients. Individually, %Δvol and change in CA 19-9 were associated with overall survival (OS) (P≤.1), but RECIST 1.1 was not. In all, 73 patients (22%) were best responders, 42 (13%) were nonresponders, and there were 214 (65%) others. Best responders lived significantly longer than nonresponders and others (median OS, 24 vs 12 vs 17 months, respectively; P<.01). A multivariable model adjusting for type of chemotherapy regimen, number of chemotherapy doses, and receipt of radiotherapy showed that best responders had longer OS than did the other cohorts (hazard ratio [HR], 0.35; 95% CI, 0.21–0.58 for best responders, and HR, 0.55; 95% CI, 0.37–0.83 for others). Conclusions: Changes in tumor volume and serum levels of CA 19-9—but not RECIST 1.1—represent reliable metrics of response to systemic chemotherapy. They can be used to counsel patients and families on survival expectations even if pancreatectomy is not performed.

Development and validation of a nomogram model based on pretreatment ultrasound and contrast-enhanced ultrasound to predict the efficacy of neoadjuvant chemotherapy in patients with borderline resectable or locally advanced pancreatic cancer

“…According to the published literature, clinical response in patients were evaluated based on the Response Evaluation Criteria in Solid Tumors (RECIST, version 1.1) combined with the changes of serum levels of cancer antigen 19–9 (CA 19–9) [ 18 , 19 ].…”

“…Serum CA19-9 levels were detected before and after treatment. Serologic responders were defined according to the published literature [ 19 , 21 ]. Baseline CA19-9 were classified as: (1) normal CA19-9 (≤ 34 U/mL); (2) elevated CA19-9 (> 34 U/mL).…”

Extracellular volume-based scoring system for tracking tumor progression in pancreatic cancer patients receiving intraoperative radiotherapy

“…IORT is recommended as experts’ consensus to perform on LAPC patients to relieve symptoms and obtain extra benefits [ 4 , 5 ]. Around 50–80% of pancreatic ductal adenocarcinoma (PDAC) patients were assessed as stable disease (SD) based on response evaluation criteria in solid tumor version 1.1 (RECIST v.1.1) after treatment [ 6 ]. Despite no significant change in tumor diameter in these patients, some of them could achieve major pathologic response and better prognosis [ 7 ].…”

Combined CT and serum CA19-9 for stratifying risk for progression in patients with locally advanced pancreatic cancer receiving intraoperative radiotherapy

“…Nevertheless, the prognosis of LAPC patients after IORT varied significantly due to the heterogeneity and complexity of pancreatic cancer (12). Instead of benefiting, patients who are insensitive to IORT might progress rapidly after surgery and suffer a series of complications, toxicities, and financial losses (10).…”