2015 American Society of Clinical Oncology Annual Meeting:

Tumor Stroma Shown to Be a Biomarker in Pancreatic Adenocarcinoma

The quantification of tumor stroma as a biomarker in pancreatic adenocarcinoma was the topic of a presentation by Robert J. Torphy, BS, of the University of North Carolina, School of Medicine at Chapel Hill. Mr. Torphy spoke at the 2015 Annual Meeting of the American Society of Clinical Oncology (ASCO), which was held in Chicago.

Role of Desmoplastic Tumor Stroma in the Progression and Metastasis of Pancreatic Adenocarcinoma Needed Clarification
Desmoplastic tumor stroma characterizes the primary tumor in pancreatic ductal adenocarcinoma, but its role in tumor progression and metastasis is less clear.

Presence and Prognostic Significance of Tumor Stroma Were Evaluated
The presence and prognostic significance of tumor stroma at primary and metastatic sites were evaluated. Tissue sections of primary tumors from 57 patients who underwent curative resections and 46 primary and metastatic tumors from 15 patients with metastatic pancreatic cancer were digitally annotated for tumor epithelium and tumor stroma, reviewed by a pathologist, and quantified using the Spectrum WebScope.

Tumor stroma density (TSD) was quantified as tumor stroma per total tumor area. Resected patients received no adjuvant chemotherapy. The association of TSD with overall and recurrence-free survival was calculated using the multivariate Cox proportional hazards model.

Stromal Content Shown to be a Measurable Biomarker with Meaningful Clinical Associations
Median TSD in primary tumors was 0.57. TSD was no different in the primary tumors of patients who had localized compared to metastatic disease. TSD was decreased in solid organ (0.12) and lymph node metastases (0.22) (P=0001).

In patients who underwent curative resections, high TSD was associated with longer overall survival (hazard ratio = 0.237; P =.009), with a median overall survival of 11 months in the low-TSD (<0.57) group and 21.5 months in the high-TSD (≥0.57) group. TSD was also associated with relapse-free survival (hazard ratio = 0.286, P=.022), with a median relapse-free survival of 9 months in the low TSD group and 19 months in the high TSD group.

The association of TSD with overall and relapse-free survival was adjusted for tumor grade, T, N, overall stage, American Society of Anesthesiologists score, and smoking status.

Conclusions

  • Stromal content was demonstrated to be a measurable biomarker in pancreatic adenocarcinoma, with meaningful clinical associations.
  • TSD should be used as an objective, quantitative assessment of tumor stroma in correlative and therapeutic trials of pancreatic cancer. Tumor stroma appears to be associated with restraining tumor growth with decreasing TSD in patients with more aggressive disease.
  • Low TSD at metastatic sites should be considered in the context of stroma-modulating therapies.

June 30, 2015

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