Short summary

In this study we will investigate the use of circulating tumor DNA (ctDNA) as a biomarker for upper gastrointestinal (UGI) cancer. We will investigate if ctDNA analysis holds diagnostic, predictive and prognostic value and if it can be used for monitoring of changes in tumor load during treatment and disease progression.

Rationale

Background

UGI cancers cover cancers of the esophagus, stomach and pancreas and have 5 year survival rates ranging from 18% to as low as 6%. Treating these diseases is very challenging because the tumors are often discovered late due to unspecific symptoms and are thus often at advanced stage at the time of diagnosis. Furthermore, the current methods for assessment and monitoring of tumor load are instufficient. This makes it hard to correctly determine stage and dissemination of the tumor at diagnosis and to monitor changes in tumor load in response to therapy or due to recurrence of primary tumor or development of metastatic deposits. A promising solution is to use ctDNA as a biomarker. Cell-free DNA (cfDNA) is found in the blood of all individuals - ctDNA is the fraction of cfDNA that originates from cancer cells and is thus only present in individuals with cancer. Detection of ctDNA may provide a highly specific and minimally invasive way to assess tumor load in cancer patients.

Methods and materials

In this study we will collect and investigate tumor and blood samples from 160 UGI cancer patients, including 120 patients with multiple time-separated blood samples collected during treatment and follow-up. We will be using two methods for ctDNA detection; highly sensitive quantificantion of tumor-specific breakpoints in cfDNA and direct sequencing of cfDNA to detect large copy number aberrations without prior analysis of the tumor. The ctDNA analyses will be compared to tumor stage and dissemination determined by the pathologist, to CT scans, and to clinical outcome.

Expected outcome and persepctives

The first method may provide a novel method for assessment of tumor load and dissemination, for monitoring of changes in tumor load during disease progression, and for early detection of disease recurrence. Especially these days where new promising targetted drugs are being developed, early detection of recurrence is of utmost importance for the efficient testing and implementation of these new treatment modalities., The second method may in the future allow for population-based screening for early detection of cancer.

Description of the cohort

The cohort includes 160 patients with upper gastrointestinal cancer, i.e. cancers of the esophagus, stomach and pancreas. Patients are identified and recruited when presenting with upper gastrointestinal cancer at Upper GI Section, Department of Surgery, Odense University Hospital.

Patients are divided in to six sub-groups:

1. ECV1: patients with early-stage esophageal or stomach cancer (< or eaqual to T2 and N0, M0). N = 10
2. ECV2: patients with localized esophageal or stomach cancer (>T2, regardless of N stage, M0). N = 60
3. ECV3: patients with late-stage, locally advanced esophageal or stomach cancer and sometimes also distant metastasis. N = 10
4. PC1: patients with localized pancreatic cancer. N = 60
5. PC2: patients with locally advanced pancreatic cancer but no distant metastases. N = 10
6. PC3: patients with pancreatic cancer and distant metastasis. N = 10

Data and biological material

Clinical data:

• Pathological stage of tumor
• Imaging results
• Treatment information
• Other data related to disease progression

Biological material:

• Tumor biopsies from the surgically removed tumor or left-over tissue from diagnostic biopsies (all patients).
• Blood samples collected at:
• Diagnosis (all patients)
• During neoadjuvant therapy (ECV2)
• After surgical resection of tumor (ECV2 and PC1)
• During adjuvant therapy (ECV2 and PC1)
• During follow-up (ECV2 and PC1)

Collaborating researchers and departments

Department of Clinical Genetics, Odense University Hospital and Research Unit of Human Genetics, Department of Clinical Research, University of Southern Denmark

• PhD-student Kristina Magaard Koldby, MSc
• Professor Torben A. Kruse, lic. scient, MSc
• Associate Professor Mads Thomassen, PhD, MSc

Department of Surgery, Odense University Hospital

• Professor Michael Bau Mortensen, DMSc, PhD, MD

Department of Pathology, Odense University Hospital

• Associate Professor Sönke Detlefsen, PhD, MD

Department of Oncology, Odense University Hospital

• Professor Per Pfeiffer, PhD, MD