Presence of Circulating Tumor DNA in Colorectal Cancer
Condition: Colorectal Neoplasms
MeSH terms: Colorectal Neoplasms
Study type: Observational

Summary: 
      Cancer is a DNA disease characterized by the presence of genetics alterations in cancer
      cells.

      The recent studies underline that these recurring alterations must be considered as a good
      molecular marker. In fact, they could use for tumor DNA detection in different biological
      fluids.

      So, the main purpose is to define the presence of circulating tumor DNA in the patients
      plasma with colorectal cancer, by the presence of mutation (KRAS, NRAS, BRAF, APC, TP53 and
      MIRCOSATELLIE instability).

      These molecular analysis will be done both in tumor and plasma samples,

      This trial allows to characterize the prognostic value of circulating tumoral DNA presence in
      colorectal cancer.
    

Detailed description: 
      Two major issues appear in improving the prognosis of cancer patients, the first is early
      detection and the second is the risk of recurrence or the early diagnosis of recurrence in
      order to propose the most appropriate treatment for patients.

      Cancer is a DNA disease that is characterized by the acquisition by the tumor cell during
      carcinogenesis of a number of recurrent genetic alterations. The development of molecular
      tools that can easily characterize these abnormalities specific to tumor cells, allows us to
      consider their use in clinical practice. These genetic alterations could represent useful
      molecular markers for detecting the presence of tumor DNA in various biological fluids
      including plasma of cancer patients. This circulating tumor DNA, whose nature is confirmed by
      the similarity of genetic alterations with those observed from DNA extracted from tumor cells
      of the patients, represents a molecular marker of cancer available from a single sample and
      could be an alternative to the use of more conventional markers such as CEA. We propose in
      this study to confirm the predictive value on the risk of recurrence or metastasis of
      circulating tumor DNA in plasma of patients with colorectal cancer from a cohort study (250
      patients with non-metastatic colorectal cancer (Stage II and III). This is a multicenter
      prospective study. The cohort of patients will be followed for a minimum period of 36 months.
      A biological analysis of the tumor in search for the main genetic alterations of colorectal
      cancer cells will be made (KRAS, NRAS, TP53, BRAF and APC mutations as well as the presence
      of a microsatellite instability). These same genetic alterations will be sought on a plasma
      sample taken before surgery and during follow-up (9 samples in total). The objectives of this
      study will be 1/to assess the prognostic value of the presence of circulating tumor DNA in
      plasma, by searching for an association between the risk of and the presence of genetic
      alteration in the plasma of these patients, 2/to search for a relationship between initial
      rate of circulating tumor DNA and the risk of local recurrence,3/ to characterize the
      relationship between the type of alterations in the plasma at the initial diagnosis of
      circulating tumor DNA and the risk of recurrence 4/ to assess during the follow-up the
      prognostic value of the occurrence of tumor circulating DNA.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        defined population : patients suffer from colorectal cancers in stage II-III
      
Biospecimen description: 
      serum and tissue
    
Keywords: Genetics modifications; colorectal cancer; prognosis aim; DNA; Plasma