This will be a prospective single arm biomarker (plasma-free DNA 5-hydroxymethylation)
study. Fifty-five Adult patients with peritoneal metastases of colorectal and appendiceal
origin who are candidates for a curative surgery and fulfill the inclusion criteria will
be offered to participate in this study. In addition to the postoperative standard of
care oncological surveillance of these patients which includes periodic physical
examinations, cross sectional imaging studies (CT or MRI) and blood work for conventional
tumor markers, serial measurements of plasma hydroxymethylation signatures will be
performed. We will use a model developed in a separate pilot study to identify recurrent
peritoneal metastasis based on 5hmC signatures. As part of this study, blood collection
for measurements of plasma hydroxymethylation signatures of target genes will be
performed at seven time points:
- Just before surgery (During the preoperative clinic visit or at the operating room).
- 5-7 days after surgery (just before hospital discharge).
- 6 weeks after surgery (first postoperative clinic visit).
- 3 months after surgery (second postoperative clinic visit).
- 6 months after surgery (third postoperative clinic visit).
- 9 months after surgery (fourth postoperative clinic visit).
- 12 months after surgery (fifth postoperative clinic visit). Standard of care
surveillance elements that include patient history and physical examination,
conventional blood biomarkers (CEA, CA 19-9 and CA 125) and cross sectional imaging
of the chest, abdomen and pelvis will be undertaken simultaneously at similar time
points. We will then compare the sensitivities of DNA hydroxymethylation signatures
and conventional blood biomarkers in diagnosing clinically detectable recurrence at
1 year after surgery. We hypothesize that plasma hydroxymethylation signatures have
higher sensitivity in identifying clinically detectable recurrence when compared
with conventional tumor markers (CEA, CA 19-9 and CA 125).
