Microscopic and macroscopic liver tumor dimensions assessed with pathology and MRI studies to establish safety margins for stereotactic body radiation therapy: a pilot study.

Colorectal cancer is one of the most prevalent cancers and leading cause of
cancer mortality worldwide. As many as 50-70% of patients diagnosed of
colorectal cancer will present liver involvement during follow-up, being the
only site of recurrence in half of these patients. Surgery is accepted as a
potentially curative option with survival rates at 5 years of 25-35% for liver
metastases when disease is confined to the liver. However, the majority of
patients are not eligible for surgery because of diminished liver function
capacity after several resections or concomitant medical diseases. For patients
who are not suitable for surgery, other local treatment methods, especially
radiofrequency ablation (RFA) are emerging as alternative curative options but,
proximity of the lesion to the gallbladder or the main vessels constitute major
problems to apply this treatment. Radiotherapy has become a potential new
treatment option for primary and metastatic liver tumors around the world.

- To measure the microscopic infiltration depth around colorectal liver
metastases.
- To correlate pathologic macroscopic/microscopic tumor dimensions with MR
imaging findings.

This will be a prospective cohort pilot study. In total 40 colorectal liver
metastases will be included: 20 specimens treated preoperatively with
chemotherapy and 20 not. The estimation to complete the study is half a year.

The burden associated with participation is the burden associated with the
acquirement of a MRI scan with intravenous contrast agent administration. The
total scan will take 60 - 90 minutes to obtain. The subjects who will be asked
for their participation will not benefit from the results of this study unless
they will become eligible for stereotactic body radiation therapy in the
future. The study however can only be done with the cooperation of this patient
group.