Group that be scheduled to undergo chemothrapy only using FOLFOX4 protocol.

Group that not only be scheduled to undergo chemothrapy using FOLFOX4 protocol,but also receive colonscopy-assisted PDT.

Each patient to whom PDT was offered underwent a specific, detailed educational process by a dedicated team member(P.B., P.J., or K.E.), after which informed consent was obtained.Porfimer sodium (Photofrin; Axcan Pharma Inc, Quebec, Canada)was used as a photo sensitizing agent, administered intravenously at a dose of 2 mg/kg body weight 48 hours before illumination.A diode laser system (InGaAIP Laser Diode; Diomed Inc, An-dover, MA) with a maximum power output of 2000 mW and a wavelength of 633+-3 nm was used as a light source, delivered through a 3.0-m length fiber having a 2.5-cm-long cylindrical diffuser at its distal end (Pioneer Optics, Windsor Locks, CT).