Colorectal CA Chemo for a year?

My mother was dx with CA in Aug 2007.  She had a cecum resection that removed the ascending colon and 6 in of the small intestine.  There was a tumor in colon that had attached to the abdominal wall.  She also had a nodal in the shoulder area (lymph) removed that was malignant.  She has elevated CEA and CA19-9.  Her oncologist started her on chemo 5 weeks after surgery.  She had 6 treatments and then he repeated her PET/CT He is continuing her on chemo for another year?  Is this the norm?  

Her PET/CT Impression came back with:  No abn activity in the head and neck or chest.  Abn uptake corresponding to retroperitoneal adenopathy in L para aortic margin just below the l renal inferior pole measuring app 8.1 SUV  This is the same that was demonstrated on previous CT of 8/31/2007.  No additional areas of abnormal uptake are seen within the abdomen and pelvis.  Physiologic activity is noted.

[Fernando Roque, MD]

Hi.  Some types of chemotherapy for colorectal cancer, such as fluorouracil-leucovorin and FOLFOX regimens, as well as biologic agents like bevacizumab and cetuximab, are substantially less toxic and well-tolerated by patients.  So the current thinking about the use of these drugs is to continue using them beyond the usual six cycles, for as long as the tumor continues to respond to the chemo, and the patient is able to tolerate the additional doses.