Risk Of Recurrence Stage I And II Colorectal Cancer
Overview of Stage I and II Colorectal Cancer
Stage I colorectal cancer is confined to the submucosa or up to the muscularis propria but has not gone beyond. Stage II colorectal cancer is in the muscularis propria or beyond but has not invaded the lymph nodes or metastasized. Current guidelines are post-surgical removal of the cancer and indicate surgery alone is sufficient for Stage I; but, the guidelines give the physician the option of observation or adjuvant chemotherapy for cancer at Stage II. Approximately 25% of all colorectal cancer is at Stage II.
Risk of Reoccurrence
Approximately 1 in 7 cases of Stage I Colorectal cancer will reoccur. Of the cases that reoccur over 50% will die of the disease. For Stage II, approximately 1 in 3 cases will reoccur. Of those cases that reoccur over 80% will prove fatal. The type of tumor in Stage II colon cancer did have a predictive value for recurrence.
Tumor microRNA-29a Expression and Colon Cancer
A study published March of 2012 evaluated the prognostic value of microRNA in Stage I and Stage II tumors. The patients had undergone surgery to remove the colon cancer between 1995 and 2005 and the patients had not received adjuvant therapy. The data was analyzed for patients who did and did not have recurrence of cancer within 36 months of surgery.
For Stage I tumor patients, the microRNA profile did not make a difference in a good versus a poor prognosis. However, there was a notable difference for the patients who had Type II tumors and who had microRNA-29a in the tumor. High expression of microRNA-29a was associated with longer disease-free survival. Using microRNA-29a the positive predictive value for non-recurrence was 94%.
Lymphocyte Infiltration of the Tumor in Colorectal Cancer
Studies have shown the density of T cells near the tumor cells in the primary tumor is an excellent predictor of survival. In particular one study showed patients whose tumors contained large numbers of CD3-positive T cells had a 5 year survival rate of 73% compared to 30% of the patients with a low density of these T cells.
Differentiating Between Those at Increased Risk and Those Not: Colon Cancer
According to the National Cancer Institute, “features in patients with stage II colon cancer that are associated with an increased risk of recurrence include inadequate lymph node sampling, T4 tumor disease, involvement of the visceral peritoneum, and a poorly differentiated histology.”
T4 tumors extend through the colon wall and attach to or invade a nearby organ. It is recommended that at least 12 lymph nodes be sampled. Other factors increasing the risk are if the cancer exhibited microsatellite instability, the cancer was in or near the margin of the surgical specimen (a possible indication that some of the cancer may have been left behind) and the cancer blocking off the colon or perforating the colon. Microsatellite instability has to do with the instability or errors in the microsatellite DNA of tumors.
Those with Increased Risk Recurrence: Rectal Cancer
A study looking at the key factors for recurrence of rectal cancer found recurrence occurred usually within 3 years. The location of the initial tumor was found to be important. But the key factors were found to be “early resection and a wide tumor-free resection margin.”
Adjuvant Chemotherapy for Colon Cancer
5-fluorouracil (5-FU) alone or in combination with other chemotherapy is a common regimen for adjuvant chemotherapy. However, since 2000, capecitabine has been established as an equivalent alternative to 5-FU and leucovorin. The addition of oxaliplatin to 5-FU and leucovorin has been shown to improve overall survival as compared to 5-FU and leucovorin alone. Additionally, since 2011, bevacizumab (Avastin) used with other chemotherapy has been shown through clinical studies to lead to increased risks of side effects that may lead to death.
Adjuvant Immunotherapy for Colon Cancer
Active Specific Immunotherapy (ASI) using Oncovax (irradiated autologous tumor cells mixed with BCG) was studied in multiple clinical trials. When Oncovax was used, there was a 34% annual reduction in recurrence of cancer. Disease-specific survival was improved with patients that received 4 doses of the vaccine. Virtually no toxicity was observed.
Adjuvant Therapy for Rectal Cancer
Patients with Stage II rectal cancers can also benefit from radiation therapy, in addition to surgery, to minimize local recurrence. Along with mesorectal incision, these two interventions have been shown to reduce the recurrence rate of as high as 40% to as low as 5%.