Can biology of the cancer predict survival?

This study investigated whether the biology of the cancer called mucinous histology can be used to predict the outcomes of patients with colorectal cancer. The study also evaluated the association between mucinous adenocarcinoma and microsatellite instability.

Mucinous histology (MH) is a microscopic observation of tissues to assess the presence of mucin (the main component of mucus). MH investigates mucinous adenocarcinoma (MA) and mucinous component (MC) in tumors. Adenocarcinomas (cancers that begin in the glandular cells) that are comprised of at least 50% mucus are referred to as MA. MC tumors have less mucus. Microsatellite instability (MSI) is a change that occurs in the DNA of certain cells (such as tumor cells) which cannot be normally repaired. MSI is a sign that certain genes are not functioning normally. Previous studies have shown that the presence of mucus (mucin) makes cancer cells more aggressive than cancers that do not contain mucus. Also, some studies have associated MA with MSI. This study aimed to evaluate this association and to determine whether MH can predict the outcomes of patients with colorectal cancer.

This study included a total of 394 colorectal cancer patients who have been treated with surgery to remove all the cancer and with 12 cycles of chemotherapy for 6 months. 89.6% of these patients had non-mucinous adenocarcinoma (NMA), while 10.4% of patients had either MA or MC (the MA/MC group). 6.6% of all patients had MSI tumors. Patients with MA/MC tended to have more advanced tumors compared to patients with NMA (39.0% of patients with MA/MC were diagnosed with stage III cancer compared with 18.1% patients with NMA). Also, MSI was more common in patients with MA/MC than in patients with NMA (17.1% versus 5.4%).

After approximately 3 years of follow up, disease recurrence (return of the cancer) occurred in 19.0% of patients with NMA compared to 36.6% in the MA/MC group. Patients with MA/MC tended to develop recurrence in the peritoneum (a sheath that covers the abdominal organs) more frequently than NMA patients (33% versus 25%). Disease free survival (defined as the percentage of patients who survive without any signs of the cancer a certain period after the treatment) 3 years after treatment was 79.2% in patients with NMA compared to 56.9% in patients with MA/MC. Also, in patients with MA/MC, there was no difference in disease free survival between patients with MSI and those without MSI.

This study concluded that mucinous histology can be used to predict disease progression and survival, independently of the MSI status of the tumor. Presence of mucin in tumors is a poor indicator of cancer status. These results can help medical practitioners chose more aggressive treatments for patients with this type of colorectal cancer.

This study analyzed clinical records in a hospital. The results may be biased because the accuracy of the pathologists involved could not be determined.

Talk to your doctor about the histological type of your cancer and which treatments are appropriate in your situation.