Does age influence the outlook of colorectal cancer?

The authors aimed to evaluate the association between age and survival outlook after surgery in colorectal cancer.

Generally, colorectal cancer is thought to affect mostly older people, with more than 90% of patients being diagnosed after age 55 years. However, despite there being a steady decline of colorectal cancer incidence, the rate of colorectal cancer in younger people appears to be increasing. Colorectal cancer in younger patients is generally found to have a poorer outlook than in the elderly, but this is still widely debated.

The authors aimed to analyse the role of age on colorectal long-term survival after surgery. The authors identified 69,835 patients with stage I to III colorectal cancer who had undergone surgery to remove the cancer. The younger age group was defined as ≤40 years of age (3,014 patients), while the elderly group was defined as >40 years of age (66,821 patients). Patients in the younger age group had a slightly higher percentage of stage III cancer and also a higher percentage of more aggressive cancer types. The average follow-up time was 97 months.

The 5-year colorectal cancer-specific survival was 78.6% in the younger age group compared to 75.3% in the elderly group. Women were found to have a 13% reduced risk of poor survival outcomes. Compared to colon cancer, rectal cancer was associated with a 10% increased risk. The risk was also increased by 7.5% for mucinous cancer (arises from cells that produce mucus) and by 71.6% for signet-ring cancer (a rare, aggressive form of colorectal cancer) compared to adenocarcinoma (the most common form of colon cancer).

Compared to stage I cancer, stage II cancer had 2.9 times the risk of poor survival outcomes, while stage III cancer had 4.8 times the risk. Having more lymph node involvement at the time of surgery was also linked to a higher risk of poor survival outcomes. 

The authors concluded that though the younger age group typically presented with worse cancer characteristics, this did not translate into poorer survival outcomes.

The article did not discuss the impact of other forms of cancer therapy given in addition to surgery (such as chemotherapy, biological therapy).