大腸直腸癌在美國為癌症死因的第二位，對病人日後的生活品質往往造成很大的影響，它大多發生在年紀大於六十五歲的病人身上,而我們的人口正在老化當中，老化會使各種組織對癌化的感受性增加並加速癌化的進展及惡化，然而大約有20%左右的病人具有家族聚集及一等親罹癌或有大腸良性腺癌的病史，這類族群的患者通常年紀較輕且可能具有不同的基因型表現。大腸直腸癌年輕病患和年老病患的預後到底是否相同目前仍有爭議，我們以五十歲做為區分年輕和年老族群的分界點，利用美國國家癌症研究院的「流行病監測及最終結果/SEER」資料庫來對年輕及年老族群的大腸癌做存活分析，收集自西元1995年至2008年被診斷為大腸癌且其病理診斷為惡性腺癌的病患共261523位，其中129969(49.7%)位為男性，131554(50.3%)位為女性，追蹤中位數時間為32個月，計算各個期別中位數存活時間及5年存活率並做比較，其中年老族群(>50歲)佔91.7%，年輕族群(<=50歲)佔8.3%，年老族群得到大腸癌的機率比起年輕族群高9倍，年老族群的平均年齡為72.50歲，年輕族群的平均年齡為43.74歲，性別在這兩個族群上對於是否會得到大腸癌都沒有差異，年老族群的大腸癌通常以右側結腸癌居多。相較於年輕乳癌患者的診斷時期別通常在末期且存活率較低，年輕族群大腸癌的患者其存活率在各個期別都比年老族群高，推測可能是因有較少的共病及較好的身體狀況足以面對癌症的各種治療所致。

Colorectal cancer is the second leading cause of cancer death in the United States and is an important contributor to cancer morbidity. The majority of patients with colorectal cancer (CRC) are older than 65 years, and our population is aging. Aging may increase the susceptibility of various tissues to initiation of carcinogenesis and facilitates promotion and progression of carcinogenesis. However, about 20% of patients of colorectal cancer are associated with familial clustering and first-degree relatives of patients with colorectal adenomas or invasive colorectal cancer are at risk for colorectal cancer. This group of patients are general younger and may have different genomic expression. Whether the prognosis of young age and old age in colon cancer are the same is still debated. We used Surveillance, Epidemiology, and End Results Program (SEER) database to study survival difference between young age and old age of colon cancer. Patients diagnosed with colon cancer from the SEER database (1995-2008) were analyzed. Only adenocarcinoma was included. A total of 261,523 patients with a median follow-up of 32 months were included. The cutoff point of age is 50 years. Median survival and 5-year survival rate of patients with the same stage of young and old group were evaluated. The colon cancer study group included 129,969 men (49.7%) and 131,554 women (50.3%). Of the 261,523 patients with colon cancer, 91.7% are old age and 8.3% are young age. The colon cancer incidence of old age was 9 times greater than the young age incidence. Mean age of the older group patients was 72.5 years and 43.74 years for young group. The gender ratio among colon cancer in young group was similar with old group. The right site tumors are more common in old group. Unlike women with breast cancer that young women generally face more aggressive stages and lower survival rates, patients diagnosed with colon cancer of young group have better survival than old group in all stages possible due to less comorbidities and better tolerance to treatment.

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