UPMC Cancer Pavilion, University of Pittsburgh, Pittsburgh, PA 15232, USA.
Int J Oncol. 2010 Oct;37(4):901-7. doi: 10.3892/ijo_00000741.
Medullary carcinoma (MC) of the colorectum is a relatively new histological type of adenocarcinoma characterized by poor glandular differentiation and intraepithelial lymphocytic infiltrate. To date, there has been no epidemiological study of this rare tumor type, which has now been incorporated as a separate entity in the World Health Organization (WHO) classification of colorectal cancers. We used the population-based registries of the Surveillance, Epidemiology and End Results (SEER) database to identify all cases of colorectal MC between 1973 and 2006 and compared them to poorly and undifferentiated colonic adenocarcinomas (PDA and UDA, respectively). We observed that MCs were rare tumors, constituting approximately 5-8 cases for every 10,000 colon cancers diagnosed, with a mean annual incidence of 3.47 (+/-0.75) per 10 million population. Mean age at diagnosis was 69.3 (+/-12.5) years, with incidence increasing with age. MCs were twice as common in females, who presented at a later age, with a lower stage and a trend towards favorable prognosis. MCs were extremely rare among African-Americans. MCs were most common in the proximal colon (74%), where they present at a later age than the sigmoid colon. There were no cases reliably identified in the rectum or appendix. Serum carcinoembryonic antigen levels (CEA) were elevated prior to first course of treatment in 40% of the patients. MCs were more commonly poorly differentiated (72%), with 22% being undifferentiated. MCs commonly presented with Stage II disease, with 10% presenting with metastases. Only one patient presented with N2b disease (>7 positive nodes). Early outcome analyses showed that MCs have 1- and 2-year relative survival rates of 92.7 and 73.8% respectively. Although MCs showed a trend towards better early overall survival, undifferentiated MCs present more commonly with Stage III, with comparatively worse early outcomes.
结直肠髓样癌（MC）是一种相对较新的腺癌组织学类型，其特征为腺体分化不良和上皮内淋巴细胞浸润。迄今为止，尚无针对这种罕见肿瘤类型的流行病学研究，目前它已被纳入世界卫生组织（WHO）结直肠癌分类的一个独立实体。我们使用基于人群的监测、流行病学和最终结果（SEER）数据库，确定了 1973 年至 2006 年间所有结直肠 MC 病例，并将其与分化不良和未分化的结肠腺癌（PDA 和 UDA）进行了比较。我们发现 MC 是罕见的肿瘤，每 10000 例结肠癌中约有 5-8 例，年发病率为每 100 万人口 3.47（+/-0.75）。诊断时的平均年龄为 69.3（+/-12.5）岁，发病率随年龄增长而增加。女性 MC 是男性的两倍，发病年龄较大，分期较低，预后较好。非洲裔美国人中 MC 非常罕见。MC 最常见于近端结肠（74%），其发病年龄晚于乙状结肠。直肠或阑尾未发现可靠病例。40%的患者在首次治疗前血清癌胚抗原（CEA）水平升高。MC 通常分化不良（72%），22%未分化。MC 常见于 II 期疾病，10%存在转移。只有 1 例患者出现 N2b 期疾病（>7 个阳性淋巴结）。早期结果分析表明，MC 的 1 年和 2 年相对生存率分别为 92.7%和 73.8%。尽管 MC 有早期总生存较好的趋势，但未分化的 MC 更常见于 III 期，早期结局较差。
