研究发现，世贸中心从事救援和恢复工作的人员患某些癌症的风险较高，包括前列腺癌、甲状腺癌和骨髓瘤。尽管研究人员承认，需要更多的数据和更长的随访，但他们推测可能的原因是暴露于倒塌建筑物所释放出的致癌物质。

　　Jiehui Li（美国纽约市健康与心理卫生局）及其共同作者在JAMA杂志中写道，“考虑到随访时间相对较短，缺乏医学筛查和其它危险因素的数据，前列腺癌、甲状腺癌和多发性骨髓瘤发病率升高应该被重视。”

　　Li等人分析了2003到2004年世界贸易中心健康登记系统中55778名的相关信息。这是纽约州居民的观察性数据库，其中有21850位是2001年世界贸易中心被**之后的救援和恢复工作人员。在登记之后到2008年12月份，有1187例新诊断出的癌症，其中37%曾是世界贸易中心救援和恢复工作人员。

　　结合所有的癌症病例，世界贸易中心救援和恢复工作人员标准化发病比为1.14每10万人年，未参与救援和恢复工作人员的标准化发病比为0.92每10万人年，两者无统计学差异。然而，在研究的23个部位中，有3个部位的标准化发病比明显增加，前列腺（标准化发病比为1.43），甲状腺（标准化发病比为2.02），多发性骨髓瘤（标准化发病比为2.85）。对于世界贸易中心未参与救援和恢复工作人员，上述三个部位的标准化发病比未见增加。

　　研究者们注意到，高楼倒塌后使成百上千的人笼罩在灰尘、碎片、毁坏的建筑材料和潜在的毒物中。这些灰尘、烟雾和气溶胶包含了多种已知和未知的致癌物，包括石棉、硅、苯、多氯化联苯、多环芳烃、挥发性有机化合物和多种金属。然而，通过队列内比较，他们发现无论是参与救援和恢复工作人员还是未参与救援和恢复工作人员，暴露于世贸中心相关碎片的强度与特定部位的癌症无明显相关性。

　　研究者们写道，“暴露个体的剂量是否达到足以致癌的程度，以及过量的暴露能否通过现在的流行病学途径检测到目前仍处于争论中”。需要通过对参与救援和恢复工作人员和未参与救援和恢复工作人员进行更长期的随访以及对选定部位的癌症进行细致的观察，经过相当长的潜伏期来检测其癌症风险。

　　Association Between World Trade Center Exposure and Excess Cancer Risk

　　Jiehui Li, MBBS, MSc; James E. Cone, MD, MPH; Amy R. Kahn, MS; Robert M. Brackbill, PhD, MPH; Mark R. Farfel, ScD; Carolyn M. Greene, MD; James L. Hadler, MD, MPH; Leslie T. Stayner, PhD; Steven D. Stellman, PhD, MPH

　　Context The terrorist attacks of September 11, 2001, resulted in the release of known and suspected carcinogens into the environment. There is public concern that exposures may have resulted in increased cancers. Objective To evaluate cancer incidence among persons enrolled in the World Trade Center Health Registry. Design, Setting, and Participants Observational study of 55 778 New York State residents enrolled in the World Trade Center Health Registry in 2003-2004, including rescue/recovery workers (n = 21 850) and those not involved in rescue/recovery (n = 33 928), who were followed up from enrollment through December 31, 2008. Within-cohort comparisons using Cox proportional hazards models assessed the relationship between intensity of World Trade Center exposure and selected cancers. Main Outcome Measures Cases were identified through linkage with 11 state cancer registries. Standardized incidence ratios (SIRs) adjusted for age, race/ethnicity, and sex were computed with 2003-2008 New York State rates as the reference, focusing on cancers diagnosed in 2007-2008 as being most likely to be related to exposure during September 11 and its aftermath. The total and site-specific incidence rate differences (RDs) per 100 000 person-years between the study population and the New York State population in 2007-2008 also were calculated. Results There were 1187 incident cancers diagnosed, with an accumulated 253 269 person-years (439 cancers among rescue/recovery workers and 748 among those not involved in rescue/recovery). The SIR for all cancer sites combined in 2007-2008 was not significantly elevated (SIR, 1.14 [95% CI, 0.99 to 1.30]; RD, 67 [95% CI, ??6 to 126] per 100 000 person-years among rescue/recovery workers vs SIR, 0.92 [95% CI, 0.83 to 1.03]; RD, ??45 [95% CI, ??106 to 15] per 100 000 person-years among those not involved in rescue/recovery). Among rescue/recovery workers, the SIRs had significantly increased by 2007-2008 for 3 cancer sites and were 1.43 (95% CI, 1.11 to 1.82) for prostate cancer (n = 67; RD, 61 [95% CI, 20 to 91] per 100 000 person-years), 2.02 (95% CI, 1.07 to 3.45) for thyroid cancer (n = 13; RD, 16 [95% CI, 2 to 23] per 100 000 person-years), and 2.85 (95% CI, 1.15 to 5.88) for multiple myeloma (n = 7; RD, 11 [95% CI, 2 to 14] per 100 000 person-years). No increased incidence was observed in 2007-2008 among those not involved in rescue/recovery. Using within-cohort comparisons, the intensity of World Trade Center exposure was not significantly associated with cancer of the lung, prostate, thyroid, non-Hodgkin lymphoma, or hematological cancer in either group. Conclusions Among persons enrolled in the World Trade Center Health Registry, there was an excess risk for prostate cancer, thyroid cancer, and myeloma in 2007-2008 compared with that for New York State residents; however, these findings were based on a small number of events and multiple comparisons. No significant associations were observed with intensity of World Trade Center exposures. Longer follow-up for typically long-latency cancers and attention to specific cancer sites are needed.