霍奇金淋巴瘤幸存者面临高乳腺癌风险

芝加哥(EGMN)—— 纽约纪念斯隆-凯特琳肿瘤中心的生物统计师Chaya S. Moskowitz博士在美国临床肿瘤学会(ASCO)年会上报告，儿童时期接受霍奇金淋巴瘤胸部放疗的女性患者乳腺癌风险远远高于以往公认水平。

多项研究提示，儿童时期接受胸部放疗的女性乳腺癌风险增高。为了更好地阐述这部分患者的乳腺癌风险，Moskowitz博士及其同事进行了这项研究。

这项来自儿童肿瘤幸存者研究(CCSS)和女性环境致癌和辐射流行病学(WECARE)研究的分析，利用了1970~1986年间被诊断为儿童肿瘤的1,268例女性幸存者和被诊断乳腺癌后存活至少1年的女性患者的4,570名一级亲属的数据。儿童肿瘤幸存者的中位随访时间为26年。

结果显示，其中175例女性幸存者在成年后被诊断为乳腺癌。治疗后的中位潜伏期为23年，诊断时的中位年龄为38岁。Moskowitz博士说，幸存者在50岁前的乳腺癌发病率为30%——与携带BRCA1基因突变的高危女性的发病率31%惊人相似。儿童时期因肿瘤接受胸部放疗的幸存患者的累积风险也显著增高，在50岁时达到24%，而在美国一般女性群体中，这一比例仅为4%。接受≥20 Gy胸部放疗的患者中，12%的幸存者在40岁时发生乳腺癌。对于这部分患者，应从25岁或放疗后8年开始，每年进行胸部X线检查。

这项研究还显示，在接受10~19 Gy放疗的幸存者中，乳腺癌发病率也增高，但幅度较小，40岁时为7%。研究者认为，对于这部分患者，也应考虑采取与放疗剂量≥20 Gy者相似的乳腺癌监测策略。

研究者披露无相关利益冲突。

爱思唯尔  版权所有

BY JANE SALODOF MACNEIL
Elsevier Global Medical News
Breaking News

CHICAGO (EGMN) –Breast cancer risk is much higher than previously recognized among women who received chest radiation for Hodgkin’s lymphoma when they were children, investigators reported.

By the time these survivors are 50 years of age, breast cancer incidence is 30% – “remarkably similar” to the 31% incidence observed in the high-risk group of women with BRCA1 mutations, Chaya S. Moskowitz, Ph.D., and her colleagues determined in a study presented at the annual meeting of the American Society of Clinical Oncology.

Although the effect was less dramatic, cumulative risk also was elevated in survivors of other childhood cancers treated with chest radiation, reaching 24% overall by age 50, Dr. Moskowitz said at a press briefing. Among the general population of women in the United States, it is 4% at that benchmark, she noted.

Particularly concerning is the heightened risk observed in women who received less radiation than the current threshold at which the Children’s Oncology Group (COG) recommends breast cancer surveillance. The COG says that survivors who received 20 Gy or more of chest radiation should start annual mammograms at age 25 years or 8 years after radiotherapy, whichever comes later.

In this group, 12% of survivors will develop breast cancer by age 40, said Dr. Moskowitz, a biostatistician at Memorial Sloan-Kettering Cancer Center in New York. The study showed that breast cancer incidence also was elevated, albeit not as dramatically – 7% by age 40 – among survivors who received 10-19 Gy of radiation.

Excess risk in those treated with 10-19 Gy warrants “consideration of breast cancer surveillance strategies similar to the current recommendations for women treated with [more than] 20 Gy,” the investigators concluded.

About 50,000 survivors received 20 Gy or more of radiation and, therefore, meet the current threshold, Dr. Moskowitz said. Lowering the threshold to include survivors who were treated with 10-19 Gy of chest radiation would add another 7,000-9,000 women.

Increasing public awareness is crucial to increasing surveillance. “Many women who were treated with chest radiation don’t know they have an increased risk of breast cancer,” she said. “Their physicians may or may not know, but many physicians are not aware of the guidelines.”

Moreover, many survivors don’t know their radiation exposure, and she urged them to try to find those records from long, long ago.

The analysis – a report from the Childhood Cancer Survivor Study (CCSS) and the Women’s Environmental Cancer and Radiation Epidemiology (WECARE) study – mined data on 1,268 women survivors of childhood cancers diagnosed from 1970 to 1986 and on 4,570 first-degree relatives of women who had survived at least 1 year after being diagnosed with breast cancer.

Median follow-up was 26 years in the childhood survivors, of whom 175 women were diagnosed with breast cancer as adults. Median latency was 23 years after treatment, and diagnosis was made at a median age of 38 years.

Multiple studies have shown an increased risk of breast cancer in women who received chest radiation as children, Dr. Moskowitz said. This large study has substantially longer follow-up and was surprising in the magnitude of risk it documents.

Chest radiation doses are lower today, and mantle field radiation – which had been used almost exclusively in Hodgkin’s lymphoma – is no longer used, but other regimens are still in the clinic, she added.

Another surprise from the study was that whole lung radiation, even at low doses, can heighten breast cancer risk. “Women treated with whole lung radiation have a risk of breast cancer that is higher than previous recognized and may benefit from surveillance strategies,” she said.

“These are striking data and certainly warrant our careful attention,” commented press briefing chair Dr. Nicholas Vogelzang, chair and medical director of the developmental therapeutics committee at the Comprehensive Cancer Centers of Nevada, Las Vegas, and cochair of the genitourinary committee for U.S. Oncology Research.

“The benefit of curing a cancer is you can live 25 or more years,” he said, noting that curves for breast cancer incidence rose after 25 years in a graphic representation of the data presented. “We have an obligation to those many thousands of young women whom we treated many years ago.”

The investigators said that they had no relevant financial disclosures.