Karlsson P, Holmberg E, Johansson K A, Kindblom L G, Carstensen J, Wallgren A
Department of Oncology, Sahlgrenska University Hospital, Göteborg, Sweden.
Radiother Oncol. 1996 Jan;38(1):25-31. doi: 10.1016/0167-8140(95)01663-5.
In a register study all women in the West of Sweden Health Care Region with a breast cancer diagnosed between 1960 and 1980 (n = 13,490) were followed up in the Swedish Cancer Register to the end of 1988 for later occurrence of a soft tissue sarcoma (STS). Nineteen sarcomas were reported, whereas 8.7 were expected and the relative risk (RR) was 2.2 (CI 95% 1.3-3.4). The absolute risk was 1.7/10(4) person years (PY) in comparison with 0.8 expected. To obtain a more detailed analysis of the associations between arm lymphoedema, radiotherapy and STS development, and to control the quality of the register data, a case control study was also performed. Clinical records from the different hospitals in the region were collected for all the 19 cases as well as for three selected controls per case. The histopathology of the cases were reviewed, and one of the cases was reclassified as a malignant melanoma and excluded from further analysis. Thirteen of the cases were clustered around the treated breast area. To quantify the exposure to radiotherapy, the integral dose was estimated. The presence of lymphedema was included as a binary variable in the analysis. The exact conditional randomisation test indicated a significant correlation between the integral dose and the development of an STS (p = 0.008) and this association was still significant after stratification for arm oedema. A conditional logistic regression analysis with STS as the dependent variable and the integral dose as the explanatory variable gave an odds ratio (OR) of 5.2/100 J (CI 95% 1.3-21.2), and if this regression was restricted only to the STS developing in the radiation fields the OR was 3.2/100 J (CI 95% 0.8-12.9). Thus, the excess of STS in this breast cancer cohort was very low (0.9/10(4) PY). However the integral dose correlates well to the development of STS and can be useful in quantifying even small risks of secondary malignancies in the breast cancer population.
在一项登记研究中，对瑞典西部医疗保健地区1960年至1980年间被诊断为乳腺癌的所有女性（n = 13490）进行了随访，直至1988年底，以观察软组织肉瘤（STS）的后续发生情况。报告了19例肉瘤，而预期为8.7例，相对风险（RR）为2.2（95%可信区间1.3 - 3.4）。绝对风险为1.7/10⁴人年（PY），而预期为0.8。为了更详细地分析手臂淋巴水肿、放疗与STS发生之间的关联，并控制登记数据的质量，还进行了一项病例对照研究。收集了该地区不同医院的临床记录，包括所有19例病例以及每例病例的3名选定对照。对病例的组织病理学进行了复查，其中1例病例被重新分类为恶性黑色素瘤并被排除在进一步分析之外。13例病例聚集在接受治疗的乳房区域周围。为了量化放疗暴露情况，估计了积分剂量。淋巴水肿的存在作为二元变量纳入分析。精确条件随机化检验表明积分剂量与STS的发生之间存在显著相关性（p = 0.008），并且在按手臂水肿分层后这种关联仍然显著。以STS为因变量、积分剂量为解释变量的条件逻辑回归分析得出比值比（OR）为5.2/100 J（95%可信区间1.3 - 21.2），如果该回归仅限于在放射野中发生的STS，则OR为3.2/100 J（95%可信区间0.8 - 12.9）。因此，该乳腺癌队列中STS的超额发生率非常低（0.9/10⁴ PY）。然而，积分剂量与STS的发生密切相关，可用于量化乳腺癌人群中即使很小的继发性恶性肿瘤风险。
