Department of Surgery, The University of Hong Kong, Hong Kong, China.
Surgery. 2012 Jun;151(6):844-50. doi: 10.1016/j.surg.2011.12.019. Epub 2012 Feb 15.
Differentiated thyroid cancer survivors are at increased risk of nonsynchronous second primary malignancy, but the cause remains unclear. This study aimed to evaluate the association between radioiodine therapy and risk of nonsynchronous second primary malignancy and to examine whether the risk of nonsynchronous second primary malignancy in differentiated thyroid cancer survivors treated with radioiodine therapy is increased relative to the general population.
Among 895 radiation-naïve patients with differentiated thyroid cancer, 643 (71.8%) received ≥1 course of radioiodine therapy (radioiodine therapy-positive group) and 252 (28.2%) received no radioiodine therapy (radioiodine therapy-negative group). After a median follow-up of 93.5 months (range, 23.4-570.8), 64 (7.2%) patients developed ≥1 nonsynchronous second primary malignancy. Potential risk factors for nonsynchronous second primary malignancy were entered into a multivariable regression model and cancer incidence in the radioiodine therapy-positive and -negative groups were compared to that of the general population by estimating the standardized incidence ratios.
The 20-year cumulative nonsynchronous second primary malignancy risk in radioiodine therapy-positive group was significantly higher than radioiodine therapy-negative group (13.5% vs 3.1%; P = .015). Cumulative radioiodine therapy activity of 3.0 to 8.9 GBq (relative risk, 2.77; 95% CI, 1.079-7.154; P = .034) was the only independent risk factor for nonsynchronous second primary malignancy after adjusting for age, sex, period of differentiated thyroid cancer diagnosis, and stage of differentiated thyroid cancer. For females, the standardized incidence ratio in the radioiodine therapy-positive group was 1.54 (95% CI, 1.11-2.08) and in the radioiodine therapy-negative group it was 0.92 (95% CI, 0.37-1.90).
Differentiated thyroid cancer female survivors treated by radioiodine therapy appeared to be at elevated risk of nonsynchronous second primary malignancy when compared to the general population and this risk was not apparent in those not previously treated by radioiodine therapy.
分化型甲状腺癌幸存者发生非同步第二原发恶性肿瘤的风险增加，但病因仍不清楚。本研究旨在评估放射性碘治疗与非同步第二原发恶性肿瘤风险之间的关系，并探讨放射性碘治疗是否会增加分化型甲状腺癌幸存者发生非同步第二原发恶性肿瘤的风险。
在 895 例未经放射性碘治疗的分化型甲状腺癌患者中，643 例（71.8%）接受了≥1 次放射性碘治疗（放射性碘治疗阳性组），252 例（28.2%）未接受放射性碘治疗（放射性碘治疗阴性组）。中位随访 93.5 个月（范围：23.4-570.8）后，64 例（7.2%）患者发生了≥1 例非同步第二原发恶性肿瘤。将潜在的非同步第二原发恶性肿瘤危险因素纳入多变量回归模型，并通过估计标准化发病比比较放射性碘治疗阳性和阴性组与一般人群的癌症发病率。
放射性碘治疗阳性组 20 年非同步第二原发恶性肿瘤累积风险显著高于放射性碘治疗阴性组（13.5% vs. 3.1%；P=.015）。在调整年龄、性别、分化型甲状腺癌诊断时期和分化型甲状腺癌分期后，放射性碘治疗活度为 3.0 至 8.9GBq（相对风险，2.77；95%CI，1.079-7.154；P=.034）是唯一的非同步第二原发恶性肿瘤独立危险因素。对于女性，放射性碘治疗阳性组的标准化发病比为 1.54（95%CI，1.11-2.08），放射性碘治疗阴性组为 0.92（95%CI，0.37-1.90）。
与一般人群相比，接受放射性碘治疗的分化型甲状腺癌女性幸存者发生非同步第二原发恶性肿瘤的风险似乎升高，而未接受放射性碘治疗的患者则无此风险。
