Lobectomy Might Not Sufficient to Prevent Recurrence for Korean PTC (T1b) Patients According to the Korean Multicenter Study

Program: Abstracts - Orals, Poster Previews, and Posters
Session: SAT 270-310-Thyroid Neoplasia (posters)
Saturday, April 2, 2016: 1:15 PM-3:15 PM
Exhibit/Poster Hall (BCEC)

Poster Board SAT 296
Yul Hwangbo*1, Jung Min Kim2, Young Joo Park3, Do Joon Park3, Young Sik Choi4, Kang Dae Lee4, Eun Kyung Lee5, You Jin Lee5, Seo Young Sohn6, Sun Wook Kim7, Jae Hoon Chung7, Dong Jun Lim8, Min Hee Kim8, Min Joo Kim9, Young Suk Jo10, Minho Shong11, Sung-Soo Koong12, Jong Ryeal Hahm13, Jung Hwa Jung13 and Ka Hee Yi3
1National Cancer Center, Seoul, South Korea, 2Sanggye Paik Hospital, Inje University College of Medicine, 3Seoul National University College of Medicine, Seoul, South Korea, 4Kosin University College of Medicine, 5National Cancer Center, Goyang, South Korea, 6Myongji hospital, 7Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea, 8Seoul St. Mary’s Hospital, The Catholic University of Korea, College of Medicine, Seoul, South Korea, 9Korea Cancer Center Hospital, Seoul, South Korea, 10Yonsei University College of Medicine, Seoul, South Korea, 11Chungnam National University Hospital, Daejeon, South Korea, 12Chungbuk National University College of Medicine, Cheongju, South Korea, 13Gyeongsang National University School of Medicine, Jinju, South Korea
Context: In patients with papillary thyroid cancer (PTC), disease recurrence is a leading cause of morbidity and mortality. However, the risk factors associated with recurrence have not been established for small PTC.

Objective: The aim of the study was to evaluate the risk factors for recurrence in patients with PTC ≤2 cm (T1).

Design and Patients: We conducted a retrospective, nationwide multicenter study including 3282 patients with papillary thyroid tumors sized ≤2 cm (T1) from 9 high volume hospitals in Korea. The Kaplan-Meier analysis was used to estimate disease-free survivial, and the Cox proportional hazards regression model was used to analyze the risk factors for recurrence. Maximally selected chi-square method was used to find best cutoff points of tumor size and lymph node ratio to predict the recurrence.

Setting: The study was performed at 9 hospitals in Korea.

Results: Lymph node metastasis (N1a; HR, 4.15; 95% CI, 2.72-6.31; N1b; HR, 6.55; 95% CI, 3.98-10.77; P<0.001), lobectomy (HR, 2.93; 95% CI, 1.75-4.88; P<0.001) and tumor size >1cm (HR, 1.82; 95% CI, 1.26-2.64; P=0.002) were independent risk factors for recurrence in all PTC patients. In patients with total thyroidectomy, bilaterality (HR, 2.11; 95% CI, 1.18-3.78; P=0.012) was associated with more frequent disease recurrence, while radioactive iodine ablation was not related to less frequent disease recurrence. Size at 1.7cm was the most appropriate cut-off value capable of dividing PTC patients into two subgroups by recurrence distributions (5 year recurrence rate; 3.7% vs.9.4%). Lymph node ratio at 41% was optimal cutpoint to classify PTC patients with central neck dissection predicting the risk of recurrence (5 year recurrence rate; 1.2% vs. 10.9%).

Conclusion: Total thyroidectomy is recommended for small PTC patients to reduce recurrence.


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