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Vol.61 No.4 contents | Japanese/English |
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- Original Article -
Correlation Between the Tumor Doubling Time and Histologic Subtypes in Thymic Epithelial Tumors: Is It Possible to Differentiate Between Thymoma and Thymic Carcinoma?
Koichi Fukumoto1, Madoka Goto1, Yasuhisa Ichikawa1, Yuta Kawasumi1, Mika Uchiyama1, Shoichi Mori11Department of Thoracic Surgery, Japanese Red Cross Nagoya Daiichi Hospital, Japan
Objective. We assessed the utility of the tumor doubling time (TDT) for predicting the histological type of thymic epithelial tumors. Methods. We retrospectively reviewed 67 patients with thymic epithelial tumors who underwent surgery in our institution. Patients who underwent induction therapy or who failed to undergo serial computed tomography (CT) at least twice before surgery with an interval exceeding 20 days were excluded. The relationship between the histological type and the TDT was ultimately investigated in 38 patients. Results. The study population consisted of 16 men and 22 women (median age, 65 years old). The median preoperative tumor size was 4.0 cm. Twenty-nine tumors were diagnosed as thymoma, and 9 were diagnosed as thymic carcinoma. The median interval of the serial CT studies was 113 days. During the follow-up period, 29 patients showed an increase in tumor size (thymoma, n=20; thymic carcinoma, n=9). Tumor regression was observed in 1 patient (thymoma, n=1), while 8 patients showed no marked change in tumor size (thymoma, n=8). In 29 patients who showed tumor enlargement, the TDT in thymic carcinoma (median 164 days; range 44-2130 days) was significantly shorter than that of thymoma (median 468 days; range 138-4519 days) (p=0.0072). The area under the curve (AUC) of the receiver operating characteristic (ROC) curve for the differential diagnosis between thymoma and thymic carcinoma was 0.817. Conclusion. The TDT can be a useful parameter for differentiating between thymoma and thymic carcinoma.
key words: Thymic epithelial tumor, Thymoma, Thymic carcinoma, Tumor doubling time, Histologic type
Received: February 2, 2021
Accepted: April 21, 2021
JJLC 61 (4): 297-302, 2021
