Is Thymomectomy Alone Appropriate for Stage I (T1N0M0) Thymoma? Results of a Propensity-Score Analysis.
BACKGROUND
The optimal mode of resection for thymoma in nonmyasthenic patients remains unclear. The aim of this study was to explore whether or not thymomectomy alone is a relevant option for patients with stage I (T1N0M0) thymoma in the proposed TNM classification.


METHODS
We investigated 2,835 patients with thymic epithelial tumors treated at 32 institutions participating in the Japanese Association for Research on the Thymus (JART). A total of 1286 patients with thymomectomy: resection of thymoma with partial thymectomy (n = 289) or thymothymomectomy: resection of thymoma with total thymectomy (n = 997) for stage I thymoma were included. Surgical and oncologic outcomes were compared between the 2 groups.


RESULTS
Patients who underwent thymomectomy were older (61.1 versus 57.0 years; p = 0.000) and had smaller tumors (4.77 versus 5.99 cm; p = 0.000) than those who underwent thymothymomectomy. There was a significant difference in the distribution of histologic subtype (p = 0.007). After propensity-score matching, the matched cohort consisted of 276 patients in each group. Postoperative complications were seen more frequently in the thymothymomectomy group than in the thymomectomy group (8.3% versus 4.3%; p = 0.0397). The 5-year overall survival rate was 97.3% in the thymomectomy group and 96.9% in the thymothymomectomy group (p = 0.487). Patients who underwent thymomectomy tended to have local recurrence more frequently than did those who underwent thymothymomectomy (2.2% versus 0.4%; p = 0.0613).


CONCLUSIONS
Thymomectomy alone is acceptable for stage I thymoma in regard to postoperative complications and prognosis. Further studies are needed to evaluate long-term outcomes.
Department of Thoracic Surgery, National Cancer Center Hospital, Tokyo, Japan. Electronic address: kznakaga@ncc.go.jp.
Kazuo
K
Nakagawa
Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Kohei
K
Yokoi
Department of Thoracic Surgery, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
Jun
J
Nakajima
Second Department of Surgery, University of Occupational and Environmental Health, Kitakyushu, Japan.
Fumihiro
F
Tanaka
Division of Thoracic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
Yoshimasa
Y
Maniwa
Department of Thoracic Surgery, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan.
Makoto
M
Suzuki
Department of Surgical Oncology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Takeshi
T
Nagayasu
Department of Thoracic Surgery, National Cancer Center Hospital, Tokyo, Japan.
Hisao
H
Asamura
D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D057216:Propensity Score; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D013934:Thymectomy / Q000379:methods*; D013945:Thymoma / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D016896:Treatment Outcome