Toru Akiyama1, Koichi Ogura2,3, Tabu Gokita4, Satoshi Tsukushi5, Shintaro Iwata6, Tomoki Nakamura7, Akihiko Matsumine7, Tsukasa Yonemoto6, Yoshihiro Nishida8, Kazuo Saita9, Akira Kawai2, Seiichi Matsumoto4, Takehiko Yamaguchi10. 1. Department of Orthopaedic Surgery, Saitama Medical Center, Jichi Medical University, Saitama, Japan. toruakiyama827@jichi.ac.jp. 2. Department of Musculoskeletal Oncology, National Cancer Center Hospital, Tokyo, Japan. 3. Department of Orthopaedic Surgery, The University of Tokyo Hospital, Tokyo, Japan. 4. Department of Orthopedic Surgery, Cancer Institute Hospital, Tokyo, Japan. 5. Department of Orthopedic Surgery, Aichi Cancer Center Hospital, Aichi, Japan. 6. Division of Orthopaedic Surgery, Chiba Cancer Center, Chiba, Japan. 7. Department of Orthopaedic Surgery, Mie University Hospital, Mie, Japan. 8. Department of Orthopaedic Surgery, Nagoya University Graduate School and School of Medicine, Aichi, Japan. 9. Department of Orthopaedic Surgery, Saitama Medical Center, Jichi Medical University, Saitama, Japan. 10. Department of Pathology, Saitama Medical Center, Dokkyo Medical University, Koshigaya, Japan.
Abstract
BACKGROUND: Chordomas are very rare primary malignant bone tumors that arise commonly from the sacrum (50-60%) and clivus (25-35%). Chordomas have a high rate of recurrence. The authors confirmed a unique histologic infiltration pattern of chordomas that resembles a skip-metastatic lesion in normal tissue around tumor, which they named "micro-skip metastasis." This study aimed to examine the correlations between the clinicopathologic features of chordomas, including micro-skip metastasis, and the clinical outcomes, including overall survival, local recurrence-free survival, and distant metastasis-free survival. METHODS: The study analyzed histopathologic and clinical data from patients with sacral chordomas who underwent en bloc resection from July 1991 through July 2014. Cases with a minimum follow-up period shorter than 20 months after resection were excluded. Kaplan-Meier survival analyses with log-rank tests were performed for overall survival, metastasis-free survival, and recurrence-free survival. RESULTS: The study retrospectively reviewed 40 patients. The mean follow-up period was 98.2 months (range 22-297 months). The local recurrence rate was 41.3%. Micro-skip metastases, observed in 17 patients (42.5%), were associated with a significantly increased risk of local recurrence (p = 0.023) but not with overall survival or distant metastasis-free survival. Poorer overall survival was associated with histologic vascular invasion (p = 0.030) and a greater maximum tumor diameter (p = 0.050). CONCLUSIONS: The presence of micro-skip metastasis was associated with a higher rate of local recurrence. The maximum tumor diameter and the presence of histologic vascular invasion were associated with poorer overall survival.
BACKGROUND:Chordomas are very rare primary malignant bone tumors that arise commonly from the sacrum (50-60%) and clivus (25-35%). Chordomas have a high rate of recurrence. The authors confirmed a unique histologic infiltration pattern of chordomas that resembles a skip-metastatic lesion in normal tissue around tumor, which they named "micro-skip metastasis." This study aimed to examine the correlations between the clinicopathologic features of chordomas, including micro-skip metastasis, and the clinical outcomes, including overall survival, local recurrence-free survival, and distant metastasis-free survival. METHODS: The study analyzed histopathologic and clinical data from patients with sacral chordomas who underwent en bloc resection from July 1991 through July 2014. Cases with a minimum follow-up period shorter than 20 months after resection were excluded. Kaplan-Meier survival analyses with log-rank tests were performed for overall survival, metastasis-free survival, and recurrence-free survival. RESULTS: The study retrospectively reviewed 40 patients. The mean follow-up period was 98.2 months (range 22-297 months). The local recurrence rate was 41.3%. Micro-skip metastases, observed in 17 patients (42.5%), were associated with a significantly increased risk of local recurrence (p = 0.023) but not with overall survival or distant metastasis-free survival. Poorer overall survival was associated with histologic vascular invasion (p = 0.030) and a greater maximum tumor diameter (p = 0.050). CONCLUSIONS: The presence of micro-skip metastasis was associated with a higher rate of local recurrence. The maximum tumor diameter and the presence of histologic vascular invasion were associated with poorer overall survival.