We retrospectively evaluated the clinical outcomes of patients with oligometastatic lung tumors who underwent stereotactic body radiotherapy (SBRT). Twenty-two patients with one or two oligometastatic lung tumors were treated with SBRT at our institution between 1999 and 2009. With a median follow-up period of 25 months from the date of SBRT to the detection of oligometastatic lung tumors, the patients' 3- and 5-year overall survival (OS) and progression-free survival (PFS) rates were 72% and 54%, respectively. The median disease-free interval (DFI) between the treatment of the primary site and SBRT to oligometastatic lung tumors was 41 months. The OS of patients with a DFI ≥？36 months was significantly longer than that of the patients with a DFI < 36 months by the log-rank test ( ). For patients with a DFI ≥？36 months, the 3- and 5-year OS rates were both 88%, compared to 50% for the patients with a DFI <？36 months. The primary tumor of all patients was locally controlled when SBRT to oligometastatic lung tumors was performed, and thus they were in the state of “oligo-recurrence.” Patients with oligometastatic lung lesions treated by SBRT had good prognoses. This was especially true of the patients with a long DFI and in the state of “oligo-recurrence.” 1. Introduction Most patients who have had any recurrent or metastatic sites of cancer are considered to be in their last stage of life. However, new notions of oligometastases and oligo-recurrence have been proposed [1–9]. Oligometastases is the state in which the patient shows distant recurrence in only a limited number of regions. The clinical state of oligometastatic disease was proposed in 1995 by Hellman and Weichselbaum [1], who hypothesized that local control of oligometastases may yield improved systemic control and prolonged survival. Niibe et al. also discussed the state of oligo-recurrence [2–4]; they defined it as oligometastases with a controlled primary cancer site. Stereotactic body radiotherapy (SBRT) with a high local dose has been applied to extracranial diseases such as peripheral stage I nonsmall cell lung cancer (NSCLC), and it has been reported to provide excellent local control and survival compatible with surgery [10, 11]. SBRT has also been used in Japan for patients with fewer than three lung metastases ≤5？cm in diameter. In the present study, we retrospectively analyzed our experience with SBRT for patients with oligometastatic lung tumors. 2. Methods and Materials 2.1. Patient Characteristics A database of patients who received SBRT for metastatic lung tumors at our
References
[1]
S. Hellman and R. R. Weichselbaum, “Oligometastases,” Journal of Clinical Oncology, vol. 13, no. 1, pp. 8–10, 1995.
[2]
Y. Niibe, T. Kazumoto, T. Toita et al., “Frequency and characteristics of isolated para-aortic lymph node recurrence in patients with uterine cervical carcinoma in Japan: a multi-institutional study,” Gynecologic Oncology, vol. 103, no. 2, pp. 435–438, 2006.
[3]
Y. Niibe, M. Kenjo, T. Kazumoto et al., “Multi-institutional study of radiation therapy for isolated para-aortic lymph node recurrence in uterine cervical carcinoma: 84 subjects of a population of more than 5,000,” International Journal of Radiation Oncology Biology Physics, vol. 66, no. 5, pp. 1366–1369, 2006.
[4]
Y. Niibe, M. Kuranami, K. Matsunaga et al., “Value of high-dose radiation therapy for isolated osseous metastasis in breast cancer in terms of oligo-recurrence,” Anticancer Research, vol. 28, no. 6 B, pp. 3929–3931, 2008.
[5]
J. K. Salama, S. J. Chmura, N. Mehta et al., “An initial report of a radiation dose-escalation trial in patients with one to five sites of metastatic disease,” Clinical Cancer Research, vol. 14, no. 16, pp. 5255–5259, 2008.
[6]
M. T. Milano, A. W. Katz, A. G. Muhs et al., “A prospective pilot study of curative-intent stereotactic body radiation therapy in patients with 5 or fewer oligometastatic lesions,” Cancer, vol. 112, no. 3, pp. 650–658, 2008.
[7]
T. W. Flannery, M. Suntharalingam, W. F. Regine et al., “Long-term survival in patients with synchronous, solitary brain metastasis from non-small-cell lung cancer treated with radiosurgery,” International Journal of Radiation Oncology Biology Physics, vol. 72, no. 1, pp. 19–23, 2008.
[8]
M. T. Milano, H. Zhang, S. K. Metcalfe, A. G. Muhs, and P. Okunieff, “Oligometastatic breast cancer treated with curative-intent stereotactic body radiation therapy,” Breast Cancer Research and Treatment, vol. 115, no. 3, pp. 601–608, 2009.
[9]
A. J. Khan, P. S. Mehta, T. W. Zusag et al., “Long term disease-free survival resulting from combined modality management of patients presenting with oligometastatic, non-small cell lung carcinoma (NSCLC),” Radiotherapy and Oncology, vol. 81, no. 2, pp. 163–167, 2006.
[10]
H. Onishi, H. Shirato, Y. Nagata et al., “Hypofractionated stereotactic radiotherapy (HypoFXSRT) for stage I non-small cell lung cancer: updated results of 257 patients in a Japanese multi-institutional study,” Journal of Thoracic Oncology, vol. 2, supplement 7, pp. S94–S100, 2007.
[11]
P. Baumann, J. Nyman, M. Hoyer et al., “Outcome in a prospective phase II trial of medically inoperable stage I non-small-cell lung cancer patients treated with stereotactic body radiotherapy,” Journal of Clinical Oncology, vol. 27, no. 20, pp. 3290–3296, 2009.
[12]
H. Shirato, S. Shimizu, T. Kunieda et al., “Physical aspects of a real-time tumor-tracking system for gated radiotherapy,” International Journal of Radiation Oncology Biology Physics, vol. 48, no. 4, pp. 1187–1195, 2000.
[13]
H. Shirato, S. Shimizu, K. Kitamura et al., “Four-dimensional treatment planning and fluoroscopic real-time tumor tracking radiotherapy for moving tumor,” International Journal of Radiation Oncology Biology Physics, vol. 48, no. 2, pp. 435–442, 2000.
[14]
Y. Norihisa, Y. Nagata, K. Takayama et al., “Stereotactic body radiotherapy for oligometastatic lung tumors,” International Journal of Radiation Oncology Biology Physics, vol. 72, no. 2, pp. 398–403, 2008.
[15]
K. E. Rusthoven, B. D. Kavanagh, S. H. Burri, et al., “Multi-institutional phase I/II trial of stereotactic body radiation therapy for lung metastases,” Journal of Clinical Oncology, vol. 27, no. 10, pp. 1579–1584, 2009.
[16]
The International Registry of Lung Metastases, “Long-term results of lung metastasectomy: prognostic analyses based on 5206 cases,” Journal of Thoracic and Cardiovascular Surgery, vol. 113, no. 1, pp. 37–49, 1997.
[17]
T. Inoue, N. Katoh, H. Aoyama et al., “Clinical outcomes of stereotactic brain and/or body radiotherapy for patients with oligometastatic lesions,” Japanese Journal of Clinical Oncology, vol. 40, no. 8, pp. 788–794, 2010.
