International Journal of Radiation Oncology*Biology*Physics
Clinical InvestigationStereotactic Body Radiotherapy (SBRT) for Operable Stage I Non–Small-Cell Lung Cancer: Can SBRT Be Comparable to Surgery?
Introduction
With the popularization of computed tomography (CT) screening, lung cancers are increasingly detected at an early stage. For patients with Stage I (T1 or 2, N0, M0) non–small-cell lung cancer (NSCLC), resection of the set of full lobar and systemic lymph nodes represents standard treatment. Five-year overall survival rates for clinical Stage IA and IB treated surgically are approximately 60–75% and 40–60%, respectively 1, 2, 3. However, a proportion of patients who meet the criteria for surgery refuse such intervention for various reasons. Radiotherapy offers a therapeutic alternative in such cases, but the effects of conventional radiotherapy in patients with Stage I NSCLC are unsatisfactory, with local control rates of approximately 50% during a short 5-year survival period in 15–30% of patients 4, 5, 6, 7. Survival rates for conventional radiotherapy for a statistically sufficient number of cases of operable Stage I NSCLC have not been reported, because most patients receiving radiotherapy are inoperable. The poor local control rates with conventional radiotherapy have been attributed to doses of conventional radiotherapy that are too low to control the tumor. Mehta et al. (8) provided a detailed theoretical analysis of NSCLC responses to radiotherapy and a rationale for dose escalation. They concluded that higher biologically effective doses (BED) irradiated during a short period must be administered to achieve successful local control of lung cancer. To provide a higher dose to the tumor without increasing adverse effects, three-dimensional conformal radiotherapy techniques have been used, and better local control and survival have recently been reported 9, 10, 11. Over the last decade, hypofractionated high-dose stereotactic body radiotherapy (SBRT) has been actively performed for early-stage lung cancer, particularly in Japan 12, 13, 14, 15, 16, 17. We have previously reported preliminary results for a Japanese multi-institutional review of 257 patients with Stage I NSCLC treated with SBRT (18). The results showed that local control and survival rates were better with BED ≥100 Gy than with <100 Gy, and survival rates were much better for medically operable patients than for medically inoperable patients. These results were encouraging, but the duration of follow-up for the study was somewhat short (median, 38 months), and we have not presented a detailed analysis of medically operable patients as a distinct subgroup. Although the standard therapy for operable Stage I NSCLC remains surgery, the effect of SBRT on medically operable patients is an issue of great concern. We provide herein detailed and matured results of SBRT (BED ≥100 Gy) for medically operable patients with Stage I NSCLC, using a retrospectively collected Japanese multi-institutional database.
Section snippets
Eligibility criteria
All patients who satisfied the following eligibility criteria were retrospectively collected from 14 major Japanese institutions in which SBRT for lung cancer was actively performed: (1) identification of T1N0M0 or T2N0M0 primary lung cancer on chest and abdominal CT, bronchoscopy, bone scintigraphy, or brain magnetic resonance imaging; (2) histopathologic confirmation of NSCLC; (3) medically operable cancer but selection of SBRT after refusal to undergo surgery. Medical operability was
Results
All patients completed treatment without obvious complaints. Median durations of observation for all patients and survivors as of final follow-up were 55 and 63 months, respectively.
Discussion
Exposing a tumor to a higher dose of radiation without increasing adverse effects can be achieved using stereotactic techniques. Stereotactic irradiation is an approach using multiple noncoplanar convergent beams, precise localization with a stereotactic coordinate system, rigid immobilization, and single high-dose treatment, maximizing delivery to the tumor and minimizing the exposure of normal tissue. This approach can also substantially reduce overall treatment time from several weeks of
Acknowledgments
The authors thank the patients and staff who assisted in this study.
References (33)
- et al.
Prognosis and survival after resection for bronchogenic carcinoma based on the 1997 TNM-staging classification: The Japanese experience
Ann Thorac Surg
(2001) - et al.
Radiotherapy alone for medically inoperable stage I non-small-cell lung cancer: The Duke experience
Int J Radiat Oncol Biol Phys
(1998) - et al.
Local irradiation alone for peripheral stage I lung cancer: Could we omit the elective regional nodal irradiation?
Int J Radiat Oncol Biol Phys
(1996) - et al.
Limited field irradiation for medically inoperable patients with peripheral stage I non-small cell lung cancer
Lung Cancer
(1999) - et al.
A new approach to dose escalation in non-small cell lung cancer
Int J Radiat Oncol Biol Phys
(2001) - et al.
High-dose radiation improved local tumor control and overall survival in patients with inoperable/unresectable non-small cell lung cancer: Long-term results of a radiation dose escalation study
Int J Radiat Oncol Biol Phys
(2005) - et al.
Results following treatment to dose of 92.4 or 102.9 Gy on a phase I dose escalation study for non-small cell lung cancer
Lung Cancer
(2004) - et al.
Comparison of outcomes for patients with medically inoperable Stage I non-small-cell lung cancer treated with two-dimensional vs. three-dimensional radiotherapy
Int J Radiat Oncol Biol Phys
(2006) - et al.
Computed tomography-guided frameless stereotactic radiography for stage I non-small-cell lung cancer: 5-year experience
Int J Radiat Oncol Biol Phys
(2001) - et al.
Clinical outcomes of a phase I/II study of 48Gy of stereotactic body radiotherapy in 4 fractions for primary lung cancer using a stereotactic body frame
Int J Radiat Oncol Biol Phys
(2005)
Steep dose-response relationship for stage I non-small-cell lung cancer using hypofractionated high-dose irradiation by real-time tumor-tracking radiotherapy
Int J Radiat Oncol Biol Phys
Clinical outcomes of stereotactic radiotherapy for stage I non-small cell lung cancer using a novel irradiation technique: Patient self-controlled breath-hold and beam switching using a combination of linear accelerator and CT scanner
Lung Cancer
Stereotactic body radiotherapy for primary lung cancer at a dose of 50Gy total in five fractions to the periphery of the planning target volume calculated using a superposition algorithm
Int J Radiat Oncol Biol Phys
A phase II study on stereotactic body radiotherapy for stage I non-small cell lung cancer
Radiother Oncol
Hypofractionated stereotactic radiotherapy (HypoFXSRT) for stage I non-small cell lung cancer: Updated results of 257 patients in a Japanese multi-institutional study
J Thorac Oncol
On using the linear-quadratic model in daily clinical practice
Int J Radiat Oncol Biol Phys
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Supported in part by a Grant-in-Aid from the Ministry of Health, Welfare and Labor of Japan.
Conflict of interest: none.