Yasushi Hamamoto

Local Control of Metastatic Lung Tumors Treated with SBRT of 48 Gy in Four Fractions: In Comparison with Primary Lung Cancer

OBJECTIVE The optimal dose of stereotactic body radiotherapy (SBRT) for metastatic lung tumors has not been clarified. Local control rates of metastatic lung tumors treated with SBRT of 48 Gy in four fractions, which is one of the common dose schedules for Stage I primary lung cancer in Japan, were examined. METHODS Between 2006 and 2008, 12 metastatic lung tumors (colorectal cancer, 7; others, 5) in 10 patients and 56 lesions of Stage I primary lung cancer (T1, 43; T2, 13) in 52 patients were treated with SBRT of 48 Gy in four fractions at the isocenter. RESULTS Two-year overall survival rates were 86% for patients with metastatic lung tumors and 96% for patients with Stage I primary lung cancer (P = 0.4773). One- and 2-year local control rates were 48% and 25% for metastatic lung tumors, and 91% and 88% for Stage I primary lung cancer, respectively (P < 0.0001). CONCLUSIONS The local control rates after SBRT of 48 Gy in four fractions were significantly worse in metastatic lung tumors compared with Stage I primary lung cancer. In SBRT, metastatic lung tumors should be clearly differentiated from primary lung cancer and should be given higher doses.

Relationship between Pretreatment FDG Uptake and Local Control after Stereotactic Body Radiotherapy in Stage I Non-small-cell Lung Cancer: The Preliminary Results

OBJECTIVE Relationship between pretreatment uptake of (18)F-fluoro-2-deoxy-d-glucose and local control after stereotactic body radiotherapy in stage I non-small-cell lung cancer was examined. METHODS Between June 2006 and June 2009, 90 clinically diagnosed stage I primary lung cancer in 86 patients were treated with stereotactic body radiotherapy in Shikoku Cancer Center. Among these, 51 tumors in 51 patients were evaluated by positron emission tomography using (18)F-fluoro-2-deoxy-d-glucose before treatment. Twenty-six tumors of histopathologically confirmed non-small-cell lung cancer were reviewed in this study. Tumors were divided into two groups by the threshold maximum standardized uptake value of 5.0 (high-uptake tumors, 9; low-uptake tumors, 17). One tumor with low uptake was pure ground-glass opacity. Typically, 48 Gy in four fractions was given at the isocenter. RESULTS Follow-up time was 4-44 months (median, 21 months). Local failure-free rates at 15 months of the high-uptake group and the low-uptake group were 40% and 93% for all tumors (P= 0.0001), 0% and 91% for tumors 3 cm or less (P= 0.0004), 50% and 100% for tumors larger than 3 cm, and 40% and 89% for the mainly solid tumors (P= 0.0010). There were no statistically significant differences of local failure-free rates according to age, sex and tumor size (P= 0.4804, P= 0.4170 and P= 0.3638, respectively). CONCLUSIONS High uptake of (18)F-fluoro-2-deoxy-d-glucose in a primary tumor was the significant unfavorable factor for local control after stereotactic body radiotherapy in stage I non-small-cell lung cancer.

Vertebral Metastases with High Risk of Symptomatic Malignant Spinal Cord Compression

OBJECTIVE To find vertebral metastases with high risk of symptomatic malignant spinal cord compression (MSCC), features of vertebral metastases caused motor deficits of the lower extremities were examined. METHODS From 2004 through 2006, 78 patients with metastases of the thoracic and/or the cervical spine were treated with radiation therapy (RT). Of these, 86 irradiated lesions in 73 patients were evaluable by magnetic resonance imaging and/or computed tomography at the initiation of RT and were reviewed retrospectively in this study. Twenty-eight patients (38%) had motor deficits at the initiation of RT. Assessed factors were age, sex, primary disease (lung, breast, digestive system and other cancer), lamina involvement, main level of tumor location and vertebral-body involvement. RESULTS Incidence of motor deficits at the initiation of RT was 55% for lesions with lamina involvement and 5% for lesions without lamina involvement (P < 0.0001). Incidence of motor deficits was 15% for lesions located mainly in the cervical spine and/or the upper thoracic spine (Th1-4), 54% for lesions located mainly in the middle thoracic spine (MTS) (Th5-8) and 30% for lesions located mainly in the lower thoracic spine (Th9-12) (P = 0.0095). Age, sex, primary disease and vertebral-body involvement were not statistically significant factors for incidence of motor deficits due to MSCC (P > 0.9999, P = 0.7798, P = 0.1702 and P = 0.366, respectively). CONCLUSIONS Vertebral metastases with lamina involvement tended to cause symptomatic MSCC. Latent development of MSCC occurred more frequently in the MTS compared with other levels of the thoracic and the cervical spine.

Development of a real-time monitoring system for intra-fractional motion in intracranial treatment using pressure sensors.

This study developed a dedicated real-time monitoring system to detect intra-fractional head motion in intracranial radiotherapy using pressure sensors. The dedicated real-time monitoring system consists of pressure sensors with a thickness of 0.6 mm and a radius of 9.1 mm, a thermoplastic mask, a vacuum pillow, and a baseplate. The four sensors were positioned at superior-inferior and right-left sides under the occipital area. The sampling rate of pressure sensors was set to 5 Hz. First, we confirmed that the relationship between the force and the displacement of the vacuum pillow follows Hooks law. Next, the spring constant for the vacuum pillow was determined from the relationship between the force given to the vacuum pillow and the displacement of the head, detected by Cyberknife target locating system (TLS) acquisitions in clinical application. Finally, the accuracy of our system was evaluated by using the 2  ×  2 confusion matrix. The regression lines between the force, y, and the displacement, x, of the vacuum pillow were given by y = 3.8x, y = 4.4x, and y = 5.0x when the degree of inner pressure was  -12 kPa,-20 kPa, and  -27 kPa, respectively. The spring constant of the vacuum pillow was 1.6 N mm(-1) from the 6D positioning data of a total of 2999 TLS acquisitions in 19 patients. Head motions of 1 mm, 1.5 mm, and 2 mm were detected in real-time with the accuracies of 67%, 84%, and 89%, respectively. Our system can detect displacement of the head continuously during every interval of TLS with a resolution of 1-2 mm without any radiation exposure.

Supraclavicular failure after breast-conserving therapy in patients with four or more positive axillary lymph nodes when prophylactic supraclavicular irradiation is omitted

PurposeThe incidence of supraclavicular metastasis as the initial failure and the failure patterns in patients with four or more positive axillary lymph nodes (PALNs) after breast-conserving therapy (BCT) without prophylactic supraclavicular irradiation were investigated.Materials and methodsBetween 1991 and 2002, a total of 48 women with four or more PALNs underwent BCT without prophylactic supraclavicular irradiation (33 patients with 4–9 PALNs; 15 patients with ≥10 PALNs).ResultsThe median follow-up time was 50 months. Among the patients with 4–9 PALNs, 3% had isolated supraclavicular metastasis as the initial failure, and 30% had distant metastasis as the initial failure. Among patients with ≥10 PALNs, 7% had isolated supraclavicular metastasis as the initial failure, and 40% had distant metastasis as the initial failure. The 4-year isolated supraclavicular failure rates were 5% for all patients, 3% for patients with 4–9 PALNs, and 8% for patients with ≥10 PALNs.ConclusionIn patients who had undergone BCT and had had four or more PALNs, the major failure pattern was distant failure with or without locoregional failure; isolated supraclavicular failure as the initial failure comprised a less common failure pattern. Omission of prophylactic supraclavicular irradiation may be acceptable for this subset of patients.

Incidence and patterns of isolated brain failure in stage III non-small-cell lung cancer treated with concurrent chemoradiation therapy.

PurposeThe incidence and patterns of isolated brain failure was examined in patients with stage III non-small-cell lung cancer (NSCLC) treated with concurrent chemoradiation (CCRT).Materials and methodsBetween 1996 and 2003, a total of 68 patients with stage III NSCLC were treated with radical CCRT. Among them, 63 patients were evaluable. Radiation therapy with a mean total dose of 61.4 Gy and chemotherapy (typically platinum-based) were administered concurrently.ResultsOther than locoregional failure, isolated brain failure was the most common failure pattern as the initial failure, occurring 2–37 months (median 6.5 months) after radical CCRT. The isolated brain failure rates as the initial failure at 1, 3, and 4 years were 9%, 13%, and 25%, respectively. Isolated brain failure as the initial failure occurred more frequently in T4 cases (39% at 4 years) compared to T1–3 cases (14% at 4 years) in our series (P = 0.0099).ConclusionExcept for locoregional failure, isolated brain failure was the most common initial failure pattern of stage III NSCLCs treated with radical CCRT. Isolated brain failure as the initial failure occurred even after 3 years. Isolated brain failure as the initial failure occurred more frequently in T4 cases than in T1-3 cases.

Risk factors for pericardial effusion after chemoradiotherapy for thoracic esophageal cancer—comparison of four-field technique and traditional two opposed fields technique

Abstract Pericardial effusion is an important late toxicity after concurrent chemoradiotherapy (CCRT) for locally advanced esophageal cancer. We investigated the clinical and dosimetric factors that were related to pericardial effusion among patients with thoracic esophageal cancer who were treated with definitive CCRT using the two opposed fields technique (TFT) or the four-field technique (FFT), as well as the effectiveness of FFT. During 2007–2015, 169 patients with middle and/or lower thoracic esophageal cancer received definitive CCRT, and 94 patients were evaluable (51 FFT cases and 43 TFT cases). Pericardial effusion was observed in 74 patients (79%) and appeared at 1–18.5 months (median: 5.25 months) after CCRT. The 1-year incidences of pericardial effusions were 73.2% and 76.7% in the FFT and TFT groups, respectively (P = 0.6395). The mean doses to the pericardium were 28.6 Gy and 31.8 Gy in the FFT and TFT groups, respectively (P = 0.0259), and the V40 Gy proportions were 33.5% and 48.2% in the FFT and TFT groups, respectively (P < 0.0001). Grade 3 pericardial effusion was not observed in patients with a pericardial V40 Gy of <40%, or in patients who were treated using the FFT. Although the mean pericardial dose and V40 Gy in the FFT group were smaller than those in the TFT group, the incidences of pericardial effusion after CCRT were similar in both groups. As symptomatic pericardial effusion was not observed in patients with a pericardial V40 Gy of <40% or in the FFT group, it appears that FFT with a V40 Gy of <40% could help minimize symptomatic pericardial effusion.