Alex Sun | Williams College (original) (raw)
Papers by Alex Sun
Radiotherapy and Oncology, 1998
Background and purpose: Hypoxia appears to be an important factor in predicting tumor relapse fol... more Background and purpose: Hypoxia appears to be an important factor in predicting tumor relapse following radiation therapy. This study measured oxygenation prior to treatment in patients with cervix cancer using a polarographic oxygen electrode to determine if oxygenation was an important prognostic factor with regard to tumor control and survival.
International Journal of Radiation Oncology Biology Physics, 2003
To examine the impact of extranodal chest wall and lung invasion on the prognosis of patients wit... more To examine the impact of extranodal chest wall and lung invasion on the prognosis of patients with clinical Stage I-II Hodgkin's lymphoma treated with combined modality therapy. The outcome of 324 patients with clinical Stage I-II Hodgkin's lymphoma treated with combined modality therapy between 1981 and 1996 was analyzed. Twenty-two patients had chest wall invasion and 40 had invasion of lung parenchyma. The chemotherapy regimens used were ABVD in 182 patients (56%), MOPP/ABV(D) in 45 (14%), MOPP in 86 (27%), and other chemotherapy regimens in 11 patients (3%). This was followed by mantle/mediastinal radiotherapy (RT) in 163 patients (50%), extended-field RT in 135 patients (42%), and infradiaphragmatic RT in 26 patients (8%). The impact of chest wall and lung invasion on local relapse, disease-free survival, cause-specific survival, and overall survival was examined. After a median follow-up of 8.3 years, the 5-year cause-specific and overall survival rate of the entire cohort was 93% and 90%, respectively. Compared with patients with no extranodal involvement, patients with chest wall invasion had significantly worse local control (89% vs. 68%, p = 0.005), disease-free survival (84% vs. 59%, p = 0.016), and cause-specific survival (94% vs. 86%, p = 0.009). Overall survival was also worse among patients with chest wall invasion, but not significantly so (90% vs. 82%, p = 0.10). Among the 16 patients with chest wall invasion but without lung invasion, 7 progressed during treatment or relapsed, 6 with local failure (crude relapse rate 44%, 95% confidence interval [CI] 19-68%), and 5 died (crude death rate 31%, 95% CI 9-54%). After adjusting for other significant prognostic factors, patients with chest wall invasion had significantly worse local control (hazard ratio 2.8, 95% CI 1.2-6.3), disease-free survival (hazard ratio 2.3, 95% CI 1.1-4.8), and cause-specific survival (hazard ratio 2.8, 95% CI 1.1-6.8). Lung invasion was not significantly associated with any of the outcomes assessed. Chest wall invasion is an adverse prognostic factor among clinical Stage I-II Hodgkin's lymphoma patients treated with combined modality therapy, although we did not find a worse outcome for patients with lung invasion. Efforts to reduce treatment intensity in these patients should be undertaken with caution, recognizing their increased risk of local relapse.
Journal of Thoracic Oncology, 2007
Lung Cancer, 2003
Background: Aggressive multimodality treatment may offer disease control in selected patients wit... more Background: Aggressive multimodality treatment may offer disease control in selected patients with malignant mesothelioma. However, delivery of radiother-aW (FIT) to the hemithorax is challenging. We describe the "learning curve" in our institution, a major tertiary cancer center, with availability of modern RT planning and delivery equipment and an experienced multidisciplinary approach to management of thoracic tumors.
International Journal of Radiation Oncology Biology Physics, 2006
Patients with chemotherapy-resistant lymphoma have rapidly progressive disease and a poor prognos... more Patients with chemotherapy-resistant lymphoma have rapidly progressive disease and a poor prognosis. Local symptoms are treated with radiotherapy (RT) for local control. We have reviewed local control and toxicity in patients treated with hyperfractionated accelerated RT. A total of 34 patients received hyperfractionated RT between 1997 and 2003. The radiation dose was 39.9-40.5 Gy in 30 fractions. The median treatment time was 22 days with twice-daily involved-field RT. The median follow-up was 4.4 years. Response was assessed <3 months after RT and was classified as a complete response, a complete response-unconfirmed, a partial response, or no response. Local control was defined as maintenance of local complete response, complete response-unconfirmed, or lack of local progression with a partial response. Recurrence or progression outside the RT volume was regarded as distant disease. The median age was 53 years; 20 patients were men and 14 were women. The initial diagnosis was Stage I-II in 56% and Stage III-IV in 44%. The disease bulk was > or =10 cm in 35% (n = 12). The histologic features at diagnosis were follicular in 11 (Grade 1 in 4, Grade 2 in 3, and Grade 3 in 4), diffuse large B-cell in 14, peripheral T-cell lymphoma in 2, Burkitt-like in 1, mantle cell in 2, natural killer cell in 2, plasmacytoma/lymphoma in 1, and T-cell lymphoblastic in 1. The initial treatment was chemotherapy in 32 patients (94%); 71% were refractory to initial chemotherapy and 29% developed a relapse after an initial response. The RT response was complete in 24% (n = 8), complete, unconfirmed in 26% (n = 9), partial in 47% (n = 16), and none in 3% (n = 1). The local control rate was 73% at 1, 2, and 3 years. Grade 1 dermatitis was the most common side effect. Hyperfractionated RT provided good local control and was well tolerated. This encouraging result requires additional study with comparison to conventional fractionation regimens.
International Journal of Radiation Oncology Biology Physics, 2006
Patients with chemotherapy-resistant lymphoma have rapidly progressive disease and a poor prognos... more Patients with chemotherapy-resistant lymphoma have rapidly progressive disease and a poor prognosis. Local symptoms are treated with radiotherapy (RT) for local control. We have reviewed local control and toxicity in patients treated with hyperfractionated accelerated RT. A total of 34 patients received hyperfractionated RT between 1997 and 2003. The radiation dose was 39.9-40.5 Gy in 30 fractions. The median treatment time was 22 days with twice-daily involved-field RT. The median follow-up was 4.4 years. Response was assessed <3 months after RT and was classified as a complete response, a complete response-unconfirmed, a partial response, or no response. Local control was defined as maintenance of local complete response, complete response-unconfirmed, or lack of local progression with a partial response. Recurrence or progression outside the RT volume was regarded as distant disease. The median age was 53 years; 20 patients were men and 14 were women. The initial diagnosis was Stage I-II in 56% and Stage III-IV in 44%. The disease bulk was > or =10 cm in 35% (n = 12). The histologic features at diagnosis were follicular in 11 (Grade 1 in 4, Grade 2 in 3, and Grade 3 in 4), diffuse large B-cell in 14, peripheral T-cell lymphoma in 2, Burkitt-like in 1, mantle cell in 2, natural killer cell in 2, plasmacytoma/lymphoma in 1, and T-cell lymphoblastic in 1. The initial treatment was chemotherapy in 32 patients (94%); 71% were refractory to initial chemotherapy and 29% developed a relapse after an initial response. The RT response was complete in 24% (n = 8), complete, unconfirmed in 26% (n = 9), partial in 47% (n = 16), and none in 3% (n = 1). The local control rate was 73% at 1, 2, and 3 years. Grade 1 dermatitis was the most common side effect. Hyperfractionated RT provided good local control and was well tolerated. This encouraging result requires additional study with comparison to conventional fractionation regimens.
Journal of Thoracic Oncology, 2008
With the anticipation of improved outcomes, especially for patients with early-stage non-small ce... more With the anticipation of improved outcomes, especially for patients with early-stage non-small cell lung cancer, stereotactic body radiation therapy (SBRT) has been rapidly introduced into the thoracic radiation oncology community. Although at first glance lung SBRT might seem methodologically similar to conventional radiotherapy, there are important differences in its execution that require particular consideration. The objective of this paper is to highlight these and other issues to contribute to the safe and effective diffusion of lung SBRT. We discuss practical challenges that have been encountered in the implementation of lung SBRT at a single, large institution and emphasize the importance of a systematic approach to the design of lung SBRT services. Methods: Specific technical and clinical components that were identified as being important during the development of lung SBRT at Princess Margaret Hospital are described. The clinical system that evolved from these is outlined. Results: Using this clinical framework the practical topics addressed include: patient assessment, simulation and treatment planning, tumor and organ at risk delineation, trial set up before treatment, on-line image-guidance, and patient follow-up. Conclusions: The potential gain in therapeutic ratio that is theoretically possible with lung SBRT can only be realized if the tumor is adequately irradiated and normal tissue spared. A discussion of the component parts of lung SBRT is presented. It is a complex process and specific challenges need to be overcome to effect the satisfactory transition of lung SBRT into routine practice.
International Journal of Radiation Oncology Biology Physics, 2011
To evaluate the feasibility and safety of concurrent pemetrexed/cisplatin/thoracic radiotherapy f... more To evaluate the feasibility and safety of concurrent pemetrexed/cisplatin/thoracic radiotherapy followed by consolidation pemetrexed/cisplatin for unresectable Stage IIIA/B non-small-cell lung cancer (NSCLC). Eligible patients with <5% weight loss and good performance status received two cycles of pemetrexed (300, 400, or 500 mg/m(2) on Days 1 and 22 for Dose Levels 1, 2, and 3/4, respectively) and cisplatin (25 mg/m(2) Days 1-3 for Dose Levels 1-3; 20 mg/m(2) Days 1-5 for Dose Level 4) concurrent with thoracic radiation (61-66 Gy in 31-35 fractions). Consolidation consisted of two cycles of pemetrexed/cisplatin (500 mg/m(2), 75 mg/m(2)) 21 days apart, after concurrent therapy. Between January 2006 and October 2007, 16 patients entered the study. Median follow-up was 17.2 months. No dose-limiting toxicities were observed. Median radiation dose was 64 Gy (range, 45-66 Gy). Rates of significant Grade 3/4 hematologic toxicity were 38% and 7%, respectively. One patient experienced Grade 3 acute esophagitis, and 2 experienced late (Grade 3) esophageal stricture, successfully managed with dilation. One patient experienced Grade 3 pneumonitis. The overall response rate was 88%. One-year overall survival was 81%. Full systemic dose pemetrexed seems to be safe with full-dose cisplatin and thoracic radiation in Stage IIIA/B NSCLC. Pemetrexed is the first third-generation cytotoxic agent tolerable at full dose in this setting. A Phase II study evaluating Dose Level 4 is ongoing.
Journal of Thoracic Oncology, 2009
Stereotactic body radiotherapy is an emerging treatment option for peripheral non-small cell lung... more Stereotactic body radiotherapy is an emerging treatment option for peripheral non-small cell lung cancer in medically inoperable patients. With high dose per fraction radiotherapy, late side effects are of possible concern. In our initial cohort of 42 patients treated with 54 to 60 Gy in three fractions, nine patients have rib fracture. The median dose to rib fracture sites was 46 to 50 Gy, depending on the method of dose calculation. We describe a typical case of poststereotactic radiotherapy rib fracture and present dosimetric analysis of patients with rib fracture.
Journal of Thoracic Oncology, 2007
Radiotherapy and Oncology, 1998
Background and purpose: Hypoxia appears to be an important factor in predicting tumor relapse fol... more Background and purpose: Hypoxia appears to be an important factor in predicting tumor relapse following radiation therapy. This study measured oxygenation prior to treatment in patients with cervix cancer using a polarographic oxygen electrode to determine if oxygenation was an important prognostic factor with regard to tumor control and survival.
International Journal of Radiation Oncology Biology Physics, 2003
To examine the impact of extranodal chest wall and lung invasion on the prognosis of patients wit... more To examine the impact of extranodal chest wall and lung invasion on the prognosis of patients with clinical Stage I-II Hodgkin's lymphoma treated with combined modality therapy. The outcome of 324 patients with clinical Stage I-II Hodgkin's lymphoma treated with combined modality therapy between 1981 and 1996 was analyzed. Twenty-two patients had chest wall invasion and 40 had invasion of lung parenchyma. The chemotherapy regimens used were ABVD in 182 patients (56%), MOPP/ABV(D) in 45 (14%), MOPP in 86 (27%), and other chemotherapy regimens in 11 patients (3%). This was followed by mantle/mediastinal radiotherapy (RT) in 163 patients (50%), extended-field RT in 135 patients (42%), and infradiaphragmatic RT in 26 patients (8%). The impact of chest wall and lung invasion on local relapse, disease-free survival, cause-specific survival, and overall survival was examined. After a median follow-up of 8.3 years, the 5-year cause-specific and overall survival rate of the entire cohort was 93% and 90%, respectively. Compared with patients with no extranodal involvement, patients with chest wall invasion had significantly worse local control (89% vs. 68%, p = 0.005), disease-free survival (84% vs. 59%, p = 0.016), and cause-specific survival (94% vs. 86%, p = 0.009). Overall survival was also worse among patients with chest wall invasion, but not significantly so (90% vs. 82%, p = 0.10). Among the 16 patients with chest wall invasion but without lung invasion, 7 progressed during treatment or relapsed, 6 with local failure (crude relapse rate 44%, 95% confidence interval [CI] 19-68%), and 5 died (crude death rate 31%, 95% CI 9-54%). After adjusting for other significant prognostic factors, patients with chest wall invasion had significantly worse local control (hazard ratio 2.8, 95% CI 1.2-6.3), disease-free survival (hazard ratio 2.3, 95% CI 1.1-4.8), and cause-specific survival (hazard ratio 2.8, 95% CI 1.1-6.8). Lung invasion was not significantly associated with any of the outcomes assessed. Chest wall invasion is an adverse prognostic factor among clinical Stage I-II Hodgkin's lymphoma patients treated with combined modality therapy, although we did not find a worse outcome for patients with lung invasion. Efforts to reduce treatment intensity in these patients should be undertaken with caution, recognizing their increased risk of local relapse.
Journal of Thoracic Oncology, 2007
Lung Cancer, 2003
Background: Aggressive multimodality treatment may offer disease control in selected patients wit... more Background: Aggressive multimodality treatment may offer disease control in selected patients with malignant mesothelioma. However, delivery of radiother-aW (FIT) to the hemithorax is challenging. We describe the "learning curve" in our institution, a major tertiary cancer center, with availability of modern RT planning and delivery equipment and an experienced multidisciplinary approach to management of thoracic tumors.
International Journal of Radiation Oncology Biology Physics, 2006
Patients with chemotherapy-resistant lymphoma have rapidly progressive disease and a poor prognos... more Patients with chemotherapy-resistant lymphoma have rapidly progressive disease and a poor prognosis. Local symptoms are treated with radiotherapy (RT) for local control. We have reviewed local control and toxicity in patients treated with hyperfractionated accelerated RT. A total of 34 patients received hyperfractionated RT between 1997 and 2003. The radiation dose was 39.9-40.5 Gy in 30 fractions. The median treatment time was 22 days with twice-daily involved-field RT. The median follow-up was 4.4 years. Response was assessed <3 months after RT and was classified as a complete response, a complete response-unconfirmed, a partial response, or no response. Local control was defined as maintenance of local complete response, complete response-unconfirmed, or lack of local progression with a partial response. Recurrence or progression outside the RT volume was regarded as distant disease. The median age was 53 years; 20 patients were men and 14 were women. The initial diagnosis was Stage I-II in 56% and Stage III-IV in 44%. The disease bulk was > or =10 cm in 35% (n = 12). The histologic features at diagnosis were follicular in 11 (Grade 1 in 4, Grade 2 in 3, and Grade 3 in 4), diffuse large B-cell in 14, peripheral T-cell lymphoma in 2, Burkitt-like in 1, mantle cell in 2, natural killer cell in 2, plasmacytoma/lymphoma in 1, and T-cell lymphoblastic in 1. The initial treatment was chemotherapy in 32 patients (94%); 71% were refractory to initial chemotherapy and 29% developed a relapse after an initial response. The RT response was complete in 24% (n = 8), complete, unconfirmed in 26% (n = 9), partial in 47% (n = 16), and none in 3% (n = 1). The local control rate was 73% at 1, 2, and 3 years. Grade 1 dermatitis was the most common side effect. Hyperfractionated RT provided good local control and was well tolerated. This encouraging result requires additional study with comparison to conventional fractionation regimens.
International Journal of Radiation Oncology Biology Physics, 2006
Patients with chemotherapy-resistant lymphoma have rapidly progressive disease and a poor prognos... more Patients with chemotherapy-resistant lymphoma have rapidly progressive disease and a poor prognosis. Local symptoms are treated with radiotherapy (RT) for local control. We have reviewed local control and toxicity in patients treated with hyperfractionated accelerated RT. A total of 34 patients received hyperfractionated RT between 1997 and 2003. The radiation dose was 39.9-40.5 Gy in 30 fractions. The median treatment time was 22 days with twice-daily involved-field RT. The median follow-up was 4.4 years. Response was assessed <3 months after RT and was classified as a complete response, a complete response-unconfirmed, a partial response, or no response. Local control was defined as maintenance of local complete response, complete response-unconfirmed, or lack of local progression with a partial response. Recurrence or progression outside the RT volume was regarded as distant disease. The median age was 53 years; 20 patients were men and 14 were women. The initial diagnosis was Stage I-II in 56% and Stage III-IV in 44%. The disease bulk was > or =10 cm in 35% (n = 12). The histologic features at diagnosis were follicular in 11 (Grade 1 in 4, Grade 2 in 3, and Grade 3 in 4), diffuse large B-cell in 14, peripheral T-cell lymphoma in 2, Burkitt-like in 1, mantle cell in 2, natural killer cell in 2, plasmacytoma/lymphoma in 1, and T-cell lymphoblastic in 1. The initial treatment was chemotherapy in 32 patients (94%); 71% were refractory to initial chemotherapy and 29% developed a relapse after an initial response. The RT response was complete in 24% (n = 8), complete, unconfirmed in 26% (n = 9), partial in 47% (n = 16), and none in 3% (n = 1). The local control rate was 73% at 1, 2, and 3 years. Grade 1 dermatitis was the most common side effect. Hyperfractionated RT provided good local control and was well tolerated. This encouraging result requires additional study with comparison to conventional fractionation regimens.
Journal of Thoracic Oncology, 2008
With the anticipation of improved outcomes, especially for patients with early-stage non-small ce... more With the anticipation of improved outcomes, especially for patients with early-stage non-small cell lung cancer, stereotactic body radiation therapy (SBRT) has been rapidly introduced into the thoracic radiation oncology community. Although at first glance lung SBRT might seem methodologically similar to conventional radiotherapy, there are important differences in its execution that require particular consideration. The objective of this paper is to highlight these and other issues to contribute to the safe and effective diffusion of lung SBRT. We discuss practical challenges that have been encountered in the implementation of lung SBRT at a single, large institution and emphasize the importance of a systematic approach to the design of lung SBRT services. Methods: Specific technical and clinical components that were identified as being important during the development of lung SBRT at Princess Margaret Hospital are described. The clinical system that evolved from these is outlined. Results: Using this clinical framework the practical topics addressed include: patient assessment, simulation and treatment planning, tumor and organ at risk delineation, trial set up before treatment, on-line image-guidance, and patient follow-up. Conclusions: The potential gain in therapeutic ratio that is theoretically possible with lung SBRT can only be realized if the tumor is adequately irradiated and normal tissue spared. A discussion of the component parts of lung SBRT is presented. It is a complex process and specific challenges need to be overcome to effect the satisfactory transition of lung SBRT into routine practice.
International Journal of Radiation Oncology Biology Physics, 2011
To evaluate the feasibility and safety of concurrent pemetrexed/cisplatin/thoracic radiotherapy f... more To evaluate the feasibility and safety of concurrent pemetrexed/cisplatin/thoracic radiotherapy followed by consolidation pemetrexed/cisplatin for unresectable Stage IIIA/B non-small-cell lung cancer (NSCLC). Eligible patients with <5% weight loss and good performance status received two cycles of pemetrexed (300, 400, or 500 mg/m(2) on Days 1 and 22 for Dose Levels 1, 2, and 3/4, respectively) and cisplatin (25 mg/m(2) Days 1-3 for Dose Levels 1-3; 20 mg/m(2) Days 1-5 for Dose Level 4) concurrent with thoracic radiation (61-66 Gy in 31-35 fractions). Consolidation consisted of two cycles of pemetrexed/cisplatin (500 mg/m(2), 75 mg/m(2)) 21 days apart, after concurrent therapy. Between January 2006 and October 2007, 16 patients entered the study. Median follow-up was 17.2 months. No dose-limiting toxicities were observed. Median radiation dose was 64 Gy (range, 45-66 Gy). Rates of significant Grade 3/4 hematologic toxicity were 38% and 7%, respectively. One patient experienced Grade 3 acute esophagitis, and 2 experienced late (Grade 3) esophageal stricture, successfully managed with dilation. One patient experienced Grade 3 pneumonitis. The overall response rate was 88%. One-year overall survival was 81%. Full systemic dose pemetrexed seems to be safe with full-dose cisplatin and thoracic radiation in Stage IIIA/B NSCLC. Pemetrexed is the first third-generation cytotoxic agent tolerable at full dose in this setting. A Phase II study evaluating Dose Level 4 is ongoing.
Journal of Thoracic Oncology, 2009
Stereotactic body radiotherapy is an emerging treatment option for peripheral non-small cell lung... more Stereotactic body radiotherapy is an emerging treatment option for peripheral non-small cell lung cancer in medically inoperable patients. With high dose per fraction radiotherapy, late side effects are of possible concern. In our initial cohort of 42 patients treated with 54 to 60 Gy in three fractions, nine patients have rib fracture. The median dose to rib fracture sites was 46 to 50 Gy, depending on the method of dose calculation. We describe a typical case of poststereotactic radiotherapy rib fracture and present dosimetric analysis of patients with rib fracture.
Journal of Thoracic Oncology, 2007