Comparison study of intensity modulated arc therapy using single or multiple arcs to intensity modulated radiation therapy for high-risk prostate cancer

Ashamalla, Hani,Tejwani, Ajay,Parameritis, Ioannis,Swamy, Uma,Luo, Pei Ching,Guirguis, Adel,Lavaf, Amir The Korean Society for Radiation Oncology 2013 Radiation Oncology Journal Vol.31 No.2

Purpose: Intensity modulated arc therapy (IMAT) is a form of intensity modulated radiation therapy (IMRT) that delivers dose in single or multiple arcs. We compared IMRT plans versus single-arc field (1ARC) and multi-arc fields (3ARC) IMAT plans in high-risk prostate cancer. Materials and Methods: Sixteen patients were studied. Prostate ($PTV_P$), right pelvic ($PTV_{RtLN}$) and left pelvic lymph nodes ($PTV_{LtLN}$), and organs at risk were contoured. $PTV_P$, $PTV_{RtLN}$, and $PTV_{LtLN}$ received 50.40 Gy followed by a boost to $PTV_B$ of 28.80 Gy. Three plans were per patient generated: IMRT, 1ARC, and 3ARC. We recorded the dose to the PTV, the mean dose ($D_{MEAN}$) to the organs at risk, and volume covered by the 50% isodose. Efficiency was evaluated by monitor units (MU) and beam on time (BOT). Conformity index (CI), Paddick gradient index, and homogeneity index (HI) were also calculated. Results: Average Radiation Therapy Oncology Group CI was 1.17, 1.20, and 1.15 for IMRT, 1ARC, and 3ARC, respectively. The plans' HI were within 1% of each other. The $D_{MEAN}$ of bladder was within 2% of each other. The rectum $D_{MEAN}$ in IMRT plans was 10% lower dose than the arc plans (p < 0.0001). The GI of the 3ARC was superior to IMRT by 27.4% (p = 0.006). The average MU was highest in the IMRT plans (1686) versus 1ARC (575) versus 3ARC (1079). The average BOT was 6 minutes for IMRT compared to 1.3 and 2.9 for 1ARC and 3ARC IMAT (p < 0.05). Conclusion: For high-risk prostate cancer, IMAT may offer a favorable dose gradient profile, conformity, MU and BOT compared to IMRT.

Comparison study of intensity modulated arc therapy using single or multiple arcs to intensity modulated radiation therapy for high-risk prostate cancer

Hani Ashamalla,Ajay Tejwani,Ioannis Parameritis,Uma Swamy,Pei Ching Luo,Adel Guirguis,Amir Lavaf 대한방사선종양학회 2013 Radiation Oncology Journal Vol.31 No.2

Purpose: Intensity modulated arc therapy (IMAT) is a form of intensity modulated radiation therapy (IMRT) that delivers dose in single or multiple arcs. We compared IMRT plans versus single-arc field (1ARC) and multi-arc fields (3ARC) IMAT plans in high-risk prostate cancer. Materials and Methods: Sixteen patients were studied. Prostate (PTV_P), right pelvic (PTV_RtLN) and left pelvic lymph nodes (PTV_LtLN), and organs at risk were contoured. PTV_P, PTV_RtLN, and PTV_LtLN received 50.40 Gy followed by a boost to PTV_B of 28.80 Gy. Three plans were per patient generated: IMRT, 1ARC, and 3ARC. We recorded the dose to the PTV, the mean dose (D_MEAN) to the organs at risk, and volume covered by the 50% isodose. Efficiency was evaluated by monitor units (MU) and beam on time (BOT). Conformity index (CI), Paddick gradient index, and homogeneity index (HI) were also calculated. Results: Average Radiation Therapy Oncology Group CI was 1.17, 1.20, and 1.15 for IMRT, 1ARC, and 3ARC, respectively. The plans’ HI were within 1% of each other. The D_MEAN of bladder was within 2% of each other. The rectum D_MEAN in IMRT plans was 10% lower dose than the arc plans (p < 0.0001). The GI of the 3ARC was superior to IMRT by 27.4% (p = 0.006). The average MU was highest in the IMRT plans (1686) versus 1ARC (575) versus 3ARC (1079). The average BOT was 6 minutes for IMRT compared to 1.3 and 2.9 for 1ARC and 3ARC IMAT (p < 0.05). Conclusion: For high-risk prostate cancer, IMAT may offer a favorable dose gradient profile, conformity, MU and BOT compared to IMRT.

The incidence of pelvic and para-aortic lymph node metastasis in uterine papillary serous and clear cell carcinoma according to the SEER registry

Malcolm D. Mattes, MD,Jennifer C. Lee,Daniel J. Metzger,Hani Ashamalla,Evangelia Katsoulakis 대한부인종양학회 2015 Journal of Gynecologic Oncology Vol.26 No.1

Objective: In this study we utilized the Surveillance, Epidemiology and End-Results (SEER) registry to identify risk factors for lymphatic spread and determine the incidence of pelvic and para-aortic lymph node metastases in patients with uterine papillary serous carcinoma (UPSC) and uterine clear cell carcinoma (UCCC) who underwent complete surgical staging and lymph node dissection. Methods: Nine hundred seventy-two eligible patients diagnosed between 1998 to 2009 with International Federation of Gynecology and Obstetrics (FIGO) 1988 stage IA-IVA UPSC (n=685) or UCCC (n=287) were identified for analysis. Binomial logistic regression was used to determine risk factors for lymph node metastasis, with the incidence of pelvic and para-aortic lymph node metastases reported for each FIGO primary tumor stage. The Cox proportional hazards regression model was used to determine factors associated with overall survival. Results: FIGO primary tumor stage was the only independent risk factor for lymph node metastasis (p<0.01). The incidence of pelvis-only and para-aortic lymph node involvement according to the FIGO primary tumor stage were as follows: IA (2.3%/3.8%), IB (7.5%/5.2%), IC (22.5%/16.9%), IIA (20.8%/13.2%), IIB (25.7%/14.9%), and III/IV (25.7%/24.3%). Prognostic factors for overall survival included lymph node involvement (hazard ratio [HR], 1.42; 95% confidence interval [CI], 1.09 to 1.85; p<0.01), patient age >60 years (HR, 1.70; 95% CI, 1.21 to 2.41; p<0.01), and advanced FIGO primary tumor stage (p<0.01). Tumor grade, histologic subtype, and patient race did not predict for either lymph node metastasis or overall survival. Conclusion: There is a high incidence of both pelvic and para-aortic lymph node metastases for FIGO stages IC and above uterine papillary serous and clear cell carcinomas, suggesting a potential role for lymph node-directed therapy for these patients.

Breast Cancer Subtype as a Predictor of Lymph Node Metastasis according to the SEER Registry

Malcolm D. Mattes,Jay K. Bhatia,Daniel Metzger,Hani Ashamalla,Evangelia Katsoulakis 한국유방암학회 2015 Journal of breast cancer Vol.18 No.2

Purpose: Breast cancer subtype correlates with response to systemic therapy and overall survival (OS), but its impact on lymphatic spread is incompletely understood. In this study, we used the Surveillance, Epidemiology, and End Results registry to assess whether the subtype can predict the presence of nodal metastasis or advanced nodal stage in breast cancer. Methods: A total of 7,274 eligible patients diagnosed with T1-3 infiltrating ductal carcinoma with known estrogen or progesterone hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status, who underwent surgical excision of the primary tumor and pathologic lymph node evaluation, were included in this analysis. Patients were categorized into four breast cancer subtypes: HR+/HER2−; HR+/HER2+; HR−/HER2+; and HR−/HER2−. Binary logistic regression analysis was used to determine whether breast cancer subtype, tumor size, tumor grade, patient race, and patient age at diagnosis are independently predictive of lymph node positivity or advanced nodal stage. The Pearson chi-square test was used to determine whether progesterone receptor (PR) status had an impact on the incidence of lymph node positivity in estrogen receptor (ER) positive patients. Results: Independent predictors of nodal positivity included breast cancer subtype (p=0.040), tumor size (p<0.001), tumor grade (p<0.001), and patient age (p<0.001), whereas only tumor size (p<0.001), grade (p=0.001), and patient age (p=0.005) predicted advanced nodal stage. Triple-negative cancers had a significantly lower risk of nodal positivity than the HR+/HER2− subtype (odds ratio, 0.686; p=0.004), but no other significant differences between subtypes were observed. There was also no difference in lymph node positivity between PR+ and PR− tumors amongst ER+/HER2− (p=0.228) or ER+/HER2+ tumors (p=0.713). Conclusion: The HR+/HER2− breast cancer subtype has a higher rate of lymph node involvement at diagnosis than the triple-negative subtype. These findings may play a role in guiding regional management considerations if confirmed in further studies.

A predictive model to guide management of the overlap region between target volume and organs at risk in prostate cancer volumetric modulated arc therapy

Mattes, Malcolm D.,Lee, Jennifer C.,Elnaiem, Sara,Guirguis, Adel,Ikoro, N.C.,Ashamalla, Hani The Korean Society for Radiation Oncology 2014 Radiation Oncology Journal Vol.32 No.1

Purpose: The goal of this study is to determine whether the magnitude of overlap between planning target volume (PTV) and rectum ($Rectum_{overlap}$) or PTV and bladder ($Bladder_{overlap}$) in prostate cancer volumetric-modulated arc therapy (VMAT) is predictive of the dose-volume relationships achieved after optimization, and to identify predictive equations and cutoff values using these overlap volumes beyond which the Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC) dose-volume constraints are unlikely to be met. Materials and Methods: Fifty-seven patients with prostate cancer underwent VMAT planning using identical optimization conditions and normalization. The PTV (for the 50.4 Gy primary plan and 30.6 Gy boost plan) included 5 to 10 mm margins around the prostate and seminal vesicles. Pearson correlations, linear regression analyses, and receiver operating characteristic (ROC) curves were used to correlate the percentage overlap with dose-volume parameters. Results: The percentage $Rectum_{overlap}$ and $Bladder_{overlap}$ correlated with sparing of that organ but minimally impacted other dose-volume parameters, predicted the primary plan rectum $V_{45}$ and bladder $V_{50}$ with $R^2$ = 0.78 and $R^2$ = 0.83, respectively, and predicted the boost plan rectum $V_{30}$ and bladder $V_{30}$ with $R^2$ = 0.53 and $R^2$ = 0.81, respectively. The optimal cutoff value of boost $Rectum_{overlap}$ to predict rectum $V_{75}$ >15% was 3.5% (sensitivity 100%, specificity 94%, p < 0.01), and the optimal cutoff value of boost $Bladder_{overlap}$ to predict bladder $V_{80}$ >10% was 5.0% (sensitivity 83%, specificity 100%, p < 0.01). Conclusion: The degree of overlap between PTV and bladder or rectum can be used to accurately guide physicians on the use of interventions to limit the extent of the overlap region prior to optimization.

A predictive model to guide management of the overlap region between target volume and organs at risk in prostate cancer volumetric modulated arc therapy

Malcolm D,Mattes,Jennifer C,Lee,Sara Elnaiem,Adel Guirguis,N,C,Ikoro,Hani Ashamalla 대한방사선종양학회 2014 Radiation Oncology Journal Vol.32 No.1

Purpose: The goal of this study is to determine whether the magnitude of overlap between planning target volume (PTV) and rectum (Rectumoverlap) or PTV and bladder (Bladderoverlap) in prostate cancer volumetric-modulated arc therapy (VMAT) is predictive of the dose-volume relationships achieved after optimization, and to identify predictive equations and cutoff values using these overlap volumes beyond which the Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC) dose-volume constraints are unlikely to be met. Materials and Methods: Fifty-seven patients with prostate cancer underwent VMAT planning using identical optimization conditions and normalization. The PTV (for the 50.4 Gy primary plan and 30.6 Gy boost plan) included 5 to 10 mm margins around the prostate and seminal vesicles. Pearson correlations, linear regression analyses, and receiver operating characteristic (ROC) curves were used to correlate the percentage overlap with dose-volume parameters. Results: The percentage Rectumoverlap and Bladderoverlap correlated with sparing of that organ but minimally impacted other dose-volume parameters, predicted the primary plan rectum V45 and bladder V50 with R2 = 0.78 and R2 = 0.83, respectively, and predicted the boost plan rectum V30 and bladder V30 with R2 = 0.53 and R2 = 0.81, respectively. The optimal cutoff value of boost Rectumoverlap to predict rectum V75 >15% was 3.5% (sensitivity 100%, specificity 94%, p < 0.01), and the optimal cutoff value of boost Bladderoverlap to predict bladder V80 >10% was 5.0% (sensitivity 83%, specificity 100%, p < 0.01). Conclusion: The degree of overlap between PTV and bladder or rectum can be used to accurately guide physicians on the use of interventions to limit the extent of the overlap region prior to optimization.