R.J. Cohen

Esophageal Motion During Radiotherapy: Quantification and Margin Implications

The purpose was to evaluate interfraction and intrafraction esophageal motion in the right-left (RL) and anterior-posterior (AP) directions using computed tomography (CT) in esophageal cancer patients. Eight patients underwent CT simulation and CT-on-rails imaging before and after radiotherapy. Interfraction displacement was defined as differences between pretreatment and simulation images. Intrafraction displacement was defined as differences between pretreatment and posttreatment images. Images were fused using bone registries, adjusted to the carina. The mean, average of the absolute, and range of esophageal motion were calculated in the RL and AP directions, above and below the carina. Thirty-one CT image sets were obtained. The incidence of esophageal interfraction motion > or =5 mm was 24% and > or =10 mm was 3%; intrafraction motion > or =5 mm was 13% and > or =10 mm was 4%. The average RL motion was 1.8 +/- 5.1 mm, favoring leftward movement, and the average AP motion was 0.6 +/- 4.8 mm, favoring posterior movement. Average absolute motion was 4.2 mm or less in the RL and AP directions. Motion was greatest in the RL direction above the carina. Coverage of 95% of esophageal mobility requires 12 mm left, 8 mm right, 10 mm posterior, and 9 mm anterior margins. In all directions, the average of the absolute interfraction and intrafraction displacement was 4.2 mm or less. These results support a 12 mm left, 8 mm right, 10 mm posterior, and 9 mm anterior margin for internal target volume (ITV) and can guide margins for future intensity modulated radiation therapy (IMRT) trials to account for organ motion and set up error in three-dimensional planning.

Biochemical and clinical experience with real-time intraoperatively planned permanent prostate brachytherapy

PURPOSE To evaluate patient characteristics and dosimetric parameters that predict biochemical failure (BCF) after real-time planned low-dose-rate prostate brachytherapy. METHODS From 1998 to 2008, a low-risk cohort by National Comprehensive Cancer Network criteria of 341 men with a median followup of 41.6 months was analyzed. This cohort had a median age of 65.1 years, prostate volume of 35.8cc, and pretreatment prostate-specific antigen of 5.6ng/mL. Patients had predominately Gleason 6 (95.9%) and T1c (81.3%) disease. About 3.6% of the patients received androgen deprivation therapy. Kaplan-Meier and Cox proportional hazards survival analysis methods were used to analyze predictors of BCF (Phoenix definition). RESULTS At 72 months, freedom from BCF was 91.1% (95% confidence interval=85.0-94.8). The median D(90) was 145.9Gy, and the median V(100) was 90.3%. Because of infrequent BCF, the following prostate volume groups were examined: 15-<25, 25-<35, 35-<45, and 45+cc. Of all possible predictors, only small prostate volume (15-<25cc group) was significantly associated with BCF (hazard ratio=8.44, 95% confidence interval=1.82-39.14, p=0.007). Using Kaplan-Meier analysis, time to BCF was also significantly increased in the lowest prostate volume 15-<25cc group with 24.1% failing at 48 months compared with 1.6-5.1% among the other groups. CONCLUSIONS Real-time planned low-dose-rate prostate brachytherapy provides excellent biochemical control as a single-agent treatment for low-risk prostate cancer with 91.1% freedom from BCF at 72 months. Only prostate volume less than 25cc was an independent predictor of BCF.

An intraoperative real-time sleeved seed technique for permanent prostate brachytherapy.

PURPOSE To describe a novel technique that integrates customized sleeved seed production to reduce seed migration using preloaded needles with real-time intraoperative dosimetric planning for patients treated with iodine-125 (I-125) permanent prostate seed implants. METHODS AND MATERIALS Customized seed-spacer sequences were calculated for patients in real time based on an intraoperative transrectal ultrasound-guided volume study. Using a Fox Chase Cancer Center modified Best Iodine-125 seed loader (Best Medical, Springfield, VA), the seeds and spacers were inserted into a hollow suture material (sleeve) and then loaded into the implant needles. Needles were placed sequentially under transrectal ultrasound guidance with sagittal plane visualization of the dropped sleeved seeds. RESULTS This technique was successfully implemented allowing intraoperative planning to be combined with real-time sleeved seed production. CONCLUSIONS The use of sleeves for seeds combined with real-time intraoperative planning allowed for the intraoperative customization of implants with the practical advantages of linked seeds.

Stereotactic Body Radiation Therapy

Stereotactic body radiotherapy (SBRT) is a noninvasive method to deliver high doses of precision radiotherapy to small tumors in the body using novel technologies developed over the last 15 years. Since its inception, this approach was initially developed to shorten therapy for patients with severe limitations making more prolonged courses of radiation a significant burden but investigators have discovered that this treatment not only is more efficacious than conventional therapy but also has lower side effect profile. In fact, the outcomes are so favorable that several cooperative groups are now challenging the paradigm that surgery is the standard of care for lung cancer. Inside this chapter, the authors paint the picture of the current landscape of SBRT and the important steps needed to consider as a clinical SBRT program is developed. This includes the definition of target volumes, the mechanism of action, patient selection, the appropriate use of immobilization, motion management, image guidance, and simulation. In addition, the last several sections try to go through the clinical data for the most commonly treated subsites with SBRT and discuss the potential future.

Identifying Patients Who May Be Candidates for a Clinical Trial of Salvage Accelerated Partial Breast Irradiation after Previous Whole Breast Irradiation

Background and Objectives. Accelerated partial breast irradiation (APBI) has been proposed as an alternative to salvage mastectomy for patients with ipsilateral breast tumor recurrence (IBTR) after prior breast conservation. We studied factors that are associated with a more favorable local recurrence profile that could make certain patients eligible for APBI. Methods. Between 1980 and 2005, 157 Stage 0–II breast cancer patients had an IBTR treated by mastectomy. Clinical and pathological features were analyzed to identify factors associated with favorable IBTR defined as unifocal DCIS or T1 ≤ 2 cm, without skin involvement, and >2 year interval from initial treatment. Results. Median followup was 140 months and time to recurrence was 73 months. Clinical stage distribution at recurrence was DCIS in 32 pts (20%), T1 in 90 pts (57%), T2 in 14 pts (9%), T3 in 4 pts (3%), and T4 in 9 pts (6%). IBTR was classified as favorable in 71%. Clinical stage of IBTR predicted for pathologic stage –95% of patients with clinical T1 IBTR had pathologic T1 disease at salvage mastectomy (P < 0.0001). Conclusions. Clinical stage at presentation strongly correlated with pathologic stage at mastectomy. More than 70% of recurrences were favorable and may be appropriate candidates for salvage APBI trials.

Original article: Esophageal motion during radiotherapy: quantification and margin implications: Esophageal motion during radiotherapy

The purpose was to evaluate interfraction and intrafraction esophageal motion in the right-left (RL) and anterior-posterior (AP) directions using computed tomography (CT) in esophageal cancer patients. Eight patients underwent CT simulation and CT-on-rails imaging before and after radiotherapy. Interfraction displacement was defined as differences between pretreatment and simulation images. Intrafraction displacement was defined as differences between pretreatment and posttreatment images. Images were fused using bone registries, adjusted to the carina. The mean, average of the absolute, and range of esophageal motion were calculated in the RL and AP directions, above and below the carina. Thirty-one CT image sets were obtained. The incidence of esophageal interfraction motion > or =5 mm was 24% and > or =10 mm was 3%; intrafraction motion > or =5 mm was 13% and > or =10 mm was 4%. The average RL motion was 1.8 +/- 5.1 mm, favoring leftward movement, and the average AP motion was 0.6 +/- 4.8 mm, favoring posterior movement. Average absolute motion was 4.2 mm or less in the RL and AP directions. Motion was greatest in the RL direction above the carina. Coverage of 95% of esophageal mobility requires 12 mm left, 8 mm right, 10 mm posterior, and 9 mm anterior margins. In all directions, the average of the absolute interfraction and intrafraction displacement was 4.2 mm or less. These results support a 12 mm left, 8 mm right, 10 mm posterior, and 9 mm anterior margin for internal target volume (ITV) and can guide margins for future intensity modulated radiation therapy (IMRT) trials to account for organ motion and set up error in three-dimensional planning.

Original article: Esophageal motion during radiotherapy: quantification and margin implications

The purpose was to evaluate interfraction and intrafraction esophageal motion in the right-left (RL) and anterior-posterior (AP) directions using computed tomography (CT) in esophageal cancer patients. Eight patients underwent CT simulation and CT-on-rails imaging before and after radiotherapy. Interfraction displacement was defined as differences between pretreatment and simulation images. Intrafraction displacement was defined as differences between pretreatment and posttreatment images. Images were fused using bone registries, adjusted to the carina. The mean, average of the absolute, and range of esophageal motion were calculated in the RL and AP directions, above and below the carina. Thirty-one CT image sets were obtained. The incidence of esophageal interfraction motion > or =5 mm was 24% and > or =10 mm was 3%; intrafraction motion > or =5 mm was 13% and > or =10 mm was 4%. The average RL motion was 1.8 +/- 5.1 mm, favoring leftward movement, and the average AP motion was 0.6 +/- 4.8 mm, favoring posterior movement. Average absolute motion was 4.2 mm or less in the RL and AP directions. Motion was greatest in the RL direction above the carina. Coverage of 95% of esophageal mobility requires 12 mm left, 8 mm right, 10 mm posterior, and 9 mm anterior margins. In all directions, the average of the absolute interfraction and intrafraction displacement was 4.2 mm or less. These results support a 12 mm left, 8 mm right, 10 mm posterior, and 9 mm anterior margin for internal target volume (ITV) and can guide margins for future intensity modulated radiation therapy (IMRT) trials to account for organ motion and set up error in three-dimensional planning.

Effect of reduction mammoplasty on acute radiation side effects and use of lumpectomy cavity boosts

PURPOSE Reduction mammoplasty (RM) during breast-conserving surgery is popular among women with large-volume breasts because it reduces redundant breast folds and may decrease skin-related morbidity from radiation therapy. However, RM may obscure the lumpectomy cavity (LC) and pose challenges to administering an LC boost, potentially affecting local control. We investigated the impact of RM on acute side effects and use of LC boosts. METHODS AND MATERIALS The records of 645 consecutive women treated with whole-breast irradiation at an urban university and 2 community practices between January 2012 and December 2014 were reviewed on an institutional review board-approved study. The primary endpoint was grade ≥3 radiation dermatitis; the secondary endpoint was use of LC boost. Student 2-sample t tests, Pearson χ2 tests, Fisher exact tests, and univariate and multivariable logistic regression analyses were performed. RESULTS Forty-three (7%) RMs were performed in 650 treated breasts. No significant differences in grade 3 toxicities were identified among RM and non-RM patients. LC boost was delivered to 474 breasts. Fewer (16/43) RM patients received LC boosts compared with non-RM patients (458/607), P = .0001. RM patients were more likely to have neoadjuvant chemotherapy, stage III or multifocal disease, higher body mass index, larger planning treatment volumes, and conventional fractionation (P < .05). CONCLUSIONS RM was associated with decreased use of LC boost without significant differences in acute toxicities. Further investigation to delineate LCs in patients undergoing RM or identify alternative strategies for delivering LC dose is needed.

What is the impact of reduction mammoplasty for women undergoing breast-conserving surgery for breast cancer?

49 Background: Reduction mammoplasty (RM) at time of breast conserving surgery (BCS) is an increasingly popular procedure that reduces redundant breast folds and skin toxicity from whole breast irradiation (WBI). However, the tissue manipulation may obscure the lumpectomy cavity (LC) and hinder the ability to deliver a radiation boost to the LC, potentially impacting local control. We studied the impact of RM on acute radiation side effects and the use of LC boost. METHODS From Jan 2012 to Dec 2014, 652 consecutive women with DCIS or Stage I-III invasive cancer were treated with curative intent BCS and WBI at an urban university and 2 community practices. We reviewed the charts on an IRB-approved study with the primary endpoint of ≥ grade 3 radiation dermatitis scored via the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0. Secondary endpoint was the use of LC boost. Tested variables included age, race, body mass index, menopausal status, multi-focal disease, stage, tumor grade, receptor status, chemotherapy administered, specimen volume, 3D or intensity modulated radiation, fractionation, nodal irradiation, and planning treatment volume (PTV). Students t-tests and Pearsons chi-square tests were utilized. RESULTS Forty-three (7%) of 652 patients underwent RM. Larger volumes of tissue were removed from the RM patients (median 366.5 g v 35.3 g, P= 0.0001). No grade 4 toxicities and few (2-3%) grade 3 toxicities were seen, P= 1.00. Narcotic use was similar (4-5%), P= 0.70. A LC boost was used in 476 (73%) patients; RM significantly decreased the use of a boost [16/43 (37%) v 460/609 (76%)], P= 0.0001. RM patients were more likely to have neoadjuvant chemotherapy, stage III or multi-focal disease, higher BMI, nodal irradiation, and conventional fractionation (P< 0.05). Subgroup analysis of the patients with available PTVs (67%) revealed similar volumes (P= 0.16). CONCLUSIONS RM was associated with a decrease in the use of LC boost without significant differences in acute toxicities; however, the result is not surprising given that PTVs were similar. Further investigation is needed to better delineate LCs in patients undergoing RM to increase the use of LC boosts.

Pretreatment SBRT Imaging Correlates Equally Well With Multiphase 4DCT and Averaging of 4DCT Simulation

locations. Simulations of combined setup errors showed an increased cord dose sensitivity to rotational errors when combined with translational error. Conclusions: This study is the most detailed analysis of the effect of rotational setup errors in isolation, and when combined with translational setup errors, on the spinal cord dose distribution and mapped cord surface dose. The effects were more significant with greater distance between the isocenter and the 90% isodose on the PRV surface. A linear model was designed to predict dosimetric impact of rotational setup error which can be used to prospectively identify treatment plans that are more likely to be sensitive to even minor rotational setup errors. Author Disclosure: A. Fotouhi Ghiam: None. H. Keller: None. M. Sharpe: None. B. Millar: None. P. Chung: None. D. Jaffray: None. A. Sahgal: None. D. Letourneau: None.