Matthew Kolar

A Comparison of Two Stereotactic Body Radiation Fractionation Schedules for Medically Inoperable Stage I Non-small Cell Lung Cancer: The Cleveland Clinic Experience

Purpose: To assess the impact of fractionation upon tumor control and toxicity in medically inoperable early stage lung cancer patients treated with stereotactic body radiotherapy. Methods: We reviewed 94 consecutive stereotactic body radiotherapy treatments (86 patients) with medically inoperable stage I non-small cell lung cancer receiving either 50 Gy in five fractions (n = 56) or 60 Gy in three fractions (n = 38) from October 2003 to August 2007. Institutional practice was 10 Gy × 5 before March 1, 2006, when it changed to 20 Gy × 3 to conform to Radiation Therapy Oncology Group 0236 unless otherwise dictated clinically. Results: Median age was 73 years and median Karnofsky performance status 80. A total of 69 lesions were T1, 24 were T2 lung cancer. Median follow-up was 15.3 months. For the 50- and 60-Gy cohorts at 1 year, local control was 97.3% versus 100%, nodal failure 7.3% versus 3.4%, distant metastasis rate 21.8% versus 29.5%, and overall survival 83.1% versus 76.9% (p = 0.68, 0.54, 0.56, and 0.54, respectively). There was no difference in overall survival for patients with histologic (n = 61) compared with radiographic (n = 33) diagnosis. There was no impact of fractionation in the subset of T2 tumors. We observed two cases (2.2%) of clinical grade 2 pneumonitis. Mild late chest wall toxicity (grade 1 or 2) was seen in nine patients (10%) at a median of 8.4 months after treatment and was more common in the 60-Gy group (7 of 38 [18%] versus 2 of 56 [4%], p = 0.028). Conclusions: Local control, overall survival, nodal failure, and distant failure were not affected by fractionation. Chest wall toxicity was more common with 60-Gy group.

Intensity-Modulated Radiotherapy-Based Stereotactic Body Radiotherapy for Medically Inoperable Early-Stage Lung Cancer: Excellent Local Control

PURPOSE To validate the use of stereotactic body radiotherapy (SBRT) using intensity-modulated radiotherapy (IMRT) beams for medically inoperable Stage I lung cancer. METHODS AND MATERIALS From February 2004 to November 2006, a total of 26 patients with 28 lesions received SBRT using a Novalis/BrainLAB system. Immobilization involved a Bodyfix vacuum cushion. A weighted abdominal belt limited respiratory excursion. Computed tomographic simulation images were acquired at rest, full inhalation, and full exhalation and were merged to generate an internal gross tumor volume (ITV). Dose was prescribed to cover the planning target volume (PTV), defined as PTV = ITV + 3-5 mm set-up margin. Heterogeneity corrections were used. Delivery of 50 Gy in five sequential fractions typically used seven nonopposing, noncoplanar beams. Image-guided target verification was provided by BrainLAB-ExacTrac. RESULTS Among the 26 patients, the mean age was 74 years (range, 49-88 years). Of the patients, 50% were male and 50% female. The median Karnofsky performance status was 70 (range, 40-100). The median follow-up was 30.9 months (range, 10.4-51.4 months). Tissue diagnosis was contraindicated in seven patients (26.9%). There were 22 T1 (78.6%) and six T2 (21.4%) tumors. The median conformality index was 1.38 (range, 1.12-1.8). The median heterogeneity index was 1.08 (range, 1.04-1.2). One patient (3.6%) developed acute Grade 3 dyspnea and one patient developed late Grade 2 chest wall pain. Actuarial local control and overall survival at 3 years were 94.4% and 52%, respectively. CONCLUSIONS Use of IMRT-based delivery of SBRT using restriction of tumor motion in medically inoperable lung cancer demonstrates excellent local control and favorable survival.

Failure modes and effects analysis applied to high-dose-rate brachytherapy treatment planning

PURPOSE To apply failure modes and effects analysis to high-dose-rate treatment planning to identify the most likely and significant sources of error in the process. METHODS We have made a list of 25 failure modes grouped into six categories (imaging, catheter reconstruction, dwell position activity, dose points/normalization, optimization/dose, and evaluation). Each mode was rated on a one to five scale for severity, likelihood of occurrence, and probability of escaping detection. An overall ranking was formed from the product of the three scores. The authors assigned scores independently and the resulting rankings were averaged. We also analyzed 44 reported medical events related to high-dose-rate treatment planning listed on the Nuclear Regulatory Commission Web site and compared them with our own rankings. RESULTS Failure modes associated with image sets, catheter reconstruction, indexer length, and incorrect dose points had the highest ranking in our analysis (scores higher than 20). The most often cited failure modes in the Nuclear Regulatory Commission reports examined were indexer length (20/44) and incorrect dose points (6/44). Several of our high-ranking modes are not associated with reported events. CONCLUSION It is a useful exercise to identify failure modes locally and analyze the efficacy of the local quality assurance program. Comparison with nationally reported failures can help direct the local analysis, but the absence or small number of reports for failure modes with a high score may be owing to low detectability. Such modes obviously cannot be ignored.

Intraoperative radiation therapy with the photon radiosurgery system in locally advanced and recurrent rectal cancer: retrospective review of the Cleveland clinic experience

BackgroundPatients with locally advanced or recurrent rectal cancer often require multimodality treatment. Intraoperative radiation therapy (IORT) is a focal approach which aims to improve local control.MethodsWe retrospectively reviewed 42 patients treated with IORT following definitive resection of a locally advanced or recurrent rectal cancer from 2000–2009. All patients were treated with the Intrabeam® Photon Radiosurgery System (PRS). A dose of 5 Gy was prescribed to a depth of 1 cm (surface dose range: 13.4-23.1, median: 14.4 Gy). Median survival times were calculated using Kaplan-Meier analysis.ResultsOf 42 patients, 32 had recurrent disease (76%) while 10 had locally advanced disease (24%). Eighteen patients (43%) had tumors fixed to the sidewall. Margins were positive in 19 patients (45%). Median follow-up after IORT was 22 months (range 0.2-101). Median survival time after IORT was 34 months. The 3-year overall survival rate was 49% (43% for recurrent and 65% for locally advanced patients). Local recurrence was evaluable in 34 patients, of whom 32% failed. The 1-year local recurrence rate was 16%. Distant metastasis was evaluable in 30 patients, of whom 60% failed. The 1-year distant metastasis rate was 32%. No intraoperative complications were attributed to IORT. Median duration of IORT was 35 minutes (range: 14–39). Median discharge time after surgery was 7 days (range: 2–59). Hydronephrosis after IORT occurred in 10 patients (24%), 7 of whom had documented concomitant disease recurrence.ConclusionsThe Intrabeam® PRS appears to be a safe technique for delivering IORT in rectal cancer patients. IORT with PRS marginally increased operative time, and did not appear to prolong hospitalization. Our rates of long-term toxicity, local recurrence, and survival rates compare favorably with published reports of IORT delivery with other methods.

Intraoperative radiotherapy to treat newly diagnosed solitary brain metastasis: initial experience and long-term outcomes

OBJECT The authors assessed the feasibility of intraoperative radiotherapy (IORT) using a portable radiation source to treat newly diagnosed, surgically resected, solitary brain metastasis (BrM). METHODS In a nonrandomized prospective study, 23 patients with histologically confirmed BrM were treated with an Intrabeam device that delivered 14 Gy to a 2-mm depth to the resection cavity during surgery. RESULTS In a 5-year minimum follow-up period, progression-free survival from the time of surgery with simultaneous IORT averaged (± SD) 22 ± 33 months (range 1-96 months), with survival from the time of BrM treatment with surgery+IORT of 30 ± 32 months (range 1-96 months) and overall survival from the time of first cancer diagnosis of 71 ± 64 months (range 4-197 months). For the Graded Prognostic Assessment (GPA), patients with a score of 1.5-2.0 (n = 12) had an average posttreatment survival of 21 ± 26 months (range 1-96 months), those with a score of 2.5-3.0 (n = 7) had an average posttreatment survival of 52 ± 40 months (range 5-94 months), and those with a score of 3.5-4.0 (n = 4) had an average posttreatment survival of 17 ± 12 months (range 4-28 months). A BrM at the treatment site recurred in 7 patients 9 ± 6 months posttreatment, and 5 patients had new but distant BrM 17 ± 3 months after surgery+IORT. Six patients later received whole-brain radiation therapy, 7 patients received radiosurgery, and 2 patients received both treatments. The median Karnofsky Performance Scale scores before and 1 and 3 months after surgery were 80, 90, and 90, respectively; at the time of this writing, 3 patients remain alive with a CNS progression-free survival of > 90 months without additional BrM treatment. CONCLUSIONS The results of this study demonstrate the feasibility of resection combined with IORT at a dose of 14 Gy to a 2-mm peripheral margin to treat a solitary BrM. Local control, distant control, and long-term survival were comparable to those of other commonly used modalities. Surgery combined with IORT seems to be a potential adjunct to patient treatment for CNS involvement by systemic cancer.

Safety and efficacy of iodine-125 permanent prostate brachytherapy in patients with J-pouch anastomosis after total colectomy for ulcerative colitis

PURPOSE To ascertain the safety and efficacy of permanent prostate brachytherapy (PPB) in early prostate cancer patients who have undergone previous total proctocolectomy and J-pouch anastomosis for inflammatory bowel disease. METHODS AND MATERIALS We identified 10 patients with a previous history of prostate cancer and J-pouch anastomosis from our institutional review board-approved database. Seven patients had PPB and 3 had prostatectomy. Only patients treated with PPB were included. Patient records were reviewed to collect data on treatment-related toxicity and oncological outcomes. RESULTS All 7 patients who underwent PPB had low- to intermediate-risk prostate cancer. The mean prostatic volume was 24.40 mL and the average number of iodine-125 seeds implanted was 84. Postimplant dosimetric calculations showed a mean prostate volume receiving 100% of the prescribed dose (V100) of 88.76%, V150 of 45.23%, V200 of 16.79%, radiation dose delivered to 90% of the prostate of 147.89 Gy, volume of ileal pouch receiving 100% of the prescribed dose of 0.164 mL, and volume of ileal pouch receiving 50% of the prescribed dose of 1.38 mL. After a mean follow-up of 19 months, none of the patients had evidence of biochemical failure or clinical failure. There were no long-term genitourinary side effects detected. Two patients had Common Terminology Criteria for Adverse Events version 4.0 grade II gastrointestinal side effects, of which symptoms resolved to baseline in 1 patient, whereas the other patient progressed to chronic active enteritis (pouchitis). CONCLUSION Low- to intermediate-risk prostate cancer patients with J-pouch anastomosis after total colectomy for inflammatory bowel disease are candidates for definitive treatment with PPB. Caution should be exercised while deploying the most posterior row of seeds to minimize enteral pouch radiation doses.

Principles and practice of high-dose rate penile brachytherapy: Planning and delivery techniques

PURPOSE To allow for organ preservation, high-dose rate (HDR) brachytherapy may be used in the treatment of localized penile cancer. Penile cancer is a rare malignancy that accounts for <1% of cancers in men in the United States. The standard treatment for localized disease is partial amputation of the penis. However, patients with T1b or T2 disease <4 cm in maximum dimension and confined to the glans penis may be treated with brachytherapy as an organ-sparing approach. Previous works have described the technique involved for low-dose rate brachytherapy; however, we detail the techniques involved with HDR brachytherapy. METHODS AND MATERIALS Circumcision should precede brachytherapy. Interstitial brachytherapy needles are placed in the operating room under general anesthesia with the goal to allow for appropriate target coverage. Target definition is done via computed tomography-based simulation and planning. Radiation is delivered using a prescription dose of 3840 cGy in 12 fractions twice daily over a course of 6 days. RESULTS Acute toxicities peak upon completion of the radiation therapy and may include dermatitis, sterile urethritis, and adhesions in the urethra. These toxicities are reversible and generally take 2 to 3 months to heal. The two most common and significant late complications of radiation therapy for penile cancer are soft tissue necrosis and meatal stenosis. An increased risk of necrosis has been reported with T3 tumors and higher-volume implants (>30 cm3). Erectile function is generally maintained because the erectile tissues including the penile shaft and corpora have not been irradiated. CONCLUSIONS Organ preservation is feasible using HDR brachytherapy with favorable acute and late toxicities.

Data-driven management using quantitative metric and automatic auditing program (QMAP) improves consistency of radiation oncology processes

PURPOSE Process consistency in planning and delivery of radiation therapy is essential to maintain patient safety and treatment quality and efficiency. Ensuring the timely completion of each critical clinical task is one aspect of process consistency. The purpose of this work is to report our experience in implementing a quantitative metric and automatic auditing program (QMAP) with a goal of improving the timely completion of critical clinical tasks. METHODS AND MATERIALS Based on our clinical electronic medical records system, we developed a software program to automatically capture the completion timestamp of each critical clinical task while providing frequent alerts of potential delinquency. These alerts were directed to designated triage teams within a time window that would offer an opportunity to mitigate the potential for late completion. Since July 2011, 18 metrics were introduced in our clinical workflow. We compared the delinquency rates for 4 selected metrics before the implementation of the metric with the delinquency rate of 2016. One-tailed Student t test was used for statistical analysis RESULTS: With an average of 150 daily patients on treatment at our main campus, the late treatment plan completion rate and late weekly physics check were reduced from 18.2% and 8.9% in 2011 to 4.2% and 0.1% in 2016, respectively (P < .01). The late weekly on-treatment physician visit rate was reduced from 7.2% in 2012 to <1.6% in 2016. The yearly late cone beam computed tomography review rate was reduced from 1.6% in 2011 to <0.1% in 2016. CONCLUSIONS QMAP is effective in reducing late completions of critical tasks, which can positively impact treatment quality and patient safety by reducing the potential for errors resulting from distractions, interruptions, and rush in completion of critical tasks.

SU-F-T-338: Flattening Filter Free Photon Beams Can Achieve the Same Plan Quality as Conventional Flattened Beams for Prostate Radiotherapy

PURPOSE Some modern linear accelerators are equipped with one low energy flat beam and two flattening filter free (FFF) beams at high and low energies. The purpose of this study is to investigate whether the high energy FFF beam can produce the same plan quality as the conventional low energy flat beam, using a volumetric modulated arc (VMAT) technique for prostate patients. METHODS Ten prostate cancer patients were selected with a prescription of 78Gy. For each patient, three plans were created: (a) double arc flat 6MV plan used clinically; (b) double arc 10MV FFF plan; (c) single arc 10MV FFF plan. Each plan was prescribed so that at least 95% of the PTV received the prescription dose. The following dosimetric endpoints were evaluated: volume receiving 78Gy (V78) of the CTV and PTV, PTV conformality index (CI, ratio of prescription isodose volume to the PTV volume), bladder volume receiving 70Gy (V70) and 60Gy (V60), rectum volume receiving 70Gy (V70) and 50Gy (V50), dose to 10cc of the rectum, and volume of both femoral heads receiving 50Gy (V50). Total monitor units for each plan were recorded. RESULTS No significant difference was found for all dosimetric endpoints between all plans (p>0.05). Compared to the 6MV plans, monitor units were higher with the double arc 10MV FFF plans and lower with the single arc 10MV FFF plans, 29% and 4% respectively. CONCLUSION Both single arc and double arc 10MV FFF VMAT can achieve equivalent plan quality as 6MV flat beam double arc treatment plans. With the gantry speed restriction, a high dose rate of 2400MU/min may allow the optimizer to use more MUs than actually needed. Single arc 10MV FFF VMAT plans are a reasonable alternative to double arc 6MV flat beam VMAT plans.

SU-D-214-03: Experience with Using Treatment Volume for Quality Assurance of HDR Treatment Plans

Purpose: To assess the usefulness of treatment volume (V100) in patient specific HDR treatment plan quality assurance. Methods: The Nucletron Plato and Oncentra treatment planning systems were used in this study. Results from both film‐based 2D and CT‐based 3D planning have been included. Plots of time x activity/dose (T*A/D) versus V100 were constructed for various “fixed” geometry systems such as vaginal cylinders (n=167), endobronchial and esophageal tubes, (n=79) and tandem/ring systems (n=352; pt A dosimetry) as well as for larger interstitial volume implants (n=25). For single catheter applicators, plots of V100 as a function of active length (AL) or treating distance (d) were also made. Results: The T*A/D vs V100 plots for the fixed systems above were all very linear (r2 of at least 0.98); a slight improvement in some cases was noted when a second order polynomial was used to fit the data. The volume implant data were best fit with a second order polynomial (r2 = 0.98). For a given treating distance, V100 not surprisingly was a linear function of active length (2.5 to 17 cm) for single or quasi‐single (2 or 3 catheter esophagus) line applicators. We found that V100 values were extremely consistent for a given treating distance and active length (e.g. 36.64 ± 0.45 cm3 for d= 1.5 cm and AL = 4 cm). For tandem/ring applicators, V100 values could achieve similar consistency only if considerable care was taken in defining the catheters. Conclusion: Volume data provide a simple, fast and consistent method of checking new treatment plans against historic data (representative samples of which need to be independently verified). For simple applicators, both the V100 and the value of T*A/D may be used for this comparison.