Postoperative IMRT Research Articles

Surgical Treatment Intensification for HPV-Negative Oropharyngeal Squamous Cell Carcinoma (OSCC)

Surgical Treatment Intensification for HPV-Negative Oropharyngeal Squamous Cell Carcinoma (OSCC)

SU-E-T-579: Dosimetric Benefits of Online Adaptive Replanning for Post-Operative Radiation Therapy of Prostate Bed.

To demonstrate the dosimetric benefits of using an online adaptive replanning scheme to address interfractional variations in radiotherapy of prostate bed. We have previously developed an online adaptive replanning tool (RealART, Prowess Inc.) aiming to address interfractional variations including organ deformation and rotation. Using this tool, we analyzed a total of 102 daily pre-treatment CTs acquired using an in-room CT (CTVision, Siemens) for 10 patients treated with post-operative IMRT of prostate bed. The PTV was assumed to be the volume enclosed by the 95% prescription isodose surface generated for the conventional four field box. On each daily CT set, contours of the PTV, rectum and bladder were generated by populating the planning contours using an auto-segmentation tool based on deformable registration (ABAS, Elekta) with manual editing. Four plans were generated and compared: (1) IGRT (repositioning) plan by copying the original plan with aligning the anterior rectal wall from the daily CT to that of the planning CT, (2) IGRT plan by copying the original plan with aligning the surgical clips, (3) online adaptive plan by tailoring the original plan to conform to the anatomy of the day, and (4) a new plan re- optimized based on the daily anatomy. The adaptive and re- optimization plans are in general superior than the two repositioning plans in terms of both target coverage and critical structure sparing. For example, the averages of dose volume quantities for all daily CTs are: rectum V45Gy 55.7±18.0% (one standard deviation), 57.3±17.5%, 48.2±11.8%, 42.5±9.6%; rectum V60Gy 31.8±20.3%, 34.0±16.6%, 22.6±9.7%, 16.5±7.4%; bladder V45Gy 30.0±11.9%, 39.5±24.2%, 37.6±16.8%, 36.5±16.2%; bladder V60Gy 17.4±9.2%, 25.4±18.1%, 24.7±12.7%, 23.9±12.0%; PTV V100 81.9±16.6%, 88.7±7.9%, 92.9±4.6%, and 94.6±2.4% for the above (1)-(4) plans, respectively. The online adaptive replanning scheme is effective to account for interfractional variations in post-operative radiotherapy of prostate bed. This work is supported partially by MCW Cancer Center Fotsch Foundation.

Desmoplastic Small Round Cell Tumor: Current Management and Recent Findings

Desmoplastic small round cell tumor (DSRCT) is a rare and highly aggressive mesenchymal tumor that develops in the abdominal cavity of young men adults. Patients typically present with symptoms of abdominal sarcomatosis. Diagnosis is based on histological analysis of biopsies which typically show small round blue cells in nests separated by an abundant desmoplastic stroma. DSRCT is associated with a unique chromosomal translocation t(11:22) (p 13; q 12) that involves the EWSR1 and WT1 genes. The prognosis is particularly poor; median survival ranges from 17 to 25 months, largely due to the presentation of the majority of patients with metastatic disease. Management of DSRCT remains challenging and current schemes lack a significant cure rate despite the use of aggressive treatments such as polychemotherapy, debulking surgery and whole abdominal radiation. Several methods are being evaluated to improve survival: addition of chemotherapy and targeted therapies to standard neoadjuvant protocol, completion of surgical resection with HIPEC, postoperative IMRT, treatment of hepatic metastases with [90Y]Yttrium microsphere liver embolization.

Postoperative IMRT following Surgery for Oral Cavity Squamous Cell Carcinoma: Patterns of Failure

Postoperative IMRT following Surgery for Oral Cavity Squamous Cell Carcinoma: Patterns of Failure

Postoperative IMRT for Cervical and Endometrial Cancer

Postoperative IMRT for Cervical and Endometrial Cancer

Dose–volume analysis of locoregional recurrences in head and neck IMRT, as determined by deformable registration: A prospective multi-institutional trial

Background and purpose Although IMRT for head and neck cancer is widely accepted, the implications of sparing normal tissue immediately adjacent to target volumes are not well known. Materials and methods Between 2002 and 2007, 124 patients with head and neck cancer were treated with surgery and postoperative IMRT ( n = 79) or definitive RT ( n = 45). Locoregional recurrences were analyzed for location relative to target volumes, and dosimetry. Results With a median follow-up of 26.1 months, a total of 16 locoregional recurrences were observed. The five-year actuarial locoregional disease-free survival was 82% [95% CI, 72–90%]. Analysis of 18 distinct sites of locoregional failure revealed that five of these failures were within the high dose clinical target volume (CTV), nine failures were at the margin of the CTV, and four recurrences were outside the CTV. The mean dose delivered to these recurrent volumes was 63.1 Gy [range: 57–68 Gy], while the mean dose to the coolest 1 cc within each recurrence was 60.0 Gy [range: 51–67 Gy]. There were two periparotid recurrences observed. Conclusions We observed excellent locoregional control rates overall. The majority of recurrences occur within high dose regions of the neck and not near the spared parotid glands.

Outcomes of p16 Positive Oropharyngeal Squamous Cell Carcinoma Treated with Postoperative Adjuvant IMRT +/- Chemotherapy: A Retrospective Analysis

Recent data has shown that for oropharyngeal squamous cell carcinoma (OPSCC), p16 positivity (p16+), a surrogate for HPV, portends a better prognosis. At Washington University, the most frequent approach for OPSCC is minimally invasive transoral laser microsurgery (TLM) with adjuvant radiotherapy (RT) or chemoradiotherapy (CRT). This retrospective review compares outcomes for OPSCC p16+ patients treated with adjuvant RT or CRT.

Hematologic Toxicity on RTOG 0418: A Phase II Study of Post-operative IMRT for Gynecologic Cancer

Purpose Intensity modulated radiation therapy (IMRT), compared with conventional 4-field treatment, can reduce the volume of bone marrow irradiated. Pelvic bone marrow sparing has produced a clinically significant reduction in hematologic toxicity (HT). This analysis investigated HT in RTOG 0418, a prospective study to test the feasibility of delivering postoperative IMRT for cervical and endometrial cancer in a multi-institutional setting.

Tomotherapy-based IMRT after limb-preserving surgery for extremity soft-tissue sarcomas: Planning, verification, and treatment times.

e20514 Background: Radiotherapy improves local control after limb-sparing surgery for soft tissue sarcomas (STS). IMRT can optimize treatment dose conformity compared to standard conformal therapy. At the Northern Centre for Cancer Care we prescribe 60Gy. Until 2009 this was delivered using conventional Linac-based 3D conformal RT. Since installation of a tomotherapy unit, because of the potential long- term clinical advantages, selected sarcoma patients have been treated with postoperative IMRT. Tomotherapy necessitates longer planning, verification, and treatment times. These have been analysed to assess impact on resources. Methods: Six such patients have now been treated with IMRT. Tomotherapy planning requires more volume definition of organs at risk and “help structures” and processing for dose optimization. Times have been recorded within the implementation phase. Conventional Linac verification uses portal imaging daily for three days. Shifts are made to exclude systematic error, if tolerance is e...

8043 Small bowel volume in postoperative IMRT for endometiral cancer and acute lower GI toxicity: separate loops vs. bowel space

8043 Small bowel volume in postoperative IMRT for endometiral cancer and acute lower GI toxicity: separate loops vs. bowel space

Outcome in recurrent head neck cancer treated with salvage-IMRT

BackgroundRecurrent head neck cancer (rHNC) is a known unfavourable prognostic condition.The purpose of this work was to analyse our rHNC subgroup treated with salvage-intensity modulated radiation therapy (IMRT) for curable recurrence after initial surgery alone.PatientsBetween 4/2003–9/2008, 44 patients with squamous cell rHNC were referred for IMRT, mean/median 33/21 (3–144) months after initial surgery. None had prior head neck radiation. 41% underwent definitive, 59% postoperative IMRT (66–72.6 Gy). 70% had simultaneous chemotherapy.MethodsRetrospective analysis of the outcome following salvage IMRT in rHNC patients was performed.ResultsAfter mean/median 25/21 months (3–67), 22/44 (50%) patients were alive with no disease; 4 (9%) were alive with disease. 18 patients (41%) died of disease. Kaplan Meier 2-year disease specific survival (DSS), disease free survival (DFS), local and nodal control rates of the cohort were 59/49/56 and 68%, respectively.Known risk factors (advanced initial pTN, marginal initial resection, multiple recurrences) showed no significant outcome differences. Risk factors and the presence of macroscopic recurrence gross tumor volume (rGTV) in oral cavity patients vs others resulted in statistically significantly lower DSS (30 vs 70% at 2 years, p = 0.03). With respect to the assessed unfavourable outcome following salvage treatment, numbers needed to treat to avoid one recurrence with initial postoperative IMRT have, in addition, been calculated.ConclusionA low salvage rate of only ~50% at 2 years was found. Calculated numbers of patients needed to treat with postoperative radiation after initial surgery, in order to avoid recurrence and tumor-specific death, suggest a rather generous use of adjuvant irradiation, usually with simultaneous chemotherapy.

Postoperative IMRT in head and neck cancer

BackgroundAim of this work was to assess loco-regional disease control in head and neck cancer (HNC) patients treated with postoperative intensity modulated radiation therapy (pIMRT). For comparative purposes, risk features of our series have been analysed with respect to histopathologic adverse factors. Results were compared with an own historic conventional radiation (3DCRT) series, and with 3DCRT and pIMRT data from other centres.Between January 2002 and August 2006, 71 patients were consecutively treated with pIMRT for a squamous cell carcinoma (SCC) of the oropharynx (32), oral cavity (22), hypopharynx (7), larynx (6), paranasal sinus (3), and an unknown primary, respectively. Mean and median follow up was 19 months (2–48), and 17.6 months. 83% were treated with IMRT-chemotherapy. Mean prescribed dose was 66.3 Gy (60–70), delivered with doses per fraction of 2–2.3 Gy, respectively.Results2-year local, nodal, and distant control rates were 95%, 91%, and 96%, disease free and overall survival 90% and 83%, respectively. The corresponding survival rates for the subgroup of patients with a follow up time >12 months (n = 43) were 98%, 95%, 98%, 93%, and 88%, respectively. Distribution according to histopathologic risk features revealed 15% and 85% patients with intermediate and high risk, respectively. All loco-regional events occurred in the high risk subgroup.ConclusionSurgery followed by postoperative IMRT in patients with substantial risk for recurrence resulted in high loco-regional tumor control rates compared with large prospective 3DCRT trials.

2415: Exquisite Sparing of Contralateral Vision in Patients With Advanced Orbital Cancer Treated With Exenteration Followed by Post-Operative IMRT

2415: Exquisite Sparing of Contralateral Vision in Patients With Advanced Orbital Cancer Treated With Exenteration Followed by Post-Operative IMRT

2277: Acute Toxicity Assessment of a Single Institution Series of Prostate Cancer Patients Treated With Pelvic Intensity Modulated Radiation Therapy With Synchronous Integrated Boost to the Prostate or Prostate Bed

We investigated the feasibility of delivering elective pelvic nodal RT combined with a hypofractionated RT regimen to the primary site by employing IMRT with a synchronous integrated boost (SIB) for patients with intermediate to high-risk prostate cancer. We analyzed acute toxicity of SIB IMRT in patients treated either primarily for prostate cancer or with post-operative or salvage RT following prostatectomy. For primary treatment, the prostate planning target volume (PTVprostate) was the prostate plus a 5 mm posterior margin and 1 cm margin in other directions; the nodal PTV (PTVnodes) included the internal, external, and lower common iliac vessels plus a 1 cm circumferential margin. SIB IMRT plans were designed to deliver 70 Gy to the PTVprostate in 28 fractions (2.5 Gy/fraction) while simultaneously delivering 50.4 Gy to the PTVnodes. Post-operative or salvage SIB IMRT included a dose of 64 Gy in 32 fractions to the PTVpost-op, here defined as the prostate bed plus a 1 cm margin, while simultaneously delivering 54.4 Gy to the PTVnodes. The NCIC CTCAE v3.0 was employed to score toxicity. Twenty-seven patients (18 definitive, 5 adjuvant, 4 salvage) were treated between early 2004 and late 2005. The median age at the beginning of treatment was 63 years (range 53–77). Twenty-two out of 27 patients received androgen suppression as a component of treatment, including all patients in the primary RT cohort. Twenty-six out of 27 patients received treatment as prescribed, with 1 patient discontinuing radiation one fraction prior to completion due to a medical problem unrelated to his treatment. Median follow-up of all patients was 9 months (3–19 months). The incidence of any acute grade 1 or 2 event was 96%. The most common acute event was urinary frequency/urgency, which occurred in 81% of patients (67% grade 1, 14% grade 2). Acute diarrhea occurred in 56% of patients (37% grade 1, 15% grade 2, 4% grade 3). The incidence of any grade 3 or higher acute toxicity was 4% (1/27); that patient experienced severe diarrhea while on treatment, but was found to have clostridium difficile colitis, and his symptoms improved rapidly on antibiotics. Pelvic IMRT with synchronous integrated boost to the prostate/prostate bed for high-risk prostate cancer, either given in the primary or post-operative/salvage setting, was acutely well tolerated in our series of patients. Additional follow-up is necessary to ensure that no unexpected late toxicity occurs. SIB IMRT to the pelvis combines elective nodal RT and hypofractionation to the primary and warrants further study in a clinical trial setting.

185 Developing a program for postoperative IMRT in mesothelioma patients following pleurectomy plus phototherapy

185 Developing a program for postoperative IMRT in mesothelioma patients following pleurectomy plus phototherapy

Quality of life assesment in head and neck cancer patients treated with definitive or postoperative IMRT

Quality of life assesment in head and neck cancer patients treated with definitive or postoperative IMRT