Tumor Treating Fields (TTFields) for Newly Diagnosed Glioblastoma in the Real World: A Systematic Review and Survival Meta-Analysis

PURPOSE/OBJECTIVE(S)

Tumor Treating Fields (TTFields) are electric fields that exert forces on cancer cells, disrupting processes critical for cancer cell viability and tumor progression. TTFields therapy is FDA-approved for patients with newly diagnosed glioblastoma (GBM) on the basis of the randomized controlled EF-14 study (NCT00916409). Subsequent approvals and increased worldwide adoption of TTFields has led to the question of whether or not a consistent survival benefit has been observed in the real-world setting, and whether device usage has played a role.

MATERIALS/METHODS

PubMed, Embase, and the Cochrane Library were searched using pre-defined terms, to identify clinical studies (including comparative and single-cohort studies) evaluating overall survival (OS) in adult patients with GBM treated with TTFields therapy added to radiochemotherapy. The Cochran Q test was used to assess inter-study heterogeneity, and results were quantified using the Higgins I2 statistic. Data were pooled, and a survival curve created using a distribution-free random-effects method.

RESULTS

Records identified from the literature search were screened and distilled using pre-specified methods, down to 8 studies evaluating the clinical efficacy of TTFields therapy in newly diagnosed GBM (spanning diverse geographic regions). Six studies (reporting on a total of 1378 patients) compared the addition of TTFields therapy to standard of care (SOC) vs SOC alone, and were included in a pooled analysis for OS. Meta-analysis of data from the 6 studies indicated a significant OS benefit for patients receiving TTFields therapy vs those who did not (hazard ratio [HR]: 0.62; 95% CI, 0.52-0.73; P < 0.001). Sensitivity analysis confirmed the pooled effect was robust and not dependent on any individual study. Of the 6 included in the analysis, 5 were post-approval for which the pooled median OS was 22.2 months (95% CI, 17.3-42.6) vs 17.3 months (95% CI, 13.6-22.0) for the TTFields/SOC group and the SOC group, respectively. Rates of gross total resection were numerically higher in the real-world setting, irrespective of TTFields use. Among studies reporting data on TTFields device usage, an average device usage rate of 75% or higher was found to consistently correlate with prolonged OS when compared to an average usage rate < 75% (pooled HR: 0.63; 95% CI, 0.48-0.83; P = 0.001).

CONCLUSION

Meta-analysis of comparative studies suggests a significant OS benefit when TTFields therapy is added to standard radiochemotherapy for patients with newly diagnosed GBM, and that a ≥ 75% usage rate may translate to clinical benefit in the real-world setting.

Patient-Specific Segmentation-Based Treatment Planning vs. NovoTAL for TTFields Therapy in Glioblastoma

PURPOSE/OBJECTIVE(S)

Patients treated with Tumor Treating Fields (TTFields) therapy for glioblastoma (GBM) have array layouts planned by NovoTAL. NovoTAL requires morphometric inputs and maximizes field intensity at the tumor. Patient-specific segmentation-based treatment planning (SBTP) software uses segmentation-based plans to maximize power density at defined regions of interest (ROIs). This technical analysis compared expected local minimum power density (LMiPD; mW/cm3) and local minimum field intensity (LMiFI; V/cm) delivered to ROIs with array layouts planned with SBTP vs NovoTAL. We hypothesized that SBTP has the potential to increase LMiPD and LMiFI to ROIs vs NovoTal.

MATERIALS/METHODS

37 patients from 5 sites who received TTFields therapy for GBM using NovoTAL were included. Treatment plans using the prescribed/treated NovoTAL layouts were created with SBTP. De novo SBTP layouts were also created. Three ROIs representing the original treated GBM (CTV), high risk margin around the GBM (CTV-2), and recurrent GBM (CTV-R) were created. Plans were optimized to CTV. SBTP vs NovoTAL LMiPD and LMiFI volumetrics to ROIs were evaluated. LMiPD and LMiFI were normalized with the delivered current from the treated NovoTAL layout. Layout rankings based on LMiPD and LMiFI, average LMiPD and LMiFI, D95, D5, DVHs, and voxel-by-voxel LMiPD and LMiFI for SBTP derived from NovoTAL layouts were compared to de novo SBTP layouts (paired t-tests).

RESULTS

Average LMiPD (1.551 vs 1.194) and LMiFI (1.115 vs 0.978) to CTV were significantly higher with SBTP vs NovoTAL (P < 0.0001 for each). Average LMiPD (1.445 vs 1.164) and LMiFI (1.197 vs 1.077) to CTV-2 were also higher (P < 0.0001 for each). There was a positive trend to higher average LMiPD (1.203 vs 1.157; P = 0.212) and LMiFI (1.103 vs 1.090; P = 0.311) to CTV-R. Top ranked overall layouts by LMiPD to CTV were SBTP layouts (97%; n = 36). Percent ratio ([SBTP-NovoTAL]/NovoTAL*100) D95 for LMiPD was 34% (to CTV), 24% (to CTV-2), and 5% (to CTV-R) and for LMiFI was 16%, 12%, and 2% respectively. Percent ratio D5 for LMiPD was 31%, 24%, and 3% and for LMiFI was 14%, 9%, and 0%, respectively. For a given percent CTV volume, minimum LMiPD and LMiFI were higher with SBTP (95%, n = 35; DVH curves shifted to right). SBTP yielded higher LMiPD and LMiFI to the majority of voxels within the CTV (95%, n = 35). With SBTP, LMiPD to CTV was significantly higher than to CTV-R (P < 0.001).

CONCLUSION

Overall, these data demonstrate that SBTP compared to NovoTAL yielded higher expected average LMiPD and LMiFI, D95, D5, and percent voxel LMiPD and LMiFI to defined ROIs. Higher LMiPD and LMiFI delivered to CTV vs CTV-R with SBTP suggests a benefit to re-planning if the GBM recurs. Given previous reports showing that higher LMiPD and LMiFI are positively correlated with improved overall and progression free survival, patient-specific SBTP may lead to improved clinical outcomes for GBM patients vs NovoTAL.

Association of Tumor Treating Fields (TTFields) therapy with survival in newly diagnosed glioblastoma: a systematic review and meta-analysis

PURPOSE

Tumor Treating Fields (TTFields) therapy, an electric field-based cancer treatment, became FDA-approved for patients with newly diagnosed glioblastoma (GBM) in 2015 based on the randomized controlled EF-14 study. Subsequent approvals worldwide and increased adoption over time have raised the question of whether a consistent survival benefit has been observed in the real-world setting, and whether device usage has played a role.

METHODS

We conducted a literature search to identify clinical studies evaluating overall survival (OS) in TTFields-treated patients. Comparative and single-cohort studies were analyzed. Survival curves were pooled using a distribution-free random-effects method.

RESULTS

Among nine studies, seven (N = 1430 patients) compared the addition of TTFields therapy to standard of care (SOC) chemoradiotherapy versus SOC alone and were included in a pooled analysis for OS. Meta-analysis of comparative studies indicated a significant improvement in OS for patients receiving TTFields and SOC versus SOC alone (HR: 0.63; 95% CI 0.53-0.75; p < 0.001). Among real-world post-approval studies, the pooled median OS was 22.6 months (95% CI 17.6-41.2) for TTFields-treated patients, and 17.4 months (95% CI 14.4-21.6) for those not receiving TTFields. Rates of gross total resection were generally higher in the real-world setting, irrespective of TTFields use. Furthermore, for patients included in studies reporting data on device usage (N = 1015), an average usage rate of ≥ 75% was consistently associated with prolonged survival (p < 0.001).

CONCLUSIONS

Meta-analysis of comparative TTFields studies suggests survival may be improved with the addition of TTFields to SOC for patients with newly diagnosed GBM.

Multi-Institutional Patterns of Use of Tumor-Treating Fields for Patients with Malignant Pleural Mesothelioma

(1) Background: The objective of this analysis was to evaluate the device usage rates and patterns of use regarding Tumor-Treating Fields (TTFields) for patients with malignant pleural mesothelioma (MPM) throughout the US. (2) Methods: We evaluated de-identified data from 33 patients with MPM enrolled in FDA-required HDE protocols at 14 institutions across the US from September 2019 to March 2022. (3) Results: The median number of total TTFields usage days was 72 (range: 6-649 days), and the total treatment duration was 160 months for all patients. A low usage rate (defined as less than 6 h per day, 25%) was observed in 34 (21.2%) months. The median TTFields usage in the first 3 months was 12 h per day (range: 1.9-21.6 h), representing 50% (range: 8-90%) of the potential daily duration. The median TTFields usage after 3 months decreased to 9.1 h per day (range: 3.1-17 h), representing 38% (range: 13-71%) of the daily duration, and was lower than usage in the first 3 months (p = 0.01). (4) Conclusions: This study represents the first multicenter analysis of real-world TTFields usage based on usage patterns for MPM patients in clinical practice. The real-world usage level was lower than the suggested daily usage. Further initiatives and guidelines should be developed to evaluate the impact of this finding on tumor control.

Feasibility and Safety of Diffusing Alpha-Emitter Radiation Therapy for Recurrent or Unresectable Skin Cancers

Importance

Patients with recurrent or unresectable skin cancers have limited treatment options. Diffusing alpha-emitter radiation therapy (DaRT), a novel solid tumor management strategy using alpha-particle interstitial brachytherapy, may address this challenge.

Objective

To evaluate the feasibility and safety of using DaRT to manage recurrent or unresectable skin cancers.

Design, Setting, and Participants

This prospective cohort study of patients who received a 2-week to 3-week treatment course and were followed up for 24 weeks after treatment during 2021 and 2022 at 2 sites in the US. Patients with malignant skin tumors or soft tissue tumors were recruited if they had limited treatment options for tumors recurrent after prior surgery or external beam radiotherapy or unresectable tumors.

Intervention

Patients underwent DaRT to deliver a physical dose of 10 Gy (equivalent weighted dose of 200 CGE) to the tumor.

Main Outcomes and Measures

Feasibility of the DaRT procedure was evaluated based on the ability of investigators to successfully deliver radiation to the tumor. Patients were followed up for adverse events (AEs) for 24 weeks and for tumor response by physicians' physical examination and imaging 12 weeks after device removal.

Results

This study included 10 participants with recurrent or unresectable skin cancer (median [IQR] age, 72 [68-75] years; 6 males [60%]; 4 females [40%]). Six patients (60%) had recurrent disease, and 4 (40%) had tumors that were deemed unresectable. Tumors were located on the nose, chin, eyelid, scalp, neck, trunk, and extremities. Median (range) tumor volume before treatment was 2.1 cm3 (0.65-12.65 cm3). The mean (SD) prescription dose coverage of the gross tumor volume was 91% (2.8%) with all tumors having coverage of 85% or more. No device-related grade 3 AEs were noted. Common AEs were grade 1 to 2 erythema, edema, and pruritus. At 12 weeks following treatment, there was a 100% complete response rate. Nine of 10 complete responses (90%) were confirmed by CT imaging.

Conclusions and Relevance

This cohort study suggests the feasibility and preliminary safety of DaRT in the management of recurrent or unresectable skin cancers. The favorable safety profile and high response rates are promising. A US trial for marketing approval based on this pilot study is under way.

Trial Registration

ClinicalTrials.gov Identifier: NCT04377360.

Predicting future cancer incidence by age, race, ethnicity, and sex

INTRODUCTION

Cancer remains a substantial burden on society. Our objective was to update projections on the number of new cancer diagnoses in the United States by age, race, ethnicity, and sex through 2040.

MATERIALS AND METHODS

Population-based cancer incidence data were obtained using Surveillance, Epidemiology, and End Results (SEER) data. Population estimates were made using the 2010 US Census data population projections to calculate future cancer incidence. Trends in age-adjusted incidence rates for 23 cancer types along with total cancers were calculated and incorporated into a second projection model.

RESULTS

If cancer incidence remains stable, annual cancer diagnoses are projected to increase by 29.5% from 1.86 million to 2.4 million between 2020 and 2040. This increase outpaces the projected US population growth of 12.3% over the same period. The population of older adults is projected to represent an increasing proportion of total cancer diagnoses with patients ≥65 years old comprising 69% of all new cancer diagnoses and patients ≥85 years old representing 13% of new diagnoses by 2040. Cancer diagnoses are projected to increase in racial minority groups, with a projected 44% increase in Black Americans (from 222,000 to 320,000 annually), and 86% in Hispanic Americans (from 175,000 to 326,000 annually).

DISCUSSION

The landscape of cancer care will continue to change over the next several decades. The burden of disease will remain substantial, and the growing proportion of older and minority patients with cancer remains of particular interest. These projections should help guide future health policy and research priorities.

Determinants of Tumor Treating Field Usage in Patients with Primary Glioblastoma: A Single Institutional Experience

Background

Determinates of tumor treating fields (TTFields) usage in patients receiving combined modality therapy for primary IDH wild-type glioblastoma are currently unknown.

Methods

Ninety-one patients underwent maximal debulking surgical resection, completed external beam radiotherapy with concurrent Temozolomide (TMZ), and initiated adjuvant TMZ with or without TTFields. We performed a retrospective analysis of patient, tumor, and treatment related factors that affected TTFields usage.

Results

We identified three TTFields usage subgroups: 32 patients that declined TTFields, 40 patients that started, but had a monthly compliance less than 75% or used it for less than 2 months, and 19 patients who used TTFields for 2 or more months and maintained an average monthly compliance greater than 75%. With 26.5 months median follow up for surviving patients, the 1 and 3-year actuarial overall survival for all patients was 80% and 18%, respectively. On multivariate analysis TTFields use (p=0.03), extent of surgical resection (p=0.02), and MGMT methylation status (p=0.01) were significantly associated with overall survival. TTFields usage was explored as a continuous variable and higher average usage was associated with longer overall survival (p=0.03). There was no relationship between patient, tumor, or treatment related factors and a patient’s decision to use TTFields.

Conclusions

No subgroup of patients was more or less likely to initiate TTFields therapy and no subgroup was more or less likely to use TTFields as prescribed. The degree of TTFields compliance may be associated with improved survival independent of other factors.

The Impact of Tumor Treating Fields on Glioblastoma Progression Patterns

BACKGROUND

Tumor-treating fields (TTFields) is an antimitotic treatment modality that interferes with glioblastoma cell division and organelle assembly by delivering low-intensity alternating electric fields to the tumor. A previous analysis from the pivotal EF-14 trial demonstrated a clear correlation between TTFields dose-density at the tumor bed and survival in patients treated with TTFields. This study tests the hypothesis that the antimitotic effects of TTFields result in measurable changes in the location and patterns of progression of newly diagnosed glioblastoma (nGBM) patients.

METHODS

MRI images of 428 nGBM patients that participated in the pivotal EF-14 trial were reviewed and the rates at which distant progression occurred in the TTFields treatment and control arm were compared. Realistic head models of 252 TTFields treated patients were created and TTFields intensity distributions were calculated using a Finite Elements Method. TTFields dose was calculated within regions of the tumor bed and normal brain and its relationship with progression determined.

RESULTS

Distant progression was frequently observed in the TTFields-treated arm, and distant lesions in the TTFields-treated arm appeared at larger distances from the primary lesion than in the control arm. Distant progression correlated with improved clinical outcome in the TTFields patients, with no such correlation observed in the controls. Areas of normal brain that remained normal were exposed to higher TTFields doses compared to normal brain that subsequently exhibited neoplastic progression. Additionally, the average dose to areas of enhancing tumor that returned to normal was significantly higher than in the areas of normal brain that progressed to enhancing tumor.

CONCLUSIONS

There was a direct correlation between TTFields dose distribution and tumor response, confirming the therapeutic activity of TTFields and the rationale for optimizing array placement to maximize TTFields dose in areas at highest risk of progression, as well as array layout adaptation after progression.

Comparison of Chemotherapy vs Chemotherapy Plus Total Hysterectomy for Women With Uterine Cancer With Distant Organ Metastasis

This cohort study evaluates the overall survival for patients with uterine cancer with distant organ metastasis treated with chemotherapy alone vs chemotherapy plus total abdominal hysterectomy.

The role of radiation therapy in the management of cutaneous malignancies. Part II: When is radiation therapy indicated?

Radiation therapy may be performed for a variety of cutaneous malignancies, depending on patient health status, tumor clinical and histologic features, patient preference, and resource availability. Dermatologists should be able to recognize the clinical scenarios in which radiation therapy is appropriate, as this may reduce morbidity, decrease risk of disease recurrence, and improve quality of life. The second article in this 2-part continuing medical education series focuses on the most common indications for radiation therapy in the treatment of basal cell carcinoma, cutaneous squamous cell carcinoma, dermatofibrosarcoma protuberans, Merkel cell carcinoma, Kaposi sarcoma, angiosarcoma, cutaneous lymphoma, melanoma, undifferentiated pleomorphic sarcoma, and sebaceous carcinoma.

The role of radiation therapy in the management of cutaneous malignancies. Part I: Diagnostic modalities and applications

Radiation therapy offers distinct advantages over other currently available treatments for cutaneous malignancies in certain circumstances. Dermatologists and dermatologic surgeons should be familiar with the available radiation therapy techniques as well as their value and potential limitations in a variety of clinical scenarios. The first article in this 2-part continuing medical education series highlights the mechanisms, modalities, and applications of the most commonly used radiotherapy treatments as they relate to cutaneous oncology. We review the current indications for the use of radiation in the treatment of various cutaneous malignancies, the techniques commonly employed in modern radiotherapy, and the associated complications.

Prevention and Management of Dermatologic Adverse Events Associated With Tumor Treating Fields in Patients With Glioblastoma

Importance: Tumor Treating Fields (TTFields) are an anti-mitotic treatment approved for treating newly diagnosed and recurrent glioblastoma, and mesothelioma. TTFields in glioblastoma comprise alternating electric fields (200 kHz) delivered continuously, ideally for ≥18 h/day, to the tumor bed via transducer arrays placed on the shaved scalp. When applied locoregionally to the tumor bed and combined with systemic temozolomide chemotherapy, TTFields improved overall survival vs. temozolomide alone in patients with newly diagnosed glioblastoma. Improved efficacy outcomes with TTFields were demonstrated, while maintaining a well-tolerated and manageable safety profile. The most commonly-reported TTFields–associated adverse events (AEs) are beneath-array dermatologic events. Since survival benefit from TTFields increases with duration-of-use, prevention and management of skin AEs are critical to maximize adherence. This paper describes TTFields-associated dermatological AEs and recommends prevention and management strategies based on clinical trial evidence and real-world clinical experience.

Observations: TTFields–associated skin reactions include contact dermatitis (irritant/allergic), hyperhidrosis, xerosis or pruritus, and more rarely, skin erosions/ulcers and infections. Skin AEs may be prevented through skin-care and shifting (~2 cm) of array position during changes. TTFields–related skin AE management should be based on clinical phenotype and severity. Depending on diagnosis, recommended treatments include antibiotics, skin barrier films, moisturizers, topical corticosteroids, and antiperspirants. Water-based lotions, soaps, foams, and solutions with minimal impact on electrical impedance are preferred with TTFields use over petroleum-based ointments, which increase impedance.

Conclusions: Early identification, prophylactic measures, and symptomatic skin AE management help patients maximize TTFields usage, while maintaining quality-of-life and optimizing therapeutic benefit.

Implications for practice: TTFields confer a survival benefit in patients with glioblastoma that correlates positively with duration of daily use. Skin events (rash) are the primary treatment-related AE that can limit duration of use. The recommendations described here will help healthcare professionals to recognize, prevent, and manage dermatologic AEs associated with TTFields treatment. These recommendations may improve cutaneous health and support adherence to therapy, both of which would maximize treatment outcomes.

P14.66 TTFields dose distribution and tumor growth patterns confirm clinical activity of TTFields: MRI analysis of the randomized phase 3 EF-14 trial

BACKGROUND

The randomized phase 3 EF-14 trial showed that the addition of tumor treating fields (TTFields) to temozolomide (TMZ) treatment improved survival in newly diagnosed glioblastoma patients over TMZ alone. As TTFields delivery is designed to optimize dose at the tumor bed, we hypothesized that tumor recurrence is likely to occur in distant sites and we investigated the pattern of tumor growth at relapse in due consideration of TTFields dose intensity distribution.

METHODS

Patients on therapy for more than 2 months who exhibited radiological progression were included in the study (treatment: N=280/466, control: N=122/229) Contrast-enhanced T1-weighted scans at baseline and at relapse served for segmentation of enhancing tumor and necrosis. Lesions outside a proximal boundary zone of 20mm surrounding lesions identified at baseline were defined as distal. In addition, infratentorial progression was assessed. Moreover, we identified patients treated with TTFields with sufficient MRI data for dose calculations and radiographically confirmed tumor relapse (N=225/466). TTFields intensity distributions were computed in a finite element method applied in a realistic head model with virtual transducer arrays. TTFields dose density (mW/cm3) was defined as TTFields power loss density multiplied by average patient compliance during the first 6 months of therapy. At baseline, regions of residual tumor and regions of normal brain were identified to calculate TTFields dose within each of these regions and noted its relationship with subsequent recurrence.

RESULTS

Distal progressions were more common in the TTFields arm (18% vs. 8%). Infratentorial progression was seen in 4% of the treatment arm vs. 0 patients in the control. Lesions at progression were more distant from the original lesion in the TTFields arm (57.0 + 26.2 mm vs. 46.6 + 14.8 mm). Local tumors grew at a significantly lower pace in the TTFields arm as compared to the control arm (3.6 + 14.5 ml vs. 8.3 + 17.9 ml). The average dose density in areas of enhancing tumor that regressed to normal was higher than in the areas of normal brain that progressed to enhancing tumor (0.84 mW/cm3 vs. 0.75 mW/cm3). Regardless of the expansion margin used for analysis, TTFields dose density in areas of normal brain that remained normal at the time of progression was higher than in the areas that progressed to enhancing tumor.

CONCLUSIONS

TTFields appear to induce distant tumor growth pattern and are associated with a lower tumor growth rate. In addition, the importance of dose density at the tumor bed is stressed as higher dose densities were seen in areas of normal brain that remain normal at the time of progression providing further rationale for carefully planning array placement to maximize delivery to areas at higher risk of recurrence. Taken together, these findings confirm the clinical activity of TTFields.

Integration of Tumor-Treating Fields into the Multidisciplinary Management of Patients with Solid Malignancies

Tumor treating fields, a noninvasive cancer treatment using low intensity alternating electric fields, offers clinical opportunities with unique challenges. This review focuses on the mechanism of action of this treatment, the known pre‐clinical and clinical experience, and the practical issues surrounding its use in the multidisciplinary management of patients with solid malignancies.

Tumor‐treating fields (TTFields) are a noninvasive antimitotic cancer treatment consisting of low‐intensity alternating electric fields delivered to the tumor or tumor bed via externally applied transducer arrays. In multiple in vitro and in vivo cancer cell lines, TTFields therapy inhibits cell proliferation, disrupts cell division, interferes with cell migration and invasion, and reduces DNA repair. Human trials in patients with primary glioblastoma showed an improvement in overall survival, and trials in patients with unresectable malignant pleural mesothelioma showed favorable outcomes compared with historical control. This led to U.S. Food and Drug Administration approval in both clinical situations, paving the way for development of trials investigating TTFields in other malignancies. Although these trials are ongoing, the existing evidence suggests that TTFields have activity outside of neuro‐oncology, and further study into the mechanism of action and clinical activity is required. In addition, because TTFields are a previously unrecognized antimitotic therapy with a unique mode of delivery, the oncological community must address obstacles to widespread patient and provider acceptance. TTFields will likely join surgery, systemic therapy, and radiation therapy as a component of multimodality management of patients with solid malignancies.

Implications for Practice.

Tumor‐treating fields (TTFields) exhibit a broad range of antitumor activities. Clinically, they improve overall survival for patients with newly diagnosed glioblastoma. The emergence of TTFields has changed the treatment regimen for glioblastoma. Clinicians need to understand the practical issues surrounding its use in the multidisciplinary management of patients with glioblastoma. With ongoing clinical trials, TTFields likely will become another treatment modality for solid malignancies.

Abstract CT204: Increasing Tumor Treating Fields dose at the tumor bed improves survival: Setting a framework for TTFields dosimetry based on analysis of the EF-14 Phase III trial in newly diagnosed glioblastoma

Introduction: Tumor Treating Fields (TTFields) are low intensity, intermediate frequency, anti-mitotic alternating electric fields that are delivered via transducer arrays placed on the shaved scalp. TTFields are approved for Glioblastoma (GBM) based on improved overall survival (OS) and progression free survival (PFS) in the Phase III EF-14 [NCT00916409] trial in newly diagnosed GBM patients. To test the hypothesis if increasing TTFields dose at the tumor bed improves patient outcomes, we performed a simulation-based study investigating the association between TTFields dose and overall survival (OS) and progression free survival (PFS) in EF-14 TTFields-treated patients.

Methods: EF-14 patients cases (N=340) were included. Realistic computational head models of the patients were derived from T1-contrast images captured at baseline. Patients who were on treatment for less than two months, or for whom MRI image quality was insufficient for the creation of a realistic head model were excluded from the analysis (N=126). The transducer array layout on each patient was obtained from EF-14 records; average compliance (fraction of time patient was on active treatment), and average electrical current delivered to the patient were derived from log files of the TTFields devices used by patients. TTFields intensity distributions and power loss densities were calculated for each patient using a Finite Elements Method. Local Minimum Dose Density (LMiDD) was defined as the product of TTFields power loss density and the average patient compliance. The average LMiDD within a tumor bed comprising the Gross Tumor Volume and the Peritumoral Boundary Zone 3 mm wide was calculated.

Results: The median OS and PFS were significantly longer when average LMiDD in the tumor bed was &gt;0.77 MmW/cm3: OS (25.2 vs. 20.4 months, p=0.003, HR=0.611) and PFS (8.5 vs 6.7 months, p=0.02, HR=0.699). The median OS and PFS were longer when average TTFields intensity was &gt;1.06 V/cm OS (24.3 vs. 21.6 months, p=0.03, HR=0.705) and PFS (8.1 vs 7.9 months, p=0.03, HR=0.721).

Conclusions: In this study we present the first reported analysis demonstrating patient-level dose responses to TTFields. Increasing Tumor Treating Fields dose at the tumor bed improves survival (OS and PFS) in newly diagnosed GBM. We provide a rigorous definition for TTFields dose, and set a conceptual framework for future work on TTFields dosimetry and treatment planning.

Citation Format: Matthew T. Ballo, Noa Urman, Ze'ev Bomzon, Gitit Lavy-Shahaf, Steven Toms. Increasing Tumor Treating Fields dose at the tumor bed improves survival: Setting a framework for TTFields dosimetry based on analysis of the EF-14 Phase III trial in newly diagnosed glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT204.

Predicting future cancer incidence by age and gender

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Background: Cancer remains a substantial and unique burden on society. While the impact of changing demographics on cancer incidence has previously been characterized (Smith et al, JCO, 2009), this has not been done with updated population data. Our objective was to update projections on the number of new cancer diagnoses in the United States by age and gender through 2040. Methods: Population-based cancer incidence data were obtained using SEER 18 delay-adjusted data. Population estimates were made by age, race, and gender using the 2010 US Census data population projections to calculate future cancer incidence rates. Trends in age- adjusted incidence rates for 23 cancer types were calculated as previously described (Edwards et al, Cancer, 2014). Results: From 2020 to 2040 the projected total cancer incidence will increase by almost 30% from 1.86 million to 2.4 million. This increase is due to the projected increase in population growth, particularly in older individuals. The population of older adults will represent a growing proportion of total cancer diagnoses. Specifically, patients ≥65 years old will make up 69% of all new cancer diagnoses, while 13% of new diagnoses will be in patients ≥85 years old by 2040 (see Table). Cancer diagnoses in females are projected to rise 27%, while male cancer diagnoses are projected to increase by 32% from 2020 to 2040. The incidence rates for lung, colorectal, and prostate cancer are expected to decline, while those for thyroid, liver, melanoma and myeloma are expected to increase. Conclusions: The landscape of cancer care will continue to change over the next several decades. The burden of disease will remain substantial and will continue to disproportionately affect older adults. The growing proportion of older cancer patients and changes in site-specific cancer incidence rates remain of particular interest. These projections should help guide future health policy and research priorities. [Table: see text]

Association of total hysterectomy with survival among newly diagnosed uterine cancer patients with distant organ metastasis

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Background: There is growing evidence that definitive local therapies (surgery or radiotherapy) may increase patient’s survival for some types of metastatic cancers. However, the role of total abdominal hysterectomy (TAH) for newly diagnosed uterine cancer with distant organ metastasis has not been established. The objective of this study is to determine the potential overall survival (OS) benefit associated with TAH for distant metastatic uterine cancer. Methods: The National Cancer Database was analyzed to evaluate OS for newly diagnosed uterine cancer patients with metastasis to brain, lung, liver, bone or distant lymph node, treated with chemotherapy with or without TAH. Those without treatment, treated with definitive pelvic radiotherapy, or without baseline variables were excluded. OS was analyzed using the Kaplan-Meier method, log-rank test, Cox proportional hazards models, and propensity score-matched analyses. In order to control the selection biases, we performed Landmark analysis, and survival analysis by the sequence of chemotherapy and TAH. Separate survival analysis was performed for patients who received chemotherapy plus definitive pelvic radiotherapy (RT) or chemotherapy plus TAH and definitive pelvic RT. Results: From 2010 to 2014, 1,809 uterine cancer patients with distant organ metastasis received chemotherapy alone and 1,388 patients received chemotherapy plus TAH. At a median follow-up of 13.4 months, addition of TAH to chemotherapy was associated with improved survival on univariate (HR 0.57; P < 0.001) and multivariate analysis (HR 0.59; P < 0.001) compared to chemotherapy alone. Propensity score-matched analysis demonstrated superior median survival (19.8 vs 11.0 months) and 2-year OS (44% vs 28%) with TAH (multivariate HR 0.59; P < 0.001). Landmark analyses limited to long-term survivors of ≥0.5, ≥1, and ≥2 years showed improved OS with TAH in all subsets (all P < 0.05). The benefit of TAH was present among not only those involving one metastatic site (HR 0.59; P < 0.001), but also those involving multiple metastatic sites (HR 0.60; P < 0.001). Separate survival analyses showed chemotherapy plus definitive pelvic RT or chemotherapy plus TAH and RT were both superior to chemotherapy alone. Conclusions: In this large contemporary analysis, uterine cancer patients with distant organ metastasis receiving TAH and chemotherapy had substantial longer survival than patients treated with chemotherapy alone. Prospective trials evaluating TAH for metastatic uterine cancer are warranted.

The association of age with acute toxicities in NRG oncology combined modality lower GI cancer trials

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Background: This study sought to compare adverse events (AEs) of older and younger adults with lower gastrointestinal (GI) malignancies treated on NRG studies. Methods: Data from six NRG trials (RTOG 9811/0012/0247/0529/0822 & NSABP R-04), testing combined modality therapy (radiation and chemotherapy) in patients with anal or rectal cancer, were collected to test the hypothesis that older age was associated with increase in acute ( ≤ 90 days from treatment start) AEs. AEs were defined as GI, Genitourinary (GU), hematologic, or skin. AEs and compliance with protocol-directed therapy were compared between patients aged ≥ 70 years and < 70 years. Categorical variables were compared across age groups using the chi-square test. The association of age on AEs was evaluated using a covariate-adjusted logistic regression model, with odds ratio (OR) reported. To adjust for multiple comparisons, a p-value < 0.01 was considered statistically significant. Results: Data from 2525 patients were collected (43% female, 72% rectal cancer). There were 380 patients ≥ 70 years old (15%). Older patients were more likely to have worse baseline performance status (PS 1 or 2) (23% vs. 16%, p <0.01), but otherwise baseline characteristics were similar. Older patients were less likely to have completed their chemotherapy (78% vs. 87%, p < 0.01), but had similar median RT duration. On univariate analysis, patients ≥ 70 were more likely to experience grade ≥ 3 GI AEs (36% vs. 23%, OR 1.82, p < 0.001), and less likely to experience ≥ 3 skin AEs (8% vs. 14%, OR 0.56, p = 0.002). There was no difference between GU or hematologic AEs. On multivariable analysis, age ≥ 70 was associated with grade ≥ 3 GI AE (OR 1.80, 95% CI: 1.40, 2.31; p < 0.001) after adjusting for gender, PS, T stage, disease site, RT duration, and chemotherapy completion. Conclusions: Older patients with curable lower GI cancers who underwent combined-modality therapy were less likely to complete chemotherapy and were more likely to experience serious GI toxicity, whereas younger patients had higher rates of serious skin AEs.

Definitive Pelvic Radiotherapy and Survival of Patients With Newly Diagnosed Metastatic Anal Cancer

Background: Chemotherapy with or without pelvic radiotherapy (RT) is included in the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for metastatic anal cancer (MAC), despite limited clinical evidence for RT in this setting. In addition, increasing evidence shows that local therapies, including RT, may increase patient survival for some types of metastatic cancers. The purpose of this study was to evaluate the patterns of care and association between definitive pelvic RT and overall survival (OS) for patients with MAC. Methods: The National Cancer Database was analyzed to evaluate OS of patients with newly diagnosed MAC treated with chemotherapy with or without pelvic RT. Those who did not undergo treatment, treated with surgery, or without baseline variables were excluded. OS was analyzed using the Kaplan-Meier method, log-rank test, Cox proportional hazards models, and propensity score-matched analyses. Results: From 2004 through 2015, 437 patients received chemotherapy alone and 1,020 received pelvic chemoradiotherapy (CRT). At a median follow-up of 17.3 months, CRT was associated with improved OS on univariate (P<.001) and multivariate analysis (hazard ratio [HR], 0.70; 95% CI, 0.61-0.81; P<.001). Propensity score-matched analysis demonstrated superior median survival (21.3 vs 15.9 months) and 2-year OS rates (46% vs 34%) with CRT compared with chemotherapy alone (P<.001). Landmark analyses limited to long-term survivors of ≥1, ≥2, and ≥4 years showed improved OS with CRT in all subsets (all P<.05). CRT with therapeutic doses (≥45 Gy) was associated with longer median survival than palliative doses (<45 Gy) and chemotherapy alone (24.9 vs 10.9 vs 15.6 months, respectively; P<.001). The benefit of CRT was present among not only those with distant lymph node metastasis (HR, 0.63; P=.04) but also those with distant organ disease (HR, 0.74; P<.001). Conclusions: In this large hypothesis-generating analysis, patients with newly diagnosed MAC who received definitive pelvic RT with chemotherapy lived significantly longer than those who received chemotherapy alone. Prospective trials evaluating definitive local RT for MAC are warranted.

Iodine-125 Episcleral Plaque Brachytherapy for AJCC T4 Posterior Uveal Melanoma: Clinical Outcomes in 158 Patients

Background/Aims

The aim of this study is to report the burden of ocular morbidity following iodine-125 episcleral plaque brachytherapy (EPBT) in the treatment of American Joint Committee on Cancer (AJCC) T4-staged posterior uveal melanoma (PUM).

Methods

Clinical records of patients with T4-staged PUM treated with ¹²⁵I EPBT were analyzed for incidence of treatment failure and radiation-induced complications.

Results

Cumulative incidence of local treatment failure was 9% (95% CI 5-15%) at 5 years and was associated with decreased tumor height (HR = 0.78; p = 0.01). Cumulative incidence of enucleation at 5 years was 21% and was correlated with worsening baseline visual acuity (HR = 1.42; p = 0.05). Increasing patient age was associated with higher rates of vitreous hemorrhage (HR = 1.03; p = 0.02) and cataract surgery (HR = 1.05; p < 0.001). Increased tumor height was associated with higher rates of neovascular glaucoma (HR = 1.16; p = 0.03) and vitreous hemorrhage (HR = 1.23; p < 0.001).

Conclusion

¹²⁵I EPBT is an effective treatment for T4-staged PUM and achieves high rates of local control. Treatment failure appears to be more common among minimally elevated tumors. Other causes of ocular morbidity were associated with increasing tumor height, patient age, and baseline visual acuity.

Clinical pathway creation and adherence at a large hybrid cancer center

298

Background: Clinical pathways are valuable in reducing treatment variation, improving outcomes, and reducing costs in an oncology setting. With input of clinical stakeholders at West Cancer Center, we created and implemented a melanoma clinical pathway to improve care and facilitate standardization between melanoma sub-specialists and general oncologists. Retrospective pathway adherence was assessed to inform quality improvement goals. Methods: Using national guidelines and expert literature review, we developed a pathway defining a center-wide algorithmic approach to treat melanoma. Prior adherence to the pathway was retrospectively assessed by evaluating treatment during 1 year across 8 metrics. All patients who received systemic melanoma therapy during the study period at a large cancer center ( > 5000 new patients annually) were included in the assessment. Of the included patients, metric adherence was only measured when applicable. Adherence rates were described for predefined melanoma subspecialists versus predefined general oncologists without a declared subspecialty in melanoma. Significance was assessed with fisher exact test. Results: The following metrics were defined by the expert team as essential components of melanoma pathway; receipt of wide local excision; receipt of sentinel lymph node biopsy; presentation at multidisciplinary conference; molecular profiling before treatment of metastatic disease; treatment with preferred regimens in 1st line, 2nd line, and 3rd line; and clinical trial participation. Ninety patients were evaluated. Conclusions: Most differences in pathway adherence were found to be not significant. Clinical trial accrual was higher among melanoma subspecialists compared to general oncologists. Clinical pathways allow patients treated by general oncologists to benefit from the expertise of subspecialists and improve quality of care.[Table: see text]

Prospective Comparison of Toxicity and Cosmetic Outcome After Accelerated Partial Breast Irradiation With Conformal External Beam Radiotherapy or Single-Entry Multilumen Intracavitary Brachytherapy

PURPOSE

This study aimed to prospectively characterize toxicity and cosmesis after accelerated partial breast irradiation (APBI) with 3-dimensional conformal radiation therapy (CRT) or single-entry, multilumen, intracavitary brachytherapy.

METHODS AND MATERIALS

A total of 281 patients with pTis, pT1N0, or pT2N0 (≤3.0 cm) breast cancer treated with segmental mastectomy were prospectively enrolled from December 2008 through August 2014. APBI was delivered using 3-dimensional CRT (n = 29) or with SAVI (n = 176), Contura (n = 56), or MammoSite (n = 20) brachytherapy catheters. Patients were evaluated at protocol-specified intervals, at which time the radiation oncologist scored cosmetic outcome, toxicities, and recurrence status using a standardized template.

RESULTS

The median follow-up time is 41 months. Grade 1 seroma and fibrosis were more common with brachytherapy than with 3-dimensional CRT (50.4% vs 3.4% for seroma; P < .0001 and 66.3% vs 44.8% for fibrosis; P = .02), but grade 1 edema was more common with 3-dimensional CRT than with brachytherapy (17.2% vs 5.6%; P = .04). Grade 2 to 3 pain was more common with 3-dimensional CRT (17.2% vs 5.2%; P = .03). Actuarial 5-year rates of fair or poor radiation oncologist-reported cosmetic outcome were 9% for 3-dimensional CRT and 24% for brachytherapy (P = .13). Brachytherapy was significantly associated with inferior cosmesis on mixed model analysis (P = .003). Significant predictors of reduced risk of adverse cosmetic outcome after brachytherapy were D0.1cc (skin) ≤102%, minimum skin distance >5.1 mm, dose homogeneity index >0.54, and volume of nonconformance ≤0.89 cc. The 5-year ipsilateral breast recurrence was 4.3% for brachytherapy and 4.2% for 3-dimensional CRT APBI patients (P = .95).

CONCLUSIONS

Brachytherapy APBI is associated with higher rates of grade 1 fibrosis and seroma than 3-dimensional CRT but lower rates of grade 1 edema and grade 2 to 3 pain than 3-dimensional CRT. Rates of radiation oncologist-reported fair or poor cosmetic outcomes are higher with brachytherapy. We identified dosimetric parameters that predict reduced risk of adverse cosmetic outcome after brachytherapy-based APBI. Ipsilateral breast recurrence was equivalent for brachytherapy and 3-dimensional CRT.

Abstract P2-11-12: Prospective comparison of late toxicity and cosmetic outcome after accelerated partial breast irradiation with conformal external beam radiotherapy or single-entry multi-lumen intracavitary brachytherapy

Purpose/Objective(s):

To prospectively compare late toxicity after accelerated partial breast irradiation (APBI) with 3D-conformal external beam radiotherapy (3D-CRT) or single-entry multi-lumen intracavitary brachytherapy.

Patients/Methods:

Two hundred eighty-one patients with pTis or pT2N0 (≤3.0 cm) breast cancer treated with segmental mastectomy were prospectively enrolled on a multi-institution observational protocol from 12/2008 – 8/2014. Patients were enrolled and treated at primary, satellite, and affiliated academic institutions. APBI was delivered using 3D-CRT or with a Contura®, MammoSite®, or SAVI® brachytherapy catheter. 3D-CRT patients were treated to 34.0 Gy (7%) or 38.5 Gy (93%) at 3.4-3.85 Gy/fx BID and brachytherapy patients were treated to 34.0 Gy at 3.4 Gy/fx BID. Per protocol, patients were clinically evaluated at 2, 6, 12, 18, and 24 months and then annually. At each clinical evaluation the radiation oncologist scored cosmetic outcome (excellent/good/fair/poor according to the Harvard Cosmesis Scale), toxicity (seroma/infection/fat necrosis/pain/telangiectasia/radiation dermatitis/hyperpigmentation/hypopigmentation/fibrosis/induration/edema/other according to CTCAE v3.0) and recurrence status.

Results:

The median age was 61 years. Of 281 patients, 211 (75%) had invasive breast cancer and 70 (25%) had in situ disease. Among patients with invasive disease, 90% were HR+/HER2-, and among patients with in situ disease, 83% were HR+. APBI was delivered with 3D-CRT in 29 (10%) patients and with single-entry multi-lumen intracavitary brachytherapy in 252 (90%) patients. Among the brachytherapy patients, APBI was delivered with the SAVI®, Contura®, and MammoSite® devices in 176 (70%), 56 (22%), and 20 (8%) patients, respectively. With a median follow-up of 49 months, rates of Grade 1 (G1) and Grade 2-3 (G2-3) toxicity are:

 3D-CRTBrachytherapy   G1G2-3G1G2-3G1G2-3 N (%)N (%)N (%)N (%)  Fibrosis13 (46%)1 (4%)176 (72%)6 (2%)p=0.008p=0.54Fat Necrosis0 (0%)0 (0%)0 (0%)4 (2%)p=1.00p=1.00Telangiectasia6 (21%)1 (4%)44 (18%)5 (2%)p=0.61p=0.48Seroma2 (7%)1 (4%)135 (55%)12 (5%)p&lt;0.0001p=1.00

Mean skin dose of the maximally-irradiated 0.1 cc (D0.1cc) of skin was significantly higher in patients who developed telangiectasia (103.4% ± 16.1% compared to 96.5% ± 18.6% of prescription dose, p=0.007) and fibrosis (100.1% ± 15.5% compared to 92.8% ± 23.0% of prescription dose, p=0.02). Crude rates of fair or poor cosmetic outcome at 2-4 and 4-6 years were 6.9% and 14.8%, respectively, for 3D-CRT and 14.8% and 21.3%, respectively, for brachytherapy (p&gt;0.05 at both timepoints). Five-year recurrence-free survival was 96.3% with 3D-CRT and 96.1% for brachytherapy (p&gt;0.05).

Conclusion:

APBI with single-entry multi-lumen intracavitary brachytherapy is associated with increased rates of grade 1 fibrosis and seroma than APBI with 3D-CRT. Higher mean skin D0.1cc is associated with increased risk of telangiectasia and fibrosis. Despite increased low-grade fibrosis, there is no significant difference in radiation oncologist-reported fair or poor cosmetic outcome out to six years, or rate of five-year ipsilateral breast recurrence.

Citation Format: Stecklein SR, Babiera GV, Bedrosian I, Shaitelman SF, Ballo MT, Tereffe W, Arzu IY, Perkins GH, Strom EA, Reed VK, Dvorak T, Smith BD, Woodward WA, Hoffman KE, Schlembach PJ, Chronowski GM, Shah SJ, Kirsner SM, Nelson CL, Guerra W, Dibaj SS, Bloom ES. Prospective comparison of late toxicity and cosmetic outcome after accelerated partial breast irradiation with conformal external beam radiotherapy or single-entry multi-lumen intracavitary brachytherapy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-11-12.

Comparative Neurologic Outcomes of Salvage and Definitive Gamma Knife Radiosurgery for Glomus Jugulare: A 20-Year Experience

Objective  This case series investigates management of glomus jugulare (GJ) tumors utilizing definitive and salvage Gamma Knife stereotactic radiosurgery (GKSRS). Methods  A retrospective chart review was performed to collect data. Statistical analysis included patient, tumor, and treatment information. Results  From 1996 to 2013, 17 patients with GJ received GKSRS. Median age was 64 years (range, 27-76). GKSRS was delivered for definitive treatment in eight (47%) and salvage in nine (53%) patients. Median tumor volume was 9.8 cm ³ (range, 2.8-42 cm ³ ). Median dose was 15 Gy (range, 13-18 Gy). Median follow-up was 123 months (range, 38-238 months). Tumor size decreased in 10 (59%), stabilized in 6 (35%), and increased in 1 patient (6%). Overall neurological deficit improved in 53%, stabilized in 41%, and worsened in 6% of patients. Overall cause-specific survival was 100%, and actuarial local control was 94%. Eighty-eight percent of patients without prior resection experienced neurologic deficit improvement, while 25% of patients with prior resection experienced neurologic improvement ( p  = 0.02). Conclusion  Gamma Knife radiosurgery provides effective long-term control of GJ and overall improvement or stabilization of neurological deficit in most patients. Patients with prior resection are less likely to experience improvement of neurologic deficit.

Repeat Episcleral Plaque Brachytherapy: Clinical Outcomes in Patients Treated for Locally Recurrent Posterior Uveal Melanoma

PURPOSE

To report the outcomes of survival, local control, visual acuity, and eye retention in patients treated with repeat episcleral plaque brachytherapy (EPBT) for locally recurrent posterior uveal melanoma (PUM).

DESIGN

Retrospective, interventional case series.

METHODS

Setting: Institutional.

PATIENT POPULATION

A total of 1201 patients that underwent iodine-125 (I-125) EPBT as primary treatment for PUM between 1985 and 2015.

INCLUSION CRITERIA

Development of locally recurrent disease and retreatment with I-125 EPBT.

OBSERVATION PROCEDURES

Clinical records review.

MAIN OUTCOME MEASURES

Visual acuity, Kaplan-Meier estimates of survival, local control, metastasis, and loss of the eye over the duration of follow-up.

RESULTS

Twenty-seven patients (13 men) met our inclusion criteria. Median (range) follow-up from initial treatment was 100 months (14-365 months), while median time to local recurrence was 43 months (9-185 months). Median (range) follow-up after retreatment was 47 months (3-120 months). Kaplan-Meier estimate for local control at 5 years was 77.2% (95% confidence interval [CI], 53.29%-89.91%). All marginal recurrences were successfully retreated whereas 6 of 15 patients with central recurrence developed subsequent re-recurrence following salvage EPBT. Median (range) visual acuity was 20/70 (20/20 to counting fingers at 1 foot) at time of recurrence and declined to counting fingers (20/25 to hand motion) at the most recent follow-up examination. Kaplan-Meier estimate for absence of metastatic disease at 5 years was 78.5% (95% CI, 54.77%-90.70%).

CONCLUSIONS

Repeat I-125 EPBT offers a viable alternative to enucleation in patients with local recurrence of PUM, yielding high rates of local control with predictable decline in visual acuity.

Phase 1 adaptive dose-finding study of neoadjuvant gemcitabine combined with radiation therapy for patients with high-risk extremity and trunk soft tissue sarcoma

BACKGROUND

This study was performed to determine the maximum tolerated dose (MTD) of gemcitabine given concurrently with preoperative, fixed-dose external-beam radiation therapy (EBRT) for patients with resectable, high-risk extremity and trunk soft tissue sarcoma (STS).

METHODS

Gemcitabine was administered on days 1, 8, 22, 29, 43, and 50 with EBRT (50 Gy in 25 fractions over 5 weeks). The gemcitabine MTD was determined with a toxicity severity weight method (TSWM) incorporating 6 toxicity types. The TSWM is a Bayesian procedure that choses each cohort's dose to have a posterior mean total toxicity burden closest to a predetermined clinician-defined target. Clinicopathologic and outcome data were also collected.

RESULTS

Thirty-six patients completed the study. According to the TSWM, the gemcitabine MTD was 700 mg/m(2). At this dose level, 4 patients (24%) experienced grade 4 toxicity; no toxicity-related deaths occurred. All tumors were resected with microscopically negative margins. Pathologic responses of >90% tumor necrosis were achieved in 17 patients (47%); 14 (39%) had complete responses. With a median follow-up of 6.2 years, the 5-year locoregional recurrence-free survival, distant metastasis-free survival, and overall survival rates were 85%, 80%, and 86%, respectively.

CONCLUSIONS

The TSWM combines data from qualitatively different toxicities and can be used to determine the MTD for a drug given as part of a multimodality treatment. Neoadjuvant gemcitabine plus radiation therapy is feasible and safe in patients with high-risk extremity and trunk STS. Major pathologic responses can be achieved, and after complete resection, long-term clinical outcomes are encouraging.

Dosimetric impact of setup accuracy for an electron breast boost technique

PURPOSE

To determine the setup error on an electron breast boost technique using daily cone beam computed tomography (CBCT). Patient and setup attributes were studied as contributing factors to the accuracy.

METHODS AND MATERIALS

Reproducibility of a modified lateral decubitus position breast boost setup was verified for 33 patients using CBCT. Three-dimensional matching was performed between the CBCT and the initial planning CT for each boost fraction by matching the tumor bed and/or surgical clips. The dosimetric impact of the daily positioning error was achieved by rerunning the initial treatment plans incorporating the recorded shifts to study the dose differences. Breast compression, decubitus angle, tumor bed location and volume, and cup size were studied for their contribution to setup error.

RESULTS

The range of setup errors was: 1.5 cm anterior to 9 mm posterior, 1.3 cm superior to 2.3 cm inferior, and 3.2 cm medial to 2.4 cm lateral. Seven patients had setup errors that were ≥2-cm margin placed on the tumor bed and scar. Four of those 7 patients had unacceptable coverage as defined by the volume of the tumor bed plus scar that is covered by the 90% isodose line (V90) compared with the original plan. All other patients had no discernible difference in the coverage (V90). The use of compression, tumor bed location, or volumes >20 mL showed no effect on coverage.

CONCLUSIONS

In general, this study supported that a 2-cm margin was adequate (29 of 33 patients) when patients are treated under typical conditions. Care should be taken when high electron energies are selected because the coverage at depth is more difficult to maintain in the clinical environment.

Prospective peer review quality assurance for outpatient radiation therapy

PURPOSE

We implemented a peer review program that required presentation of all nonpalliative cases to a weekly peer review conference. The purpose of this review is to document compliance and determine how this program impacted care.

METHODS AND MATERIALS

A total of 2988 patients were eligible for peer review. Patient data were presented to a group of physicians, physicists, and dosimetrists, and the radiation therapy plan was reviewed. Details of changes made were documented within a quality assurance note dictated after discussion. Changes recommended by the peer review process were categorized as changes to radiation dose, target, or major changes.

RESULTS

Breast cancer accounted for 47.9% of all cases, followed in frequency by head-and-neck (14.8%), gastrointestinal (9.9%), genitourinary (9.3%), and thoracic (6.7%) malignancies. Of the 2988 eligible patients, 158 (5.3%) were not presented for peer review. The number of missed presentations decreased over time; 2007, 8.2%; 2008, 5.7%; 2009, 3.8%; and 2010, 2.7% (P < .001). The reason for a missed presentation was unknown but varied by disease site and physician. Of the 2830 cases presented for peer review, a change was recommended in 346 cases (12.2%) and categorized as a dose change in 28.3%, a target change in 69.1%, and a major treatment change in 2.6%. When examined by year of treatment the number of changes recommended decreased over time: 2007, 16.5%; 2008, 11.5%; 2009, 12.5%; and 2010, 7.8% (P < .001). The number of changes recommended varied by disease site and physician. The head-and-neck, gynecologic, and gastrointestinal malignancies accounted for the majority of changes made.

CONCLUSIONS

Compliance with this weekly program was satisfactory and improved over time. The program resulted in decreased treatment plan changes over time reflecting a move toward treatment consensus. We recommend that peer review be considered for patients receiving radiation therapy as it creates a culture where guideline adherence and discussion are part of normal practice.

A peer review quality assurance program for outpatient radiation treatments

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Background: Our outpatient radiation treatment centers implemented a peer review program in 2007 that required presentation of all definitive cases to a weekly peer review conference. The purpose of this review is to document compliance and determine how this program impacted care over 4 years. Methods: Between 9/2007 and 9/2011, 2,988 patients were eligible for peer review. Patient data was presented to a group of physicians, physicists, and dosimetrists via teleconferencing and the radiotherapy plan was reviewed. Details of any changes made to patient care were documented within a QA note dictated after discussion. Any changes recommended by the peer review process were categorized as changes to radiation dose, target, or major changes. Results: Breast cancer accounted for 47.9% of all cases, followed in frequency by H/N (14.8%), GI (9.9%), GU (9.3%), and thoracic (6.7%) malignancies. Of the 2,988 eligible patients, 158 (5.3%) were not presented for peer review. The number of missed presentations decreased over time; 2007-8.2%; 2008-5.7%; 2009-3.8%; and 2010-2.7% (p<0.001). The reason for a missed presentation was unknown, but varied by disease site and physician. Of the 2,830 cases presented for peer review, a change was recommended in 346 cases (12.2%) and categorized as a dose change in 28.3%, a target change in 69.1% and a major treatment change in 2.6%. When examined by year of treatment the number of changes recommended decreased over time: 2007-16.5%; 2008-11.5%; 2009-12.5%; and 2010-7.8% (p<0.001). The number of changes recommended varied by disease site and physician. H/N, GYN, and GI malignancies accounted for the majority of changes made. Conclusions: Compliance with this weekly peer review QA program was satisfactory and improved significantly over the 4 year study period. The QA program resulted in decreased treatment plan changes over time reflecting a move toward radiation treatment consensus and consistency. Weekly peer review directly improved care in all patients by creating a culture of QA where guideline adherence and discussion are part of normal practice.

Radiation therapy field extent for adjuvant treatment of axillary metastases from malignant melanoma

PURPOSE

To compare treatment-related outcomes and toxicity for patients with axillary lymph node metastases from malignant melanoma treated with postoperative radiation therapy (RT) to either the axilla only or both the axilla and supraclavicular fossa (extended field [EF]).

METHODS AND MATERIALS

The medical records of 200 consecutive patients treated with postoperative RT for axillary lymph node metastases from malignant melanoma were retrospectively reviewed. All patients received postoperative hypofractionated RT for high-risk features; 95 patients (48%) received RT to the axilla only and 105 patients (52%) to the EF.

RESULTS

At a median follow-up of 59 months, 111 patients (56%) had sustained relapse, and 99 patients (50%) had died. The 5-year overall survival, disease-free survival, and distant metastasis-free survival rates were 51%, 43%, and 46%, respectively. The 5-year axillary control rate was 88%. There was no difference in axillary control rates on the basis of the treated field (89% for axilla only vs. 86% for EF; p = 0.4). Forty-seven patients (24%) developed treatment-related complications. On both univariate and multivariate analyses, only treatment with EF irradiation was significantly associated with increased treatment-related complications.

CONCLUSIONS

Adjuvant hypofractionated RT to the axilla only for metastatic malignant melanoma with high-risk features is an effective method to control axillary disease. Limiting the radiation field to the axilla only produced equivalent axillary control rates to EF and resulted in lower treatment-related complication rates.

Biochemotherapy in patients with advanced head and neck mucosal melanoma

BACKGROUND

No systemic therapy regimen has been recognized as effective for metastatic mucosal melanoma of the head and neck. We retrospectively analyzed the effectiveness of biochemotherapy in patients with advanced head and neck mucosal melanoma.

METHODS

We evaluated the medical records of 15 patients at our institution who had received various biochemotherapy regimens for advanced head and neck mucosal melanoma.

RESULTS

After a median follow-up duration of 13 months, 3 patients (20%) had partial response, and 4 patients (27%) had complete response. The median time to disease progression for all 15 patients was 10 months. The median overall survival duration for all patients was 22 months.

CONCLUSIONS

Although this was a small study, our results, especially the high complete response and overall response rates, indicate that biochemotherapy for advanced head and neck mucosal melanoma should be considered as a systemic treatment option for patients with this aggressive malignancy.

Excellent Local Control Rates and Distinctive Patterns of Failure in Myxoid Liposarcoma Treated With Conservation Surgery and Radiotherapy

PURPOSE

To evaluate the local control rates and patterns of metastatic relapse in patients with localized myxoid liposarcoma treated with conservation surgery and radiotherapy (RT).

PATIENTS AND METHODS

Between 1960 and 2003, 127 patients with non-metastatic myxoid liposarcoma were treated with conservation surgery and RT at our institution. The median patient age was 39 years (range, 14-79 years). Of the 127 patients, 46% underwent preoperative RT (median dose, 50 Gy) and 54% underwent postoperative RT (median dose, 60 Gy). Also, 28% received doxorubicin-based chemotherapy as a part of their treatment.

RESULTS

The median follow-up was 9.1 years. The overall survival rate at 5 and 10 years was 87% and 79%, respectively. The corresponding disease-free survival rates were 81% and 73%. The local control rate at > or =5 years was 97%. The actuarial rate of distant metastases at 5 and 10 years was 15% and 24%, respectively. Of the 27 patients who developed distant metastases, 48% did so in the retroperitoneum, 22% in other extrapulmonary soft tissues, 22% in the lung, 15% in bone, and 4% in the liver.

CONCLUSION

The results of our study have shown that RT and conservation surgery for localized myxoid liposarcoma provide excellent local control. Distant metastatic relapse tended to occur in the retroperitoneum and other nonpulmonary soft tissues. Therefore, staging and surveillance imaging should include the abdomen and pelvis, as well as the thorax, for patients with localized myxoid liposarcoma.

Long-term results of prospective trial of surgery alone with selective use of radiation for patients with T1 extremity and trunk soft tissue sarcomas

OBJECTIVE

We conducted a prospective trial to define the local recurrence rates for selected patients with T1 soft tissue sarcomas (STS) treated by surgery alone.

SUMMARY BACKGROUND DATA

Retrospective data suggest that some patients with small STS can be safely treated by surgery alone. There are no defined criteria to select patients for such treatment.

METHODS

Patients with T1 primary STS were treated with function-preserving surgery and microscopic assessment of surgical margins. Postoperative external-beam radiation was employed selectively for patients with microscopically positive (R1) final surgical margins. Patients who underwent resection with microscopically negative (R0) final margins did not receive radiotherapy.

RESULTS

Eighty-eight eligible and evaluable patients were entered on this protocol between March 1996 and April 2002. Tumor sites included the extremities (n=60), and trunk (n=26). Fifty-one patients (58%) had high-grade STS; 60 (68%) had superficial (T1a) disease. Fourteen patients (16%) underwent R1 resection and were treated with postoperative radiation; 74 (84%) underwent R0 resection and were treated by surgery alone. The median follow-up was 75 months. Isolated local recurrences were observed in 11 patients (13%; 6 in R1 arm, 5 in R0 arm). In the R0 surgery-alone arm, the cumulative incidence rates of local recurrence at 5 and 10 years were 7.9% and 10.6%, respectively; and the 5- and 10-year sarcoma-specific death rates were 3.2% and 3.2%.

CONCLUSION

Selected patients with primary T1 STS of the extremity and trunk can be treated by R0 surgery alone with acceptable local control and excellent long-term survival.

Long-term outcomes for synovial sarcoma treated with conservation surgery and radiotherapy

PURPOSE

To evaluate prognostic factors and treatment outcomes in patients with localized synovial sarcoma treated with conservation surgery and radiotherapy (RT).

METHODS AND MATERIALS

Between 1960 and 2003, 150 patients with nonmetastatic synovial sarcoma were treated with conservation surgery and RT. The majority of patients (81%) were aged >20 years. Sixty-eight percent received postoperative RT, and 32% received preoperative RT. Forty-eight percent received adjuvant chemotherapy.

RESULTS

Median follow-up was 13.2 years. Overall survival (OS) rates at 5, 10, and 15 years were 76%, 57%, and 51%, respectively. Corresponding disease-free survival (DFS) rates were 59%, 52%, and 52%, respectively. Tumor size >5 cm predicted worse OS, DFS, disease-specific survival (DSS), and higher rate of distant metastases (DM). Age >20 years predicted worse DFS and DSS but not OS. Local control (LC) was 82% at 10 years. Positive or unknown resection margins predicted inferior LC rates. Forty-four percent developed DM by 10 years. Only 1% developed nodal metastases. Analysis of outcomes by treatment decade showed no significant differences with respect to LC and DM rates.

CONCLUSIONS

Synovial sarcoma is adequately controlled at the primary site by conservation surgery and RT. Elective nodal irradiation is not indicated. Rates of development of DM and subsequent death from disease remain high, with no significant improvement in outcomes for this disease in the past four decades.

Optimizing Treatment of Desmoid Tumors

Purpose

This study compared a large series of desmoid patients treated at a single institution to a previously published series from the same institution to determine if patient population characteristics, treatment approaches, and clinical outcomes had undergone change over the two study periods.

Materials and Methods

Data from a prospective soft tissue tumor database was used to analyze clinical courses of 189 desmoid patients treated at The University of Texas M.D. Anderson Cancer Center (UTMDACC) from 1995 to 2005 as compared with 189 UTMDACC desmoid patients treated between 1965 and 1994.

Results

A nearly three-fold increase in annualized UTMDACC desmoid referral volume with significantly higher percentages and numbers of primary desmoid tumor referrals to UTMDACC was observed in the most recent study period. Significantly increased systemic therapy use and decreased reliance on surgery alone was observed more recently. While the recent series patients had higher rates of macroscopic residual disease and equivalent rates of positive microscopic margins after definitive surgery, the estimated 5-year local recurrence rate of 20% was improved compared with the 30% rate observed in the earlier series.

Conclusion

Increased awareness of the complex multidisciplinary management needed for desmoid tumor control may underlie significantly increased numbers of referrals to UTMDACC, especially primary untreated desmoids. Increased neoadjuvant treatments may be associated with improved desmoid patient outcomes. These trends should be supported, particularly if personalized molecular-based therapies are to be rapidly and effectively deployed for the benefit of those afflicted by this rare and potentially debilitating disease.

Management of locally recurrent soft-tissue sarcoma after prior surgery and radiation therapy

PURPOSE

The aim of this study was to evaluate outcome and treatment toxicity after wide local re-excision (WLE), with or without additional radiation therapy, for patients with isolated first local recurrence of soft-tissue sarcoma arising within a previously irradiated field.

METHODS

A retrospective review was performed of 62 consecutive patients. All patients underwent prior resection and external beam radiation. For recurrent disease, 25 patients were treated with WLE alone, and 37 patients were treated with WLE and additional radiation (45- 64 Gy). In 33 patients, the radiation was delivered via an afterloaded brachytherapy, single-plane implant.

RESULTS

The 5-year disease specific and distant metastasis-free survival rates were 65% and 73%, respectively. Local control (LC) at 5 years was 51%, and on multivariate analysis, a positive surgical resection margin (p< 0.001) was associated with a lower rate of LC. Reirradiation was not associated with improved LC; however complications requiring outpatient or surgical management were more common in patients who had undergone reirradiation (80% vs. 17%, p < 0.001). Amputation was also more common in the subgroup of patients who underwent extremity reirradiation (35% with radiation vs. 11% without, p = 0.05), although only one amputation was performed to resolve a treatment complication.

CONCLUSION

Conservative surgery alone results in LC in a minority of patients who have failed locally after previous excision and external beam radiation. Although selection biases and small patient numbers confound the analysis, local treatment intensification with additional radiation does not clearly improve outcome after surgical excision alone, and is associated with an increase in complications.

Periosteal margin in soft-tissue sarcoma

BACKGROUND

Soft-tissue sarcomas frequently rest in contact with bone. The purpose of the study was to evaluate the risk of local recurrence for sarcomas adjacent to bone and to determine whether the periosteum provides an adequate margin of resection.

METHODS

Fifty patients with soft-tissue sarcomas abutting bone were treated at a single institution between 1990 and 2004. All patients had high-grade, T2 (>5 cm), nonmetastatic disease in the lower extremity. Bone contact was verified by preoperative magnetic resonance imaging (MRI) and/or computed tomography (CT) scans. Forty-three of 50 patients received preoperative radiation with a mean dose of 50 Gy. In 11 cases a composite resection of bone and soft tissue was performed. In 39 cases the excision involved only soft tissue.

RESULTS

True bone invasion was verified by histopathologic examination in 3 of 50 cases (6%). Local recurrence in the soft tissues developed in 8 of 50 (16%) patients. In no case did the recurrence involve destruction of cortical bone or erosion into bone. The recurrent tumor resided against the region of previous bone contact in 1 of 8 cases. There was no statistically significant difference in local recurrence between patients who had composite bone resection and patients who had soft-tissue resection only (P = .87).

CONCLUSIONS

Relatively few sarcomas are able to penetrate cortical bone. Composite bone and soft-tissue resections are indicated primarily for frank bone invasion. In the absence of this, the periosteum is an adequate surgical margin for sarcomas treated with wide excision and radiation.

Survival in patients with synovial sarcoma of the head and neck: Association with tumor location, size, and extension

BACKGROUND

The medical literature on synovial sarcoma (SS) of the head and neck region is limited. Thus, we determined whether clinical characteristics and treatment were associated with recurrence and survival rates in patients with SS of the head and neck.

METHODS

We retrospectively identified patients with a pathologic diagnosis of SS of the head and neck at our institution (a large tertiary comprehensive cancer center) and compared recurrence and survival rates by clinical characteristics and treatment.

RESULTS

Forty patients with SS of the head and neck were identified from 1945 to 2004 (first case in 1968), representing <5% of all head and neck sarcomas seen at our institution during this time period. Twenty-three patients (58%) had the monophasic histologic subtype, 15 (38%) biphasic, and 2 unspecified. Most patients were male (73%), with a median age of 29 years. SS tumors were most commonly located in the neck (60%); thus, the most common symptoms were a neck mass and neck pain. No patients reported a history of radiation exposure. Higher disease-specific and overall survival rates were associated with upper aerodigestive tract location, tumors of < or =5 cm, and tumors did not extend into bone. Patients treated with surgery and adjuvant radiotherapy had higher survival and lower recurrence rates than did those treated with surgery alone or a combination of surgery, radiotherapy, and chemotherapy. This difference was not significant, and the subgroups were small, with substantial confounding by adverse prognostic factors.

CONCLUSIONS

SS of the head and neck is extremely rare, and our results should be viewed with caution given the relatively small group size and treatment over a 36-year period. Survival rates were associated with tumor location, size, and extension. Treatment of SS of the head and neck should be directed toward complete surgical resection. Given the known sensitivity of SS to contemporary chemotherapy, a multimodality approach should be considered in the perioperative setting, especially in high risk patients.