Total Neoadjuvant Therapy in Rectal Cancer: Multi-center Comparison of Induction Chemotherapy and Long-Course Chemoradiation Versus Short-Course Radiation and Consolidative Chemotherapy.

BACKGROUND: Total neoadjuvant therapy for locally advanced rectal cancer may include induction chemotherapy and chemoradiation or short-course radiotherapy and consolidative chemotherapy. METHODS: Patients with clinical stage 2 or 3 rectal cancer who received induction chemotherapy followed by long-course chemoradiation at the University of Colorado (2016-2020) or short-course radiotherapy followed by consolidative chemotherapy at Washington University (2017-2020) were assessed. RESULTS: Eighty-four patients received induction chemotherapy and chemoradiation and 83 received short-course radiotherapy and consolidative chemotherapy. Among patients with complete re-staging evaluation, clinical complete response rates were similar, 49% (18/37) and 53% (44/83), respectively (p = 0.659). In the induction chemotherapy and chemoradiation group, 80% (n = 67) underwent surgery and 28% (n = 19) achieved a pathologic complete response. In the short-course radiotherapy and consolidative chemotherapy group, 44 (53%) patients underwent surgery and 11% (n = 5) had a pathologic complete response. Overall, a complete response was observed in 43% (n = 36) of patients who received induction chemotherapy and chemoradiation compared to 53% (n = 44) who received short-course radiotherapy and consolidative chemotherapy (p = 0.189). Perioperative outcomes were similar in patients who received induction chemotherapy and chemoradiation compared to short-course radiotherapy and consolidative chemotherapy: intraoperative complications (2% vs 7%), complete mesorectal specimen (85% vs 84%), anastomotic leak (9% vs 7%), organ/space infection (9% vs 5%), readmission (19% vs 21%), and reoperation (8% vs 9%), respectively (all p > 0.05). CONCLUSIONS: In patients with clinical stage 2 or 3 rectal cancer, total neoadjuvant therapy with either induction chemotherapy and chemoradiation or short-course radiotherapy followed by consolidative chemotherapy were associated with similar perioperative morbidity and complete response rates.

Cardiac metabolic changes on 18 F-positron emission tomography after thoracic radiotherapy predict for overall survival in esophageal cancer patients.

PURPOSE: Heart doses have been shown to be predictive of cardiac toxicity and overall survival (OS) for esophageal cancer patients. There is potential for functional imaging to provide valuable cardiac information. The purpose of this study was to evaluate the cardiac metabolic dose-response using 18 F-deoxyglucose (FDG)-PET and to assess whether standard uptake value (SUV) changes in the heart were predictive of OS. METHODS: Fifty-one patients with esophageal cancer treated with radiation who underwent pre- and post-treatment FDG-PET scans were retrospectively evaluated. Pre- and post-treatment PET-scans were rigidly registered to the planning CT for each patient. Pre-treatment to post-treatment absolute mean SUV (SUVmean) changes in the heart were calculated to assess dose-response. A dose-response curve was generated by binning each voxel in the heart into 10 Gy dose-bins and analyzing the SUVmean changes in each dose-bin. Multivariate cox proportional hazard models were used to assess whether pre-to-post treatment cardiac SUVmean changes predicted for OS. RESULTS: The cardiac dose-response curve demonstrated a trend of increasing cardiac SUV changes as a function of dose with an average increase of 0.044 SUV for every 10 Gy dose bin. In multivariate analysis, disease stage and SUVmean change in the heart were predictive (p < 0.05) for OS. CONCLUSIONS: Changes in pre- to post-treatment cardiac SUV were predictive of OS with patients having a higher pre- to post-treatment cardiac SUV change surviving longer.

Rectal Cancer: Clinical and Molecular Predictors of a Complete Response to Total Neoadjuvant Therapy.

BACKGROUND: Total neoadjuvant therapy in rectal cancer may increase pathological complete response rates, potentially allowing for a nonoperative approach. OBJECTIVE: The objective of this study was to identify patient and tumor characteristics that predict a complete response following total neoadjuvant therapy. DESIGN: This was a retrospective cohort study. SETTINGS: This study was conducted at a university-based National Cancer Institute-designated Comprehensive Cancer Center. PATIENTS: The patients include those with stage 2 or 3 rectal adenocarcinoma. INTERVENTIONS: Interventions included total neoadjuvant therapy, total mesorectal excision, and nonoperative management. MAIN OUTCOME MEASURES: Complete response was defined as either patients with a clinical complete response undergoing nonoperative management who remained cancer-free or patients undergoing surgery with a pathological complete response. RESULTS: Among 102 patients, median age was 54 years, 69% were male, median carcinoembryonic antigen level was 3.0 ng/mL, and the median distance of the tumor above the anorectal ring was 3 cm. Thirty-eight (37%) patients had a complete response, including 15 of 18 (83%) nonoperative patients who remained cancer free at a median of 22 months (range, 7-48 months) and 23 of 84 (27%) patients who underwent surgery and had a pathological complete response. The incomplete response group consisted of 61 patients who underwent initial surgery and 3 nonoperative patients with regrowth. There were no differences in gender, T-stage, or tumor location between groups. Younger age (median, 49 vs 55 years), normal carcinoembryonic antigen (71% vs 41%), clinical node-negative (24% vs 9%), smaller tumors (median 3.9 vs 5.4 cm), and wild-type p53 (79% vs 47%) and SMAD4 (100% vs 81%) were more likely to have a complete response (all p < 0.05). LIMITATIONS: This was a retrospective study with a small sample size. CONCLUSIONS: In patients with rectal cancer treated with total neoadjuvant therapy, more than one-third will achieve a pathological complete response or sustained clinical complete response with nonoperative management, making oncological resection superfluous in these patients. Smaller, wild-type p53 and SMAD4, and clinically node-negative cancers are predictive features of a complete response. See Video Abstract at http://links.lww.com/DCR/B889 . CNCER DE RECTO PREDICTORES CLNICOS Y MOLECULARES DE UNA RESPUESTA COMPLETA A LA TERAPIA NEOADYUVANTE TOTAL: ANTECEDENTES:La terapia neoadyuvante total en el cáncer de recto puede aumentar las tasas de respuesta patológica completa y permitir potencialmente un enfoque no quirúrgico.OBJETIVO:El objetivo fue identificar las características tanto del paciente y del tumor que logren predecir una respuesta completa después de la terapia neoadyuvante total.DISEÑO:Este fue un estudio de cohorte retrospectivo.AJUSTES:Este estudio se realizó en un Centro Integral de Cáncer designado por el Instituto Nacional del Cáncer con sede universitaria.PACIENTES:Los pacientes incluyen aquellos con adenocarcinoma de recto en estadio 2 o 3.INTERVENCIONES:Terapia neoadyuvante total, escisión total del mesorrecto, manejo conservador no quirúrgico.PRINCIPALES MEDIDAS DE RESULTADO:La respuesta completa se definió como pacientes con una respuesta clínica completa sometidos a tratamiento no quirúrgico que permanecieron libres de cáncer o pacientes sometidos a cirugía con una respuesta patológica completa.RESULTADOS:Entre 102 pacientes, la mediana de edad fue de 54 años, el 69% fueron hombres, la mediana del nivel de antígeno carcinoembrionario fue de 3.0 ng/ml y la mediana de la distancia del tumor por encima del anillo anorrectal fue de 3 cm. Thirty-eight (37%) pacientes tuvieron una respuesta completa que incluyó a 15 de 18 (83%) pacientes con manejo no operatorio y que permanecieron libres de cáncer en una mediana de 22 meses (rango 7- 48 meses) y 23 de 84 (27%) pacientes que fueron sometidos a cirugía y tuvieron una respuesta patológica completa. El grupo de respuesta incompleta consistió en 61 pacientes que fueron sometidos inicialmente a cirugía y 3 pacientes no quirúrgicos con recrecimiento. No se encontró diferencias de género, estadio T o ubicación del tumor entre los grupos. Edad más joven (mediana 49 frente a 55), antígeno carcinoembrionario normal (71% frente a 41%), ganglios clínicos negativos (24% frente a 9%), tumores más pequeños (mediana de 3,9 frente a 5,4 cm) y p53 de tipo salvaje (79 % vs 47%) y SMAD4 (100% vs 81%) tenían más probabilidades de tener una respuesta completa (todos p < 0,05).LIMITACIONES:Este fue un estudio retrospectivo y con un tamaño de muestra pequeño.CONCLUSIONES:En pacientes con cáncer de recto tratados con terapia neoadyuvante total, más de un tercio logrará una respuesta patológica completa o una respuesta clínica completa sostenida con manejo no operatorio, logrando que la resección oncológica sea superflua en estos pacientes. Los cánceres más pequeños, clínicamente con ganglios negativos, con p53 de tipo salvaje y SMAD4, son características predictoras de una respuesta completa. Consulte Video Resumen en http://links.lww.com/DCR/B889 . (Traducción-Dr. Osvaldo Gauto ).

MR-Guided Radiation Therapy With Concurrent Gemcitabine/Nab-Paclitaxel Chemotherapy in Inoperable Pancreatic Cancer: A TITE-CRM Phase I Trial.

PURPOSE: Ablative radiation therapy for borderline resectable or locally advanced pancreatic ductal adenocarcinoma (BR/LA-PDAC) may limit concurrent chemotherapy dosing and usually is only safely deliverable to tumors distant from gastrointestinal organs. Magnetic resonance guided radiation therapy may safely permit radiation and chemotherapy dose escalation. METHODS AND MATERIALS: We conducted a single-arm phase I study to determine the maximum tolerated dose of ablative hypofractionated radiation with full-dose gemcitabine/nab-paclitaxel in patients with BR/LA-PDAC. Patients were treated with gemcitabine/nab-paclitaxel (1000/125 mg/m2) x 1c then concurrent gemcitabine/nab-paclitaxel and radiation. Gemcitabine/nab-paclitaxel and radiation doses were escalated per time-to-event continual reassessment method from 40 to 45 Gy 25 fxs with chemotherapy (600-800/75 mg/m2) to 60 to 67.5 Gy/15 fractions and concurrent gemcitabine/nab-paclitaxel (1000/100 mg/m2). The primary endpoint was maximum tolerated dose of radiation as defined by 60-day dose limiting toxicity (DLT). DLT was treatment-related G5, G4 hematologic, or G3 gastrointestinal requiring hospitalization >3 days. Secondary endpoints included resection rates, local progression free survival (LPFS), distant metastasis free survival (DMFS), and overall survival (OS). RESULTS: Thirty patients enrolled (March 2015-February 2019), with 26 evaluable patients (2 progressed before radiation, 1 was determined ineligible for radiation during planning, 1 withdrew consent). One DLT was observed. The DLT rate was 14.1% (3.3%-24.9%) with a maximum tolerated dose of gemcitabine/nab-paclitaxel (1000/100 mg/m2) and 67.5 Gy/15 fractions. At a median follow-up of 40.6 months for living patients the median OS was 14.5 months (95% confidence interval [CI], 10.9-28.2 months). The median OS for patients with Eastern Collaborative Oncology Group 0 and carbohydrate antigen 19-9 <90 were 34.1 (95% CI, 13.6-54.1) and 43.0 (95% CI, 8.0-not reached) months, respectively. Two-year LPFS and DMFS were 85% (95% CI, 63%-94%) and 57% (95% CI, 34%-73%), respectively. CONCLUSIONS: Full-dose gemcitabine/nab-paclitaxel with ablative magnetic resonance guided radiation therapy dosing is safe in patients with BR/LA-PDAC, with promising LPFS and DMFS.

Consensus Quality Measures and Dose Constraints for Rectal Cancer From the Veterans Affairs Radiation Oncology Quality Surveillance Program and American Society for Radiation Oncology (ASTRO) Expert Panel.

PURPOSE: Ensuring high quality, evidence-based radiation therapy for patients with cancer is of the upmost importance. To address this need, the Veterans Affairs (VA) Radiation Oncology Program partnered with the American Society for Radiation Oncology and established the VA Radiation Oncology Quality Surveillance program. As part of this ongoing effort to provide the highest quality of care for patients with rectal cancer, a blue-ribbon panel comprised of rectal cancer experts was formed to develop clinical quality measures. METHODS AND MATERIALS: The Rectal Cancer Blue Ribbon panel developed quality, surveillance, and aspirational measures for (a) initial consultation and workup, (b) simulation, treatment planning, and treatment, and (c) follow-up. Twenty-two rectal cancer specific measures were developed (19 quality, 1 aspirational, and 2 surveillance). In addition, dose-volume histogram constraints for conventional and hypofractionated radiation therapy were created. CONCLUSIONS: The quality measures and dose-volume histogram for rectal cancer serves as a guideline to assess the quality of care for patients with rectal cancer receiving radiation therapy. These quality measures will be used for quality surveillance for veterans receiving care both inside and outside the VA system to improve the quality of care for these patients.

Nonoperative Rectal Cancer Management With Short-Course Radiation Followed by Chemotherapy: A Nonrandomized Control Trial.

PURPOSE: Short-course radiation therapy (SCRT) and nonoperative management are emerging paradigms for rectal cancer treatment. This clinical trial is the first to evaluate SCRT followed by chemotherapy as a nonoperative treatment modality. METHODS: Patients with nonmetastatic rectal adenocarcinoma were treated on the single-arm, Nonoperative Radiation Management of Adenocarcinoma of the Lower Rectum study of SCRT followed by chemotherapy. Patients received 25 Gy in 5 fractions to the pelvis followed by FOLFOX ×8 or CAPOX ×5 cycles. Patients with clinical complete response (cCR) underwent nonoperative surveillance. The primary end point was cCR at 1 year. Secondary end points included safety profile and anorectal function. RESULTS: From June 2016 to March 2019, 19 patients were treated (21% stage I, 32% stage II, and 47% stage III disease). At a median follow-up of 27.7 months for living patients, the 1-year cCR rate was 68%. Eighteen of 19 patients are alive without evidence of disease. Patients with cCR versus without had improved 2-year disease-free survival (93% vs 67%; P = .006), distant metastasis-free survival (100% vs 67%; P = .03), and overall survival (100% vs 67%; P = .03). Involved versus uninvolved circumferential resection margin on magnetic resonance imaging was associated with less initial cCR (40% vs 93%; P = .04). Anorectal function by Functional Assessment of Cancer Therapy-Colorectal cancer score at 1 year was not different than baseline. There were no severe late effects. CONCLUSIONS: Treatment with SCRT and chemotherapy resulted in high cCR rate, intact anorectal function, and no severe late effects. NCT02641691.

Magnetic resonance biomarkers in radiation oncology: The report of AAPM Task Group 294.

PURPOSE: A magnetic resonance (MR) biologic marker (biomarker) is a measurable quantitative characteristic that is an indicator of normal biological and pathogenetic processes or a response to therapeutic intervention derived from the MR imaging process. There is significant potential for MR biomarkers to facilitate personalized approaches to cancer care through more precise disease targeting by quantifying normal versus pathologic tissue function as well as toxicity to both radiation and chemotherapy. Both of which have the potential to increase the therapeutic ratio and provide earlier, more accurate monitoring of treatment response. The ongoing integration of MR into routine clinical radiation therapy (RT) planning and the development of MR guided radiation therapy systems is providing new opportunities for MR biomarkers to personalize and improve clinical outcomes. Their appropriate use, however, must be based on knowledge of the physical origin of the biomarker signal, the relationship to the underlying biological processes, and their strengths and limitations. The purpose of this report is to provide an educational resource describing MR biomarkers, the techniques used to quantify them, their strengths and weakness within the context of their application to radiation oncology so as to ensure their appropriate use and application within this field.

Adaptive Radiation Therapy (ART) Strategies and Technical Considerations: A State of the ART Review From NRG Oncology.

The integration of adaptive radiation therapy (ART), or modifying the treatment plan during the treatment course, is becoming more widely available in clinical practice. ART offers strong potential for minimizing treatment-related toxicity while escalating or de-escalating target doses based on the dose to organs at risk. Yet, ART workflows add complexity into the radiation therapy planning and delivery process that may introduce additional uncertainties. This work sought to review presently available ART workflows and technological considerations such as image quality, deformable image registration, and dose accumulation. Quality assurance considerations for ART components and minimum recommendations are described. Personnel and workflow efficiency recommendations are provided, as is a summary of currently available clinical evidence supporting the implementation of ART. Finally, to guide future clinical trial protocols, an example ART physician directive and a physics template following standard NRG Oncology protocol is provided.

Radiation Therapy for Rectal Cancer: Executive Summary of an ASTRO Clinical Practice Guideline.

PURPOSE: This guideline reviews the evidence and provides recommendations for the indications and appropriate technique and dose of neoadjuvant radiation therapy (RT) in the treatment of localized rectal cancer. METHODS: The American Society for Radiation Oncology convened a task force to address 4 key questions focused on the use of RT in preoperative management of operable rectal cancer. These questions included the indications for neoadjuvant RT, identification of appropriate neoadjuvant regimens, indications for consideration of a nonoperative or local excision approach after chemoradiation, and appropriate treatment volumes and techniques. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength. RESULTS: Neoadjuvant RT is recommended for patients with stage II-III rectal cancer, with either conventional fractionation with concurrent 5-FU or capecitabine or short-course RT. RT should be performed preoperatively rather than postoperatively. Omission of preoperative RT is conditionally recommended in selected patients with lower risk of locoregional recurrence. Addition of chemotherapy before or after chemoradiation or after short-course RT is conditionally recommended. Nonoperative management is conditionally recommended if a clinical complete response is achieved after neoadjuvant treatment in selected patients. Inclusion of the rectum and mesorectal, presacral, internal iliac, and obturator nodes in the clinical treatment volume is recommended. In addition, inclusion of external iliac nodes is conditionally recommended in patients with tumors invading an anterior organ or structure, and inclusion of inguinal and external iliac nodes is conditionally recommended in patients with tumors involving the anal canal. CONCLUSIONS: Based on currently published data, the American Society for Radiation Oncology task force has proposed evidence-based recommendations regarding the use of RT for rectal cancer. Future studies will look to further personalize treatment recommendations to optimize treatment outcomes and quality of life.