Association of Radiotherapy Duration With Clinical Outcomes in Patients With Esophageal Cancer Treated in NRG Oncology Trials: A Secondary Analysis of NRG Oncology Randomized Clinical Trials

Importance

For many types of epithelial malignant neoplasms that are treated with definitive radiotherapy (RT), treatment prolongation and interruptions have an adverse effect on outcomes.

Objective

To analyze the association between RT duration and outcomes in patients with esophageal cancer who were treated with definitive chemoradiotherapy (CRT).

Design, Setting, and Participants

This study was an unplanned, post hoc secondary analysis of 3 prospective, multi-institutional phase 3 randomized clinical trials (Radiation Therapy Oncology Group [RTOG] 8501, RTOG 9405, and RTOG 0436) of the National Cancer Institute-sponsored NRG Oncology (formerly the National Surgical Adjuvant Breast and Bowel Project, RTOG, and Gynecologic Oncology Group). Enrolled patients with nonmetastatic esophageal cancer underwent definitive CRT in the trials between 1986 and 2013, with follow-up occurring through 2014. Data analyses were conducted between March 2022 to February 2023.

Exposures

Treatment groups in the trials used standard-dose RT (50 Gy) and concurrent chemotherapy.

Main Outcomes and Measures

The outcomes were local-regional failure (LRF), distant failure, disease-free survival (DFS), and overall survival (OS). Multivariable models were used to examine the associations between these outcomes and both RT duration and interruptions. Radiotherapy duration was analyzed as a dichotomized variable using an X-Tile software to choose a cut point and its median value as a cut point, as well as a continuous variable.

Results

The analysis included 509 patients (median [IQR] age, 64 [57-70] years; 418 males [82%]; and 376 White individuals [74%]). The median (IQR) follow-up was 4.01 (2.93-4.92) years for surviving patients. The median cut point of RT duration was 39 days or less in 271 patients (53%) vs more than 39 days in 238 patients (47%), and the X-Tile software cut point was 45 days or less in 446 patients (88%) vs more than 45 days in 63 patients (12%). Radiotherapy interruptions occurred in 207 patients (41%). Female (vs male) sex and other (vs White) race and ethnicity were associated with longer RT duration and RT interruptions. In the multivariable models, RT duration longer than 45 days was associated with inferior DFS (hazard ratio [HR], 1.34; 95% CI, 1.01-1.77; P = .04). The HR for OS was 1.33, but the results were not statistically significant (95% CI, 0.99-1.77; P = .05). Radiotherapy duration longer than 39 days (vs ≤39 days) was associated with a higher risk of LRF (HR, 1.32; 95% CI, 1.06-1.65; P = .01). As a continuous variable, RT duration (per 1 week increase) was associated with DFS failure (HR, 1.14; 95% CI, 1.01-1.28; P = .03). The HR for LRF 1.13, but the result was not statistically significant (95% CI, 0.99-1.28; P = .07).

Conclusions and Relevance

Results of this study indicated that in patients with esophageal cancer receiving definitive CRT, prolonged RT duration was associated with inferior outcomes; female patients and those with other (vs White) race and ethnicity were more likely to have longer RT duration and experience RT interruptions. Radiotherapy interruptions should be minimized to optimize outcomes.

Randomized Phase IIB Trial of Proton Beam Therapy Versus Intensity-Modulated Radiation Therapy for Locally Advanced Esophageal Cancer

PURPOSE

Whether dosimetric advantages of proton beam therapy (PBT) translate to improved clinical outcomes compared with intensity-modulated radiation therapy (IMRT) remains unclear. This randomized trial compared total toxicity burden (TTB) and progression-free survival (PFS) between these modalities for esophageal cancer.

METHODS

This phase IIB trial randomly assigned patients to PBT or IMRT (50.4 Gy), stratified for histology, resectability, induction chemotherapy, and stage. The prespecified coprimary end points were TTB and PFS. TTB, a composite score of 11 distinct adverse events (AEs), including common toxicities as well as postoperative complications (POCs) in operated patients, quantified the extent of AE severity experienced over the duration of 1 year following treatment. The trial was conducted using Bayesian group sequential design with three planned interim analyses at 33%, 50%, and 67% of expected accrual (adjusted for follow-up).

RESULTS

This trial (commenced April 2012) was approved for closure and analysis upon activation of NRG-GI006 in March 2019, which occurred immediately prior to the planned 67% interim analysis. Altogether, 145 patients were randomly assigned (72 IMRT, 73 PBT), and 107 patients (61 IMRT, 46 PBT) were evaluable. Median follow-up was 44.1 months. Fifty-one patients (30 IMRT, 21 PBT) underwent esophagectomy; 80% of PBT was passive scattering. The posterior mean TTB was 2.3 times higher for IMRT (39.9; 95% highest posterior density interval, 26.2-54.9) than PBT (17.4; 10.5-25.0). The mean POC score was 7.6 times higher for IMRT (19.1; 7.3-32.3) versus PBT (2.5; 0.3-5.2). The posterior probability that mean TTB was lower for PBT compared with IMRT was 0.9989, which exceeded the trial's stopping boundary of 0.9942 at the 67% interim analysis. The 3-year PFS rate (50.8% v 51.2%) and 3-year overall survival rates (44.5% v 44.5%) were similar.

CONCLUSION

For locally advanced esophageal cancer, PBT reduced the risk and severity of AEs compared with IMRT while maintaining similar PFS.

Anticancer therapy and lung injury: molecular mechanisms

INTRODUCTION

Chemotherapy and radiation therapy are two mainstream strategies applied in the treatment of cancer that is not operable. Patients with hematological or solid tumor malignancies substantially benefit from chemotherapeutic drugs and/or ionizing radiation delivered to the site of malignancy. However, considerable adverse effects, including lung inflammation and fibrosis, are associated with the use of these treatment modalities. Areas covered: As we move toward the era of precision health, we are compelled to understand the molecular basis of chemoradiation-induced pathological lung remodeling and to develop effective treatment strategies that mitigate the development of chronic lung disease (i.e. fibrosis) in cancer patients. The review discusses chemotherapeutic agents that are reported to induce or associate with acute and/or chronic lung injury. Expert commentary: There is a need to molecularly understand how chemotherapeutic drugs induce or associate with respiratory toxicities and whether such characteristics are inherently related to their antitumor effect or are collateral. Once such mechanisms have been identified and/or fully characterized, they may be able to guide disease-management decisions including effective intervention strategies for the adverse effects. In the meantime, radiation oncologists should be judicious on the dose of radiation delivered to the lungs, the volume of lung irradiated, and concurrent use of chemotherapeutic drugs.

Barriers to Combined-Modality Therapy for Limited-Stage Small Cell Lung Cancer

Importance

Combined-modality therapy with chemotherapy and radiation therapy plays a crucial role in the upfront treatment of patients with limited-stage small cell lung cancer (SCLC), but there may be barriers to utilization in the United States.

Objective

To estimate utilization rates and factors associated with chemotherapy and radiation therapy delivery for limited-stage SCLC using the National Cancer Database.

Design, Setting, and Participants

Analysis of initial management of all limited-stage SCLC cases from 2004 through 2013 in the National Cancer Database.

Main Outcomes and Measures

Utilization rates of chemotherapy and radiation therapy at time of initial treatment. Multivariable analysis identified independent clinical and socioeconomic factors associated with utilization and overall survival.

Results

A total of 70 247 cases met inclusion criteria (55.3% female; median age, 68 y [range, 19-90 y]). Initial treatment was 55.5% chemotherapy and radiation therapy, 20.5% chemotherapy alone, 3.5% radiation therapy alone, and 20.0% neither (0.5% not reported). Median survival was 18.2 (95% CI, 17.9-18.4), 10.5 (95% CI, 10.3-10.7), 8.3 (95% CI, 7.7-8.8), and 3.7 (95% CI, 3.5-3.8) months, respectively. Being uninsured was associated with a lower likelihood of both chemotherapy (odds ratio [OR], 0.65; 95% CI, 0.56-0.75; P < .001) and radiation therapy (OR, 0.75; 95% CI, 0.67-0.85; P < .001) administration on multivariable analysis. Medicare/Medicaid insurance had no impact on chemotherapy use, whereas Medicaid (OR, 0.79; 95% CI, 0.72-0.87; P < .001) and Medicare (OR, 0.86; 95% CI, 0.82-0.91; P < .001) were independently associated with a lower likelihood of radiation therapy delivery. Lack of health insurance (HR, 1.19; 95% CI, 1.13-1.26; P < .001), Medicaid (HR, 1.27; 95% CI, 1.21-1.32; P < .001), and Medicare (HR, 1.12; 95% CI, 1.09-1.15; P < .001) coverage were independently associated with shorter survival on adjusted analysis, while chemotherapy (HR, 0.55; 95% CI, 0.54-0.57; P < .001) and radiation therapy (HR, 0.62; 95% CI, 0.60-0.63; P < .001) were associated with a survival benefit.

Conclusions and Relevance

Substantial proportions of patients documented in a major US cancer registry did not receive radiation therapy or chemotherapy as part of initial treatment for limited-stage SCLC, which, in turn, was associated with poor survival. Lack of radiation therapy delivery was uniquely associated with government insurance coverage, suggesting a need for targeted access improvement in this population. Additional work will be necessary to conclusively define exact population patterns, specific treatment deficiencies, and causative factors leading to heterogeneous care delivery.

Prophylactic Cranial Irradiation Following Surgical Resection of Early-Stage Small-Cell Lung Cancer: A Review of the Literature

With increasing use of low-dose screening CT scans, the diagnosis of early-stage small-cell lung cancer (SCLC) without evidence of mediastinal nodal or distant metastasis is likely to become more common, but the role of adjuvant therapies such as prophylactic cranial irradiation (PCI) are not well understood in this population. We performed a review of the literature pertaining to the impact of PCI in patients who underwent surgical resection of early-stage SCLC. Four studies were identified that were pertinent including three single-institution retrospective analyses and a National Cancer Database analysis. Based upon these studies, we estimate the rate of brain metastases to be 10-15% for Stage I and 15-25% for Stage II disease without PCI. However, the impact of PCI on the development of brain metastases and its ultimate impact on overall survival were not consistent across these studies. In summary, there is sparse evidence to guide recommendations for PCI following resection of early-stage SCLC. While it may be reasonable to offer PCI to maximize likelihood of cure, alternative strategies such as observation with close imaging follow-up can also be considered for the appropriate patient given the known neurocognitive side effects of PCI.

7-year follow-up after stereotactic ablative radiotherapy for patients with stage I non-small cell lung cancer: Results of a phase 2 clinical trial

BACKGROUND

The authors evaluated the efficacy, patterns of failure, and toxicity of stereotactic ablative radiotherapy (SABR) for patients with medically inoperable, clinical stage I non-small cell lung cancer (NSCLC) in a prospective clinical trial with 7 years of follow-up. Clinical staging was performed according to the seventh edition of the American Joint Committee on Cancer TNM staging system.

METHODS

Eligible patients with histologically confirmed NSCLC of clinical stage I as determined using positron emission tomography staging were treated with SABR (50 grays in 4 fractions). The primary endpoint was progression-free survival. Patients were followed with computed tomography and/or positron emission tomography/computed tomography every 3 months for the first 2 years, every 6 months for the next 3 years, and then annually thereafter.

RESULTS

A total of 65 patients were eligible for analysis. The median age of the patients was 71 years, and the median follow-up was 7.2 years. A total of 18 patients (27.7%) developed disease recurrence at a median of 14.5 months (range, 4.3-71.5 months) after SABR. Estimated incidences of local, regional, and distant disease recurrence using competing risk analysis were 8.1%, 10.9%, and 11.0%, respectively, at 5 years and 8.1%, 13.6%, and 13.8%, respectively, at 7 years. A second primary lung carcinoma developed in 12 patients (18.5%) at a median of 35 months (range, 5-67 months) after SABR. Estimated 5-year and 7-year progression-free survival rates were 49.5% and 38.2%, respectively; the corresponding overall survival rates were 55.7% and 47.5%, respectively. Three patients (4.6%) experienced grade 3 treatment-related adverse events. No patients developed grade 4 or 5 adverse events (toxicity was graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events [version 3.0]).

CONCLUSIONS

With long-term follow-up, the results of the current prospective study demonstrated outstanding local control and low toxicity after SABR in patients with clinical stage I NSCLC. Regional disease recurrence and distant metastases were the dominant manifestations of failure. Surveillance for second primary lung carcinoma is recommended. Cancer 2017;123:3031-39. © 2017 American Cancer Society.

Impact of Intensity-Modulated Radiation Therapy Technique for Locally Advanced Non-Small-Cell Lung Cancer: A Secondary Analysis of the NRG Oncology RTOG 0617 Randomized Clinical Trial

Purpose Although intensity-modulated radiation therapy (IMRT) is increasingly used to treat locally advanced non-small-cell lung cancer (NSCLC), IMRT and three-dimensional conformal external beam radiation therapy (3D-CRT) have not been compared prospectively. This study compares 3D-CRT and IMRT outcomes for locally advanced NSCLC in a large prospective clinical trial. Patients and Methods A secondary analysis was performed to compare IMRT with 3D-CRT in NRG Oncology clinical trial RTOG 0617, in which patients received concurrent chemotherapy of carboplatin and paclitaxel with or without cetuximab, and 60- versus 74-Gy radiation doses. Comparisons included 2-year overall survival (OS), progression-free survival, local failure, distant metastasis, and selected Common Terminology Criteria for Adverse Events (version 3) ≥ grade 3 toxicities. Results The median follow-up was 21.3 months. Of 482 patients, 53% were treated with 3D-CRT and 47% with IMRT. The IMRT group had larger planning treatment volumes (median, 427 v 486 mL; P = .005); a larger planning treatment volume/volume of lung ratio (median, 0.13 v 0.15; P = .013); and more stage IIIB disease (30.3% v 38.6%, P = .056). Two-year OS, progression-free survival, local failure, and distant metastasis-free survival were not different between IMRT and 3D-CRT. IMRT was associated with less ≥ grade 3 pneumonitis (7.9% v 3.5%, P = .039) and a reduced risk in adjusted analyses (odds ratio, 0.41; 95% CI, 0.171 to 0.986; P = .046). IMRT also produced lower heart doses ( P < .05), and the volume of heart receiving 40 Gy (V40) was significantly associated with OS on adjusted analysis ( P < .05). The lung V5 was not associated with any ≥ grade 3 toxicity, whereas the lung V20 was associated with increased ≥ grade 3 pneumonitis risk on multivariable analysis ( P = .026). Conclusion IMRT was associated with lower rates of severe pneumonitis and cardiac doses in NRG Oncology clinical trial RTOG 0617, which supports routine use of IMRT for locally advanced NSCLC.

Local Control and Toxicity of a Simultaneous Integrated Boost for Dose Escalation in Locally Advanced Esophageal Cancer: Interim Results from a Prospective Phase I/II Trial

INTRODUCTION

Approximately 50% of recurrences after standard-dose chemoradiation for locally advanced esophageal cancer occur within the gross tumor volume (GTV). In this prospective phase I/II clinical trial, we explored the use of a simultaneous integrated boost (SIB) dose to the GTV.

METHODS

Forty-four patients with unresectable esophageal cancer received chemoradiation with an SIB of 58.8 to 63 Gy to the GTV and 50.4 Gy to the planning target volume, all in 28 fractions, with 5 weeks of concurrent docetaxel and fluorouracil or capecitabine. The end points were maximum tolerated dose, time to local failure, and clinical response.

RESULTS

Excluding those with less than 6 months of follow-up, 38 patients were evaluated at the time of analysis. The median age was 65 years (range 37-84). Most patients (71%) were men; 84% had T3 disease, 37% had N1 disease, 26% had N2 disease, 13% had M1 disease, and 50% had adenocarcinoma. The maximum tolerated SIB dose was 63 Gy. None experienced Common Terminology Criteria for Adverse Events grade 4 or 5 toxicity. At a median follow-up time of 13.3 months (range 1.2-36.2), 11 (29%) had local failure (median time to local failure 2.5 months [range 1.5-23.9]). A comparison with 97 similar patients who received 50.4 Gy without an SIB showed that the SIB reduced the local failure rate for patients with node-positive disease (13% versus 56%, p = 0.04), adenocarcinoma (26% versus 59%, p = 0.02), or stage III-IV disease (29% versus 55%, p = 0.04).

CONCLUSIONS

SIB intensity-modulated radiation therapy to gross primary disease may improve local control for patients with unresectable locally advanced esophageal cancer, especially those with adenocarcinoma.

Final Results of NRG Oncology RTOG 0246: An Organ-Preserving Selective Resection Strategy in Esophageal Cancer Patients Treated with Definitive Chemoradiation

INTRODUCTION

The impact of selective surgical resection for patients with esophageal cancer treated with definitive chemoradiation has not been clearly evaluated long-term.

METHODS

NRG (National Surgical Adjuvant Breast and Bowel Project, Radiation Therapy Oncology Group, Gynecologic Oncology Group) Oncology Radiation Therapy Oncology Group 0246 was a multi-institutional, single-arm, open-label, nonrandomized phase II study that enrolled 43 patients from September 2003 to March 2008 with clinical stage T1-4N0-1M0 squamous cell or adenocarcinoma of the esophagus or gastroesophageal junction from 19 sites. Patients received induction chemotherapy with fluorouracil (650 mg/m²/d), cisplatin (15 mg/m²/d), and paclitaxel (200 mg/m²/d) for two cycles followed by concurrent chemoradiation consisting of 50.4 Gy of radiation (1.8 Gy per fraction) and daily fluorouracil (300 mg/m²/d) with cisplatin (15 mg/m²/d) over the first 5 days. After definitive chemoradiation, patients were evaluated for residual disease. Selective esophagectomy was considered only for patients with residual disease after chemoradiation (clinical incomplete response) or recurrent disease on surveillance.

RESULTS

This report looks at the long-term outcome of this selective surgical strategy. With a median follow-up of 8.1 years (minimum to maximum for 12 alive patients 7.2-9.8 years), the estimated 5- and 7-year survival rates are 36.6% (95% confidence interval [CI]: 22.3-51.0) and 31.7% (95% CI: 18.3-46.0). Clinical complete response was achieved in 15 patients (37%), with 5- and 7-yearr survival rates of 53.3% (95% CI: 26.3-74.4) and 46.7% (95% CI: 21.2-68.7). Esophageal resection was not required in 20 of 41 patients (49%) on this trial.

CONCLUSIONS

The long-term results of NRG Oncology Radiation Therapy Oncology Group 0246 demonstrate promising efficacy of a selective surgical resection strategy and suggest the need for larger randomized studies to further evaluate this organ-preserving approach.

Strategies for combining immunotherapy with radiation for anticancer therapy

Radiation therapy controls local disease but also prompts the release of tumor-associated antigens and stress-related danger signals that primes T cells to promote tumor regression at unirradiated sites known as the abscopal effect. This may be enhanced by blocking inhibitory immune signals that modulate immune activity through a variety of mechanisms. Indeed, abscopal responses have occurred in patients with lung cancer or melanoma when given anti-CTLA4 antibody and radiation. Other approaches involve expanding and reinfusing T or NK cells or engineered T cells to express receptors that target specific tumor peptides. These approaches may be useful for immunocompromised patients receiving radiation. Preclinical and clinical studies are testing both immune checkpoint-based strategies and adoptive immunotherapies with radiation.

Progress in the management of limited-stage small cell lung cancer

Approximately 15% of lung cancer cases are of the small cell subtype, but this variant is highly aggressive and is often diagnosed at advanced stages. Outcomes after current treatment regimens have been poor, with 5-year survival rates as low as 25% for patients with limited-stage disease. Advances in therapy for small cell lung cancer have included the development of more effective chemotherapeutic agents and radiation techniques. For example, hyperfractionated radiotherapy given early in the course of the disease can reduce local recurrence and extend survival. Other technologic advances in radiation planning and delivery such as intensity-modulated radiotherapy, image-guided adaptive radiotherapy, and 4-dimensional computed tomography/positron emission tomography have facilitated the design of treatment volumes that closely conform to the shape of the tumor, which allows higher radiation doses to be given while minimizing radiation-induced toxicity to adjacent structures. Future improvements in outcomes will require clarifying the molecular basis for this disease.

Abstract 1042: Maintenance or switch maintenance therapy with selumetinib or cediranib after chemoradiation prolongs survival in an orthotopic human lung cancer model

Background The outcome of lung cancer is poor and new therapies are needed. Selumetinib (AZD6244, ARRY-142886) and cediranib are potent MEK 1/2 and VEGFR tyrosine kinase inhibitors, respectively. In the current study, we evaluated the therapeutic efficacy of each with chemoradiation followed by maintenance therapy in a KRAS mutant orthotopic human non-small cell lung cancer model.

Methods NCI-H460 lung cancer cells were injected into the lungs of mice. Mice were randomized (32/group) to therapy with radiation (20 Gy in 5 fractions) + paclitaxel (200 μg/week), radiation, paclitaxel, and selumetinib (25 mg/kg/day) or cediranib (3 mg/kg/day), or vehicle control (n=8). When controls became moribund, 8 mice from each group were sacrificed and assessed for tumor burden. The remaining mice were re-randomized to switch or continuation maintenance with selumetinib or cediranib or vehicle (8/group). Mice were sacrificed when they became moribund and tumor tissues were subjected to immunohistologic analyses.

Results After the initiation phase, chemoradiation reduced tumor volume by 78% (p = 0.0002 vs control) with modest effects on regional metastases. The anti-tumor and anti-metastatic effects of chemoradiation were markedly enhanced by selumetinib or cediranib with a reduced total tumor volume of 96% and 99% (p = 0.002 or 0.0002) and primary lung tumor volume of 88% or 98% (p = 0.002 and 0.0002) compared to control. Trimodality therapy inhibited angiogenesis and tumor proliferation and increased tumor and endothelial cell apoptosis. In the maintenance phase, selumetinib or cediranib after chemoradiation prolonged survival compared to vehicle with a median survival of 41 or 43 vs 33 days (p = 0.008 or 0.005, respectively). Maintenance selumetinib or cediranib after chemoradiation + selumetinib resulted in a median survival of 46.5 or 53 vs 36.5 days for control (p = 0.001 or 0.0004, respectively). Maintenance selumetinib or cediranib after chemoradiation + cediranib improved survival by 52 or 67 vs 39 days for control (p = 0.0002). There was no significant survival difference for switch or continuation maintenance. The longest survival (105 days) was observed for selumetinib maintenance after chemoradiation + cediranib. Failure patterns with maintenance therapy included regional and distant metastases with brain, bone, and adrenal metastases observed.

Conclusions Selumetinib or cediranib substantially enhanced the effects of chemoradiation in an orthotopic human lung cancer model. Maintenance therapy with selumetinib or cediranib after trimodality therapy significantly prolonged survival. Mice developed regional and distant metastatic disease in patterns similar to those observed clinically. These data provide a basis for clinical trials and our model allows for the study of failure and resistance patterns with maintenance therapy in lung cancer.

Citation Format: Osamu Takahashi, Ritsuko U. Komaki, Juliane M. Jürgensmeier, Paul D. Smith, Ignacio I. Wistuba, Ramesh C. Tailor, Joerg J. Jacoby, Maria V. Korshunova, Yong Bae Kim, Baruch Erez, Roy S. Herbst, Michael S. O'Reilly. Maintenance or switch maintenance therapy with selumetinib or cediranib after chemoradiation prolongs survival in an orthotopic human lung cancer model. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1042. doi:10.1158/1538-7445.AM2013-1042

Modulation of c-Met signaling and cellular sensitivity to radiation: potential implications for therapy

The c-Met/hepatocyte growth factor receptor and its family members are known to promote cancer cell migration and invasion. Signaling within and beyond this pathway contributes to the systemic spread of metastases through induction of the epithelial-mesenchymal transition, a process also implicated in mediating resistance to current anticancer therapies, including radiation. Induction of c-Met has also been observed after irradiation, suggesting that c-Met participates in radiation-induced disease progression through the epithelial-mesenchymal transition. Therefore, c-Met inhibition is an attractive target for potentially mitigating radiation resistance. This article summarizes key findings regarding crosstalk between radiotherapy and c-Met and discusses studies performed to date in which c-Met inhibition was used as a strategy to increase cellular radiosensitivity.

Utilization of surgery in trimodality-eligible patients with locally advanced esophageal adenocarcinoma in a nonprotocol setting

Trimodality therapy with neoadjuvant chemoradiation followed by surgery significantly improves the survival of locally advanced (clinical stage IIA-III) esophageal cancer patients compared to treatment with surgery alone. This has resulted in an increased use of neoadjuvant therapy in recent years, yet little is known regarding how this increase has impacted the utilization of surgery in the treatment of locally advanced disease. Although previous reports of experimental protocols suggest that 90-95% of patients complete trimodality therapy including a surgical resection, trimodality therapy completion among adenocarcinoma patients eligible for curative resection has not been evaluated in a nonprotocol setting. We sought to (i) assess the completion of trimodality therapy among locally advanced esophageal adenocarcinoma patients; (ii) characterize the reasons for avoiding surgery; and (iii) identify factors associated with failure to complete trimodality therapy. We identified 296 patients with locally advanced esophageal adenocarcinoma eligible for trimodality therapy at our institution. All patients were evaluated in a multidisciplinary setting and considered eligible for curative resection after initial staging and physiologic assessment. Multivariable logistic regression was used to identify factors associated with failure to complete trimodality therapy. Of 296 trimodality-eligible patients, 33% (97/296) did not complete trimodality therapy. Reasons for not undergoing surgery included patient choice (27.8%, 27/97), distant progression of disease during chemoradiation (23.7%, 23/97), and physician preference for surveillance (23.7%, 23/97). In addition, 17.5% (17/97) of patients had physical deterioration in performance status, and treatment-related deaths occurred in 7.2% (7/97) prior to surgery. In the total study population (n = 296), multivariable logistic regression identified older age (≥70 years: odds ratio [OR] = 6.611, 95% confidence interval [CI]: 2.900-15.071), pretreatment standard uptake value (6.8-10.1: OR = 2.393, 95% CI: 1.050-5.455; ≥15.8: OR = 3.623, 95% CI: 1.604-8.186), and a radiation dose of 50.4 Gy (OR = 5.312, 95% CI: 2.365-11.929) as being significantly associated with failure to complete trimodality therapy. Among the subgroup of patients that successfully completed chemoradiation (n = 266), older patients (≥70 years: OR = 9.606, 95% CI: 3.637-25.372), those with a comorbidity score of 2 or higher (OR = 4.059, 95% CI: 1.257-13.103), and those that received a radiation dose of 50.4 Gy (OR = 4.878, 95% CI: 1.974-12.054) were at a significantly higher risk of not completing trimodality therapy. Trimodality therapy completion among patients with locally advanced esophageal adenocarcinoma in a nonprotocol setting is considerably lower than what has previously been reported in clinical trials. Our findings suggest that a selective approach to surgery is commonly utilized in clinical practice. Trimodality-eligible patients that are older and have a higher comorbidity score are at risk for not completing trimodality therapy.

Abstract 736: RTOG 0320:A phase III trial comparing whole brain radiation therapy (WBRT) and stereotactic radiosurgery (SRS) alone versus WBRT with temozolomide (TMZ) or erlotinib for non-small cell lung cancer (NSCLC) and 1-3 brain metastases

Background: A previous phase III RTOG study subset analysis demonstrated improvement in overall survival (OS) with the addition of SRS to WBRT in NSCLC patients with 1 to 3 brain metastases. As both TMZ and erlotinib are known to cross the blood brain barrier (potentially providing radiosensitization), and have documented activity in NSCLC, a phase III study was designed to test whether either of these drugs would improve outcome of WBRT/SRS. Methods: NSCLC patients (n=126) with 1-3 brain metastases were randomized (10/2005 to 8/2009; study closed prematurely due to slow accrual) to receive WBRT (2.5 Gy x 15 to 37.5Gy) + SRS alone, vs. WBRT/SRS with TMZ (75mg/m2/D x 21) or erlotinib (150mg/D). Erlotinib or TMZ (150-200 mg/m2/D x 5/mo) could be given in the drug arms post-WBRT/SRS at the discretion of the investigator. The primary endpoint was overall survival (OS). Results: Arms were stratified by RTOG recursive partitioning analysis (RPA) class and balanced for prognostic variables including the Graded Prognostic Assessment (GPA) score. Neither the addition of erlotinib nor TMZ to WBRT/SRS resulted in an improvement in OS, or time to CNS progression compared to WBRT/SRS alone. Patients in the WBRT/SRS arm had longer MST (Median Survival Time) (13.4 mo, 95% CI = 6.5-20.8 mo.) compared to the WBRT+SRS+ erlotinib (6.1 mo, 95% CI = 3.6-12.1 mo)[Hazard ratio (≥2 / α1) and 95% CI; 1.47 (0.92 to 2.36)], or TMZ (6.3 mo, 95% CI= 3.4-10.1 mo.) [Hazard ratio (β3 / α1) and 95% CI; 1.43 (0.89 to 2.31)]. This surprising result was not related to excess toxicity. In fact, patients experiencing grade 3+ Adverse Events (AE) appear to have longer OS than those patients without grade 3+ AE for both drug arms. The WBRT/SRS arm had significantly less deterioration in performance status at 6 mo. There were no significant differences between arms for steroid dependence at 6 mo, or causes of death. Conclusion: The addition of either TMZ or erlotinib to WBRT/SRS in this unselected population of NSCLC patients with 1-3 brain metastases provided no clinical advantage. Treatment with WBRT/SRS alone appeared to result in superior outcome data (compared to the addition of TMZ or erlotinib) relative to OS in this limited data set. Detailed analysis to date provides no obvious explanation for these unexpected results. Support: RTOG grant U10 CA21661, and CCOP grant U10 CA37422 from the National Cancer Institute (NCI)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 736. doi:1538-7445.AM2012-736

A Phase II study of a paclitaxel-based chemoradiation regimen with selective surgical salvage for resectable locoregionally advanced esophageal cancer: initial reporting of RTOG 0246

PURPOSE

The strategy of definitive chemoradiation with selective surgical salvage in locoregionally advanced esophageal cancer was evaluated in a Phase II trial in Radiation Therapy Oncology Group (RTOG)-affiliated sites.

METHODS AND MATERIALS

The study was designed to detect an improvement in 1-year survival from 60% to 77.5% (α = 0.05; power = 80%). Definitive chemoradiation involved induction chemotherapy with 5-fluorouracil (5-FU) (650 mg/mg(2)/day), cisplatin (15 mg/mg(2)/day), and paclitaxel (200 mg/mg(2)/day) for two cycles, followed by concurrent chemoradiation with 50.4 Gy (1.8 Gy/fraction) and daily 5-FU (300 mg/mg(2)/day) with cisplatin (15 mg/mg(2)/day) over the first 5 days. Salvage surgical resection was considered for patients with residual or recurrent esophageal cancer who did not have systemic disease.

RESULTS

Forty-three patients with nonmetastatic resectable esophageal cancer were entered from Sept 2003 to March 2006. Forty-one patients were eligible for analysis. Clinical stage was ≥T3 in 31 patients (76%) and N1 in 29 patients (71%), with adenocarcinoma histology in 30 patients (73%). Thirty-seven patients (90%) completed induction chemotherapy followed by concurrent chemoradiation. Twenty-eight patients (68%) experienced Grade 3+ nonhematologic toxicity. Four treatment-related deaths were noted. Twenty-one patients underwent surgery following definitive chemoradiation because of residual (17 patients) or recurrent (3 patients) esophageal cancer,and 1 patient because of choice. Median follow-up of live patients was 22 months, with an estimated 1-year survival of 71%.

CONCLUSIONS

In this Phase II trial (RTOG 0246) evaluating selective surgical salvage after definitive chemoradiation in locoregionally advanced esophageal cancer, the hypothesized 1-year RTOG survival rate (77.5%) was not achieved (1 year, 71%; 95% confidence interval< 54%-82%).

Abstract 2658: Phase II study of chemoradiation therapy and erlotinib for stage III non-small cell lung cancer

Preclinical evidence that the epidermal growth factor receptor (EGFR) inhibitor erlotinib has radiosensitizing properties in vitro led us to test its use, in combination with standard chemoradiation therapy (ChRT), in a prospective phase II study of patients with locally advanced non-small cell lung cancer. Endpoints were radiographic response, survival rates, and toxicity. We also tested if EGFR copy number or protein expression and mutations in EGFR exons 19-21 or KRAS codons 12-13, all measured in formalin-fixed paraffin-embedded biopsy specimens, predicted response to this therapy. Patients were to receive ChRT (RT=63 Gy in 35 fractions in 7 wks; Ch=weekly paclitaxel 45 mg/m2+carboplatin AUC 2) with erlotinib 150 mg po daily (except on Ch days) followed by two cycles of consolidation Ch. Of the 48 patients enrolled (30 male, 18 female; median age 64 yr; all with good performance status), 38 were evaluable for response. At a median follow-up of 11 months, the response rate was 79% (29% complete and 50% partial); 10% had stable disease and 11% progressive disease. The overall survival rate at 1 yr was 85%; 42% were alive without evidence of disease, 34% alive with disease, and 24% dead. Severe acute toxicity (grade 3 in the NCI Common Terminology Criteria v3) was manageable and included pneumonia (n=7), skin reactions (n=4), pneumonitis (n=3), and dehydration (n=3); several hematologic toxicity included leukopenia (n=13), neutropenia (n=7), and thrombocytopenia (n=1). No patients died of treatment-related causes. Of the 34 patients with biopsy specimens, only 3 showed EGFR mutation and 1 a KRAS mutation, and none correlated with response. However, complete response was more likely among current or former smokers (n=10) than never-smokers (n=0, P=0.023). We conclude that the 1-yr overall survival rate was promising but the complete response rate was disappointing. Erlotinib may have had a radiosensitizing effect in vivo, but additional patients and longer follow-up are needed.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2658. doi:10.1158/1538-7445.AM2011-2658

Consideration of dose limits for organs at risk of thoracic radiotherapy: atlas for lung, proximal bronchial tree, esophagus, spinal cord, ribs, and brachial plexus

PURPOSE

To review the dose limits and standardize the three-dimenional (3D) radiographic definition for the organs at risk (OARs) for thoracic radiotherapy (RT), including the lung, proximal bronchial tree, esophagus, spinal cord, ribs, and brachial plexus.

METHODS AND MATERIALS

The present study was performed by representatives from the Radiation Therapy Oncology Group, European Organization for Research and Treatment of Cancer, and Soutwestern Oncology Group lung cancer committees. The dosimetric constraints of major multicenter trials of 3D-conformal RT and stereotactic body RT were reviewed and the challenges of 3D delineation of these OARs described. Using knowledge of the human anatomy and 3D radiographic correlation, draft atlases were generated by a radiation oncologist, medical physicist, dosimetrist, and radiologist from the United States and reviewed by a radiation oncologist and medical physicist from Europe. The atlases were then critically reviewed, discussed, and edited by another 10 radiation oncologists.

RESULTS

Three-dimensional descriptions of the lung, proximal bronchial tree, esophagus, spinal cord, ribs, and brachial plexus are presented. Two computed tomography atlases were developed: one for the middle and lower thoracic OARs (except for the heart) and one focusing on the brachial plexus for a patient positioned supine with their arms up for thoracic RT. The dosimetric limits of the key OARs are discussed.

CONCLUSIONS

We believe these atlases will allow us to define OARs with less variation and generate dosimetric data in a more consistent manner. This could help us study the effect of radiation on these OARs and guide high-quality clinical trials and individualized practice in 3D-conformal RT and stereotactic body RT.

Accelerated fractionation radiation therapy for liver metastases: selection of an optimal patient population for the evaluation of late hepatic injury in RTOG studies

The palliation of hepatic metastases represents a major therapeutic problem in oncology. The generally unfavorable prognosis of patients with liver metastasis may complicate the evaluation of the efficacy and toxicity of various therapeutic modalities. The Radiation Therapy Oncology Group (RTOG) is evaluating new accelerated fractionation schemes for hepatic irradiation. In designing this study it became necessary to identify a favorable subpopulation of patients with an expected median survival of 6 months in whom the late effects of treatment could be evaluated. Data from two RTOG liver metastases studies (7605 and 8003) were analyzed using multi-variate techniques. Cases with a serum bilirubin level of greater than 1.5 mg%, performance score of less than 50, and gastric or pancreatic primary carcinomas were initially excluded because of the adverse influence of these factors on survival. One hundred and ninety cases met the criteria for inclusion in this analysis. A loglinear model was used to identify the patient characteristics associated with a favorable prognosis for survival. These included a performance score of 80-100, colorectal carcinoma primary, and no extrahepatic metastases. A logistic regression equation was derived and confirmed that the probability of surviving at least 6 months depended on the effects of performance score, primary site and the presence or absence of extra-hepatic metastases. Patients with all three favorable factors constituted 30% of the evaluable study population and had a predicted survival of 50% at 6 months. A patient population with these characteristics will be used to study the late effects of accelerated fractionated radiation therapy on the liver.

A comparison of misonidazole sensitized radiation therapy to radiation therapy alone for the palliation of hepatic metastases: results of a Radiation Therapy Oncology Group randomized prospective trial

Between May 1980 and July 1983, the RTOG conducted a randomized prospective study comparing external radiation therapy and misonidazole to radiation therapy alone for patients with hepatic metastases. Two hundred fourteen patients were accessioned to this study of whom 187 were evaluable. Radiation therapy was delivered to the whole liver to a dose of 21.0 Gy in 7 fractions. Misonidazole was administered orally, 1.5 gm/m2 daily 4-6 hr before each treatment. Patients in the two treatment groups were evenly distributed with respect to stratification variables including primary site, extent of metastatic disease, and Karnofsky Performance Score (KPS). End points examined included amelioration of hepatic pain, improvement of KPS and alkaline phosphatase, decrease in liver and tumor size, and survival. The addition of misonidazole did not significantly improve the therapeutic response to radiation therapy in any of the parameters studied. Hepatic irradiation was effective in relieving abdominal pain with 80% of the symptomatic patients achieving improvement following therapy. Pain was completely relieved in 54% of these patients. Patients with liver metastases from colon carcinoma improved more frequently than those with metastases from other primary tumor sites (p = 0.02). Relief of pain occurred more frequently in patients treated with radiation therapy and misonidazole (87%) compared with radiation therapy alone (74%) (p = 0.08). Palliation of pain was prompt, occurring within a median of 1.7 weeks from the initiation of treatment, and 94% of patients who improved did so within 6 weeks of treatment. The median duration of response was 13.0 weeks in the symptomatic patients; 52% of those surviving 3 months remained improved. KPS improved in 28% of patients. Serial CT scans revealed a partial response in 7% and a marginal response in 13% of patients. One patient had a complete response to treatment. The median survival of patients treated in this series was 4.2 months with no difference between the two treatment groups. Patients with metastases from colon carcinoma and an initial KPS of 80 or more (48% of the patient population) had a median survival of 5.8 months with radiation therapy alone compared with 6.6 months with radiation therapy and misonidazole (p = 0.36). There was no significant treatment related morbidity. Radiation therapy remains an excellent palliative tool for the management of patients with symptomatic hepatic metastases. Further research must continue to identify new methods of selectivity enhancing the tumor response to radiation therapy.