Modeling the risk of radiation-induced acute esophagitis for combined Washington University and RTOG trial 93-11 lung cancer patients.

PURPOSE: To construct a maximally predictive model of the risk of severe acute esophagitis (AE) for patients who receive definitive radiation therapy (RT) for non-small-cell lung cancer. METHODS AND MATERIALS: The dataset includes Washington University and RTOG 93-11 clinical trial data (events/patients: 120/374, WUSTL = 101/237, RTOG9311 = 19/137). Statistical model building was performed based on dosimetric and clinical parameters (patient age, sex, weight loss, pretreatment chemotherapy, concurrent chemotherapy, fraction size). A wide range of dose-volume parameters were extracted from dearchived treatment plans, including Dx, Vx, MOHx (mean of hottest x% volume), MOCx (mean of coldest x% volume), and gEUD (generalized equivalent uniform dose) values. RESULTS: The most significant single parameters for predicting acute esophagitis (RTOG Grade 2 or greater) were MOH85, mean esophagus dose (MED), and V30. A superior-inferior weighted dose-center position was derived but not found to be significant. Fraction size was found to be significant on univariate logistic analysis (Spearman R = 0.421, p < 0.00001) but not multivariate logistic modeling. Cross-validation model building was used to determine that an optimal model size needed only two parameters (MOH85 and concurrent chemotherapy, robustly selected on bootstrap model-rebuilding). Mean esophagus dose (MED) is preferred instead of MOH85, as it gives nearly the same statistical performance and is easier to compute. AE risk is given as a logistic function of (0.0688 MED+1.50 ConChemo-3.13), where MED is in Gy and ConChemo is either 1 (yes) if concurrent chemotherapy was given, or 0 (no). This model correlates to the observed risk of AE with a Spearman coefficient of 0.629 (p < 0.000001). CONCLUSIONS: Multivariate statistical model building with cross-validation suggests that a two-variable logistic model based on mean dose and the use of concurrent chemotherapy robustly predicts acute esophagitis risk in combined-data WUSTL and RTOG 93-11 trial datasets.

A phase I/II radiation dose escalation study with concurrent chemotherapy for patients with inoperable stages I to III non-small-cell lung cancer: phase I results of RTOG 0117.

PURPOSE: In preparation for a Phase III comparison of high-dose versus standard-dose radiation therapy, this Phase I/II study was initiated to establish the maximum tolerated dose of radiation therapy in the setting of concurrent chemotherapy, using three-dimensional conformal radiation therapy for non-small-cell lung cancer. METHODS AND MATERIALS: Eligibility included patients with histologically proven, unresectable Stages I to III non-small-cell lung cancer. Concurrent chemotherapy consisted of paclitaxel, 50 mg/m(2), and carboplatin, AUC of 2, given weekly. The radiation dose was to be sequentially intensified by increasing the daily fraction size, starting from 75.25 Gy/35 fractions. RESULTS: The Phase I portion of this study accrued 17 patients from 10 institutions and was closed in January 2004. After the initial 8 patients were accrued to cohort 1, the trial closed temporarily on September 26, 2002, due to reported toxicity. Two acute treatment-related dose-limiting toxicities (DLTs) were reported at the time: a case of grade 5 and grade 3 radiation pneumonitis. The protocol, therefore, was revised to de-escalate the radiation therapy dose (74 Gy/37 fractions). Patients in cohort 1 continued to develop toxicity, with 6/8 (75%) patients eventually developing grade >or=3 events. Cohort 2 accrued 9 patients. There was one DLT, a grade 3 esophagitis, in cohort 2 in the first 5 patients (1/5 patients) and no DLTs for the next 2 patients (0/2 patients). CONCLUSIONS: The maximum tolerated dose was determined to be 74 Gy/37 fractions (2.0 Gy per fraction) using three-dimensional conformal radiation therapy with concurrent paclitaxel and carboplatin therapy. This dose level in the Phase II portion has been well tolerated, with low rates of acute and late lung toxicities.

Primary analysis of the phase II component of a phase I/II dose intensification study using three-dimensional conformal radiation therapy and concurrent chemotherapy for patients with inoperable non-small-cell lung cancer: RTOG 0117.

PURPOSE: Phase I of Radiation Therapy Oncology Group (RTOG) 0117 determined that 74 Gy was the maximum-tolerated dose with concurrent weekly carboplatin/paclitaxel chemotherapy for inoperable non-small-cell lung cancer (NSCLC). Phase II results are reported here. PATIENTS AND METHODS Patients with unresectable stages I-III NSCLC were eligible. Chemotherapy consisted of weekly paclitaxel at 50 mg/m(2) and carboplatin at area under the curve 2 mg/m(2). The radiation dose was 74 Gy given in 37 fractions. Radiation therapy volumes included those of the gross tumor and involved nodes. The volume of lung at or exceeding 20 Gy (V20) was mandated to be or= 3 lung toxicity (two patients had grade 5 lung toxicity). CONCLUSION: The median survival time and OS rate at 12 months for this regimen are encouraging. These results serve as projection expectations for the high-dose radiation arms of the current RTOG 0617 phase III intergroup trial.

A nomogram to predict radiation pneumonitis, derived from a combined analysis of RTOG 9311 and institutional data.

PURPOSE: To test the Washington University (WU) patient dataset, analysis of which suggested that superior-to-inferior tumor position, maximum dose, and D35 (minimum dose to the hottest 35% of the lung volume) were valuable to predict radiation pneumonitis (RP), against the patient database from Radiation Therapy Oncology Group (RTOG) trial 9311. METHODS AND MATERIALS: The entire dataset consisted of 324 patients receiving definitive conformal radiotherapy for non-small-cell lung cancer (WU = 219, RTOG 9311 = 129). Clinical, dosimetric, and tumor location parameters were modeled to predict RP in the individual datasets and in a combined dataset. Association quality with RP was assessed using Spearman's rank correlation (r) for univariate analysis and multivariate analysis; comparison between subgroups was tested using the Wilcoxon rank sum test. RESULTS: The WU model to predict RP performed poorly for the RTOG 9311 data. The most predictive model in the RTOG 9311 dataset was a single-parameter model, D15 (r = 0.28). Combining the datasets, the best derived model was a two-parameter model consisting of mean lung dose and superior-to-inferior gross tumor volume position (r = 0.303). An equation and nomogram to predict the probability of RP was derived using the combined patient population. CONCLUSIONS: Statistical models derived from a large pool of candidate models resulted in well-tuned models for each subset (WU or RTOG 9311), which did not perform well when applied to the other dataset. However, when the data were combined, a model was generated that performed well on each data subset. The final model incorporates two effects: greater risk due to inferior lung irradiation, and greater risk for increasing normal lung mean dose. This formula and nomogram may aid clinicians during radiation treatment planning for lung cancer.

Phase II trial of postoperative adjuvant paclitaxel/carboplatin and thoracic radiotherapy in resected stage II and IIIA non-small-cell lung cancer: promising long-term results of the Radiation Therapy Oncology Group--RTOG 9705.

PURPOSE: To determine the overall survival, progression-free survival, and toxicity associated with concurrent paclitaxel/carboplatin and thoracic radiotherapy for completely resected patients with stage II and IIIA non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Eighty-eight eligible patients had surgical resection for pathologic stage II or IIIA disease and received postoperative paclitaxel and carboplatin. Concurrent thoracic radiotherapy at 50.4 Gy in 28 fractions for 6 weeks (1.8 Gy/d, 5 days/wk) was given during cycles 1 and 2. A boost of 10.8 Gy in six fractions was given for extracapsular nodal extension or T3 lesions. RESULTS: Treatment compliance was acceptable, with 93% compliance for radiation therapy and 86% for chemotherapy completion. The median duration of follow-up was 56.7 months (range, 17 to 61 months). The median overall survival time was 56.3 months, with 1-, 2-, and 3-year survival rates of 86%, 70%, and 61%, respectively. The 1-, 2-, and 3- year progression-free survival rates were 70%, 57%, and 50%, respectively. Brain metastasis occurred as the sole site of first failure in 11%, and 9% failed in other metastatic sites as first failure. Of the 43 patients who died, the cause of death was the treated cancer in 31 (35%). Local failure was a component of first failure in 15% of patients. Toxicities were acceptable. An overall survival comparison to Eastern Cooperative Oncology Group 3590 is favorable. CONCLUSION: The mature results of this trial suggest an improved overall and progression-free survival in this group of resected NSCLC patients, compared with previously reported trials. A phase III trial comparing this treatment regimen with standard therapy seems warranted.

Toxicity and outcome results of RTOG 9311: a phase I-II dose-escalation study using three-dimensional conformal radiotherapy in patients with inoperable non-small-cell lung carcinoma.

PURPOSE: To evaluate prospectively the acute and late morbidities from a multiinstitutional three-dimensional radiotherapy dose-escalation study for inoperable non-small-cell lung cancer. METHODS AND MATERIALS: A total of 179 patients were enrolled in a Phase I-II three-dimensional radiotherapy dose-escalation trial. Of the 179 patients, 177 were eligible. The use of concurrent chemotherapy was not allowed. Twenty-five patients received neoadjuvant chemotherapy. Patients were stratified at escalating radiation dose levels depending on the percentage of the total lung volume that received >20 Gy with the treatment plan (V(20)). Patients with a V(20) <25% (Group 1) received 70.9 Gy in 33 fractions, 77.4 Gy in 36 fractions, 83.8 Gy in 39 fractions, and 90.3 Gy in 42 fractions, successively. Patients with a V(20) of 25-36% (Group 2) received doses of 70.9 Gy and 77.4 Gy, successively. The treatment arm for patients with a V(20) > or =37% (Group 3) closed early secondary to poor accrual (2 patients) and the perception of excessive risk for the development of pneumonitis. Toxicities occurring or persisting beyond 90 days after the start of radiotherapy were scored as late toxicities. The estimated toxicity rates were calculated on the basis of the cumulative incidence method. RESULTS: The following acute Grade 3 or worse toxicities were observed for Group 1: 70.9 Gy (1 case of weight loss), 77.4 Gy (nausea and hematologic toxicity in 1 case each), 83.8 Gy (1 case of hematologic toxicity), and 90.3 Gy (3 cases of lung toxicity). The following acute Grade 3 or worse toxicities were observed for Group 2: none at 70.9 Gy and 2 cases of lung toxicity at 77.4 Gy. No patients developed acute Grade 3 or worse esophageal toxicity. The estimated rate of Grade 3 or worse late lung toxicity at 18 months was 7%, 16%, 0%, and 13% for Group 1 patients receiving 70.9, 77.4, 83.8, or 90.3 Gy, respectively. Group 2 patients had an estimated late lung toxicity rate of 15% at 18 months for both 70.9 and 77.4 Gy. The prognostic factors for late pneumonitis in multivariate analysis were the mean lung dose and V(20). The estimated rate of late Grade 3 or worse esophageal toxicity at 18 months was 8%, 0%, 4%, and 6%, for Group 1 patients receiving 70.9, 77.4, 83.8, 90.3 Gy, respectively, and 0% and 5%, respectively, for Group 2 patients receiving 70.9 and 77.4 Gy. The dyspnea index scoring at baseline and after therapy for functional impairment, magnitude of task, and magnitude of effort revealed no change in 63%, functional pulmonary loss in 23%, and pulmonary improvement in 14% of patients. The observed locoregional control and overall survival rates were each similar among the study arms within each dose level of Groups 1 and 2. Locoregional control was achieved in 50-78% of patients. Thirty-one patients developed regional nodal failure. The location of nodal failure in relationship to the RT volume was documented in 28 of these 31 patients. Twelve patients had isolated elective nodal failures. Fourteen patients had regional failure in irradiated nodal volumes. Two patients had both elective nodal and irradiated nodal failure. CONCLUSIONS: The radiation dose was safely escalated using three-dimensional conformal techniques to 83.8 Gy for patients with V(20) values of <25% (Group 1) and to 77.4 Gy for patients with V(20) values between 25% and 36% (Group 2), using fraction sizes of 2.15 Gy. The 90.3-Gy dose level was too toxic, resulting in dose-related deaths in 2 patients. Elective nodal failure occurred in <10% of patients.

The impact of regional nodal radiotherapy (dose/volume) on regional progression and survival in unresectable non-small cell lung cancer: an analysis of RTOG data.

PURPOSE: To evaluate in-field progression and survival of patients with unresectable non-small cell lung cancer (NSCLC) in relation to adequacy of coverage of thoracic regional nodal areas in the radiotherapy volume. MATERIALS AND METHODS: A total of 1705 patients from four large RTOG trials (78-11, 79-17, 83-11 and 84-07) were analyzed for this purpose. For each of these trials, the dose delivered to nodal regions was recorded and an assessment of adequacy of field borders was made. Each nodal site was assessed for progression, defined as in-field or out-of-field. In patients who had adequate borders on nodal regions, the results were analyzed according to the dose delivered. RESULTS: The majority (74%) of patients were between the age of 55-75. Forty-six percent of the patients had KPS of 60-80 and 52% had KPS of 90-100. Sixty percent of patients had a weight loss of less than 5% in the 6 months prior to diagnosis. Deviations from the protocol in field borders (borders not per protocol) were most frequent for the contralateral hilum (25.2%) and least frequent in the ipsilateral hilum (6.3%). The adequacy of ipsilateral hilar coverage was important for preventing the in-field progression (11.6 vs. 22% for adequately vs. inadequately covered ipsilateral hilum, respectively, P=0.01), however, did not influence the 2-year-survival (35 vs. 37%) or median survival (1.3 vs. 1.1 year). Neither the in-field progression nor the 2-year-survival were affected by adequacy of nodal coverage in the mediastinum, ipsilateral supraclavicular area and contralateral hilum, even when different doses were analyzed. CONCLUSION: These data suggest that elective irradiation of mediastinal, contralateral hilar and supraclavicular lymph nodes may not be necessary in the treatment of unresectable NSCLC.

Gross tumor volume, critical prognostic factor in patients treated with three-dimensional conformal radiation therapy for non-small-cell lung carcinoma.

PURPOSE: Three-dimensional conformal radiation therapy (3D-CRT) has recently become widely available with applications for patients with non-small-cell lung cancer (NSCLC). These techniques represent a significant advance in the delivery of radiotherapy, including improved ability to delineate target contours, choose beam angles, and determine dose distributions more accurately than were previously available. The purpose of this study is to identify prognostic factors in a population of NSCLC patients treated with definitive 3D-CRT. METHODS AND MATERIALS: Between March 1991 and December 1998, 207 patients with inoperable NSCLC were treated with definitive 3D-CRT. Tumor targets were contoured in multiple sections from a treatment planning computed tomography (CT) scan. Three-dimensional treatment volumes and normal structures were reconstructed. Doses to the International Commission on Radiation Units and Measurements (ICRU) reference point ranged from 60 to 83.85 Gy with a median dose of 70 Gy. The median dose inhomogeneity was +/- 5% across planning target volume. Outcome was analyzed by prognostic factors for NSCLC including pretreatment patient and tumor-related factors (age, gender, race, histology, clinical stage, tumor [T] stage, and node [N] stage), parameters from our 3D-CRT system (gross tumor volume [GTV] in cm3), irradiation dose prescribed to isocenter, volume of normal lung exceeding 20 Gy (V20), and treatment with or without chemotherapy. The median follow-up time was 24 months (range, 7.5 months to 7.5 years). RESULTS: One and two-year overall survival rates for the entire group were 59% and 41%, respectively. Overall survival, cause-specific survival, and local tumor control were most highly correlated with the GTV in cm3. On multivariate analysis the independent variable most predictive of survival was the GTV. Traditional staging such as T, N, and overall clinical staging were not independent prognostic factors. Patients receiving ICRU reference doses > or =70 Gy had better local control and cause-specific survivals than those treated with lower doses (p = 0.05). Increased irradiation dose did not improve overall survival. CONCLUSIONS: GTV as determined by CT and 3D-CRT planning is highly prognostic for overall and cause-specific survival and local tumor control and may be important in stratification of patients in prospective therapy trials. T, N, and overall stage were not independent prognostic factors in this population of patients treated nonsurgically. The value of dose escalation beyond 70 Gy should be tested prospectively by clinical trial.