Hyperfractionated accelerated radiation therapy for non-small cell lung cancer: clinical phase I/II trial

Accelerated hypofractionated radiotherapy for advanced lung cancer

Introduction – purpose

The aim of this study is to review the results of applying a hypofractionated radiotherapy schedule for locally advanced inoperable lung cancer in patients who have received chemotherapy. Lung cancer and especially non-small-cell lung cancer is prone to accelerated repopulation and shorter treatment schedules in the form of accelerated radiotherapy have been shown to improve treatment outcome.

Patients – method

In total, 29 patients with inoperable lung cancer (stage II, IIIa,b, IV) were treated with accelerated hypofractionated 3D conformal radiotherapy. All patients received a dose of 55 Gy in 20 fractions (daily dose of 2·75 Gy). The median age was 65·5 years, 87% of patients had stage III–IV disease, 93% of patients received sequential chemotherapy with their radiotherapy. Median follow-up of patients was 36 months.

Results

The median overall survival from time of diagnosis was 16·5 months and the 1 year overall survival was 31%. Complications were present in 44·8% of the patients and the most common complication (20·7%) was pneumonitis alone. The complication rate was not significantly different according to histological type, stage, type of chemotherapy, presence of recurrence or death.

Conclusion

Although our study limitation is the small number of patients, these data suggest that the efficacy of this hypofractionated schedule could be considered as alternative option to the conventional regimen of 66 Gy given in 33 fractions.

Analysis of predictive parameters for the development of radiation-induced pneumonitis

INTRODUCTION:

Prevention and effective treatment of radiation-induced pneumonitis (RP) could facilitate greater use of radiation therapy (RT) for lung cancer. The purpose of this study was to determine clinical parameters useful for early prediction of RP.

METHODS:

Blood sampling, pulmonary function testing, chest computed tomography, and bronchoalveolar lavage (BAL) were performed in patients with pathologically confirmed lung cancer who had completed ≥60 Gy of RT, at baseline, shortly after RT, and at 1 month posttreatment.

RESULTS:

By 3 months post-RT, 11 patients developed RP (RP group) and the remaining 11 patients did not (NRP group). RT significantly increased total cell counts and alveolar macrophages in BAL of the NRP group, whereas lymphocyte count was increased in both groups. Matrix metallopeptidase-9 (MMP-9) increased and vascular endothelial growth factor decreased significantly in the BAL fluid (BALF) of the RP group following RT. Serum surfactant protein D (SP-D) increased significantly in the NRP group. SP-D in BALF from the RP group increased significantly with a subsequent increase in serum SP-D. Pulmonary dilution decreased similarly in both groups of patients.

CONCLUSIONS:

Increased SP-D in BALF, rather than that in serum, could be useful biomarkers in predicting RP. The MMP-9 in BALF might play a role in the pathogenesis of RP. Pulmonary dilution test may not be predictive of the development of RP.

Hyperfractionated and accelerated radiotherapy in non-small cell lung cancer

Radical radiotherapy plays a major role in the treatment of non-small cell lung cancer (NSCLC) due to the fact that many patients are medically or surgically inoperable. Advances in technology and radiotherapy delivery allow targeted treatment of the disease, whilst minimizing the dose to organs at risk. This in turn creates an opportunity for dose escalation and the prospect of tailoring radiotherapy treatment to each patient. This is especially important in patients deemed unsuitable for chemotherapy or surgery, where there is a need to increase the therapeutic gain from radical radiotherapy alone. Recent research into fractionation schedules, with hyperfractionated and accelerated radiotherapy regimes has been promising. How to combine these new fractionated schedules with dose escalation and chemotherapy remains open to debate and there is local, national and international variation in management with a lack of overall consensus. An overview of the current literature on hyperfractionated and accelerated radiotherapy in NSCLC is provided.

Altered fractionation in radiotherapy: from radiobiological rationale to therapeutic gain

The implementation of altered fractionation schedules in clinical practice came as a need to improve loco-regional control and survival in those cancer patient groups which did not respond satisfactorily to conventionally fractionated radiotherapy. The current review aims to present the radiobiological rationale behind various non-conventional treatment schedules including the encountered challenges, through a compilation of clinical studies/trials and their contribution towards therapeutic gain.

A neural network model to predict lung radiation-induced pneumonitis

A feed-forward neural network was investigated to predict the occurrence of lung radiation-induced Grade 2+ pneumonitis. The database consisted of 235 patients with lung cancer treated using radiotherapy, of whom 34 were diagnosed with Grade 2+ pneumonitis at follow-up. The network was constructed using an algorithm that alternately grew and pruned it, starting from the smallest possible network, until a satisfactory solution was found. The weights and biases of the network were computed using the error back-propagation approach. Momentum and variable leaning techniques were used to speed convergence. Using the growing/pruning approach, the network selected features from 66 dose and 27 non-dose variables. During network training, the 235 patients were randomly split into ten groups of approximately equal size. Eight groups were used to train the network, one group was used for early stopping training to prevent overfitting, and the remaining group was used as a test to measure the generalization capability of the network (cross-validation). Using this methodology, each of the ten groups was considered, in turn, as the test group (ten-fold cross-validation). For the optimized network constructed with input features selected from dose and non-dose variables, the area under the receiver operating characteristics (ROC) curve for cross-validated testing was 0.76 (sensitivity: 0.68, specificity: 0.69). For the optimized network constructed with input features selected only from dose variables, the area under the ROC curve for cross-validation was 0.67 (sensitivity: 0.53, specificity: 0.69). The difference between these two areas was statistically significant (p = 0.020), indicating that the addition of non-dose features can significantly improve the generalization capability of the network. A network for prospective testing was constructed with input features selected from dose and non-dose variables (all data were used for training). The optimized network architecture consisted of six input nodes (features), four hidden nodes, and one output node. The six input features were: lung volume receiving > 16 Gy (V16), generalized equivalent uniform dose (gEUD) for the exponent a = 1 (mean lung dose), gEUD for the exponent a = 3.5, free expiratory volume in 1 s (FEV1), diffusion capacity of carbon monoxide (DLCO%), and whether or not the patient underwent chemotherapy prior to radiotherapy. The significance of each input feature was individually evaluated by omitting it during network training and gauging its impact by the consequent deterioration in cross-validated ROC area. With the exception of FEV1 and whether or not the patient underwent chemotherapy prior to radiotherapy, all input features were found to be individually significant (p < 0.05). The network for prospective testing is publicly available via internet access.

Predicting lung radiotherapy-induced pneumonitis using a model combining parametric Lyman probit with nonparametric decision trees

PURPOSE

To develop and test a model to predict for lung radiation-induced Grade 2+ pneumonitis.

METHODS AND MATERIALS

The model was built from a database of 234 lung cancer patients treated with radiotherapy (RT), of whom 43 were diagnosed with pneumonitis. The model augmented the predictive capability of the parametric dose-based Lyman normal tissue complication probability (LNTCP) metric by combining it with weighted nonparametric decision trees that use dose and nondose inputs. The decision trees were sequentially added to the model using a "boosting" process that enhances the accuracy of prediction. The model's predictive capability was estimated by 10-fold cross-validation. To facilitate dissemination, the cross-validation result was used to extract a simplified approximation to the complicated model architecture created by boosting. Application of the simplified model is demonstrated in two example cases.

RESULTS

The area under the model receiver operating characteristics curve for cross-validation was 0.72, a significant improvement over the LNTCP area of 0.63 (p = 0.005). The simplified model used the following variables to output a measure of injury: LNTCP, gender, histologic type, chemotherapy schedule, and treatment schedule. For a given patient RT plan, injury prediction was highest for the combination of pre-RT chemotherapy, once-daily treatment, female gender and lowest for the combination of no pre-RT chemotherapy and nonsquamous cell histologic type. Application of the simplified model to the example cases revealed that injury prediction for a given treatment plan can range from very low to very high, depending on the settings of the nondose variables.

CONCLUSIONS

Radiation pneumonitis prediction was significantly enhanced by decision trees that added the influence of nondose factors to the LNTCP formulation.

Chimioradiothérapie exclusive des cancers bronchiques non à petites cellules localement évolués

Chemoradiation is one of the major therapeutic options in thoracic oncology: besides surgery, the best treatment for early-stage tumors, and chemotherapy, not only used in metastatic tumors, but also in a neoadjuvant and adjuvant setting, chemoradiation is the standard strategy for unresectable locally advanced non-small cell lung cancer. Its current modalities include three-dimensional conformal techniques, allowing dose escalation and sequential and concurrent combination with new generation cytotoxic agents to occur. Phase III trials are currently evaluating the benefit from induction and consolidation chemotherapy in this setting. New techniques of radiation may also increase the efficacy and the feasibility of radiation. This constant progress makes chemoradiation one of the most promising combined treatments in thoracic oncology.

Cytokine profiling for prediction of symptomatic radiation-induced lung injury

PURPOSE

To analyze plasma cytokine profiles before the initiation of radiation therapy to define a cytokine phenotype that correlates with risk of developing symptomatic radiation-induced lung injury (SRILI).

METHODS AND MATERIALS

Symptomatic radiation-induced lung injury was evaluated in 55 patients (22 with SRILI and 33 without SRILI), according to modified National Cancer Institute common toxicity criteria. These plasma samples were analyzed by the multiplex suspension bead array system (Bio-Rad Laboratories; Hercules, CA), which included the following cytokines: interleukin (IL)-1beta, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p70, IL-13, IL-17, granulocyte/macrophage colony-stimulating factor, interferon-gamma, monocyte chemotactic protein 1, macrophage inflammatory protein 1beta, tumor necrosis factor alpha, and granulocyte colony-stimulating factor.

RESULTS

Significant differences in the median values of IL-8 were observed between patients with and without SRILI. Patients who did not develop SRILI had approximately fourfold elevated levels of IL-8 as compared with patients who did subsequently develop SRILI. Significant correlations were not found for any other cytokine in this study, including transforming growth factor beta1.

CONCLUSIONS

Patients with lower levels of plasma IL-8 before radiation therapy might be at increased risk for developing SRILI. Further studies are necessary to determine whether IL-8 levels are predictive of SRILI in a prospective trial and whether this marker might be used to determine patient eligibility for dose escalation.

Neoadjuvant Chemotherapy Followed by Late-Course Accelerated Hyperfractionated Radiation Therapy for Locally Advanced Non–Small-Cell Lung Cancer: Long-Term Results of a Phase I/II Clinical Trial

Toxicity, response, and long-term results of a definitive chemotherapy/radiation therapy (RT) protocol in patients with unresectable stage III non-small-cell lung cancer (NSCLC) were evaluated. Two cycles of cisplatin-based chemotherapy were delivered before RT, and another 2 cycles were added for patients who responded to the first 2 cycles of chemotherapy. The first course of radiation covered the primary lesion and elective nodal regions, given in 2 Gy per fraction, 5 days a week for a dose of 40 Gy. Late-course hyperfractionated accelerated RT was delivered to the gross tumor twice a day for an additional 27 Gy within 2 weeks, using 1.5 Gy per fraction. Fifty-three patients with unresectable stage IIIA (N2) and IIIB NSCLC were eligible for analysis. Twelve patients developed grade 3 neutropenia, and 3 patients developed grade 4 neutropenia. Grade 2 or 3 esophagitis was observed in 14 and 2 patients, respectively, and grade 2 or 3 pneumonitis was observed in 9 and 1 patient, respectively. Six patients developed grade 2 and 1 patient developed grade 3 late lung toxicity. The median survival time was 15.5 months. Twenty-six of 53 patients (49%) have died of locoregional progression inside the thorax. The distant metastasis rate was 59.5% (22 of 37 patients) for those who did not respond to chemotherapy and 18.8% (3 of 16 patients) for those who responded to chemotherapy (P = 0.006). Late-course hyperfractionated accelerated RT combined with induction chemotherapy was well tolerated and yielded long-term results that compare favorably with those of studies using 2 cycles of induction chemotherapy and conventional fractionated RT. However, local control was still discouraging.

Accelerated regrowth of non-small-cell lung tumours after induction chemotherapy

Induction chemotherapy of non-small-cell lung cancer (NSCLC) stage III with gemcitabine and cisplatin for downstaging of the tumour with the aim for further treatment with ionising radiation is one of the treatments for lung cancer patients. The purpose of this study was to investigate the influence of the waiting time for radiotherapy, that is, the interval between induction chemotherapy and radiotherapy, on the rate of tumour growth for patients with NSCLC. Interval times between the end of induction chemotherapy and date of diagnostic CT, planning CT and first day of radiotherapy were determined for 23 patients with NSCLC. Increase in gross tumour volume was measured for 18 patients by measuring the dimensions of the primary tumour and lymph node metastases on the diagnostic CT after induction chemotherapy and on the CT used for radiotherapy planning. For each patient, the volume doubling time was calculated from the time interval between the two CTs and ratio of the gross volumes on planning CT and diagnostic CT. The mean time interval between end of chemotherapy and day of diagnostic CT was 16 days, and till first day of radiotherapy 80.3 (range 29 – 141) days. In all, 41% of potentially curable patients became incurable in the waiting period. The ratio of gross tumour volumes of the two CTs ranged from 1.1 to 81.8 and the tumour doubling times ranged from 8.3 to 171 days, with a mean value of 46 days and median value of 29 days. This is far less than the mean doubling time of NSCLC in untreated patients found in the literature. This study shows that in the time interval between the end of induction chemotherapy and the start of radiotherapy rapid tumour progression occurs as a result of accelerated tumour cell proliferation: mean tumour doubling times are much shorter than those in not treated tumours. As a consequence, the gain obtained with induction chemotherapy with regard to volume reduction was lost in the waiting time for radiotherapy. We recommend diminishing the time interval between chemo- and radiotherapy to as short as possible.

Normal-tissue toxicities of thoracic radiation therapy: esophagus, lung, and spinal cord as organs at risk

The evolution of therapeutic approaches for lung cancer illustrates the trend for treatment intensification, with hopes that dose-intense chemotherapy regimens, higher radiation therapy (RT) doses, or novel fractionation schemes will result in prolongation of survival. Current chemotherapy- and RT-intense regimens may not be intensified further without addressing dose-limiting toxicities such as esophagitis. It is important to understand factors pre-disposing to esophagitis so that strategies to minimize its severity can be investigated. Pulmonary complications such as pneumonitis and fibrosis from RT (with or without chemotherapy) are dose and volume dependent. Methods to better identify the target tissues and improved RT-delivery systems may facilitate increasing target doses or reducing doses to adjacent normal tissues. Biologic predictors may allow clinicians in the future to individualize RT treatment based on a patient's toxicity risk profile. Radiation myelopathy is still the most feared radiation complication of lung cancer treatment. The authors address the known parameters that influence the incidence of thoracic radiation myelopathy and the putative factors that could be considered when a clinician may be required to push the spinal cord dose in favor of tumor control.

Three-dimensional conformal radiation therapy for non–small-cell lung cancer: A Phase I/II dose escalation clinical trial

PURPOSE

A prospective Phase I/II dose escalation study was conducted to determine the maximum tolerated dose (MTD) in three-dimensional conformal radiation therapy (3D-CRT) for non-small-cell lung cancer (NSCLC).

MATERIALS AND METHODS

MTD would be reached via a dose escalation study. After 42 Gy/21 fractions, 4.2 weeks by conventional fractionated irradiation through anteroposterior/posteroanterior fields, the 3D-CRT technique was used as boost. The planned total dose escalation depended on lung volume irradiated. According to the percentage of lung volume receiving >20 Gy, the patients were divided into three subgroups (i.e., <25%, 25%-37%, and >37%). The scheduled dose escalation began with 69 Gy and continued to 78 Gy. The boost doses were delivered at 3 Gy per fraction, once per day, five fractions per week. Each dose level includes 5 patients. Besides radiotherapy, all patients received neoadjuvant and adjuvant chemotherapy with MVP regimen (Mitomycin, Vindesine, cis-platium). The criterion for stopping further dose escalation was > or =20% of patients with > or =RTOG Grade 3 radiation pneumonitis.

RESULTS

Between June 1999 and February 2001, 50 patients had been enrolled in this study, including 4 with Stage II disease, 31 with Stage IIIa disease, and 15 with Stage IIIb disease. The dose escalation plan has been completed. All subgroups reached the highest predetermined dose levels (i.e., 78 Gy for the <25% subgroup, 78 Gy for the 25-37% subgroup, and 75 Gy for the >37% subgroup). Although none of the subgroups developed more than 20% of >/=Grade 3 acute pneumonitis, dose escalation was terminated because long-term follow-up was needed to observe late complications. Median follow-up time (MFT) for the entire group was 18 months (6-37 months). The most common acute complication was esophagitis in 56% of patients with RTOG Grade 1-2, and in 4% with Grade 3. Acute radiation pneumonitis developed in 36% of patients with RTOG Grade 1-2. Only 1 patient had Grade 3 pneumonitis, which was in the 25-37% subgroup at 75 Gy. The hematopoietic toxicity appeared in 58% of patients with Grade 1-2, and 8% with Grade 3. As to late complications, only 30% of patients developed pulmonary fibrosis of RTOG Grade 1-2. The median survival time for the entire group was 18 months. Two-year overall survival, locoregional progression-free rate, and distant metastasis rate were 44%, 40%, and 41%, respectively.

CONCLUSIONS

Although MFT was 18 months, it had not yet been declared because a longer follow-up was needed to observe the late complications. The 2-year overall survival of 44% was very encouraging and implied that 3D-CRT combined with chemotherapy would improve the outcome for locally advanced NSCLC.

Prognostic factors for local control in non-small-cell lung cancer treated with definitive radiation therapy

Radiotherapy plays an important role as a treatment for locally advanced non-small-cell lung cancer (NSCLC), but local failure still occurs in 70% to 80% of the patients. A retrospective analysis was carried out to evaluate the local control predictors for non-SCLC. From January 1990 to December 1996, 256 patients with stages I-IIIb NSCLC entered this analysis. All patients received definitive radiotherapy. The significance of prognostic variables on local control was evaluated using univariate analysis and Cox stepwise regression model. The prognostic index was calculated according to the value of each prognostic factor on local control. Median local progression-free survival time of the whole group was 9.7 months, and 1-, 3-, and 5-year actuarial local progression-free survival were 54%, 24%, and 19%, respectively. Univariate and multivariate analyses showed patients with smaller tumor volume, earlier clinical staging, and treated with higher total dose in shortened overall treatment time had better local control. Tumor volume, clinical staging, and radiotherapy methods were independent prognostic factors on local control. The prognostic index model could predict the local control condition of NSCLC treated with radiation therapy more effectively than a single variable such as TNM staging.

Predicting the risk of symptomatic radiation-induced lung injury using both the physical and biologic parameters V(30) and transforming growth factor beta

PURPOSE

To correlate the volume of lung irradiated with changes in plasma levels of the fibrogenic cytokine transforming growth factor beta (TGFbeta) during radiotherapy (RT), such that this information might be used to predict the development of symptomatic radiation-induced lung injury (SRILI).

METHODS AND MATERIALS

The records of all patients with lung cancer treated with RT with curative intent from 1991 to 1997 on a series of prospective normal tissue injury studies were reviewed. A total of 103 patients were identified who met the following inclusion criteria: (1) newly diagnosed lung cancer of any histology treated with RT +/- chemotherapy with curative intent; (2) no evidence of distant metastases or malignant pleural effusion; (3) no thoracic surgery after lung RT; (4) no endobronchial brachytherapy; (5) follow-up time more than 6 months; (6) plasma TGFbeta1 measurements obtained before and at the end of RT. The concentration of plasma TGFbeta1 was measured by an enzyme-linked immunosorbent assay. Seventy-eight of the 103 patients were treated with computed tomography based 3-dimensional planning and had dose-volume histogram data available. The endpoint of the study was the development of SRILI (modified NCI [National Cancer Institute] common toxicity criteria).

RESULTS

The 1-year and 2-year actuarial incidence of SRILI for all 103 patients was 17% and 21%, respectively. In those patients whose TGFbeta level at the end of RT was higher than the pre-RT baseline, SRILI occurred more frequently (2-year incidence = 39%) than in patients whose TGFbeta1 level at the end of RT was less than the baseline value (2-year incidence = 11%, p = 0.007). On multivariate analysis, a persistent elevation of plasma TGFbeta1 above the baseline concentration at the end of RT was an independent risk factor for the occurrence of SRILI (p = 0.004). The subgroup of 78 patients treated with 3-dimensional conformal radiotherapy, who consequently had dose-volume histogram data, were divided into groups according to their TGFbeta1 kinetics and whether their V(30) level was above or below the median of 30%. Group I (n = 29), with both a TGFbeta1 level at the end of RT that was below the pre-RT baseline and V(30) < 30%; Group II (n = 35), with a TGFbeta1 level at the end of irradiation that was below the baseline but a V(30) > or = 30% or with a TGFbeta1 level at the end of RT that was above the pre-RT baseline but V(30) < 30%; Group III (n = 14), with both a TGFbeta1 level at the end of RT that was above the baseline and V(30) > or = 30%. A significant difference was found in the incidence of SRILI among these three groups (6.9%, 22.8%, 42.9%, respectively, p = 0.02).

CONCLUSIONS

(1) An elevated plasma TGFbeta1 level at the end of RT is an independent risk factor for SRILI; (2) The combination of plasma TGFbeta1 level and V(30) appears to facilitate stratification of patients into low, intermediate, and high risk groups. Thus, combining both physical and biologic risk factors may allow for better identification of patients at risk for the development of symptomatic radiation-induced lung injury.

Accelerated hyperfractionation in patients with non-small cell bronchogenic cancers as a cost-effective and user- and patient-friendly schedule

We developed an accelerated hyperfractionation schedule with acceptable effect and toxicity in non-small cell bronchogenic carcinomas. An evolutionary institutional pilot was initiated in March 1995 as a modification of Radiation Therapy Oncology Group (RTOG) 9205, thrice-daily fractionation schedule. Twenty-nine patients with bronchogenic and 7 with head and neck cancers had treatment initiated and completed. A dose of 1.2 Gy was delivered to a mediastinal plus tumor field concomitantly with synchronous boost of 0.6 Gy to a limited volume of gross tumor (twice daily for 21 treatments days in 4 weeks) with a total dose being 75.60 Gy to the primary gross tumor and 50.4 Gy to the elective volume. The bronchogenic cancers were stages IB (medically unresectable, n = 3), IIB (n = 4), IIIA (n = 4), or IIIB (n = 18). Eleven patients had squamous cell cancers, 13 adenocarcinomas, 1 large cell, and 2 carcinomas not specified. With 12 months median follow-up, tolerance has been excellent without any patient complaining of at least Oncology Nursing Society (ONS) grade 3 esophagitis; treatment interruptions occurred in only one patient after 8 days. Weight loss occurred in 12 patients, averaging 4.8% for these patients and 2% overall. Seven patients had a complete response and 20 a partial response. Median survival was 12 months, 1-year survival 58%, 2-year 21%, and 3-year 18%. Seven patients with bronchogenic cancer are still alive. Seven head and neck cancer patients were treated, in which five had base of tongue tumors stage T2 to 4, N0 to N1. Pharyngitis and mucositis were problematic in at least four patients. The outcomes are comparable with other RTOG experience. Hyperfractionated synchronous concomitant boost of total tumor dose to 75.6 Gy in 4 weeks for bronchogenic patients was well tolerated and acceptable to physicians and patients.

The impact of overall treatment time on outcomes in radiation therapy for non-small cell lung cancer

PURPOSE

A retrospective study was carried out to evaluate the impact of overall treatment time (OTT) on the results of radiation therapy for non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

From Jan. 1990 to Dec. 1996, 256 patients with stages I-IIIb NSCLC entered this analysis. All patients received definitive radiotherapy. Biologically effective dose (BED) was used to standardize the irradiation effects. The correlation between OTT and local progression-free survival was analyzed by linear-regression and Cox proportional hazard models. The prognostic variables for survival and distant metastasis were also briefly studied.

RESULTS

OTT had been shortened in 64 patients because of an accelerated hyperfractioned irradiation, while OTT was prolonged i n 114 patients due to interruptions of irradiation courses. The main ca uses of interruption were machine breakdown or delayed preparations of c errobend block for boost fields (55%), holidays (11%) and treatment toxi city and side effects (34%). Patients tre ated with prolonged OTT (> 45 days) had significant poorer local progression-free survival than whom with OTT of </=45 days, 1, 3 and 5 year actuarial local progression-free survivals being 49, 17 and 15% for the former, and 74, 35 and 25% for the latter, respectively (P<0.001). BED-T that contained the factor of OTT correlated directly to local controls, which implied that BED-T represented radiobiological effects accurately, in other words, OTT had played a role in determining the radiobiological effects. Linear-regression on 103 cases treated with BED of 80-85 Gy(10) showed that 3 year local progression-free survival decreased by 9% per week with prolongation of OTT, or vice versa it increased by 9% per week with shortening OTT in an OTT range of 30-76 days. Cox multivariate analyses confirmed that OTT was an independent prognostic factor for local controls.

CONCLUSION

OTT may have played an important role in determining local controls in radiotherapy for NSCLC. One should always keep in mind to make the OTT as short as possible, provided the patients can tolerate it, and to reduce irradiation interruptions for whatever reasons to a minimum.

Accelerated hyperfractionation for bronchogenic cancer: Radiation Therapy Oncology Group 9205

RTOG 92-05 was a phase II trial developed to evaluate the feasibility, toxicity, and acceptance of a three times daily accelerated hyperfractionation radiation therapy schedule delivering 110 cGy, three times daily, to 79.2 Gy uncorrected tumor dose in 72 fractions, in 24 treatment days, in patients with bronchogenic cancer. The radiographically visible tumor received accelerated hyperfractionation and the other radiation volume received standard hyperfractionation. Three times a day, a dose of 110 cGy was delivered, with an interfractional interval of 4 hours; the middle fraction was a gross tumor boost. This schedule allowed treatment to be completed in approximately 4 1/2 weeks in an effort to minimize repopulation, to have a better biologically modeled therapeutic ratio than other schedules that have been completed in cooperative groups, and to use doses within cooperative group experience. In 33 months 35 patients were entered into the study; 15 of the patients had squamous cell carcinomas, 10 had adenocarcinomas, 8 had large-cell undifferentiated carcinomas, and 2 had unspecified non-small-cell cancers. Nineteen patients had AJCC stage IIIB; 13, IIIA; 14, T4; 10, T3; 13, N2; and 7, N3. Twenty-one patients (60%) had greater than 5% weight loss. The Karnofsky performance status was 90 to 100 in 12 patients and 70 to 80 in 23 patients. Treatment was completed in 91% of patients. Acute toxicity >RTOG grade II occurred in three patients: one skin, one lung, and two esophagus (one each III and IV, the only grade IV in the study). Overall late toxicity > or = grade III occurred in six patients: three lung, one thyroid, one esophagus, and one subcutaneous tissue (all grade III). The median survival was 10.5 months, 1-year survival was 42%, and 3-year survival was 18%. The outcome in this group of patients with many adverse prognostic variables compared favorably to prior RTOG radiation-alone studies.

Toxicity of high-dose radiotherapy combined with daily cisplatin in non-small cell lung cancer: results of the EORTC 08912 phase I/II study. European Organization for Research and Treatment of Cancer

The purpose of this work was to study the feasibility of concurrent chemoradiation in patients with inoperable non-small cell lung cancer (NSCLC). 40 patients with inoperable NSCLC were treated with escalating doses of radiotherapy and cisplatin (cDDP). The radiation dose was increased step by step from 60.5 to 66 Gy in daily fractions of 2.75 Gy. Chemotherapy was also increased step by step from 20 to 24 daily doses of cDDP 6 mg/m(2) and given concurrently with radiotherapy. A dose of 40 Gy/2 Gy/20 fractions (fx) was given to the EPTV (elective planning target volume) which included the gross tumour volume with a margin of 2 cm and part of or the entire mediastinum. During each session a boost dose of 0.75 Gy was given simultaneously to the BPTV (boost planning target volume), which encompassed the GTV (gross tumour volume) with a margin of 1 cm, for the first 20 fx, so the total dose to the tumour was 55 Gy. Cisplatin 6 mg/m(2) was given 1 h prior to radiotherapy at each fraction. From then on the dose of radiation to the BPTV and the dose of cDDP were increased step by step. In group I the BPTV was irradiated with two extra fractions of 2.75 Gy to a total dose of 60. 5 Gy without cDDP. In group II the same total dose of 60.5 Gy was given but the last two fractions were combined with cDDP. In group III four extra fractions of 2.75 Gy were given to the BPTV to a total dose of 66 Gy, only two of these fractions combined with cDDP. Finally, in group IV a total dose of 66 Gy was given in 24 fractions, all fractions combined with cDDP. All patients were planned by means of a CT-based conformal treatment planning. The maximal length of the oesophagus receiving >/=60.5 Gy was 11 cm. 40 patients were evaluable for acute and late toxicity and for survival. Acute toxicity grade >/=3 (common toxicity criteria, CTC) was rarely observed; nausea/vomiting in 3 patients (8%), leucopenia in 2 patients (5%), thrombocytopenia in 2 patients (5%), whilst 2 patients (5%) suffered from severe weight loss. Late side-effects (European Organization for Research and Treatment of Cancer/Radiation Therapy Oncology Group, EORTC/RTOG) were: oesophageal toxicity >/=grade 3 in 2 patients (5%) and radiation pneumonitis grades 1 (3%) and 2 (3%) in 1 patient each. Overall actuarial 1- and 2-year survival was 53% and 40%, respectively. The 1- and 2-year local disease-free interval was 65% and 58% respectively. Radiotherapy at a dose of 66 Gy/2.75 Gy/24 fx combined with daily cDDP 6 mg/m(2) given over 5 weeks is feasible and results in a good local disease-free interval and a good survival rate. This treatment schedule is at present being tested as one of the two treatment arms of EORTC phase III study protocol 08972/22973.

Hyperfractionated accelerated radiotherapy (HART) for inoperable, nonmetastatic non-small cell lung carcinoma of the lung (NSCLC): results of a phase II study for patients ineligible for combination radiochemotherapy

PURPOSE

To evaluate a hyperfractionated and accelerated radiotherapy (HART) protocol in patients with inoperable non-small cell lung carcinoma (NSCLC) who were ineligible for combination radiochemotherapy studies.

METHODS AND MATERIALS

From February 1989 through August 1994, 23 patients ineligible for available combined modality protocols in our institution were enrolled and treated with HART, consisting of 63 Gy given in 42 fractions of 1.5 Gy each, twice daily, with a minimum time interval of 6 h between fractions, 5 days a week, over an elapsed time of 4.2 weeks, or 29 days. There was no planned interruption.

RESULTS

The 1-, 2-, and 3-year survival rates were 61%, 39%, and 19%, respectively, with a median survival of 16.8 months. At the time of analysis, 4 patients are alive and 19 have died, 16 from NSCLC and 3 from cardiac disease. Overall response rate was 48%, with 22% of patients achieving a complete response and 26% a partial response. Correlation between acute response rate and survival was poor. First site of relapse was local-regional in 8 patients (35%), distant in 6 patients (26%), and local-regional and distant in 4 (17%) patients. One patient had Grade IV and 2 had Grade III esophagitis. One patient presented with chronic Grade III lung toxicity. There were no treatment-related deaths.

CONCLUSION

In this group of 23 patients ineligible for radiochemotherapy, this HART regime was quite feasible and was followed by little toxicity. Results in this particularly poor prognosis NSCLC patient category should be compared to series with a similar patient profile; however, median survival is at least similar to that obtained in recent series of combination radiochemotherapy.

Radiotherapy for lung cancer: target splitting by asymmetric collimation enables reduction of radiation doses to normal tissues and dose escalation

PURPOSE

This study was performed to develop a method of reducing the radiation doses to normal thoracic tissues, increasing the target dose, especially in the primary radiotherapy of non-small cell lung cancer (NSCLC), and to evaluate acute/subacute toxicity of dose escalation.

METHODS AND MATERIALS

From December 1195 to March 1998, the technique of target splitting has been applied to 58 patients. In this period, 30 patients were treated with doses > 80 Gy (ICRU-specification, mean 85.1 Gy, range 80. 1-90.2 Gy). The target volume is split into a cranial part (e.g., upper mediastinum) and a caudal part (e.g., primary tumor and middle mediastinum). Both volumes are planned and treated independently, using conformal irradiation techniques for both parts with half-collimated fields to prevent over- or underdosage in the junction plane. After fine-adjustment of the jaws, a verification film, exposed in a polymethylmethacrylate (PMMA) phantom, demonstrates the homogeneity of dose in the entire target volume. For comparison with conventional techniques, planning to identical doses is performed for 5 patients. Dose-volume histograms (DHVs) for normal lung tissue are presented for both methods.

RESULTS

The irradiated volume of normal tissue of the ipsilateral lung can be lowered at dose levels > or = 65, > or =45 Gy, and > or = 20 Gy to values of 37% (range 25-54%), 49% (range 46-54%), and 86% (range 55-117%), respectively. Other organs at risk, such as heart or esophagus, can also be spared significantly. Only 1 patient showed a transient grade 3 toxicity (pneumonitis), and there where no grade 4 acute/subacute side-effects. Two patients with Stage III A central tumors in close proximity to the large vessels died due to a pulmonary hemorrhage 2 and 4 months after therapy, respectively. No patient developed esophagitis. Antimycotic prophylaxis for esophagitis and posttherapeutic steroid prophylaxis for pneumonitis for several weeks were routinely used.

CONCLUSION

The technique of target splitting by asymmetric collimation helps to increase conformation, and thus enhances the sparing of normal tissues. It can be used whenever there is a marked difference in the shape of the planning target volume (PTV) in a cranio-caudal direction. This technique can principally be handled with 2D-planning systems, because it is coplanar. We consider target splitting as an important tool for dose escalation in the primary radiotherapy of NSCLC, that should also be used for other lung cancer patients necessitating moderate doses only.