Role of SPECT in Radiotherapy of Lung Cancer and Toxicity Evaluation

Role of SPECT in Radiotherapy Treatment Planning and Toxicity Evaluation for the Patients With Stage I-III NSCLC

Overall objective of the study is to compare the use of SPECT in radiotherapy treatment planning with standard CT-based radiotherapy for stage I-III non-small-cell lung cancer patients

Primary objective:

-To compare the rate of grade 2 or higher pneumonitis amongst patients with stage III NSCLC treated with radiotherapy using SPECT in radiotherapy treatment planning versus standard CT-based radiotherapy planning;

Secondary Objectives:

• To evaluate SPECT as a tool to predict lung toxicity;
• To establish estimates for the incidence and severity of pulmonary tissue effects observed in stage III NSCLC patients treated with radiotherapy;
• To generate hypotheses for subsequent use of SPECT-CT-based treatment planning as a method for minimization of toxicity risks
• To generate hypotheses for modeling studies of SPECT-CT-based treatment planning for dose-escalation;
• To compare the loco-regional control, time to progression and overall survival of patients treated with SPECT-based plan versus standard CT-based plan
• To compare the quality of life in patients randomized to the two study arms.

This trial is a single centre observational study. All patients will irrespective of their registration in the trial receive radiotherapy according to the standard treatment regimen at the Department of Oncology, Aarhus University Hospital. Participation implies baseline and follow-up procedures. In the treatment planning phase patients will be randomized to one of the following arms: Arm 1 SPECT/CT-based treatment plan with functional dose-volume parameters and Arrm 2 Standard CT-based plan with conventional dose-volume parameters.

The trial will consist of two parts. To initiate the trial a pilot study (part 1) will be performed to determine the feasibility in our setting at Aarhus University Hospital as it is described in the literature. Consecutive patients will be enrolled in the pilot study during 1-year period. The interim analysis after one year of enrollment will be performed to determine what patients are most likely to benefit from functional radiotherapy planning based on SPECT. The main objective of this part is to determine whether V/Q-SPECT data are valid and usable in the radiotherapy planning. The timing for acute and late follow-up SPECT will be determined. Randomized trial (part 2) will be performed thereafter.

Statistical analysis. The randomization by permitted blocks method will be used to allocate patients to treatment arm. Stratification factors will be age, gender, disease stage, histology, concurrent chemotherapy and irradiated volumes.

The chi-squire test (α=0.10) with the continuity correction will be used for analysis of the primary analysis. For all other comparisons, two-sided analyses will be performed and a p-value of 0.05 or less will be considered statistically significant. 95% confidence intervals will be constructed for outcomes of interest. Descriptive statistics will be used to summarize patient characteristics and outcomes by intervention arm. Differences in outcomes between intervention arms will be compared by using paired t-tests, Wilcoxon rank sum tests or McNemar tests as appropriate. Adjusting for stratification factors will be performed using logistic regression or linear regression. Time-to-event analyses will be estimated using the Kaplan-Meier method, and compared using Cox proportional hazards regression.

Estimation of the relationship between dose-volume parameters and toxicity will be evaluated using logistic regression analyses. Within patients who were planned using SPECT, the association between dose-volume parameters calculated using SPECT and those calculated under a CT-plan will be evaluated using correlation coefficients.

All patients who are randomized will be included in the analysis of safety and efficacy outcomes. Secondary analyses may be performed on those patients only on those who received radiotherapy as per the treatment plan based on SPECT or CT as per the intervention arm. Any patient who is randomized but does not receive radiotherapy based on the intervention allocated treatment plan will be described in detail along with the reason for not receiving the prescribed plan.

Inclusion Criteria:

• Stage I-III non-small cell lung cancer, histologically verified
• Referred for definitive radiotherapy to the Department of Oncology, Aarhus University Hospital
• Meet the criteria for curatively intended radiotherapy described in details in the national guidelines
• Concurrent chemotherapy is accepted
• Adults over 18, that have given oral and written informed consent before patient registration
• The patients can only be randomized in this trial once

Exclusion Criteria:

• other uncontrolled malignancies
• human albumin allergy
• any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule