Three-dimensional conformal radiotherapy for lung cancer: promises and pitfalls

An IMRT/VMAT Technique for Nonsmall Cell Lung Cancer

The study is to investigate a Hybrid IMRT/VMAT technique which combines intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) for the treatment of nonsmall cell lung cancer (NSCLC). Two partial arcs VMAT, 5-field IMRT, and hybrid plans were created for 15 patients with NSCLC. The hybrid plans were combination of 2 partial arcs VMAT and 5-field IMRT. The dose distribution of planning target volume (PTV) and organs at risk (OARs) for hybrid technique was compared with IMRT and VMAT. The monitor units (MUs) and treatment delivery time were also evaluated. Hybrid technique significantly improved the target conformity and homogeneity compared with IMRT and VMAT. The mean delivery time of IMRT, VMAT, and hybrid plans was 280 s, 114 s, and 327 s, respectively. The mean MUs needed for IMRT, VMAT, and hybrid plans were 933, 512, and 737, respectively. Hybrid technique reduced V5, V10, V30, and MLD of normal lung compared with VMAT and spared the OARs better with fewer MUs with the cost of a little higher V5, V10, and mean lung dose (MLD) of normal lung compared with IMRT. Hybrid IMRT/VMAT can be a viable radiotherapy technique with better plan quality.

IMMUNEPOTENT CRP (bovine dialyzable leukocyte extract) adjuvant immunotherapy: a phase I study in non-small cell lung cancer patients

BACKGROUND

IMMUNEPOTENT CRP is a mixture of low molecular weight substances, some of which have been shown to be capable of modifying the immune response. We evaluated the response and adjuvant effect of IMMUNEPOTENT CRP on non-small cell lung cancer (NSCLC) patients in a phase I clinical trial.

METHODS

Twenty-four NSCLC patients were included in the study and divided into two groups. Group 1 received a conventional treatment of 5400 cGy external radiotherapy in 28 fractions and chemotherapy consisting of intravenous cisplatin (40 mg/m(2)) delivered weekly for 6 weeks. Group 2 received the conventional treatment plus IMMUNEPOTENT CRP (5 U) administered daily. We performed clinical evaluation by CT scan and radiography analysis, and determined the quality of life of the patients with the Karnofsky performance scale. A complete blood count (red and white blood cell tests), including flow cytometry analysis, blood work (alkaline phosphatase test) and a delayed-type hypersensitivity (DTH) skin test for PPD, Varidase and Candida were performed.

RESULTS

The administration of IMMUNEPOTENT CRP induced immunomodulatory activity (increasing the total leukocytes and T-lymphocyte subpopulations CD4(+), CD8(+), CD16(+) and CD56(+), and maintaining DHT) and increased the quality of the patients' lives, suggesting immunologic protection against chemotherapeutic side-effects in NSCLC patients.

DISCUSSION

Our results suggest the possibility of using IMMUNEPOTENT CRP alongside radiation and chemotherapy for maintaining the immune system and increasing the quality of life of the patients.

Comparison of CT and positron emission tomography/CT coregistered images in planning radical radiotherapy in patients with non-small-cell lung cancer

Imaging with F-18 fluorodeoxyglucose positron emission tomography (PET) significantly improves lung cancer staging, especially when PET and CT information are combined. We describe a method for obtaining CT and PET images at separate acquisitions, which allows coregistration and incorporation of PET information into the radiotherapy (RT) planning process for non-small-cell lung cancer. The influence of PET information on RT planning was analysed for 10 consecutive patients. Computed tomography and PET images were acquired with the patient in an immobilization device, in the treatment position. Using specially written software, PET and CT data were coregistered using fiducial markers and imported into our RT planning system (Cadplan version 6). Treatment plans were prepared with and without access to PET/CT coregistered images and then compared. PET influenced the treatment plan in all cases. In three cases, geographic misses (gross tumour outside planning target volume) would have occurred had PET not been used. In a further three cases, better planning target volume marginal coverage was achieved with PET. In four patients, three with atelectasis, there were significant reductions in V20 (percentage of the total lung volume receiving 20 Gy or more). Use of coregistered PET/CT images significantly altered treatment plans in a majority of cases. This method could be used in routine practice at centres without access to a combined PET/CT scanner .

Toxicity and outcome of a phase II trial of taxane-based neoadjuvant chemotherapy and 3-dimensional, conformal, accelerated radiotherapy in locally advanced nonsmall cell lung cancer

BACKGROUND

The objective of this study was to evaluate prospectively the acute and late adverse effects of taxane/carboplatin neoadjuvant chemotherapy and 3-dimensional, conformal radiotherapy in patients with locally advanced nonsmall cell lung cancer (NSCLC).

METHODS

Forty-two patients were entered into a nonrandomized Phase II study of continuous, hyperfractionated, accelerated radiotherapy (CHART) week-end less (CHARTWEL) to a dose of 60 grays (Gy). Three cycles of chemotherapy were given over 9 weeks before radiotherapy. Dose escalation with paclitaxel was from 150 mg/m2 to 225 mg/m2. Systemic toxicity to chemotherapy was monitored throughout. Radiation-induced, early, adverse effects were assessed during the first 9 weeks from the start of radiotherapy, and late effects were assessed from 3 months onward. Overall survival, disease-free survival, and locoregional tumor control also were monitored.

RESULTS

Twenty percent of patients failed to receive chemotherapy as planned, primarily because of neutropenia. The incidence of Dische Dictionary Grade >or=2 and Grade >or=3 dysphagia was 57.5% and 10%, respectively, with an average duration of 1.2 weeks and 1.5 days, respectively. By 9 weeks, <3% of patients were symptomatic; and, eventually, all acute reactions were healed, and there has been no evidence of consequential damage. At 6 months, the actuarial incidence of moderate-to-severe pneumonitis was 10%. During this time, all patients were free of severe pulmonary complications. Actuarial estimates of Grade >or=2 late lung dysfunction were 3% at 1 year, 10% at 2 years, and remained at this level thereafter. The actuarial 3-year locoregional control and overall survival rates were 54% and 45%, respectively.

CONCLUSIONS

Neoadjuvant chemotherapy followed by 3-dimensional, conformal CHARTWEL 60-Gy radiotherapy in patients with advanced NSCLC was feasible and was tolerated well. Historic comparisons indicated that locoregional tumor control is not compromised by the use of conformal techniques.

Feasibility of sparing lung and other thoracic structures with intensity-modulated radiotherapy for non-small-cell lung cancer

PURPOSE

To investigate the possibility of using intensity-modulated radiotherapy (IMRT) to reduce the irradiated volumes of the normal lung and other critical structures in the treatment of non-small-cell lung cancer (NSCLC) and to investigate the effect of IMRT on the potential of spreading low doses to large volumes of normal tissues in such treatment.

METHODS AND MATERIALS

A retrospective treatment planning study was performed to compare IMRT and conventional three-dimensional conformal radiation therapy (3D-CRT) for 10 NSCLC patients (Stage I-IIIB). In the IMRT plans, three to nine coplanar beams were designed to treat 95% of the planning target volume with 63 Gy and to minimize the volumes of the normal lung, esophagus, heart, and spinal cord irradiated above their tolerance doses. The two types of plans were compared with respect to the planning target volume coverage, dose-volume histograms, and other dosimetric indexes of the normal structures.

RESULTS

Comparing the nine-beam IMRT plan with the 3D-CRT plan, the percentage of lung volume that received >20 Gy and the mean lung dose were reduced for all cases, with a median reduction of 8% and 2 Gy, respectively. An additional reduction of the >5-Gy volume and >10-Gy volume for the lung and thoracic tissue was more difficult with IMRT, although still possible using fewer beams in IMRT. The integral dose to the entire thorax was equivalent and even reduced for 8 of 10 cases using IMRT.

CONCLUSION

It is possible to reduce the volumes of low doses (such as the >10-Gy volume and >20-Gy volume) for thoracic normal tissues using IMRT. The increased integral dose and low-dose volumes can be avoided for IMRT if such concerns are addressed carefully in the inverse planning process and with optimization of the IMRT beam configuration.