The impact of three-dimensional radiation on the treatment of non-small cell lung cancer

Radiation Therapy for Lung Cancer: Imaging Appearances and Pitfalls

Radiation therapy is part of a multimodality treatment approach to lung cancer. The radiologist must be aware of both the expected and the unexpected imaging findings of the post-radiation therapy patient, including the time course for development of post- radiation therapy pneumonitis and fibrosis. In this review, a brief discussion of radiation therapy techniques and indications is presented, followed by an image-heavy differential diagnostic approach. The review focuses on computed tomography imaging examples to help distinguish normal postradiation pneumonitis and fibrosis from alternative complications, such as infection, local recurrence, or radiation-induced malignancy.

Impact of artificial intelligence on clinical radiography practice: Futuristic prospects in a low resource setting

OBJECTIVES

Current trends in clinical radiography practice include the integration of artificial intelligence (AI) and related applications to improve patient care and enhance research. However, in low resource countries there are unique barriers to the process of AI integration. Using Ghana as a case study, this paper seeks to discuss the potential impact of AI on future radiographic practice in low-resource settings. The opportunities, challenges and the way forward to optimise the potential benefits of AI in future practice within these settings have been explored.

KEY FINDINGS

Some of the barriers to AI integration into radiographic practice relate to lack of regulatory and legal policy frameworks and limited resource availability including unreliable internet connectivity and low expert skillset.

CONCLUSION

These barriers notwithstanding, AI presents a great potential to the growth of medical imaging and subsequently improving quality of healthcare delivery in the near future. For example, AI-enabled radiographer reporting has a potential to improving quality of healthcare, especially in low-resource settings like Ghana with an acute shortage of radiologists. In addition, futuristic AI-enabled advancements such as synthetic cross-modality transfer where images from one modality are used as a baseline to generate a corresponding image of another modality without the need for additional scanning will be of particular benefit in low-resource settings.

IMPLICATIONS FOR PRACTICE

The urgent need for inclusion of AI modules for the training of the radiographer of the future has been suggested. Recommendations for development of AI strategies by national societies and regulatory bodies will harmonise the implementation efforts. Finally, there is need for collaboration between clinical practitioners and academia to ensure that the future radiography workforce is well prepared for the AI-enabled clinical environment.

A new method for risk factor assessment of organs at risk including conformity index in radiotherapy treatment plan

Introduction:

A comprehensive analysing method has been required since long in the field of radiotherapy. The basic purpose of all techniques has been to deliver the prescribed dose safely to the target volume containing tumour and as well as to reduce dose to organs at risk (OARs). The detailed comparison between different treatment techniques is very difficult and inexplicit as well. The gradual improvement in imaging software has made easy to users to assess spatial arrangement of tumour, critical organs and isodose lines in the form of a single 3D representation that can be observed from all angles. The conformity index (CI) alone cannot provide practical information about treatment plans as it is a single isodose line quantity.

Aim:

The aim of this study was to develop a new method to assess the degree of damage numerically for OARs along with CI assessment for the target.

Materials and Methods:

The radiotherapy plans of 30 patients of different sites, diagnosed as cancer, were selected for this study irrespective of gender. Out of 30 cases, 8 plans were of head and neck, 2 were of glyoblastoma (GBM), 10 were of pelvis, 5 were of left breast and other 5 were of oesophagus cancer. The mean age was 42 years ranging from 31 to 72 years. Patient’s consents were taken before starting the treatment and carried out this research. Risk factor (RF) for OARs depends on volume of irradiation (VVOI), total volume of the organ (VTVO) and tolerance dose (DTDO). All radiotherapy plans (Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT)) were generated using eclipse planning system, version 11.0 (Varian Medical System, Palo Alto, California, USA).

Result:

The formula developed to assess degree of damage of OARs including CI of the target is risk factor conformity index (RFC) = CI + RF. In head and neck cases, for right parotid, the maximum value of RF is 1·50 and minimum value is observed as 0·97. Optic nerve, brainstem and spinal cord are completely safe as their RF values are found to be 0 on RF scale.

Conclusion:

RFC is a comprehensive evaluation tool encompassing a wider range of clinically relevant parameters, isodose volumes and tolerance dose of OARs. It is an advance analysing method to check both the qualitative and quantitative nature of a conformal plan, and at the same time, it assesses the degree of damage of OARs.

If RF ≥ 1, then OAR will be completely damaged as a result of irradiation.

If RF = 0, then OAR will remain safe totally during the course of irradiation.

Antitumor, Inhibition of Metastasis and Radiosensitizing Effects of Total Nutrition Formula on Lewis Tumor-Bearing Mice

Non-small-cell lung cancer (NSCLC) causes high mortality. Radiotherapy is an induction regimen generally applied to patients with NSCLC. In view of therapeutic efficacy, the outcome is not appealing in addition to bringing about unwanted side effects. Total nutrition is a new trend in cancer therapy, which benefits cancer patients under radiotherapy. Male C57BL/6JNarl mice were experimentally divided into five groups: one control group, one T group (borne with Lewis lung carcinoma but no treatment), and three Lewis lung carcinoma-bearing groups administrated with a total nutrition formula (T + TNuF group), a local radiotherapy plus daily 3 Gy in three fractions (T + R group), or a combination TNuF and radiotherapy (T + R + TNuF group). These mice were assessed for their mean tumor volumes, cachectic symptoms and tumor metastasis. TNuF administration significantly suppressed tumor growth and activated apoptotic cell death in NSCLC-bearing mice under radiation. The body-weight gain was increased, while the radiation-induced cachexia was alleviated. Analysis of mechanisms suggests that TNuF downregulates EGFR and VEGF signaling pathways, inhibiting angiogenesis and metastasis. In light of radiation-induced tumor cell death, mitigation of radiation-induced cachexia and inhibition of tumor cell distant metastasis, the combination of TNuF and radiotherapy synergistically downregulates EGFR and VEGF signaling in NSCLC-bearing mice.

Integration of rotational angiography enables better dose planning in Gamma Knife radiosurgery for brain arteriovenous malformations

OBJECTIVE

In Gamma Knife radiosurgery (GKS) for arteriovenous malformations (AVMs), CT angiography (CTA), MRI, and digital subtraction angiography (DSA) are generally used to define the nidus. Although the AVM angioarchitecture can be visualized with superior resolution using rotational angiography (RA), the efficacy of integrating RA into the GKS treatment planning process has not been elucidated.

METHODS

Using data collected from 25 consecutive patients with AVMs who were treated with GKS at the authors’ institution, two neurosurgeons independently created treatment plans for each patient before and after RA integration. For all patients, MR angiography, contrasted T1 imaging, CTA, DSA, and RA were performed before treatment. The prescription isodose volume before (PIVB) and after (PIVA) RA integration was measured. For reference purposes, a reference target volume (RTV) for each nidus was determined by two other physicians independent of the planning surgeons, and the RTV covered by the PIV (RTVPIV) was established. The undertreated volume ratio (UVR), overtreated volume ratio (OVR), and Paddick’s conformal index (CI), which were calculated as RTVPIV/RTV, RTVPIV/PIV, and (RTVPIV)2/(RTV × PIV), respectively, were measured by each neurosurgeon before and after RA integration, and the surgeons’ values at each point were averaged. Wilcoxon signed-rank tests were used to compare the values obtained before and after RA integration. The percentage change from before to after RA integration was calculated for the average UVR (%ΔUVRave), OVR (%ΔOVRave), and CI (%ΔCIave) in each patient, as ([value after RA integration]/[value before RA integration] − 1) × 100. The relationships between prior histories and these percentage change values were examined using Wilcoxon signed-rank tests.

RESULTS

The average values obtained by the two surgeons for the median UVR, OVR, and CI were 0.854, 0.445, and 0.367 before RA integration and 0.882, 0.478, and 0.463 after RA integration, respectively. All variables significantly improved after compared with before RA integration (UVR, p = 0.009; OVR, p < 0.001; CI, p < 0.001). Prior hemorrhage was significantly associated with larger %ΔOVRave (median 20.8% vs 7.2%; p = 0.023) and %ΔCIave (median 33.9% vs 13.8%; p = 0.014), but not %ΔUVRave (median 4.7% vs 4.0%; p = 0.449).

CONCLUSIONS

Integrating RA into GKS treatment planning may permit better dose planning owing to clearer visualization of the nidus and, as such, may reduce undertreatment and waste irradiation. Further studies examining whether the observed RA-related improvement in dose planning also improves the radiosurgical outcome are needed.

A new index: Triple Point Conformity Scale (CS3) and its implication in qualitative evaluation of radiotherapy plan

Background

Across the history of radiotherapy, with gradual technological progress and various methods of irradiation, the purpose has always been to deliver homogeneously 100% of the prescribed dose to 100% of the target volume containing the identifiable tumour and/or tumour cells potentially present while limiting the dose to adjacent normal tissues.

Material and methods

The formula for triple point conformity scale is: CS3=(V95+V100+V105)/3VT. (a) Lower limit determination: CS3=(VT+0·93 VT+0·0)/3VT=0·643; (b) Upper limit determination: in order to find out an empirical relation in between V105 and VT, we studied over 593 cancer patients of various sites by taking planning target volume as target, and an empirical relation is derived out as: V105/VT=0·0007. Hence, CS3=(VT+VT+0·0007 VT)/3VT=0·6667~0·667.

Result

Upper and lower limits of CS3 have been calculated at 0·643 and 0·667, respectively. Maximum value of CS3 index is recorded 0·656 while minimum value is 0·478.

Discussion

The CS3 scale constitutes an attractive tool because it could facilitate decisions during analysis of various treatment plans proposed for conformal radiotherapy. Its major advantages are its simplicity and integration of multiple parameters.

Conclusion

The triple point conformity scale (CS3) provides better qualitative information about radiotherapy plans as compared to other conformity indices. This study advises the users to use the CS3 scale to evaluate a conformal radiotherapy plan which encompasses a wide range of relevant clinical volumes, and is able to extract qualitative dosimetric information.

On the Delineation of the Gross Tumor Volume and Clinical Target Volume for Head and Neck Squamous Cell Carcinomas

Gross tumor volume (GTV) and clinical target volume (CTV) delineation on planning computed tomography (pICT) for head and neck squamous cell carcinomas can be troublesome. We highlight the factors which can be crucial for the radiation oncologist in delineating GTV and CTV on pICT and provide some pratical solutions. Regarding GTV, uncertainties are correlated with transfer of information collected by physical examination and diagnostic radiology to pICT. Moreover, reproducibility of delineation can also be highly variable, particularly when diagnostic imaging quality and pICT quality are poor. Once the prescription has been made, clinical target volume identification on pICT is rarely straightforward. Whereas there are some data about the location of major lymph node stations of the neck, there are no reported guidelines on how to draw subclinical extention of primary head and neck tumors on pICT. Such volumes can be derived from those currently included in simulator films or from those addressed by the surgeon. Some examples are provided. A particular situation is represented by the adjuvant setting, when the primary tumor is removed (by surgery) or reduced (by chemotherapy). In conclusion, this paper shows some major problems associated with identification of GTV and CTV on pICT. Apart from selected cases, the use of pICT for target volume delineation (and thus for field shaping) for head and neck squamous cell carcinoma is still to be considered investigational.

Radiosensitization of Non-Small Cell Lung Cancer Cells by Inhibition of TGF-β1 Signaling With SB431542 Is Dependent on p53 Status

Although medically inoperable patients with stage I non-small cell lung cancer cells (NSCLC) are often treated with stereotactic body radiation therapy, its efficacy can be compromised due to poor radiosensitivity of cancer cells. Inhibition of transforming growth factor-β1 (TGF-β1) using LY364947 and LY2109761 has been demonstrated to radiosensitize cancer cells such as breast cancer, glioblastoma, and lung cancer. Our previous results have demonstrated that another potent and selective inhibitor of TGF-β1 receptor kinases, SB431542, could radiosensitize H460 cells both in vitro and in vivo. In the present study, we investigated whether SB431542 could radiosensitize other NSCLC cell lines, trying to explore the potential implication of this TGF-β1 inhibitor in radiotherapy for NSCLC patients. The results showed that A549 cells were significantly radiosensitized by SB431542, whereas no radiosensitizing effect was observed in H1299 cells. Interestingly, both H460 and A549 cells have wild-type p53, while H1299 cells have deficient p53. To study whether the radiosensitizing effect of SB431542 was associated with p53 status of cancer cells, the p53 of H460 cells was silenced using shRNA transfection. Then it was found that the radiosensitizing effect of SB431542 on H460 cells was not observed in H460 cells with silenced p53. Moreover, X-irradiation caused rapid Smad2 activation in H460 and A549 cells but not in H1299 and H460 cells with silenced p53. The Smad2 activation postirradiation could be abolished by SB431542. This may explain the lack of radiosensitizing effect of SB431542 in H1299 and H460 cells with silenced p53. Thus, we concluded that the radiosensitizing effect of inhibition of TGF-β1 signaling in NSCLC cells by SB431542 was p53 dependent, suggesting that using TGF-β1 inhibitor in radiotherapy may be more complicated than previously thought and may need further investigation.

Role of adjuvant radiotherapy in completely resected non-small-cell lung cancer

Most long-term survivors of non-small-cell lung cancer (NSCLC) are patients who have had a completely resected tumour. However, this is only achievable in about 30% of the patients. Even in this highly selected group of patients, there is still a high risk of both local and distant failure. Adjuvant treatments such as chemotherapy (CT) and radiotherapy (RT) have therefore been evaluated in order to improve their outcome. In patients with stage II and III, administration of adjuvant platinum-based chemotherapy is now considered the standard of care, based on level 1 evidence. The role of postoperative radiation therapy (PORT) remains controversial. In the PORT meta-analysis published in 1998, the conclusions were that if PORT was detrimental to patients with stage I and II completely resected NSCLC, the role of PORT in the treatment of tumours with N2 involvement was unclear and further research was warranted. Thus at present, after complete resection, adjuvant radiotherapy should not be administered in patients with early lung cancer. Recent retrospective and non-randomised studies, as well as subgroup analyses of recent randomised trials evaluating adjuvant chemotherapy, provide evidence of the possible benefit of PORT in patients with mediastinal nodal involvement. The role of PORT needs to be evaluated also for patients with proven N2 disease who undergo neoadjuvant chemotherapy followed by surgery. The risk of local recurrence for N2 patients varies between 20% and 60%. Based on currently available data, PORT should be discussed for fit patients with completely resected NSCLC with N2 nodal involvement, preferably after completion of adjuvant chemotherapy or after surgery if patients have had preoperative chemotherapy. There is a need for new randomised evidence to reassess PORT using modern three-dimensional conformal radiation technique, with attention to normal organ sparing, particularly lung and heart, to reduce the possible over-added toxicity. Quality assurance of radiotherapy as well as quality of surgery – and most particularly nodal exploration modality – should both be monitored. A new large multi-institutional randomised trial Lung ART evaluating PORT in this patient population is needed and is now under way.

Preliminary results of tomotherapy for treatment of inoperable recurrent non-small cell lung cancer at bronchial stump site after right pneumonectomy

Aim of the study

This study aimed to prospectively investigate the clinical outcomes of curative radical helical tomotherapy (HT) applied to recurrent non-small cell lung cancer (NSCLC) at the bronchial stump site after right pneumonectomy. After right pneumonectomy, the heart shifted right laterally. The chambers of the heart closed with a recurrent mass at the bronchial stump were the right atrium and left atrium due to right shifting of the heart. The unfavorable bronchial stump recurrent cancer-heart geometry due to a right shift of the heart might serve as a reliable predictor of cardiac morbidity for aggressive radiotherapy.

Material and methods

The 23 patients received HT for the recurrent NSCLC at the bronchial stump site after right pneumonectomy between 2008 and 2011. The median age of the patients was 65 years (range 56–74).

Results

We prescribed 95% volume of the primary planning target volume (PTV) to a total dose of 69 Gy in 30 fractions, and 95% of the secondary PTV to a total dose of 54 Gy in 30 fractions with reduction of the 50% volume of the heart < 20 Gy. The median conformal index in the 23 plans was 1.21. The mean fraction of primary PTV receiving more than 95% of the prescribed dose was 97.8%. The mean V₄₅, V₅₀, V₆₀ of the heart were 10.5%, 6.5%, 0.2%, respectively. The median follow-up after tomotherapy was 19.86 months. Median survival was 20 months. The 2-year OS was 39.1%.

Conclusions

The relatively high dose tomotherapy alone for patients with a recurrent bronchial stump mass which was proximal to the heart demonstrated favorable clinical results without severe heart or pulmonary complications.

Comparative effectiveness research in radiation oncology: assessing technology

Technological advances are a major contributor to rising costs in health care, including radiation oncology. Despite the large amount spent on new technologies, technology assessment remains inadequate, leading to potentially costly and unnecessary use of new technologies. Comparative effectiveness studies have an important role to play in evaluating the benefits and harms of new technologies compared with older technologies and have been identified as a priority area for research by the Radiation Oncology Institute. This article outlines the elements of effective technology assessment, identifies key challenges to comparative effectiveness studies of new radiation oncology technologies, and reviews several examples of comparative effectiveness studies in radiation oncology, including studies on conformal radiation, IMRT, proton therapy, and other concurrent new technologies.

Reinforcing of QA/QC programs in radiotherapy departments in Croatia: results of treatment planning system verification

Implementation of advanced techniques in clinical practice can greatly improve the outcome of radiation therapy, but it also makes the process much more complex with a lot of room for errors. An important part of the quality assurance program is verification of treatment planning system (TPS). Dosimetric verifications in anthropomorphic phantom were performed in 4 centers where new systems were installed. A total of 14 tests for 2 photon energies and multigrid superposition algorithms were conducted using the CMS XiO TPS. Evaluation criteria as specified in the International Atomic Energy Agency Technical Reports Series (IAEA TRS) 430 were employed. Results of measurements are grouped according to the placement of the measuring point and the beam energy. The majority of differences between calculated and measured doses in the water-equivalent part of the phantom were in tolerance. Significantly more out-of-tolerance values were observed in "nonwater-equivalent" parts of the phantom, especially for higher-energy photon beams. This survey was done as a part of continuous effort to build up awareness of quality assurance/quality control (QA/QC) importance in the Croatian radiotherapy community. Understanding the limitations of different parts of the various systems used in radiation therapy can systematically improve quality as well.

Dosimetric comparison of free-breathing and deep inspiration breath-hold radiotherapy for lung cancer

PURPOSE

The goal of this work was to evaluate the potential benefit of deep inspiration breath-hold (DIBH) compared to free breathing (FB) radiotherapy in a homogeneous population of patients with lung cancer.

METHODS AND MATERIALS

A total of 25 patients with non-small cell lung cancer treated by DIBH underwent an additional FB CT scan. The DIBH and FB treatment plans were compared. Target volume was compared using coverage, homogeneity, and conformal indices. Organs at risk were compared using V(5), V(13), V(20), V(25), V(37), mean dose (D(mean)) for lungs, V(40) and D(mean) for the heart, V(50), D(mean) and maximum dose (D(max)) for the esophagus, and using biological indices, i.e., the equivalent uniform dose (EUD) and the normal tissue complication probability (NTCP).

RESULTS

Median age was 62 years. Prescribed total dose was 66 Gy. Conformity index was improved with DIBH (0.67 vs. 0.58, p = 0.046) but coverage and homogeneity indices were not significantly different. Lung dosimetric parameters were improved using DIBH: D(mean) (13 vs. 15 Gy, p = 10(-4)), V(5) (43 vs. 51%, p = 6.10(-5)), V(13) (31 vs. 38%, p = 2.10(-3)), V(20) (25 vs. 31%, p = 0.01), V(25) (22% vs. 27%, p = 0.01) and V(37) (12 vs. 16%, p = 0.03), EUD (8.2 vs. 9.9 Gy, p = 3.10(-4)), and NTCP (1.9 vs. 4.8%, p = 10(-3)). For the heart, D(mean) (14 vs. 17 Gy, p = 0.003), V(40) (12 vs. 17%, p = 0.004), and EUD (19 vs. 22 Gy, p = 6.10(-4)) were reduced with DIBH, whereas V(30) and NTCP were similar. DIBH improved the D(mean) (28 vs. 30 Gy, p = 0.007) and V(50) (25 vs. 30%, p = 0.003) for the esophagus, while EUD, NTCP, and D(max) were not altered.

CONCLUSION

DIBH improves the target conformity index and heart and lung dosimetry in lung cancer patients treated with radiotherapy. The clinical implications of these findings should be confirmed.

Optimal radiotherapy for non-small-cell lung cancer: current progress and future challenges

Radiotherapy has a key role in treating lung cancer. Advances in physics and computer technology have improved radiation delivery systems. With innovations in the radiation therapy of non-small-cell lung cancer (NSCLC), new strategies have emerged, such as intensity-modulated radiation therapy, stereotactic body radiation therapy, and particle therapy. Compared with previous methods, these newer technologies can deliver even higher doses precisely to the tumor while minimizing doses to normal tissues, which should lead to better tumor control with less toxicity. In patients with stage I NSCLC, stereotactic body radiation therapy is highly effective and may achieve local control and survival equivalent to that achieved with surgery. In patients with stage III NSCLC, dose escalation has been investigated using three-dimensional conformal radiation therapy, intensity-modulated radiation therapy, and particle therapy. The results from ongoing randomized trials on both patient populations are awaited. It is important to generate new hypotheses and to explore newer radiotherapy approaches to overcome NSCLC.

Lung abnormalities at multimodality imaging after radiation therapy for non-small cell lung cancer

Three-dimensional (3D) conformal radiation therapy (CRT) and stereotactic body radiation therapy (SBRT) are designed to deliver the maximum therapeutic radiation dose to the tumor, allowing improved local disease control, while minimizing irradiation of surrounding normal structures. The complex configuration of the multiple beams that deliver the radiation dose to the tumor in 3D CRT and SBRT produces patterns of lung injury that differ in location and extent from those seen after conventional radiation therapy. Radiation-induced changes in lung tissue after 3D CRT and SBRT occur within the radiation portals. The imaging appearance of irradiated tissues varies according to the time elapsed after the completion of therapy, with acute-phase changes of radiation pneumonitis represented by ground-glass opacities and consolidation and with late-phase changes of radiation fibrosis manifesting as volume loss, consolidation, and traction bronchiectasis. Knowledge of treatment timelines and radiation field locations, as well as familiarity with the full spectrum of possible radiation-induced lung injuries after 3D CRT and SBRT, is important to correctly interpret the abnormalities that may be seen at computed tomography (CT). Differential diagnoses in this context might include infections, lymphangitic carcinomatosis, local recurrence of malignancy, and radiation-induced tumors. The integration of morphologic information obtained at CT with metabolic information obtained at positron emission tomography is helpful in distinguishing radiation-induced parenchymal abnormalities from residual, recurrent, and new cancers. Thus, multimodality follow-up imaging may lead to substantial changes in disease management.

Role of postoperative radiotherapy in resected non-small cell lung cancer: a reassessment based on new data

In completely resected non-small cell lung cancer (NSCLC) patients with pathologically involved mediastinal lymph nodes (N2), administration of adjuvant platinum-based chemotherapy is now considered the standard of care, based on level 1 evidence. The role of postoperative radiation therapy (PORT) in this group of patients remains controversial. The PORT meta-analysis published in 1998 concluded that adjuvant radiotherapy was detrimental to patients with early-stage completely resected NSCLC, but that the role of PORT in the treatment of tumors with N2 involvement was unclear, and that further research was warranted. Recent retrospective and nonrandomized studies, as well as subgroup analyses of recent randomized trials evaluating adjuvant chemotherapy, provide evidence of the possible benefit of PORT in patients with mediastinal nodal involvement. The role of PORT is also a valid question in patients with proven N2 disease who have undergone only induction chemotherapy followed by surgery, because the local recurrence rate for such patients varies in the range of 20%-60%. Based on the currently available data, PORT should be discussed for fit patients with completely resected NSCLC with N2 nodal involvement, preferably after completion of adjuvant chemotherapy. There is a need for new randomized evidence to evaluate PORT using the modern three-dimensional conformal radiation technique, with attention paid to reducing the risk for, particularly, pulmonary and cardiac toxicity. A new large multi-institutional randomized trial evaluating PORT in this patient population is needed and now under way.

Effect of radiotherapy planning complexity on survival of elderly patients with unresected localized lung cancer

PURPOSE

To evaluate whether complex radiotherapy (RT) planning was associated with improved outcomes in a cohort of elderly patients with unresected Stage I-II non-small-cell lung cancer (NSCLC).

METHODS AND MATERIALS

Using the Surveillance, Epidemiology, and End Results registry linked to Medicare claims, we identified 1998 patients aged >65 years with histologically confirmed, unresected stage I-II NSCLC. Patients were classified into an intermediate or complex RT planning group using Medicare physician codes. To address potential selection bias, we used propensity score modeling. Survival of patients who received intermediate and complex simulation was compared using Cox regression models adjusting for propensity scores and in a stratified and matched analysis according to propensity scores.

RESULTS

Overall, 25% of patients received complex RT planning. Complex RT planning was associated with better overall (hazard ratio 0.84; 95% confidence interval, 0.75-0.95) and lung cancer-specific (hazard ratio 0.81; 95% confidence interval, 0.71-0.93) survival after controlling for propensity scores. Similarly, stratified and matched analyses showed better overall and lung cancer-specific survival of patients treated with complex RT planning.

CONCLUSIONS

The use of complex RT planning is associated with improved survival among elderly patients with unresected Stage I-II NSCLC. These findings should be validated in prospective randomized controlled trials.

Radiotherapy Planning Complexity and Survival after Treatment of Advanced Stage Lung Cancer in the Elderly

PURPOSE: Complex radiotherapy (RT) planning is increasingly common in the treatment of lung cancer though it remains unclear if these treatments are associated with better outcomes. We evaluated the association between the complexity of RT planning simulation with survival among elderly Stage IIIB non-small cell lung cancer (NSCLC) patients. METHODS: We included all patients aged >65 years with histologically confirmed Stage IIIB NSCLC diagnosed between 1992 and 2002 receiving chemotherapy and RT from the Surveillance, Epidemiology, and End Results registry linked to Medicare claims. Patients were divided into simple, intermediate, and complex RT planning groups using Medicare physician codes. Kaplan-Meier curves and Cox regression were used to compare overall and lung cancer-specific survival rates across groups. RESULTS: We identified 1,733 patients: 148 (8%), 1,138 (66%), and 447 (26%) were classified as having received simple, intermediate and complex RT planning, respectively. Baseline characteristics were similar across groups. Increasing complexity of RT planning was significantly associated with better overall survival (p=0.0002). Multivariate analyses showed that intermediate (HR: 0.75, 95% CI: 0.62 to 0.91) and complex planning (HR: 0.69, 95% CI: 0.55 to 0.86) were associated with better overall survival compared to simple RT planning. Similar results were observed for lung cancer-specific survival analyses. Toxicities were comparable across groups. CONCLUSIONS: The use of more complex RT planning and simulation methods is associated with better survival in elderly patients with Stage IIIB NSCLC. Although these results should be further validated in prospective clinical trials, this data suggests that complex planning may improve the outcomes of these patients.

Comparação entre os volumes pulmonares irradiados com técnica bidimensional e tridimensional conformada na radioterapia de pacientes com tumores de pulmão localmente avançados

OBJETIVO: Comparar e quantificar os volumes pulmonares irradiados utilizando planejamentos bidimensional (2D) e tridimensional (3D) conformado na radioterapia de tumores de pulmão. MATERIAIS E MÉTODOS: Em 27 pacientes portadores de câncer de pulmão foi feito planejamento 3D e outro correspondente em 2D. As doses prescritas variaram de 45 a 66 Gy. Foram avaliadas as doses no volume alvo planejado (PTV), volume tumoral macroscópico (GTV) e pulmões (volume de pulmão que recebe 20 Gy ou 30 Gy - V20 e V30, respectivamente, e dose média). Os órgãos de risco adjacentes (medula espinhal, esôfago e coração) receberam doses abaixo dos limites de tolerância. RESULTADOS: O GTV variou de 10,5 a 1.290,0 cm³ (média de 189,65 cm³). Nos planejamentos 2D foi utilizado, em média, um total de 59,33 campos, e nos planejamentos 3D, 75,65 campos. Em todas as situações analisadas houve significante (p < 0,05) preservação dos volumes pulmonares com o planejamento 3D, com diminuição de cerca de 15% dos volumes irradiados. O pulmão sem tumor foi mais beneficiado. CONCLUSÃO: A radioterapia 3D permitiu maior preservação dos pulmões, tanto para tumores iniciais quanto avançados. A radioterapia 3D deve ser utilizada nos pacientes com tumores de pulmão, mesmo que volumosos.

Prediction of radiation pneumonitis following high-dose thoracic radiation therapy by 3 Gy/fraction for non-small cell lung cancer: analysis of clinical and dosimetric factors

OBJECTIVE

This study was undertaken to identify the factors predictive of radiation pneumonitis (RP) in 69 non-small cell lung cancer patients treated with thoracic radiation therapy only by 3 Gy fractions.

METHODS

A total of 69 patients who received only RT in daily 3 Gy were included in this study. Grade > or =3 RP was defined as an RP event. The cumulative incidence of RP was estimated and the correlations of the development of RP with the potential predictors were determined.

RESULTS

The cumulative incidence of events was 17.1% at 12 months. By univariate analysis, all clinical factors [age, performance status, weight loss, pre-RT forced expiratory volume in 1 s, tumour location, stage, RT dose and clinical target volume] were not associated with the risk of Grade > or =3 RP; however, all dosimetric factors [V5-50 and mean lung dose (MLD)] closely correlated with the development of RP. The receiver-operative characteristics (ROC) analysis revealed that MLD was the best predictors of Grade > or =3 RP (area under curve ROC = 0.937). By multivariate analysis, MLD was the only significant factor to be predictive of RP risk: the probability of Grade > or =3 RP was 3.7% when MLD < or = 16.1 Gy and 78.4% when MLD > 16.1 Gy.

CONCLUSIONS

Dosimetric parameters were valuable in predicting the development of RP.

A treatment planning comparison of combined photon-proton beams versus proton beams-only for the treatment of skull base tumors

PURPOSE

To compare treatment planning between combined photon-proton planning (CP) and proton planning (PP) for skull base tumors, so as to assess the potential limitations of CP for these tumors.

METHODS AND MATERIALS

Plans for 10 patients were computed for both CP and PP. Prescribed dose was 67 cobalt Gray equivalent (CGE) for PP; 45 Gy (photons) and 22 CGE (protons) for CP. Dose-volume histograms (DVHs) were calculated for gross target volume (GTV), clinical target volume (CTV), normal tissues (NT), and organs at risk (OARs) for each plan. Results were analyzed using DVH parameters, inhomogeneity coefficient (IC), and conformity index (CI).

RESULTS

Mean doses delivered to the GTVs and CTVs with CP (65.0 and 61.7 CGE) and PP (65.3 and 62.2 Gy CGE) were not significantly different (p > 0.1 and p = 0.72). However, the dose inhomogeneity was drastically increased with CP, with a mean significant incremental IC value of 10.5% and CP of 6.8%, for both the GTV (p = 0.01) and CTV (p = 0.04), respectively. The CI(80%) values for the GTV and CTV were significantly higher with PP compared with CP. Compared with CP, the use of protons only led to a significant reduction of NT and OAR irradiation, in the intermediate-to-low dose (< or =80% isodose line) range.

CONCLUSIONS

These results suggest that the use of CP results in levels of target dose conformation similar to those with PP. Use of PP significantly reduced the tumor dose inhomogeneity and the delivered intermediate-to-low dose to NT and OARs, leading us to conclude that this treatment is mainly appropriate for tumors in children.

Exceptionally high incidence of symptomatic grade 2-5 radiation pneumonitis after stereotactic radiation therapy for lung tumors

BACKGROUND

To determine the usefulness of dose volume histogram (DVH) factors for predicting the occurrence of radiation pneumonitis (RP) after application of stereotactic radiation therapy (SRT) for lung tumors, DVH factors were measured before irradiation.

METHODS

From May 2004 to April 2006, 25 patients were treated with SRT at the University of Tokyo Hospital. Eighteen patients had primary lung cancer and seven had metastatic lung cancer. SRT was given in 6-7 fields with an isocenter dose of 48 Gy in four fractions over 5-8 days by linear accelerator.

RESULTS

Seven of the 25 patients suffered from RP of symptomatic grade 2-5 according to the NCI-CTC version 3.0. The overall incidence rate of RP grade2 or more was 29% at 18 months after completing SRT and three patients died from RP. RP occurred at significantly increased frequencies in patients with higher conformity index (CI) (p = 0.0394). Mean lung dose (MLD) showed a significant correlation with V5-V20 (irradiated lung volume) (p < 0.001) but showed no correlation with CI. RP did not statistically correlate with MLD. MLD had the strongest correlation with V5.

CONCLUSION

Even in SRT, when large volumes of lung parenchyma are irradiated to such high doses as the minimum dose within planning target volume, the incidence of lung toxicity can become high.

Conformity index: a review

We present a critical analysis of the conformity indices described in the literature and an evaluation of their field of application. Three-dimensional conformal radiotherapy, with or without intensity modulation, is based on medical imaging techniques, three-dimensional dosimetry software, compression accessories, and verification procedures. It consists of delineating target volumes and critical healthy tissues to select the best combination of beams. This approach allows better adaptation of the isodose to the tumor volume, while limiting irradiation of healthy tissues. Tools must be developed to evaluate the quality of proposed treatment plans. Dosimetry software provides the dose distribution in each CT section and dose-volume histograms without really indicating the degree of conformity. The conformity index is a complementary tool that attributes a score to a treatment plan or that can compare several treatment plans for the same patient. The future of conformal index in everyday practice therefore remains unclear.

Phase II study of radiotherapy with three-dimensional conformal boost concurrent with paclitaxel and cisplatin for Stage IIIB non–small-cell lung cancer

PURPOSE

To evaluate the efficacy and toxicity of concurrent chemoradiotherapy with paclitaxel/cisplatin for Stage IIIB locally advanced non-small-cell lung cancer (NSCLC).

METHODS AND MATERIALS

Radiotherapy was administered to a total dose of 70.2 Gy (daily fraction of 1.8 Gy, 5 days/wk), over an 8-week period, combined with chemotherapy. The chemotherapy consisted of weekly 40 mg/m2 of paclitaxel plus 20 mg/m2 of cisplatin for 8 consecutive weeks. All patients received three-dimensional conformal radiotherapy (3D-CRT), based on computed tomography simulated planning after 41.4 Gy. The median follow-up period of survivors was 24 months.

RESULTS

Between January 2000 and October 2002, 135 patients with a median age of 60 years were enrolled and analyzed in this prospective trial. The overall response rate was 75% including 2 cases of complete response. The major patterns of failure were local failure and distant metastasis. The 2-year overall and progression-free survival rates were 37% and 18%, respectively. The median overall and progression-free survival times were 17 months and 9 months, respectively. Hematologic toxicity >Grade 2 was observed in 19% of patients and severe non-hematologic toxicity was infrequent.

CONCLUSIONS

Three-dimensional conformal radiotherapy, combined with paclitaxel and cisplatin chemotherapy, was associated with a satisfactory outcome with manageable toxicity. Further investigations are needed to improve the local control.

Comparison of two dimensional and three dimensional radiotherapy treatment planning in locally advanced non-small cell lung cancer treated with continuous hyperfractionated accelerated radiotherapy weekend less

BACKGROUND AND PURPOSE

Patients with inoperable non-small cell lung cancer being treated with continuous hyperfractionated accelerated radiotherapy weekend less (CHARTWEL) were planned and treated with a three dimensional (3D) conformal protocol and comparison made with two dimensional (2D) planning, as used previously, to compare past practice and methods.

PATIENTS AND METHODS

Twenty-four patients were planned initially using 3D and then replanned using a 2D system. The 2D plans were transferred onto the 3D system and recalculated. Dose volume histograms could then be constructed of planning target volumes for phases 1 and 2 (PTV 1 and 2, respectively), lung and spinal cord for the 2D plans and compared with the 3D plans.

RESULTS

There was a significantly lower absolute dose to the isocentre with 2D compared to 3D planning with dose reductions of 3.9% for phase 1, 4.4% for phase 2 and 4.7% for those treated with a single phase. Maximum dose to spinal cord was greater in 17 of the 24 2D plans with a median dose reduction of 0.82 Gy for 3D (P=0.04). The percentage volume of whole lung receiving > or =20 Gy (V20) was greater in 16 of the 24 2D plans with a median reduction in V20 of 2.4% for 3D (P=0.03).

CONCLUSIONS

A lower dose to tumour was obtained using 2D planning due to the method of dose calculation and spinal cord and lung doses were significantly higher.

CT-planned accelerated hypofractionated radiotherapy in the radical treatment of non-small cell lung cancer

Surgery is the standard treatment for stage I, II and certain stage IIIA non-small cell lung cancers (NSCLC). A proportion of patients with technically operable NSCLC do not undergo surgery because of significant co-morbidity or refusal, and radical radiotherapy may cure some of these patients. Between April 1997 and March 2000, 135 consecutive patients with stage I-IIIB NSCLC were treated with CT-planned accelerated hypofractionated radical radiotherapy to a dose of 50-55Gy in 15-20 fractions over 3-4 weeks at a single centre. The 2-year overall and cause-specific survival for all patients was 44.4% (95% CI = 36.8, 53.7) and 47.8% (95% CI = 39.9, 57.3) respectively. Overall median survival was 21 months (95% 18, 28). There were no reports of severe acute or late treatment-related toxicities. These results compare favourably with previously published studies on radical radiotherapy in NSCLC, suggesting this may be an effective and safe technique.

[Conformal index and radiotherapy]

Goal of radiotherapy is to treat patient with the best therapeutic ratio, i.e. the highest local control and the lowest toxicity rates. The conformal approach, three-dimensional conformal radiotherapy or intensity-modulated radiotherapy, is based on imageries, up-dated 3-D treatment planning systems, immobilization systems, restricted quality assurance and treatment verification. The aim is to ensure a high dose distribution tailored to the limits of the target volume, while reducing exposure of normal tissues. The evaluation tools used for optimizing treatment are the visual inspection of the dose distribution in various planes, and the dose-volume histograms, but they do not fully quantify the conformity of dose distributions. The conformal index is a tool for scoring a given plan or for evaluating different treatment plans for the same patient. This paper describes the onset and evolution of conformal index and his potential application field.

[New radiotherapy techniques for non-small-cell lung cancer]

Lung cancer is one of the most difficult challenges for radiotherapy. Problems include ballistic targeting compromised by respiratory movements, poor tolerance of neighboring healthy tissues and difficult dosimetry due to the heterogeneous nature of the thoracic tIssues. New perspectives are offered by recent developments allowing a more comprehensive approach to thoracic radiotherapy integrating new advances in imaging techniques, contention, dosimetry, and treatment devices. Two techniques are particularly promising: conformal radiotherapy and respiration-gated radiotherapy. Conformal radiotherapy, a three-dimensional conformal mode of irradiation with or without intensity modulation, is designed to achieve high-precision dose delivery by integrating advanced imaging techniques into the irradiation protocol. These tools are used to optimize irradiation of target Volumes and avoid recurrence while sparing as much as possible healthy tissues. If healthy tissue can be correctly protected, increased doses can be delivered to the target tumor. Respiration-gated techniques offer promising prospects for the treatment of tumors which are displaced by respiratory movements. These techniques allow better adaptation of the irradiation fields to the target tumor and better protection of healthy tissues (lung, heart...). These new approaches are now routine practices in many centers. Early results have been very promising. We describe here the currently available techniques for thoracic radiotherapy.

Resected non-small cell lung cancer: need for adjuvant lymph node treatment? From hope to reality

Even if postoperative thoracic radiotherapy has been widely used as adjuvant treatment, the oncological community has poorly evaluated this treatment after complete surgical resection in lung cancer. The number of patients included in randomised trials has been less than 3000. The analysis of these trials showed rather a deleterious effect in terms of overall survival, suggesting a lethal late treatment-related toxicity in early stage I or II disease. In N2 disease, these effects have not been demonstrated but information is lacking to consider this treatment on an evidence-based medicine policy. We discuss here the available worldwide information on this subject. There is an urgent need for new trials in this topic.

Image-guided conformal radiation therapy planning and delivery for non-small-cell lung cancer

BACKGROUND

Our understanding of both the importance of local control for survival of patients with unresectable lung cancer and the inadequacy of conventional radiation therapy (RT) to provide this local control has undergone marked changes in the past 2 decades.

METHODS

A review was conducted of recent studies and meta-analyses in the literature that have convincingly demonstrated the value of thoracic irradiation in increasing long-term survival in patients with both small-cell lung cancer and non-small-cell lung cancer (NSCLC).

RESULTS

Large cooperative trials have shown long-term local control of only approximately 10% for NSCLC using conventionally planned radiation to doses of 60-64 Gy either as a single modality or when preceded by induction chemotherapy. Concurrent chemotherapy may modestly improve local control at the cost of greater acute esophageal toxicity. Simple escalation of radiation dose is limited by the tolerance of normal intrathoracic organs. Recent developments in anatomic and functional imaging, computerized RT planning, and RT delivery, as well as a reassessment of the appropriate target volumes for RT in the context of combined modality therapy, provide the capability to better conform regions of high dose to the target volume and test the hypothesis that increases in tumor dose will improve local control and survival.

CONCLUSIONS

Encouraging phase II data have been reported from single institutions using individually developed software and hardware. The availability of commercial tools for planning and delivering such conformal treatment will allow prospective assessment of the true value of these technologies in the management of patients with lung cancer.

Analysis of dose distribution in the 'Rind'--a volume outside the PTV--in 3-dimensional conformal radiation therapy of non-small cell lung cancer

BACKGROUND AND PURPOSE

Appropriate planning target volume (PTV) definition is critical for local disease eradication in the treatment of non-small cell lung cancer (NSCLC). When margins are added to the gross tumour volume (GTV) in the standard way, the PTV formed may be too large to facilitate dose escalation due to normal tissue tolerance. To increase the feasibility of dose escalation with 3-dimensional conformal radiotherapy (3DCRT), this study examines an alternative method for the formation of the PTV in NSCLC. This strategy is based on the reduced probability of tumour cells from the GTV outwards and on the associated lower dose requirements to eradicate such subclinical disease.

MATERIALS AND METHODS

3DCRT plans were generated from the CT scans of 15 patients with NSCLC (stages Ib to IIIb). Each PTV was formed by adding a margin for geometric uncertainties directly onto the GTV. The success of this approach is dependent on the volume immediately outside this smaller PTV, the Rind volume, receiving 50 Gy, the minimum dose requirement that is considered sufficient for eradication of the reduced tumour cell density in this volume. While optimizing the treatment plans for each PTV to 70 Gy, the dose distribution in the Rind volume, and the factors affecting it, were assessed.

RESULTS

One hundred percent of each PTV received a minimum of 95% of the prescribed dose. The percentage of the Rind volume receiving 50 Gy or more (V50) had a median value of 94%. The minimum dose in this volume, however, ranged from 5.6 to 32.1 Gy. The V50 was highest for apical tumours (96.1%) and lowest for peripheral tumours (86%) and correlated positively with the size of the PTV (Kendall's rank correlation (Kt)=+0.3, P=0.05) and the number of beams used (Kt=+0.3, P=0.03) but not with the conformity index. The average volume outside the Rind which still received >/=50 Gy (the Wasted 50 Gy) increased significantly with the V50 of the Rind volume and was inversely proportional to the Rind <50 Gy, correlating significantly with the dose to the organs at risk.

CONCLUSIONS

Using this strategy with standard 3DCRT, all PTVs were irradiated to the required dose with this approach, but none of the corresponding Rind volumes had an acceptable dose distribution. The addition of dual volume planning or the use of intensity modulated radiation therapy may achieve an appropriate dose distribution in the Rind volume while not increasing the dose to the organs at risk and may thereby facilitate dose escalation.

[Non-small-cell bronchial cancers: improvement of survival probability by conformal radiotherapy]

The conformal radiotherapy approach, three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT), is based on modern imaging modalities, efficient 3D treatment planning systems, sophisticated immobilization devices and demanding quality assurance and treatment verification. The main goal of conformal radiotherapy is to ensure a high dose distribution tailored to the limits of the target volume while reducing exposure of healthy tissues. These techniques would then allow a further dose escalation increasing local control and survival. Non-small cell lung cancer (NSCLC) is one of the most difficult malignant tumors to be treated. It combines geometrical difficulties due to respiratory motion, and number of low tolerance neighboring organs, and dosimetric difficulties because of the presence of huge inhomogeneities. This localization is an attractive and ambitious example for the evaluation of new techniques. However, the published clinical reports in the last years described very heterogeneous techniques and, in the absence of prospective randomized trials, it is somewhat difficult at present to evaluate the real benefits drawn from those conformal radiotherapy techniques. After reviewing the rationale for 3DCRT for NSCLC, this paper will describe the main studies of 3DCRT, in order to evaluate its impact on lung cancer treatment. Then, the current state-of-the-art of IMRT and the last technical and therapeutic innovations in NSCLC will be discussed.

Dose-intensified accelerated vindesine-ifosfamide-cisplatin (VIP) chemotherapy followed by high-dose accelerated hyperfractionated radiotherapy in patients with pathologically proven stage IIIB non-small cell lung cancer: a feasibility study

This study shows the feasibility of accelerated vindesine-ifosfamide-cisplatin chemotherapy, immediately followed by intensive radiotherapy to the residual tumour in responding patients, in 16 patients with pathologically proven stage IIIB non-small lung cancer. All toxicities were reversible, with only two of ten patients experiencing grade 3 oesophagitis, no treatment-related deaths and no serious late effects.

Radiosensitization with chemotherapeutic agents

The combination of low-dose chemotherapy and thoracic radiotherapy is one of the treatments proposed in an attempt to improve the prognosis of locally advanced non-small cell lung cancer. Chemotherapeutic drugs administered at subtoxic doses act by means of a radiosensitization mechanism. Platinum-derived drugs have been historically used as radiosensitizers, without cumulative unacceptable toxicity. Many new chemotherapeutic agents, which have shown promising results in terms of disease control in advanced non-small cell lung cancer, show also a radiosensitizing activity. However, the optimal dose and timing of such drugs when used concurrently to radiotherapy are unknown. This paper will review the results obtained using new chemotherapeutic drugs as radiosensitizers.

Dose and fractionation concepts in the primary radiotherapy of non-small cell lung cancer

At present, radiotherapy alone or in combination with chemotherapy offers the only chance of cure of medically inoperable or locally advanced unresectable non-small cell lung cancer. The radiobiological basis and clinical results of current dose and fractionation concepts in the primary radiotherapy of NSCLC are briefly reviewed. Whenever possible, focus is given to the results of randomized phase III trials. With the exception of early disease treated to doses higher than 60 Gy, the prognosis of inoperable localized NSCLC is very poor. Local recurrence is the major cause of failure after radiation therapy calling for intensified local treatment. Dose-escalation using conventional fractionation or moderate hypofractionation is promising but randomized trials are presently not available. Dose-escalated hyperfractionation theoretically offers advantages, however, there appears currently no strong evidence from randomized trials supporting this approach in NSCLC. The highly accelerated CHART regimen significantly improved survival by 9% compared to standard radiotherapy. Nevertheless, even when treated with CHART, about 80% of all patients will eventually develop local recurrence and 60% distant metastases. Many trials on combined radiochemotherapy have used radiotherapy regimens that are not optimal from a current perspective. Because of the high rate of both, local recurrence and distant metastases, future research should be directed to further intensify radiotherapy as well as to integrate such protocols with systemic treatment in carefully selected patients. Since toxicity is expected to increase, state-of-the-art 3D conformal radiation techniques need to be part of clinical trials testing such strategies.