Conformal radiotherapy of non-small-cell lung cancer]

About one third of lung cancers initially present with a localised disease, without any curative surgery potential, because of local spread or comorbidity. Definitive radiation, alone or combined with chemotherapy, then represents the treatment of choice for these patients. The results, however, are disappointing, with a biopsy-proven local control of 10% at two years and a 5-10% five-year survival rate. These poor results may be partially explained by the difficulties in delineating the tumour volume as well as the dose limitations due to poor tolerance of surrounding normal organs. Lung parenchyma sequelae remain daily worrying events for the oncologist. The advent of 3D conformal radiation therapy (3DRT) allows progress and innovations, including the use of modern imaging techniques, sophisticated dosimetry and treatment planning, efficient immobilisation devices and on-line verification procedures. With more precise (and time-consuming) procedures, 3DRT will allow a better tumour volume delineation, an increased tumour dose and a dose limitation in normal tissues. These improvements may help increase local control and survival results. 3DRT, which has been used for several years for prostate cancer and benefits from recent imaging improvements, will now allow treatment of other locations, such as lung cancer, with conformal therapy. The few preliminary results are encouraging. This work reviews the current data and remaining questions regarding lung cancer treated with 3DRT, and presents and discusses the literature before discussing future trends in this area.     

Conformal radiotherapy: tomotherapy]

Conformal radiation therapy allows the possibility of delivering high doses at the tumor volume whilst limiting the dose to the surrounding tissues and diminishing the secondary effects. With the example of the conformal radiation therapy used at the AZ VUB (3DCRT and tomotherapy), two treatment plans of a left ethmoid carcinoma will be evaluated and discussed in detail. The treatment of ethmoid cancer is technically difficult for both radiation therapy and surgery because of the anatomic constraints and patterns of local spread. A radiation therapy is scheduled to be delivered after surgical resection of the tumor. The treatment plan for the radiation therapy was calculated on a three-dimensional (3D) treatment planning system based on virtual simulation with a beam's eye view: George Sherouse's Gratis. An effort was made to make the plan as conformal and as homogeneous as possible to deliver a dose of 66 Gy in 33 fractions at the tumor bed with a maximum dose of 56 Gy to the right optic nerve and the chiasma. To establish the clinical utility and potential advantages of tomotherapy over 3DCRT for ethmoid carcinoma, the treatment of this patient was also planned with Peacock Plan. For both treatment plans the isodose distributions and cumulative dose volume histograms (CDVH) were computed. Superimposing the CDVHs yielded similar curves for the target and an obvious improvement for organs at risk such as the chiasma, brainstem and the left eye when applying tomotherapy. These results have also been reflected in the tumor control probabilities (equal for both plans) and the normal tissue complication probabilities (NTCP), yielded significant reductions in NTCP for tomotherapy. The probability of uncomplicated tumor control was 52.7% for tomotherapy against 38.3% for 3DCRT.     

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.     

Conformal radiotherapy in cancer of the upper aerodigestive tract]

The outcome of head and neck malignancies is closely related to the achievement of local tumor control. The occurrence of severe late complications is the consequence of the anatomic vicinity between dose-limiting normal tissues and the tumor, thus reducing the curative potential of radiotherapy. Conformal radiotherapy is presently actively investigated as a way to improve the dose distribution in head and neck malignancies (especially when originating from the nasopharynx or the sinuses) while protecting healthy organs. Such an approach requires a chain of sophisticated procedures, including efficient quality assurance programs, in order to achieve the proper degree of safety. The relatively limited clinical studies published to-date have already confirmed the advantage of conformal radiotherapy in terms of dose delivery. The development of beam intensity modulation is likely to further contribute to the improvement of the therapeutic ratio.     

Conformal radiotherapy of brain tumors]

Conformal irradiation of brain tumours is based on the three-dimensional reconstruction of the targeted volumes and at-risk organ images, the three-dimensional calculation of the dose distribution and a treatment device (immobilisation, beam energy, collimation, etc.) adapted to the high precision required by the procedure. Each step requires an appropriate methodology and a quality insurance program. Specific difficulties in brain tumour management are related to GTV and CTV definition depending upon the histological type, the quality of the surgical resection and the medical team. Clinical studies have reported dose escalation trials, mostly in high-grade gliomas and tumours at the base of the skull. Clinical data are now providing a better knowledge of the tolerance of normal tissues. As for small tumours, the implementation of beam intensity modulation is likely to narrow the gap between conformal and stereotaxic radiotherapy.     

Conformal radiotherapy of urinary bladder cancer.

Recent advances in radiotherapy (RT) are founded on the enhanced tumour visualisation capabilities of new imaging modalities and the precise deposition of individualised radiation dose distributions made possible with the new systems for RT planning and delivery. These techniques have a large potential to also improve the results of RT of urinary bladder cancer. Major challenges to take full advantage of these advances in the management of bladder cancer are to control, and, as far as possible, reduce bladder motion, and to reliably account for the related intestine and rectum motion. If these obstacles are overcome, it should be possible in the near future to offer selected patients with muscle invading bladder cancer an organ-sparing, yet effective combined-modality treatment as an alternative to radical surgery.     

Conformal and intensity-modulated radiotherapy for cervical cancer

Three-dimensional radiotherapy planning techniques, including conformal radiotherapy and intensity-modulated radiotherapy, have potential for improving outcomes in cervical cancer. Accurate target volume definition is essential in order to maximise normal tissue sparing while minimising the risk of a geographical miss. This reduction in toxicity provides the option of dose escalation, particularly with simultaneous integrated boost intensity-modulated radiotherapy. The evidence for the current use and potential applications of these techniques in the treatment of cervical cancer are discussed.     

Conformal radiotherapy planning for lung cancer: analysis of set-up uncertainties

The objective of this study was to evaluate set-up uncertainties using a portal imaging system in a population of inoperable non-small cell lung cancer. Twenty-one patients were treated by a conformal radiotherapy technique with a personalized immobilization cast. The beam was verified by comparison with a corresponding digitally reconstructed radiograph by superimposition of anatomical structures. One thousand eight hundred eighty three images were analyzed. The mean intrafraction and interfraction errors (±SD) were 2.17 mm and 0.9 ± 3.7 mm, 2.3 mm and 0.9 ± 3.1 mm, 3 mm and 0.7 ± 3 mm on the lateral (x), cranio-caudal (y) and anterior-posterior (z) axes, respectively. The mean systematic error was small, less than 1 mm, in all directions. The random errors were 2.5 mm, 2.4 mm, and 1.8 mm on the x, y, and z axes, respectively. No correlation between errors and the patient's height, weight, age, or sex was found. Set-up errors accuracy depending on practices, each institution should review their own treatments to quantify and reduce set-up errors in clinical practice.     

Conformal radiotherapy in prostate cancer: for whom and how?]

External radiotherapy is one of the modalities used to cure localized prostate carcinoma. Most of localized prostate carcinomas, specially those of the intermediate prognostic group, may benefit from escalated dose above 70 Gy at least as regard biochemical and clinical relapse free survival. 3D-CRT allows a reduction of the dose received by organs at risk and an increase of prostate dose over 70 Gy. It is on the way to become a standard. Intensity modulated radiation therapy increases dose homogeneity and reduces rectal dose. These methods necessitate rigorous procedures in reproducibility, delineation of volumes, dosimetry, daily treatment. They need also technological and human means. It is clear that localized prostate cancer is a good example for evaluation of these new radiotherapy modalities.     

调强适形放疗在乳腺癌保乳术后应用的系统评价

Objective

The aim of this study was to assess the long-term effect of breast conservation with breast intensity-modulated radiotherapy (IMRT) for early-stage breast cancers.

Methods

Pub Med, EMBASE, Cochrane Library, Chinese Biomedical Literature Database were searched to identify relevant original published trails, and the references of eligible studies were manually screened. Randomized controlled trails reported in any language, comparing breast IMRT with conventional radiotherapy (RT) in patients with early-stage breast cancer were eligible for inclusion. Two investigators independently assessed the quality of included trials and extracted data. The RevMan 5.0 software was used for statistical analysis.

Results

Four trials involving 1440 patients were included. The results showed that in the IMRT group, the occurrence of acute moist dermatitis, the edema of the mammary gland and the occurrence of hyperpigmentation were lower than those of RT group, the pooled risk ratio value and 95% confidence interval were 0.28 (0.17–0.48), 0.03 (0.00–0.21) and 0.06 (0.02–0.15) respectively. The use of IMRT did not correlate with pain and quality of life, but the presence of moist desquamation did significantly correlate with pain and reduced quality of life.

Conclusion

The currently available evidence showed that IMRT significantly reduces the occurrence of moist acute dermatitis anywhere in the breast and alleviates the suffering of patients and improves the quality of life of patients. Future large-scale, high-quality, double-blind trials are needed.     

Image-guided radiotherapy for rectal cancer: a systematic review

Radiotherapy for rectal cancer is becoming more conformal. Both the rectum and the mesorectum are mobile structures and the use of image-guided radiotherapy techniques may improve treatment delivery. Studies up to 2008 have previously been reviewed; rectal motion was mostly studied in bladder and prostate cancer cases. Large variations were seen in both the rectal volume and rectal wall displacement during the treatment course. We reviewed the literature on primary rectal cancer. A systematic review was conducted using Medline and Embase databases using the keywords 'rectal, radiotherapy, IGRT, image guided, organ motion, internal margin, target shape/volume'. Nine studies looked at both inter- and intrafractional motion of the gross tumour volume, rectum, mesorectum and the clinical target volume using a variety of imaging modalities. There was significant movement in the upper mesorectum. There was a strong relationship between rectal filling and mesorectal motion. Differences according to gender and body mass index have been reported. One study showed adequate dose to the rectum despite rectal motion and deformation. Current margin recipes may not apply to deformable structures. Suggested margins for the clinical target volume to planning target volume expansion are between 1 and 3.5cm. There may be a role for re-imaging and re-planning during a treatment course. From the available data, electronic portal imaging devices should continue to be used to match for bony anatomy. Additional information on internal motion can be obtained by cone beam computer tomography or tomotherapy and if available its use should be considered. Individualised anisotropic margins may be required. Further work is required to assess the optimal imaging modality, whether to match to bone or soft tissue, and to assess if internal motion affects treatment outcome.     

Intraoperative radiotherapy in pancreatic cancer: a systematic review.

BACKGROUND AND PURPOSE: Intraoperative radiotherapy (IORT) has been considered for treatment of pancreas cancer since local recurrence rates are very high. This study assesses the efficacy and safety of IORT in pancreatic cancer. MATERIALS AND METHODS: We conducted a systematic review of scientific literature from January 1995 to February 2007, including Medline, Embase, ISI Web of Science and HTA (Health Technology Assessment). By applying a series of inclusion criteria, two independent reviewers selected those studies in which a minimum of 30 patients received IORT and which furnished survival results based on a minimum 3-month follow-up. RESULTS: Fourteen papers were included, one was an IORT assessment report, 5 were cohort studies, and the remaining 8 were case series studies, 2 of which belonged to the same series. In general, these studies showed that IORT could slightly increase survival among patients with pancreatic cancer in localized stages. However, the results were not conclusively in favor of IORT in the case of pancreatic cancer in locally advanced and metastatic stages. There were no published studies that assessed quality of life. CONCLUSIONS: There is no clear evidence to indicate that IORT is more effective than other therapies in treating pancreatic cancer in locally advanced and metastatic stages.     

Conformal radiotherapy in the adjuvant treatment of gastric cancer: Review of 82 cases

BACKGROUND: The Intergroup 0116 study showed a survival benefit with adjuvant chemoradiotherapy (CRT) for resected gastric cancer. We report our experience using conformal radiotherapy (RT). METHODS AND MATERIALS: Eighty-two patients with resected gastric or gastroesophageal junction (GEJ) adenocarcinoma, Stage IB to IV (M0), were treated with 45 Gy in 25 fractions using a 5-field conformal technique. Chemotherapy was in accordance with the Intergroup 0116 study, or infusional 5-fluorouracil and cisplatin in a phase I/II trial. RESULTS: Mean age was 56.4 years. Median follow-up was 22.8 months. Grade 3 or greater acute toxicity (National Cancer Institute Common Terminology Criteria of Adverse Events, version 3.0) was noted in 57% of patients (upper gastrointestinal tract 34%, hematologic 33%). One patient died of neutropenic sepsis. Radiation Therapy Oncology Group Grade 3 late toxicity included esophageal strictures (3 patients) and small bowel obstruction (1 patient). Full course CRT was completed by 67% of patients. Of 26 patients who relapsed, 20 died. Site of first relapse was available on 23 patients: 8 locoregional and distant, 4 locoregional alone, 11 distant alone. Overall and relapse-free survival were 69% and 54% at 3 years. CONCLUSION: Adjuvant CRT for gastric cancer, even with conformal RT, is associated with significant toxicity. Survival was comparable to that reported in the Intergroup 0116 study.     

Cytological diagnosis of prostatic cancer]

The authors has made 836 cytological assays in 184 patients with adenoma and cancer of the prostate. Eighty patients were examined using the complex technic (the puncture material and secretion of the prostate, and urine for the presence of atypical cells). Cytographs characteristic of such prestatic lesions are described.     

Palliative thoracic radiotherapy for non-small-cell lung cancer: a systematic review

Non-small-cell lung cancer is one of the most common malignant tumors worldwide. The majority of patients are not treatable with curative intent because of the extent of disease or patient comorbidity. Radiotherapy to the primary intrathoracic tumor is used with the aim of palliating troublesome local symptoms in approximately 25% of patients. The dose/fractionation regimens used evolved empirically, and surveys have shown widespread variation. It has not yet been clearly established which regimens give the most benefit and least toxicity. This systematic review identified 12 randomized controlled trials comparing palliative external beam radiotherapy regimens. Narrative synthesis has been performed. Palliative radiotherapy is effective in controlling symptoms. There is no strong evidence that better palliation is obtained with higher radiation doses but good evidence that toxicity is greater. There is evidence of a modest survival benefit with higher dose schedules in patients with good performance status. The majority of patients should receive short courses (one or two fractions) of hypofractionated radiotherapy, Selected patients with good performance status should be considered for higher dose regimens if the chance of modest improvement in survival and palliation is considered worth the additional inconvenience and toxicity.     

适形放射治疗联合热疗治疗晚期胰腺癌的疗效及临床受益反应观察

为了评价适形放疗联合热疗治疗晚期胰腺癌的疗效及临床受益反应,对34例胰腺癌患者给予适形放疗,2Gy/次,5次/周,总剂量50-70 Gy;热疗2次/周,每次60-90 min,共计6次。结果82.4%患者胸背部疼痛明显缓解,临床受益反应有效率91.2%;放疗后2个月复查CT,肿瘤缩小〉25%者76.5%;1、2年生存率分别为38.2%和20.6%。初步研究结果提示,适形放射治疗联合热疗治疗晚期胰腺癌,疗效较好,并发症少,可显著提高患者生活质量,是不能手术患者较好的治疗方式。