Clinical dose-volume histogram analysis for pneumonitis after 3D treatment for non-small cell lung cancer (NSCLC)

PURPOSE

To identify a clinically relevant and available parameter upon which to identify non-small cell lung cancer (NSCLC) patients at risk for pneumonitis when treated with three-dimensional (3D) radiation therapy.

METHODS AND MATERIALS

Between January 1991 and October 1995, 99 patients were treated definitively for inoperable NSCLC. Patients were selected for good performance status (96%) and absence of weight loss (82%). All patients had full 3D treatment planning (including total lung dose-volume histograms [DVHs]) prior to treatment delivery. The total lung DVH parameters were compared with the incidence and grade of pneumonitis after treatment.

RESULTS

Univariate analysis revealed the percent of the total lung volume exceeding 20 Gy (V20), the effective volume (Veff) and the total lung volume mean dose, and location of the tumor primary (upper versus lower lobes) to be statistically significant relative to the development of > or = Grade 2 pneumonitis. Multivariate analysis revealed the V20 to be the single independent predictor of pneumonitis.

CONCLUSIONS

The V20 from the total lung DVH is a useful parameter easily obtained from most 3D treatment planning systems. The V20 may be useful in comparing competing treatment plans to evaluate the risk of pneumonitis for our individual patient treatment and may also be a useful parameter upon which to stratify patients or prospective dose escalation trials.

Dose-volume histograms

A plot of a cumulative dose-volume frequency distribution, commonly known as a dose-volume histogram (DVH), graphically summarizes the simulated radiation distribution within a volume of interest of a patient which would result from a proposed radiation treatment plan. DVHs show promise as tools for comparing rival treatment plans for a specific patient by clearly presenting the uniformity of dose in the target volume and any hot spots in adjacent normal organs or tissues. However, because of the loss of positional information in the volume(s) under consideration, it should not be the sole criterion for plan evaluation. DVHs can also be used as input data to estimate tumor control probability (TCP) and normal tissue complication probability (NTCP). The sensitivity of TCP and NTCP calculations to small changes in the DVH shape points to the need for an accurate method for computing DVHs. We present a discussion of the methodology for generating and plotting the DVHs, some caveats, limitations on their use and the general experience of four hospitals using DVHs.

Heart toxicity from breast cancer radiotherapy : Current findings, assessment, and prevention

Background

Late cardiac toxicities caused by (particularly left-sided) breast radiotherapy (RT) are now recognized as rare but relevant sequelae, which has prompted research on risk structure identification and definition of threshold doses to heart subvolumes. The aim of the present review was to critically discuss the clinical evidence on late cardiac reactions based on dose-dependent outcome reports for mean heart doses as well as doses to cardiac substructures.

Methods

A literature review was performed to examine clinical evidence on radiation-induced heart toxicities. Mean heart doses and doses to cardiac substructures were focused upon based on dose-dependent outcome reports. Furthermore, an overview of radiation techniques for heart protection is given and non-radiotherapeutic aspects of cardiotoxicity in the multimodal setting of breast cancer treatment are discussed.

Results

Based on available findings, the DEGRO breast cancer expert panel recommends the following constraints: mean heart dose <2.5 Gy; D_meanLV (mean dose left ventricle) < 3 Gy; V5_LV (volume of LV receiving ≥5 Gy) < 17%; V23_LV (volume of LV receiving ≥23 Gy) < 5%; D_meanLAD (mean dose left descending artery) < 10 Gy; V30_LAD (volume of LAD receiving ≥30 Gy) < 2%; V40_LAD (volume of LAD receiving ≥40 Gy) < 1%.

Conclusion

In addition to mean heart dose, breast cancer RT treatment planning should also include constraints for cardiac subvolumes such as LV and LAD. The given constraints serve as a clinicians’ aid for ensuring adequate heart protection. The individual decision between sufficient protection of cardiac structures versus optimal target volume coverage remains in the physician’s hand. The risk of breast cancer-specific mortality and a patient’s cardiac risk factors must be individually weighed up against the risk of radiation-induced cardiotoxicity.

Accuracy of a commercial optical 3D surface imaging system for realignment of patients for radiotherapy of the thorax

Accurate and reproducible patient setup is a prerequisite to fractionated radiotherapy. To evaluate the applicability and technical performance of a commercial 3D surface imaging system for repositioning of breast cancer patients, measurements were performed in a rigid anthropomorphic phantom as well as in healthy volunteers. The camera system records a respiration-gated surface model of the imaged object, which may be registered to a previously recorded reference model. A transformation is provided, which may be applied to the treatment couch to correct the setup of the patient. The system showed a high stability and detected pre-defined shifts of phantoms and healthy volunteers with an accuracy of 0.40 +/- 0.26 mm and 1.02 +/- 0.51 mm, respectively (spatial deviation between pre-defined shift and suggested correction). The accuracy of the suggested rotational correction around the vertical axis was always better than 0.3 degrees in phantom measurements and 0.8 degrees in volunteers, respectively. Comparison of the suggested setup correction with that detected by a second and independently operated marker-based optical system provided consistent results. The results demonstrate that the camera system provides highly accurate setup corrections in a phantom and healthy volunteers. The most efficient use of the system for improving the setup accuracy in breast cancer patients has to be investigated in routine patient treatments.

DEGRO practical guidelines: radiotherapy of breast cancer I: radiotherapy following breast conserving therapy for invasive breast cancer

BACKGROUND AND PURPOSE

The aim of the present paper is to update the practical guidelines for postoperative adjuvant radiotherapy of breast cancer published in 2007 by the breast cancer expert panel of the German Society for Radiooncology (Deutsche Gesellschaft für Radioonkologie, DEGRO). The present recommendations are based on a revision of the German interdisciplinary S-3 guidelines published in July 2012.

METHODS

A comprehensive survey of the literature concerning radiotherapy following breast conserving therapy (BCT) was performed using the search terms "breast cancer", "radiotherapy", and "breast conserving therapy". Data from lately published meta-analyses, recent randomized trials, and guidelines of international breast cancer societies, yielding new aspects compared to 2007, provided the basis for defining recommendations according to the criteria of evidence-based medicine. In addition to the more general statements of the DKG (Deutsche Krebsgesellschaft), this paper addresses indications, target definition, dosage, and technique of radiotherapy of the breast after conservative surgery for invasive breast cancer.

RESULTS

Among numerous reports on the effect of radiotherapy during BCT published since the last recommendations, the recent EBCTCG report builds the largest meta-analysis so far available. In a 15 year follow-up on 10,801 patients, whole breast irradiation (WBI) halves the average annual rate of disease recurrence (RR 0.52, 0.48-0.56) and reduces the annual breast cancer death rate by about one sixth (RR 0.82, 0.75-0.90), with a similar proportional, but different absolute benefit in prognostic subgroups (EBCTCG 2011). Furthermore, there is growing evidence that risk-adapted dose augmentation strategies to the tumor bed as well as the implementation of high precision RT techniques (e.g., intraoperative radiotherapy) contribute substantially to a further reduction of local relapse rates. A main focus of ongoing research lies in partial breast irradiation strategies as well as WBI hypofractionation schedules. The potential of both in replacing normofractionated WBI has not yet been finally clarified.

CONCLUSION

After breast conserving surgery, no subgroup even in low risk patients has yet been identified for whom radiotherapy can be safely omitted without compromising local control and, hence, cancer-specific survival. In most patients, this translates into an overall survival benefit.

Heart-sparing radiotherapy techniques in breast cancer patients: a recommendation of the breast cancer expert panel of the German society of radiation oncology (DEGRO)

PURPOSE

The aim of this review was to analyze the respective efficacy of various heart-sparing radiotherapy techniques.

MATERIAL AND METHODS

Heart-sparing can be performed in three different ways in breast cancer radiotherapy: by seeking to keep the heart out of treated volumes (i.e. by prone position or specific breathing techniques such as deep inspiration breath-hold [DIBH] and/or gating), by solely irradiating a small volume around the lumpectomy cavity (partial breast irradiation, PBI), or by using modern radiation techniques like intensity-modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT) or protons. This overview presents the available data on these three approaches.

RESULTS

Studies on prone position are heterogeneous and most trials only refer to patients with large breasts; therefore, no definitive conclusion can be drawn for clinical routine. Nonetheless, there seems to be a trend toward better sparing of the left anterior descending artery in supine position even for these selected patients. The data on the use of DIBH for heart-sparing in breast cancer patients is consistent and the benefit compared to free-breathing is supported by several studies. In comparison with whole breast irradiation (WBI), PBI has an advantage in reducing the heart dose. Of note, DIBH and PBI with multicatheter brachytherapy are similar with regard to the dose reduction to heart structures. WBI by IMRT/VMAT techniques without DIBH is not an effective strategy for heart-sparing in breast cancer patients with "standard" anatomy. A combination of DIBH and IMRT may be used for internal mammary radiotherapy.

CONCLUSION

Based on the available findings, the DEGRO breast cancer expert panel recommends the use of DIBH as the best heart-sparing technique. Nonetheless, depending on the treatment volume and localization, other techniques may be employed or combined with DIBH when appropriate.

Intraoperative electron-beam therapy for primary and recurrent retroperitoneal soft-tissue sarcoma

PURPOSE

This study assesses the long-term outcome of patients with retroperitoneal soft-tissue sarcomas treated by maximal resection in combination with intraoperative electron-beam therapy (IOERT) and postoperative external-beam radiotherapy.

METHODS AND MATERIALS

From 1991 to 2004, 67 patients were treated with curative intent for primary (n = 26) or recurrent (n = 41) retroperitoneal soft-tissue sarcoma. All patients underwent maximal resection in combination with IOERT (mean dose, 15 Gy), 45 patients underwent additional postoperative EBRT, and 20 patients were previously irradiated.

RESULTS

The 5-year actuarial overall survival (OS), disease-free survival, local control (LC), and freedom from metastatic disease of all patients was 64%, 28%, 40%, and 50%, respectively. The 5-year LC inside the IOERT field was 72%. For patients who completed IOERT and EBRT after R0-resection 5-year and 10-year OS was 80%, and 5-year and 10-year LC was 100%. Only 1 of the 21 patients after R0-resection and only 8 of 34 patients after R1-resection compared with 9 of 12 patients after R2-resection experienced inside IOERT-field relapse. Grade II or higher late complications were seen in 21% of the patients, but only 2 patients required surgical intervention because of late complications.

CONCLUSION

In selected patients, IOERT results in excellent local control and survival, with acceptable morbidity.

DEGRO practical guidelines for radiotherapy of breast cancer VI: therapy of locoregional breast cancer recurrences

Objective

To update the practical guidelines for radiotherapy of patients with locoregional breast cancer recurrences based on the current German interdisciplinary S3 guidelines 2012.

Methods

A comprehensive survey of the literature using the search phrases “locoregional breast cancer recurrence”, “chest wall recurrence”, “local recurrence”, “regional recurrence”, and “breast cancer” was performed, using the limits “clinical trials”, “randomized trials”, “meta-analysis”, “systematic review”, and “guidelines”.

Conclusions

Patients with isolated in-breast or regional breast cancer recurrences should be treated with curative intent. Mastectomy is the standard of care for patients with ipsilateral breast tumor recurrence. In a subset of patients, a second breast conservation followed by partial breast irradiation (PBI) is an appropriate alternative to mastectomy. If a second breast conservation is performed, additional irradiation should be mandatory. The largest reirradiation experience base exists for multicatheter brachytherapy; however, prospective clinical trials are needed to clearly define selection criteria, long-term local control, and toxicity.

Following primary mastectomy, patients with resectable locoregional breast cancer recurrences should receive multimodality therapy including systemic therapy, surgery, and radiation +/− hyperthermia. This approach results in high local control rates and long-term survival is achieved in a subset of patients. In radiation-naive patients with unresectable locoregional recurrences, radiation therapy is mandatory. In previously irradiated patients with a high risk of a second local recurrence after surgical resection or in patients with unresectable recurrences, reirradiation should be strongly considered. Indication and dose concepts depend on the time interval to first radiotherapy, presence of late radiation effects, and concurrent or sequential systemic treatment. Combination with hyperthermia can further improve tumor control.

In patients with isolated axillary or supraclavicular recurrence, durable disease control is best achieved with multimodality therapy including surgery and radiotherapy. Radiation therapy significantly improves local control and should be applied whenever feasible.

Preliminary evaluation of low-grade toxicity with conformal radiation therapy for prostate cancer on RTOG 9406 dose levels I and II

PURPOSE

To evaluate the rates of low-grade late effects in patients treated for prostate cancer on Radiation Therapy Oncology Group (RTOG) 9406.

MATERIALS AND METHODS

Between August 1994 and September 1999, 424 patients were entered on this dose escalation trial of three-dimensional conformal radiation therapy (3D-CRT) for localized adenocarcinoma of the prostate at doses of 68.4 Gy (level I) and 73.8 Gy (level II). We have previously reported Grade 3 or greater late toxicity of patients treated on the first two dose levels of this trial. This analysis examines the distribution of all late toxicities in these patients. All radiation prescriptions were a minimum dose to a planning target volume (PTV). Patients were stratified according to clinical stage and risk of seminal vesicle invasion (SVI) based upon Gleason score and presenting prostate-specific antigen. Group 1 includes patients with T1,2 disease with SVI risk < 15%, and Group 2 includes patients with T1,2 disease with SVI risk > 15%. Group 3 patients had T3 disease. Average months at risk after completion of therapy ranged from 21.4 to 40.1 months for patients treated at dose level I and 10.0 to 34.2 months for patients at dose level II. The frequency of all grades of late effects was compared with a similar group of patients treated in RTOG studies 7506 and 7706 with adjustments made for the interval from completion of therapy. The RTOG toxicity scoring scales for late effects were used for grading.

RESULTS

The rate of Grade 3 or greater late toxicity continues to be low compared with RTOG historical controls. No Grade 4 or 5 late sequelae were reported in any of the 393 evaluable patients during the period of observation. The frequency of patients free of any complications was lower in RTOG 9406 than in historical controls. In the 73 Group 1 patients treated on dose level 1, there were 24 patients without sequelae compared with an expected rate of 39.7 (p = 0.013), and in 80 Group 3 patients at dose level II there were 24 patients without sequelae when 56.2 were expected (p < 0.0001). Other groups treated at these dose levels demonstrated a nonsignificant reduction in the rate of patients free of any side effects. These data suggest that the reduction in high-grade morbidity may be related to a shift of complications to lower grades.

CONCLUSIONS

Morbidity of 3D-CRT in the treatment of prostate cancer is low. It is important to continue to closely examine late effects in patients treated in RTOG 9406. The primary objective of dose escalation without an increase rate of >/= Grade 3 sequelae has been achieved. However, the reduction in Grade 3 complications may have resulted in a higher incidence of Grade 1 or 2 late effects. Because Grade 2 late effects may have a significant impact on a patient's quality of life, it is important to reduce these complications as much as possible. Clinical trials should use quality-of-life measures to determine that trade-offs between severity and rates of toxicity are acceptable to patients.

Open low-field magnetic resonance imaging in radiation therapy treatment planning

PURPOSE

To evaluate the possibilities of an open low-field magnetic resonance imaging (MRI) scanner in external beam radiotherapy treatment (RT) planning.

METHODS AND MATERIALS

A custom-made flat tabletop was constructed for the open MR, which was compatible with standard therapy positioning devices. To assess and correct image distortion in low-field MRI, a custom-made phantom was constructed and a software algorithm was developed. A total of 243 patients (43 patients with non-small-cell lung cancer, 155 patients with prostate cancer, and 45 patients with brain tumors) received low-field MR imaging in addition to computed tomographic (CT) planning imaging between January 1998 and September 2001 before the start of the irradiation.

RESULTS

Open low-field MRI provided adequate images for RT planning in nearly 95% of the examined patients. The mean and the maximal distortions 15 cm around the isocenter were reduced from 2.5 mm to 0.9 mm and from 6.1 mm to 2.1 mm respectively. The MRI-assisted planning led to better discrimination of tumor extent in two-thirds of the patients and to an optimization in lung cancer RT planning in one-third of the patients. In prostate cancer planning, low-field MRI resulted in significant reduction (40%) of organ volume and clinical target volume (CTV) compared with CT and to a reduction of the mean percentage of rectal dose of 15%. In brain tumors, low-field MR image quality was superior compared with CT in 39/45 patients for planning purposes.

CONCLUSIONS

The data presented here show that low-field MRI is feasible in RT treatment planning when image correction regarding system-induced distortions is performed and by selecting MR imaging protocol parameters with the emphasis on adequate images for RT planning.

DEGRO practical guideline for partial-breast irradiation

PURPOSE

This consensus statement from the Breast Cancer Working Group of the German Society for Radiation Oncology (DEGRO) aims to define practical guidelines for accelerated partial-breast irradiation (APBI).

METHODS

Recent recommendations for relevant aspects of APBI were summarized and a panel of experts reviewed all the relevant literature. Panel members of the DEGRO experts participated in a series of conferences, supplemented their clinical experience, performed a literature review, and formulated recommendations for implementing APBI in clinical routine, focusing on patient selection, target definition, and treatment technique.

RESULTS

Appropriate patient selection, target definition for different APBI techniques, and basic rules for appropriate APBI techniques for clinical routine outside of clinical trials are described. Detailed recommendations for APBI in daily practice, including dose constraints, are given.

CONCLUSION

Guidelines are mandatory to assure optimal results of APBI using different techniques.

Image fusion of CT and MRI data enables improved target volume definition in 3D-brachytherapy treatment planning

PURPOSE

To integrate MRI into CT-based 3D-brachytherapy treatment planning using a software system for image registration and fusion.

METHODS AND MATERIALS

Sixteen patients with recurrent head-and-neck cancer, vulvar cancer, liposarcoma, and cervical cancer were treated with interstitial (n=12) and endocavitary (n=4) brachytherapy. CT and MRI scans were performed after implantation and prior to treatment planning. Image registration to integrate the CT and MR information into a single geometric framework was performed using a software algorithm based on mutual information. Conventional 3D-brachytherapy planning based on CT-information alone was compared to brachytherapy planning based on fused CT and MRI data. The accuracy of the image fusion was measured using predefined corresponding landmarks in the CT and MRI data.

RESULTS

The presented automated algorithm proved to be robust and reliable (mean registration error 1.8 mm, range 0.8-4.1 mm, SD 0.9 mm). Tumor visualization was difficult using CT alone in all cases. Brachytherapy treatment planning based on fused CT and MRI data enabled better definition of target volume and risk structures as compared to treatment planning based on CT alone.

CONCLUSIONS

Image registration and fusion is feasible for afterloading brachytherapy treatment planning. Treatment planning based on fused CT and MRI data resulted in improved target volume and risk structure definition.

Helical tomotherapy as a new treatment technique for whole abdominal irradiation

PURPOSE

To describe a new intensity-modulated radiotherapy (IMRT) technique using helical tomotherapy for whole abdominal irradiation (WAI) in patients with advanced ovarian cancer.

MATERIAL AND METHODS

A patient with radically operated ovarian cancer FIGO stage IIIc was treated in a prospective clinical trial with WAI to a total dose of 30 Gy in 1.5-Gy fractions as an additional therapy after adjuvant platinum-based chemotherapy. The planning target volume (PTV) included the entire peritoneal cavity. PTV was adapted according to breathing motion as detected in a four-dimensional respiratory-triggered computed tomography (4D-CT). Inverse treatment planning was done with the Hi-Art tomotherapy planning station. Organs at risk (OARs) were kidneys, liver, bone marrow, spinal cord, thoracic and lumbosacral vertebral bodies, and pelvic bones. Daily control of positioning accuracy was performed with megavoltage computed tomography (MV-CT).

RESULTS

Helical tomotherapy enabled a very homogeneous dose distribution with excellent sparing of OARs and coverage of the PTV (V90 of 93.1%, V95 of 86.9%, V105 of 1.9%, and V110 of 0.01%). Mean liver dose was 21.57 Gy and mean kidney doses were 9.75 Gy and 9.14 Gy, respectively. Treatment could be performed in 18.1 min daily and no severe side effects occurred.

CONCLUSION

Helical tomotherapy is feasible and fast for WAI. Tomotherapy enabled excellent coverage of the PTV and effective sparing of liver, kidneys and bone marrow.

Intercomparison experiments of systems for the measurement of xenon radionuclides in the atmosphere

Radioactive xenon monitoring is one of the main technologies used for the detection of underground nuclear explosions. Precise and reliable measurements of (131m)Xe, (133g)Xe, (133m)Xe, and (135g)Xe are required as part of the International Monitoring System for compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). For the first time, simultaneous testing of four highly sensitive and automated fieldable radioxenon measurement systems has been performed and compared to established laboratory techniques. In addition to an intercomparison of radioxenon monitoring equipment of different design, this paper also presents a set of more than 2000 measurements of activity concentrations of radioactive xenon made in the city of Freiburg, Germany in 2000. The intercomparison experiment showed, that the results from the newly developed systems agree with each other and the equipment fulfills the fundamental requirements for their use in the verification regime of the CTBT. For 24-h measurements, concentrations as low as 0.1 mBqm(-3) were measured for atmospheric samples ranging in size from 10 to 80 m(3). The (133)Xe activity concentrations detected in the ambient air ranged from below 1 mBqm(-3) to above 100 mBqm(-3).

Patterns of failure and local control after intraoperative electron boost radiotherapy to the presacral space in combination with total mesorectal excision in patients with locally advanced rectal cancer

PURPOSE

To evaluate local control and patterns of failure in patients treated with intraoperative electron beam radiotherapy (IOERT) after total mesorectal excision (TME), to appraise the effectiveness of intraoperative target definition.

METHODS AND MATERIALS

We analyzed the outcome of 243 patients with rectal cancer treated with IOERT (median dose, 10 Gy) after TME. Eighty-eight patients received neoadjuvant and 122 patients adjuvant external beam radiotherapy (EBRT) (median dose, 41.4 Gy), and in 88% simultaneous chemotherapy was applied. Median follow-up was 59 months.

RESULTS

Local failure was observed in 17 patients (7%), resulting in a 5-year local control rate of 92%. Only complete resection and absence of nodal involvement correlated positively with local control. Considering IOERT fields, seven infield recurrences were seen in the presacral space, resulting in a 5-year local control rate of 97%. The remaining local relapses were located as follows: retrovesical/retroprostatic (5), anastomotic site (2), promontorium (1), ileocecal (1), and perineal (1).

CONCLUSION

Intraoperative electron beam radiotherapy as part of a multimodal treatment approach including TME is a highly effective regimen to prevent local failure. The presacral space remains the site of highest risk for local failure, but IOERT can decrease the percentage of relapses in this area.

Electromagnetically Navigated Brachytherapy as a New Treatment Option for Peripheral Pulmonary Tumors

PURPOSE

This technical note describes the principles of navigated brachytherapy for treatment of peripheral non-small cell lung cancer (NSCLC).

MATERIAL AND METHODS

In a prospective feasibility trial a first patient with medically inoperable NSCLC in the right upper lobe was treated with external-beam radiotherapy (50 Gy) and navigated endoluminal brachytherapy (15 Gy). Navigated bronchoscopy was performed with an electromagnetic navigation system for localization of a microsensor mounted on the tip of a dedicated catheter placed within the working channel of a bronchoscope. The probe can be actively guided by a steering mechanism to targeted lesions in the periphery of the lung. After successful localization of the NSCLC, endobronchial ultrasound (EBUS) was performed to confirm the exact position in the center of the lesion. A 6-F brachytherapy catheter was placed within the tumor. Primary 3-D-planned brachytherapy was performed on chest CTs acquired with the inserted catheter. High-dose-rate brachytherapy (370 GBq iridium-192) was applied as a boost three times a week (single dose 5 Gy) and provided highly conformal irradiations of the NSCLC including the draining bronchovascular bundle.

RESULTS

The brachytherapy catheter was tolerated well during treatment (5 days) and alimentation was possible without any problems. Repeated CTs showed stable positioning of the catheter. During follow-up (12 months), endoluminal ultrasound and CT demonstrated a partial remission while histology showed a complete remission of the tumor.

CONCLUSION

Navigated brachytherapy for peripheral pulmonary tumors not amenable to conventional bronchoscopy is feasible.

Results of chest wall reirradiation using pulsed-dose-rate (PDR) brachytherapy molds for breast cancer local recurrences

PURPOSE

We report in a retrospective study on the effect and toxicity of chest wall reirradiation using pulsed-dose-rate (PDR) afterloading molds.

METHODS AND MATERIALS

Between 1993 and 1999, a total of 58 patients were treated. All patients presented with locally recurrent breast cancer (31 patients had concomitant distant metastases) after mastectomy and a previously completed course of radiation therapy (median, 54 Gy; range, 36-70). Indication for reirradiation was a progressive macroscopic skin recurrence in 30 cases and an incomplete surgical resection in 28 patients. Standard treatment consisted of a split course with two fractions of 20 Gy (interval, 31 days). The reference dose was prescribed to the skin surface at 5 mm distance from the source. PDR brachytherapy (37 GBq, (192)Ir) was carried out after geometric distance optimization with 0.5-1 Gy/pulse/h. The irradiated median area was 423 cm(2) (range, 100-919). The median follow-up was 18 months (range, 7-84).

RESULTS

The actuarial 1-, 2- and 3-year local recurrence-free survival rates in patients treated for macroscopic disease (microscopic disease in parenthesis) were 89% (96%), 81% (85%), and 75% (71%). Local control was obtained in 24/30 (22/28) patients. Twenty-nine of the 34 patients (85%) who deceased during follow-up were locally controlled. 9/58 patients experienced Grade III acute toxicity, 35/58 patients Grade III (29/58 telangiectasia, 6/58 contracture), and 4/58 Grade IV late toxicity (RTOG/EORTC).

CONCLUSION

Reirradiation of the chest wall using PDR brachytherapy molds is effective and provides a high local control rate with acceptable toxicity.

Intensity-modulated radiotherapy of the female breast

Current methods for intensity-modulated radiotherapy (IMRT) in breast cancer use forward planning based on equivalent radiological path length to design intensity modulated tangential beams. Compared to conventional tangential techniques, dose reduction of organs at risk is limited using these techniques. We developed a method for intensity modulation of multiple beams for adjuvant radiotherapy of breast cancer by application of a virtual bolus defined on CT for inverse optimization. This method enables multibeam IMRT, which provides improved sparing of lung and heart tissue. In this paper, we present the general aspects of this approach and an evaluation of the optimum beam configuration for IMRT based on inverse treatment planning. We compared this method to conventional techniques. Different clinical examples illustrate the possible indications and feasibility of this new approach. This method is superior to conventional techniques because of the reduction of high-dose area of a substantial cardiac volume in those cases where the parasternal lymph nodes are part of the target volume.

Accelerated partial breast irradiation

BACKGROUND

Breast-conserving surgery followed by whole-breast radiotherapy (WBRT) has become the standard treatment for the majority of patients with early breast cancer. Whereas the indications for systemic adjuvant treatment have continuously expanded, there is a tendency to restrict postoperative radiotherapy to accelerated partial breast irradiation (APBI) instead of WBRT.

METHODS

The different techniques of APBI are described and their respective advantages or potential drawbacks outlined. Moreover, the results described in the literature are briefly reviewed as a basis for the consensus statements and recommendations of the German Society of Radiation Oncology, the German Society of Senology, and the Working Group for Gynecological Oncology of the German Cancer Society.

RESULTS

The methods mainly used for APBI are: interstitial radiotherapy with multicatheter technique, intraoperative radiotherapy (IORT) using either electrons produced by linear accelerators or 50 kV x-rays (Intrabeam), the balloon-catheter technique (MammoSite), or 3D conformal external beam radiotherapy. These techniques have marked differences in dose distribution and homogeneity. The published range of local recurrence rates varies between 0% to 37%, the median follow-up from 8 to 72 months.

CONCLUSIONS

To date, follow-up times mostly do not yet permit a definite judgment concerning the long-term effectiveness and side effects of APBI. The relevant societies in Germany support randomized clinical studies comparing APBI with WBRT in a well-defined subset of low-risk patients. However, the authors expressly discourage the routine use of APBI outside clinical trials. Until definite results show that APBI neither impairs therapeutic outcome nor cosmetic results, WBRT remains the gold standard in the treatment of early breast cancer.

Three-dimensional treatment planning and conformal radiation therapy: preliminary evaluation

Preliminary clinical results are presented for 209 patients with cancer who had treatment planned on our three-dimensional radiation treatment planning (3-D RTP) system and were treated with external beam conformal radiation therapy. Average times (min) for CT volumetric simulation were: 74 without or 84 with contrast material; 36 for contouring of tumor/target volume and 44 for normal anatomy; 78 for treatment planning; 53 for plan evaluation/optimization; and 58 for verification simulation. Average time of daily treatment sessions with 3-D conformal therapy or standard techniques was comparable for brain, head and neck, thoracic, and hepatobiliary tumors (11.8-14 min and 11.5-12.1, respectively). For prostate cancer patients treated with 3-D conformal technique and Cerrobend blocks, mean treatment time was 19 min; with multileaf collimation it was 14 min and with bilateral arc rotation, 9.8 min. Acute toxicity was comparable to or lower than with standard techniques. Sophisticated 3-D RTP and conformal irradiation can be performed in a significant number of patients at a reasonable cost. Further efforts, including dose-escalation studies, are necessary to develop more versatile and efficient 3-D RTP systems and to enhance the cost benefit of this technology in treatment of patients with cancer.

Intraoperative radiotherapy as accelerated partial breast irradiation for early breast cancer : beware of one-stop shops?

Intraoperative radiotherapy (IORT) was originally introduced in breast cancer treatment as an "anticipated boost" during the procedure of breast conserving surgery (BCS). In addition to whole breast irradiation (WBI), it has yielded excellent long-term results [31, 38]. Under the assumption that the majority of in-breast tumor recurrences (IBTR) occur in the originally affected site, accelerated partial breast irradiation (APBI) as the sole treatment modality was initiated in several studies and with different techniques, one of which was IORT first with electrons, later also with conventional x-rays [29]. The question whether and for whom the gold standard of WBI may be replaced by APBI - especially IORT - alone has recently been one of the most controversial issues of adjuvant therapy for breast cancer. Two recently published studies by Veronesi et al. [36] and Vaidya et al. [35] presenting shortterm results of single shot IORT with electrons (ELIOT) and with an orthovoltage system (TARGIT), respectively, have further invigorated this discussion as illustrated by several letters to the editor commenting on the TARGIT study. While Vaidya et al. [35] indicate their results of IORT alone as "an alternative to WBI for selected patients" and one editorial even proclaims it as standard [6], all the authors of the respective letters [10, 16, 27, 33] strongly disagree with this conclusion. The present editorial comments on the two publications and, furthermore, provides respective statements of the breast cancer expert panel of the German Society of Radiation Oncology (DEGRO).

DEGRO practical guidelines for radiotherapy of breast cancer IV: radiotherapy following mastectomy for invasive breast cancer

BACKGROUND AND PURPOSE

Since the last recommendations from the Breast Cancer Expert Panel of the German Society for Radiation Oncology (DEGRO) in 2008, evidence for the effectiveness of postmastectomy radiotherapy (PMRT) has grown. This growth is based on updates of the national S3 and international guidelines, as well as on new data and meta-analyses. New aspects were considered when updating the DEGRO recommendations.

METHODS

The authors performed a comprehensive survey of the literature. Data from recently published (meta-)analyses, randomized clinical trials and international cancer societies' guidelines yielding new aspects compared to 2008 were reviewed and discussed. New aspects were included in the current guidelines. Specific issues relating to particular PMRT constellations, such as the presence of risk factors (lymphovascular invasion, blood vessel invasion, positive lymph node ratio >20 %, resection margins <3 mm, G3 grading, young age/premenopausal status, extracapsular invasion, negative hormone receptor status, invasive lobular cancer, size >2 cm or a combination of ≥ 2 risk factors) and 1-3 positive lymph nodes are emphasized.

RESULTS

The evidence for improved overall survival and local control following PMRT for T4 tumors, positive resection margins, >3 positive lymph nodes and in T3 N0 patients with risk factors such as lymphovascular invasion, G3 grading, close margins, and young age has increased. Recently identified risk factors such as invasive lobular subtype and negative hormone receptor status were included. For patients with 1-3 positive lymph nodes, the recommendation for PMRT has reached the 1a level of evidence.

CONCLUSION

PMRT is mandatory in patients with T4 tumors and/or positive lymph nodes and/or positive resection margins. PMRT should be strongly considered in patients with T3 N0 tumors and risk factors, particularly when two or more risk factors are present.

Design of a fully integrated three-dimensional computed tomography simulator and preliminary clinical evaluation

PURPOSE

We describe the conceptual structure and process of a fully integrated three-dimensional (3-D) computed tomography (CT) simulator and present a preliminary clinical and financial evaluation of our current system.

METHODS AND MATERIALS

This is a preliminary report on 117 patients treated with external beam radiation therapy alone on whom a 3-D simulation and treatment plan and delivery were carried out from July 1, 1992, through June 30, 1993. The elements of a fully integrated 3-D CT simulator were identified: (a) volumetric definition of tumor volume and patient anatomy obtained with a CT scanner, (b) virtual simulation for beam setup and digitally reconstructed radiographs, (c) 3-D treatment planning for volumetric dose computation and plan evaluation, (d) patient-marking device to outline portal on patient's skin, and (e) verification (physical) simulation to verify portal placement on the patient. Actual time-motion (time and effort) recording was made by each professional involved in the various steps of the 3-D simulation and treatment planning on computer-compatible forms. Data were correlated with the anatomic site of the primary tumor being planned. Cost accounting of revenues and operation of the CT simulator and the 3-D planning was carried out, and projected costs per examination, depending on case load, were generated.

RESULTS

Average time for CT volumetric simulation was 74 min without or 84 min with contrast material. Average times were 36 min for contouring of tumor/target volume and 44 min for normal anatomy, 78 min for treatment planning, 53 min for plan evaluation/optimization, and 58 min for verification simulation. There were significant variations in time and effort according to the specific anatomic location of the tumor. Portal marking of patient on the CT simulator was not consistently satisfactory, and this procedure was usually carried out on the physical simulator. Based on actual budgetary information, the cost of a volumetric CT simulation (separate from the 3-D treatment planning) showed that 1500 examinations per year (six per day in 250 working days) must be performed to make the operation of the device cost effective. The same financial projections for the entire 3-D planning process and verification yielded five plans per day. Some features were identified that will improve the use of the 3-D simulator, and solutions are offered to incorporate them in existing devices.

CONCLUSIONS

Commercially available CT simulators lack some elements that we believe are critical in a fully integrated 3-D CT simulator. Sophisticated 3-D simulation and treatment planning can be carried out in a significant number of patients at a reasonable cost. Time and effort and therefore cost vary according to the anatomic site of the tumor being planned and the number of procedures performed. Further efforts are necessary, with collaboration of radiation oncologists, physicists, and manufacturers, to develop more versatile and efficient 3-D CT simulators, and additional clinical experience is required to make this technology cost effective in standard radiation therapy of patients with cancer.

Combination of early bisphosphonate administration and irradiation leads to improved remineralization and restabilization of osteolytic bone metastases in an animal tumor model

BACKGROUND

The goal of the current study was to analyze the combined effect of bisphosphonates (BPs) and irradiation on remineralization and restabilization of osteolytic bone metastases in an animal tumor model.

METHODS

Bone metastases were induced in male Wistar rats via intraosseous injection of the Walker carcinosarcoma 256B cell line into both proximal tibia metaphyses on Day 1 of the study. Three treatment groups were analyzed. All animals received a single radiation dose of 17 grays (in the form of 6-megaelectron-volt electrons) on Day 7 and were sacrificed on Day 49. Group 1 (the control group) was treated with irradiation only. Groups 2 and 3 received additional BPs (clodronate; daily intraperitoneal injection dose, 20 mg/kg per day). In Group 2, BPs were given before irradiation, on Days 3-6; this schedule later was referred to as early BP treatment. In Group 3, BPs were administered simultaneously with irradiation, on Days 7-10; this schedule later was referred to as simultaneous BP treatment. The endpoints of the study were bone density and microstructural parameters of bone on Day 49. Bone density was measured using X-ray absorption. Microstructural parameters of bone were assessed using histomorphometry. A total of thirty tibiae were analyzed in each group.

RESULTS

After irradiation, bone density was significantly higher among animals in the early BP treatment group compared with those in the control group and those in the simultaneous BP treatment group (P = 0.001). Histomorphometric analysis of bone showed significantly better-preserved (P < 0.001) microstructural parameters (bone area, trabecular number, and trabecular separation) in the early BP treatment group compared with the control and simultaneous BP treatment groups.

CONCLUSIONS

Early BP administration in combination with irradiation led to improved remineralization and restabilization of osteolytic bone metastases in an animal tumor model.

Projector-based augmented reality for intuitive intraoperative guidance in image-guided 3D interstitial brachytherapy

PURPOSE

The aim of this study is to implement augmented reality in real-time image-guided interstitial brachytherapy to allow an intuitive real-time intraoperative orientation.

METHODS AND MATERIALS

The developed system consists of a common video projector, two high-resolution charge coupled device cameras, and an off-the-shelf notebook. The projector was used as a scanning device by projecting coded-light patterns to register the patient and superimpose the operating field with planning data and additional information in arbitrary colors. Subsequent movements of the nonfixed patient were detected by means of stereoscopically tracking passive markers attached to the patient.

RESULTS

In a first clinical study, we evaluated the whole process chain from image acquisition to data projection and determined overall accuracy with 10 patients undergoing implantation. The described method enabled the surgeon to visualize planning data on top of any preoperatively segmented and triangulated surface (skin) with direct line of sight during the operation. Furthermore, the tracking system allowed dynamic adjustment of the data to the patient's current position and therefore eliminated the need for rigid fixation. Because of soft-part displacement, we obtained an average deviation of 1.1 mm by moving the patient, whereas changing the projector's position resulted in an average deviation of 0.9 mm. Mean deviation of all needles of an implant was 1.4 mm (range, 0.3-2.7 mm).

CONCLUSIONS

The developed low-cost augmented-reality system proved to be accurate and feasible in interstitial brachytherapy. The system meets clinical demands and enables intuitive real-time intraoperative orientation and monitoring of needle implantation.