Anatomical, clinical and radiological delineation of target volumes in breast cancer radiotherapy planning: individual variability, questions and answers

Regional Lymph Node Delineation variability and its Dosimetric Impact in Breast Cancer Radiotherapy

AIMS

To quantify the interobserver variability of regional lymph node delineation for breast cancer radiotherapy (RT) and establish whether a relationship exists between contouring variations and dosimetry using the FAST-Forward (FF) pre-trial RT quality assurance (QA) benchmark cases.

MATERIALS AND METHODS

As part of the pre-trial RT QA, local site principal investigators (PIs) were asked to complete a single outlining QA benchmark case involving the delineation of axillary lymph node clinical target volumes (LNCTVs) levels 1-4. These contours were evaluated for concordance against an expert defined consensus gold standard (GS) volume using various conformity indices (CIs): discordance index (DI), geographical miss index (GMI), Jaccard index (JCI), mean distance to conformity (MDC) for both over- and under- contouring. Descriptive statistics including interquartile range (IQR) was used to evaluate interobserver variation. Wilcoxon signed-rank tests were used to establish if there were any statistically significant differences in the dosimetric parameters between plans conforming to GS volume and the volumes from the individual PI.

RESULTS

Pre-trial outlining QA benchmark cases from 29/33 PIs were assessed. The median submitted LNCTV volume was 131.4 cc (IQR: 112.4 - 145.3) compared with the GS volume of 105.46 cc. For conformity indices, the median DI was 0.37 (IQR: 0.31 - 0.40), the median GMI was 0.21 (IQR: 0.13 - 0.28), the median JCI was 0.53 (IQR: 0.49 - 0.56), MDCunder was -0.43 (IQR: -0.64 - -0.32) and MDCover was 0.46 (IQR: 0.43 - 0.53). A dosimetric analysis showed all plans met the mandatory planning dose constraints but not the optimal objectives for target volumes as required in the trial protocol. Statistically significant differences were found in 7/13 organs at risk dosimetric parameters between plans conformed to individual PI volumes and the GS volume.

CONCLUSION

Analysis of the FF pre-trial QA outlining benchmark case highlights the interobserver variation that exists in axillary nodal CTV (levels 1-4) delineation. Conformity indices demonstrated moderate agreement with a median Jaccard conformity index of 0.53, with both under- and over-contouring observed. All QA submissions achieved the mandatory planning dose constraints but not all optimal dose objectives of the FF trial despite the interobserver variation in target volume contouring.

[The place of radiotherapy]

Radiation therapy (RT) is a key component of the management of elderly breast cancer patients. However, level I evidence in elderly patients is limited. Patient selection should include comorbidities and geriatric assessment. Advances in radiation planning and delivery are improving target coverage, reducing toxicity, and expanding treatment eligibility. Some alternative techniques, such as treatment in the lateral or prone position, may reduce the risk of toxicity. Shorter cycles of hypofractionated whole breast RT are safe and effective. In some cases, partial breast irradiation may be an option.

Geometric contour variation in clinical target volume of axillary lymph nodes in breast cancer radiotherapy: an AIRO multi-institutional study

OBJECTIVES

To determine interobserver variability in axillary nodal contouring in breast cancer (BC) radiotherapy (RT) by comparing the clinical target volume of participating single centres (SC-CTV) with a gold-standard CTV (GS-CTV).

METHODS

The GS-CTV of three patients (P1, P2, P3) with increasing complexity was created in DICOM format from the median contour of axillary CTVs drawn by BC experts, validated using the simultaneous truth and performance-level estimation and peer-reviewed. GS-CTVs were compared with the correspondent SC-CTVs drawn by radiation oncologists, using validated metrics and a total score (TS) integrating all of them.

RESULTS

Eighteen RT centres participated in the study. Comparative analyses revealed that, on average, the SC-CTVs were smaller than GS-CTV for P1 and P2 (by -29.25% and -27.83%, respectively) and larger for P3 (by +12.53%). The mean Jaccard index was greater for P1 and P2 compared to P3, but the overlap extent value was around 0.50 or less. Regarding nodal levels, L4 showed the highest concordance with the GS. In the intra-patient comparison, L2 and L3 achieved lower TS than L4. Nodal levels showed discrepancy with GS, which was not statistically significant for P1, and negligible for P2, while P3 had the worst agreement. DICE similarity coefficient did not exceed the minimum threshold for agreement of 0.70 in all the measurements.

CONCLUSIONS

Substantial differences were observed between SC- and GS-CTV, especially for P3 with altered arm setup. L2 and L3 were the most critical levels. The study highlighted these key points to address.

ADVANCES IN KNOWLEDGE

The present study compares, by means of validated geometric indexes, manual segmentations of axillary lymph nodes in breast cancer from different observers and different institutions made on radiotherapy planning CT images. Assessing such variability is of paramount importance, as geometric uncertainties might lead to incorrect dosimetry and compromise oncological outcome.

Comparison of Photon-electron and Photon Radiotherapy for Supraclavicular Lymph Nodes of Mastectomy Patients with Left-sided Breast Cancer

The aim of radiotherapy is to deliver the highest possible radiation dose to the tumor and the lowest radiation to normal tissues surrounding the tumor. In the present study, lymph nodes of the supraclavicular region were treated using two therapeutic techniques, namely photon technique (PT) and combinatory photon-electron technique (CPET). We recruited 50 patients with local lymph node metastasis. The photon energies were 6-15 MV. Furthermore, the electron beam energy was 18 MeV in CPET. The study findings revealed that the mean delivered dose to target volume was 41.12 ± 2.98Gy for PT and 44.56 ± 1.90Gy for CPET. The percentage of the target volume irradiated to 90% of the prescribed dose (V90) was calculated as 74.61% ± 9.30% and 82.06% ± 9.70% for PT and CPET, respectively. The mean dose delivered to the heart and lungs was not significantly different between the two groups. Furthermore, the maximum doses delivered to the spinal cord were 12.55Gy in PT and 8.89Gy in CPET. The mean doses delivered to the thyroid gland were 39.26 and 34.89Gy in PT and CPET. According to the study results, the maximum doses delivered to the spinal cord, head of the humerus bone, and thyroid were reduced significantly as measured the CPET technique. In contrast, no significant difference was observed regarding the dose delivered to the heart and lung. The dose delivered to the supraclavicular region determined by the CPET was significantly augmented. Furthermore, the coverage of the tumor mass was optimized using the new method.

Post-chemotherapy target volumes are safe as boost volume for intact breast radiotherapy in locally advanced breast cancer

PURPOSE

The purpose of our study is to evaluate the challenges in identification of postoperative complexes (POC), the utility of clips in delineation of clinical target volume for boost in LABC downstaged with neoadjuvant chemotherapy (NACT) and to correlate this with patterns of recurrence.

METHODS AND MATERIALS

LABC patients who underwent NACT followed by BCS and radiotherapy (2007-2014) were the subject of our analysis. The data on visibility and characteristics of postoperative cavity (POC), concordance of its volume with clip volume on radiation planning scan were retrieved. A 1 cm margin beyond POC was delineated as a clinical target volume (CTV). Postoperative whole breast and supraclavicular radiotherapy (50 Gy/25fractions/5wk or 42.4 Gy/16#/3 wk) followed by boost (10-16 Gy/5-8#/1-1.5wk) were delivered. Patterns of recurrence were evaluated.

RESULTS

Out of 60 patients, 28.3% patients had stage II disease and 71.7% had stage III disease. 25% patients achieved pathological CR (complete response). The median POC volume was 30 cc and the median clip volume was 40 cc. The concordance of POC volume with clip volume was seen in 80%. Clips served as a good surrogate for POC in 80% of patients. At a median follow-up of 65 months (IQ range 32-84 months), and a lost to follow-up rate of 11.6 %, 3.3% (n = 2) patients had local recurrence (LR) and 8.3% (n = 5) had regional recurrence (LRR) in the supraclavicular region.

CONCLUSIONS

Delineation of post NACT excision cavity as POC for boost radiotherapy is safe. Clips serve as a good surrogate for CTV delineation in 75% patients.

Call for a Multidisciplinary Effort to Map the Lymphatic System with Advanced Medical Imaging Techniques: A Review of the Literature and Suggestions for Future Anatomical Research

This review intends to rekindle efforts to map the lymphatic system by using a more modern approach, based on medical imaging. The structure, function, and pathologies associated with the lymphatic system are first discussed to highlight the need for more accurately mapping the lymphatic system. Next, the need for an interdisciplinary approach, with a central role for the anatomist, to come up with better maps of the lymphatic system is emphasized. The current approaches on lymphatic system research involving medical imaging will be discussed and suggestions will be made for an all-encompassing effort to thoroughly map the entire lymphatic system. A first-hand account of our integration as anatomists in the radiotherapy department is given as an example of interdisciplinary collaboration. From this account, it will become clear that the interdisciplinary collaboration of anatomists in the clinical disciplines involved in lymphatic system research/treatment still holds great promise in terms of improving clinical regimens that are currently being employed. As such, we hope that our fellow anatomists will join us in an interdisciplinary effort to map the lymphatic system, because this could, in a relatively short timeframe, provide improved treatment options for patients with cancer or lymphatic pathologies all over the world. Anat Rec, 302:1681-1695, 2019. © 2019 American Association for Anatomy.

A heart atlas for breast radiation therapy and the influence of delination education on both intra and interobserver variability

PURPOSE

We developed a heart atlas for breast radiation therapy and evaluated the influence of education on intra and inter-observer similarity, and cardiac dose reporting.

MATERIALS AND METHODS

The data of 16 left breast cancer patients were analyzed. Eight observers delineated heart and cardiac subunits [left (LCA) and right (RCA) coronary arteries, left anterior descending artery (LAD), bilateral atrium and ventricles] before the education. A radiologist and radiation oncologist developed the atlas and delineated the gold standard (GS) volumes. Observers repeated the delineation after education. RT plans were made for pre/post-atlas contours. The similarity was assessed by Dice (DSC) and Jaccard (JSC) similarity coefficient indices. The absolute difference rate was calculated for the dose analysis.

RESULTS

The inter-observer similarity increased in heart and all subunits. The intra-observer similarity showed a heterogeneous distribution. The absolute difference rate in dose reporting was statistically significant for the bilateral atrium, right ventricle, LAD, LCA + LAD, RCA's maximum doses (p < 0.05). The maximum dose reporting differences from the GS decreased from 16.9 to 8.9% for LAD (p = 0.011); from 14.8 to 9.3% for LCA + LAD (p = 0.010).

CONCLUSION

The cardiac atlas reduces the intra-interobserver differences and improves dose reporting consistency. The first intra-observer similarity analysis was made in our study and revealed the need for repeated education to increase the consistency.

The use of new delineation tool "MIRADA" at the level of regional lymph nodes, step-by-step development and first results for early-stage breast cancer patients

OBJECTIVE:

To describe the practical procedure of implementation and optimization of delineation using "Mirada" software, as well as evaluation of the automatic segmentation for the daily practice of lymph nodes (LN) and organs at risk (OARs) in early stage breast cancer patients.

METHODS:

40 patients' CT scans in treatment position were selected and recontoured according to the European Society of Therapeutic Radiation Oncology guidelines. The atlas of data set was then created for automatic delineation. 30 patients with breast/chest wall and lymph nodes regions irradiated were recruited for evaluation. With the same treatment position, the CT scan images were acquired and then contoured by the MIRADA system automatically as well as by the radiation oncologist manually (as the reference). The conformity index (CI) was used to evaluate the concordance between both of them.

RESULTS:

The mean time for manual contour was 24.1 ± 5.1 and 26.4 ± 2.8 min for the LN and the OARs respectively. All the volumes of interest were contoured using the software (including corrections) in 30 min, which reduced the time of delineation of target volumes and OAR by about 40%. Of the 30 cases evaluated, the mean CI of 5 principal OARs showed ≥0.8. While the automatic contour of LN was less satisfactory with mean CI of 0.43 ± 0.1 (0.23-0.52).

CONCLUSION:

For the breast cancer patients, the studied software permitted to save time for delineation with acceptable OAR contours. The improvement of LN regions contour is needed. More cases and further evaluation are needed for the system to realize its routine use.

ADVANCES IN KNOWLEDGE:

It's the first description and evaluation of the automatic delineation and segmentation system for the breast cancer.

Short interactive workshops reduce variability in contouring treatment volumes for spine stereotactic body radiation therapy: Experience with the ESTRO FALCON programme and EduCase™ training tool

We report the results of 4, 2-h contouring workshops on target volume definition for spinal stereotactic radiotherapy. They combined traditional teaching methods with a web-based contouring/contour-analysis platform and led to a significant reduction in delineation variability. Short, interactive workshops can reduce interobserver variability in spine SBRT target volume delineation.

Variability in axillary lymph node delineation for breast cancer radiotherapy in presence of guidelines on a multi-institutional platform

AIM

To quantify the variability between radiation oncologists (ROs) when outlining axillary nodes in breast cancer.

MATERIAL AND METHODS

For each participating center, three ROs with different levels of expertise, i.e., junior (J), senior (S) and expert (E), contoured axillary nodal levels (L1, L2, L3 and L4) on the CT images of three different patients (P) of an increasing degree of anatomical complexity (from P1 to P2 to P3), according to contouring guidelines. Consensus contours were generated using the simultaneous truth and performance level estimation (STAPLE) method.

RESULTS

Fifteen centers and 42 ROs participated. Overall, the median Dice similarity coefficient was 0.66. Statistically significant differences were observed according to the level of expertise (better agreement for J and E, worse for S); the axillary level (better agreement for L1 and L4, worse for L3); the patient (better agreement for P1, worse for P3). Statistically significant differences in contouring were found in 18% of the inter-center comparison. Less than a half of the centers could claim to have a good agreement between the internal ROs.

CONCLUSIONS

The overall intra-institute and inter-institute agreement was moderate. Central lymph-node levels were the most critical and variability increased as the complexity of the patient's anatomy increased. These findings might have an effect on the interpretation of results from multicenter and even mono-institute studies.

Probabilistic liver atlas construction

BACKGROUND

Anatomical atlases are 3D volumes or shapes representing an organ or structure of the human body. They contain either the prototypical shape of the object of interest together with other shapes representing its statistical variations (statistical atlas) or a probability map of belonging to the object (probabilistic atlas). Probabilistic atlases are mostly built with simple estimations only involving the data at each spatial location.

RESULTS

A new method for probabilistic atlas construction that uses a generalized linear model is proposed. This method aims to improve the estimation of the probability to be covered by the liver. Furthermore, all methods to build an atlas involve previous coregistration of the sample of shapes available. The influence of the geometrical transformation adopted for registration in the quality of the final atlas has not been sufficiently investigated. The ability of an atlas to adapt to a new case is one of the most important quality criteria that should be taken into account. The presented experiments show that some methods for atlas construction are severely affected by the previous coregistration step.

CONCLUSION

We show the good performance of the new approach. Furthermore, results suggest that extremely flexible registration methods are not always beneficial, since they can reduce the variability of the atlas and hence its ability to give sensible values of probability when used as an aid in segmentation of new cases.

Recommendations from GEC ESTRO Breast Cancer Working Group (II): Target definition and target delineation for accelerated or boost partial breast irradiation using multicatheter interstitial brachytherapy after breast conserving open cavity surgery

OBJECTIVE

To prepare guidelines for target definition and delineations after open cavity breast conserving surgery in accelerated partial breast irradiations or boost treatments using multicatheter interstitial brachytherapy based on the consensus of the Breast Working Group of GEC-ESTRO.

METHOD

Following a study on interobserver variations of target volume delineation in multicatheter breast brachytherapy after open cavity surgery and a number of discussions in consensus meetings these guidelines were worked out by experts on the field.

PROPOSED RECOMMENDATIONS

(1) Consistent windowing has to be used for proper cavity visualization. (2) The cavity visualization score has to be at least 3 in order to minimize the interobserver variations of target definition. (3) At delineation of surgical cavity only the homogeneous part of the postoperative seroma has to be included in the contours and protrusions or sharp irregularities have to be excluded. When surgical clips are present, they have to be surrounded by the contour with close contact. (4) CTV is created from the outlined surgical cavity with a nonisotropic geometrical extension. In each direction the safety margin is calculated by taking into account the size of the free resection margin. The total size of safety margin is always 20mm which is the sum of the surgical and added safety margins. CTV is limited to chest wall/pectoral muscles and 5mm below the skin surface.

CONCLUSION

Following these guidelines the target volume definition in breast brachytherapy after open cavity surgery is expected to be accomplished in more consistent way with low interobserver variations.

Supraclavicular and infraclavicular lymph node delineation in breast cancer patients: a proposal deriving from a comparative study

AIMS AND BACKGROUND

Current advances in radiotherapy for breast cancer require knowledge of the anatomy of irradiated areas to minimize geographic miss and spare organs at risk. This study aimed at defining a contouring approach for supraclavicular (SC) and infraclavicular (IC) nodes after mastectomy or conservative surgery in patients with breast cancer.

METHODS AND STUDY DESIGN

In 15 patients, SC and IC nodes were contoured on computed tomography slices according to Madu et al and Dijkema et al. After analyzing relapse sites, as reported by Reed et al, our approach was defined. The 3 methods were compared in all patients, quantifying differences in contours by percentage overlap (PO).

RESULTS

In our approach, SC node delineation is similar to Madu et al in the ventral and medial landmarks, but includes the lateral SC nodes described by Dijkema et al. The lateral landmarks are the scalenus anterior and medius muscle lateral border and the clavicle. Dorsal boundaries are the scalenus anterior and medius muscle ventral and lateral surfaces and the subclavian artery ventral border. In IC node delineation, major differences emerged in cranial and dorsal limits which, in our approach, are the pectoralis minor muscle upper edge and the subclavian axillary artery ventral side. Our mean and median volumes and POs were between the other 2 methods.

CONCLUSIONS

This study contributes to standardizing draining node contouring, so as to reduce variability and minimize geographic miss.

Does ultrasound provide any added value in breast contouring for radiotherapy after conserving surgery for cancer?

BACKGROUND

Whole breast irradiation after conserving surgery for breast cancer requires precise definition of the target volume. The standard approach uses computed tomography (CT) images. However, since fatty breast and non-breast tissues have similar electronic densities, difficulties in differentiating between them hamper breast volume delineation. To overcome this limitation the breast contour is defined by palpation and then radio-opaque wire is put around it before the CT scan. To optimize assessment of breast margins in the cranial, caudal, medial, lateral and posterior directions, the present study evaluated palpation and CT and determined whether ultrasound (US) provided any added value.

METHODS

Twenty consecutive patients were enrolled after they had provided informed consent to participating in this prospective study which was approved by the Regional Public Health Ethics Committee. Palpation and US defined breast margins and each contour was marked and outlined with a fine plastic wire. Breasts were then contoured on axial CT images using the breast window width (WW) and window level (WL) (401 and 750 Hounsfield Units -HU- respectively), at which setting the plastic wires were invisible. Then, the lung window function (WW 1601 HU; WL -300 HU) was inserted to visualize the plastic wires which were used as guidelines to contour the palpable and US breast volumes. As each wire had a different diameter, both volumes were easily defined on CT slices. Results were analyzed using descriptive statistics, percentage overlap and reproducibility measures (agreement and reliability).

RESULTS

Volumes: US gave the largest and palpation the smallest. Agreement was best between palpation and CT. Reliability was almost perfect in all correlations. Extensions: Cranial and posterior were highest with US and smallest with palpation. Agreement was best between palpation and CT in all extensions except the cranial. Since strong to almost perfect agreement emerged for all comparisons, reliability was high.

CONCLUSIONS

US may be useful in defining the cranial and posterior extensions, mainly when tumours are localized there. This study demonstrates that the now standard radio-opaque wires around the palpable breast may not be needed in breast contouring.

[Prophylactic axillary radiotherapy for breast cancer]

Adjuvant radiotherapy, after breast conserving surgery or mastectomy for breast cancer, improves overall survival while decreasing the risk of recurrence. However, prophylactic postoperative radiotherapy of locoregional lymph nodes for breast cancer, particularly of the axillary region, is still controversial since the benefits and the risks due to axillary irradiation have not been well defined. To begin with, when performing conformal radiotherapy, volume definition is crucial for the analysis of the risk-benefit balance of any radiation treatment. Definition and contouring of the axillary lymph node region is discussed in this work, as per the recommendations of the European Society for Radiotherapy and Oncology (ESTRO). Axillary recurrences are rare, and the recent trend leads toward less aggressive surgery with regard to the axilla. In this literature review we present the data that lead us to avoid adjuvant axillary radiotherapy in pN0, pN0i+ and pN1mi patients even without axillary clearance and to perform it in some other situations. Finally, we propose an update about the potential toxicity of adjuvant axillary irradiation, which is essential for therapeutic decision-making based on current evidence, and to guide us in the evolution of our techniques and indications of axillary radiotherapy.

ESTRO consensus guideline on target volume delineation for elective radiation therapy of early stage breast cancer

BACKGROUND AND PURPOSE

Delineation of clinical target volumes (CTVs) is a weak link in radiation therapy (RT), and large inter-observer variation is seen in breast cancer patients. Several guidelines have been proposed, but most result in larger CTVs than based on conventional simulator-based RT. The aim was to develop a delineation guideline obtained by consensus between a broad European group of radiation oncologists.

MATERIAL AND METHODS

During ESTRO teaching courses on breast cancer, teachers sought consensus on delineation of CTV through dialogue based on cases. One teacher delineated CTV on CT scans of 2 patients, followed by discussion and adaptation of the delineation. The consensus established between teachers was sent to other teams working in the same field, both locally and on a national level, for their input. This was followed by developing a broad consensus based on discussions.

RESULTS

Borders of the CTV encompassing a 5mm margin around the large veins, running through the regional lymph node levels were agreed, and for the breast/thoracic wall other vessels were pointed out to guide delineation, with comments on margins for patients with advanced breast cancer.

CONCLUSION

The ESTRO consensus on CTV for elective RT of breast cancer, endorsed by a broad base of the radiation oncology community, is presented to improve consistency.

Helical tomotherapy for inoperable breast cancer: a new promising tool

BACKGROUND

We investigated the feasibility of helical tomotherapy (HT) for inoperable large breast tumors, after failing to achieve adequate treatment planning with conformal radiation techniques.

MATERIAL AND METHODS

Five consecutive patients with locally advanced breast cancer (LABC) were treated by preoperative HT. All patients received up-front chemotherapy before HT. Irradiated volumes included breast and nodal areas (45-50 Gy) in 4 patients. One patient received a simultaneous integrated boost (55 Gy) to gross tumor volume (GTV) without lymph node irradiation. Acute toxicity was assessed with Common Toxicity Criteria for Adverse Events v.4. Patients were evaluated for surgery at the end of treatment.

RESULTS

Patients were staged IIB to IIIC (according to the AJCC staging system 2010). HT was associated in 4 patients with concomitant chemotherapy (5-fluorouracil and vinorelbine). Two patients were scored with grade 3 skin toxicity (had not completed HT) and one with grade 3 febrile neutropenia. One patient stopped HT with grade 2 skin toxicity. All patients were able to undergo mastectomy at a median interval of 43 days (31-52) from HT. Pathological partial response was seen in all patients.

CONCLUSIONS

HT is feasible with acceptable toxicity profiles, potentially increased by chemotherapy. These preliminary results prompt us to consider a phase II study.

Creation of RTOG compliant patient CT-atlases for automated atlas based contouring of local regional breast and high-risk prostate cancers

Background

Increasing use of IMRT to treat breast and prostate cancers at high risk of regional nodal spread relies on accurate contouring of targets and organs at risk, which is subject to significant inter- and intra-observer variability. This study sought to evaluate the performance of an atlas based deformable registration algorithm to create multi-patient CT based atlases for automated contouring.

Methods

Breast and prostate multi-patient CT atlases (n = 50 and 14 respectively) were constructed to be consistent with RTOG consensus contouring guidelines. A commercially available software algorithm was evaluated by comparison of atlas-predicted contours against manual contours using Dice Similarity coefficients.

Results

High levels of agreement were demonstrated for prediction of OAR contours of lungs, heart, femurs, and minor editing required for the CTV breast/chest wall. CTVs generated for axillary nodes, supraclavicular nodes, prostate, and pelvic nodes demonstrated modest agreement. Small and highly variable structures, such as internal mammary nodes, lumpectomy cavity, rectum, penile bulb, and seminal vesicles had poor agreement.

Conclusions

A method to construct and validate performance of CT-based multi-patient atlases for automated atlas based auto-contouring has been demonstrated, and can be adopted for clinical use in planning of local regional breast and high-risk prostate radiotherapy.

Radiation therapy after breast-conserving surgery

SUMMARY Whole-breast irradiation in combination with breast-conserving surgery is a recognized standard alternative to mastectomy for the local treatment of early breast cancer. This article will review the evidence on the relationship of local control in the treated breast and survival, the indications of a boost dose to the tumor bed and the need for breast irradiation in ductal carcinoma in situ. Novel, shorter fractionation schemes allow the constraints of daily treatment courses over several weeks to be reduced, and recent technical improvements in treatment delivery will improve the results of treatment – in terms of local control and reduction of toxicity, and long-term sequelae. Research should focus on identifying molecular markers of radiation sensitivity and designing specific, targeted modulators of the radiation response in breast cancer.

Correlation of conventional and conformal plan parameters for predicting radiation pneumonitis in patients treated with breast cancer

PURPOSE

The purpose of this study is to evaluate the correlation between the conventional plan parameters and dosimetric parameters obtained from conformal radiotherapy (RT) planning, and between these parameters and radiation pneumontitis (RP) incidence.

METHODS

Clinical and dosimetric data of 122 patients that were treated with mastectomy and adjuvant 3D conformal RT (39% received 2-field RT [2-FRT], and in addition, 61% received 4-field RT [4-FRT]) were retrospectively analyzed. Central lung depth (CLD), maximum lung depth (MLD), and lung length were measured by the conventional plan. Lung dose-volume histograms (DVH) were created with conformal planning, and the lung volumes receiving 5 to 50 Gy (V(5Gy) to V(50Gy)) were calculated. Minimum (D(min)), maximum (D(max)), and mean doses (D(mean)) for the ipsilateral lung and bilateral lungs were measured by DVH. Correlations between 3D dosimetric data and 2D radiographic parameters were analyzed.

RESULTS

The conventional plan parameters did not significantly differ between 2-FRT and 4-FRT. The conformal plan D(min), D(max), and D(mean) values were higher in 4-FRT versus 2-FRT. CLD and MLD were correlated with DVH parameter V(5Gy) to V(45Gy) values for ipsilateral, as well as bilateral lungs for 2-FRT. MLD and ipsilateral D(mean) via 2-FRT planning had the strongest positive correlation (r=0.76, p<0.01). Moderate correlations existed between CLD and ipsilateral and bilateral lung V(5Gy-45Gy), and between MLD and bilateral lung V(5Gy-45Gy) values in 2-FRT. Only four patients developed symptomatic RP, 4 with 4-FRT and one with 2-FRT.

CONCLUSION

The conformal plan parameters were strongly correlated with dose-volume parameters for breast 2-FRT. With only 4 cases of Grade 3 RP observed, our study is limited in its ability to provide definitive guidance, however assuming that CLD is an indicator for RP, V(20Gy) could be used as a predictor for RP and for 2-FRT. A well-defined parameters are still required to predict RP in 4-FRT.

[Organs at risk and target volumes: definition for conformal radiation therapy in breast cancer]

Adjuvant radiotherapy is a standard component of breast cancer treatment. The addition of radiotherapy after breast conserving surgery has been shown to reduce local recurrence rate and improve long-term survival. Accurate delineation of target volumes and organs at risk is crucial to the quality of treatment planning and delivered accomplished with innovate technologies in radiation therapy. This allows the radiation beam to be shaped specifically to each individual patient's anatomy. Target volumes include the mammary gland and surgical bed in case of breast conserving surgery, the chest wall in case of mastectomy, and if indicated, regional lymph nodes (axillary, supra- and infraclavicular and internal mammary). Organs at risk include lungs, thyroid, brachial plexus, heart, spinal cord and oesophagus. The aim of this article is to encourage the use of conformal treatment and delineation of target volumes and organs at risk and to describe specifically the definition of these volumes.

[Axillary lymph node irradiation in breast cancer: state of the art]

Place of axillary radiotherapy in the management of patients with breast cancer remains debated. While the prognostic value of axillary lymph node extension has been largely demonstrated, the benefit of axillary treatment is more uncertain. Large clinical trials having demonstrated the benefit of adjuvant radiotherapy in advanced breast cancer comprised large nodal irradiation, including axillary area. Analyzing the true benefit of axillary radiotherapy is rendered difficult by heterogeneity of series, particularly when focusing on the extent of lymph node dissection. Although adjuvant axillary radiotherapy is usually recommended in patients with insufficient lymph node dissection or with bulky axillary involvement, the prognosis in these patients remains poor by metastatic evolution and such strategy exposes to increased toxicity and functional sequels. Further assessments should better define the optimal indications and the true benefit of axillary radiotherapy.

Human-computer interaction in radiotherapy target volume delineation: a prospective, multi-institutional comparison of user input devices

The purpose of this study was the prospective comparison of objective and subjective effects of target volume region of interest (ROI) delineation using mouse-keyboard and pen-tablet user input devices (UIDs). The study was designed as a prospective test/retest sequence, with Wilcoxon signed rank test for matched-pair comparison. Twenty-one physician-observers contoured target volume ROIs on four standardized cases (representative of brain, prostate, lung, and head and neck malignancies) twice: once using QWERTY keyboard/scroll-wheel mouse UID and once with pen-tablet UID (DTX2100, Wacom Technology Corporation, Vancouver, WA, USA). Active task time, ROI manipulation task data, and subjective survey data were collected. One hundred twenty-nine target volume ROI sets were collected, with 62 paired pen-tablet/mouse-keyboard sessions. Active contouring time was reduced using the pen-tablet UID, with mean ± SD active contouring time of 26 ± 23 min, compared with 32 ± 25 with the mouse (p ≤ 0.01). Subjective estimation of time spent was also reduced from 31 ± 26 with mouse to 27 ± 22 min with the pen (p = 0.02). Task analysis showed ROI correction task reduction (p = 0.045) and decreased panning and scrolling tasks (p < 0.01) with the pen-tablet; drawing, window/level changes, and zoom commands were unchanged (p = n.s.) Volumetric analysis demonstrated no detectable differences in ROI volume nor intra- or inter-observer volumetric coverage. Fifty-two of 62 (84%) users preferred the tablet for each contouring task; 5 of 62 (8%) denoted no preference, and 5 of 62 (8%) chose the mouse interface. The pen-tablet UID reduced active contouring time and reduced correction of ROIs, without substantially altering ROI volume/coverage.

Critical discussion of evaluation parameters for inter-observer variability in target definition for radiation therapy

BACKGROUND AND PURPOSE

Inter-observer studies represent a valid method for the evaluation of target definition uncertainties and contouring guidelines. However, data from the literature do not yet give clear guidelines for reporting contouring variability. Thus, the purpose of this work was to compare and discuss various methods to determine variability on the basis of clinical cases and a literature review.

PATIENTS AND METHODS

In this study, 7 prostate and 8 lung cases were contoured on CT images by 8 experienced observers. Analysis of variability included descriptive statistics, calculation of overlap measures, and statistical measures of agreement. Cross tables with ratios and correlations were established for overlap parameters.

RESULTS

It was shown that the minimal set of parameters to be reported should include at least one of three volume overlap measures (i.e., generalized conformity index, Jaccard coefficient, or conformation number). High correlation between these parameters and scatter of the results was observed.

CONCLUSION

A combination of descriptive statistics, overlap measure, and statistical measure of agreement or reliability analysis is required to fully report the interrater variability in delineation.

Can we decrease the skin reaction in breast cancer patients using hyaluronic acid during radiation therapy? Results of phase III randomised trial

PURPOSE

Radio-induced early skin reactions still remain a clinical challenge. Preliminary results with Hyaluronic acid, one of the most recent topical products used in this indication are proving interesting. To evaluate the efficacy of Hyaluronic acid compared to placebo.

MATERIAL AND METHODS

Breast cancer patients with grade 1-2 radio-induced dermatitis during postoperative radiotherapy were eligible. They were randomised to receive either hyaluronic acid (A) or a simple emollient (B). The primary endpoint was the clinical evaluation of the erythema (success versus failure). Secondary endpoints were the evaluation of skin colorimetry, pain, and quality of life.

RESULTS

Two-hundred patients were enrolled (A=99, B=101). Ninety-five patients per treatment arm could be evaluated. Failures occurred in 23 patients (24%) in the hyaluronic acid arm, and 32 (34%) in the emollient arm (p=0.15). Seventy-three patients (36.5%) prematurely stopped the treatment without any ensuing difference between the two arms. Body mass index and the size of the epithelitis were both independently associated with the failure of the local treatment. The relative reduction of colorimetric levels was 20% in the hyaluronic acid group, and 13% in the emollient group (p=0.46). Concerning the quality of life assessment, there was a trend towards a lower level of pain in patients receiving hyaluronic acid (p=0.053).

CONCLUSIONS

The present study showed no significant difference between hyaluronic acid and simple emollient in the treatment of acute radio-induced dermatitis. There was however a trend towards an improvement in both pain level and skin colorimetry.

[Radiotherapy for breast cancer and pacemaker]

PURPOSE

Patients with permanent cardiac pacemakers occasionally require radiotherapy. Therapeutic irradiation may cause pacemakers to malfunction due to the effects of ionizing radiation or electromagnetic interference. We studied the breast cancer patients who needed breast and/or chest wall and lymph node irradiation to assess the feasibility and tolerance in this population of patients.

PATIENTS AND METHODS

From November 2008 to December 2009, more than 900 patients received radiotherapy for their breast cancer in our department using megavoltage linear accelerator (X 4-6 MV and electrons). Among them, seven patients were with permanent pacemaker. All patients have been treated to the breast and chest wall and/or lymph nodes. Total dose to breast and/or chest wall was 50 Gy/25 fractions and 46 Gy/23 fractions to lymph nodes. Patients who underwent conserving surgery followed by breast irradiation were boosted when indicated to tumour bed with 16 Gy/8 fractions. All patients were monitored everyday in presence of radiation oncologist to follow the function of their pacemaker. All pacemakers were controlled before and after radiotherapy by the patients' cardiologist.

RESULTS

Seven patients were referred in our department for postoperative breast cancer radiotherapy. Among them, only one patient was declined for radiotherapy and underwent mastectomy without radiotherapy. In four cases the pacemaker was repositioned before the beginning of radiotherapy. Six patients, aged between 48 and 84 years underwent irradiation for their breast cancer. Four patients were treated with conserving surgery followed by breast radiotherapy and two with mastectomy followed by chest wall and internal mammary chain, supra- and infra-clavicular lymph node irradiation. The dose to the pacemaker generator was kept below 2 Gy. There was no pacemaker dysfunction observed during the radiotherapy.

CONCLUSION

The multidisciplinary work with position change of the pacemaker before radiotherapy and everyday monitoring permitted the safe treatment of our patients. Updated guidelines are definitely needed with more details about acceptable doses at the different parts of the pacemaker.

Cardiac toxicity in breast cancer patients: from a fractional point of view to a global assessment

When focusing on heart disease, most available studies split the two different parts of the adjuvant treatment, i.e., systemic therapies and radiation therapy, making it difficult to implement efficient strategies for preventing treatment-induced cardiac toxicity. This paper reviews the current understanding of treatments-induced cardiac toxicity in a global approach. Many factors should be considered when assessing the cardiac hazard. Treatment-related risk factors include heart dose exposure, chemotherapy, targeted agents such as HER2 inhibitors, but also endocrine agents, or anesthetic procedure. Patients' characteristics should also be taken into account. Age, menopausal status, stress, previous history of cardiac disease, genetic profile, and body mass index could all impact on cardiac function after adjuvant therapies. Cardiac toxicity should not be analyzed as the consequence of a specific therapy, but should be considered as the result of additive or supra-additive toxicities. By this way, it will be possible to implement new strategies for preventing treatment-induced cardiac toxicity.

The acute skin and heart toxicity of a concurrent association of trastuzumab and locoregional breast radiotherapy including internal mammary chain: a single-institution study

BACKGROUND

To evaluate the skin and heart toxicity of a concurrent adjuvant trastuzumab-radiotherapy for breast cancer (BC), especially in the case of internal mammary chain (IMC) irradiation.

MATERIAL AND METHODS

Prospective study of 106 patients treated between 06/2003 and 03/2007 by concurrent trastuzumab-radiotherapy for non-metastatic BC. Left ventricular ejection fractions (LVEF) was assessed at baseline, before and after radiotherapy and then every 4-6 months. All toxicities were evaluated using CTCAEV3.

RESULTS

Median age was 52 years (25-76). Chemotherapy with anthracycline was administered in 92% of patients. All patients received trastuzumab every three weeks (8 mg/kg followed by 6 mg/kg) for a median duration of 12 months (3-40). The IMC was irradiated in 83% of patients. There were: 87 grade 1, 14 grade 2 and 2 grade 3 skin reactions. There were 13 oesophagitis: 9 grade 1; 3 grade 2, and 1 grade 3. Out of 101 patients with assessments after 6 months, late telangiectasia grade 1 occurred in 5 patients, local pain grade 1 in 19 patients and grade 2 in 3 patients, fibrosis grade 1 in 16 patients. A reversible grade ≥2 left ventricular systolic dysfunction occurred in 6 patients.

CONCLUSION

In this prospective study of breast cancer patients treated with trastuzumab-radiotherapy with, in most cases, anthracycline-based chemotherapy and IMC irradiation, both the rate of abnormal LVEF after concurrent trastuzumab-radiotherapy and the skin toxicity were deemed acceptable. Further follow-up is needed.

Recent advances in breast cancer radiotherapy: Evolution or revolution, or how to decrease cardiac toxicity?

Radiation therapy has a major role in the management of breast cancers. However, there is no consensus on how to irradiate and on volume definitions, and there are strong differences in strategies according to different centers and physicians. New treatment protocols and techniques have been used with the principal purpose of decreasing lung and heart toxicity and adapting radiation treatment to patients’ anatomy. There is evidence that indicates internal mammary chain radiotherapy should be used carefully and that high quality techniques should be used for decreasing the dose delivered to the heart. This review of the literature presents the state of the art on breast cancer radiotherapy, with special focus on the indications, techniques, and potential toxicity.

Simplified rules for everyday delineation of lymph node areas for breast cancer radiotherapy

The aim of this study was to present the simplified rules of delineation of lymph node (LN) volumes in breast irradiation. Practical rules of delineation of LN areas were developed in the Department of Radiation Oncology of the Institut Curie. These practical guidelines of delineation were based on different specific publications in the field of breast and LN anatomy. The principal characteristic of these rules is their clearly established relationship with anatomical structure, which is easy to find on CT slices. The simplified rules of delineation have been published in pocket format as the illustrated atlas "Help of delineation for breast cancer treatment". In this small pocket guide, delineation using the practical rules is illustrated, with examples from anatomical CT slices. It is shown that there is an improvement in delineation after the use of these simplified rules and the guide. In conclusion, this small guide is useful for improving everyday practice and decreasing the differences in target delineation for breast irradiation between institutions and observers.

[Monocentric evaluation of the skin and cardiac toxicities of the concomitant administration of trastuzumab and radiotherapy]

PURPOSE

Prospective monocentric study of the skin and heart tolerance of a concurrent administration of trastuzumab (T) and radiotherapy (RT) for breast cancer (BC).

PATIENTS AND METHODS

From February 2004 to January 2007, 57 patients (pts), were treated by a concomitant administration of T and normo-fractionated RT of either whole breast (+/-boost) or chest. The perfusion of T started either with or after chemotherapy (CT). Left ventricular ejection fractions (LEVF), assessed at baseline, before start of RT, after completion of RT and then every four to six months with either echocardiography or multiple gated acquisition scanning, were considered normal if greater or equal to 50% or stated so by the cardiologist. Inclusion criteria included a normal LVEF at baseline. Skin toxicity was evaluated using CTCAEV3. Median age was 49 years (25-80). CT with anthracycline was administered in 84% (total dose 300 mg/m(2)). All but one patient (treated weekly) received T every three weeks (8 mg/kg followed by 6 mg/kg) for a median duration of 12 months (6-33). The internal mammary chain was irradiated in 88% of cases. Median follow-up for LVEF assessment was 13 months (2-33).

RESULTS

LVEF at pre-RT were normal in 54 pts (100%, three Missing Data [MD]), at post-RT in 56 pts (98%, no MD) and at last follow-up in 53 pts (95%, one MD). There were two grade 0, 44 grade I and 11 grade II skin reactions. For the 27 patients with a skin toxicity assessment after six months, late skin toxicity was grade 0 in 22 pts, grade 1 in four, grade 2 in one.

CONCLUSION

Provided that the technique is adapted, the acute skin and heart toxicities of the concomitant administration of T-RT appeared satisfactory. More patients and longer follow-up are still mandatory.