Contouring consensus guidelines in breast cancer radiotherapy: Comparison and systematic review of patterns of failure

Examining the impact of the device used for contouring in saving time and increasing the ease of contouring patients in radiotherapy treatment

INTRODUCTION/BACKGROUND

This study was designed to investigate the amount of time saved and the degree of contour difficulty between the two methods of contouring, mouse/keyboard, versus touch screen/stylus in radiotherapy.

METHODS

Each of 94 patients consisting of 26 breast cancer cases, 24 lymph nodes cases, 25 rectal cancer cases, and 19 heart cases has been contoured twice. One with a mouse/keyboard, and the next one with the touch screen/stylus. Three radiation oncologists participated in this study. Contouring information including measured time, estimated time spent, volume of contour performed and organ contoured are recorded. To evaluate the differences between the contouring methods, the results regarding target volume and time to completion were analyzed using two-way robust ANOVA. Ease of use and contouring difficulty were compared for differences in distribution of the response choices between the groups using Pearson chi-square test.

RESULTS

In this study, 94 clinical cases were studied. The average time required for contouring with the touch screen/stylus method was half the time needed for contouring patients with the mouse/keyboard method. The reduction in the time in breast cancer cases was the highest (48.2%) and the lowest in head and neck cancer cases (32.4%). In comparing the contoured volumes, no significant difference was observed between the two methods. the mean estimated time reported by the radiation oncologist in the mouse/keyboard method was 5.6 minutes longer and, in the touch screen/stylus method, was 3.9 minutes less than the actual measured time.

CONCLUSIONS

All the measured and analyzed variables show the superiority of contouring with the touch screen/stylus method and reduced the time required for patient contouring by an average of 50%.

Comparative Study of Plan Robustness for Breast Radiotherapy: Volumetric Modulated Arc Therapy Plans with Robust Optimization versus Manual Flash Approach

A previous study investigated robustness of manual flash (MF) and robust optimized (RO) volumetric modulated arc therapy plans for breast radiotherapy based on five patients in 2020 and indicated that the RO was more robust than the MF, although the MF is still current standard practice. The purpose of this study was to compare their plan robustness in terms of dose variation to clinical target volume (CTV) and organs at risk (OARs) based on a larger sample size. This was a retrospective study involving 34 female patients. Their plan robustness was evaluated based on measured volume/dose difference between nominal and worst scenarios (ΔV/ΔD) for each CTV and OARs parameter, with a smaller difference representing greater robustness. Paired sample t-test was used to compare their robustness values. All parameters (except CTV ΔD98%) of the RO approach had smaller ΔV/ΔD values than those of the MF. Also, the RO approach had statistically significantly smaller ΔV/ΔD values (p < 0.001-0.012) for all CTV parameters except the CTV ΔV95% and ΔD98% and heart ΔDmean. This study's results confirm that the RO approach was more robust than the MF in general. Although both techniques were able to generate clinically acceptable plans for breast radiotherapy, the RO could potentially improve workflow efficiency due to its simpler planning process.

Summary of Cardiac Computed Tomographic Imaging in Cardio-Oncology: An Expert Consensus Document of the Society of Cardiovascular Computed Tomography

PURPOSE

The purpose of this document is to develop a summary of recommendations from the "Cardiac Computed Tomographic Imaging in Cardio-Oncology: An Expert Consensus Document of the Society of Cardiovascular Computed Tomography (SCCT)" document and provide commentary on key recommendations that are relevant to radiation oncology.

METHODS

In July 2019, the SCCT convened a multidisciplinary panel of experts to develop a consensus document based on a literature search and a formal consensus process, which was separately published in 2022. A new panel consisting of the radiation oncologist from the original guideline and additional radiation oncologists was formed to address SCCT recommendations and their implications for radiation oncology.

SUMMARY

The SCCT consensus document included 6 core sections. Two of these sections were identified as particularly relevant to radiation oncologists. These include evaluation of shared risk factors and role of cardiac computed tomography in risk stratification of patients with cancer (section 1) and the role of cardiac computed tomography in the evaluation of the effects of radiation therapy (section 4). These recommendations are summarized, with additional commentary on the role of radiation oncologists as individual practitioners and radiation oncology practices as a whole in evaluation of coronary artery calcifications on computed tomography images; assessment of the effects of radiation therapy on cardiovascular risk after treatment; and management of patients at elevated risk of cardiovascular sequelae of treatment. Radiation oncologists should be aware of the recommendations in the SCCT consensus document and consider those elements that relate to their practice. This summary document calls attention to the key roles and limitations of radiation oncologists and radiation oncology practices in managing cardiotoxicity risk and highlights the need for ongoing study on the effects of radiation therapy on the heart, cardiac substructures, and long-term risk of cardiotoxicity related to treatment.

Impact of Imaging Biomarkers and AI on Breast Cancer Management: A Brief Review

Breast cancer stands out as the most frequently identified malignancy, ranking as the fifth leading cause of global cancer-related deaths. The American College of Radiology (ACR) introduced the Breast Imaging Reporting and Data System (BI-RADS) as a standard terminology facilitating communication between radiologists and clinicians; however, an update is now imperative to encompass the latest imaging modalities developed subsequent to the 5th edition of BI-RADS. Within this review article, we provide a concise history of BI-RADS, delve into advanced mammography techniques, ultrasonography (US), magnetic resonance imaging (MRI), PET/CT images, and microwave breast imaging, and subsequently furnish comprehensive, updated insights into Molecular Breast Imaging (MBI), diagnostic imaging biomarkers, and the assessment of treatment responses. This endeavor aims to enhance radiologists' proficiency in catering to the personalized needs of breast cancer patients. Lastly, we explore the augmented benefits of artificial intelligence (AI), machine learning (ML), and deep learning (DL) applications in segmenting, detecting, and diagnosing breast cancer, as well as the early prediction of the response of tumors to neoadjuvant chemotherapy (NAC). By assimilating state-of-the-art computer algorithms capable of deciphering intricate imaging data and aiding radiologists in rendering precise and effective diagnoses, AI has profoundly revolutionized the landscape of breast cancer radiology. Its vast potential holds the promise of bolstering radiologists' capabilities and ameliorating patient outcomes in the realm of breast cancer management.

Individualized Clinical Target Volume for Irradiation of the Supraclavicular Region in Breast Cancer Based on Mapping of the Involved Ipsilateral Supraclavicular Lymph Nodes

PURPOSE

To map supraclavicular fossa-involved lymph nodes (SCF-LNs) in patients with nonmetastatic breast cancer, evaluate the coverage of widely adopted atlases, and propose modified borders for individualized regional irradiation.

METHODS AND MATERIALS

M0 patients with biopsy-proven SCF-LNs who were SCF treatment-naïve were included. The SCF was spatially divided into subregions, with each node mapped on the original images. The geographic misses after the borders of multiple atlases were evaluated and factors affecting SCF-LNs' spread pattern were analyzed.

RESULTS

From 1998 to 2022, 209 patients with 1242 SCF-LNs were eligible. Patients had a median of 4 nodes. At least 537 nodes (43.2%) in 147 patients (70.3%) were lateral to the sternocleidomastoid muscle (SCM), and 403 nodes (32.4%) in 127 patients (60.8%) were dorsal to the anterior scalene muscle (ASM). In the 88 patients with ≤3 SCF-LNs, at least 66 nodes (39.1%) in 40 patients (45.5%) were lateral to the SCM, and 34 nodes (20.1%) in 29 patients (33.0%) were dorsal to the ASM. These nodes were not covered by the Radiation Therapy Oncology Group (RTOG) atlas and partly within the Radiotherapy Comparative Effectiveness atlas. One hundred four patients (49.8%) had 432 SCF-LNs (34.8%) beyond the upper border of the European Society for Radiotherapy and Oncology (ESTRO) atlas. In multivariate regression, nodal sizes were associated with wider spread in the primary group. Being triple-negative (TN) subtype was associated with less spread in the recurrent group. Situation-based clinical target volumes (CTVs) were theorized, in which for a sequential spread, the posterior border could be the posterior scalene muscle or even be more constringent; otherwise, it should touch the anterior trapezius surface.

CONCLUSIONS

SCF-LNs tend to spread laterally and dorsally beyond the RTOG borders, even in M0 stages with ≤3 SCF-LNs. The ESTRO upper border does not guarantee coverage with multiple SCF-LNs. Nodal burden and non-TN types are predictive of wider dissemination. A situation-based CTV is possibly feasible. Deciphering the SCF-LN spread route is needed.

Right versus left breast radiation and coronary artery disease: is there a differential?

There is literature supporting the view that chest radiation (CR) for the management of primary or metastatic cancer of the mediastinum and chest, including breast cancer is associated with all types of heart disease, including coronary artery disease (CAD), manifesting during long-term follow-up. This review explores the literature about the association of CR for the management of cancer and CAD, particularly focussing on breast cancer, and further on the differential between CR for right versus left breast cancer. The balk of the literature suggests that there is higher incidence of CAD in patients undergoing left versus right-CR for breast cancer, and that cardiologists and oncologists need to become involved systematically in their assessment prior to CR and at subsequent follow-up.

Mapping of PET/CT-based regional nodes distribution of recurrent/advanced breast cancer and comparison with current delineation atlas

OBJECTIVE

To localize the distribution of regional nodes in recurrent/advanced breast cancer patients based on 18-fludeoxyglucose (FDG) positron emission tomography/CT (PET/CT) images and validate the coverage of clinical target volumes (CTVs) for regional nodes with current contouring guidelines.

METHODS

We enrolled 154 recurrent/advanced breast cancer patients with FDG-avid regional nodes who underwent PET/CT between January 2018 and June 2020. Involvement of lymph node regions including axillary lymph node level I-III (ALN-I, ALN-II, ALN-III), Rotter's nodes (RN), medial supraclavicular (SC-M), lateral supraclavicular (SC-L) and internal mammary nodes (IMN) was recorded respectively. Coverage of the CTVs in different atlases and the locations of out-of-field were evaluated.

RESULTS

A total of 348 lymph node regions containing disease were identified, including ALN-I 109, ALN-II 46, ALN-III 36, RN 17, SC-M 68, SC-L 36 and IMN 36. Recurrent ALNs mainly located cranially and ventrally to the axillary vein (AV). Ipsilateral cervical nodes were simultaneously affected in 33/76 SC positive patients. RADCOMP (306/348) and RUIJIN (291/348) guidelines had higher coverage compared with RTOG (205/348) and ESTRO (202/348) guidelines (p < 0.001, respectively). In primary non-metastastic and recurrent patients, major missings located in SC-L (7/7, 17/17) and IMN (7/10, 15/19) for RTOG guideline while SC-L (7/7, 17/17) for ESTRO guideline (p < 0.001, respectively). Among recurrent patients, SC-M (22/31) was another major missing area for ESTRO guideline (p < 0.001).

CONCLUSION

The current guidelines effectively cover most regional nodes in postoperative breast cancer patients. SC-L and IMN were the major missing regions. Recurrent ALNs were most often seen in cranial and ventral to the AV. The CTV of patients with clinically positive SC was recommended to extend up to the hyoid level. The CTVs should be adjusted based on risks of recurrence individually.

ADVANCES IN KNOWLEDGE

The difference of regional nodes delineation between current guidelines mainly located in SC and IMN regions. High axilla including subclavicular nodes and the RN above AV for recurrent patients and the region between cricoid and hyoid for positive SC patients should be meticulously contoured.

Evaluation of apical clips placed during axillary dissection demonstrates potential under-coverage of axillary radiation therapy target volumes during breast cancer regional nodal irradiation

INTRODUCTION

Evidence-based Australian guidelines (eviQ) recommend adjuvant supraclavicular fossa irradiation after axillary lymph node dissection (ALND) in node-positive breast cancer patients. Disparity between surgically determined versus computed tomography (CT) determined nodal volumes may result in discontiguous nodal volumes and untreated nodal tissue. We examine the extent of untreated nodal tissue in women with breast cancer post-level II or III ALND and adjuvant radiation therapy (RT) using ESTRO contouring guidelines.

METHODS

Female breast cancer patients who underwent level II and III ALND with apical clip placement from 2016 to 2020 and CT simulated in supine position were included. CT-defined axillary level II-IV volumes were contoured using ESTRO guidelines. The distance between the apical clip and RT nodal volumes was measured to indicate extent of untreated tissue.

RESULTS

Of 34 eligible patients treated by 7 surgeons, 76% had level II ALND and 24% level III ALND. Only 5.9% of clips entirely encompassed the corresponding RT nodal volumes. 55.9% of clips fell within and 44.1% fell inferolaterally outside the corresponding RT nodal volumes. A median 3.6 cm (range 0-7.5 cm) of undissected nodal tissue would not be included within standard RT target volumes following eviQ recommendations.

CONCLUSION

There is a disparity between surgically determined versus CT determined axillary nodal volumes, leading to discontiguous nodal volumes and untreated axillary nodal tissue, despite following standard radiation contouring guidelines. Intraoperatively placed apical axillary clips may assist radiation oncologists to accurately delineate undissected nodal tissues at risk.

An Underestimated Toxicity Radiation-Induced Hypothyroidism in Patients Multimodally Treated for Breast Cancer

Radiation therapy is part of the therapeutic arsenal for breast cancer, whether it is adjuvant treatment after lumpectomy or radical mastectomy, or it is used as a palliative option in the case of metastatic or recurrent disease. Significant advances in diagnostic and therapeutic stratification of breast cancers have significantly prolonged survival, even in the metastatic stage. Exposure of patients during the course of the disease in a multidisciplinary therapeutic approach including chemotherapy, hormone therapy, targeted anti-HER therapies or CDK4/6 inhibitors had led to improved survival but with the price of additional toxicity. Among them, hypothyroidism is a well-known consequence of external radiation therapy, especially in the case of cervical region irradiation, including supraclavicular and infra-clavicular nodal levels. In this situation, the thyroid gland is considered as an organ at risk (OAR) and receives a significant dose of radiation. Subclinical hypothyroidism is a common endocrine disorder characterized by elevated TSH levels with normal levels of FT4 (free T4) and FT3 (free T3), and as a late effect, primary hypothyroidism is one of the late effects that significantly affects the quality of life for patients with breast cancer receiving multimodal treatment. Hypothyroidism has a significant impact on quality of life, most often occurring as late clinical toxicity, secondary to thyroid irradiation at doses between 30 and 70 Gy. Dose-volume parameters of irradiation, gland function at the beginning of the treatment and associated systemic therapies may be factors that alter thyroid radio-sensitivity and affect thyroid gland tolerance. In the case of head and neck tumor pathology, in which doses of >50 Gy are routinely used, the thyroid gland is generally considered as an OAR, the rate of radio-induced hypothyroidism being estimated at rates of between 20% and 52%. For breast cancer, the thyroid is often neglected in terms of dosimetry protection, the rate of late dysfunction being 6–21%.

Impact of respiratory motion in dosimetric and clinical advantages for adjuvant left-sided breast radiotherapy

We investigated the organ-sparing effect of the deep inspiration breath hold (DIBH) technique among different levels of lung expansion for left-side breast radiotherapy. This retrospective study enrolled 30 patients who received adjuvant left breast radiotherapy after breast-conserving surgery (BCS). Simulation scans of both DIBH and deep breathing four-dimensional computed tomography (4DCT) were acquired, and three treatment plans were generated for each patient. One plan was based on the DIBH images, and the other two plans were based on the mid-lung expansion (ME) and initial lung expansion (IE) phases retrieved from 4DCT data sets. Dosimetric comparisons and normal tissue complication probability (NTCP) models were conducted. We used image registration for displacement analysis and sought potential factors related to the dose benefit of DIBH. The DIBH plans resulted significantly lower doses to the heart, left ventricle (LV) and left anterior descending coronary artery (LAD), including the high- to low-dose areas, followed by the ME plans and IE plans (p < 0.05). DIBH reduced the risk of long-term cardiac mortality by 40% and radiation pneumonitis of the left lung by 37.96% compared with the IE plans (p < 0.001). The reduction in the mean dose to the heart and LV significantly correlated with anterior displacement of the left lung. The DIBH technique is a feasible tool to provide dosimetric and clinical advantages for adjuvant left-sided breast radiotherapy. Breathing pattern and the level of lung expansion seem to play an important role.

Computed tomography-guided partial-breast brachytherapy using implanted catheters as fiducial markers versus co-registered magnetic resonance imaging

PURPOSE

Partial-breast irradiation (PBI) needs accurate cavity delineation with computed tomography (CT). In perioperative PBI using multicatheter-interstitial brachytherapy (MIB), catheters implanted during surgery were enabled as fiducial markers. Magnetic resonance imaging (MRI) can also assist delineation with CT.

METHODS

Patients receiving MIB-PBI were analyzed. Cavity visualization scores (CVSs) were categorized with CT. With catheter-based delineation (CBD), the relationship between cavity boundaries and catheters were used to contour the tumor bed. Co-registered MRI delineation (CMD) was also performed. The correlation between cavity volume and the excised tissue weight was compared for the two techniques.

RESULTS

The association between CVS and preoperative characteristics in 159 patients showed mammographic breast density (MBD) remained correlated to CVS on multiple regression analyses; CVS = 5.2-0.61 x MBD (p < 0.0001). In 43 patients, the cavity volumes determined with CBD vs CMD were 12.8 ± 6.4 cm³ vs 16.1 ± 12.4 cm³ (p < 0.0001), and their plots with excised weights showed the best fitting lines were 0.29 vs 0.48 (p < 0.0001), respectively. The correlation coefficients for CBD vs CMD were 0.65 vs 0.55 (p = 0.20) in low (CVS 1-3, n = 27) and 0.72 vs 0.58 (p = 0.36) in high visualized cavities (CVS 4-5, n = 16), respectively.

CONCLUSIONS

The use of implanted catheters as fiducial markers was associated with smaller cavities and greater correlations with the excised tissue weights than co-registration with MRI. This might be a useful technique, especially for patients with dense breasts on mammography.

Past, Present, and Future of Radiation-Induced Cardiotoxicity: Refinements in Targeting, Surveillance, and Risk Stratification

Radiation therapy is an important component of cancer therapy for many malignancies. With improvements in cardiac-sparing techniques, radiation-induced cardiac dysfunction has decreased but remains a continued concern. In this review, we provide an overview of the evolution of radiotherapy techniques in thoracic cancers and associated reductions in cardiac risk. We also highlight data demonstrating that in some cases radiation doses to specific cardiac substructures correlate with cardiac toxicities and/or survival beyond mean heart dose alone. Advanced cardiac imaging, cardiovascular risk assessment, and potentially even biomarkers can help guide post-radiotherapy patient care. In addition, treatment of ventricular arrhythmias with the use of ablative radiotherapy may inform knowledge of radiation-induced cardiac dysfunction. Future efforts should explore further personalization of radiotherapy to minimize cardiac dysfunction by coupling knowledge derived from enhanced dosimetry to cardiac substructures, post-radiation regional dysfunction seen on advanced cardiac imaging, and more complete cardiac toxicity data.

Locally Advanced Breast Cancer: Treatment Patterns and Predictors of Survival in a Saudi Tertiary Center

Background  Breast cancer (BC) is the most common cancer in the Kingdom of Saudi Arabia (KSA) and the second leading cause of cancer-related mortality. About 40% of BC in KSA is locally advanced BC (LABC), which has been associated with poorer survival compared with early diagnosed BC. Objective To review the presentation and outcomes of LABC, including the characteristics of the disease, different treatment modalities, overall survival (OS), disease-free survival (DFS), and local recurrence in relation to different radiotherapy (RT) techniques. Methods  We retrospectively reviewed the medical records of 153 female patients with pathologically proven LABC diagnosed at King Abdulaziz University Hospital, Jeddah, KSA, between 2009 and 2017. We obtained data on patient demographics, stage of cancer at diagnosis, tumor characteristics (subtype and receptor status), type of surgery, systemic treatments received (hormonal, targeted therapy, and chemotherapy), RT variables, and recurrence and death dates. Data were analyzed to assess OS and DFS by using Kaplan-Meier analyses and the log-rank test. Univariate and multivariate Cox proportional hazard regression analyses were used to explore and identify factors associated with survival. Results  The median survival time in the study population was 9.16 years. Older age (65+ years) was associated with worse OS and DFS than was younger age (<65 years) (hazard ratio (HR) 3.20, 95% CI 1.48-6.90, P = 0.003 and HR 2.21, 95% CI 1.12-4.36, P = 0.022, respectively). Regarding the type of surgery, having a mastectomy was associated with worse OS and DFS than was having a lumpectomy (HR 2.44, 95% CI 0.97-6.12, P = 0.05 and HR 2.41, 95% CI 1.13-5.14, P = 0.023, respectively). Positive estrogen and progesterone receptor status was associated with better OS and DFS than was a negative estrogen or progesterone receptor status (HR 0.13, 95% CI 0.05-0.30, P < 0.001 and HR 0.21, 95% CI 0.11-0.41, P < 0.001, respectively). Patients who received RT had a lower risk of recurrence than did those who did not receive RT (P = 0.011). Moreover, three-dimensional conformal RT was associated with lower local recurrence than intensity-modulated RT or volumetric-modulated arc therapy (P = 0.003). Conclusion  Multiple factors can affect the OS and DFS in LABC. Younger patients, having hormone-positive disease, and undergoing lumpectomy were associated with better outcomes. Adjuvant RT may improve local control and the use of three-dimensional conformal RT was superior for local control. Prospective studies with larger sample sizes are needed to further highlight these findings and to assess the role of chemotherapy and targeted therapy in patients with LABC.

Atlas of sentinel lymph nodes in early breast cancer using single-photon emission computed tomography: implication for lymphatic contouring

PURPOSE

to determine the localization of sentinel lymph nodes (SLNs) in a large cohort of patients with breast cancer and validate the European Society for Therapeutic Radiology and Oncology (ESTRO), Radiation Therapy Oncology Group (RTOG), and Radiotherapy Comparative Effectiveness (RADCOMP) guidelines on regional lymph node clinical target volume (CTV-LN) delineation.

MATERIALS AND METHODS

A total of 254 women with cT1-3N0-1M0 breast cancer underwent single-photon emission computed tomography (SPECT-CT) visualization of SLNs after intra- and peritumoral injection of 99mTc-radiocolloids. All SPECT-CT images were fused with reference simulation computed tomography. A 3D atlas of SLNs was created and used for evaluation of CTV-LN defined by contouring guidelines.

RESULTS

SPECT-CT visualized 532 SLNs that were localized in axillary level I in 67.5%, level II in 15.4%, level III in 7.3%, internal mammary in 8.5%, and supraclavicular in 1.3% cases. The majority of level II-IV and internal mammary SLNs were inside the recommended CTV-LN. Axillary level I SLNs were covered by ESTRO and RTOG contours in 85% and 85% cases, respectively. "Out of contours" SLNs were mostly detected in lateral subgroup of level I LN (18.5%), while 98%-99% of anterior pectoral and central axillary SLNs were covered by CTV-LN. Internal mammary SLNs were visualized in 33 cases and were outside ESTRO and RTOG contours in 3 and 6 observations, respectively.

CONCLUSION

SPECT-CT atlas of SLNs demonstrated that in most cases ESTRO and RTOG guidelines correctly represented CTV-LNs with the exception of lateral subgroup of SLNs.

Suberosin Attenuates the Proliferation of MCF-7 Breast Cancer Cells in Combination with Radiotherapy or Hyperthermia

AIM

The aim of this study was to determine the proliferation of MCF-7 following irradiation or hyperthermia as alone or pre-treatment with suberosin.

BACKGROUND

Radiotherapy is a major therapeutic modality for the control of breast cancer. However, hyperthermia can be prescribed for relief of pain or enhancing cancer cell death. Some studies have attempted its use as an adjuvant to improve therapeutic efficiency. Suberosin is a cumarin- derived natural agent that has shown anti-inflammatory properties.

OBJECTIVE

In this in vitro study, possible sensitization effect of suberosin in combination with radiation or hyperthermia was evaluated.

METHODS

MCF-7 breast cancer cells were irradiated or received hyperthermia with or without treatment with suberosin. The incidence of apoptosis as well as viability of MCF-7 cells were observed. Furthermore, the expressions of pro-apoptotic genes such as Bax, Bcl-2, and some caspases were evaluated using real-time PCR.

RESULTS

Both radiotherapy or hyperthermia reduced the proliferation of MCF-7 cells. Suberosin amplified the effects of radiotherapy or hyperthermia for induction of pro-apoptotic genes and reducing cell viability.

CONCLUSION

Suberosin has a potent anti-cancer effect when combined with radiotherapy or hyperthermia. It could be a potential candidate for killing breast cancer cells as well as increasing the therapeutic efficiency of radiotherapy or hyperthermia.

A Systematic Review of Contouring Guidelines in Radiation Oncology: Analysis of Frequency, Methodology, and Delivery of Consensus Recommendations

PURPOSE

Clinical trials have described variation in radiation therapy plan quality, of which contour delineation is a key component, and linked this to inferior patient outcomes. In response, consensus guidelines have been developed to standardize contour delineation. This investigation assesses trends in contouring guidelines and examines the methodologies used to generate and deliver recommendations.

METHODS AND MATERIALS

We conducted a literature search for contouring guidelines published after 1995. Of 11,124 citations, 332 were identified for full-text review to determine inclusion. We abstracted articles for the intent of the consensus process, key elements of the methodology, and mode of information delivery. A Fisher exact test was used to identify elements that differed among the guidelines generated for clinical trials and routine care.

RESULTS

Overall, 142 guidelines were included, of which 16 (11%) were developed for a clinical trial. There was an increase in guideline publication over time (0 from 1995-1999 vs 65 from 2015- 2019; P = .03), particularly among recommendations for stereotactic radiation and brachytherapy. The most common disease sites were head and neck (24%), gastrointestinal (12%), and gynecologic (12%). Methods used to develop recommendations included literature review (50%) and image-based methods (45%). Panels included a median of 10 physicians (interquartile range, 7-16); 70% of panels represented multidisciplinary expertise. Guidelines developed for a clinical trial were more likely to include an image-based approach, with quantitative analysis of contours submitted by the panel members and to publish a full set of image-based recommendations (P < .005).

CONCLUSIONS

This review highlights an increase in consensus contouring recommendations over time. Guidelines focus on disease sites, such as head and neck, with evidence supporting a correlation between treatment planning and patient outcomes, although variation exists in the approach to the consensus process. Elements that may improve guideline acceptance (ie, image-based consensus contour analysis) and usability (ie, inclusion of a full image set) are more common in guidelines developed for clinical trials.

PET/CT of breast cancer regional nodal recurrences: an evaluation of contouring atlases

BACKGROUND

To validate the Radiation Therapy Oncology Group (RTOG) and European Society for Radiotherapy and Oncology (ESTRO) breast cancer nodal clinical target volumes (CTVs) and to investigate the Radiotherapy Comparative Effectiveness Consortium (RADCOMP) Posterior Neck volume in relation to regional nodal recurrences (RNR).

METHODS

From a population-based database, 69 patients were identified who developed RNR after curative treatment for breast cancer. RNRs were detected with 18-fluorodeoxyglucose-positron emission tomography-computed tomography (PET/CT). All patients were treatment-naïve for RNR when imaged. The RTOG and ESTRO nodal CTVs and RADCOMP Posterior Neck volumes were contoured onto a template patient's CT. RNRs were contoured on each PET/CT and deformed onto the template patient's CT. Each RNR was represented by a 5 mm diameter epicentre, and categorized as 'inside', 'marginal' or 'outside' the CTV boundaries.

RESULTS

Sixty-nine patients with 226 nodes (median 2, range 1-11) were eligible for inclusion. Thirty patients had received adjuvant tangent and regional nodal radiotherapy, 16 tangent-only radiotherapy and 23 no adjuvant radiotherapy. For the RTOG CTVs, the RNR epicentres were 70% (158/226) inside, 4% (8/226) marginal and 27% (60/226) outside. They included the full extent of the RNR epicentres in 38% (26/69) of patients. Addition of the RADCOMP Posterior Neck volume increased complete RNR coverage to 48% (33/69) of patients. For the ESTRO CTVs, the RNR epicentres were 73% (165/226) inside, 2% (4/226) marginal and 25% (57/226) outside. They included the full extent of the RNR epicentres in 57% (39/69) of patients. Addition of the RADCOMP Posterior Neck volume increased complete RNR coverage to 70% (48/69) of patients.

CONCLUSIONS

The RTOG and ESTRO breast cancer nodal CTVs do not fully cover all potential areas of RNR, but the ESTRO nodal CTVs provided full coverage of all RNR epicentres in 19% more patients than the RTOG nodal CTVs. With addition of the RADCOMP Posterior Neck volume to the ESTRO CTVs, 70% of patients had full coverage of all RNR epicentres.

Central Review of Radiation Therapy Planning Among Patients with Breast-Conserving Surgery: Results from a Quality Assurance Process Integrated into the INSEMA Trial

PURPOSE

After publication of the radiation field design in the American College of Surgeons Oncology Group Z0011 trial, a radiation therapy quality assurance review was integrated into the Intergroup-Sentinel-Mamma (INSEMA) trial. We aimed to investigate the role of patient characteristics, extent of axillary surgery, and radiation techniques for dose distribution in ipsilateral axillary levels.

METHODS AND MATERIALS

INSEMA (NCT02466737) has randomized 5542 patients who underwent breast-conserving surgery. Of these, 276 patients from 108 radiation therapy facilities were included in the central review, using the planning records of the first 3 patients treated at each site.

RESULTS

Of the 276 patients, 41 had major deviations (ie, no axillary contouring or submission of insufficient records) leading to exclusion. A total of 235 (85.1%) radiation therapy planning records were delineated according to the INSEMA protocol, including 9 (3.8%) cases with minor deviations. At least 25% of INSEMA patients were unintentionally treated with ≥95% of the prescribed breast radiation dose in axillary level I. Approximately 50% of patients were irradiated with a median radiation dose of more than 85% of prescription dose in level I. Irradiated volumes and applied doses were significantly lower in levels II and III compared with level I. However, 25% of patients still received a median radiation dose of ≥75% of prescription dose to level II. Subgroup analysis revealed a significant association between incidental radiation dose in the axilla and obesity. Younger age, boost application, and fractionation schedule showed no impact on axillary dose distribution.

CONCLUSIONS

Assuming ≥80% of prescribed breast dose as the optimal dose for curative radiation of low-volume disease in axillary lymph nodes, at least 50% of reviewed INSEMA patients received an adequate dose in level I, even with contemporary 3-dimensional techniques. Dose coverage was much less in axillary levels II and III, and far below therapeutically relevant doses.