The Cambridge Breast Intensity-modulated Radiotherapy Trial: patient- and treatment-related factors that influence late toxicity

Intensity-modulated radiation therapy for early-stage breast cancer: a systematic review and meta-analysis

BACKGROUND

Radiation therapy (RT) is a standard treatment for non-metastatic breast cancer and is associated with acute and late toxicities. Intensity-modulated RT (IMRT) may decrease toxicity and is convenient for patients.

OBJECTIVES

To assess the efficacy and safety of IMRT in women with early stage breast cancer.

DESIGN AND SETTING

Systematic review study; Multi-institutional centers.

METHODS

Seven databases were searched. Randomized controlled trials (RCT) comparing IMRT with any "non-IMRT" strategies were included. Primary outcomes were local control and acute toxicity. Cochrane Handbook was use to plan and conduct the review, and PRISMA 2020 was used to report results.

RESULTS

Five RCT involving 2,556 women (n = 1,283 IMRT; n = 1,274 control arm) were included. Baseline characteristics were similar between trials and arms. Local relapse-free survival rates were not different (hazard-ratio [HR] 0.62; 95%confidence interval [CI] -0.38 to 1.62; P > 0.05); however, IMRT reduced the overall acute toxicity (RR 0.69, 95%CI 0.58 to 0.82; P < 0.00001) and acute moist desquamation (risk-ratio [RR] 0.71, 95%CI 0.60 to 0.82; P < 0.00001). Lymphedema and pneumonitis rates, and survival outcomes were not affected by IMRT. The 2-year telangiectasia rate was decreased with IMRT (RR 0.66, 95%CI 0.47 to 0.93; P = 0.02); however, edema, pain, pigmentation, or fibrosis remained unaffected. IMRT did not improve cosmesis.

CONCLUSIONS

IMRT improved acute toxicity and lowered telangiectasia rates, without affecting oncological and aesthetic outcomes.

SYSTEMATIC REVIEW REGISTRATION

This review was registered at Cochrane Database of Systematic Reviews 2013, Issue 3. Art. No.: CD010420. https://doi.org/10.1002/14651858.CD010420.

Breast induration and irradiated volume in the DBCG HYPO trial: The impact of age, smoking, and boost

PURPOSE

To investigate the association between irradiated breast volume and grade 2-3 breast induration three years after radiotherapy in the phase III Danish Breast Cancer Group HYPO trial randomizing patients ≥ 41 years to whole breast irradiation (WBI) with 40 Gy/15fr versus 50 Gy/25fr.

METHODS

Treatment plans were available for all Danish patients. Associations between frequency of induration and irradiated volume, age, smoking status, and boost were assessed by logistic regression. A sequential boost was given to patients < 50 years or in case of a narrow (<2 mm) resection margin.

RESULTS

RT plans from 1,333 patients were analyzed with 178 (13 %) having grade 2-3 induration. 1135 patients had only WBI. For this group, induration was correlated with irradiated breast volume for patients ≥ 65 years (n = 343, 10 %/22 % for small/large irradiated volumes, p = 0.005) but not for patients aged 50-64 years (n = 792, 11 % for both small and large volumes, p = 0.82). Smoking doubled the frequency irrespective of irradiated volume and age. All patients < 50 years (n = 156) had a boost. A volume effect was found for this group (5 %/21 % induration for small/large volume, p = 0.002). 42 patients ≥ 50 years had a boost and 14 (33 %) had grade 2-3 induration, however, with a p-value > 0.05 due to the few numbers of patients.

CONCLUSION

A relationship between irradiated breast volume and 3-year frequency of breast induration was found for patients ≥ 65 years, whilst not for patients aged 50-64 years. Smoking doubled the risk of induration irrespective of volume and age. A dose-induration relationship was seen for boost patients < 50 years.

Topical use of chicory root extract gel on the incidence and severity of radiodermatitis in breast cancer patients: a randomized controled trial

BACKGROUND AND PURPOSE

Nearly 95% of women treated with radiotherapy for breast cancer experience some degree of radiodermatitis. Radiation therapy's most frequent side effect is skin damage. Managing radiation-induced skin reactions while maintaining treatment continuity is a challenging issue. The chicory plant has known anti-inflammatory properties. This study aimed to assess the effect of chicory root extract gel on the incidence and severity of radiodermatitis in breast cancer patients.

MATERIALS AND METHODS

This three-blind clinical trial was conducted in the radiation therapy department of Ayatollah Yasrebi Hospital in Kashan from September 2022 to February 2023. Forty-four breast cancer patients undergoing radiation therapy with a linear accelerator were randomly assigned to either the intervention group (n = 21) or the placebo group (n = 20). Participants applied topically chicory root extract gel or placebo twice daily, starting with their radiation therapy. The incidence and severity of dermatitis were assessed using the Radiation Therapy Oncology Group (RTOG) scale. Participants' characteristics were collected through a researcher-designed questionnaire. Data analysis was performed using chi-square tests, Fisher's exact test, independent t-tests, Mann-Whitney U tests, and generalized linear models with a Poisson distribution, using SPSS version 16 software.

RESULTS

No significant differences were found between the two groups regarding individual and clinical characteristics at the beginning of the study. The results indicated that the number of patients who did not develop dermatitis in later weeks was higher in the intervention group compared to the placebo group (P < 0.001). In the second and third weeks, grade 1 and 2 dermatitis incidence was higher in the placebo group than in the intervention group (P < 0.001). A comparison of the incidence of dermatitis between the two groups, in terms of the number of days to develop grade 1 dermatitis, showed that the average duration was longer in the intervention group than in the placebo group (P > 0.05). This comparison was insignificant for grade 3 dermatitis in either group. Additionally, when considering body mass index (BMI) as a confounding variable and adjusting for its effect, the results revealed that the intervention group developed grade 1 dermatitis significantly later than the placebo group (P < 0.001).

DISCUSSION AND CONCLUSION

Chicory root extract gel offers an effective, low-risk option for managing radiodermatitis in breast cancer patients. This aligns with the goals of supportive cancer care, which emphasize minimizing side effects, maintaining treatment efficacy, and improving the patient's quality of life.

TRIAL REGISTRATION

The study was registered in the Clinical Trials Center of Iran ( https://irct.behdasht.gov.ir ) with the number cod: IRCT20220601055055N1 on July 2, 2023.

The effectiveness of smoking cessation interventions after cancer diagnosis: A systematic review and meta-analysis

OBJECTIVES

patients with cancer who smoke have more side effects during and after treatment, and a lower survival rate than patients with cancer who quit smoking. Supporting patients with cancer to quit smoking should be standard care. The aim of this systematic review was to determine the most effective smoking cessation method for patients diagnosed with cancer.

METHODS

PubMed, Embase, Web of Science and Google Scholar were systematically searched. Included were randomized controlled trials and observational studies published after January 2000 with any smoking cessation intervention in patients with any type of cancer. Result of these studies were evaluated in a meta-analysis.

RESULTS

A total of 18,780 papers were retrieved. After duplicate removal and exclusion based on title and abstract, 72 publications were left. After full text screening, 19 (randomized) controlled trials and 20 observational studies were included. The overall methodological quality of the included studies, rated by GRADE criteria, was very low. Two out of 21 combined intervention trials showed a statistical significant effect. Meta-analysis of 18 RCTs and 3 observational studies showed a significant benefit of combined modality interventions (OR 1.67, 95% C.I.: 1.24-2.26, p = 0.0008) and behavioural interventions (OR 1.33, 95% C.I.: 1.02 - 1.74, p = 0.03), but not for single modality pharmacological interventions (OR 1.11; 95% C.I.: 0.69-1.78, p = 0.66).

CONCLUSION

A combination of pharmacological and behavioural interventions may be the most effective intervention for smoking cessation in patients with cancer.

A retrospective study on improving the accuracy of radiotherapy for patients with breast cancer with lymph node metastasis using Styrofoam

BACKGROUND

To retrospectively analyze the accuracy of radiotherapy using cone beam computed tomography (CBCT), Styrofoam fixation, and breast bracket fixation in the chest wall target area and supraclavicular lymphatic drainage area (supraclavicular target area) of patients with breast cancer.and compare the setting efficiency and comfort satisfaction.

PATIENTS AND METHODS

A total of 65 patients with postoperative lymphatic metastasis of breast cancer, including 36 cases of Styrofoam fixation and 29 cases of breast bracket fixation, were recruited from March 2021 to August 2022 and retrospectively analyzed. All the patients underwent CBCT scans weekly, and the setup errors of the chest wall and supraclavicular target volume were compared and recorded. The planning target volume (PTV) margins of the two groups were calculated using the correlation MPTV = 2.5Σ + 0.7σ. The setup time and comfort satisfaction scores of the two groups were recorded and analyzed. The correlations among errors in each direction were analyzed using the Pearson correlation analysis.

RESULTS

There was a significant difference in the left-right direction (X) axis of the chest wall target area between the Styrofoam and breast bracket groups (1.59 ± 1.47 mm vs. 2.05 ± 1.64 mm, P = 0.012). There were statistical differences in the ventrodorsal direction (Z) and bed angle of the supraclavicular target area, the data were (1.36 ± 1.27 mm vs. 1.75 ± 1.55 mm, P = 0.046; 0.47 ± 0.47° vs. 0.66 ± 0.59°, P = 0.006, respectively). In the X, Y, and Z directions, the respective PTV margins of the two groups in the chest wall target area were 5.01 mm, 5.99 mm, and 5.47 mm in the Styrofoam group, while those in the breast bracket group were 6.10 mm, 6.34 mm, and 6.10 mm, respectively. Moreover, the PTV margins of the supraclavicular target in the three directions were 3.69 mm, 3.86 mm, and 4.28 mm in the Styrofoam group, while those in the breast bracket group were 3.99 mm, 3.72 mm, and 5.45 mm, respectively. The setup time of the two groups was 3.4 ± 1.1 min and 5.5 ± 3.1 min (P = 0.007). The subjective comfort satisfaction scores of the two groups were 27.50 ± 1.24 and 25.44 ± 1.23 (P < 0.001).

CONCLUSIONS

The application of Styrofoam fixation in radiotherapy of breast cancer in the supraclavicular lymph node area has several advantages as compared to breast bracket fixation, including higher positioning accuracy, smaller external expansion boundary, improved work efficiency, and patients' comfort, which might provide a reference for clinical work.

Role of circ-FOXO3 and miR-23a in radiosensitivity of breast cancer

Identifying the radiosensitivity of cells before radiotherapy (RT) in breast cancer (BC) patients allows appropriate switching between routinely used treatment regimens and reduces adverse side effects in exposed patients. In this study, blood was collected from 60 women diagnosed with Invasive Ductal Carcinoma (IDC) BC and 20 healthy women. To predict cellular radiosensitivity, a standard G2-chromosomal assay was performed. From these 60 samples, 20 BC patients were found to be radiosensitive based on the G2 assay. Therefore, molecular studies were finally performed on two equal groups (20 samples each) of patients with and without cellular radiosensitivity. QPCR was performed to examine the expression levels of circ-FOXO3 and miR-23a in peripheral blood mononuclear cells (PBMCs) and RNA sensitivity and specificity were determined by plotting Receiver Operating Characteristic (ROC) curves. Binary logistic regression was performed to identify RNA involvement in BC and cellular radiosensitivity (CR) in BC patients. Meanwhile, qPCR was used to compare differential RNA expression in the radiosensitive MCF-7 and radioresistant MDA-MB-231 cell lines. An annexin -V FITC/PI binding assay was used to measure cell apoptosis 24 and 48 h after 2 Gy, 4 Gy, and 8 Gy gamma-irradiation. Results indicated that circ-FOXO3 was downregulated and miR-23a was upregulated in BC patients. RNA expression levels were directly associated with CR. Cell line results showed that circ-FOXO3 overexpression induced apoptosis in the MCF-7 cell line and miR-23a overexpression inhibited apoptosis in the MDA-MB-231 cell line. Evaluation of the ROC curves revealed that both RNAs had acceptable specificity and sensitivity in predicting CR in BC patients. Binary logistic regression showed that both RNAs were also successful in predicting breast cancer. Although only circ-FOXO3 has been shown to predict CR in BC patients, circ-FOXO3 may function as a tumor suppressor and miR-23a may function as oncomiR in BC. Circ-FOXO3 and miR-23a may be promising potential biomarkers for BC prediction. Furthermore, Circ-FOXO3 could be a potential biomarker for predicting CR in BC patients.

Epigenetic regulation of circ-HIPK3, circ-PVT1, miR-25, and miR-149 in radiosensitivity of breast cancer

Assessing the radiosensitivity of cells before administering radiation therapy (RT) to individuals diagnosed with breast cancer (BC) can facilitate the selection of appropriate treatment regimens and minimize the incidence of adverse side effects in patients undergoing radiation exposure. In this research, blood samples were obtained from 60 women who had been diagnosed with Invasive Ductal Carcinoma (IDC) Breast Cancer. The average age of the patients was 47 ± 9.93. Additionally, the study incorporated 20 healthy women, with an average age of 44.43 ± 6.7. A standard G2 assay was conducted to predict the cellular response to radiation. Out of the 60 samples, the G2 assay identified 20 patients with breast cancer who exhibited radiosensitivity. Hence, molecular investigations were ultimately conducted on two equivalent cohorts comprising 20 subjects each, one with and the other without cellular radiosensitivity. The expression levels of miR-149, miR-25, circ-PVT1, and circ-HIPK3 in peripheral blood mononuclear cells (PBMCs) were evaluated using quantitative polymerase chain reaction (qPCR). Receiver Operating Characteristic (ROC) curves were used to evaluate the sensitivity and specificity of the RNAs. An analysis using binary logistic regression was performed to investigate the relationship between RNAs and both BC and cellular radiosensitivity (CR) in patients with BC. The findings revealed a significant upregulation of Circ-HIPK3 and circ-PVT1 in individuals diagnosed with BC. The levels of Circ-HIPK3 and Circ-PVT1 were found to be directly associated with CR in BC patients. The analysis of the ROC curve demonstrated that circ-HIPK3 and circ-PVT1 exhibit favorable specificity and sensitivity in accurately predicting both BC and CR in patients with BC. The findings from the binary logistic regression analysis demonstrated that circ-HIPK3 and circ-PVT1 were effective predictors of both BC and CR. The ROC curve and binary logistic regression analyses provide evidence that miR-25 is a reliable predictor for BC patients exclusively. Our research has demonstrated that circ-HIPK3, circ-PVT1, and miR-25 may be involved in BC regulatory processes. The circular RNAs Circ-HIPK3 and circ-PVT1, as well as miR-25, among other significant biomarkers, could potentially serve as promising biomarkers for predicting BC. Furthermore, Circ-HIPK3 and circ-PVT1 have the potential to serve as biomarkers for predicting CR in BC patients.

Exploring women's experiences of breast or trunk lymphoedema following treatment for breast cancer

Background:The experiences of women who develop lymphoedema in the breast or trunk (BTL) after treatment for breast cancer have received little attention in either the academic or clinical setting. Consequently, women's support needs remain unrecognized.Objective and Design:As this study sought to gain an understanding of women's unheard experiences of a poorly understood condition, it was underpinned by The Silences Framework1 which facilitates research into sensitive or marginalized issues.Sample and Methods:Fourteen women with BTL participated in individual, unstructured interviews, some using photographs or drawings to reflect their experiences. The data was analyzed using the Listening Guide.2Findings:Participants revealed that they were unprepared for the development of BTL; for many, the symptoms were unfamiliar and distressing. Furthermore, their concerns were often dismissed by healthcare professionals (HCPs), leading to long delays in obtaining an accurate diagnosis and treatment. For some women, the practical and emotional impact of developing BTL was profound.Practice Implications:Increased awareness and education about the risk of BTL as a potential side-effect of treatment for breast cancer is required for HCPs and patients. This will alleviate distress, better prepare patients, and ensure timely referral for treatment to manage this chronic condition.

Dose-escalated simultaneous integrated boost radiotherapy in early breast cancer (IMPORT HIGH): a multicentre, phase 3, non-inferiority, open-label, randomised controlled trial

BACKGROUND

A tumour-bed boost delivered after whole-breast radiotherapy increases local cancer-control rates but requires more patient visits and can increase breast hardness. IMPORT HIGH tested simultaneous integrated boost against sequential boost with the aim of reducing treatment duration while maintaining excellent local control and similar or reduced toxicity.

METHODS

IMPORT HIGH is a phase 3, non-inferiority, open-label, randomised controlled trial that recruited women after breast-conserving surgery for pT1-3pN0-3aM0 invasive carcinoma from radiotherapy and referral centres in the UK. Patients were randomly allocated to receive one of three treatments in a 1:1:1 ratio, with computer-generated random permuted blocks used to stratify patients by centre. The control group received 40 Gy in 15 fractions to the whole breast and 16 Gy in 8 fractions sequential photon tumour-bed boost. Test group 1 received 36 Gy in 15 fractions to the whole breast, 40 Gy in 15 fractions to the partial breast, and 48 Gy in 15 fractions concomitant photon boost to the tumour-bed volume. Test group 2 received 36 Gy in 15 fractions to the whole breast, 40 Gy in 15 fractions to the partial breast, and 53 Gy in 15 fractions concomitant photon boost to the tumour-bed volume. The boost clinical target volume was the clip-defined tumour bed. Patients and clinicians were not masked to treatment allocation. The primary endpoint was ipsilateral breast tumour relapse (IBTR) analysed by intention to treat; assuming 5% 5-year incidence with the control group, non-inferiority was predefined as 3% or less absolute excess in the test groups (upper limit of two-sided 95% CI). Adverse events were assessed by clinicians, patients, and photographs. This trial is registered with the ISRCTN registry, ISRCTN47437448, and is closed to new participants.

FINDINGS

Between March 4, 2009, and Sept 16, 2015, 2617 patients were recruited. 871 individuals were assigned to the control group, 874 to test group 1, and 872 to test group 2. Median boost clinical target volume was 13 cm3 (IQR 7 to 22). At a median follow-up of 74 months there were 76 IBTR events (20 for the control group, 21 for test group 1, and 35 for test group 2). 5-year IBTR incidence was 1·9% (95% CI 1·2 to 3·1) for the control group, 2·0% (1·2 to 3·2) for test group 1, and 3·2% (2·2 to 4·7) for test group 2. The estimated absolute differences versus the control group were 0·1% (-0·8 to 1·7) for test group 1 and 1·4% (0·03 to 3·8) for test group 2. The upper confidence limit for test group 1 versus the control group indicated non-inferiority for 48 Gy. Cumulative 5-year incidence of clinician-reported moderate or marked breast induration was 11·5% for the control group, 10·6% for test group 1 (p=0·40 vs control group), and 15·5% for test group 2 (p=0·015 vs control group).

INTERPRETATION

In all groups 5-year IBTR incidence was lower than the 5% originally expected regardless of boost sequencing. Dose-escalation is not advantageous. 5-year moderate or marked adverse event rates were low using small boost volumes. Simultaneous integrated boost in IMPORT HIGH was safe and reduced patient visits.

FUNDING

Cancer Research UK.

Machine-learning prediction model for acute skin toxicity after breast radiation therapy using spectrophotometry

Purpose

Radiation-induced skin toxicity is a common and distressing side effect of breast radiation therapy (RT). We investigated the use of quantitative spectrophotometric markers as input parameters in supervised machine learning models to develop a predictive model for acute radiation toxicity.

Methods and materials

One hundred twenty-nine patients treated for adjuvant whole-breast radiotherapy were evaluated. Two spectrophotometer variables, i.e. the melanin (I_M) and erythema (I_E) indices, were used to quantitatively assess the skin physical changes. Measurements were performed at 4-time intervals: before RT, at the end of RT and 1 and 6 months after the end of RT. Together with clinical covariates, melanin and erythema indices were correlated with skin toxicity, evaluated using the Radiation Therapy Oncology Group (RTOG) guidelines. Binary group classes were labeled according to a RTOG cut-off score of ≥ 2. The patient's dataset was randomly split into a training and testing set used for model development/validation and testing (75%/25% split). A 5-times repeated holdout cross-validation was performed. Three supervised machine learning models, including support vector machine (SVM), classification and regression tree analysis (CART) and logistic regression (LR), were employed for modeling and skin toxicity prediction purposes.

Results

Thirty-four (26.4%) patients presented with adverse skin effects (RTOG ≥2) at the end of treatment. The two spectrophotometric variables at the beginning of RT (I_M,T0 and I_E,T0), together with the volumes of breast (PTV2) and boost surgical cavity (PTV1), the body mass index (BMI) and the dose fractionation scheme (FRAC) were found significantly associated with the RTOG score groups (p<0.05) in univariate analysis. The diagnostic performances measured by the area-under-curve (AUC) were 0.816, 0.734, 0.714, 0.691 and 0.664 for IM, IE, PTV2, PTV1 and BMI, respectively. Classification performances reported precision, recall and F1-values greater than 0.8 for all models. The SVM classifier using the RBF kernel had the best performance, with accuracy, precision, recall and F-score equal to 89.8%, 88.7%, 98.6% and 93.3%, respectively. CART analysis classified patients with I_M,T0 ≥ 99 to be associated with RTOG ≥ 2 toxicity; subsequently, PTV1 and PTV2 played a significant role in increasing the classification rate. The CART model provided a very high diagnostic performance of AUC=0.959.

Conclusions

Spectrophotometry is an objective and reliable tool able to assess radiation induced skin tissue injury. Using a machine learning approach, we were able to predict grade RTOG ≥2 skin toxicity in patients undergoing breast RT. This approach may prove useful for treatment management aiming to improve patient quality of life.

Cell Senescence-Related Pathways Are Enriched in Breast Cancer Patients With Late Toxicity After Radiotherapy and Low Radiation-Induced Lymphocyte Apoptosis

Background

Radiation-induced late effects are a common cause of morbidity among cancer survivors. The biomarker with the best evidence as a predictive test of late reactions is the radiation-induced lymphocyte apoptosis (RILA) assay. We aimed to investigate the molecular basis underlying the distinctive RILA levels by using gene expression analysis in patients with and without late effects and in whom we had also first identified differences in RILA levels.

Patients and Methods

Peripheral blood mononuclear cells of 10 patients with late severe skin complications and 10 patients without symptoms, selected from those receiving radiotherapy from 1993 to 2007, were mock-irradiated or irradiated with 8 Gy. The 48-h response was analyzed in parallel by RILA assay and gene expression profiling with Affymetrix microarrays. Irradiated and non-irradiated gene expression profiles were compared between both groups. Gene set enrichment analysis was performed to identify differentially expressed biological processes.

Results

Although differentially expressed mRNAs did not reach a significant adjusted p-value between patients suffering and not suffering clinical toxicity, the enriched pathways indicated significant differences between the two groups, either in irradiated or non-irradiated cells. In basal conditions, the main differentially expressed pathways between the toxicity and non-toxicity groups were the transport of small molecules, interferon signaling, and transcription. After 8 Gy, the differences lay in pathways highly related to cell senescence like cell cycle/NF-κB, G-protein-coupled receptors, and interferon signaling.

Conclusion

Patients at risk of developing late toxicity have a distinctive pathway signature driven by deregulation of immune and cell cycle pathways related to senescence, which in turn may underlie their low RILA phenotype.

Factors Associated with Late Local Radiation Toxicity after Post-Operative Breast Irradiation

Purpose. To assess determinants associated with late local radiation toxicity in patients treated for breast cancer. Methods. A systematic review was performed. All studies reporting ≥2 variables associated with late local radiation toxicity after treatment with postoperative whole breast irradiation were included. Cohort studies, randomized controlled trials, and cross-sectional studies were eligible designs. Study characteristics and definitions of determinants and outcome measures were extracted. If possible, the measure of association was extracted. Results. Twenty-one studies were included in this review. Six out of seven studies focused on the association between radiotherapy (boost) dose or irradiated breast volume and late radiation toxicity found significant results. Tumor bed boost was associated with late radiation toxicity, fibrosis, and/or edema in six out of twelve studies. Lower age was associated with late breast toxicity in one study, while in another study, higher age was significantly associated with breast fibrosis. Also, no association between age and late radiation toxicity was found in eight out of twelve studies. Similar inconsistent results were found in the association between late radiation toxicity and other patient-related factors (i.e., breast size, diabetes mellitus) and surgical and systemic treatment-related factors (i.e., complications after surgery, chemotherapy, and time between surgery and radiotherapy). Conclusion. In modern 3D radiotherapy, radiotherapy (boost) dose and volume are—like in 2D radiotherapy—associated with late local radiation toxicity, such as breast fibrosis and edema. Treatment de-escalation, for example, partial breast irradiation in selected patients might be important to decrease late local toxicity without compromising locoregional control and survival.

Development and optimisation of a machine-learning prediction model for acute desquamation following breast radiotherapy in the multi-centre REQUITE cohort

Purpose

Some patients with breast cancer treated by surgery and radiation therapy experience clinically significant toxicity, which may adversely affect cosmesis and quality of life. There is a paucity of validated clinical prediction models for radiation toxicity. We used machine learning (ML) algorithms to develop and optimise a clinical prediction model for acute breast desquamation after whole breast external beam radiation therapy in the prospective multicenter REQUITE cohort study.

Methods and Materials

Using demographic and treatment-related features (m = 122) from patients (n = 2058) at 26 centers, we trained 8 ML algorithms with 10-fold cross-validation in a 50:50 random-split data set with class stratification to predict acute breast desquamation. Based on performance in the validation data set, the logistic model tree, random forest, and naïve Bayes models were taken forward to cost-sensitive learning optimisation.

Results

One hundred and ninety-two patients experienced acute desquamation. Resampling and cost-sensitive learning optimisation facilitated an improvement in classification performance. Based on maximising sensitivity (true positives), the “hero” model was the cost-sensitive random forest algorithm with a false-negative: false-positive misclassification penalty of 90:1 containing m = 114 predictive features. Model sensitivity and specificity were 0.77 and 0.66, respectively, with an area under the curve of 0.77 in the validation cohort.

Conclusions

ML algorithms with resampling and cost-sensitive learning generated clinically valid prediction models for acute desquamation using patient demographic and treatment features. Further external validation and inclusion of genomic markers in ML prediction models are worthwhile, to identify patients at increased risk of toxicity who may benefit from supportive intervention or even a change in treatment plan.

Risk Factors Related to Acute Radiation Dermatitis in Breast Cancer Patients After Radiotherapy: A Systematic Review and Meta-Analysis

Background

Acute radiation dermatitis (ARD) is the most common acute response after adjuvant radiotherapy in breast cancer patients and negatively affects patients’ quality of life. Some studies have reported several risk factors that can predict breast cancer patients who are at a high risk of ARD. This study aimed to identify patient- and treatment-related risk factors associated with ARD.

Methods

PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, and WanFang literature databases were searched for studies exploring the risk factors in breast cancer patients. The pooled effect sizes, relative risks (RRs), and 95% CIs were calculated using the random-effects model. Potential heterogeneity and sensitivity analyses by study design, ARD evaluation scale, and regions were also performed.

Results

A total of 38 studies composed of 15,623 breast cancer patients were included in the analysis. Of the seven available patient-related risk factors, four factors were significantly associated with ARD: body mass index (BMI) ≥25 kg/m² (RR = 1.11, 95% CI = 1.06–1.16, I² = 57.1%), large breast volume (RR = 1.02, 95% CI = 1.01–1.03, I² = 93.2%), smoking habits (RR = 1.70, 95% CI = 1.24–2.34, I² = 50.7%), and diabetes (RR = 2.24, 95% CI = 1.53–3.27, I² = 0%). Of the seven treatment-related risk factors, we found that hypofractionated radiotherapy reduced the risk of ARD in patients with breast cancer compared with that in conventional fractionated radiotherapy (RR = 0.28, 95% CI = 0.19–0.43, I² = 84.5%). Sequential boost and bolus use was significantly associated with ARD (boost, RR = 1.91, 95% CI = 1.34–2.72, I² = 92.5%; bolus, RR = 1.94, 95% CI = 1.82–4.76, I² = 23.8%). However, chemotherapy regimen (RR = 1.17, 95% CI = 0.95–1.45, I² = 57.2%), hormone therapy (RR = 1.35, 95% CI = 0.94–1.93, I² = 77.1%), trastuzumab therapy (RR = 1.56, 95% CI = 0.18–1.76, I² = 91.9%), and nodal irradiation (RR = 1.57, 95% CI = 0.98–2.53, I² = 72.5%) were not correlated with ARD. Sensitivity analysis results showed that BMI was consistently associated with ARD, while smoking, breast volume, and boost administration were associated with ARD depending on study design, country of study, and toxicity evaluation scale used. Hypofractionation was consistently shown as protective. The differences between study design, toxicity evaluation scale, and regions might explain a little of the sources of heterogeneity.

Conclusion

The results of this systematic review and meta-analysis indicated that BMI ≥ 25 kg/m² was a significant predictor of ARD and that hypofractionation was consistently protective. Depending on country of study, study design, and toxicity scale used, breast volume, smoking habit, diabetes, and sequential boost and bolus use were also predictive of ARD.

Factors related to patient-reported cosmetic outcome after breast-conserving therapy for breast cancer

BACKGROUND

Multiple factors can affect cosmetic outcome after breast-conserving therapy. We investigated which combination of factors could optimally predict patient reported cosmetic outcome.

METHODS AND MATERIALS

Dutch patients treated with BCT between 2008 and 2013 were retrospectively analysed. Demographics, tumour characteristics, and treatment-related factors were obtained from available digital medical records. Patients were asked to indicate their degree of cosmetic satisfaction using the Harvard scale. Both univariable and multivariable logistic regression analyses were performed to create a prediction model.

RESULTS

The present study based on 220 patients shows that univariable analysis radiotherapy boost (OR 4.01 [1.85-8.70], p ≤ 0.001) and adjuvant chemotherapy (OR 2.67 [1.45-4.92], p = 0.002) were significantly associated with unsatisfactory cosmetic outcome. In multivariable analyses, only a radiotherapy boost remained significantly associated (OR 4.08 [1.76-9.49], p = 0.001) with poor cosmetic outcome, while adjuvant chemotherapy was no longer associated with it (OR 1.61 [0.81-3.24), p = 0.18). These two factors, together with tumour histology and lymph node staging, showed the highest predictive values, although the predictive property of the overall model was limited (AUC = 0.69).

CONCLUSION

In the present study, a variety of factors is explored. However, a radiotherapy boost was the only factor that was independently associated with a poor cosmetic outcome after BCT. This finding can be used for counselling in daily clinical practice. Creation of a prediction model will require further investigation.

Radiation-Induced Toxicity Risks in Photon Versus Proton Therapy for Synchronous Bilateral Breast Cancer

Purpose

This study compares photon and proton therapy plans for patients with synchronous bilateral early breast cancer and estimates risks of early and late radiation-induced toxicities.

Materials and Methods

Twenty-four patients with synchronous bilateral early breast cancer receiving adjuvant radiation therapy using photons, 3-dimensional conformal radiation therapy or volumetric modulated arc therapy, were included and competing pencil beam scanning proton therapy plans were created. Risks of dermatitis, pneumonitis, acute esophageal toxicity, lung and breast fibrosis, hypothyroidism, secondary lung and esophageal cancer and coronary artery events were estimated using published dose-response relationships and normal tissue complication probability (NTCP) models.

Results

The primary clinical target volume V95% and/or nodal clinical target volume V90% were less than 95% in 17 photon therapy plans and none of the proton plans. Median NTCP of radiation dermatitis ≥ grade 2 was 18.3% (range, 5.4-41.7) with photon therapy and 58.4% (range, 31.4-69.7) with proton therapy. Median excess absolute risk (EAR) of secondary lung cancer at age 80 for current and former smokers was 4.8% (range, 0.0-17.0) using photons and 2.7% (range, 0.0-13.6) using protons. Median EAR of coronary event at age 80, assuming all patients have preexisting cardiac risk factors, was 1.0% (range, 0.0-5.6) with photons and 0.2% (range, 0.0-1.3) with protons.

Conclusion

Proton therapy plans improved target coverage and reduced risk of coronary artery event and secondary lung cancer while increasing the risk of radiation dermatitis.

A Cross-Machine Comparison of Shear-Wave Speed Measurements Using 2D Shear-Wave Elastography in the Normal Female Breast

Quantitative measures of radiation-induced breast stiffness are required to support clinical studies of novel breast radiotherapy regimens and exploration of personalised therapy, however, variation between shear-wave elastography (SWE) machines may limit the usefulness of shear-wave speed (cs) for this purpose. Mean cs measured in four healthy volunteers’ breasts and a phantom using 2D-SWE machines Acuson S2000 (Siemens Medical Solutions) and Aixplorer (Supersonic Imagine) were compared. Shear-wave speed was measured in the skin region, subcutaneous adipose tissue and parenchyma. cs estimates were on average 2.3% greater when using the Aixplorer compared to S2000 in vitro. In vivo, cs estimates were on average 43.7%, 36.3% and 49.9% significantly greater (p << 0.01) when using the Aixplorer compared to S2000, for skin region, subcutaneous adipose tissue and parenchyma, respectively. In conclusion, despite relatively small differences between machines observed in vitro, large differences in absolute measures of shear wave speed measured were observed in vivo, which may prevent pooling of cross-machine data in clinical studies of the breast.

A data science approach for early-stage prediction of Patient's susceptibility to acute side effects of advanced radiotherapy

The prediction by classification of side effects incidence in a given medical treatment is a common challenge in medical research. Machine Learning (ML) methods are widely used in the areas of risk prediction and classification. The primary objective of such algorithms is to use several features to predict dichotomous responses (e.g., disease positive/negative). Similar to statistical inference modelling, ML modelling is subject to the class imbalance problem and is affected by the majority class, increasing the false-negative rate. In this study, seventy-nine ML models were built and evaluated to classify approximately 2000 participants from 26 hospitals in eight different countries into two groups of radiotherapy (RT) side effects incidence based on recorded observations from the international study of RT related toxicity "REQUITE". We also examined the effect of sampling techniques and cost-sensitive learning methods on the models when dealing with class imbalance. The combinations of such techniques used had a significant impact on the classification. They resulted in an improvement in incidence status prediction by shifting classifiers' attention to the minority group. The best classification model for RT acute toxicity prediction was identified based on domain experts' success criteria. The Area Under Receiver Operator Characteristic curve of the models tested with an isolated dataset ranged from 0.50 to 0.77. The scale of improved results is promising and will guide further development of models to predict RT acute toxicities. One model was optimised and found to be beneficial to identify patients who are at risk of developing acute RT early-stage toxicities as a result of undergoing breast RT ensuring relevant treatment interventions can be appropriately targeted. The design of the approach presented in this paper resulted in producing a preclinical-valid prediction model. The study was developed by a multi-disciplinary collaboration of data scientists, medical physicists, oncologists and surgeons in the UK Radiotherapy Machine Learning Network.

Breast edema, from diagnosis to treatment: state of the art

Introduction

Breast edema can arise from different etiologies; however, it is mostly seen after breast conserving surgery and/or radiotherapy. Combining breast conserving surgery and radiotherapy can cause damage to the lymphatic system and reactions to surrounding tissues, which can lead to breast edema; hereby, the breast size can increase by more than one cup size. Swelling of the breast is not the only criterion associated with breast edema. Other common criteria found in literature are peau d’orange, heaviness of the breast, skin thickening, breast pain, redness of the skin, hyperpigmented skin pores and a positive pitting sign. Despite the benefits of breast conserving surgery, breast edema can be uncomfortable, and can negatively influence quality of life in suffering patients. In contrast to lymphedema of the arm, which is well known in clinical practice and in research, breast edema is often underestimated and far less explored in literature. Currently, many aspects still need to be reviewed.

Purpose and importance to practice

This masterclass aims at providing the state of the art of breast edema for all health care workers and researchers involved in the treatment and monitoring of breast cancer patients. It includes current and future perspectives on its diagnosis, longitudinal course and treatment. Furthermore, recommendations for clinical practice and future research are discussed.

Clinical implications

It is recommended to closely monitor those patients in whom breast edema symptoms do not decline within 6 months after termination of radiotherapy and provide them with the appropriate therapy. Since evidence concerning the treatment of breast edema is currently lacking, we recommend the complex decongestive therapy (CDT) to the utmost extent, by analogy with the lymphedema treatment of the extremities. This treatment involves skin care, exercise therapy and compression. Additionally, all patients should be informed about the normal course of breast edema development.

Future research priorities

A consensus should be reached among clinicians and researchers concerning the definition, assessment methods and best treatment of breast edema. Furthermore, high quality studies are necessary to prove the effectiveness of the CDT for breast edema.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40945-021-00103-4.

External Validation of a Predictive Model for Acute Skin Radiation Toxicity in the REQUITE Breast Cohort

Background: Acute skin toxicity is a common and usually transient side-effect of breast radiotherapy although, if sufficiently severe, it can affect breast cosmesis, aftercare costs and the patient's quality-of-life. The aim of this study was to develop predictive models for acute skin toxicity using published risk factors and externally validate the models in patients recruited into the prospective multi-center REQUITE (validating pREdictive models and biomarkers of radiotherapy toxicity to reduce side-effects and improve QUalITy of lifE in cancer survivors) study.

Methods: Patient and treatment-related risk factors significantly associated with acute breast radiation toxicity on multivariate analysis were identified in the literature. These predictors were used to develop risk models for acute erythema and acute desquamation (skin loss) in three Radiogenomics Consortium cohorts of patients treated by breast-conserving surgery and whole breast external beam radiotherapy (n = 2,031). The models were externally validated in the REQUITE breast cancer cohort (n = 2,057).

Results: The final risk model for acute erythema included BMI, breast size, hypo-fractionation, boost, tamoxifen use and smoking status. This model was validated in REQUITE with moderate discrimination (AUC 0.65), calibration and agreement between predicted and observed toxicity (Brier score 0.17). The risk model for acute desquamation, excluding the predictor tamoxifen use, failed to validate in the REQUITE cohort.

Conclusions: While most published prediction research in the field has focused on model development, this study reports successful external validation of a predictive model using clinical risk factors for acute erythema following radiotherapy after breast-conserving surgery. This model retained discriminatory power but will benefit from further re-calibration. A similar model to predict acute desquamation failed to validate in the REQUITE cohort. Future improvements and more accurate predictions are expected through the addition of genetic markers and application of other modeling and machine learning techniques.

The impact of smoking on adjuvant breast cancer radiation treatment: A systematic review

BACKGROUND

The influence of cigarette smoking on cancer risk has been well-studied. Similarly, exposure to ionizing radiation from radiotherapy (RT) can produce detrimental effects on an individual's health. In patients administered RT, there has been an observed relationship in other primary carcinomas. The purpose of this systematic review was to summarize the influence of cigarette smoking on outcomes post adjuvant RT in breast cancer patients.

METHODS

OVID Medline, Cochrane and Embase were searched and 1893 articles were identified. A total of 71 articles were included in the review. Study type, published year and sample size, age, systemic therapies, RT techniques and treatment side effects were collected if available.

RESULTS

The review found 198 different outcomes which fell into 7 categories and similar outcomes were recorded. 40% of skin reaction outcomes, 50% of cardiovascular outcomes, 71% of reconstruction outcomes, 29% of pulmonary function outcomes, 33% of mortality outcomes and 42% of secondary recurrence outcomes reported significant differences between smokers and non-smokers. None of the articles reported non-smokers to have a higher risk than smokers.

CONCLUSION

Cigarette smoking can pose a higher risk of post-treatment complications that can influence an individual's quality of life, survival rate and/or recurrence risk. This review further assessed the impact of smoking on various patient outcomes and side-effects in the adjuvant breast RT setting. The information provided in this review suggest that smoking cessation programs would help educate patients to understand their risks of being a current or former smoker when undergoing RT.

Successful Relief of a Male Breast Lymphedema by Supermicrosurgical Lymphaticovenular Anastomosis

BACKGROUND

Breast lymphedema is a common issue after breast cancer surgery but remains understudied because it is difficult to be quantified. Untreated breast lymphedema may lead to severe form of delayed breast cellulitis. Supermicrosurgical lymphaticovenular anastomosis is one option for the treatment of breast cancer-related lymphedema but has not been described for the treatment of breast lymphedema.

METHODS

This report presented a rare case of male breast lymphedema secondary to axillary lymph node dissection for the treatment of a forearm melanoma. Deep lymphatic vessels and adjacent venules were individualized under high magnification in the periareolar area. Six lymphaticovenular anastomoses were performed using supermicrosurgical techniques. A clinical examination and a volume assessment under magnetic resonance imaging were used to assess the efficiency of surgery.

RESULTS

Postoperative outcome was uneventful. The patient was followed-up during 1 year. Swelling relief was clinically significant 3 months postoperatively. The pinch test reduction was 2 cm after 12 months. The breast volume reduction rate was 47.2%.

CONCLUSIONS

Supermicrosurgical lymphaticovenular anastomosis may be efficient for the treatment of postoperative breast lymphedema, even in male patients.

A literature review of the role of brachytherapy in the management of early-stage breast cancer

Background:

This review evaluates whether brachytherapy can be considered as an alternative to whole breast irradiation (WBI) using criteria such as local recurrence rates, overall survival rates and quality of life (QoL) factors. This is an important issue because of a decline in local recurrence rates, suggesting that some women at very low risk of recurrence may be incurring the negative long-term side effects of WBI without benefitting from a reduction in local recurrence and greater overall survival. As such, the purpose of this literature review is to evaluate whether brachytherapy is a credible alternative to external beam radiation with a particular focus on the impact it has on patient QoL.

Methods:

The search terms used were devised by using the Population Intervention Comparison Outcome framework, and a literature search was carried out using Boolean connectors and Medical Subject Headings in the PubMed database. The resultant articles were manually assessed for relevance and appraised using the Scottish Intercollegiate Guidelines Network tool. Additional papers were sourced from the citations of articles found using the search strategy. Government guidelines and regulations were also used following a manual search on the National Institute for Health and Care Excellence website. This process resulted in a total of 30 sources being included as part of the review.

Results:

Three types of brachytherapy were the foundation for the majority of the papers found: interstitial multi-catheter brachytherapy, intra-cavity brachytherapy and permanent seed implantation. The key themes that arose from the literature were that brachytherapy is equivalent to WBI both in terms of 5-year local recurrence rates and overall survival rates at 10–12 years. The findings showed that brachytherapy was superior to WBI for some QoL factors such as being less time-consuming and equal in terms of others such as breast cosmesis. The results did also show that brachytherapy does come with its own local toxicities that could impact upon QoL such as the poor breast cosmesis associated with some brachytherapy techniques.

Conclusion:

In conclusion, brachytherapy was deemed a safe or acceptable alternative to WBI, but there is a need for further research on the long-term local recurrence rates, survival rates and quality of life issues as the volume of evidence is still significantly smaller for brachytherapy than for WBI. Specifically, there needs to be further investigation as to which patients will benefit from being offered brachytherapy and the influence that factors such as co-morbidities, performance status and patient choice play in these decisions.

Multi-centre technical evaluation of the radiation-induced lymphocyte apoptosis assay as a predictive test for radiotherapy toxicity

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The RILA assay is the leading candidate biomarker for radiotherapy toxicity.

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We describe work to standardise its use across multiple centres.

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Patient factors including smoking and arthritis were found to affect RILA score.

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RILA predicts acute breast pain but not other acute end-points.

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This work establishes the basis for implementing the assay clinically.

Predicting which patients will develop adverse reactions to radiotherapy is important for personalised treatment. Prediction will require an algorithm or nomogram combining clinical and biological data. The radiation-induced lymphocyte apoptosis (RILA) assay is the leading candidate as a biological predictor of radiotherapy toxicity. In this study we tested the potential of the assay for standardisation and use in multiple testing laboratories.

The assay was standardised and reproducibility determined using samples from healthy volunteers assayed concurrently in three laboratories in Leicester (UK), Mannheim (Germany) and Montpellier (France). RILA assays were performed on samples taken prior to radiotherapy from 1319 cancer patients enrolled in the REQUITE project at multiple centres. The patients were being treated for breast (n = 753), prostate (n = 506) or lung (n = 60) cancer.

Inter-laboratory comparisons identified several factors affecting results: storage time, incubation periods and type of foetal calf serum. Following standardisation, there was no significant difference in results between the centres. Significant differences were seen in RILA scores between cancer types (prostate > breast > lung), by smoking status (non-smokers > smokers) and co-morbidity with rheumatoid arthritis (arthritics > non-arthritics).

An analysis of acute radiotherapy toxicity showed as expected that RILA assay does not predict most end-points, but unexpectedly did predict acute breast pain. This result may elucidate the mechanism by which the RILA assay predicts late radiotherapy toxicity.

The work shows clinical trials involving multiple laboratory measurement of the RILA assay are feasible and the need to account for tumour type and other variables when applying to predictive models.

Predictive factors for persistent and late radiation complications in breast cancer survivors

PURPOSE

With improved diagnostic techniques and treatments of breast cancer, overall survival times are longer, giving more opportunity for normal tissue complications of treatment to manifest. Radiation late effects (RLEs) could have profound long-term impacts on the quality of life of the survivors. The aim of this study was to identify predictive factors influencing timing and types of complications in patients referred to the Adult Radiation Late Effects Clinic (ARLEC).

METHODS

In a period of 16 years, 296 breast cancer patients were referred to the ARLEC. The clinical records were retrospectively studied to collect epidemiologic, medical and treatment data. Associations were sought between candidate predictive factors and time to the first complication after radiation treatment (RT) completion (primary outcome), and pain or swelling (secondary outcomes) using univariable and multivariable linear and logistic regression analyses. All analyses were performed in SAS, version 9.4.

RESULTS

All patients were female with a mean age of 56.3 years. The first treatment-related complication occurred after a median of 3 months. Patients were followed at ARLEC for a median of 18 months. Older age and delay from surgery to RT (S-RT delay) were associated with earlier onset of complications (both p < 0.001). The most common complications were breast pain (62.1%) and swelling (45.9%). Histology and RT boost were associated with pain (p = 0.035 and 0.013). RT boost and S-RT delay on the other hand were associated with swelling (p = 0.013 and 0.005).

CONCLUSIONS

Clinical factors identified could help recognize the patients at high risk for developing RLEs and alert physicians to initiate earlier diagnostic and therapeutic measures.

Breast Edema Following Breast-Conserving Surgery and Radiotherapy: Patient-Reported Prevalence, Determinants, and Effect on Health-Related Quality of Life

Background

The association between lymphedema of the arm and impaired health-related QoL (HR-QoL) has led to changes in clinical practice. However, data on lymphedema of the breast (ie, breast edema) are lacking. We prospectively evaluated patient-reported prevalence and determinants of breast edema and its effect on patient-reported HR-QoL and breast pain.

Methods

We prospectively included 836 patients undergoing breast-conserving surgery followed by radiotherapy between October 2013 and October 2016 (UMBRELLA cohort). Patient-reported breast edema, HR-QoL, and breast pain were assessed by means of European Organisation for Research and Treatment of Cancer-C30/BR23 before starting radiotherapy and at 3, 6, 12, and 18 months thereafter. We assessed which patient, tumor, and treatment characteristics were associated with breast edema. With mixed-effects models, we assessed the impact of breast edema on patient-reported HR-QoL domains and breast pain over time, adjusting for confounders.

Results

Within a median follow-up of 28 months (interquartile range [IQR] = 15), 207 (24.8%) patients reported breast edema at some point in time. Prevalence of breast edema was highest at 6 months (12.4%, 95% confidence interval [CI] = 10.0 to 14.7). Larger tumor size, oncoplastic surgery, axillary lymph node dissection, locoregional radiotherapy, radiotherapy boost on the tumor bed, and adjuvant chemotherapy were associated with breast edema. Breast edema was independently associated with more breast pain and with poorer QoL, physical functioning, and body image.

Conclusions

Breast edema occurs frequently within the first year after breast-conserving surgery and radiotherapy and is independently associated with impaired HR-QoL and more breast pain. This information is important for use in clinical practice and should be discussed with patients during shared decision making.

Topical atorvastatin 1% for prevention of skin toxicity in patients receiving radiation therapy for breast cancer: a randomized, double-blind, placebo-controlled trial

BACKGROUND AND PURPOSE

The purpose of this randomized, placebo-controlled, double-blind study was to investigate the preventive effect of topical administration of atorvastatin (ATV) on the acute radiation-induced skin toxicity in patients with breast cancer.

PATIENTS AND METHODS

Seventy breast cancer patients were randomly assigned to use topical ATV 1% or placebo gels during radiotherapy twice daily. Radiation-induced dermatitis was classified according to the radiation therapy oncology group (RTOG) criteria, as well as pain and itching were scored according to VAS (visual analogue scale) for 6 weeks of treatment.

RESULTS

Topical administration of ATV gel during radiotherapy reduced significantly radiation-induced breast swelling, itching, and pain in breast cancer patients by factors of 1.8, 1.7, and 1.5, respectively. ATV reduced the redness caused by radiotherapy in patients as compared with placebo; however, this difference was statistically not significant.

CONCLUSION

ATV was able to reduce significantly itching, breast edema, and pain in patients during radiotherapy.

Rate of individuals with clearly increased radiosensitivity rise with age both in healthy individuals and in cancer patients

BACKGROUND

The question of an age dependence of individual radiosensitivity has only marginally been studied so far. Therefore, we analyzed blood samples of healthy individuals and cancer patients of different ages to determine individual radiosensitivity.

METHODS

Ex vivo irradiated blood samples of 595 individuals were tested. Chromosomes 1, 2 and 4 were stained by 3-color fluorescence in situ hybridization and aberrations were analyzed. Radiosensitivity was determined by the mean breaks per metaphase (B/M).

RESULTS

Healthy individuals (mean age 50.7 years) had an average B/M value of 0.42 ± 0.104 and an increase of 0.0014B/M per year. The patients (mean age 60.4 years) had an average B/M value of 0.44 ± 0.150 and radiosensitivity did not change with age. In previous studies we found that from a value of 0.6B/M on an individual is considered to be distinctly radiosensitive. The portion of radiosensitive individuals (B/M > 0.6) increased in both cohorts with age.

CONCLUSION

Individual radiosensitivity rises continuously with age, yet with strong interindividual variation. No age related increase of radiosensitivity can be demonstrated in patients due to the strong interindividual variation. However among old cancer patients there is a higher probability to have patients with clearly increased radiosensitivity than at younger age.

A new approach for modeling patient overall radiosensitivity and predicting multiple toxicity endpoints for breast cancer patients

INTRODUCTION

Evaluation of patient characteristics inducing toxicity in breast radiotherapy, using simultaneous modeling of multiple endpoints.

METHODS AND MATERIALS

In 269 early-stage breast cancer patients treated with whole-breast irradiation (WBI) after breast-conserving surgery, toxicity was scored, based on five dichotomized endpoints. Five logistic regression models were fitted, one for each endpoint and the effect sizes of all variables were estimated using maximum likelihood (MLE). The MLEs are improved with James-Stein estimates (JSEs). The method combines all the MLEs, obtained for the same variable but from different endpoints. Misclassification errors were computed using MLE- and JSE-based prediction models. For associations, p-values from the sum of squares of MLEs were compared with p-values from the Standardized Total Average Toxicity (STAT) Score.

RESULTS

With JSEs, 19 highest ranked variables were predictive of the five different endpoints. Important variables increasing radiation-induced toxicity were chemotherapy, age, SATB2 rs2881208 SNP and nodal irradiation. Treatment position (prone position) was most protective and ranked eighth. Overall, the misclassification errors were 45% and 34% for the MLE- and JSE-based models, respectively. p-Values from the sum of squares of MLEs and p-values from STAT score led to very similar conclusions, except for the variables nodal irradiation and treatment position, for which STAT p-values suggested an association with radiosensitivity, whereas p-values from the sum of squares indicated no association. Breast volume was ranked as the most significant variable in both strategies.

DISCUSSION

The James-Stein estimator was used for selecting variables that are predictive for multiple toxicity endpoints. With this estimator, 19 variables were predictive for all toxicities of which four were significantly associated with overall radiosensitivity. JSEs led to almost 25% reduction in the misclassification error rate compared to conventional MLEs. Finally, patient characteristics that are associated with radiosensitivity were identified without explicitly quantifying radiosensitivity.

The Patient Perspective on Radiogenomics Testing for Breast Radiation Toxicity

AIMS

In the field of radiogenomics, several potential predictive genetic markers have been identified that are associated with individual susceptibility to radiation toxicity. Predictive models of radiation toxicity incorporating radiogenomics and other biomarkers are being developed as part of the ongoing multicentre REQUITE trial. The purpose of this study was to explore patient attitudes towards future predictive radiogenomics testing for breast radiation toxicity.

PATIENTS AND METHODS

Twenty-one semi-structured interviews were conducted with breast cancer patients taking part in the REQUITE study at one centre. We used inductive thematic analysis to generate common themes.

RESULTS

We identified three emerging themes describing attitudes and feelings towards a predictive radiogenomics test for breast radiation toxicity: theme 1 - willingness to undergo a test (subthemes - information, trusted expert); theme 2 - implications of a test (subthemes - preparation and planning, anxiety without recourse); theme 3 - impact on treatment decision-making (subthemes - prioritising cancer cure, preserving breast integrity, patient preferences).

CONCLUSIONS

Results from the present study indicate that patients support and have confidence in the validity of a radiogenomics test for breast radiation toxicity, but they would prefer the result be provided to healthcare professionals. Except in cases of significant chronic symptoms and pain or significant end-organ damage, participants in this study rarely felt that advance knowledge of their personal risk of breast radiation toxicity would influence their treatment decision-making. These findings provide a number of insights that will allow us to anticipate how patients are likely to engage with predictive radiogenomics testing in the future.

Advancements and Personalization of Breast Cancer Treatment Strategies in Radiation Therapy

Significant technologic advances in radiation treatment delivery now allow for more personalized delivery considerations which incorporate individual patient characteristics (such as tumor location and patient anatomy) and more precise delivery in the breast conservation or post-mastectomy setting. The combined advancements with other treatment modalities (i.e., systemic therapy, surgical management) have had direct effects on local-regional management and outcomes such that currently, local-regional relapses after definitive treatment for localized disease are now rarely experienced. Recent advances in the radiation therapy field have come from careful patient selection for a variety of three-dimensional treatment delivery techniques and alternatives to conventional tangential radiation. These advances have been demonstrated to diminished acute/long-term toxicity, minimized dose to surrounding normal tissue structures such as the heart and lung, and ultimately result in an improvement in the therapeutic ratio for radiation treatment. This chapter discusses recent radiation innovations and appropriate patient selection for their application, for a more personalized approach to radiation therapy for breast cancer patients.

Novel Radiotherapy Techniques for Breast Cancer

During the early decades of radiation therapy for breast cancer, local control of disease was documented consistently but, enigmatically, an anticipated impact on breast cancer survival was not observed, leading to confusion in our understanding of the natural history of breast cancer and radiation effects. Now, almost 90 years after its first use in breast cancer, technology developments in diagnostic imaging and radiation therapy have elucidated parts of this enigma. The data now available demonstrate a significant impact of radiation therapy on survival as well as disease control and treatment-related mortality, opening a doorway to understanding the powerful impact of radiation therapy on both breast cancer and critical organs. Efforts are focused on leveraging novel techniques to maximize the benefits of radiation for breast cancer patients.

Side Effects Associated with the Use of Intensity-Modulated Radiation Therapy in Breast Cancer Patients Undergoing Adjuvant Radiation Therapy: A Systematic Review and Meta-Analysis

PURPOSE

The purpose of the study was to establish the efficacy and safety of breast intensity-modulated radiation therapy (IMRT) compared with non-IMRT standard wedge radiation therapy (RT) for the treatment of adjuvant breast cancer.

METHODS

A systematic review and meta-analysis were completed using STATA and a random effects model. A total of 1,499 citations were identified from the literature search. Of those, 1,475 were excluded based on abstract review. Full texts of 24 remaining articles were reviewed and 11 articles were included in the final analysis. Side effects were analysed as the primary outcomes of interest. We calculated individual odds ratios and 95% confidence intervals for 17 classifications of side effects reported. The data for eight classifications of side effects were then pooled for meta-analyses to obtain more precise estimates of the relationships between adjuvant RT and a particular side effect.

RESULTS

The pooled analyses revealed potential protective associations between adjuvant IMRT and two acute side effects: dermatitis and moist desquamation. The remaining pooled estimates suggest that the odds of developing edema, hyperpigmentation, fat necrosis, pain, induration were no worse, nor better among those treated with IMRT compared with those treated with non-IMRT standard wedge RT.

CONCLUSION

The pooled estimates from this meta-analysis are in line with the existing evidence. When the outcome of interest is reduction of the acute side effects: dermatitis and moist desquamation IMRT is a viable treatment option for women undergoing external beam RT after breast-conserving surgery.

Intensity modulated radiation therapy for breast cancer: current perspectives

Background

Owing to highly conformed dose distribution, intensity modulated radiation therapy (IMRT) has the potential to improve treatment results of radiotherapy (RT). Postoperative RT is a standard adjuvant treatment in conservative treatment of breast cancer (BC). The aim of this review is to analyze available evidence from randomized controlled trials (RCTs) on IMRT in BC, particularly in terms of reduction of side effects.

Methods

A literature search of the bibliographic database PubMed, from January 1990 through November 2016, was performed. Only RCTs published in English were included.

Results

Ten articles reporting data from 5 RCTs fulfilled the selection criteria and were included in our review. Three out of 5 studies enrolled only selected patients in terms of increased risk of toxicity. Three studies compared IMRT with standard tangential RT. One study compared the results of IMRT in the supine versus the prone position, and one study compared standard treatment with accelerated partial breast IMRT. Three studies reported reduced acute and/or late toxicity using IMRT compared with standard RT. No study reported improved quality of life.

Conclusion

IMRT seems able to reduce toxicity in selected patients treated with postoperative RT for BC. Further analyses are needed to better define patients who are candidates for this treatment modality.

Initial Results from the Royal College of Radiologists' UK National Audit of Anal Cancer Radiotherapy 2015

AIMS

UK guidance was recently developed for the treatment of anal cancer using intensity-modulated radiotherapy (IMRT). We audited the current use of radiotherapy in UK cancer centres for the treatment of anal cancer against such guidance. We describe the acute toxicity of IMRT in comparison with patient population in the audit treated with two-phase conformal radiotherapy and the previous published data from two-phase conformal radiotherapy, in the UK ACT2 trial.

MATERIALS AND METHODS

A Royal College of Radiologists' prospective national audit of patients treated with radiotherapy in UK cancer centres was carried out over a 6 month period between February and July 2015.

RESULTS

Two hundred and forty-two cases were received from 40/56 cancer centres (71%). In total, 231 (95%) underwent full dose radiotherapy with prophylactic nodal irradiation. Of these, 180 (78%) received IMRT or equivalent, 52 (22%) two-phase conformal (ACT2) technique. The number of interruptions in radiotherapy treatment in the ACT2 trial was 15%. Interruptions were noted in 7% (95% confidence interval 0-14%) of courses receiving two-phase conformal and 4% (95% confidence interval 1-7%) of those receiving IMRT. The percentage of patients completing the planned radiotherapy dose, irrelevant of gaps, was 90% (95% confidence interval 82-98%) and 96% (95% confidence interval 93-99%), in two-phase conformal and IMRT respectively. The toxicity reported in the ACT2 trial, in patients receiving two-phase conformal in the audit and in patients receiving IMRT in the audit was: any toxic effect 71%, 54%, 48%, non-haematological 62%, 49%, 40% and haematological 26%, 13%, 18%, respectively.

CONCLUSIONS

IMRT implementation for anal cancer is well underway in the UK with most patients receiving IMRT delivery, although its usage is not yet universal. This audit confirms that IMRT results in reduced acute toxicity and minimised treatment interruptions in comparison with previous two-phase conformal techniques.

In vitro cellular radiosensitivity in relationship to late normal tissue reactions in breast cancer patients: a multi-endpoint case-control study

PURPOSE

A minority of patients exhibits severe late normal tissue toxicity after radiotherapy (RT), possibly related to their inherent individual radiation sensitivity. This study aimed to evaluate four different candidate in vitro cellular radiosensitivity assays for prediction of late normal tissue reactions, in a retrospective matched case-control set-up of breast cancer patients.

METHODS

The study population consists of breast cancer patients expressing severe radiation toxicity (12 cases) and no or minimal reactions (12 controls), with a follow-up for at least 3 years. Late adverse reactions were evaluated by comparing standardized photographs pre- and post-RT resulting in an overall cosmetic score and by clinical examination using the LENT-SOMA scale. Four cellular assays on peripheral blood lymphocytes reported to be associated with normal tissue reactions were performed after in vitro irradiation of patient blood samples to compare case and control radiation responses: radiation-induced CD8+ late apoptosis, residual DNA double-strand breaks, G0 and G2 micronucleus assay.

RESULTS

A significant difference was observed for all cellular endpoints when matched cases and controls were compared both pairwise and grouped. However, it is important to point out that most case-control pairs showed a substantial overlap in standard deviations, which questions the predictive value of the individual assays. The apoptosis assay performed best, with less apoptosis seen in CD8+ lymphocytes of the cases (average: 14.45%) than in their matched controls (average: 30.64%) for 11 out of 12 patient pairs (p < .01). The number of residual DNA DSB was higher in cases (average: 9.92 foci/cell) compared to their matched control patients (average: 9.17 foci/cell) (p < .01). The average dose response curve of the G0 MN assay for cases lies above the average dose response curve of the controls. Finally, a pairwise comparison of the G2 MN results showed a higher MN yield for cases (average: 351 MN/1000BN) compared to controls (average: 219 MN/1000BN) in 9 out of 10 pairs (p < .01).

CONCLUSION

This matched case-control study in breast cancer patients, using different endpoints for in vitro cellular radiosensitivity related to DNA repair and apoptosis, suggests that patients' intrinsic radiosensitivity is involved in the development of late normal tissue reactions after RT. Larger prospective studies are warranted to validate the retrospective findings and to use in vitro cellular assays in the future to predict late normal tissue radiosensitivity and discriminate individuals with marked RT responses.

Hyperbaric oxygen therapy for late radiation-induced tissue toxicity: prospectively patient-reported outcome measures in breast cancer patients

Introduction

This study examines patient reported outcome measures of women undergoing hyperbaric oxygen treatment (HBOT) after breast-conserving therapy.

Method

Included were 57 women treated with HBOT for late radiation-induced tissue toxicity (LRITT) referred in the period January 2014-December 2015. HBOT consisted of (on average) 47 sessions. In total, 80 min of 100 % O₂ was administered under increased pressure of 2.4 ATA. Quality of life was assessed before and after treatment using the European Organization for Research and Treatment of Cancer (EORTC) QLQ-BR23, and a NRS pain score.

Results

Fifty-seven women were available for evaluation before and after treatment. Before HBOT, patients had severe complaints of pain in the arm/shoulder (46 %), swollen arm/hand (14 %), difficulty to raise arm or move it sideways (45 %), pain in the area of the affected breast (67 %), swollen area of the affected breast (45 %), oversensitivity of the affected breast (54 %), and skin problems on/in the area of the affected breast (32 %); post HBOT, severe complaints were still experienced in 17, 7, 22, 15, 13, 15, and 11 % of the women, respectively. Differences were all significant. The NRS pain score improved at least 1 point (range 0–10) in 81 % of the patients (p < 0.05).

Conclusion

In these breast cancer patients treated with HBOT for LRITT, the patient-reported outcomes were positive and improvements were observed. HBOT was a well-tolerated treatment for LRITT and its side-effects were both minimal and reversible.

Impact of hypofractionation and tangential beam IMRT on the acute skin reaction in adjuvant breast cancer radiotherapy

Background

The purpose of the study was to evaluate the impact of multiple prognostic factors on the acute skin reaction in adjuvant breast cancer radiotherapy, in particular the impact of hypofractionation (HF) compared to conventional fractionation (CF) and tangential beam (TB) IMRT compared to three-dimensional conformal radiotherapy (3DCRT).

Methods

Two-hundred and sixty-six breast cancer patients with postoperative radiotherapy after breast conserving surgery or mastectomy were retrospectively evaluated. Patients were treated with HF (15 fractions of 2.67 Gy; n = 121) or CF (28 fractions of 1.8 Gy or 25 fractions of 2.0 Gy; n = 145) and TB-IMRT (n = 151) or 3DCRT (n = 115). The acute skin reactions were prospectively assessed using the CTCAE v4 grading scale. Ordinal regression analysis was used to assess the impact of possible prognostic factors on the maximal acute skin reaction.

Results

Grade 2 skin reactions were observed in 19 % of the patients treated with CF compared to 2 % treated with HF. On univariate analysis, the fractionation regimen, the PTV (breast versus chest wall), the volume of the PTV and the body mass index were significant prognostic factors for the maximum acute skin reaction. On multivariate analysis, the fractionation regimen (p < 0.00001) and the volume of the PTV (p = 0.0002) remained as independent significant factors.

Conclusions

Our data suggest that HF is associated with a significantly reduced maximal acute skin reaction compared to CF.

Predictive parameters for selection of electronic tissue compensation radiotherapy in early-stage breast cancer patients after breast-conserving surgery

Electronic tissue compensation (eComp) is an external beam planning technique allowing user to manually generate dynamic beam fluence to produce more uniform or modulated dose distribution. In this study, we compared the effectiveness between conventional three-dimensional conformal radiotherapy (3DCRT) and eComp for whole breast irradiation. 3DCRT and eComp planning techniques were used to generate treatment plans for 60 whole breast patients, respectively. The planning goal was to cover 95% of the planning target volume (PTV) with 95% of the prescription dose while minimizing doses to lung, heart, and skin. Comparing to 3DCRT plans, on the average, eComp treatment planning process was about 7 minutes longer, but resulted in lower lung V20Gy, lower mean skin dose, with similar heart dose. The benefits were more pronounced for larger breast patients. Statistical analyses were performed between critical organ doses and patient anatomic features, i.e., central lung distance (CLD), maximal heart distance (MHD), maximal heart length (MHL) and breast separation (BS) to explore any correlations and planning method selection. It was found that to keep the lung V20Gy lower than 20% and mean skin dose lower than 85% of the prescription dose, eComp was the preferred method for patients with more than 2.3 cm CLD or larger than 22.5 cm BS. The study results may be useful in providing a handy criterion in clinical practice allowing us to easily choose between different planning techniques to satisfy the planning goal with minimal increase in complexity and cost.

Does breast composition influence late adverse effects in breast radiotherapy?

BACKGROUND

Large breast size is associated with increased risk of late adverse effects after surgery and radiotherapy for early breast cancer. It is hypothesised that effects of radiotherapy on adipose tissue are responsible for some of the effects seen. In this study, the association of breast composition with late effects was investigated along with other breast features such as fibroglandular tissue distribution, seroma and scar.

METHODS

The patient dataset comprised of 18 cases with changes in breast appearance at 2 years follow-up post-radiotherapy and 36 controls with no changes, from patients entered into the FAST-Pilot and UK FAST trials at The Royal Marsden. Breast composition, fibroglandular tissue distribution, seroma and scar were assessed on planning CT scan images and compared using univariate analysis. The association of all features with late-adverse effect was tested using logistic regression (adjusting for confounding factors) and matched analysis was performed using conditional logistic regression.

RESULTS

In univariate analyses, no statistically significant differences were found between cases and controls in terms of breast features studied. A statistically significant association (p < 0.05) between amount of seroma and change in photographic breast appearance was found in unmatched and matched logistic regression analyses with odds ratio (95% CI) of 3.44 (1.28-9.21) and 2.57 (1.05-6.25), respectively.

CONCLUSIONS

A significant association was found between seroma and late-adverse effects after radiotherapy although no significant associations were noted with breast composition in this study. Therefore, the cause for large breast size as a risk factor for late effects after surgery and optimally planned radiotherapy remains unresolved.

Different methods for target volume delineation of glandular breast tissue following breast-conserving surgery in breast cancer: A comparative study

The present study aimed to investigate an optimal and feasible method for delineating the target volume of glandular breast tissue following breast-conserving surgery. A total of 15 patients who underwent radiotherapy following breast-conserving surgery were recruited into the study. Clinical target volume was delineated by the following three methods based on computed tomography (CT): Anatomical landmarks (CTVan), breast palpation (CTVpa) and CT scan images (CTVgl). The target volume, degree of inclusion (DI) and conformal index (CI) defined by these methods were compared. The difference was significant between CTVan and CTVgl, and CTVpa and CTVgl (P<0.0001). The CI between CTVan and CTVpa was 0.644±0.122, significantly higher than that between CTVan and CTVgl (0.264±0.108; P<0.0001) or between CTVpa and CTVgl (0.328±0.115; P<0.0001). The DI of CTVpa in CTVan was 0.890±0.08 and the opposite was 0.709±0.144, while that of DI of CTVgl in CTVan or CTVpa was 0.994±0.005 and 0.989±0.008, respectively. The boundary difference between CTVan and CTVpa was 3.35±7.23, 5.57±13.37, 1.75±11.62 and 11.25±4.07 mm for the medial, lateral, cephalic and caudal boundaries, respectively. A significant difference was observed in the target volume of the breast defined by the three methods. The target volume defined by CTVgl was significantly smaller than that identified by the other two methods. Overall, the combination of palpation marks and anatomical landmarks to define the contouring scope of the breast was indicated to be a relatively rational method for delineating the target volume of the breast.