A Retrospective Analysis of Dose Distribution and Toxicity in Patients with Left Breast Cancer Treated with Adjuvant Intensity-Modulated Radiotherapy: Comparison with Three-Dimensional Conformal Radiotherapy

Surface dose measurement by optically stimulated luminescent dosimeter: A phantom study

INTRODUCTION

Radiotherapy is the standard treatment for breast cancer patients after surgery. However, radiotherapy can cause side effects such as dry and moist desquamation of the patient's skin. The dose calculation from a treatment planning system (TPS) might also be inaccurate. The purpose of this study is to measure the surface dose on the CIRS thorax phantom by an optically stimulated luminescent dosimeter (OSLD).

METHODS

The characteristics of OSLD were studied in terms of dose linearity, reproducibility, and angulation dependence on the solid water phantom. To determine the surface dose, OSLD (Landauer lnc., USA) was placed on 5 positions at the CIRS phantom (Tissue Simulation and Phantom Technology, USA). The five positions were at the tip, medial, lateral, tip-medial, and tip-lateral. Then, the doses from OSLD and TPS were compared.

RESULTS

The dosimeter's characteristic test was good. The maximum dose at a depth of 15 mm was 514.46 cGy, which was at 100%. The minimum dose at the surface was 174.91 cGy, which was at 34%. The results revealed that the surface dose from TPS was less than the measurement. The percent dose difference was -2.17 ± 6.34, -12.08 ± 3.85, and -48.71 ± 1.29 at the tip, medial, and lateral positions, respectively. The surface dose from TPS at tip-medial and tip-lateral was higher than the measurement, which was 12.56 ± 5.55 and 10.45 ± 1.76 percent dose different, respectively.

CONCLUSION

The percent dose difference is within the acceptable limit, except for the lateral position because of the body curvature. However, OSLD is convenient to assess the radiation dose, and further study is to measure in vivo.

IMPLICATION FOR PRACTICE

The OSL NanoDot dosimeter can be used for dose validation with a constant setup location. The measurement dose is higher than the dose from TPS, except for some tilt angles.

Organ-sparing techniques and dose-volume constrains used in breast cancer radiation therapy - Results from European and Latin American surveys

Background

Advances in local and systemic therapies have improved the outcomes of patients with breast cancer (BC), leading to a possible increased risk for postoperative radiation therapy (RT) late adverse events. The most adequate technologies and dose constraints for organs at risk (OAR) in BC RT have yet to be defined.

Methods

An online survey was distributed to radiation oncologists (ROs) practicing in Europe and Latin America including the Caribbean (LAC) through personal contacts, RO and BC professional groups' networks. Demographic data and clinical practice information were collected.

Results

 The study included 585 responses from ROs practicing in 57 different countries. The most frequently contoured OAR by European and LAC participants were the whole heart (96.6 % and 97.7 %), the ipsilateral (84.3 % and 90.8 %), and contralateral lung (71.3 % and 77.4 %), whole lung (69.8 % and 72.9 %), and the contralateral breast (66.4 % and. 83.2 %). ESTRO guidelines were preferred in Europe (33.3 %) and the RTOG contouring guideline was the most popular in LAC (62.2 %), while some participants used both recommendations (13.2 % and 19.2 %). IMRT (68.6 % and 59.1 %) and VMAT (65.6 % and 60.2 %) were the preferred modalities used in heart sparing strategies, followed by deep inspiration breath-hold (DIBH) (54.8 % and 37.4 %) and partial breast irradiation (PBI) (41.6 % and 24.6 %). Only a small percentage of all ROs reported the dose-volume constraints for OAR used in routine clinical practice. A mean heart dose (Heart-Dmean) between 4 and 5 Gy was the most frequently reported parameter (17.2 % and 39.3 %).

Conclusion

 The delineation approaches and sparing techniques for OAR in BC RT vary between ROs worldwide. The low response rate to the dose constraints subset of queries reflects the uncertainty surrounding this topic and supports the need for detailed consensus recommendations in the clinical practice.

Radiation Dermatitis and Pneumonitis in Patients Irradiated for Breast Cancer

BACKGROUND/AIM

Adjuvant radiotherapy (RT) for breast cancer can be associated with acute dermatitis (ARD) and pneumonitis (RP). Prevalence and risk factors were characterized.

PATIENTS AND METHODS

This study included 489 breast cancer patients receiving adjuvant RT with conventional fractionation (CF) ± sequential or simultaneous integrated boost, or hypo-fractionation ± sequential boost. RT-regimen and 15 characteristics were investigated for grade ≥2 ARD and RP.

RESULTS

Prevalence of grade ≥2 ARD and RP was 25.3% and 2.5%, respectively. On univariate analyses, ARD was significantly associated with CF and radiation boost (p<0.0001), age ≤60 years (p=0.008), Ki-67 ≥15% (p=0.012), and systemic treatment (p=0.002). On multivariate analysis, RT-regimen (p<0.0001) and age (p=0.009) were associated with ARD. Chronic inflammatory disease was significantly associated with RP on univariate (p=0.007) and multivariate (p=0.016) analyses.

CONCLUSION

Risk factors for grade ≥2 ARD and RP were determined that may help identify patients who require closer monitoring during and after RT.

Radiation-induced skin and heart toxicity in patients with breast cancer treated with adjuvant proton radiotherapy: a comparison with photon radiotherapy

This study aimed to investigate the dose parameters and incidence of radiotherapy (RT)-associated toxicity in patients with left breast cancer (LBC) treated with proton-RT, compared with photon-RT. We collected data from 111 patients with LBC who received adjuvant RT in our department between August 2021 and March 2023. Among these patients, 24 underwent proton-RT and 87 underwent photon-RT. In addition to the dosimetric analysis for organs at risk (OARs), we measured NT-proBNP levels before and after RT. Our data showed that proton-RT improved dose conformity and reduced doses to the heart and lungs and was associated with a lower rate of increased NT-proBNP than did photon-RT. Regarding skin toxicity, the Dmax for 1 c.c. and 10 c.c. and the average dose to the skin-OAR had predictive roles in the risk of developing radiation-induced dermatitis. Although pencil beam proton-RT with skin optimization had a dose similar to that of skin-OAR compared with photon-RT, proton-RT still had a higher rate of radiation dermatitis (29%) than did photon RT (11%). Using mice 16 days after irradiation, we demonstrated that proton-RT induced a greater increase in interleukin 6 and transforming growth factor-β1 levels than did photon-RT. Furthermore, topical steroid ointment reduced the inflammatory response and severity of dermatitis induced by RT. In conclusion, we suggest that proton-RT with skin optimization spares high doses to OARs with acceptable skin toxicity. Furthermore, prophylactic topical steroid treatment may decrease radiation dermatitis by alleviating proton-induced inflammatory responses in vivo.

Critical Evaluation of Secondary Cancer Risk After Breast Radiation Therapy with Hybrid Radiotherapy Techniques

Background

As hybrid radiotherapy technique can effectively balance dose distribution between targets and organs, it is necessary to evaluate the late effects related to radiotherapy. The aim of the study was to calculate and provide individual estimates of the risks for hybrid radiotherapy techniques in breast cancer patients.

Methods

Whole-breast irradiation was performed in 43 breast cancer patients by using 3D conformal, intensity-modulated and hybrid techniques. The excess absolute risk (EAR), lifetime attributable risk (LAR) and normal tissue complication probability (NTCP) were calculated to estimate risks in organs. The risk variability in contralateral breast was assessed by using the patient's anatomic parameters.

Results

Compared with IMRT and FinF, hybrid techniques achieved satisfactory dose distribution and comparable or lower estimated risks in organs. The LAR was estimated to be up to 0.549% for contralateral lung with advantages of tangential techniques over H-VMAT. For ipsilateral lung, the LAR was estimated to be up to 9.021%, but lower in H-VMAT and FinF without significant difference. The risk of thyroid was negligible in overall estimation. For contralateral breast, the LAR was estimated to be up to 0.865% with advantages of MH-IMRT and H-VMAT over TF-IMRT. The fraction of individual variability could be explained by using anatomic parameters of minimum breast distance (MBD) and minimum target concave angle (θ_MTCA). NTCP for all analyzed endpoints was significantly higher in TF-IMRT relative to FinF and hybrid techniques, while TH-IMRT and H-VMAT were presenting lower toxicity risk. However, MH-IMRT presented a higher probability of toxicity in lung. For most cases, H-VMAT demonstrated a benefit for contralateral breast, heart and lung sparing.

Conclusion

The optimal treatment should be performed individually according to anatomic parameters and balances between EAR and NTCP. Individual assessment may assist in achieving optimal balances between targets and organs as well as supporting clinical decision-making processes.

Robustness of VMAT to setup errors in postmastectomy radiotherapy of left-sided breast cancer: Impact of bolus thickness

BACKGROUND

Volumetric modulated arc therapy (VMAT) with varied bolus thicknesses has been employed in postmastectomy radiotherapy (PMRT) of breast cancer to improve superficial target coverage. However, impact of bolus thickness on plan robustness remains unclear.

METHODS

The study enrolled ten patients with left-sided breast cancer who received radiotherapy using VMAT with 5 mm and 10 mm bolus (VMAT-5B and VMAT-10B). Inter-fractional setup errors were simulated by introducing a 3 mm shift to isocenter of the original plans in the anterior-posterior, left-right, and inferior-superior directions. The plans (perturbed plans) were recalculated without changing other parameters. Dose volume histograms (DVH) were collected for plan evaluation. Absolute dose differences in DVH endpoints for the clinical target volume (CTV), heart, and left lung between the perturbed plans and the original ones were used for robustness analysis.

RESULTS

VMAT-10B showed better target coverage, while VMAT-5B was superior in organs-at-risk (OARs) sparing. As expected, small setup errors of 3 mm could induce dose fluctuations in CTV and OARs. The differences in CTV were small in VMAT-5B, with a maximum difference of -1.05 Gy for the posterior shifts. For VMAT-10B, isocenter shifts in the posterior and right directions significantly decreased CTV coverage. The differences were -1.69 Gy, -1.48 Gy and -1.99 Gy, -1.69 Gy for ΔD95% and ΔD98%, respectively. Regarding the OARs, only isocenter shifts in the posterior, right, and inferior directions increased dose to the left lung and the heart. Differences in VMAT-10B were milder than those in VMAT-5B. Specifically, mean heart dose were increased by 0.42 Gy (range 0.10 ~ 0.95 Gy) and 0.20 Gy (range -0.11 ~ 0.72 Gy), and mean dose for the left lung were increased by 1.02 Gy (range 0.79 ~ 1.18 Gy) and 0.68 Gy (range 0.47 ~ 0.84 Gy) in VMAT-5B and VMAT-10B, respectively. High-dose volumes in the organs were increased by approximate 0 ~ 2 and 1 ~ 3 percentage points, respectively. Nevertheless, most of the dosimetric parameters in the perturbed plans were still clinically acceptable.

CONCLUSIONS

VMAT-5B appears to be more robust to 3 mm setup errors than VMAT-10B. VMAT-5B also resulted in better OARs sparing with acceptable target coverage and dose homogeneity. Therefore 5 mm bolus is recommended for PMRT of left-sided breast cancer using VMAT.

Systematic risk analysis of radiation pneumonitis in breast cancer: role of cotreatment with chemo-, endocrine, and targeted therapy

PURPOSE

A major complication of sequential and concomitant chemoradiation in breast cancer treatment is interstitial pneumonitis induced by radiation therapy (RT), systemic therapy, or a combination of both. Dose and volume of co-irradiated lung tissue directly correlate with the risk of radiation pneumonitis. Especially in case of combined treatment, it is often unclear which of the used therapeutic agents promote pneumonitis.

METHODS

This was a prospective monocentric study including 396 breast cancer patients. A systematic analysis of single and combined therapeutic measures was performed in order to identify treatment-related factors enhancing the risk of pneumonitis post RT.

RESULTS

Overall incidence of pneumonitis of any grade was 38%; 28% were asymptomatic (grade 1) and 10% were symptomatic (> grade 1). Pneumonitis > grade 2 did not occur. Beside age, smoking status, and mean lung dose, the combined treatment with goserelin and tamoxifen significantly enhanced the risk of pneumonitis in a supra-additive pattern (odds ratio [OR] 4.38), whereas each agent alone or combined with other drugs only nonsignificantly contributed to a higher pneumonitis incidence post RT (OR 1.52 and OR 1.16, respectively). None of the other systemic treatments, including taxanes, increased radiation pneumonitis risk in sequential chemoradiation.

CONCLUSION

Common treatment schedules in sequential chemoradiation following breast-conserving surgery only moderately increase lung toxicity, mainly as an asymptomatic complication, or to a minor extent, as transient pneumonitis ≤ grade 2. However, combined treatment with tamoxifen and the LHRH analog goserelin significantly increased the risk of pneumonitis in breast cancer patients after chemoradiation. Thus, closer surveillance of involved patients is advisable.

Skin Surface Dose for Whole Breast Radiotherapy Using Personalized Breast Holder: Comparison with Various Radiotherapy Techniques and Clinical Experiences

Purpose: Breast immobilization with personalized breast holder (PERSBRA) is a promising approach for normal organ protection during whole breast radiotherapy. The aim of this study is to evaluate the skin surface dose for breast radiotherapy with PERSBRA using different radiotherapy techniques. Materials and methods: We designed PERSBRA with three different mesh sizes (large, fine and solid) and applied them on an anthropomorphic(Rando) phantom. Treatment planning was generated using hybrid, intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) techniques to deliver a prescribed dose of 5000 cGy in 25 fractions accordingly. Dose measurement with EBT3 film and TLD were taken on Rando phantom without PERSBRA, large mesh, fine mesh and solid PERSBRA for (a) tumor doses, (b) surface doses for medial field and lateral field irradiation undergoing hybrid, IMRT, VMAT techniques. Results: The tumor dose deviation was less than five percent between the measured doses of the EBT3 film and the TLD among the different techniques. The application of a PERSBRA was associated with a higher dose of the skin surface. A large mesh size of PERSBRA was associated with a lower surface dose. The findings were consistent among hybrid, IMRT, or VMAT techniques. Conclusions: Breast immobilization with PERSBRA can reduce heart toxicity but leads to a build-up of skin surface doses, which can be improved with a larger mesh design for common radiotherapy techniques.

Effectiveness of Therapeutic Exercise and Patient Education on Cancer-Related Fatigue in Breast Cancer Survivors: A Randomised, Single-Blind, Controlled Trial with a 6-Month Follow-Up

This study aimed to determine the effectiveness of therapeutic exercise plus patient therapeutic education on perceived fatigue, functional capacity and pain in breast cancer survivors with cancer-related fatigue. A randomised, single-blind, clinical trial was conducted with a total of 80 breast cancer survivors who presented cancer-related fatigue. Women were randomised into a supervised therapeutic exercise group (STE-G) (n = 40) or an unsupervised exercise group (UE-G) (n = 40). Both interventions included patient therapeutic education and were delivered in three sessions per week over eight weeks. The main outcome was perceived fatigue as assessed by the Spanish version of the Functional Assessment of Chronic Illness Therapy-Fatigue subscale (FACIT-F). Other evaluated outcomes were pain measured on a visual analogue scale, and distance measured using the 6-Minute Walk Test. Data were collected at baseline, immediately post-intervention, and at three and six months after baseline. Significantly greater improvements across all variables were observed in the STE-G throughout the entire follow-up period with the exception of pain. Conclusions: A supervised therapeutic exercise program plus patient therapeutic education significantly reduce perceived fatigue and increase functional capacity in breast cancer survivors suffering from cancer-related fatigue compared to an unsupervised physical exercise program based on individual preferences with patient therapeutic education.

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.

Role of Nutritional Status in the Treatment Outcome for Esophageal Squamous Cell Carcinoma

Undernourishment is reported to impair treatment response, further leading to poor prognosis for cancer patients. We aimed to investigate the role of nutritional status on the prognosis of squamous cell carcinoma (SCC) of the esophagus, and its correlation with anticancer immune responsiveness. We retrospectively reviewed 340 esophageal-SCC patients who completed curative treatment and received a nutrition evaluation by the Patient-Generated Subjective Global Assessment (PGSGA) score at the beginning and completion of neoadjuvant treatment at our hospital. The correlation between the nutritional status and various clinicopathological parameters and prognosis were examined. In addition, the role of nutritional status in the regulation of the anticancer immune response was also assessed in cancer patients and in a 4-nitroquinoline 1-oxide (4NQO)-induced esophageal tumor model. Our data revealed that malnutrition (patients with a high PGSGA score) was associated with advanced stage and reduced survival rate. Patients in the group with a high PGSGA score were correlated with the higher neutrophil-to-lymphocyte ratio, higher proportion of myeloid-derived-suppressor cells (MDSC) and increased IL-6 level. Furthermore, surgical resection brought the survival benefit to patients in the low PGSGA group, but not for the malnourished patients after neoadjuvant treatment. Using a 4NQO-induced tumor model, we found that nutrition supplementation decreased the rate of invasive tumor formation and attenuated the immune-suppressive microenvironment. In conclusion, malnutrition was associated with poor prognosis in esophageal-SCC patients. Nutritional status evaluated by PGSGA may be useful to guide treatment decisions in clinical practice. Nutritional supplementation is suggested to improve prognosis, and it might be related to augmented anticancer immune response.

CT findings of acute radiation-induced pneumonitis in breast cancer

OBJECTIVES

To evaluate the CT findings of acute radiation pneumonitis (RP) in breast cancer patients undergoing post-operative radiotherapy, and to analyze clinicodosimetric factors associated with acute RP.

METHODS

Between 2015 and 2017, 61 patients with breast cancer who underwent follow-up chest CT at 3 months after radiotherapy were analyzed. The degree of acute RP on CT was evaluated by the change of extent and scoring system (grade 0, no RP; Grade 1, ground-glass opacities (GGOs); Grade 2, GGOs and/or consolidations; Grade 3, clear focal consolidation; Grade 4, dense consolidation). The dosimetric parameters were calculated from the dose-volume histogram of RT.

RESULTS

The acute RP on CT was scored as follows: Grade 0, in 37.7%, Grade 1 in 13.1%, Grade 2 in 44.3%, and Grade 3 in 4.9%. The median extent of RP in patients with Grades 1 to 3 was 6.2 ml (range, 0.2-95.9). There were no clinicodosimetric factors significantly associated with the presence of RP or its severity. One patient developed symptomatic RP.

CONCLUSION

This study showed no correlation between acute RP and clinicodosimetric factors, and acute RP based on CT findings were much more common than symptomatic RP.

ADVANCES IN KNOWLEDGE

CT findings of acute RP or extent of RP were not significantly related to clinicodosimetric factors in breast cancer patients.