Hypofractionated radiotherapy for early breast cancer: Review of phase III studies

Large scale experience of two ultrahypofractionated 5 fractions regimes after breast conserving surgery from a single centre

PURPOSE

Ultra-hypofractionation breast radiotherapy is a safe alternative to moderate hypofractionation. This study reports the results of two ultrahypofractionated regimens used in clinical practice in a high-volume radiotherapy center in terms of efficacy and of tolerance.

METHODS

we included all patients treated in an adjuvant setting with five fractions after breast conserving surgery (BCS), for a histologically-confirmed invasive or in situ breast carcinoma. Radiotherapy regimens after BCS were either a 5-week schedule with 5 weekly fractions of 5,7 Gy or a one-week schedule with 5 daily fractions of 5,2 Gy. Adverse events were recorded and local-relapse free survival (LRFS), locoregional-relapse free survival (LRRFS), metastasis-free survival (MFS), for breast-cancer specific survival (BCSS) and overall survival (OS) were evaluated.

RESULTS

Between December 2014 and December 2022, 396 patients (400 breasts) were treated with ultrahypofractionated radiotherapy. Five-year LRFS was 98.8% (95% confidence interval: 97.1%-100%), and 5-year OS was 96.0% (95%CI: 92.6-99.5%). Age was statistically associated with OS in univariate analysis (HR: 1.16, 95%CI: 1.04-1.42, p = .01). Four patients (1.0%) experienced acute grade 3 radiation-induced adverse events, and 8 patients (2.3%) acute grade 2 toxicities. Twenty-three patients (5.8%) experienced late toxicity, all of them being graded as grade 1. The use of the 5.7 Gy-weekly-fraction regimen and the delivery of a tumor bed boost were significantly associated with acute radiodermatitis (p < .01; p = .02; respectively) and late fibrosis (p < .01; p = .049; respectively).

CONCLUSIONS

ultrahypofractionated radiotherapy was associated with an excellent tumor control rate in our 'real-life' cohort with low-risk breast cancer patients. However, delivery of a tumor bed boost and using weekly 5.7-Gy fractions were associated with an increased risk of acute and late cutaneous toxicities.

Hypofractionated Whole-Breast Irradiation Focus on Coronary Arteries and Cardiac Toxicity-A Narrative Review

Breast cancer is the most common cancer among women worldwide, which is often treated with radiotherapy. Whole breast irradiation (WBI) is one of the most common types of irradiation. Hypo-fractionated WBI (HF-WBI) reduces the treatment time from 5 to 3 weeks. Recent radiobiological and clinical evidence recommended the use of HF-WBI regardless of the age or stage of disease, and it is proven that hypo-fractionation is non-inferior to conventional fractionation regimen irradiation. However, some studies report an increased incidence of heart-related deaths in the case of breast irradiation by hypo-fractionation, especially in patients with pre-existing cardiac risk factors at the time of treatment. Due to the new technical possibilities of radiotherapy techniques, HF-WBI can reduce the risk of cardiac toxicity by controlling the doses received both by the heart and by the anatomical structures of the heart. The radiobiological “double trouble”, in particular “treble trouble”, for hypo-fractionated regimen scan be avoided by improving the methods of heart sparing based on image-guided irradiation (IGRT) and by using respiration control techniques so that late cardiac toxicity is expected to be limited. However, long-term follow-up of patients treated with HF-WBI with modern radiotherapy techniques is necessary considering the progress of systemic therapy, which is associated with long-term survival, and also the cardiac toxicity of new oncological treatments. The still unknown effects of small doses spread in large volumes on lung tissue may increase the risk of second malignancy, but they can also be indirectly involved in the later development of a heart disease. It is also necessary to develop multivariable radiobiological models that include histological, molecular, clinical, and therapeutic parameters to identify risk groups and dosimetric tolerance in order to limit the incidence of late cardiac events. MR-LINAC will be able to offer a new standard for reducing cardiac toxicity in the future, especially in neoadjuvant settings for small tumors.

Dual-Color Plasmonic Nanosensor for Radiation Dosimetry

Radiation dosimeters are critical for accurately assessing the levels of radiation exposure of tumor sites and surrounding tissues and for optimizing therapeutic interventions as well as for monitoring environmental exposure. To fill the need for a simple, user-friendly, and inexpensive dosimeter, we designed an innovative colorimetric nanosensor-based assay for detecting ionizing radiation. We show that hydroxyl radicals generated by ionizing radiation can be used to etch gold nanorods (AuNRs) and silver nanoprisms (AgNPRs), yielding reproducible color changes for radiation dose detection in the range of 50-2000 rad, broad enough to cover doses used in hyperfractionated, conventional, and hypofractionated radiotherapy. This range of doses detected by this assay correlates with radiation-induced DNA damage response in mammalian cells. Furthermore, this AuNR- and AgNPR-based sensing platform has been established in a paper format that can be readily adopted for a wide range of applications and translation.

Simultaneous Integrated Boost in Once-weekly Hypofractionated Radiotherapy for Breast Cancer in the Elderly: Preliminary Evidence

AIM

To evaluate once-weekly hypofractionated radiotherapy in elderly patients affected by early breast cancer, reporting acute and late toxicity profiles, and treatment feasibility.

PATIENTS AND METHODS

Fifty patients were treated with a hypofractionated regimen: 28.5±2.5 Gy in five fractions at one fraction weekly. Simultaneous integrated boost (SIB) to the tumor bed in high-risk cases.

INCLUSION CRITERIA

patients over 70 years old, pT1-2, N0-1a. Acute and late toxicities were assessed based on Radiation Therapy Oncology Group.

RESULTS

The median follow-up was 20 months and the median patient age was 79 years. SIB was added for 22 patients (44%). Grade 3-4 acute cutaneous toxicities were not observed; grade 2 toxicity occurred only in four patients (8%). Late subcutaneous tissue toxicity consisted of grade 2 fibrosis in two patients (4%), grade 1 in five (10%) and grade 0 in 41(85%).

CONCLUSION

Limiting fraction numbers with a safer profile may improve the management of breast cancer for the elderly.

Comparison of Local Recurrence Among Early Breast Cancer Patients Treated With Electron Intraoperative Radiotherapy vs Hypofractionated Photon Radiotherapy an Observational Study

Purpose

To evaluate local recurrence (LR) in women with early breast cancer (BC) who underwent intraoperative radiation therapy with electrons particles (IORT-E) or adjuvant hypofractionated external radiotherapy (HYPOFX).

Materials and methods

We retrospectively analyzed 470 patients with early BC treated at our center from September 2009 to December 2012. 235 women were treated with breast-conserving surgery and immediate IORT-E (21 Gy/1 fraction) while 235 patients underwent wide excision followed by hypofractionated whole-breast irradiation. Radiotherapy modality was chosen according to an individualized decision based on tumor features, stage, technical feasibility, age, and acceptance to be enrolled in the IORT-E group.

Results

After a median follow-up of 6 years, we observed 8 (3.4%) and 1 (0.42%) LR in the IORT-E and in the HYPOFX group (p = 0.02), respectively. The two groups differed in the prevalence of clinical characteristics (p < 0.05): age, tumor size, surgical margins, receptors, ki67, and histology. 4 and 1 woman in the IORT-E and HYPOFX group died of BC, respectively (p = 0.167). OS and DFS hazard ratio [HR] were 2.14 (95% IC, 1.10–4.15) and 2.09 (95% IC, 1.17–3.73), respectively.

Conclusion

Our comparison showed that IORT-E and HYPOFX are two effective radiotherapy modalities after conservative surgery in early BC. However, at 6 years a significant higher rate of LR occurred in patients submitted to IORT-E with respect to HYPOFX. This finding may be correlated to some subsets of patients who, depending on the biological characteristics of the BC, may be less suitable to IORT-E.

Accelerated partial breast irradiation compared with whole breast radiation therapy: a breast cancer cohort study measuring change in radiation side-effects severity and quality of life

PURPOSE

Radiotherapy (RT) after breast-conserving surgery for early-stage breast cancer patients has similar survival benefits with whole breast RT (WBRT) or accelerated partial breast irradiation (APBI). However, the impact of RT type and side-effects severity on change in quality of life (QOL) is unknown. We examined changes in RT side-effects severity and QOL by RT type.

METHODS

We analyzed data from a cohort of 285 newly diagnosed early-stage breast cancer patients with tumor size ≤3.0 cm and lymph node-negative disease. Patients (93 [32.6%] stage 0; 49 [17.2%] non-white; mean age = 59.3 years) completed four interviews (6 weeks, 6, 12, and 24 months) after definitive surgical treatment. We measured severity of RT side effects, fatigue and skin irritation, using a 5-point scale (1 "not at all" to 5 "all the time") and measured QOL using the Functional Assessment of Cancer Therapy-Breast (FACT-B) and RAND 36-item Health Survey Vitality subscale. Repeated-measures analysis of covariance of each outcome controlled for demographic, clinical/treatment, and psychosocial factors.

RESULTS

Patients initiated RT by 6 months (113 received APBI; 172 received WBRT) and completed RT by 12 months. Patients receiving WBRT (vs. APBI) reported greater increase in fatigue and skin irritation severity from 6-week to 6-month interviews (each P < 0.001). Improvement in neither total FACT-B nor Vitality differed significantly by RT type over 2-year follow-up.

CONCLUSIONS

Findings suggest that early-stage breast cancer patients can benefit from less-severe, short-term side effects of APBI with no differential impact on QOL change within 2-year follow-up.

Predictive parameters in hypofractionated whole-breast 3D conformal radiotherapy according to the Ontario Canadian trial

AIM

To evaluate the possible role of dosimetric parameters according Normal Tissue Complication Probability (NTCP) model as predictive of late toxicity and cosmesis in hypofractionated whole-breast three-dimensional conformal radiotherapy.

PATIENTS AND METHODS

A retrospective analysis on 215 consecutive early breast cancer patients treated with breast conserving surgery and adjuvant hypofractionated whole-breast radiotherapy (according the Ontario Canadian trial), with a 6 years median follow-up was conducted. To assess the impact of 10%-20% dose hotspots on different percent values of planning target volume (PTV) of the breast, we retrospectively employed the NTCP model of Lyman. PTV breast (PTVbr), V110 were identified. For statistical analysis the χ² and paired t-test were used to find a correlation between late skin and subcutaneous toxicity and cosmetic outcome with dosimetrical parameters Multivariate analysis was performed with the aim to assess independently the impact of dosimetric and clinical parameters on late toxicity and cosmesis using Pearson's covariance.

RESULTS

Late skin toxicity was recorded in 47/215 (22%); and G3 toxicity occurred in 11 patients (5%). Cosmesis with excellent-good score was found in 172 patients (80%) while fair-poor score was found in 43 patients (20%). In univariate χ² analysis the V110 >10% of the PTV breast significantly correlated with higher toxicity (P<0.005, OR 9.60 [CI 3.89-23.72]). Cosmesis related to V110 >10% and PTV breast volume over 1,300 cc was significant at multivariate analysis (P<0.005, OR 6.07 [CI 2.36-15.59]).

CONCLUSION

To safely use one of the most important whole-breast hypofractionated radiotherapy schedules, we found some predictive paramaters on the basis of NTCP model by Lyman. These parameters may be useful in selection of elegible patients.

Oncoplastic breast surgery in the setting of breast-conserving therapy: A systematic review

Breast-conserving therapy (BCT), or breast-conserving surgery with adjuvant radiation therapy, has become a standard treatment alternative to mastectomy for women with early-stage breast cancer after many long-term studies have reported comparable rates of overall survival and local control. Oncoplastic breast surgery in the setting of BCT consists of various techniques that allow for an excision with a wider margin and a simultaneous enhancement of cosmetic sequelae, making it an ideal breast cancer surgery. Because of the parenchymal rearrangement that is routinely involved in oncoplastic techniques, however, the targeted tissue can be relocated, thus posing a challenge to localize the tumor bed for radiation planning. The goals of this systematic review are to address the challenges, outcomes, and cosmesis of oncoplastic breast surgery in the setting of BCT.

Minimizing metastatic risk in radiotherapy fractionation schedules

Metastasis is the process by which cells from a primary tumor disperse and form new tumors at distant anatomical locations. The treatment and prevention of metastatic cancer remains an extremely challenging problem. This work introduces a novel biologically motivated objective function to the radiation optimization community that takes into account metastatic risk instead of the status of the primary tumor. In this work, we consider the problem of developing fractionated irradiation schedules that minimize production of metastatic cancer cells while keeping normal tissue damage below an acceptable level. A dynamic programming framework is utilized to determine the optimal fractionation scheme. We evaluated our approach on a breast cancer case using the heart and the lung as organs-at-risk (OAR). For small tumor [Formula: see text] values, hypo-fractionated schedules were optimal, which is consistent with standard models. However, for relatively larger [Formula: see text] values, we found the type of schedule depended on various parameters such as the time when metastatic risk was evaluated, the [Formula: see text] values of the OARs, and the normal tissue sparing factors. Interestingly, in contrast to standard models, hypo-fractionated and semi-hypo-fractionated schedules (large initial doses with doses tapering off with time) were suggested even with large tumor α/β values. Numerical results indicate the potential for significant reduction in metastatic risk.

Breast cancer in young women in southern Tunisia: Anatomical study and clinical prognostic factors: About a series of 83 patients

PURPOSE

To define epidemiological, clinical, therapeutic and prognostic factors influencing survival of breast cancer in young women younger than 35 in southern Tunisia.

MATERIAL AND METHODS

This is a retrospective study of 83 patients younger than 35 years and treated within tumors mammary committee of Sfax.

RESULTS

The mean age was 31.7 years. T2 stage, high grade with positive node tumors were frequent. Breast surgery was performed for 73 patients. Chemotherapy was neo-adjuvant, adjuvant and palliative for respectively 10, 62 and 13 patients. Radiotherapy was delivered for 65 patients with curative intent and for 8 metastatic patients. Endocrine therapy was adjuvant in 38 patients and palliative in 6 cases. The overall survival (OS) at 5 years was 66.8%. Pejorative prognostic factors in uni-variate analysis were clinical T stage (T3, T4), and the number of involved lymph nodes.

CONCLUSION

Despite adequate treatment, the prognosis of breast cancer in young women remains worse. Early diagnosis is necessary to promote outcome.

Single high-dose vs. fractionated radiotherapy: Effects on plant growth rates

AIM

To evaluate the differential effects of fractionated vs. high-dose radiotherapy on plant growth.

BACKGROUND

Interest in hypofractionated radiotherapy has increased substantially in recent years as tumours (especially of the lung, prostate, and liver) can be irradiated with ever greater accuracy due to technological improvements. The effects of low-dose ionizing radiation on plant growth have been studied extensively, yet few studies have investigated the effect of high-dose, hypofractionated radiotherapy on plant growth development.

MATERIALS AND METHODS

A total of 150 plants from the genus Capsicum annuum were randomized to receive fractionated radiotherapy (5 doses of 10 Gy each), single high-dose (SHD) radiotherapy (single 50 Gy dose), or no radiotherapy (control group). Irradiation was delivered via linear accelerator and all samples were followed daily for 26 days to assess and compare daily growth.

RESULTS

On day 26, plants in the control, fractionated, and SHD groups had grown to a mean height of 7.55 cm, 4.32 cm, and 2.94 cm, respectively. These differences in overall growth were highly significant (P = 0.005). The SHD group showed the least amount of growth.

CONCLUSIONS

SHD effectively stunts plant growth and development. Despite the evident differences between plant and animal cells, ionizing radiation is believed to work in a similar manner in all biological cells. These findings highlight the need to continue investigating the use of hypofractionated schemes in humans to improve cancer treatment outcomes.

Cost-effectiveness analysis of intraoperative radiation therapy for early-stage breast cancer

BACKGROUND

Shortened courses of radiation therapy have been shown to be similarly effective to whole-breast external-beam radiation therapy (WB-EBRT) in terms of local control. We sought to analyze, from a societal perspective, the cost-effectiveness of two radiation strategies for early-stage invasive breast cancer: single-dose intraoperative radiation therapy (IORT) and the standard 6-week course of WB-EBRT.

METHODS

We developed a Markov decision-analytic model to evaluate these treatment strategies in terms of life expectancy, quality-adjusted life years (QALYs), costs, and the incremental cost-effectiveness ratio over 10 years.

RESULTS

IORT single-dose intraoperative radiation therapy was the dominant, more cost-effective strategy, providing greater quality-adjusted life years at a decreased cost compared with 6-week WB-EBRT. The model was sensitive to health state utilities and recurrence rates, but not costs. IORT was either the preferred or dominant strategy across all sensitivity analyses. The two-way sensitivity analyses demonstrate the need to accurately determine utility values for the two forms of radiation treatment and to avoid indiscriminate use of IORT.

CONCLUSIONS

With less cost and greater QALYs than WB-EBRT, IORT is the more valuable strategy. IORT offers a unique example of new technology that is less costly than the current standard of care option but offers similar efficacy. Even when considering the capital investment for the equipment ($425 K, low when compared with the investments required for robotic surgery or high-dose-rate brachytherapy), which could be recouped after 3-4 years conservatively, these results support IORT as a change in practice for treating early-stage invasive breast cancer.

Primary squamous cell carcinoma of the breast: A rare case report

BACKGROUND

Squamous cells are normally not found inside the breast. Therefore, a primary squamous cell carcinoma of the breast is an exceptional phenomenon and the management of this type of disease is still debated.

AIM

Clinical outcome assessment of a patient with squamous cell carcinoma of the breast.

MATERIALS AND METHODS

We report a case of primary squamous cell carcinoma of the breast (T1cN0M0) in a 51-years-old woman who underwent breast conserving surgery plus adjuvant chemotherapy and radiation therapy (RT).

RESULTS

With a follow up of 43 months, the patient is alive with no evidence of local or distant recurrence. The patient had Grade 2 acute skin toxicity. No late skin or respiratory toxicity was observed.

CONCLUSIONS

Pure primary squamous cell carcinoma of the breast is a rare and aggressive disease, often treatment-refractory. Our case shows that the addition of RT after breast conserving surgery, allows to achieve a high local control without adding severe toxicity. A multidisciplinary approach seems to be the optimal management for early stages in this rare disease.