DEGRO guideline for personalized radiotherapy of brain metastases and leptomeningeal carcinomatosis in patients with breast cancer.

PURPOSE: The aim of this review was to evaluate the existing evidence for radiotherapy for brain metastases in breast cancer patients and provide recommendations for the use of radiotherapy for brain metastases and leptomeningeal carcinomatosis. MATERIALS AND METHODS: For the current review, a PubMed search was conducted including articles from 01/1985 to 05/2023. The search was performed using the following terms: (brain metastases OR leptomeningeal carcinomatosis) AND (breast cancer OR breast) AND (radiotherapy OR ablative radiotherapy OR radiosurgery OR stereotactic OR radiation). CONCLUSION AND RECOMMENDATIONS: Despite the fact that the biological subtype of breast cancer influences both the occurrence and relapse patterns of breast cancer brain metastases (BCBM), for most scenarios, no specific recommendations regarding radiotherapy can be made based on the existing evidence. For a limited number of BCBM (1-4), stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (SRT) is generally recommended irrespective of molecular subtype and concurrent/planned systemic therapy. In patients with 5-10 oligo-brain metastases, these techniques can also be conditionally recommended. For multiple, especially symptomatic BCBM, whole-brain radiotherapy (WBRT), if possible with hippocampal sparing, is recommended. In cases of multiple asymptomatic BCBM (≥ 5), if SRS/SRT is not feasible or in disseminated brain metastases (> 10), postponing WBRT with early reassessment and reevaluation of local treatment options (8-12 weeks) may be discussed if a HER2/Neu-targeting systemic therapy with significant response rates in the central nervous system (CNS) is being used. In symptomatic leptomeningeal carcinomatosis, local radiotherapy (WBRT or local spinal irradiation) should be performed in addition to systemic therapy. In patients with disseminated leptomeningeal carcinomatosis in good clinical condition and with only limited or stable extra-CNS disease, craniospinal irradiation (CSI) may be considered. Data regarding the toxicity of combining systemic therapies with cranial and spinal radiotherapy are sparse. Therefore, no clear recommendations can be given, and each case should be discussed individually in an interdisciplinary setting.

Oligometastasis in breast cancer-current status and treatment options from a radiation oncology perspective.

Evidence from a few small randomized trials and retrospective cohorts mostly including various tumor entities indicates a prolongation of disease free survival (DFS) and overall survival (OS) from local ablative therapies in oligometastatic disease (OMD). However, it is still unclear which patients benefit most from this approach. We give an overview of the several aspects of stereotactic body radiotherapy (SBRT) in extracranial OMD in breast cancer from a radiation oncology perspective. A PubMed search referring to this was conducted. An attempt was made to relate the therapeutic efficacy of SBRT to various prognostic factors. Data from approximately 500 breast cancer patients treated with SBRT for OMD in mostly in small cohort studies have been published, consistently indicating high local tumor control rates and favorable progression-free (PFS) and overall survival (OS). Predictors for a good prognosis after SBRT are favorable biological subtype (hormone receptor positive, HER2 negative), solitary metastasis, bone-only metastasis, and long metastasis-free interval. However, definitive proof that SBRT in OMD breast cancer prolongs DFS or OS is lacking, since, with the exception of one small randomized trial (n = 22 in the SBRT arm), none of the cohort studies had an adequate control group. Further studies are needed to prove the benefit of SBRT in OMD breast cancer and to define adequate selection criteria. Currently, the use of local ablative SBRT should always be discussed in a multidisciplinary tumor board.

Post-neoadjuvant treatment with capecitabine and trastuzumab emtansine in breast cancer patients-sequentially, or better simultaneously?

PURPOSE: Following neoadjuvant chemotherapy for breast cancer, postoperative systemic therapy, also called post-neoadjuvant treatment, has been established in defined risk settings. We reviewed the evidence for sequencing of postoperative radiation and chemotherapy, with a focus on a capecitabine and trastuzumab emtansine (T-DM1)-based regimen. METHODS: A systematic literature search using the PubMed/MEDLINE/Web of Science database was performed. We included prospective and retrospective reports published since 2015 and provided clinical data on toxicity and effectiveness. RESULTS: Six studies were included, five of which investigated capecitabine-containing regimens. Of these, four were prospective investigations and one a retrospective matched comparative analysis. One randomized prospective trial was found for T­DM1 and radiotherapy. In the majority of these reports, radiation-associated toxicities were not specifically addressed. CONCLUSION: Regarding oncologic outcome, the influence of sequencing radiation therapy with maintenance capecitabine chemotherapy in the post-neoadjuvant setting is unclear. Synchronous administration of capecitabine is feasible, but reports on possible excess toxicities are partially conflicting. Dose reduction of capecitabine should be considered, especially if normofractionated radiotherapy is used. In terms of tolerance, hypofractionated schedules seem to be superior in terms of toxicity in concurrent settings. T­DM1 can safely be administered concurrently with radiotherapy.

Moderate hypofractionation remains the standard of care for whole-breast radiotherapy in breast cancer: Considerations regarding FAST and FAST-Forward.

Moderate hypofractionation is the standard of care for adjuvant whole-breast radiotherapy after breast-conserving surgery for breast cancer. Recently, 10-year results from the FAST and 5­year results from the FAST-Forward trial evaluating adjuvant whole-breast radiotherapy in 5 fractions over 5 weeks or 1 week have been published. This article summarizes recent data for moderate hypofractionation and results from the FAST and FAST-Forward trial on ultra-hypofractionation. While the FAST trial was not powered for comparison of local recurrence rates, FAST-Forward demonstrated non-inferiority for two ultra-hypofractionated regimens in terms of local control. In both trials, the higher-dose experimental arms resulted in elevated rates of late toxicity. For the lower dose experimental arms of 28.5 Gy over 5 weeks and 26 Gy over 1 week, moderate or marked late effects were similar in the majority of documented items compared to the respective standard arms, but significantly worse in some subdomains. The difference between the standard arm and the 26 Gy of the FAST-Forward trial concerning moderate or marked late effects increased with longer follow-up in disadvantage of the experimental arm for most items. For now, moderate hypofractionation with 40-42.5 Gy over 15-16 fractions remains the standard of care for the majority of patients with breast cancer who undergo whole-breast radiotherapy without regional nodal irradiation after breast-conserving surgery.

Heart-sparing radiotherapy techniques in breast cancer patients: a recommendation of the breast cancer expert panel of the German society of radiation oncology (DEGRO).

PURPOSE: The aim of this review was to analyze the respective efficacy of various heart-sparing radiotherapy techniques. MATERIAL AND METHODS: Heart-sparing can be performed in three different ways in breast cancer radiotherapy: by seeking to keep the heart out of treated volumes (i.e. by prone position or specific breathing techniques such as deep inspiration breath-hold [DIBH] and/or gating), by solely irradiating a small volume around the lumpectomy cavity (partial breast irradiation, PBI), or by using modern radiation techniques like intensity-modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT) or protons. This overview presents the available data on these three approaches. RESULTS: Studies on prone position are heterogeneous and most trials only refer to patients with large breasts; therefore, no definitive conclusion can be drawn for clinical routine. Nonetheless, there seems to be a trend toward better sparing of the left anterior descending artery in supine position even for these selected patients. The data on the use of DIBH for heart-sparing in breast cancer patients is consistent and the benefit compared to free-breathing is supported by several studies. In comparison with whole breast irradiation (WBI), PBI has an advantage in reducing the heart dose. Of note, DIBH and PBI with multicatheter brachytherapy are similar with regard to the dose reduction to heart structures. WBI by IMRT/VMAT techniques without DIBH is not an effective strategy for heart-sparing in breast cancer patients with "standard" anatomy. A combination of DIBH and IMRT may be used for internal mammary radiotherapy. CONCLUSION: Based on the available findings, the DEGRO breast cancer expert panel recommends the use of DIBH as the best heart-sparing technique. Nonetheless, depending on the treatment volume and localization, other techniques may be employed or combined with DIBH when appropriate.

Heart toxicity from breast cancer radiotherapy : Current findings, assessment, and prevention.

BACKGROUND: Late cardiac toxicities caused by (particularly left-sided) breast radiotherapy (RT) are now recognized as rare but relevant sequelae, which has prompted research on risk structure identification and definition of threshold doses to heart subvolumes. The aim of the present review was to critically discuss the clinical evidence on late cardiac reactions based on dose-dependent outcome reports for mean heart doses as well as doses to cardiac substructures. METHODS: A literature review was performed to examine clinical evidence on radiation-induced heart toxicities. Mean heart doses and doses to cardiac substructures were focused upon based on dose-dependent outcome reports. Furthermore, an overview of radiation techniques for heart protection is given and non-radiotherapeutic aspects of cardiotoxicity in the multimodal setting of breast cancer treatment are discussed. RESULTS: Based on available findings, the DEGRO breast cancer expert panel recommends the following constraints: mean heart dose <2.5 Gy; DmeanLV (mean dose left ventricle) < 3 Gy; V5LV (volume of LV receiving ≥5 Gy) < 17%; V23LV (volume of LV receiving ≥23 Gy) < 5%; DmeanLAD (mean dose left descending artery) < 10 Gy; V30LAD (volume of LAD receiving ≥30 Gy) < 2%; V40LAD (volume of LAD receiving ≥40 Gy) < 1%. CONCLUSION: In addition to mean heart dose, breast cancer RT treatment planning should also include constraints for cardiac subvolumes such as LV and LAD. The given constraints serve as a clinicians' aid for ensuring adequate heart protection. The individual decision between sufficient protection of cardiac structures versus optimal target volume coverage remains in the physician's hand. The risk of breast cancer-specific mortality and a patient's cardiac risk factors must be individually weighed up against the risk of radiation-induced cardiotoxicity.

Radiotherapy after skin-sparing mastectomy with immediate breast reconstruction in intermediate-risk breast cancer : Indication and technical considerations.

BACKGROUND: Skin-sparing (SSME) and nipple-sparing mastectomy (NSME) were developed to improve the cosmetic results for breast cancer (BC) patients, both allowing for immediate breast reconstruction. Recommendations for post-mastectomy radiotherapy (PMRT) are primarily derived from trials where patients were treated by standard mastectomies. Due to their more conservative character, SSME and especially NSME potentially leave more glandular tissue at risk for subclinical disease. METHODS: Rates and sites of locoregional failures following SSME and NSME plus/minus reconstruction were analyzed regarding tumor stage and biological risk factors. In particular, the role of PMRT in "intermediate"-risk and early stage high-risk breast cancer patients was revisited. Implications on targeting and dose delivery of PMRT were critically reviewed. RESULTS: The value of PMRT in stage III BC remains undisputed. For node-negative BC patients, the majority of reports classify clinical and biological features such as tumor size, close surgical margins, premenopausal status, multicentricity, lymphangiosis, triple-negativity, HER2-overexpression, and poor tumor grading as associated with higher rates of locoregional relapse, thus, building an "intermediate" risk group. Surveys revealed that the majority of radiation oncologists use risk-adaptive models also considering the number of coinciding factors for the estimation of recurrence probability following SSME and NSME. Constellations with a 10-year locoregional recurrence risk of >10% are usually triggering the indication for PMRT. There was no common belief that the amount of residual tissue, e.g., tissue thickness over flaps, serves as additional decision aid. Modern treatment planning can ensure optimal dose distribution for PMRT in almost all patients with SSME. There are no reliable data supporting a reduction of the treatment volume from the CTV chest wall, e.g., to the nipple-areola complex, to the dorsal aspect behind the implant volume, the pectoralis muscle, nor the regional interpectoral, axillary, or complete regional lymph nodes only. The omission of a skin bolus in intermediate-risk BC does not compromise oncological safety. CONCLUSIONS: For intermediate-risk as well as early stage high-risk BC patients, the DEGRO Breast Cancer Expert Panel recommends the use of PMRT following SSME and NSME when a 10-year locoregional recurrence risk is likely to be greater than 10%, as estimated by clinical and biological risk factors. Subvolume-only radiation is discouraged outside of trials. The impact of adequate systemic treatment and the value of radiotherapy on optimal locoregional tumor control, with the goal of less than 5% LRR at 10-years follow-up, has to be verified in prospective trials.

Individualization of post-mastectomy radiotherapy and regional nodal irradiation based on treatment response after neoadjuvant chemotherapy for breast cancer : A systematic review.

PURPOSE: To review the evidence regarding post-mastectomy radiotherapy (PMRT) and regional nodal irradiation (RNI) after neoadjuvant chemotherapy (NACT) for breast cancer, with a special focus on individualization of adjuvant radiotherapy based on treatment response. METHODS: A systematic literature search using the PubMed/Medline database was performed. We included prospective and retrospective reports with a minimum of 10 patients that had been published since 1st January 2000, and provided clinical outcome data analyzed by treatment response and radiotherapy. RESULTS: Out of 763 articles identified via PubMed/Medline and hand search, 68 full text-articles were assessed for eligibility after screening of title and abstract. 13 studies were included in the systematic review, 9 for PMRT and 5 for RNI. All included studies were retrospective reports. CONCLUSIONS: There is a considerable lack of evidence regarding the role of adjuvant radiotherapy and its individualization based on treatment response after NACT. Results of prospective randomized trials such as NSABP B­51/RTOG 1304 and Alliance A11202 are eagerly awaited.

Neoadjuvant chemotherapy for breast cancer-background for the indication of locoregional treatment.

Neoadjuvant chemotherapy (NACT) has been widely adopted into the multidisciplinary management of breast cancer. The prognostic impact of treatment response has been clearly demonstrated. However, the impact of treatment response on the indication for adjuvant radiotherapy is unclear. This review summarizes important implications of NACT and treatment response on the risk of recurrence and locoregional multidisciplinary management from the standpoint of radiation oncology.

DEGRO practical guidelines for radiotherapy of breast cancer V: Therapy for locally advanced and inflammatory breast cancer, as well as local therapy in cases with synchronous distant metastases.

AIM: The purpose of this work is to give practical guidelines for radiotherapy of locally advanced, inflammatory and metastatic breast cancer at first presentation. METHODS: A comprehensive survey of the literature using the search phrases "locally advanced breast cancer", "inflammatory breast cancer", "breast cancer and synchronous metastases", "de novo stage IV and breast cancer", and "metastatic breast cancer" and "at first presentation" restricted to "clinical trials", "randomized trials", "meta-analysis", "systematic review", and "guideline" was performed and supplemented by using references of the respective publications. Based on the German interdisciplinary S3 guidelines, updated in 2012, this publication addresses indications, sequence to other therapies, target volumes, dose, and fractionation of radiotherapy. RESULTS: International and national guidelines are in agreement that locally advanced, at least if regarded primarily unresectable and inflammatory breast cancer should receive neoadjuvant systemic therapy first, followed by surgery and radiotherapy. If surgery is not amenable after systemic therapy, radiotherapy is the treatment of choice followed by surgery, if possible. Surgery and radiotherapy should be administered independent of response to neoadjuvant systemic treatment. In patients with a de novo diagnosis of breast cancer with synchronous distant metastases, surgery and radiotherapy result in considerably better locoregional tumor control. An improvement in survival has not been consistently proven, but may exist in subgroups of patients. CONCLUSION: Radiotherapy is an important part in the treatment of locally advanced and inflammatory breast cancer that should be given to all patients regardless to the intensity and effect of neoadjuvant systemic treatment and the extent of surgery. Locoregional radiotherapy in patients with primarily distant metastatic disease should be prescribed on an individual basis.

DEGRO practical guidelines for radiotherapy of breast cancer IV: radiotherapy following mastectomy for invasive breast cancer.

BACKGROUND AND PURPOSE: Since the last recommendations from the Breast Cancer Expert Panel of the German Society for Radiation Oncology (DEGRO) in 2008, evidence for the effectiveness of postmastectomy radiotherapy (PMRT) has grown. This growth is based on updates of the national S3 and international guidelines, as well as on new data and meta-analyses. New aspects were considered when updating the DEGRO recommendations. METHODS: The authors performed a comprehensive survey of the literature. Data from recently published (meta-)analyses, randomized clinical trials and international cancer societies' guidelines yielding new aspects compared to 2008 were reviewed and discussed. New aspects were included in the current guidelines. Specific issues relating to particular PMRT constellations, such as the presence of risk factors (lymphovascular invasion, blood vessel invasion, positive lymph node ratio >20 %, resection margins <3 mm, G3 grading, young age/premenopausal status, extracapsular invasion, negative hormone receptor status, invasive lobular cancer, size >2 cm or a combination of ≥ 2 risk factors) and 1-3 positive lymph nodes are emphasized. RESULTS: The evidence for improved overall survival and local control following PMRT for T4 tumors, positive resection margins, >3 positive lymph nodes and in T3 N0 patients with risk factors such as lymphovascular invasion, G3 grading, close margins, and young age has increased. Recently identified risk factors such as invasive lobular subtype and negative hormone receptor status were included. For patients with 1-3 positive lymph nodes, the recommendation for PMRT has reached the 1a level of evidence. CONCLUSION: PMRT is mandatory in patients with T4 tumors and/or positive lymph nodes and/or positive resection margins. PMRT should be strongly considered in patients with T3 N0 tumors and risk factors, particularly when two or more risk factors are present.

Long-Term Results of the TARGIT-A Trial: More Questions than Answers.

Background: During the last decade, partial breast irradiation (PBI) has gained traction as a relevant treatment option for patients with early-stage low-risk breast cancer after breast-conserving surgery. The TARGIT-A prospective randomized trial compared a "risk-adapted" intraoperative radiotherapy (IORT) approach with 50-kv X-rays (INTRABEAM®) as the PBI followed by optional whole-breast irradiation (WBI) and conventional adjuvant WBI in terms of observed 5-year in-breast recurrence rates. Recently, long-term data were published. Since the first publication of the TARGIT-A trial, a broad debate has been emerged regarding several uncertainties and limitations associated with data analysis and interpretation. Our main objective was to summarize the data, with an emphasis on the updated report and the resulting implications. Summary: From our point of view, the previously unresolved questions still remain and more have been added, especially with regard to the study design, a change in the primary outcome measure, the significant number of patients lost to follow-up, and the lack of a subgroup analysis according to risk factors and treatment specifications. Key Message: Taking into account the abovementioned limitations of the recently published long-term results of the TARGIT-A trial, the German Society of Radiation Oncology (DEGRO) Breast Cancer Expert Panel adheres to its recently published recommendations on PBI: "the 50-kV system (INTRABEAM) cannot be recommended for routine adjuvant PBI treatment after breast-conserving surgery."

Intraoperative radiotherapy as accelerated partial breast irradiation for early breast cancer : beware of one-stop shops?

Intraoperative radiotherapy (IORT) was originally introduced in breast cancer treatment as an "anticipated boost" during the procedure of breast conserving surgery (BCS). In addition to whole breast irradiation (WBI), it has yielded excellent long-term results [31, 38]. Under the assumption that the majority of in-breast tumor recurrences (IBTR) occur in the originally affected site, accelerated partial breast irradiation (APBI) as the sole treatment modality was initiated in several studies and with different techniques, one of which was IORT first with electrons, later also with conventional x-rays [29]. The question whether and for whom the gold standard of WBI may be replaced by APBI - especially IORT - alone has recently been one of the most controversial issues of adjuvant therapy for breast cancer. Two recently published studies by Veronesi et al. [36] and Vaidya et al. [35] presenting shortterm results of single shot IORT with electrons (ELIOT) and with an orthovoltage system (TARGIT), respectively, have further invigorated this discussion as illustrated by several letters to the editor commenting on the TARGIT study. While Vaidya et al. [35] indicate their results of IORT alone as "an alternative to WBI for selected patients" and one editorial even proclaims it as standard [6], all the authors of the respective letters [10, 16, 27, 33] strongly disagree with this conclusion. The present editorial comments on the two publications and, furthermore, provides respective statements of the breast cancer expert panel of the German Society of Radiation Oncology (DEGRO).

DEGRO Practical Guidelines for palliative radiotherapy of breast cancer patients: brain metastases and leptomeningeal carcinomatosis.

PURPOSE: To provide recommendations for palliative treatment of brain metastases (BM) and leptomeningeal carcinomatosis (LC) in breast cancer patients with specific emphasis on radiooncologic aspects. METHODS: The breast cancer expert panel of the German Society of Radiation Oncology (DEGRO) performed a comprehensive survey of the literature comprising national and international guidelines, lately published randomized trials, and relevant retrospective analyses. The search included publications between 1995-2008 (PubMed and Guidelines International Network [G-I-N]). Recommendations were devised according to the panel's interpretation of the evidence referring to the criteria of EBM. RESULTS: Aim of any treatment of BM and LC is to alleviate symptoms and improve neurologic deficits. Close interdisciplinary cooperation facilitates rapid diagnosis and onset of therapy, tailored to the individual and clinical situation. Treatment decisions for BM should be based on the allocation to three prognostic groups defined by recursive partitioning analysis (RPA). Karnofsky Performance Score (KPS) is the strongest prognostic parameter. Together with the extent of the disease, KPS determines whether excision or radiosurgery/stereotactic radiotherapy is feasible and if exclusive or additional whole-brain radiotherapy (WBRT) is indicated. With adequate therapy, survival may be up to 3 years. For LC, treatment is mostly indicated for patients with positive cytology or in case of strongly indicative signs and symptoms. Radiotherapy (WBRT and involved-field irradiation of bulky spinal lesions) and chemotherapy (systemically or intrathecally applied methotrexate, thiotepa and cytarabine) are both effective and may prolong survival from several weeks to 4-6 months. CONCLUSION: Radiotherapy is an effective tool for palliative treatment of BM and LC.

Commercially Available Gene Expression Assays as Predictive Tools for Adjuvant Radiotherapy? A Critical Review.

BACKGROUND: Gene expression assays are increasingly used for decision-making regarding adjuvant chemotherapy in patients with hormone receptor-positive, HER2-negative breast cancer. There are some clinical situations in which there is also a need for better prognostic and predictive markers to better estimate the amount of benefit from adjuvant radiotherapy. The rising availability of gene expression analyses prompts the question whether their results can also be used to guide clinical decisions regarding adjuvant radiation. SUMMARY: Multiple studies suggest a correlation between results from gene expression assays and locoregional recurrence rates. Only few publications addressed the predictive value of results from gene expression analysis for the role of adjuvant radiotherapy in different settings. KEY MESSAGES: To date, the available evidence on the possible predictive value of gene expression assays for radiotherapy does not support their inclusion into the decision-making process for adjuvant radiation. This is due to methodological weaknesses and limitations regarding patient selection, the nonrandomized design of all studies in terms of radiotherapy use, and limited availability of tissue from prospective trials. Thus, utilization of the present knowledge for clinical indication of radiotherapy should be very cautious.

DEGRO practice guidelines for palliative radiotherapy of metastatic breast cancer: bone metastases and metastatic spinal cord compression (MSCC).

PURPOSE: To provide practice guidelines and clinical recommendations on preferred standard palliative radiation therapy of bone metastases as well as metastatic spinal cord compression (MSCC) for metastatic breast cancer patients. METHODS: The breast cancer expert panel of the German Society of Radiation Oncology (DEGRO) performed a comprehensive survey of the literature comprising recently published data from clinical controlled trials. The literature search encompassed the period 1995-2008 using databases of PubMed and Guidelines International Network (G-I-N). Search terms were "breast cancer", "bone metastasis", "osseous metastasis", "metastatic spinal cord compression" as well as "radiotherapy" and "radiation therapy". Clinical recommendations were formulated based on the panel's interpretation of the level of evidence referring to the criteria of evidence-based medicine. RESULTS: Different therapeutic goals (pain relief, local tumor control, prevention or improvement of motor deficits, stabilization of the spine or other bones) require complex approaches considering individual factors (i.e., life expectancy, tumor progression at other sites). Best results are achieved by close interdisciplinary cooperation minimizing the interval between diagnosis and onset of treatment. Most important criteria for prognosis and choice of treatment (mostly combined multimodal therapy) are neurologic status at diagnosis of MSCC, time course of duration and progression of the neurologic symptoms. Radiation therapy is effective and regarded as treatment of choice for MSCC with or without motor deficits and/or bone metastases, which do not need immediate surgical intervention. It may be used either postoperatively or as primary treatment in case of inoperability. An optimal dose fractionation schedule or optimal standard dose for treatment of bone metastases has not been established. With regard to different therapeutic goals, different dose concepts and fractionation schedules, single- versus multifraction palliative radiation therapy (1 x 8, 5 x 4, 10 x 3, 15 x 2.5, 20 x 2 Gy), should be adapted individually. CONCLUSION: Bone metastases as well as MSCC should be managed in an interdisciplinary approach mostly as combined-modality treatment according to the specific clinical situation. The present practice guidelines offer criteria and recommendations for different radiooncologic treatment schedules based on the best available levels of evidence. Preferred technique, targeting and different dose schedules are described in detail.

Genetic predictors of long-term toxicities after radiation therapy for breast cancer.

Telangiectasia and subcutaneous fibrosis are the most common late dermatologic side effects observed in response to radiation treatment. Radiotherapy acts on cancer cells largely due to the generation of reactive oxygen species (ROS). ROS also induce normal tissue toxicities. Therefore, we investigated if genetic variation in oxidative stress-related enzymes confers increased susceptibility to late skin complications. Women who received radiotherapy following lumpectomy for breast cancer were followed prospectively for late tissue side effects after initial treatment. Final analysis included 390 patients. Polymorphisms in genes involved in oxidative stress-related mechanisms (GSTA1, GSTM1, GSTT1, GSTP1, MPO, MnSOD, eNOS, CAT) were determined from blood samples by MALDI-TOF. The associations between telangiectasia and genotypes were evaluated by multivariate unconditional logistic regression models. Patients with variant GSTA1 genotypes were at significantly increased risk of telangiectasia (OR 1.86, 95% CI 1.11-3.11). Reduced odds ratios of telangiectasia were noted for women with lower-activity eNOS genotype (OR 0.58, 95% CI 0.36-0.93). Genotype effects were modified by follow-up time, with the highest risk observed after 4 years of radiotherapy for gene polymorphisms in ROS-neutralizing enzymes. Decreased risk with eNOS polymorphisms was significant only among women with less than 4 years of follow-up. All other risk estimates were nonsignificant. Late effects of radiation therapy on skin appear to be modified by variants in genes related to protection from oxidative stress. The application of genomics to outcomes following radiation therapy holds the promise of radiation dose adjustment to improve both cosmetic outcomes and quality of life for breast cancer patients.

Polymorphisms in genes related to oxidative stress (CAT, MnSOD, MPO, and eNOS) and acute toxicities from radiation therapy following lumpectomy for breast cancer.

PURPOSE: Because radiotherapy exerts cytotoxic effects via generation of massive oxidative stress, we hypothesized that catalase, manganese superoxide dismutase, myeloperoxidase (MPO), and endothelial nitric oxide synthase (eNOS) genotypes might result in greater risk of radiotoxicity. EXPERIMENTAL DESIGN: Cases (n = 446) were Caucasian women with breast cancer who received radiotherapy following lumpectomy. Genotypes were determined by matrix-assisted laser desorption/ionization time-of-flight. The development of acute reactions (moist desquamation) associated with genotypes was modeled using the Cox proportional hazards model, accounting for cumulative biologically effective radiation dose. RESULTS: Genotypes associated with higher levels of reactive oxygen species (ROS) were not associated with risk of radiotoxicity. However, relationships between overweight/obesity [body mass index (BMI), >25] and radiotoxicity risk seemed to be modified by eNOS and MPO genotypes associated with higher generation of nitric oxide and ROS, respectively. Women with high BMI (>25) and eNOS GG genotypes were at more than a 6-fold increase in risk (hazard ratio, 6.39; 95% confidence interval, 2.53-16.15) compared with those with BMI <25, and for MPO, those with high BMI (>25) and GG genotypes also had greater risk of radiotoxicity (hazard ratio, 3.61; 95% confidence interval, 1.78-7.35) compared with those with BMI <25. Overweight/obesity was not a strong risk factor among women with other eNOS and MPO genotypes. Exploratory analysis using classification and regression trees indicated that total number of risk alleles contributed, in part, to acute toxicity outcomes among a subgroup of women. CONCLUSIONS: Associations between BMI and radiotoxicity risk may be most apparent among women with genotypes related to higher levels of oxidative stress. Regression trees may be useful in future studies to examine the contributions of multiple factors to individual susceptibility to adverse effects of cancer treatment.

Current controversies in radiotherapy for breast cancer.

Multimodal treatment approaches have substantially improved the outcome of breast cancer patients in the last decades. Radiotherapy is an integral component of multimodal treatment concepts used in curative and palliative intention in numerous clinical situations from precursor lesions such as ductal carcinoma in situ (DCIS) to advanced breast cancer. This review addresses current controversial topics in radiotherapy with special consideration of DCIS, accelerated partial breast irradiation (APBI) and regional nodal irradiation (RNI) and provides an update on the clinical practice guidelines of the Breast Cancer Expert Panel of the German Society of Radiation Oncology (DEGRO).

Genetic predictors of acute toxicities related to radiation therapy following lumpectomy for breast cancer: a case-series study.

INTRODUCTION: The cytotoxic effects of radiation therapy are mediated primarily through increased formation of hydroxyl radicals and reactive oxygen species, which can damage cells, proteins and DNA; the glutathione S-transferases (GSTs) function to protect against oxidative stress. We hypothesized that polymorphisms encoding reduced or absent activity in the GSTs might result in greater risk for radiation-associated toxicity. METHODS: Women receiving therapy in radiation units in Germany following lumpectomy for breast cancer (1998-2001) provided a blood sample and completed an epidemiological questionnaire (n = 446). Genotypes were determined using Sequonom MALDI-TOF (GSTA1, GSTP1) and Masscode (GSTM1, GSTT1). Biologically effective radiotherapy dose (BED) was calculated, accounting for differences in fractionation and overall treatment time. Side effects considered were grade 2c and above, as classified using the modified Common Toxicity Criteria. Predictors of toxicity were modelled using Cox regression models in relation to BED, with adjustment for treating clinic, photon field, beam energy and boost method, and potential confounding variables. RESULTS: Low activity GSTP1 genotypes were associated with a greater than twofold increase in risk for acute skin toxicities (adjusted hazard ratio 2.28, 95% confidence interval 1.04-4.99). No associations were noted for the other GST genotypes. CONCLUSION: These data indicate that GSTP1 plays an important role in protecting normal cells from damage associated with radiation therapy. Studies examining the effects of GSTP1 polymorphisms on toxicity, recurrence and survival will further inform individualized therapeutics based on genotypes.