Interobserver variability (between radiation oncologist and radiation therapist) in tumor bed contouring after breast-conserving surgery

PURPOSE

To examine interobserver variability between the radiation oncologist (RTO) and the radiation therapist (RTT) in delineating the tumor bed (TB) in early breast cancer (BC).

METHODS

We retrospectively analyzed patients who received a radiotherapy boost to the TB. In a first group, the clinical target volume (CTV) for the boost was the surgical bed, defined by using surgical clips. In a second group, the CTV was defined by identifying a seroma cavity or a metallic find on the scar. These contours were compared in terms of volume, number of slices, and Dice similarity coefficient (DSC).

RESULTS

Forty patients were assessed: 20 had surgical clips (group 1) while the other 20 had none (group 2). There was no difference in the number of slices contoured by the 2 operators for group 1, but a statistically significant difference emerged in the volumes: the RTT identified a TB that was a mean 45% smaller than the one identified by the RTO. Random differences were found between the 2 operators for group 2. The TBs delineated for this group were significantly larger (P<0.05) than those identified by the RTT for group 1. The mean Dice value between the RTO's and the RTT's TBs was 0.69±0.07 (range 0.53-0.81) for group 1 and 0.37±0.18 (range 0-0.58) for group 2 (P<0.05).

CONCLUSIONS

This study showed that the use of clips coincided with less interoperator variability. With appropriate training, the RTT may play an important part in the multidisciplinary radiotherapy team.

Human Anti-fungal Th17 Immunity and Pathology Rely on Cross-Reactivity against Candida albicans

Th17 cells provide protection at barrier tissues but may also contribute to immune pathology. The relevance and induction mechanisms of pathologic Th17 responses in humans are poorly understood. Here, we identify the mucocutaneous pathobiont Candida albicans as the major direct inducer of human anti-fungal Th17 cells. Th17 cells directed against other fungi are induced by cross-reactivity to C. albicans. Intestinal inflammation expands total C. albicans and cross-reactive Th17 cells. Strikingly, Th17 cells cross-reactive to the airborne fungus Aspergillus fumigatus are selectively activated and expanded in patients with airway inflammation, especially during acute allergic bronchopulmonary aspergillosis. This indicates a direct link between protective intestinal Th17 responses against C. albicans and lung inflammation caused by airborne fungi. We identify heterologous immunity to a single, ubiquitous member of the microbiota as a central mechanism for systemic induction of human anti-fungal Th17 responses and as a potential risk factor for pulmonary inflammatory diseases.

Humanized Mouse Model Mimicking Pathology of Human Tuberculosis for in vivo Evaluation of Drug Regimens

Human immune system mice are highly valuable for in vivo dissection of human immune responses. Although they were employed for analyzing tuberculosis (TB) disease, there is little data on the spatial organization and cellular composition of human immune cells in TB granuloma pathology in this model. We demonstrate that human immune system mice, generated by transplanted human fetal liver derived hematopoietic stem cells develop a continuum of pulmonary lesions upon Mycobacterium tuberculosis aerosol infection. In particular, caseous necrotic granulomas, which contribute to prolonged TB treatment time, developed, and had cellular phenotypic spatial-organization similar to TB patients. By comparing two recommended drug regimens, we confirmed observations made in clinical settings: Adding Moxifloxacin to a classical chemotherapy regimen had no beneficial effects on bacterial eradication. We consider this model instrumental for deeper understanding of human specific features of TB pathogenesis and of particular value for the pre-clinical drug development pipeline.

Radiotherapy with the anti-programmed cell death ligand-1 immune checkpoint blocker avelumab: acute toxicities in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is clinically the most aggressive breast cancer (BC) subtype. There is an urgent need for effective therapies for patients with TNBC. Recent findings confirm the important role of factors related to the immune system in the clinical outcome and response to treatment of TNBC patients. Avelumab selectively binds to PDL1, and competitively blocks its interaction with anti-programmed death 1 (anti-PD-1) antibodies. Unlike anti-PD-1 antibodies, which target T-cells, avelumab targets tumor cells, and is therefore expected to have fewer side effects, including a lower risk of Immune-Related Adverse Events (irAEs). Uncertainties remain regarding a potential synergy resulting in increased toxicities by combining radiotherapy and immune-checkpoint inhibitors (ICIs). Effects of concomitant ICIs with thoracic radiotherapy on pulmonary toxicities is not currently known. There are no published data available on the effects of combining anti-PD-L1 with adjuvant radiotherapy (RT) for BC in a clinical setting. We reported a preliminary experience on the first patient treated at the National Cancer Institute of Milan with the association of avelumab and concomitantly RT for TNBC.

Human Monocytic Suppressive Cells Promote Replication of Mycobacterium tuberculosis and Alter Stability of in vitro Generated Granulomas

Tuberculosis (TB) has tremendous public health relevance. It most frequently affects the lung and is characterized by the development of unique tissue lesions, termed granulomas. These lesions encompass various immune populations, with macrophages being most extensively investigated. Myeloid derived suppressor cells (MDSCs) have been recently identified in TB patients, both in the circulation and at the site of infection, however their interactions with Mycobacterium tuberculosis (Mtb) and their impact on granulomas remain undefined. We generated human monocytic MDSCs and observed that their suppressive capacities are retained upon Mtb infection. We employed an in vitro granuloma model, which mimics human TB lesions to some extent, with the aim of analyzing the roles of MDSCs within granulomas. MDSCs altered the structure of and affected bacterial containment within granuloma-like structures. These effects were partly controlled through highly abundant secreted IL-10. Compared to macrophages, MDSCs activated primarily the NF-κB and MAPK pathways and the latter largely contributed to the release of IL-10 and replication of bacteria within in vitro generated granulomas. Moreover, MDSCs upregulated PD-L1 and suppressed proliferation of lymphocytes, albeit with negligible effects on Mtb replication. Further comprehensive characterization of MDSCs in TB will contribute to a better understanding of disease pathogenesis and facilitate the design of novel immune-based interventions for this deadly infection.

Discontinuation of hormone therapy for elderly breast cancer patients after hypofractionated whole-breast radiotherapy

The purpose of the study was to examine adherence to hormone therapy (HT) in elderly breast cancer patients (≥ 65 years old) treated with hypofractionated radiotherapy. We analyzed data on 550 ER-positive breast cancer patients given hypofractionated whole-breast radiotherapy from June 2009 to September 2016. Baseline comorbidities considered in the hypertension-augmented Charlson Comorbidity Index (hCCI) were retrospectively retrieved. Total hCCI scores were classified as no comorbidity (hCCI = 0), low burden of comorbidity (hCCI = 1), and high burden of comorbidity (hCCI ≥ 2). Competing risk analysis was used to estimate the 5-year cumulative incidence of HT discontinuation. Fine and Gray models were used to estimate the adjusted subhazard ratio (SHR) of HT discontinuation by hCCI score. HT was initially prescribed for 85.6% of patients and almost all of them (468/471) took it for at least one month. It was subsequently discontinued by 45 patients (9.6%), for an overall 5-year cumulative incidence of 11.7%. The 5-year cumulative incidence of HT discontinuation rose from 3.9% in the youngest age group (65-69 years) to 23.3% in the oldest (≥ 80 years) (p = 0.005). Baseline comorbidity had some effect on the likelihood of discontinuing HT, but only among patients with a low burden of comorbidity (hCCI = 1, SHR 2.00, 95%CI 0.95-4.20). Adherence to HT was better in our sample than in the literature, probably because patients were selected and motivated to continue HT. This confirms the importance of communication with patients to improve adherence to HT. We confirmed the association between HT discontinuation and older age, while comorbidity had a limited influence.

Mycobacterium tuberculosis Invasion of the Human Lung: First Contact

Early immune responses to Mycobacterium tuberculosis (Mtb) invasion of the human lung play a decisive role in the outcome of infection, leading to either rapid clearance of the pathogen or stable infection. Despite their critical impact on health and disease, these early host-pathogen interactions at the primary site of infection are still poorly understood. In vitro studies cannot fully reflect the complexity of the lung architecture and its impact on host-pathogen interactions, while animal models have their own limitations. In this study, we have investigated the initial responses in human lung tissue explants to Mtb infection, focusing primarily on gene expression patterns in different tissue-resident cell types. As first cell types confronted with pathogens invading the lung, alveolar macrophages, and epithelial cells displayed rapid proinflammatory chemokine and cytokine responses to Mtb infection. Other tissue-resident innate cells like gamma/delta T cells, mucosal associated invariant T cells, and natural killer cells showed partially similar but weaker responses, with a high degree of variability across different donors. Finally, we investigated the responses of tissue-resident innate lymphoid cells to the inflammatory milieu induced by Mtb infection. Our infection model provides a unique approach toward host-pathogen interactions at the natural port of Mtb entry and site of its implantation, i.e., the human lung. Our data provide a first detailed insight into the early responses of different relevant pulmonary cells in the alveolar microenvironment to contact with Mtb. These results can form the basis for the identification of host markers that orchestrate early host defense and provide resistance or susceptibility to stable Mtb infection.

Radio-Chemotherapy of Anal Cancer

Conventional treatment of anal cancer has been the demolitive Miles operation for decades. Radiotherapy has been utilized in a limited number of centers for early cancers only. Radio-chemotherapy has become the treatment of choice for all stages of anal cancer after the first experiences by the group of Detroit and after the confirmation of successful results by many other centers. Infusional chemotherapy (5-FU and Mitomycin C or CDDP) and concurrent irradiation are able to achieve local control in more than 80% of patients. Surgery currently represents a rescue treatment for partial responders or in relapsing patients. A brief review of the literature and the experience at the Istituto Tumori in Milano are presented.

Hypofractionated Whole-Breast Irradiation With or Without Boost in Elderly Patients: Clinical Evaluation of an Italian Experience

PURPOSE

To examine local control, disease-free survival (DFS), and toxicity in elderly (≥ 65 years) breast cancer patients treated with hypofractionated radiotherapy (hypo-RT) with or without a boost to the tumor bed.

PATIENTS AND METHODS

The study was conducted on 752 patients treated from April 2009 to February 2017. Patients received 42.4 Gy in 16 daily fractions (2.65 Gy per fraction). A boost was only administered in cases of grade 3 primary tumor and close or positive margins. Acute and late toxicity was prospectively assessed during and after hypo-RT, based on the Radiation Therapy Oncology Group scale. DFS and local recurrence-free survival were estimated by the Kaplan-Meier method for cumulative probability. Log-rank tests were used to identify differences by subtype. Cox proportional hazard models were used to investigate the impact of various factors on the risk of disease progression.

RESULTS

Among the 752 patients treated, 41 (5.5%) experienced disease progression, including 7 (17.1%) exclusively local recurrences; 1 (2.4%) local and nodal recurrence; 1 (2.4%) local and nodal recurrence plus metastasis; 7 (17.1%) nodal recurrences plus metastases; and 25 (61%) exclusively distant metastases. The 5-year DFS, local recurrence-free survival, breast cancer-specific survival, and overall survival rates were 91.8% (95% confidence interval [CI], 88.6-94.2), 98.0% (95% CI, 96.1-99.1), 98.2% (95% CI, 96.5-99.1), and 87.5% (95% CI, 83.8-90.5), respectively. On univariate analysis, the administration of a boost, disease grade (grades 1 and 2 vs. 3), and molecular subtype (triple negative or human epidermal growth factor receptor 2 [HER2] positive, or luminal B vs. luminal A) significantly affected disease progression (P < .01). These findings were confirmed by multivariate analysis.

CONCLUSION

Hypo-RT is effective and well tolerated in the elderly population, and the routine use of a boost for patients over 65 years is not justified. Further studies on the boost issue are strongly advocated.

Partial breast irradiation with CyberKnife after breast conserving surgery: a pilot study in early breast cancer

BACKGROUND

Local recurrences after breast conserving treatment are mainly close to the original tumor site, and as such shorter fractionation strategies focused on and nearest mammary gland, i.e. accelerated partial breast irradiation (APBI), have been developed. Stereotactic APBI has been attempted, although there is little experience using CyberKnife (CK) for early breast cancer.

METHODS

This pilot study was designed to assess the feasibility of CK-APBI on 20 evaluable patients of 29 eligible, followed for 2 years. The primary endpoint was acute/sub-acute toxicity; secondary endpoints were late toxicity and the cosmetic result.

RESULTS

Mean pathological tumor size was 10.5 mm (±4.3, range 3-18), 8 of these patients were classified as LumA-like, 11 as LumB-like, and 1 as LumB-HER2-enriched. Using CK-APBI with Iris, the treatment time was approximately 60 min (range~ 35 to ~ 120). All patients received 30 Gy in five fractions delivered to the PTV. The median number of beams was 180 (IQR 107-213; range:56-325) with a median PTV isodose prescription of 86.0% (IQR 85.0-88.5; range:82-94). The median PTV was 88.1 cm3 (IQR 63.8-108.6; range:32.3-238.8). The median breast V100 and V50 was 0.6 (IQR 0.1-1.5; range:0-13) and 18.6 (IQR 13.1-21.7; range:7.5-37), respectively. The median PTV minimum dose was 26.2 Gy (IQR 24.7-27.6; range 22.3-29.3). Mild side effects were recorded during the period of observation. Cosmetic evaluations were performed by three observers from the start of radiotherapy up to 2 years. Patients' evaluation progressively increase from 60% to 85% of excellent rating; this trend was similar to that of external observer.

CONCLUSIONS

These preliminary results showed the safe feasibility of CK-APBI in early breast cancer, with mild acute and late toxicity and very good cosmetic results.

TRIAL REGISTRATION

The present study is registered at Clinicaltrial.gov ( NCT02896322 ). Retrospectively egistered August 4, 2016.

Mycobacterium tuberculosis infection modulates adipose tissue biology

Mycobacterium tuberculosis (Mtb) primarily resides in the lung but can also persist in extrapulmonary sites. Macrophages are considered the prime cellular habitat in all tissues. Here we demonstrate that Mtb resides inside adipocytes of fat tissue where it expresses stress-related genes. Moreover, perigonadal fat of Mtb-infected mice disseminated the infection when transferred to uninfected animals. Adipose tissue harbors leukocytes in addition to adipocytes and other cell types and we observed that Mtb infection induces changes in adipose tissue biology depending on stage of infection. Mice infected via aerosol showed infiltration of inducible nitric oxide synthase (iNOS) or arginase 1 (Arg1)-negative F4/80⁺ cells, despite recruitment of CD3⁺, CD4⁺ and CD8⁺ T cells. Gene expression analysis of adipose tissue of aerosol Mtb-infected mice provided evidence for upregulated expression of genes associated with T cells and NK cells at 28 days post-infection. Strikingly, IFN-γ-producing NK cells and Mtb-specific CD8⁺ T cells were identified in perigonadal fat, specifically CD8⁺CD44^-CD69⁺ and CD8⁺CD44^-CD103⁺ subpopulations. Gene expression analysis of these cells revealed that they expressed IFN-γ and the lectin-like receptor Klrg1 and down-regulated CD27 and CD62L, consistent with an effector phenotype of Mtb-specific CD8⁺ T cells. Sorted NK cells expressed higher abundance of Klrg1 upon infection, as well. Our results reveal the ability of Mtb to persist in adipose tissue in a stressed state, and that NK cells and Mtb-specific CD8⁺ T cells infiltrate infected adipose tissue where they produce IFN-γ and assume an effector phenotype. We conclude that adipose tissue is a potential niche for Mtb and that due to infection CD8⁺ T cells and NK cells are attracted to this tissue.

In 2015, tuberculosis (TB) affected 10.4 million individuals causing 1.8 million deaths per year. Yet, a much larger group– 2 billion people–harbors latent TB infection (LTBI) without clinical symptoms, but at lifelong risk of reactivation. The physiological niches of Mycobacterium tuberculosis (Mtb) persistence remain incompletely defined and both pulmonary and extrapulmonary sites have been proposed. Adipose tissue constitutes 15–25% of total body mass and is an active production site for hormones and inflammatory mediators. The increasing prevalence of obesity, has led to greater incidence of type 2 diabetes. These patients suffer from three times higher risk of developing TB, pointing to a potential link between adipose tissue and TB pathogenesis. In individuals with LTBI, Mtb survives in a stressed, non-replicating state with low metabolic activity and resting macrophages serve as preferred habitat and become effectors after appropriate stimulation. Here we demonstrate that Mtb can infect and persist within adipocytes where it upregulates stress-related genes. In vivo, relative proportions of leukocyte subsets infiltrating adipose tissue varied under different conditions of infection. During natural aerosol Mtb infection, distinct leukocyte subsets, including mononuclear phagocytes, Mtb-specific CD8⁺ T cells and NK cells infiltrated adipose tissue and became activated. Thus, our study shows that adipose tissue is not only a potential reservoir for this pathogen but also undergoes significant alteration during TB infection.

Trastuzumab and Hypofractionated Whole Breast Radiotherapy: A Victorious Combination?

INTRODUCTION

The purpose of this study was to examine the impact of trastuzumab on acute skin and cardiac toxicity in patients with breast cancer treated with chemotherapy with or without trastuzumab and adjuvant whole breast hypofractionated radiotherapy (hypo-RT).

MATERIALS AND METHODS

The study was conducted on 727 patients treated from April 2009 to October 2016. Patients received 42.4 Gy in 16 daily fractions (2.65 Gy per fraction). A boost was only administered in cases with grade (G) 3 primary tumor and close or positive margins. Acute and late toxicity was assessed prospectively during and after hypo-RT, based on the Radiation Therapy Oncology Group scale. Multivariable logistic regression models were used to examine the onset of acute skin toxicity (≥ G2) in the whole study population, and the impact of trastuzumab on the onset of acute skin (≥ G2) or cardiac toxicity in the subgroup of 176 patients given chemotherapy.

RESULTS

A total of 176 patients received chemotherapy with anthracycline and taxane, and 51 (29%) of them were also treated with trastuzumab. Acute G1, G2, and G3 skin toxicity occurred, respectively, in 56.8%, 27.3%, and 1.1% of the patients given chemotherapy alone, and in 64.7%, 19.6%, and 0% of those given trastuzumab as well. Among the patients given chemotherapy, left ventricular ejection fraction (LVEF) toxicity developed with a severity of G1 (LVEF < 60%-50%) in 12 (6.8%) patients, G2 (LVEF < 50%-40%) in 2 (1.1%) patients, and G3 (LVEF < 40%) in 1 (0.6%) patient. Among the patients also given trastuzumab, 7 (13.7%) patients had G1 LVEF toxicity, and 1 (2%) patient had G2 LVEF toxicity. We found that patients given trastuzumab were at higher risk of cardiac toxicity ≥ G1 (odds ratio, 4.3; P = .01), and at lower risk of acute skin toxicity ≥ G2 (odds ratio, 0.4; P = .03) than patients given chemotherapy alone.

CONCLUSIONS

This analysis showed that trastuzumab with adjuvant hypo-RT for patients with breast cancer was generally well-tolerated in routine clinical practice. A longer follow-up will be necessary to assess late cardiac toxicity.

Ten-year results of applying an original scoring system for addressing adjuvant therapy use after breast-conserving surgery for ductal carcinoma in situ of the breast

PURPOSE

Although large-scale randomised clinical trials have established that radiotherapy (RT) - alone or combined with hormonal therapy (HT) - is effective in reducing the risk of ipsilateral breast tumour recurrence (IBTR), overall survival does not seem to be improved by adjuvant therapies. We sought to ascertain whether specific criteria can be adopted to avoid RT with an acceptable rate of IBTR after breast-conserving surgery (BCS) achieving tumour-free margins.

PATIENTS AND METHODS

This non-randomised prospective study concerned the outcome of patients who underwent BCS for ductal carcinoma in situ (DCIS) and were prospectively assessed by means of an established scoring system based on width of free margins in association with age <40, presence of comedonecrosis, high grade, ER negativity and HER2 positivity, to orient the use of any adjuvant therapies.

RESULTS

From March 2000 to April 2006, a total of 224 patients were enrolled and followed up for this study. No adjuvant treatment was considered for 76 patients, while 53, 39 and 56 patients received HT alone, RT alone, and RT plus HT, respectively. After a median follow-up of 129.6 months, 25 patients developed an IBTR, corresponding to a yearly rate of 1.138% (95% CI: 0.769-1.684).

CONCLUSION

When the criteria considered in the present study were applied to address the use of adjuvant therapies, no RT was administered to 57.6% of patients, 33.9% received no adjuvant treatments at all, and the rate of IBTR was low. Our findings support the conviction that the risk/benefit of omitting RT may lean on the side of the latter in selected patients.

Complete remission in metastatic breast cancer: expecting the unexpected-results of a cross-sectional study

BACKGROUND

Complete response (CR) in metastatic breast cancer (MBC) is rare. This study aims at analyzing the characteristics and outcome of MBC patients achieving CR.

METHODS

We performed a cross-sectional analysis of clinical data from a consecutive series of MBC patients admitted at the Division of Medical Oncology of Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy, achieving CR following treatment for systemic disease and with at least 2 years of follow-up.

RESULTS

Seventy-six MBC patients with CR were identified during a calendar year. 47 patients (61.8%) achieved CR more than once, for a total of 123 cases. Median age at MBC diagnosis was 56 years (range 30-76). 52 patients (68.4%) presented with recurrent disease, 24 (31.6%) with de novo metastatic disease. The majority of patients (80.3%) had hormone receptor (HR) positive and 26 (34.2%) had HER2 overexpressing MBC. 54 patients (71.1%) had only one site of metastatic disease. 33 patients (43.4%) received a local approach as part of their treatment and 67 (54.5%) achieved CR during maintenance therapy. CRs were durable, as after a median follow-up of 8.3 years (interquartile range 5.8-11.0 years) 42 patients (55.3%) were alive with no evidence of disease.

CONCLUSIONS

Durable CRs can occur after systemic therapy alone or after combined systemic and local treatments. Most cases presented CR in the presence of limited disease spreading, not necessarily on first-line therapy. Our study highlights the crucial role of multidisciplinary approach to MBC and the benefit of maintenance treatment.

Evaluation of Local Oncologic Safety in Nipple-Areola Complex-sparing Mastectomy After Primary Chemotherapy: A Propensity Score-matched Study

BACKGROUND

Nipple-areola complex-sparing mastectomy (NSM), extending the concept of skin-sparing mastectomy, allows for the provision of a better cosmetic result. Large operable T2-T3 breast cancer might theoretically appear suitable for this surgical option as an alternative to conventional mastectomy or breast-conserving surgery, when a good response to primary chemotherapy has been achieved.

PATIENTS AND METHODS

From January 2009 to May 2013, 422 patients with invasive breast cancer were progressively accrued to NSM. Of the 422 patients, 361 underwent NSM as first-line treatment (NSM group), and 61 underwent surgery after primary chemotherapy (NSM-PC group). A total of 151 breast cancer patients, who had undergone PC and conventional total mastectomy (TM-PC group) from 2004 to 2009 were evaluated as comparative group with respect to the NSM-PC group. Using propensity score matching, local disease-free survival (LDFS) was evaluated comparatively.

RESULTS

The rate of nipple-areola involvement in the NSM and NSM-PC groups was 13.3% and 9.8%, respectively (P = .539). The nipple-areola involvement in the NSM and NSM-PC groups was significantly associated with the tumor size (odds ratio [OR], 1.48; 95% confidence interval [CI], 1.13-1.95; P = .004), plurifocal or pluricentric tumor (OR, 3.18; 95% CI, 1.72-5.89; P < .001), and the presence of an intraductal component (OR, 2.38; 95% CI, 1.22-4.64; P = .011). The LDFS in the NSM-PC and TM-PC matched cohorts did not show a significant difference, with a 4-year LDFS of 0.89 (95% CI, 0.77-0.95) and 0.93 (95% CI, 0.83-0.97), respectively (hazard ratio [HR], 1.31; 95% CI, 0.40-4.35; P = .655). The NSM-PC cohort was also compared with the NSM cohort in terms of LDFS using 2 different matching criteria, with the tumor size before and after neoadjuvant chemotherapy as the balancing covariate. In the first of the 2 comparisons, the hazards of local relapse were comparable between the 2 matched groups (HR, 1.23; 95% CI, 0.37-4.04; P = .739). In the second comparison, the NSM-PC patients showed a significant greater hazard of local relapse than did the NSM patients (HR, 3.60; 95% CI, 1.10-11.80; P = .035).

CONCLUSION

NSM might be a valuable option for large breast cancer treated by primary chemotherapy. The rate of local relapse seemed to be related to the disease stage, and no significant association with the type of surgery was detected.

Factors influencing acute and late toxicity in the era of adjuvant hypofractionated breast radiotherapy

PURPOSE

To evaluate toxicity in breast cancer patients treated with anthracycline and taxane based chemotherapy and whole breast hypofractionated radiotherapy, and to identify the risk factors for toxicity.

METHODS AND MATERIALS

537 early breast cancer patients receiving hypofractionated radiotherapy after conservative surgery were enrolled from April 2009 to December 2014, in an Italian cancer institute. The dose was 42.4 Gy in 16 daily fractions, 2.65 Gy per fraction. The boost to the tumor bed was administered only in grade III breast cancer patients and in patients with close or positive margins. Acute and late toxicity were prospectively assessed during and after radiotherapy according to RTOG scale. The impact of patients clinical characteristics, performed treatments and dose inhomogeneities on the occurrence of an higher level of acute skin toxicity and late fibrosis has been evaluated by univariate and multivariate analysis.

RESULTS

The mean age was 74 (range 46-91 yrs). 27% of patients received boost. 22% of cases (n = 119) received also chemotherapy. The median follow-up was 32 months. G1 and G2/G3 acute skin toxicity were 61.3% and 20.5% and G1 and G2/G3 late fibrosis 12.6% and 4.3% respectively. Chemotherapy (p = 0.04), diabetes (p = 0.04) and boost administration (p < 0.01) were found to be statistically significant on the occurrence of late fibrosis, but a multivariate analysis did not show any factors connected. The boost administration (p < 0.01), the breast volume (p = 0.05), dose inhomogeneities (p < 0.01) and boost volume (p = 0.04) were found to be statistically significant as concerns the occurrence of acute skin reaction at the univariate analysis, but only the boost administration (p = 0.02), at multivariate analysis.

CONCLUSIONS

The results of our study, according to the large randomized trials, confirmed that hypofractionated whole breast irradiation is safe, and only the boost administration seems to be an important predictor for toxicity. Chemotherapy does not impact on acute and late skin toxicity.

Comparison of two radiation techniques for the breast boost in patients undergoing neoadjuvant treatment for breast cancer

OBJECTIVE

After breast conservative surgery (BCS) and whole-breast radiotherapy (WBRT), the use of boost irradiation is recommended especially in patients at high risk. However, the standard technique and the definition of the boost volume have not been well defined.

METHODS

We retrospectively compared an anticipated pre-operative photon boost on the tumour, administered with low-dose fractionated radiotherapy, and neoadjuvant chemotherapy with two different sequential boost techniques, administered after BCS and standard adjuvant WBRT: (1) a standard photon beam (2) and an electron beam technique on the tumour bed of the same patients. The plans were analyzed for the dosimetric coverage of the CT-delineated irradiated volume. The minimal dose received by 95% of the target volume (D95), the minimal dose received by 90% of the target volume (D90) and geographic misses were evaluated.

RESULTS

15 patients were evaluated. The sequential photon and electron boost techniques resulted in inferior target volume coverage compared with the anticipated boost technique, with a median D95 of 96.3% (range 94.7-99.6%) and 0.8% (range 0-30%) and a median D90 of 99.1% (range 90.2-100%) and 54.7% (range 0-84.8%), respectively. We observed a geographic miss in 26.6% of sequential electron plans. The results of the anticipated boost technique were better: 99.4% (range 96.5-100%) and 97.1% (range 86.2-99%) for median D90 and median D95, respectively, and no geographic miss was observed. We observed a dose reduction to the heart, with left-sided breast irradiation, using the anticipated pre-operative boost technique, when analyzed for all dose-volume parameters. When compared with the sequential electron plans, the pre-operative photon technique showed a higher median ipsilateral lung Dmax.

CONCLUSION

Our data show that an anticipated pre-operative photon boost results in a better coverage with respect to the standard sequential boost while also saving the organs at risk and consequently fewer side effects.

ADVANCES IN KNOWLEDGE

This is the first dosimetric study that evaluated the association between an anticipated boost and neoadjuvant chemotherapy treatment.