Intestinal microbiota composition is predictive of radiotherapy-induced acute gastrointestinal toxicity in prostate cancer patients.

BACKGROUND: The search for factors beyond the radiotherapy dose that could identify patients more at risk of developing radio-induced toxicity is essential to establish personalised treatment protocols for improving the quality-of-life of survivors. To investigate the role of the intestinal microbiota in the development of radiotherapy-induced gastrointestinal toxicity, the MicroLearner observational cohort study characterised the intestinal microbiota of 136 (discovery) and 79 (validation) consecutive prostate cancer patients at baseline radiotherapy. METHODS: Gastrointestinal toxicity was assessed weekly during RT using CTCAE. An average grade >1.3 over time points was used to identify patients suffering from persistent acute toxicity (endpoint). The microbiota of patients was quantified from the baseline faecal samples using 16S rRNA gene sequencing technology and the Ion Reporter metagenomic pipeline. Statistical techniques and computational and machine learning tools were used to extract, functionally characterise, and predict core features of the bacterial communities of patients who developed acute gastrointestinal toxicity. FINDINGS: Analysis of the core bacterial composition in the discovery cohort revealed a cluster of patients significantly enriched for toxicity, displaying a toxicity rate of 60%. Based on selected high-risk microbiota compositional features, we developed a clinical decision tree that could effectively predict the risk of toxicity based on the relative abundance of genera Faecalibacterium, Bacteroides, Parabacteroides, Alistipes, Prevotella and Phascolarctobacterium both in internal and external validation cohorts. INTERPRETATION: We provide evidence showing that intestinal bacteria profiling from baseline faecal samples can be effectively used in the clinic to improve the pre-radiotherapy assessment of gastrointestinal toxicity risk in prostate cancer patients. FUNDING: Italian Ministry of Health (Promotion of Institutional Research INT-year 2016, 5 × 1000, Ricerca Corrente funds). Fondazione Regionale per la Ricerca Biomedica (ID 2721017). AIRC (IG 21479).

A monocentric, open-label randomized standard-of-care controlled study of XONRID®, a medical device for the prevention and treatment of radiation-induced dermatitis in breast and head and neck cancer patients.

BACKGROUND: This study was an open-label, 2-arms, monocentric, randomized clinical trial comparing Xonrid®, a topical medical device, versus standard of care (SOC) in preventing and treating acute radiation dermatitis (ARD) in Head and Neck Cancer (HNC) and Breast Cancer (BC) patients undergoing radiotherapy (RT). METHODS: Eligible HNC and BC patients were randomized 1:1 to receive Xonrid® + SOC or SOC during RT. Patients were instructed to apply Xonrid® on the irradiated area three times daily, starting on the first day of RT and until 2 weeks after RT completion or until the development of grade ≥ 3 skin toxicity. The primary endpoint was to evaluate the proportion of patients who developed an ARD grade < 2 at the 5th week in both groups. Secondary endpoints were median time to grade 2 (G2) skin toxicity onset; changes in skin erythema and pigmentation and trans-epidermal water loss (TEWL); patient-reported skin symptoms. All patients were evaluated at baseline, weekly during RT and 2 weeks after treatment completion. The evaluation included: clinical toxicity assessment; reflectance spectrometry (RS) and TEWL examination; measurement of patients' quality of life (QoL) through Skindex-16 questionnaire. RESULTS: Eighty patients (40 for each cancer site) were enrolled between June 2017 and July 2018. Groups were well balanced for population characteristics. All BC patients underwent 3-Dimensional Conformal RT (3D-CRT) whereas HNC patients underwent Volumetric-Modulated Arc Therapy (VMAT). At week 5 the proportion of BC patients who did not exhibit G2 ARD was higher in Xonrid® + SOC group (p = 0.091). In the same group the onset time of G2 ARD was significantly longer than in SOC-alone group (p < 0.0491). For HNC groups there was a similar trend, but it did not reach statistical significance. For both cancer sites, patients' QoL, measured by the Skindex-16 score, was always lower in the Xonrid® + SOC group. CONCLUSION: Despite the failure to achieve the primary endpoint, this study suggests that Xonrid® may represent a valid medical device in the prevention and treatment of ARD at least in BC patients, delaying time to develop skin toxicity and reducing the proportion of patients who experienced G2 ARD during RT treatment and 2 weeks later. TRIAL REGISTRATION: The study was approved by the Ethical Committee of Fondazione IRCCS Istituto Nazionale dei Tumori di Milano (INT 52/14 - NCT02261181 ). Registered on ClinicalTrial.gov on 21st August 2017.

Hypofractionated irradiation in 794 elderly breast cancer patients: An observational study.

To assess the efficacy, and the acute and late toxicity of hypofractionated radiotherapy (Hypo-RT), and the impact of age and comorbidities on disease progression and death in elderly breast cancer (BC) patients. Women aged ≥65 years who received Hypo-RT (42.4 Gy in 16 fractions, plus a boost for high-risk patients) were considered for the present analysis. Competing risk analysis was used to estimate the 5-year cumulative incidence of BC progression and BC-related death, calculating the adjusted subhazard ratios (SHR) with 95% confidence intervals (95%CI) in relation to age, hypertension-augmented Charlson Comorbidity Index (hCCI), tumor characteristics, and chemotherapy. The sample included 794 patients with a median age of 74 years (range 65-91 years). At the baseline, 70% of these patients had at least one comorbidity. With a median follow-up of 48.3 months, the 5-year cumulative incidence of BC progression and BC-related death was 6.7% (95%CI 4.8%-9.2%) and 2.3% (95%CI 1.2%-3.9%), respectively. Old age (≥80 years) and a high burden of comorbidity (hCCI ≥ 2) were independently associated with BC progression. Hypo-RT is safe in elderly BC patients, but age and comorbidities influence BC progression. Further studies are warranted.

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.

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.

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.

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.

Variability in axillary lymph node delineation for breast cancer radiotherapy in presence of guidelines on a multi-institutional platform.

AIM: To quantify the variability between radiation oncologists (ROs) when outlining axillary nodes in breast cancer. MATERIAL AND METHODS: For each participating center, three ROs with different levels of expertise, i.e., junior (J), senior (S) and expert (E), contoured axillary nodal levels (L1, L2, L3 and L4) on the CT images of three different patients (P) of an increasing degree of anatomical complexity (from P1 to P2 to P3), according to contouring guidelines. Consensus contours were generated using the simultaneous truth and performance level estimation (STAPLE) method. RESULTS: Fifteen centers and 42 ROs participated. Overall, the median Dice similarity coefficient was 0.66. Statistically significant differences were observed according to the level of expertise (better agreement for J and E, worse for S); the axillary level (better agreement for L1 and L4, worse for L3); the patient (better agreement for P1, worse for P3). Statistically significant differences in contouring were found in 18% of the inter-center comparison. Less than a half of the centers could claim to have a good agreement between the internal ROs. CONCLUSIONS: The overall intra-institute and inter-institute agreement was moderate. Central lymph-node levels were the most critical and variability increased as the complexity of the patient's anatomy increased. These findings might have an effect on the interpretation of results from multicenter and even mono-institute studies.

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.

Axillary coverage by whole breast irradiation in 1 to 2 positive sentinel lymph nodes in breast cancer patients.

PURPOSE: To evaluate the dosimetric coverage of axillary levels I, II, and III obtained with standard whole breast irradiation in 1 to 2 positive sentinel lymph nodes (SLNs) patients not submitted to axillary lymph nodes dissection (ALND), and to compare the lymph nodes areas coverage obtained with 3D conformal radiation therapy, intensity-modulated radiotherapy (IMRT), and volumetric modulated arc therapy (VMAT). METHODS: Patients with 1 to 2 positive SLNs undergoing breast-conserving therapy, without ALND, were included in the analysis. For each patient, 3 treatment plans were performed: a 3D conventional tangential plan, a static IMRT plan, and a volumetric IMRT, designed to encompass the entire breast parenchyma. The volumes of axillary levels I, II, and III receiving 90% and 95% (V90, V95) of the whole breast prescribed dose were evaluated. Dose-volume histograms were compared by means of the Friedman test. RESULTS: Ten patients were enrolled. All defined breast volumes received >95% of the prescribed dose with the 3 techniques. Median V95 for axillary level I was 26.4% (range 4.7%-61.3%) for 3D plans, 8.6% (range 0.64%-19.1%) for static IMRT plans, and 2.6% (range 0.4%-4.7%) for volumetric IMRT plans (p<0.001). Median V95 for axillary level II was 5.4% (range 0%-14.6%), 1.9% (range 0%-15%), and 2.6% (range 0.4%-4.7%) for 3D, static IMRT, and volumetric IMRT, respectively (p<0.001). CONCLUSIONS: Results of our analysis showed that standard 3D tangential whole breast irradiation failed to deliver a therapeutic dose to axillary levels I and II. The coverage was even lower using static and volumetric IMRT techniques.

Image guided hypofractionated radiotherapy and quality of life for localized prostate cancer: prospective longitudinal study in 337 patients.

PURPOSE: We prospectively analyzed quality of life in a cohort of patients with prostate cancer undergoing a course of hypofractionated image guided radiotherapy. MATERIALS AND METHODS: Between August 2006 and January 2011, 337 patients with a median age of 73 years who had cT1-T2N0M0 prostate cancer were eligible for this prospective, longitudinal study of hypofractionated image guided radiotherapy (70.2 Gy/26 fractions) using 1 of 3 image guided radiotherapy modalities (transabdominal ultrasound, x-ray or cone beam computerized tomography) available in our radiation oncology department. Patients completed 4 questionnaires before treatment, and 6, 12 and 24 months later, including the International Index of Erectile Function-5, International Prostate Symptom Score, and EORTC (European Organization for Research and Treatment of Cancer) prostate cancer specific QLQ-PR25 and QLQ-C30. RESULTS: Patient followup was updated to at least the last questionnaire time point. Median followup was 19 months. Significant deterioration in erectile function on the International Index of Erectile Function-5 was documented with time only in patients without androgen deprivation (p = 0.0002). No change with time was observed in urinary symptom related quality of life on the QLQ-PR25 or International Prostate Symptom Score. Slight deterioration in QLQ-PR25 bowel symptom related quality of life was observed (p = 0.02). Overall QLQ-C30 Global Health Status improved with time (p = 0.03). On univariate analysis it significantly correlated with the maximum RTOG (Radiation Therapy Oncology Group)/EORTC urinary and bowel late toxicity scores after radiotherapy. CONCLUSIONS: The regimen of hypofractionated image guided radiotherapy with multiple imaging modalities adopted in our radiation oncology department for localized prostate cancer might be a successful strategy for dose escalation with a limited impact on different aspects of quality of life with time.