Modern-era radiotherapy and ischaemic heart disease-related mortality outcomes in Asian breast-cancer patients.

Introduction: Left-sided breast-cancer patients treated with adjuvant radiotherapy (RT) before the 1990s were associated with increased risk of cardiac mortality. Modern RT techniques have since improved, resulting in lower radiation doses to the heart. However, concerns regarding cardiac toxicity remain. In a retrospective cohort study, we compare the ischaemic heart disease (IHD)-related mortality of left-sided versus right-sided breast-cancer patients. We present the results of the cardiac mortality and all-cause mortality risk of Asian breast-cancer survivors treated with RT in Singapore. Material and methods: A total of 14,419 Asian women from a single institution were treated for breast cancer from 2000 to 2016. A systematic mortality follow-up was conducted until December 2015. The effect of breast cancer laterality on IHD-related mortality and on overall mortality was investigated. Mean heart doses were recorded for patients from 2010-2016. Results: In the irradiated group (n = 9556), we found no difference in IHD-related mortality or overall mortality when comparing the left- and right-sided breast cancers. The hazard ratio of cardiac mortality for left-sided versus right-sided RT was 0.94 (95% CI: 0.64-1.38). The hazard ratio for all-cause mortality was 1.03 (95% CI: 0.94-1.13). Conclusions: Our study of Asian cancer patients did not reveal a significant increase in the risk of IHD-related mortality or overall mortality comparing left- vs. right-sided breast cancers in modern-era RT.

Volumetric modulated arc therapy in prostate cancer patients with metallic hip prostheses in a UK centre.

AIM: This study aimed to investigate whether IMRT using VMAT is a viable and safe solution in dose escalated RT in these patients. BACKGROUND: An increasing number of prostate cancer patients are elderly and have hip prostheses. These implants pose challenges in radiotherapy treatment planning. Although intensity modulated radiotherapy (IMRT) is commonly used, there is a lack of clinical studies documenting its efficacy and toxicities in this subgroup of patients. MATERIALS AND METHODS: The data from 23 patients with hip prostheses and non-metastatic prostate cancer treated with VMAT (volumetric modulated arc therapy) between 2009 and 2011, were retrospectively analyzed. Baseline characteristics, treatment details and outcome data were collected on all patients. The median follow up was 40.9 months. MRI-CT image fusion was performed and the treatment plans were created using RapidArc™ (RA) techniques utilizing 1 or 2 arcs and 10 MV photon beams. RESULTS: 96% of patients were treated with a dose of 72 Gy/32 fractions over 44 days. 21/23 plans met the PTV targets. The mean homogeneity index was 1.07. 20/23 plans met all OAR constraints (rectum, bladder). Two plans deviated from rectal constraints, four from bladder constraints; all were classed as minor deviations. One patient experienced late grade 3 genitourinary toxicity. Three other patients experienced late grade 2 or lower gastrointestinal toxicity. One patient had biochemical failure and one had a non-prostate cancer related death. CONCLUSIONS: VMAT provides an elegant solution to deliver dose escalated RT in patients with unilateral and bilateral hip replacements with minimal acute and late toxicities.

Impacted maxillary canine: Assessment of prevalence, severity and location of root resorption on maxillary incisors: A retrospective CBCT study.

BACKGROUND: The maxillary permanent canine is one of the most frequently impacted teeth, which often requires multidisciplinary management. A common complication of canine impaction is root resorption of the adjacent dentition. The aim of this retrospective study was to report the prevalence of root resorption of maxillary incisors adjacent to impacted maxillary canines from small volume CBCT images by trained clinicians. A secondary objective was to report the location and severity of root resorption. MATERIAL AND METHODS: CBCT images of patients with impacted maxillary canines (unilateral and bilateral) who attended a joint orthodontic/surgical multidisciplinary clinic were screened. Descriptive statistics were used to investigate associations of patient characteristics and presence of root resorption. Generalized estimating equations (GEE) logistic regression model were used to identify predictors of root resorption. RESULTS: In all, 148 impacted maxillary canines (122 patients) were analysed. The majority of patients were under 18 years of age (71.6%) with impacted canines present in more females (68.2%) than males (31.8%). Maxillary lateral incisors showed the highest prevalence of root resorption (38.5%). The apical region was the most common location of resorption for lateral incisors (20.9%) with a variable degree of severity evident: slight (10.1%), moderate (15.6%), and severe (12.8%). Although no significant predictors of root resorption were identified, a weak association was evident for age and root development. CONCLUSIONS: In this cohort of patients, the roots of maxillary lateral incisors are most likely to suffer from root resorption in the presence of an impacted maxillary canine. Clinicians should consider the extent, location and severity of resorption of adjacent teeth when planning treatment decisions and mechanics in cases of impacted maxillary canines.

A Prospective Randomized Controlled Trial to Compare the Use of Conventional Dark-Ink Tattoo and Ultraviolet-Ink Tattoo for Patients Undergoing Breast Radiation Therapy.

PURPOSE: Permanent tattoo marks used in radiation therapy remain for the duration of treatment and essentially for the rest of the patient's life. This study compared the initial positioning setup errors and body image perception between patients with ultraviolet (UV) and conventional dark ink tattoos. METHODS AND MATERIALS: Thirty-four patients from February 2018 to March 2019, who underwent radiation therapy (RT) to the breast or chest wall for ductal carcinoma in situ or breast cancer were prospectively recruited and randomized (1:1) to receive either conventional dark ink or UV ink tattoos. Each patient received the assigned tattoos during computed tomography (CT) simulation and initial treatment setup shifts were compared. A 9-item body-image survey was administered to all patients at 3 time points: CT simulation, last week of RT, and 6 weeks post-RT. Feedback from CT and treatment staff in terms of setup time and challenges were collated. RESULTS: The median age of the patient cohort was 46 years old. No statistically significant difference was observed between the mean setup errors for the conventional dark ink group (0.11 cm inferior, 0.01 cm left, 0.11 cm posterior) and UV ink group (0.01 cm superior, 0.01 cm right, 0.06 cm posterior; P = NS). Similar responses were observed in the body-image survey between the 2 groups across all time points (P = NS). The majority of the patients (dark ink 82.3% vs UV ink 88.2%) did not feel less sexually attractive as a result of the tattoo at 6 weeks post-RT. At 6 weeks post-RT, patients in both groups were satisfied with the appearance of the tattoo and did not feel cautious about their choice of clothes (82.4% vs 88.2%; P = NS). In addition, 88.6% of staff (n = 35) felt minimum effect of UV ink on the overall setup time, and 94.3% found no difficulty localizing the UV ink tattoos during patient positioning. CONCLUSIONS: No difference in setup accuracy was found using UV ink tattoos, and it could be implemented clinically with minimal effect on the existing workflow. Patients expressed high satisfaction and self-confidence with the use of UV ink tattoos.

The Impact of Radiotherapy and Histological Risk Factors on Outcomes in Malignant Phyllodes Tumors.

PURPOSE: Breast phyllodes tumors (PT) are classified into benign, borderline, and malignant grades based on histopathologic characteristics. Specific to malignant PT (MPT), surgery is the mainstay yet relapse rates are high and knowledge gaps in the literature exist regarding adjuvant radiotherapy (RT). We aimed to investigate the outcomes of patients with MPT treated in a tertiary Asian institution. METHODS AND MATERIALS: Patients with nonmetastatic MPT treated from February 1992 to June 2019 were analyzed retrospectively. RT details and relapse fields were studied. Outcomes of patients with and without RT were compared and hazard ratios were calculated using Cox proportional hazard test. Multivariable analysis was performed. RESULTS: Twenty-two of 89 patients received adjuvant RT and the median dose was 60 Gy. In the no-RT group, 4 patients received RT on relapse and had no further recurrences; a further 2 received RT for fungating relapses with good symptomatic relief. RT was only increasingly prescribed after 2004. Median follow-up in the RT group was 3.31 years, compared with 6.17 years in the no-RT group. In the RT group, 15 patients (68.2%) underwent mastectomy, versus 39 (58.2%) in the no-RT group. One patient in the RT group developed an infield local relapse, compared with 21 of 67 patients in the no-RT group. Multivariate model showed that RT decreased risk of locoregional failure (hazard ratio 0.12, 95% confidence interval [CI] 0.02-0.92, P = .04). Three-year locoregional recurrence-free survival was higher in the RT group, 92.3% (95% CI, 78.9-100) versus 73.3% (95% CI, 63.1-85.1) in the no-RT group (P = .03). There were no differences in 3-year survival. CONCLUSIONS: We recommend that adjuvant radiotherapy be discussed for malignant PT for local control, even after mastectomy.

Are heart doses associated with survival in patients with non-small cell lung cancer who received post-operative thoracic radiotherapy?: A national population-based study.

The aim of this retrospective national cohort study is to assess the association between various radiation heart dosimetric parameters (RHDPs), acute myocardial infarct (AMI) and overall survival (OS) outcomes in non-small cell lung cancer (NSCLC) patients treated with post-operative thoracic radiotherapy (PORT) using contemporary radiation techniques.We identified patients with stage I to III NSCLC treated with PORT at the 2 national cancer institutions from 2007 to 2014. We linked their electronic medical records to the national AMI and death registries. Univariable Cox regression was performed to assess the association between various RHDPs, AMI, and OS.We included 43 eligible patients with median follow-up of 36.6 months. Median age was 64 years. Majority of the patients had pathological stage III disease (72%). Median prescription dose was 60Gy. Median mean heart dose (MHD) was 9.4Gy. There were no AMI events. The 5-year OS was 34%. Univariable Cox regression showed that age was significantly associated with OS (hazard ratio, 1.06; 95% confidence interval, 1.01 to 1.10; P = .008). Radiation heart doses, including MHD, volume of heart receiving at least 5, 25, 30, 40, 50Gy and dose to 30% of heart volume, were not significantly associated with OS.There is insufficient evidence to conclude that RHDPs are associated with OS for patients with NSCLC treated with PORT in this study. Studies with larger sample size and longer term follow-up are needed to assess AMI outcome.

An assessment of the magnitude of intra-fraction movement of head-and-neck IMRT cases and its implication on the action-level of the imaging protocol.

BACKGROUND AND PURPOSE: A planning margin ⩽3 mm is employed in some head-and-neck IMRT cases due to the proximity of critical structures. This study aims to explore the need to redefine the action-level in the head-and-neck imaging protocol in consideration of the intra-fraction movement. MATERIAL AND METHODS: This is a local study of 18 patients treated using the same immobilisation system and setup protocol. Post-treatment orthogonal pair of kilovoltage X-ray images was acquired on the first three days of treatment. 106 sets of pre- and post-treatment kV X-ray images acquired over 53 fractions were analysed against the treatment planning DRR for calculation of intra-fraction movement. RESULTS: Individual mean intra-fraction movement in all directions ranged from -1.8 to 1.1 mm. Population mean (median) intra-fraction movement in the x-, y-, and z-planes were -0.1 mm (0 mm), -0.3 mm (-0.3 mm) and -0.2 mm (-0.2 mm) respectively. Intra-fraction movement in all three dimensions, x-, y- and z-planes were considered statistically significant (p<0.05). 7 out of 53 fractions (13.2%) were highlighted as the combined magnitude of the intra-fraction motion with the uncorrected pre-treatment setup errors had exceeded the boundaries of given margins. CONCLUSIONS: 3 mm-AL was not adequate to account for intra-fraction movement when the CTV-PTV margin was ⩽3 mm and should be excluded from the routine imaging protocol and daily image-guided radiotherapy should be employed. Adjusting the action-level to 2 mm would allow a more confident approach in delivery of the prescribed dose in head-and-neck IMRT cases.