Background: Both dose and linear energy transfer (LET) could play a substantial role in adverse event (AE) initialization of cancer patients treated with pencil-beam-scanning (PBS) proton therapy. However, not all the voxels within the AE regions are directly induced from the dose and LET effect. It is important to study the synergistic effect of dose and LET in AE initialization by only including a subset of voxels that are dosimetrically important. Purpose: To perform exploratory investigation of the dose and LET effects upon AE initialization in PBS using seed spots analysis. Methods: A total of 113 head-and-neck (H&N) cancer patients receiving curative PBS were included. Among them, 20 patients experienced unanticipated CTCAEv4.0 grade ≥3 AEs (AE group) and 93 patients did not (control group). Within the AE group, 13 AE patients were included in the seed spot analysis to derive the descriptive features of AE initialization and the remaining 7 mandible osteoradionecrosis patients and 93 control patients were used to derive the feature-based volume constraint of mandible osteoradionecrosis. The AE regions were contoured and the corresponding dose-LET volume histograms of AE regions were generated for all patients in the AE group. We selected high LET voxels (the highest 5% of each dose bin) with a range of moderate-to-high dose (≥∼40-Gy relative biological effectiveness) as critical voxels. Critical voxels that were contiguous with each other were grouped into clusters. Each cluster was considered a potential independent seed spot for AE initialization. Seed spots were displayed in a 2D dose-LET plane based on their mean dose and LET to derive the descriptive features of AE initialization. A volume constraint of mandible osteoradionecrosis was then established based on the extracted features using a receiver operating characteristic curve. Results: The product of dose and LET (xBD) was found to be a descriptive feature of seed spots leading to AE initialization in this preliminary study. The derived xBD volume constraint for mandible osteoradionecrosis showed good performance with an area under curve of 0.87 (sensitivity of 0.714 and specificity of 0.807 in the leave-one-out cross-validation) for the very limited patient data included in this study. Conclusion: Our exploratory study showed that both dose and LET were observed to be important in AE initializations. The derived xBD volume

Purpose The aim of the study was to assess the diagnostic performance of fluciclovine positron emission tomography (PET)/computerized tomography (CT) in post-radical prostatectomy prostate cancer patients with rising prostate-specific antigen (PSA) ≤0.5 ng/mL, and identify the associated predictive factors of positive studies. Patients and methods From 30 June 2017 to 9 August 2019, patients with post-radical prostatectomy prostate cancer who underwent F-18 fluciclovine PET/CT and had PSA level within 2-week interval (PSAPET) ≤0.5 ng/mL were enrolled into this single-institution retrospective study. Data on tumor characteristics, including Gleason scores, extra-prostatic extension, seminal vesicle invasion, surgical margin and nodal metastasis, PSA after radical prostatectomy, previous hormonal therapy, PSA doubling time (PSADT), scanner type, PSAPET and site of recurrence were collected. Comparison of these factors between groups of positive and negative fluciclovine PET/CT was done by using Mann–Whitney U-test and Fisher’s exact test. Results Of 94 eligible patients with post-radical prostatectomy prostate cancer, 10 patients had positive studies (10.6%). Detection rate at PSAPET 0.1, 0.2, 0.3, 0.4 and 0.5 ng/mL were 0% (0/11), 0% (0/15), 20% (6/30), 4% (1/25) and 23.1% (3/13), respectively. Upon multivariate analysis of clinical factors, only a PSADT <3 months (P = 0.023) was shown to have a statistically significant correlation with a positive study. Conclusion In post-radical prostatectomy prostate cancer patients with rising PSA 0.1–0.5 ng/mL, the sensitivity of F-18 fluciclovine PET/CT for identifying tumor recurrence/metastases is poor with an overall detection rate of 10.6%. Larger prospective studies are required to validate these findings.

Pitchaya Thongkhao, et al: Effects of Regular Bra-wearing on Acute Skin Toxicity in Breast-conserving RadiotherapyBreast cancer is the most common cancer in Thai women with the annual Age-Standardized Rate (ASR) per 100,000 being 31.4 in 2015 [1]. According to breast cancer treatments, breast conserving therapy is one of the loco-regional treatment options. Radiotherapy after wide local excision reduces the locoregional recurrence rate as well as the risk of breast cancer death [2][3][4]. Conventional radiotherapy regimens, after breast conservation surgery, deliver a total dose of 46-50 Gy in 23-25 daily fractions over 5 weeks [3][4][5][6][7]. A boost to the tumor bed is recommended in patients with a higher risk of recurrences with the typical boost doses being 10-16 Gy in 4-8 fractions [5-7-12].Acute skin toxicity is the most common side effect of Abstract Purpose: To evaluate the effects of regular bra-wearing during radiotherapy on acute skin toxicity (AST) and the Quality of Life (QOL) in women with breast conserving therapy (BCT). Methods: A prospective study of 99 patients with any stage of breast cancer who underwent BCT. Patients were instructed to wear an appropriate bra then they were classified by total hours of wearing a bra during the radiotherapy treatment course into Non-Bra-Wearing (NBW) (0 hr.) and Bra-Wearing (BW) groups (>0 hr.). The AST was assessed weekly and one week after treatment end by CTCAE v 4.03. The QOL was assessed before and one week after treatment end by The Functional Assessment of Cancer Therapy-Breast Cancer (FACT-B) Thai version 4. Results: 66 patients were in the BW group and 33 patients were in the NBW group. The rate of ≥ G2 AST was lower in the BW group compared to the NBW group (16.7% vs. 54.5%, p<0.001, respectively). In the multivariate analysis, the statistically significant factors that were associated with increased the risk of ≥ G2 AST were NBW (0 hr.) (p<0.001), high body mass index (p=0.001), and the high percentage of maximum dose (p=0.043). There were no differences in all parts of after treatment FACT-B between the two groups (118.4 vs. 114.7, p=0.256, respectively). Conclusions: Regular BW during radiotherapy is not associated with an increased risk of ≥ G2 acute skin toxicity and does not affect the QOL compared to NBW.

Objective: Cervical cancer is the second most common cancer in Thailand. For cervical cancer, there is no cancer specific quality of life questionnaire. This study aims to develop and validate Thai FACT-CX. Methods: The cross-sectional study included all women aged ≥18 years with stage IB2-IIIB who planned to undergo chemoradiotherapy. Those who did not understand Thai language, had other cancers (except for skin cancer), were diagnosed with impaired cognition and/or overt psychosis, and major depression were excluded. The FACT-CX comprises 42 items with 5 domains and a score range of 0-168. The WHOQOL-BREF comprises 26 items with 4 domains and a score range of 26-130. The participants were interviewed about demographic and clinical data. Both questionnaires were self-completed. Factor analysis was used to compare our data with the previous structure. The reliability used Cronbach’s alpha. Spearman’s correlation determined relationship between the domains of the modified FACT-CX and WHOQOL-BREF. Both questionnaires were compared with socioeconomic and clinical variables using the Ranksum test and Kruskal-Wallis test. P-value > 0.05 considered significant. Results: The 245 participants included. Expletory factor analysis revealed an accumulative variance of 0.42 with 4 factors. The internal consistency was 0.84, 0.81, 0.78, 0.77 and 0.90 for perception of self, suffering symptoms, family support, life resilience and total questions. There was correlation between the domains of the modified FACT-CX and WHOQOL-BREF. Both the modified FACT-CX and WHOQOL-BREF could identify differences between the groups of patients. Conclusion: Finally, the Thai modified FACT-CX was found to be reliable and valid for measuring quality of life among untreated cervical cancer patients.

Recently, deep learning with generative adversarial networks (GANs) has been applied in multi-domain image-to-image translation. This study aims to improve the image quality of cone-beam computed tomography (CBCT) by generating synthetic CT (sCT) that maintains the patient’s anatomy as in CBCT, while having the image quality of CT. As CBCT and CT are acquired at different time points, it is challenging to obtain paired images with aligned anatomy for supervised training. To address this limitation, the study incorporated a registration network (RegNet) into GAN during training. RegNet can dynamically estimate the correct labels, allowing supervised learning with noisy labels. The study developed and evaluated the approach using imaging data from 146 patients with head and neck cancer. The results showed that GAN trained with RegNet performed better than those trained without RegNet. Specifically, in the UNIT model trained with RegNet, the mean absolute error (MAE) was reduced from 40.46 to 37.21, the root mean-square error (RMSE) was reduced from 119.45 to 108.86, the peak signal-to-noise ratio (PSNR) was increased from 28.67 to 29.55, and the structural similarity index (SSIM) was increased from 0.8630 to 0.8791. The sCT generated from the model had fewer artifacts and retained the anatomical information as in CBCT.