Variation in Hounsfield unit calculated using dual-energy computed tomography: comparison of dual-layer, dual-source, and fast kilovoltage switching technique.

The purpose of the study is to investigate the variation in Hounsfield unit (HU) values calculated using dual-energy computed tomography (DECT) scanners. A tissue characterization phantom inserting 16 reference materials were scanned three times using DECT scanners [dual-layer CT (DLCT), dual-source CT (DSCT), and fast kilovoltage switching CT (FKSCT)] changing scanning conditions. The single-energy CT images (120 or 140 kVp), and virtual monochromatic images at 70 keV (VMI70) and 140 keV (VMI140) were reconstructed, and the HU values of each reference material were measured. The difference in HU values was larger when the phantom was scanned using the half dose with wrapping with rubber (strong beam-hardening effect) compared with the full dose without the rubber (reference condition), and the difference was larger as the electron density increased. For SECT, the difference in HU values against the reference condition measured by the DSCT (3.2 ± 5.0 HU) was significantly smaller (p < 0.05) than that using DLCT with 120 kVp (22.4 ± 23.8 HU), DLCT with 140 kVp (11.4 ± 12.8 HU), and FKSCT (13.4 ± 14.3 HU). The respective difference in HU values in the VMI70 and VMI140 measured using the DSCT (10.8 ± 17.1 and 3.5 ± 4.1 HU) and FKSCT (11.5 ± 21.8 and 5.5 ± 10.4 HU) were significantly smaller than those measured using the DLCT120 (23.1 ± 27.5 and 12.4 ± 9.4 HU) and DLCT140 (22.3 ± 28.6 and 13.1 ± 11.4 HU). The HU values and the susceptibility to beam-hardening effects varied widely depending on the DECT scanners.

Risk factors for local recurrence of keloids and hypertrophic scars after postoperative electron beam radiotherapy.

OBJECTIVE: Keloids and hypertrophic scars are benign fibroproliferative lesions that occur as a result of skin injury. Postoperative radiation therapy is used to reduce the recurrence rate because of the high recurrence rate with surgical treatment alone. This study aimed to identify the risk factors for recurrence after postoperative electron beam radiotherapy. MATERIALS AND METHODS: Patients with keloid or hypertrophic scars with at least one lesion and who underwent postoperative electron beam radiotherapy at our institution from June 2013 to March 2022 were included in the study, while patients with a follow-up period of fewer than three months were excluded. RESULTS: A retrospective analysis was performed on 94 lesions in 81 patients. Exactly two years after the treatment, the actuarial local control rate was 86.4%. The chest wall, shoulder, and suprapubic area were identified as high-risk recurrence sites. Compared to other body sites, these sites had significantly lower local control rates (two-year local control rates: 75.5% vs. 95.2%, P = 0.005). After multivariate analysis, treatment site (P = 0.014), male gender (P = 0.019), and younger age (P = 0.029) were revealed to be statistically significant risk factors for local recurrence. Risk factors for keloid recurrence after postoperative electron beam radiotherapy were therefore identified. CONCLUSION: This result could be used for follow-up and as a determinant for the optimal dose/fractionation of postoperative radiotherapy.

Curative Radiotherapy for Oropharyngeal Squamous Cell Carcinoma Stratified by p16 Status, According to the Eighth Edition American Joint Committee on Cancer Staging Manual: A Retrospective Study.

Background/Aim: The prevalence of oropharyngeal squamous cell carcinoma (OPSCC) is increasing worldwide. This retrospective study aimed to investigate the clinical outcomes of patients with OPSCC undergoing definitive radiotherapy, stratified according to their p16 status. Patients and Methods: A retrospective analysis was conducted on consecutive patients with OPSCC treated with curative external beam radiotherapy between May 2015 and September 2023. Clinical staging was determined by the eighth edition AJCC staging manual for p16 positive and negative OPSCC. All patients were treated with radiotherapy using a simultaneous integrated boost (SIB) with helical tomotherapy. The fractionation scheme, with or without chemotherapy, for the primary site and nodal lesions consisted of 2 Gy per fraction for a total dose of 70 Gy in 35 fractions over seven weeks. Results: This study included 76 patients with a median age of 66 years. With a median follow-up time of 32.6 months, the 3-year progression-free survival rate was significantly higher in p16 positive patients compared to p16 negative patients (79.6% vs. 42.5%, p<0.001). Concerning 54 patients with p16-positive tumors, the overall survival rates indicated excellent clinical outcomes for stage I, II, and III with results of 100%, 100%, and 88.1%, respectively. Conclusion: This retrospective study revealed the clinical outcomes of patients with OPSCC treated with radical radiotherapy, emphasizing the significance of p16 status. While acknowledging the limitations of the retrospective nature of this study, future prospective studies with larger cohorts and extended follow-up periods are needed to enhance evidence quality.

Long-term geometric quality assurance of radiation focal point and cone-beam computed tomography for Gamma Knife radiosurgery system.

To investigate the geometric accuracy of the radiation focal point (RFP) and cone-beam computed tomography (CBCT) over long-term periods for the ICON Leksell Gamma Knife radiosurgery system. This phantom study utilized the ICON quality assurance tool plus, and the phantom was manually set on the patient position system before the implementation of treatment for patients. The deviation of the RFP position from the unit center point (UCP) and the positions of the four ball bearings (BBs) in the CBCT from the reference position were automatically analyzed. During 544 days, a total of 269 analyses were performed on different days. The mean ± standard deviation (SD) of the deviation between measured RFP and UCP was 0.01 ± 0.03, 0.01 ± 0.03, and -0.01 ± 0.01 mm in the X, Y, and Z directions, respectively. The deviations with offset values after the cobalt-60 source replacement (0.00 ± 0.03, -0.01 ± 0.01, and -0.01 ± 0.01 mm in the X, Y, and Z directions, respectively) were significantly (p = 0.001) smaller than those before the replacement (0.02 ± 0.03, 0.02 ± 0.01, and -0.02 ± 0.01 mm in the X, Y, and Z directions, respectively). The overall mean ± SD of four BBs was -0.03 ± 0.03, -0.01 ± 0.05, and 0.01 ± 0.03 mm in the X, Y, and Z directions, respectively. Geometric positional accuracy was ensured to be within 0.1 mm on most days over a long-term period of more than 500 days.

Relationship between hydrogel spacer distribution and dosimetric parameters in linear-accelerator-based stereotactic body radiotherapy for prostate cancer.

PURPOSE: To explore the potential of quantitative parameters of the hydrogel spacer distribution as predictors for separating the rectum from the planning target volume (PTV) in linear-accelerator-based stereotactic body radiotherapy (SBRT) for prostate cancer. METHODS: Fifty-five patients underwent insertion of a hydrogel spacer and were divided into groups 1 and 2 of the PTV separated from and overlapping with the rectum, respectively. Prescribed doses of 36.25-45 Gy in five fractions were delivered to the PTV. The spacer cover ratio (SCR) and hydrogel-implant quality score (HIQS) were calculated. RESULTS: Dosimetric and quantitative parameters of the hydrogel spacer distribution were compared between the two groups. For PTV, D99% in group 1 (n = 29) was significantly higher than that in group 2 (n = 26), and Dmax , D0.03cc , D1cc , and D10% for the rectum were significantly lower in group 1 than in group 2. The SCR for prostate (89.5 ± 12.2%) in group 1 was significantly higher (p < 0.05) than that in group 2 (74.7 ± 10.3%). In contrast, the HIQS values did not show a significant difference between the groups. An area under the curve of 0.822 (95% confidence interval, 0.708-0.936) for the SCR was obtained with a cutoff of 93.6%, sensitivity of 62.1%, and specificity of 100%. CONCLUSIONS: The SCR seems promising to predict the separation of the rectum from the PTV in linear-accelerator-based SBRT for prostate cancer.

Hypofractionated Radiotherapy as a Standalone Treatment Modality for Locally Advanced Type B2 Thymoma in an Octogenarian Patient: 45 Gy in 15 Fractions.

Thymic epithelial tumors (TETs), particularly type B2 thymomas, are rare neoplasms primarily found in the anterior mediastinum. The current therapeutic approach includes surgery, chemotherapy, and radiotherapy, but there is limited research on radiotherapy as a standalone treatment. This case report aims to elucidate the clinical outcomes of hypofractionated radiotherapy as a standalone treatment for locally advanced type B2 thymoma, offering insights into its potential efficacy and role in clinical practice.

Survival Following Palliative Radiotherapy for Head and Neck Squamous Cell Carcinoma: Examining Treatment Indications in Elderly Patients.

Background/Aim: This study investigated the survival outcomes of patients with head and neck squamous cell carcinoma (HNSCC) undergoing palliative radiotherapy, particularly focusing on challenges and factors associated with older age, providing insights into appropriate palliative radiotherapy use in this demographic. Patients and Methods: A retrospective study was conducted using electronic medical records of 73 patients with HNSCC who were deemed unsuitable for curative therapy. Palliative radiotherapy involved a uniform dose of 30 Gy in 10 fractions. Survival analysis was performed using Kaplan-Meier method, and multivariate analysis identified significant prognostic factors. Results: The median overall survival was 7.5 months, with no significant difference between age groups. Karnofsky performance status (KPS) >70 correlated with favorable survival. Multivariate analysis confirmed KPS as an independent prognostic factor (hazard ratio=1.949, p=0.031). Conclusion: The results of this study align with those of previous studies, emphasizing the importance of palliative radiotherapy for HNSCC treatment. Optimal dose fractionation regimens remain undetermined, and tailored approaches that consider factors, such as age and performance status are crucial. Individualized, comprehensive assessments and supportive care measures enhance patient well-being, reflecting palliative care principles.

Intrafractional Diaphragm Variations During Breath-Hold Stereotactic Body Radiotherapy for a Liver Tumor Based on Real-Time Registration Between Kilovoltage Projection Streaming and Digitally Reconstructed Radiograph Images: A Case Report.

In liver stereotactic body radiotherapy (SBRT), precise image guidance is paramount, serving as the foundation of this treatment approach. The accuracy of SBRT in liver cancer treatment heavily relies on meticulous imaging techniques. The diaphragm, situated adjacent to the liver, is a crucial anatomical structure susceptible to positional and motion variations, which can potentially impact the accuracy of liver tumor targeting. This study explores the application of real-time kilovoltage projection streaming images (KVPSI) in comparison to digitally reconstructed radiography (DRR) for assessing diaphragm position deviations during breath-hold liver tumor SBRT. A 76-year-old male diagnosed with cholangiocarcinoma underwent breath-hold SBRT using split arc volumetric modulated arc therapy (VMAT), where a full arc was split into six sub-arcs, each spanning 60 degrees. The diaphragm dome positions were continuously monitored through KVPSI during treatment. The intrafractional position deviations of the diaphragm were calculated and analyzed for each split arc. The case report revealed a mean diaphragm dome deviation of 0.47 mm (standard deviation: 4.47 mm) in the entire arc. This pioneering study showcases the feasibility of intrafractional diaphragm position variation assessment using real-time KVPSI during the breath-hold liver tumor VMAT-SBRT. Integrating real-time imaging techniques enhances our comprehension of the intra-breath-hold variations, thereby guiding adaptive treatment strategies and potentially improving treatment outcomes. Clinical validation through further research is essential.

Failure Patterns of Recurrence in Patients With Localized Esthesioneuroblastoma Following Surgery and Adjuvant Radiotherapy Without Elective Nodal Irradiation.

BACKGROUND: Esthesioneuroblastoma (ENB), a rare malignancy arising from the olfactory epithelium, poses clinical challenges owing to its propensity for local invasion and recurrence. Its management typically involves surgical resection and adjuvant radiotherapy. However, debate persists regarding the optimal treatment strategy, particularly the use of elective nodal irradiation (ENI). This study aimed to investigate recurrence patterns in patients with localized ENB treated with surgery and adjuvant radiotherapy without ENI. METHODS: Our retrospective analysis included patients who underwent surgery followed by adjuvant radiotherapy for treatment of ENB between January 2011 and November 2022. Patients with incomplete data or who had received neoadjuvant radiotherapy were excluded. Patient characteristics, radiotherapy data (type, dose, and duration), and follow-up data were collected. Recurrence patterns were evaluated, and overall survival (OS), disease-free survival (DFS), and local control rates were determined using the Kaplan-Meier method. RESULTS: Twelve patients with ENB (median age, 56 years) were included. Most had stage C disease. The median radiation dose was 60 Gy, and the median treatment duration was six weeks. Only one death was confirmed during the observation period, and the five-year DFS rates were 64.3%. Local control was achieved in 11 patients, with only one experiencing local recurrence. Regional lymph node recurrence occurred in three patients and was successfully managed via neck dissection. The timing of recurrence varied, emphasizing the importance of long-term surveillance. CONCLUSION: Adjuvant radiotherapy without ENI is a viable treatment option for ENB, resulting in favorable local control and OS outcomes. Regional lymph node metastases were observed but effectively managed via salvage therapy. Prospective studies with larger cohorts are warranted to confirm the effectiveness of this treatment strategy and to define optimal radiotherapy fields.

Thirty-day Mortality in Palliative Radiotherapy: A Retrospective Cohort Analysis in a Single Center.

Background/Aim: Palliative radiotherapy is a critical component of cancer care aimed at symptom management and enhancing the quality of life of patients with advanced cancer. Balancing symptom relief and potential risks is pivotal in clinical decision-making. This study explored the 30-day mortality (30-DM) rate after palliative radiotherapy in a single-center setting to shed light on potential prognostic factors and safety considerations. Patients and Methods: This retrospective cohort study included patients who underwent palliative radiotherapy for various indications between March 2020 and February 2023. Data were retrieved from electronic medical records and analyzed according to ethical guidelines. The primary outcome measure was 30-DM rate, and multivariate logistic regression analysis was conducted to identify the independent predictors of 30-DM. Results: A total of 931 palliative radiotherapy sessions were administered to 601 patients, with a median of one session per patient. The cohort had a median age of 70 years, predominantly men (58%), and featured diverse primary cancer types, with lung cancer being the most prevalent (15.8%). The 30-DM rate was 12.9%. Multivariate analysis identified Karnofsky Performance Status (KPS) as the sole independent prognostic factor significantly associated with 30-DM. Conclusion: This study provides valuable insights into 30-DM rates following palliative radiotherapy. Future research should focus on prospective multicenter investigations with larger cohorts and comprehensive data collection, ultimately leading to improved risk prediction models for personalized treatment decisions in palliative radiotherapy.

Dual-energy computed tomography-based iodine concentration as a predictor of histopathological response to preoperative chemoradiotherapy for pancreatic cancer.

To explore predictors of the histopathological response to preoperative chemoradiotherapy (CRT) in patients with pancreatic cancer (PC) using dual-energy computed tomography-reconstructed images. This retrospective study divided 40 patients who had undergone preoperative CRT (50-60 Gy in 25 fractions) followed by surgical resection into two groups: the response group (Grades II, III and IV, evaluated from surgical specimens) and the nonresponse group (Grades Ia and Ib). The computed tomography number [in Hounsfield units (HUs)] and iodine concentration (IC) were measured at the locations of the aorta, PC and pancreatic parenchyma (PP) in the contrast-enhanced 4D dual-energy computed tomography images. Logistic regression analysis was performed to identify predictors of histopathological response. Univariate analysis did not reveal a significant relation between any parameter and patient characteristics or dosimetric parameters of the treatment plan. The HU and IC values in PP and the differences in HU and IC between the PP and PC (ΔHU and ΔIC, respectively) were significant predictors for distinguishing the response (n = 24) and nonresponse (n = 16) groups (P < 0.05). The IC in PP and ΔIC had a higher area under curve values [0.797 (95% confidence interval, 0.659-0.935) and 0.789 (0.650-0.928), respectively] than HU in PP and ΔHU [0.734 (0.580-0.889) and 0.721 (0.562-0.881), respectively]. The IC value could potentially be used for predicting the histopathological response in patients who have undergone preoperative CRT.

Retrospective comparison between definitive stereotactic body radiotherapy and radical surgery for 538 patients with early-stage non-small cell lung cancer in a single institution.

Introduction: Survival information for stereotactic body radiotherapy (SBRT) and surgery for stage I non-small cell lung cancer (NSCLC) was examined. Methods: Stage I NSCLC patients who underwent surgery or SBRT between 2012 and 2016 were retrospectively enrolled in this single-institution study. Using the Kaplan--Meier method and Cox regression model, overall survival (OS) was estimated and compared. Results: Among 538 enrolled patients, compared to the surgery group (443), the SBRT group (95) had more complications (P = 0.01), worse performance status (P = 0.001), and were older (P < 0.001). Three-year OS was 70.5% post SBRT and 90.1% postsurgery. The 3-year cancer-specific survival (CSS) and disease-free survival (DFS) post SBRT and postsurgery were 92.7% vs. 92.3% and 61.1% vs 79.3%, respectively. Three-year locoregional and distant control rates post SBRT and postsurgery were 85.6% vs. 90.1% and 82.5% vs. 86.4%, respectively. Multivariate analysis using the Cox model, including age, T-stage, CCI, and C/T ratio and treatment, showed the surgery group's OS to be significantly superior to that of the SBRT group (HR of SBRT per surgery: 1.90, 95%CI: 1.12-3.21, P = 0.017). No significant differences were observed in rates of adverse events. Conclusion: Although OS was better in the surgery group, no differences in CSS existed. This analysis suggests the need for future studies that compare specific radical surgeries and SBRT in a prospective and randomized setting.

Novel breath-hold liver target stereotactic ablative radiotherapy using the intrafraction diaphragm registration of kilovoltage projection streaming image with digitally reconstructed radiography of the planning computed tomography.

Stereotactic ablative radiotherapy (SABR) is an emerging treatment option for patients with primary or metastatic liver tumors, particularly for those who are not eligible for surgery or transplantation. SABR is a high-precision radiation therapy that delivers a high dose of radiation to the tumor while minimizing the dose to the surrounding healthy tissues. However, the accurate targeting of the tumor is a crucial aspect of liver SABR, which requires real-time imaging and tracking of the liver and tumor motion during treatment. One of the motion management strategies for liver SABR is the repeated breath-hold technique, which involves the patient holding their breath multiple times during treatment delivery to reduce the movement of the liver and other organs due to breathing. This technique helps to improve the accuracy of the treatment and reduce the radiation dose to the healthy liver. The current study proposes a novel approach for multiple breath-hold volumetric modulated arc therapy (VMAT) stereotactic ablative radiotherapy for liver tumors, which uses the intrafraction diaphragm registration in real time to improve the accuracy and precision of the treatment. The proposed approach is based on real-time comparison of the diaphragmatic surface location between the digitally reconstructed radiography (DRR) and intrafraction kilovoltage projection streaming images (kV-PSI) having the same beam angles. The image cross-correlation between the DRR and the intrafraction kV-PSI provides a measure of the similarity between the two images and can be used to identify and track the diaphragm position during VMAT delivery. The proposed methodology consists of several steps, including planning CT and treatment planning, reference image reconstruction, and patient positioning and immobilization. The proposed approach has the potential to improve the accuracy and precision of liver cancer VMAT SABR, thereby increasing the efficacy of the treatment and reducing the risk of radiation exposure to surrounding healthy tissues.

Intractable Pleural Effusion After Stereotactic Ablative Radiotherapy for Early-Stage Lung Cancer.

Stereotactic ablative radiotherapy (SABR) is an effective and attractive treatment option for patients who are poor surgical candidates. This case report describes a rare but serious complication of intractable pleural effusion after SABR for early-stage lung cancer. The patient was an 89-year-old woman with a medical history of early-stage breast cancer who was treated with partial resection and postoperative radiotherapy of 50 gray (Gy) in 25 fractions. SABR using 55 Gy in four fractions was conducted for lung lesions. The patient developed a pleural effusion that was refractory to conservative management and required multiple interventions, including repeated thoracentesis. This case report emphasizes the importance of monitoring and managing pleural effusion in patients with lung cancer receiving radiotherapy.

[A report of five cancer screening rates and the related measures for cancer control in the workplace, surveyed by the Corporate Action to Promote Cancer Control].

OBJECTIVES: Most cancer control measures in the workplace have limited supporting evidence. This study aimed to identify highly effective cancer control measures, based on a survey by the Corporate Action to Promote Cancer Control. METHODS: The firms and organizations that responded to the web survey were included. The questionnaire comprised five cancer (stomach, lung, colorectal, breast, and cervical) screening rates and their countermeasures to promote cancer control. We conducted a non-hierarchical cluster analysis according to the degree of the measures and compared the screening rates among each group using an analysis of variance. Then, we performed two multiple regression analyses with the mean screening rates for stomach/lung/colorectal cancer and breast/cervical cancer as dependent variables, the implementation of each countermeasure as an independent variable, and the size and industry as control variables. RESULTS: We obtained responses from 704 firms and organizations. The three groups classified by cluster analysis were defined as active, moderate, and negative. For all cancer screenings, the main effects were significant, and multiple comparisons revealed that the difference between the active and negative groups (ts > 3.30, ps < .01, Hedges' ds > 0.73) and the moderate and negative groups (ts > 3.70, ps < .01, Hedges' ds > 0.88) were significant. For the four cancers other than lung, the difference between the active and moderate groups was not significant (ts < 0.21, ps < .84, Hedges' ds < 0.02), and for lung, the difference was significant, but the effect size was small. The multiple regression analyses revealed that "distribution of colorectal cancer test kits to all subjects" (ß = 0.14) was significant for stomach, lung, and colorectal cancer, while "financial supports for cancer screening" (ß = 0.24), "screening as part of employment" (ß = 0.18), and "careful screening of female subjects" (ß = 0.17) were significant for breast and cervical cancer, respectively. CONCLUSIONS: We identified effective countermeasures for cancer control in the workplace, and these measures will help increase cancer screening rates.

Development of Japanese Cancer Intelligence Quotient to Measure Cancer Literacy and Knowledge among Japanese Laypersons.

Introduction: Health literacy has been identified an essential factor in leading a healthy lifestyle. Because some cancer prevention and screening methods have been established, we believe that identifying disadvantaged populations with low literacy regarding cancer is crucial. Thus, in this study, we aim to create a self-administered cancer-specific health literacy scale to be administered to Japanese laypersons. Methods: Using definitions from previous studies, we constructed a scale named the Japanese Cancer Intelligence Quotient (JCIQ) for both literacy (JCIQ-L) and knowledge (JCIQ-K) aspects. We generated potential items for both aspects, extracted appropriate ones using two-step online surveys, and compared the JCIQ and cancer-preventive behaviors and cancer-screening intentions, both of which we set as alternative indicators of the right attitude and practice toward cancer by performing a multiple regression analysis from another web survey. Results: Between April and May 2020, we conducted three-step surveys online. After conducting the two-step surveys for thousands of people, we extracted 12 literacy questions and 22 knowledge questions using factor analysis and the correct answer ratio of every item. In the final investigation of 3,094 people, a multiple regression analysis found that the JCIQ-L and JCIQ-K were significant factors in terms of predicting both behaviors (JCIQ-L:ß = 0.07, p < 0.001, JCIQ-K:ß = 0.05, p < 0.01) and willingness (JCIQ-L:ß = 0.04, p < 0.05, JCIQ-K:ß = 0.17, p < 0.001) after adjusting for participant characteristics (e.g., gender, age, income level, employment status). Conclusions: We developed the first reliable scale for measuring cancer literacy and knowledge of Japanese laypersons.

Delayed Onset of Pleural Effusion After Thoracic Radiation Therapy for Hodgkin Lymphoma: A Case Report With Over 30-Year Follow-Up.

Pleural effusion after thoracic radiation therapy is an important adverse event affecting the patient's quality of life. A 58-year-old woman was referred to our hospital with the complaint of exertional dyspnea for several months. Chest radiography revealed left pleural effusion, most likely related to radiotherapy to mediastinal and left cervical lymph nodes in the treatment of localized Hodgkin lymphoma 25 years ago. She was followed for the next eight years and experienced a slow exacerbation of pleural effusion. Here, we report a case of extremely late-onset pleural effusion after thoracic radiotherapy.

Effect of employers' concerns about cancer countermeasures on the implementation of cancer screening and support for balancing cancer treatment and work in small and medium-sized Japanese enterprises.

OBJECTIVE: Japan has recently implemented screening and support to balance cancer treatment and work. The present study evaluated whether the interest of employers in small and medium-sized enterprises (SMEs) affects cancer control in the workplace. METHODS: Cancer preparedness at work was examined by a Japanese life insurance company contracting 370 000 SMEs. The analysis targeted SMEs hiring ≤50 employees whose employer was aged ≥40 years. The endpoints were performing one or more screening for stomach, colon, or lung cancer recommended for both sexes in Japan and implementing three or more supportive measures from the nine systems listed in a questionnaire. Logistic regression analysis was performed to predict these endpoints using other factors. RESULTS: The survey was completed from January 5 to 28, 2022 and included 5268 eligible companies. Around half were small enterprises with up to five employees. Screenings were performed for stomach (32%), colorectal (27%), and lung (26%) cancers. Sick leave (36%) was the most common support for balancing cancer treatment and work. Logistic regression analysis revealed that employer's concern was a significant predictor of screening (odds ratio [OR] = 3.59, P < .001) and support (OR = 2.55, P < .01) compared with "not concerned at all," along with industry type, annual sales, experience of employees with cancer, and employer's participation in screening. CONCLUSION: Our findings suggested that employers' interest was a powerful predictor of implementing cancer control in SMEs. Educational intervention targeted toward the employer could play a critical role in improving SMEs.