Assessment and mitigation of radiation hazard for individuals engaged in reconnaissance survey in uranium exploration in Jharkhand, India.

The present study attempts to obtain an a priori estimate of the absorbed dose received by an individual engaged in the reconnaissance survey in Uranium exploration using a predictive mathematical regression analysis. Other radiation safety parameters such as excess lifetime cancer risk are also calculated. Study reflects that the proper handling of naturally occurring radioactive materials accounts for an absorbed dose significantly less than the prescribed limit.

The impact of baseline health factors on second primary cancer risk after radiotherapy for prostate cancer.

PURPOSE: In evaluating second primary cancers (SPCs) following External Beam Radiotherapy (EBRT), the role of lifestyle factors is frequently not considered due to data limitations. We investigated the association between smoking, comorbidities, and SPC risks within EBRT-treated patients for localized prostate cancer (PCa). PATIENTS & METHODS: The study included 1,883 PCa survivors aged 50-79, treated between 2006 and 2013, with intensity-modulated radiotherapy (IMRT) or three-dimensional conformal radiotherapy (3D-CRT). Clinical data were combined with SPC and survival data from the Netherlands Cancer Registry with a 12-month latency period. Standardized Incidence Ratios (SIRs) were calculated comparing the EBRT cohort with the general Dutch population. To explore the effect of patient and treatment characteristics on SPCs we conducted a Cox regression analysis. Lastly, we estimated cumulative incidences of developing solid SPC, pelvis SPC, and non-pelvis SPC using a competing risk analysis. RESULTS: Significantly increased SIRs were observed for all SPC (SIR = 1.21, 95% confidence interval [CI]: 1.08-1.34), pelvis SPC (SIR = 1.46, 95% CI: 1.18-1.78), and non-pelvis SPC (SIR = 1.18, 95% CI [1.04-1.34]). Smoking status was significantly associated with pelvic and non-pelvic SPCs. Charlson comorbidity index (CCI) ≥ 1 (Hazard Ratio [HR] = 1.45, 95% CI: 1.10-1.91), cardiovascular disease (HR = 1.41, 95% CI: 1.05-1.88), and chronic obstructive pulmonary disease (COPD) (HR = 1.91, 95% CI: 1.30-2.79) were significantly associated with non-pelvis SPC. The proportion of active smoking numbers in the cohort was similar to the general population. INTERPRETATION: We conclude that the presence of comorbidities in the EBRT population might be a relevant factor in observed excess non-pelvis SPC risk, but not for excess pelvis SPC risk.

Low-dose radiation therapy for COVID-19 pneumonia: Comparison of dosimetry and life-time attributable risk of cancer with conventional AP-PA fields and bone marrow sparing VMAT.

PURPOSE: Low-dose radiation therapy (LDRT) to lungs did show encouraging results in COVID-19 patients in some clinical trials. However, there has been some concern regarding the long-term risk of radiation-induced cancer (RIC). Compared to the conventional AP-PA field technique, volumetric modulated arc therapy (VMAT) can potentially reduce the dose to the marrow and other organs at risk (OARs) and thus minimize the risk of cancer. We designed a dosimetry study to study if VMAT can reduce the exposure to the marrow and other OAR doses and curtail the estimated life-time attributable risk (LAR) of cancer. METHODS AND MATERIALS: We retrieved the computed tomography scan data of 10 patients (aged 40-60 years, median 48 years) who have been already treated for any malignancy in the region of the thorax. A dose of 1.0 Gy in single fraction was prescribed to both lungs. All the organs were delineated as per the established guidelines. The dosimetry achieved by the two plans was compared to find the difference. Mean OAR doses were used to estimate the LAR for both plans and compared. RESULTS: Planning target volume coverage parameters like conformity index and homogeneity index were significantly better with VMAT (P value < 0.05 for all). The mean dose to most OARs was significantly lower with VMAT (P value < 0.05 for all). The mean dose to the marrow was significantly lower with VMAT (59.05 vs 81.9 cGy with P value < 0.05). The overall LAR was significantly lower with VMAT as compared to the conventional plan (0.357% vs 0.398%, P value < 0.05). CONCLUSION: Compared to the conventional technique, VMAT provides better OAR dosimetry for lung irradiation (a prescription dose of 1.0 Gy or more) in COVID-19 pneumonia. VMAT significantly reduces the risk of RIC. We therefore suggest if lung LDRT is used for COVID-19 patients, VMAT is the preferred technique for a prescription dose of ≥1.0 Gy.

Incidence risk of hepatobiliary malignant neoplasms in the cohort of workers chronically exposed to ionizing radiation.

The increased risk of liver malignancies was found in workers of the first Russian nuclear production facility, Mayak Production Association, who had been chronically exposed to gamma rays externally and to alpha particles internally due to plutonium inhalation. In the present study, we updated the radiogenic risk estimates of the hepatobiliary malignancies using the extended follow-up period (1948-2018) of the Mayak worker cohort and the improved «Mayak worker dosimetry system-2013¼. The cohort comprised 22,377 workers hired at the Mayak PA between 1948 and 1982. The analysis considered 62 liver malignancies (32 hepatocellular carcinomas, 13 intrahepatic cholangiocarcinomas, 16 angiosarcomas, and 1 anaplastic cancer) and 33 gallbladder adenocarcinomas. The analysis proved the positive significant association of the liver malignancy risk (the total of histological types, hepatocellular carcinoma) with the liver absorbed alpha dose from internal exposure. The excess relative risk per Gy (95% confidence interval) of alpha dose (the linear model) was 7.56 (3.44; 17.63) for the total of histological types and 3.85 (0.95; 13.30) for hepatocellular carcinoma. Indications of non-linearity were observed in the dose-response for internal exposure to alpha radiation. No impact of external gamma-ray exposure on the liver malignancy incidence was found. In the study cohort, the number of angiosarcomas among various types of liver malignancies was very high (25.8%), and most of these tumors (73.3%) were registered in individuals internally exposed to alpha radiation at doses ranging between 6.0 and 21.0 Gy. No association with chronic occupational radiation exposure was observed for the incidence of gallbladder malignancies.

Cosmic Ionizing Radiation: A DNA Damaging Agent That May Underly Excess Cancer in Flight Crews.

In the United States, the Federal Aviation Administration has officially classified flight crews (FC) consisting of commercial pilots, cabin crew, or flight attendants as "radiation workers" since 1994 due to the potential for cosmic ionizing radiation (CIR) exposure at cruising altitudes originating from solar activity and galactic sources. Several epidemiological studies have documented elevated incidence and mortality for several cancers in FC, but it has not yet been possible to establish whether this is attributable to CIR. CIR and its constituents are known to cause a myriad of DNA lesions, which can lead to carcinogenesis unless DNA repair mechanisms remove them. But critical knowledge gaps exist with regard to the dosimetry of CIR, the role of other genotoxic exposures among FC, and whether possible biological mechanisms underlying higher cancer rates observed in FC exist. This review summarizes our understanding of the role of DNA damage and repair responses relevant to exposure to CIR in FC. We aimed to stimulate new research directions and provide information that will be useful for guiding regulatory, public health, and medical decision-making to protect and mitigate the risks for those who travel by air.

[Radiation-induced sarcoma in patients with nasopharyngeal carcinoma: a single-institution retrospective study].

Objective:To analyze the clinical features, treatment methods and prognosis of radiation-induced sarcoma（RIS） of the head and neck after radiotherapy for nasopharyngeal carcinoma（NPC）, and explore its treatment strategies. Methods:A retrospective analysis was conducted on RIS patients after radiotherapy for NPC in the People's Hospital of Guangxi Zhuang Autonomous Region from January 2013 to October 2022. The time of onset, lesion location, pathological subtypes, imaging features and treatment outcomes were described, and the median survival time was statistically analyzed through follow-up. Results:This study included 10 patients with an interval of 2-27 years between NPC and RIS. The nasopharynx was the more common site of RIS, and osteosarcoma was the main pathological type. The median overall survival was 18 months. The median survival was 40 months in the surgery combined with the chemotherapy group, and 12 months in the surgery alone group. The 1-and 2-year cumulative survival rates were 48% and 36%, respectively. Prognostic analysis showed that gender, age of onset, time of sarcoma onset after radiotherapy and treatment methods might not be influencing factors for prognosis, and osteosarcomas presented a poorer prognosis than other pathological types. Conclusion:RIS is one of the most severe long-term adverse effects in patients with NPC. The prognosis of RIS is poor, and complete surgical resection of the tumor can improve patient survival rates. In cases where complete surgical resection is challenging, radiotherapy or chemotherapy may offer some improvement in tumor control.

[Does radiation therapy for prostate cancer increase the risk of second cancers?] / La radiothérapie du cancer de la prostate augmente-t-elle le risque de seconds cancers ?

PURPOSE: The increased risk of second cancer after prostate radiotherapy is a debated clinical concern. The objective of the study was to assess the risk of occurrence of second cancers after prostate radiation therapy based on the analysis the literature, and to identify potential factors explaining the discrepancies in results between studies. MATERIALS AND METHODS: A review of the literature was carried out, comparing the occurrence of second cancers in patients all presenting with prostate cancer, treated or not by radiation. RESULTS: This review included 30 studies reporting the occurrence of second cancers in 2,112,000 patients treated or monitored for localized prostate cancer, including 1,111,000 by external radiation therapy and 103,000 by brachytherapy. Regarding external radiation therapy, the average follow-up was 7.3years. The majority of studies (80%) involving external radiation therapy, compared to no external radiation therapy, showed an increased risk of second cancers with a hazard ratio ranging from 1.13 to 4.9, depending on the duration of the follow-up. The median time to the occurrence of these second cancers after external radiotherapy ranged from 4 to 6years. An increased risk of second rectal and bladder cancer was observed in 52% and 85% of the studies, respectively. Considering a censoring period of more than 10 years after irradiation, 57% and 100% of the studies found an increased risk of rectal and bladder cancer, without any impact in overall survival. Studies of brachytherapy did not show an increased risk of second cancer. However, these comparative studies, most often old and retrospective, had many methodological biases. CONCLUSION: Despite numerous methodological biases, prostate external radiation therapy appears associated with a moderate increase in the risk of second pelvic cancer, in particular bladder cancer, without impacting survival. Brachytherapy does not increase the risk of a second cancer.

Assessment of radiation exposure risks in patients undergoing elastic stable intramedullary nailing: Insights from intraoperative fluoroscopy.

INTRODUCTION: Elastic stable intramedullary nailing (ESIN) is a well-defined and appropriate treatment of choice for long bone fractures. Despite its benefits, the risk of cancer from imaging devices is of particular concern for younger adults. So, this survey was conducted to estimate the doses administered to patients undergoing ESIN of long bone fractures utilizing a 2-dimensional (2D) C-arm fluoroscopy machine during surgery, as well as the carcinogenic risk associated with the use of the machine. METHODS: This study was conducted on 147 patients who required ESIN for long-bone fractures. Patients' demographic data, surgical data and imaging information were collected. For each patient, the organ doses and the effective doses were computed with the Monte Carlo PCXMC 2.0 simulation software. The cancer risk models proposed in the Biological Effects of Ionizing Radiation VII (BEIR VII) Phase 2 report were used to evaluate the risk of exposure-induced cancer death (REID) values. RESULTS: For all patients, the highest organ dose was delivered to the gonads. The mean effective dose was 0.026 ± 0.015 mSv and 1.3E-04 ± 1E-04 mSv for ESIN of femur and tibia fractures, respectively. Males had a mean REID of 1 per million, while females had a mean REID of 0.19 per million. The younger males had considerably higher REID values. The effective dose was significantly correlated with age, gender, and irradiation time. CONCLUSION: Low levels of effective doses and cancer risks associated with the utilization of the fluoroscopy machine in current practice were found in ESIN treatment of long-bone fractures. IMPLICATIONS FOR PRACTICE: This outcome will help to raise surgeons' awareness of radiation risks and encourage them to initiate measures to keep radiation dose and exposure time as low as reasonably achievable.

Outcomes of non-angiosarcoma radiation-associated soft tissue sarcomas of the chest.

BACKGROUND: Radiation-associated soft tissue sarcomas (RA-STS) are rare complications of patients receiving radiation therapy (RT) and are generally associated with a poor prognosis. Most of the literature surrounding RA-STS of the chest is centered on angiosarcoma. Therefore, we aim to document the management and outcome of patients with non-angiosarcoma RA-STS of the chest. METHODS: We reviewed 17 patients (all female, median age 65 years) diagnosed with RA-STS. The most common primary malignancy was breast carcinoma (n = 15), with a median RT dose of 57.9 Gy. All patients underwent surgical resection; five patients (29%) received radiotherapy; and five patients (29%) received peri-operative chemotherapy. RESULTS: The 5-year local recurrence and metastatic-free survival were 61% and 60%, while the 5-year disease-specific survival was 53%. Local recurrence was associated with death due to disease (HR 9.06, p = 0.01). Complications occurred in nine of patients, most commonly due to a wound complication (n = 7). At the most recent follow-up, the median Musculoskeletal Tumor Society Score was 63%. CONCLUSION: RA-STS involving the chest wall are aggressive tumors with a high risk of local relapse and death due to disease. Local recurrence was associated with death due to disease; as such, we recommend aggressive surgical management with evaluation for adjuvant therapies.

Outcome improvement with chemotherapy and radiotherapy in primary, localized, radiation-associated angiosarcoma of the breast region: a retrospective case series analysis.

BACKGROUND: We report on a series of consecutive patients with localized radiation-associated angiosarcoma (RAAS) of the breast region (BR) treated at two Italian sarcoma reference centers. MATERIALS AND METHODS: We retrospectively reviewed all cases of primary, localized, resectable RAAS of the BR, treated at one of the two participating institutions from 2000 to 2019. Relapse-free survival (RFS) and overall survival (OS) were calculated. The prognostic role of several variables was investigated. A propensity score matched (PSM) analysis was carried out. RESULTS: Eighty-four patients were retrospectively identified. Nineteen out of 84 patients (22.6%) were pretreated with an anthracycline-based regimen for previous cancer. All patients but one underwent surgery, with 37/84 (44.1%) receiving surgery alone and 46/84 (54.8%) a multimodal approach: 18/84 (21.4%) received radiation therapy (RT) and 46/84 (54.9%) received chemotherapy. An anthracycline-based regimen was used in 10/84 patients (11.9%), while a gemcitabine-based regimen was used in 33/84 (39.3%). With a median follow-up of 51 months (interquartile range: 30-126 months), 36/84 patients (42.9%) relapsed and 35/84 patients (41.7%) died (8/84, 9.5% in the lack of metastatic disease). Five-year OS and 5-year RFS were 57% [95% confidence interval (CI) 43% to 68%] and 52% (95% CI 39% to 63%), respectively. Both (neo)adjuvant RT and chemotherapy were associated with better RFS [hazard ratio (HR) 0.25, 95% CI 0.08-0.83; HR 0.45, 95% CI 0.23-0.89] with a trend towards a better OS (HR 0.51, 95% CI 0.18-1.46; HR 0.60, 95% CI 0.29-1.24). Gemcitabine-based regimens seemed to perform better (HR 4.28, 95% CI 1.29-14.14). PSM analysis retained the above results. CONCLUSIONS: This retrospective study supports the use of (neo)adjuvant RT and chemotherapy, in primary, localized resectable RAAS of the BR. An effort to prospectively validate the role of (neo)adjuvant RT and chemotherapy is warranted.

Secondary cancer risk assessment in healthy organs following craniospinal irradiation.

INTRODUCTION: Medulloblastoma is a central nerves tumor that often occurs in pediatrics. The main radiotherapy technique for this tumor type is craniospinal irradiation (CSI), through which the whole brain and spinal cord are exposed to radiation. Due to the immaturity of healthy organs in pediatrics, radiogenic side effects such as second cancer are more severe. Accordingly, the current study aimed to evaluate the risk of secondary cancer development in healthy organs following CSI. MATERIALS AND METHODS: Seven organs at risk (OARs) including skin, eye lens, thyroid, lung, liver, stomach, bladder, colon, and gonads were considered and the dose received by each OAR during CSI was measured inside an anthropomorphic RANDO phantom by TLDs. Then, the mean obtained dose for each organ was used to estimate the probability of secondary malignancy development according to the recommended cancer risk coefficients for specific organs. RESULTS: The results demonstrated that the stomach and colon are at high risk of secondary malignancy occurrence, while the skin has the lowest probability of secondary cancer development. The total received dose after the treatment course by all considered organs was lower than the corresponding tolerable dose levels. CONCLUSIONS: From the results, it can be concluded that some OARs during CSI are highly at risk of secondary cancer development. This issue may be of concern due to organ immaturity in pediatrics which can intensify the radiogenic effects of radiation exposure. Accordingly, strict shielding the OARs during craniospinal radiotherapy and/or sparing them from the radiation field through modern techniques such as hadron therapy is highly recommended.

Risk and prognosis of secondary lung cancer after radiation therapy for thoracic malignancies.

OBJECTIVE: Radiation therapy (RT) may increase the risk of second cancer. This study aimed to determine the association between exposure to radiotherapy for the treatment of thoracic cancer (TC) and subsequent secondary lung cancer (SLC). MATERIALS AND METHODS: The Surveillance, Epidemiology, and End Results (SEER) database (from 1975 to 2015) was queried for TC. Univariate Cox regression analyses and multiple primary standardized incidence ratios (SIRs) were used to assess the risk of SLC. Subgroup analyses of patients stratified by latency time since TC diagnosis, age at TC diagnosis, and calendar year of TC diagnosis stage were also performed. Overall survival and SLC-related death were compared among the RT and no radiation therapy (NRT) groups by using Kaplan-Meier analysis and competitive risk analysis. RESULTS: In a total of 329 129 observations, 147 847 of whom had been treated with RT. And 6799 patients developed SLC. Receiving radiotherapy was related to a higher risk of developing SLC for TC patients (adjusted HR, 1.25; 95% CI, 1.19-1.32; P < 0.001). The cumulative incidence of developing SLC in TC patients with RT (3.8%) was higher than the cumulative incidence (2.9%) in TC patients with NRT(P). The incidence risk of SLC in TC patients who received radiotherapy was significantly higher than the US general population (SIR, 1.19; 95% CI, 1.14-1.23; P < 0.050). CONCLUSIONS: Radiotherapy for TC was associated with higher risks of developing SLC compared with patients unexposed to radiotherapy.

Radiation Dose-Volume-Response Relationships for Adverse Events in Childhood Cancer Survivors: Introduction to the Scientific Issues in PENTEC.

At its very core, radiation oncology involves a trade-off between the benefits and risks of exposing tumors and normal tissue to relatively high doses of ionizing radiation. This trade-off is particularly critical in childhood cancer survivors (CCS), in whom both benefits and risks can be hugely consequential due to the long life expectancy if the primary cancer is controlled. Estimating the normal tissue-related risks of a specific radiation therapy plan in an individual patient relies on predictive mathematical modeling of empirical data on adverse events. The Pediatric Normal-Tissue Effects in the Clinic (PENTEC) collaborative network was formed to summarize and, when possible, to synthesize dose-volume-response relationships for a range of adverse events incident in CCS based on the literature. Normal-tissue clinical radiation biology in children is particularly challenging for many reasons: (1) Childhood malignancies are relatively uncommon-constituting approximately 1% of new incident cancers in the United States-and biologically heterogeneous, leading to many small series in the literature and large variability within and between series. This creates challenges in synthesizing data across series. (2) CCS are at an elevated risk for a range of adverse health events that are not specific to radiation therapy. Thus, excess relative or absolute risk compared with a reference population becomes the appropriate metric. (3) Various study designs and quantities to express risk are found in the literature, and these are summarized. (4) Adverse effects in CCS often occur 30, 50, or more years after therapy. This limits the information content of series with even very extended follow-up, and lifetime risk estimates are typically extrapolations that become dependent on the mathematical model used. (5) The long latent period means that retrospective dosimetry is required, as individual computed tomography-based radiation therapy plans gradually became available after 1980. (6) Many individual patient-level factors affect outcomes, including age at exposure, attained age, lifestyle exposures, health behaviors, other treatment modalities, dose, fractionation, and dose distribution. (7) Prospective databases with individual patient-level data and radiation dosimetry are being built and will facilitate advances in dose-volume-response modeling. We discuss these challenges and attempts to overcome them in the setting of PENTEC.

Skin cancers are the most frequent cancers in fair-skinned populations, but we can prevent them.

Cancers of the skin are the most commonly occurring cancers in humans. In fair-skinned populations, up to 95% of keratinocyte skin cancers and 70-95% of cutaneous melanomas are caused by ultraviolet radiation and are thus theoretically preventable. Currently, however, there is no comprehensive global advice on practical steps to be taken to reduce the toll of skin cancer. To address this gap, an expert working group comprising clinicians and researchers from Africa, America, Asia, Australia, and Europe, together with learned societies (European Association of Dermato-Oncology, Euromelanoma, Euroskin, European Union of Medical Specialists, and the Melanoma World Society) reviewed the extant evidence and issued the following evidence-based recommendations for photoprotection as a strategy to prevent skin cancer. Fair skinned people, especially children, should minimise their exposure to ultraviolet radiation, and are advised to use protective measures when the UV index is forecast to reach 3 or higher. Protective measures include a combination of seeking shade, physical protection (e.g. clothing, hat, sunglasses), and applying broad-spectrum, SPF 30 + sunscreens to uncovered skin. Intentional exposure to solar ultraviolet radiation for the purpose of sunbathing and tanning is considered an unhealthy behaviour and should be avoided. Similarly, use of solaria and other artificial sources of ultraviolet radiation to encourage tanning should be strongly discouraged, through regulation if necessary. Primary prevention of skin cancer has a positive return on investment. We encourage policymakers to communicate these messages to the general public and promote their wider implementation.

Radiation-Associated Vestibular Schwannomas: Case Series and Literature Review.

OBJECTIVES: Radiation treatment, particularly at a young age, creates theoretical risk for long-term adverse radiation effects, including the development of malignancy. The literature is sparse on radiation-induced vestibular schwannomas (VSs). METHODS: A retrospective review was performed for cases of suspected radiation-induced VS at 2 high-volume centers. Only cases where radiation included coverage of the posterior fossa were included with those diagnosed within 3 years of radiation treatment being excluded. Patient and tumor characteristics were collected. A systematic literature review was also performed for any previously published series on radiation-induced VS. RESULTS: Eight cases of radiation-induced VS were identified with a median follow-up 125 months (range 7-131). The median age at incident radiation was 15 years (range 2-46). The median age at VS diagnosis was 57 years (range 26-83) with median interval from radiation to diagnosis of 51-years (range 15-66). The median tumor size was 6 mm (range 3-21). Two patients underwent surgical resection. Lesions were described as soft and highly vascular, with medium to high adherence to the facial nerve. Five articles with a total of 52 patients were identified, median age at VS diagnosis was 42-years (range 23-73) with a median interval from radiation to diagnosis of 19 years (range 15-23). CONCLUSIONS: The development of VS following radiation exposure appears rare and our understanding of the condition remains incomplete. Further studies are required to determine the best management of these patients and determine whether there is a causative relationship between radiation exposure and the development of VS.

Radiation-induced Sarcoma of the Prostate After Treatment for Rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is among the most common pediatric solid malignancies. Fusion-negative, embryonal RMS is the predominant histology among prostate and bladder lesions. Management strategies depend on the clinical stage and risk group. Although the optimal strategy continues to evolve, the field has transitioned from radical upfront resection to organ preservation strategies with multi-modal therapy, including chemotherapy, radiation, and surgery. Survivors frequently develop late complications, including impaired fertility and sexual function, bladder dysfunction, and secondary malignancies. Our case describes an 11-year-old male who developed a radiation-induced prostatic sarcoma. We present a novel surgical technique and highlight the importance of multidisciplinary care.

Carcinogenic risk in patients treated with UVA-1 phototherapy: A 5-year retrospective study.

BACKGROUND: UVA-1 phototherapy was first used to treat atopic dermatitis and afterwards to several other skin diseases. The contribution of UVA-1 in human photocarcinogenesis, skin photoaging, immune suppression, and hyperpigmentation is now well established. The actual contribution of UVA-1 radiation to the development of malignant melanoma (MM) in humans cannot be excluded. PURPOSE: The aim of the study is to evaluate the risk of developing skin cancers (non-melanoma skin cancers (NMSCs) and MM) in patients treated with UVA-1 phototherapy with a 5-year dermatological follow-up. METHODS: We conducted a retrospective cohort study with 31 patients with morphea and atopic dermatitis treated with medium dose UVA-1 phototherapy (34 J/cm2). All enrolled patients underwent an oncologic prevention visit annually with a 5-year follow-up with clinical evaluation of the entire skin surface. RESULTS: During the 5-year follow-up, we recorded a case of basal cell carcinoma (BCC) in the cervical region and one case of MM on the back (pT1a). In both cases, the patients were female and affected by morphea. The Glogau 3 group is prevalent (42%), which is consistent with moderate to severe aging; the data appear to be compatible with the age. CONCLUSIONS: This study attests that medium-dose UVA-1 phototherapy does not increase the risk of developing skin tumors and that UVA-1 phototherapy is not a worsening factor of facial photoaging. The main limitation of the study is the small sample size, avoiding to obtain statistically significant values. It was not possible to analyze individually the actual daily sun exposure during the 5-year observation period and to correlate it in terms of time and tumor development. Further studies with large sample sizes will be needed to confirm our data. Our study reaffirms how the dermatological examination performed annually is essential in the follow-up of patients undergoing this type of therapy.

Efficacy of Combinational Treatment versus Nicotinamide Monotherapy in the Prevention of Ultraviolet Radiation-Induced Skin Cancer.

INTRODUCTION: Ultraviolet radiation (UVR) is the primary risk factor for keratinocyte carcinomas. Oral supplementation with nicotinamide (NAM) is reported to reduce the formation of new keratinocyte carcinomas. NAM's photoprotection is mediated by enhanced DNA repair. We wanted to explore whether NAM in combination with antiproliferative (metformin [Met]) or antioxidant (phloroglucinol [PG]) compounds could potentially enhance its photoprotective effects. METHODS: Hairless mice (C3.Cg-Hrhr/TifBomTac) were treated orally with either a standard dose of NAM monotherapy (NAM-mono; 600 mg/kg) or NAM (400 mg/kg) combined with Met (200 mg/kg) (NAM-Met) or PG (75 mg/kg) (NAM-PG). Mice were irradiated with 3.5 standard erythema doses of UVR three times per week to induce tumour development. Photoprotective effects were based on (i) tumour onset of the first three tumours, (ii) skin photodamage, and (iii) DNA damage (cyclobutane pyrimidine dimers [CPDs] and pyrimidine-pyrimidone (6-4) photoproducts [6-4PPs]). RESULTS: All mice treated with NAM demonstrated a delay in tumour onset and reduced tumour burden compared to the UV control group (NAM, NAM-Met, NAM-PG vs. UV control: p ≤ 0.015). NAM-mono and NAM-PG increased time until all three tumours with no difference between them, indicating a similar degree of photoprotection. NAM-mono had no effect on DNA damage compared to the UV control group (p > 0.05), whereas NAM-PG reduced 6-4PP lesions (p < 0.01) but not CPDs (p > 0.05) compared to NAM-mono. NAM-Met delayed the onset of the third tumour compared to the UV control but demonstrated a quicker onset compared to NAM-mono, suggesting inferior photoprotection compared to nicotinamide monotherapy. CONCLUSION: NAM-PG was as effective in delaying UVR-induced tumour onset as NAM-mono. The reduction in 6-4PP lesions may indicate that the mechanism of NAM-PG is better suited for photoprotection than NAM-mono. NAM-mono was superior to NAM-Met, indicating a dose dependency of NAM's photoprotection. These results highlight the potential for combining photoprotective compounds to enhance photoprotection.

Updated Analysis of Radon Exposure and Lung Cancer Mortality in the Cohort of Newfoundland Fluorspar Miners (1950-2016).

The commercial mining of fluorspar in St. Lawrence Newfoundland began in 1933. Miners who worked underground were exposed to high levels of radon progeny, especially before ventilation was introduced into the mines in 1960. The mean cumulative radon exposure for underground miners in this cohort was 380.9 working level months (WLM). A series of studies of this cohort have characterized the increased risks of lung cancer mortality due to radon. We have extended the follow-up of this cohort an additional 15 years to provide additional insights on the risks of low levels of radon exposure, and the modifying effects of time since exposure, age at first exposure, attained age, duration of exposure, and cigarette smoking. The cohort consisted of 1,735 underground and 315 male surface miners who, combined, accrued 81,650 person-years of follow-up. The mortality experience of the cohort was determined from 1950-2016 through record linkage to Canadian national death data. Individual-level estimates of exposure to radon progeny, in WLMs, were determined for each year of employment. We compared the mortality experience of the underground miners to Newfoundland men using the standardized mortality ratio (SMR). Poisson regression models were fit to estimate excess relative risks (ERR) per 100 WLM. There were 236 lung cancer deaths identified, and of these, 221 occurred among underground workers. The SMR for lung cancer among underground miners compared to Newfoundland men was 2.67 (95% CI: 2.33, 3.04). The ERR per 100 WLM for lung cancer mortality, assuming a 5-year exposure lag, was 0.41 (95% CI: 0.23, 0.59). Attained age and time since exposure were important modifiers to the radon-lung cancer relationship. The joint relationship between smoking and radon on lung cancer risk was sub-additive, however, the smoking data were limited and available for only half of the cohort.