Second primary cancer after treatment for cervical cancer. An international cancer registries study

Reasons why the idea that radiation exposures induce cancer needs to be revisited

PURPOSE

It has long been thought that the carcinogenic effect of radiation resulted from the induction of oncogenic mutations which then led to an increase in the proportion of cancer-bearing individuals. However, even as early as the 1960s, there were indications that the carcinogenic effect of radiation might result from the induction of an earlier onset of cancer. Recently, the former notion was challenged by its inability to explain time-dependent decline of the relative risk following an exposure to radiation, and a parallel shift of mouse survival curves toward younger ages following an exposure to radiation. The two observations are clearly understood if it is assumed only that a radiation exposure causes an earlier onset of spontaneously occurring cancers.

METHOD

In the present study, a critical review was conducted which examined papers that showed dose responses which apparently supported the mutation induction theory of radiation carcinogenesis.

RESULTS

It was found that there were two types of misleading experimental designs: one consisted of studies in which observations were prematurely terminated, and which consequently hid a complete story of radiation carcinogenesis. The other set of papers used age adjustments which were derived from the idea that the life shortening effect of radiation needs to be compensated for since tumor mortality becomes higher among older subjects. This type of adjustment appeared reasonable but was found actually to be a different form of description on an earlier onset of cancer following radiation exposures.

CONCLUSION

In mouse experiments, radiation exposures did not lead to the induction of a large increase in the proportion of tumor deaths when life-long observations were made. Human epidemiologic data are also in line with the earlier onset hypothesis of radiation action. It should be cautioned, however, that the earlier onset model applies only to malignancies whose mortality increases rapidly with the increase of age and does not apply to diseases of short latency such as childhood leukemia and thyroid cancers.

Effect of bolus materials on dose deposition in deep tissues during electron beam radiotherapy

Several materials are utilized in the production of bolus, which is essential for superficial tumor radiotherapy. This research aimed to compare the variations in dose deposition in deep tissues during electron beam radiotherapy when employing different bolus materials. Specifically, the study developed general superficial tumor models (S-T models) and postoperative breast cancer models (P-B models). Each model comprised a bolus made of water, polylactic acid (PLA), polystyrene, silica-gel or glycerol. Geant4 was employed to simulate the transportation of electron beams within the studied models, enabling the acquisition of dose distributions along the central axis of the field. A comparison was conducted to assess the dose distributions in deep tissues. In regions where the percentage depth dose (PDD) decreases rapidly, the relative doses (RDs) in the S-T models with silica-gel bolus exhibited the highest values. Subsequently, RDs for PLA, glycerol and polystyrene boluses followed in descending order. Notably, the RDs for glycerol and polystyrene boluses were consistently below 1. Within the P-B models, RDs for all four bolus materials are consistently below 1. Among them, the smallest RDs are observed with the glycerol bolus, followed by silica-gel, PLA and polystyrene bolus in ascending order. As PDDs are ~1-3% or smaller, the differences in RDs diminish rapidly until are only around 10%. For the S-T and P-B models, polystyrene and glycerol are the most suitable bolus materials, respectively. The choice of appropriate bolus materials, tailored to the specific treatment scenario, holds significant importance in safeguarding deep tissues during radiotherapy.

O Risco Genético das Terapias do Câncer

O presente artigo descreve as conseqüências de algumas terapias utilizadas para o câncer sobre o material genético de pacientes com neoplasias. O objetivo é ressaltar a importância da avaliação da relação risco/ benefício dos diferentes tratamentos utilizados para o câncer, e da continuidade de pesquisas para o desenvolvimento de novas formas de terapia e de novas drogas antineoplásicas. Faremos breve exposição sobre o processo de carcinogênese de múltiplas etapas, destacando o conceito geral de que o câncer é uma doença genética. São apresentados os efeitos mutagênicos das radiações ionizantes e de algumas classes de quimioterápicos sobre o material genético. Além dos efeitos deletérios desses agentes para o paciente, são também relatados efeitos nocivos para os indivíduos que manipulam ou que são responsáveis pela condução dos tratamentos. Abordaremos de modo geral, os danos genéticos induzidos por agentes antineoplásicos mutagênicos tanto para o paciente como para os indivíduos que os manipulam, predispondo-os ao desenvolvimento de um segundo tumor ou de um tumor primário, respectivamente.

Second malignancy probabilities in patients with prostate cancer treated with whole pelvis radiation therapy versus prostate only radiation therapy

BACKGROUND

Whole pelvic radiation therapy (WPRT) may improve outcomes compared with prostate only radiation therapy (PORT) in some subsets of men with prostate cancer, as in the POP-RT trial. However, there is concern about increased risk of adverse effects with WPRT, including the development of radiation-induced second malignancies (SM). Given the rarity of SM, little is known about relative rates of SM between WPRT and PORT.

METHODS

A retrospective cohort analysis was performed of men with nonmetastatic, node-negative prostate cancer with at least 60 months of follow-up using a national database. SM probabilities were compared in men receiving either WPRT or PORT using multivariable logistic models adjusting for clinical and sociodemographic factors. Temporal sensitivity analyses stratified by year of diagnosis and length of follow-up were also conducted.

RESULTS

Of 50,237 patients in the study, 39,338 (78.4%) received PORT, and 10,899 (21.7%) received WPRT. Median follow-up was 106.2 months (interquartile range 82.32-132.25). Crude probabilities of SM were 9.16% for WPRT and 8.88% for PORT. The adjusted odds ratio (AOR) for development of SM with PORT versus WPRT was 1.046 (95% confidence interval 0.968-1.130). Temporal sensitivity analyses by stratifying by year of diagnosis and follow-up length also did not demonstrate any significant difference in rates of SM between WPRT and PORT using AORs with WPRT as the referent.

CONCLUSIONS

Retrospective analysis of over 50,000 patients did not demonstrate an association between WPRT and an increased probability of SM compared to PORT. Given the findings of POP-RT, the use of WPRT may become widespread for certain subsets of men. Thus, our findings could help guide how we counsel patients deciding between WPRT and PORT and suggest the need for prospective assessment of SM risk with WPRT and PORT.

Assessment of Second Primary Cancer Risk Among Men Receiving Primary Radiotherapy vs Surgery for the Treatment of Prostate Cancer

IMPORTANCE

Shared decision-making is an important part of the treatment selection process among patients with prostate cancer. Updated information is needed regarding the long-term incidence and risk of second primary cancer after radiotherapy vs nonradiotherapy treatments, which may help to inform discussions of risks and benefits for men diagnosed with prostate cancer.

OBJECTIVE

To assess the current incidence and risk of developing a second primary cancer after receipt of radiotherapy vs nonradiotherapy treatments for prostate cancer.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used the Veterans Affairs Corporate Data Warehouse to identify 154 514 male veterans 18 years and older who had localized prostate cancer (tumor stages T1-T3) diagnosed between January 1, 2000, and December 31, 2015, and no cancer history. A total of 10 628 patients were excluded because of (1) incomplete treatment information for the year after diagnosis, (2) receipt of both radiotherapy and a surgical procedure in the year after diagnosis, (3) receipt of radiotherapy more than 1 year after diagnosis, (4) occurrence of second primary cancer or death within 1 year or less after diagnosis, (5) prostate-specific antigen value greater than 99 ng/mL within 6 months before diagnosis, or (6) no recorded Veterans Health Administration service after diagnosis. The remaining 143 886 patients included in the study had a median (IQR) follow-up of 9 (6-13) years. Data were analyzed from May 1, 2021, to May 22, 2022.

MAIN OUTCOMES AND MEASURES

Diagnosis of a second primary cancer more than 1 year after prostate cancer diagnosis.

RESULTS

Among 143 886 male veterans (median [IQR] age, 65 [60-71] years) with localized prostate cancer, 750 (0.5%) were American Indian or Alaska Native, 389 (0.3%) were Asian, 37 796 (26.3%) were Black or African American, 933 (0.6%) were Native Hawaiian or other Pacific Islander, 91 091 (63.3%) were White, and 12 927 (9.0%) were of unknown race; 7299 patients (5.1%) were Hispanic or Latino, 128 796 (89.5%) were not Hispanic or Latino, and 7791 (5.4%) were of unknown ethnicity. A total of 52 886 patients (36.8%) received primary radiotherapy, and 91 000 (63.2%) did not. A second primary cancer more than 1 year after prostate cancer diagnosis was present in 4257 patients (3.0%), comprising 1955 patients (3.7%) in the radiotherapy cohort and 2302 patients (2.5%) in the nonradiotherapy cohort. In the multivariable analyses, patients in the radiotherapy cohort had a higher risk of second primary cancer compared with those in the nonradiotherapy cohort at years 1 to 5 after diagnosis (hazard ratio [HR], 1.24; 95% CI, 1.13-1.37; P < .001), with higher adjusted HRs in the subsequent 15 years (years 5-10: 1.50 [95% CI, 1.36-1.65; P < .001]; years 10-15: 1.59 [95% CI, 1.37-1.84; P < .001]; years 15-20: 1.47 [95% CI, 1.08-2.01; P = .02).

CONCLUSIONS AND RELEVANCE

In this cohort study, patients with prostate cancer who received radiotherapy were more likely to develop a second primary cancer than patients who did not receive radiotherapy, with increased risk over time. Although the incidence and risk of developing a second primary cancer were low, it is important to discuss the risk with patients during shared decision-making about prostate cancer treatment options.

Incidence, Mortality, and Treatment Patterns of Synchronous Lower Genital Tract Squamous Cell Carcinoma

OBJECTIVE

The aim of the study was to define the incidence, prognosis, and treatment patterns associated with synchronous lower genital tract squamous cell carcinoma (LGTSCC) among women diagnosed with any LGTSCC.

MATERIALS AND METHODS

Surveillance, Epidemiology, and End Results (SEER) database patients diagnosed with synchronous cervical, vaginal, vulvar, and/or anal SCC from 2000 to 2016 were included. Incidence and mortality were evaluated using Kaplan-Meier curves. Multivariable Cox proportional hazards regression was used to identify treatment patterns, risk factors, and mortality associated with LGTSCC.

RESULTS

Among 15,424 women with LGTSCC, 138 had synchronous LGTSCC (0.89%). Vulvar and vaginal SCC was the most common combination (49.3%), and cervical with anal SCC was the least common (1.4%). Only one patient had 3 or more primary LGTSCC. Synchronous LGTSCC was independently associated with higher mortality compared with single-site LGTSCC (adjusted hazards ratio [aHR] = 1.67; p < .001). Synchronous LGTSCC was significantly associated with older age (63 vs. 58 years, p < .001) and lower stage (adjusted odds ratio [aOR] = 0.38; p < .001) and grade of disease (aOR = 0.32; p < .001). Patients with synchronous LGTSCC were more likely to receive radiation (aOR = 1.74; p = .005) and were more likely to receive adjuvant radiation after primary surgical resection compared with single-site LGTSCC (aOR = 1.88; p = .007). Receipt of any treatment including radiation (aHR = 0.85; p < .001), chemotherapy (aHR = 0.50; p < .001), and surgery (aHR = 0.70; p < .001) was independently associated with decreased mortality hazard.

CONCLUSIONS

Synchronous LGTSCC is rare but is associated with increased mortality and higher rates of adjuvant radiation compared with single-site LGTSCC despite lower stage and grade at diagnosis. More research is needed to define optimal therapy for these patients.

The role for vaginal cuff brachytherapy boost after external beam radiation therapy in endometrial cancer

PURPOSE

To evaluate the role and technique of a vaginal cuff brachytherapy (VB) boost to adjuvant external beam (EB) radiation for endometrial cancer through a systematic review.

METHODS AND MATERIALS

Relevant trials were identified through a systematic search of the literature.

RESULTS

A total of 21 prospective and retrospective studies which had a patient cohort undergoing EB + VB was identified to evaluate for rates of vaginal and pelvic recurrences, overall survival, and toxicity. Additional database studies were utilized to demonstrate differences in local control and overall survival between EB and EB + VB.

CONCLUSIONS

While there is limited prospective evidence to guide the use of a VB boost after EB, the evidence suggests that patients with a higher risk of a vaginal recurrence such as those with cervical stromal involvement in select Stage III patients may derive local control and survival benefits from a VB boost. Additional individual risk factors such as grade, histology, extent of invasion, margin status, age, and the use of lower doses of EB should be considered when deciding when to add a VB boost.

Prostate radiotherapy and the risk of secondary rectal cancer-a meta-analysis

PURPOSE

Radiotherapy is being used increasingly in the treatment of prostate cancer. However, ionising radiation may confer a small risk of a radiation-induced secondary malignancy. We aim to assess the risk of rectal cancer following pelvic radiotherapy for prostate cancer.

METHODS

A search was conducted of the PubMed/MEDLINE, EMBASE and Web of Science databases identifying studies reporting on the risk of rectal cancer following prostatic radiotherapy. Studies must have included an appropriate control group of non-irradiated prostate cancer patients. A meta-analysis was performed to assess the risk of prostatic radiotherapy on subsequent rectal cancer diagnosis.

RESULTS

In total, 4757 articles were screened with eight studies meeting the predetermined criteria. A total of 796,386 patients were included in this meta-analysis which showed an increased odds ratio (OR) for subsequent rectal cancer in prostate cancer patients treated with radiotherapy compared to those treated by non-radiotherapy means (OR 1.45, 1.07-1.97, p = 0.02).

CONCLUSION

These findings confirm that prostate radiotherapy significantly increases the risk of subsequent rectal cancer. This risk has implications for treatment selection, surveillance and patient counselling. However, it is crucial that this information is presented in a rational and comprehensible manner that does not disproportionately frighten or deter patients from what might be their most suitable treatment modality.

Treatment patterns and economic burden among cervical and endometrial cancer patients newly initiating systemic therapy

Aim: To evaluate treatment patterns, healthcare resource use (HCRU) and all-cause healthcare costs among patients with cervical or endometrial cancer newly initiating systemic therapy. Methods: We identified patients with cervical or endometrial cancer newly initiating systemic therapy - a claims-based proxy for advanced disease - between 2014 and 2019, described them by line of therapy (LOT), and summarized the per patient per month (PPPM) HCRU and healthcare costs per LOT. Results: Among 1229 patients with cervical cancer and 2659 patients with endometrial cancer, LOT1 therapies included systemic only (cervical, 50.1%; endometrial, 83.2%) and systemic with radiation therapy (cervical, 49.9%; endometrial, 16.8%). Mean PPPM total costs were: LOT1 (cervical, $15,892; endometrial, $11,363), LOT2 ($20,193; $14,019) and LOT3+ ($16,576; $14,645). Conclusions: Overall, patients received guideline-concordant care and experienced significant economic burden, which increased with LOT.

Incidence and relative risk of metachronous second primary cancers for 16 cancer sites, Osaka, Japan, 2000-2015: Population-based analysis

Background

An increasing number of cancer survivors have developed multiple primaries. This study aims to describe the incidence and risk patterns of metachronous second primary cancers (SPCs) in Osaka, Japan.

Methods

Data were obtained from the Osaka Cancer Registry, a population‐based database of all cancers diagnosed in Osaka. The study subjects were individuals who were first diagnosed with invasive cancers in 16 major cancer sites during 2000–2014, aged 15–79 years, survived at least 3 months, and were followed up for 10 years. We measured incidence rates, cumulative risks, and standardized incidence ratios (SIRs: with the Osaka general population as the referent) of developing SPCs during 3 months to 10 years after the first diagnosis.

Results

During 2000–2015, among 418,791 cancer survivors, 24,368 (5.8%) developed SPCs within 10 years of first diagnosis. Males had higher incidence rates than females except among young‐onset survivors (aged 15–39 years). 10‐year cumulative risks among survivors aged 70–79 years (the most dominant age group) were 24.0% (male) and 11.8% (female). 10‐year SIRs were 1.38 (95% CI, 1.36–1.40; male) and 1.44 (95% CI, 1.41–1.48; female) with higher estimates among younger survivors in both sexes. Strong bidirectional associations were observed between oral/pharyngeal, esophageal, and laryngeal cancers. Survivors of any smoking‐related cancers had elevated SIRs of developing smoking‐related SPCs. Similar results were observed for alcohol‐related cancers.

Conclusions

Cancer survivors are at excess risk of developing SPCs compared to the general population. Continued surveillance is warranted to inform survivorship care through risk‐based long‐term care planning and lifestyle‐changing efforts to prevent new cancers.

Second primary malignancies associated with radiation therapy in cervical cancer patients diagnosed between 1975 and 2011: a population-based competing-risk study

Background

Cervical cancer is a major health threat for women. Radiotherapy plays an important role in the treatment of cervical cancer. However, its overall benefit has been questioned due to the risk of second primary malignancies.

Methods

The Surveillance, Epidemiology, and End Results (SEER) database was used to search for cervical cancer patients diagnosed between January 1975 and November 2011. Factors that could possibly affect the occurrence of second primary malignancies included the year of diagnosis, gender, ethnicity, histologic type, SEER cancer stage, histology, grade, and whether surgery, chemotherapy, or radiotherapy were used. Age-adjusted and propensity scoring matching (PSM)-adjusted competing-risk analysis was applied for analysis.

Results

Of the 23,112 patients identified through SEER, 14,800 (64.0%) received radiotherapy. Second malignancies were diagnosed in 2,545 (11.0%) cases. PSM-adjusted competing analysis revealed that patients receiving radiotherapy had a significantly higher risk of developing a second cancer in the colon, rectum and anus [hazard ratio (HR): 1.43; 95% confidence interval (CI): 1.09-1.87; P=0.01], lung and bronchus (HR: 1.41; 95% CI: 1.13-1.76; P=0.002), corpus uteri (HR: 3.71; 95% CI: 1.71-8.06; P<0.001), ovary (HR: 2.79; 95% CI: 1.38-5.64; P=0.004), and urinary bladder (HR: 2.18; 95% CI: 1.35-3.54; P=0.002). However, radiotherapy significantly lowered the risk of second cancers in the female breast (HR: 0.67; 95% CI: 0.52-0.86; P=0.002). Age-adjusted competing-risk analysis showed generally consistent results.

Conclusions

Radiotherapy increased the risk of second cancers among cervical cancer patients. Those who underwent radiotherapy had a significantly higher risk of developing a second cancer in the colon, rectum and anus, lung and bronchus, corpus uteri, ovary, and urinary bladder.

Cisplatin Reduces the Frequencies of Radiotherapy-Induced Micronuclei in Peripheral Blood Lymphocytes of Patients with Gynaecological Cancer: Possible Implications for the Risk of Second Malignant Neoplasms

Gynaecologic cancers are common among women and treatment includes surgery, radiotherapy or chemotherapy, where the last two methods induce DNA damage in non-targeted cells like peripheral blood lymphocytes (PBL). Damaged normal cells can transform leading to second malignant neoplasms (SMN) but the level of risk and impact of risk modifiers is not well defined. We investigated how radiotherapy alone or in combination with chemotherapy induce DNA damage in PBL of cervix and endometrial cancer patients during therapy. Blood samples were collected from nine endometrial cancer patients (treatment with radiotherapy + chemotherapy-RC) and nine cervical cancer patients (treatment with radiotherapy alone-R) before radiotherapy, 3 weeks after onset of radiotherapy and at the end of radiotherapy. Half of each blood sample was irradiated ex vivo with 2 Gy of gamma radiation in order to check how therapy influenced the sensitivity of PBL to radiation. Analysed endpoints were micronucleus (MN) frequencies, apoptosis frequencies and cell proliferation index. The results were characterised by strong individual variation, especially the MN frequencies and proliferation index. On average, despite higher total dose and larger fields, therapy alone induced the same level of MN in PBL of RC patients as compared to R. This result was accompanied by a higher level of apoptosis and stronger inhibition of cell proliferation in RC patients. The ex vivo dose induced fewer MN, more apoptosis and more strongly inhibited proliferation of PBL of RC as compared to R patients. These results are interpreted as evidence for a sensitizing effect of chemotherapy on radiation cytotoxicity. The possible implications for the risk of second malignant neoplasms are discussed.

Out-of-field organ doses and associated risk of cancer development following radiation therapy with photons

Innovations in cancer treatment have contributed to the improved survival rate of these patients. Radiotherapy is one of the main options for cancer management nowadays. High doses of ionizing radiation are usually delivered to the tumor site with high energy photon beams. However, the therapeutic radiation exposure may lead to second cancer induction. Moreover, the introduction of intensity-modulated radiation therapy over the last decades has increased the radiation dose to out-of-field organs compared to that from conventional irradiation. The increased organ doses might result in elevated probabilities for developing secondary malignancies to critical organs outside the treatment volume. The organ-specific dosimetry is considered necessary for the theoretical second cancer risk assessment and the proper analysis of data derived from epidemiological reports. This study reviews the methods employed for the measurement and calculation of out-of-field organ doses from exposure to photons and/or neutrons. The strengths and weaknesses of these dosimetric approaches are described in detail. This is followed by a review of the epidemiological data associated with out-of-field cancer risks. Previously published theoretical cancer risk estimates for adult and pediatric patients undergoing radiotherapy with conventional and advanced techniques are presented. The methodology for the theoretical prediction of the probability of carcinogenesis to out-of-field sites and the limitations of this approach are discussed. The article also focuses on the factors affecting the magnitude of the probability for developing radiotherapy-induced malignancies. The restriction of out-of-field doses and risks through the use of different types of shielding equipment is presented.

Colorectal Cancer Risk in Women with Gynecologic Cancers-A Population Retrospective Cohort Study

We conducted a retrospective cohort study to evaluate the subsequent colorectal cancer (CRC) risk for women with gynecologic malignancy using insurance claims data of Taiwan. We identified patients who survived cervical cancer (N = 25,370), endometrial cancer (N = 8149) and ovarian cancer (N = 7933) newly diagnosed from 1998 to 2010, and randomly selected comparisons (N = 165,808) without cancer, matched by age and diagnosis date. By the end of 2011, the incidence and hazard ratio (HR) of CRC were estimated. We found that CRC incidence rates were 1.26-, 2.20-, and 1.61-fold higher in women with cervical, endometrial and ovarian cancers, respectively, than in comparisons (1.09/1000 person-years). The CRC incidence increased with age. Higher adjusted HRs of CRC appeared within 3 years for women with endometrial and ovarian cancers, but not until the 4th to 7th years of follow up for cervical cancer survivals. Cancer treatments could reduce CRC risks, but not significantly. However, ovarian cancer patients receiving surgery alone had an incidence of 3.33/1000 person-years for CRC with an adjusted HR of 3.79 (95% CI 1.11-12.9) compared to patients without any treatment. In conclusion, gynecologic cancer patients are at an increased risk of developing CRC, sooner for those with endometrial or ovarian cancer than those with cervical cancer.

Second malignancy probabilities in prostate cancer patients treated with SBRT and other contemporary radiation techniques

BACKGROUND

Prostate radiotherapy has been associated with an increased risk of developing a second malignancy (SM). However, relative SM probabilities following treatment with contemporary radiation techniques such as stereotactic body radiotherapy (SBRT) or moderately hypofractionated intensity modulated radiotherapy (HF-IMRT) remain unknown.

METHODS

A cohort analysis was performed of men from a nationally representative database with localized prostate cancer with at least 60 months of follow-up comparing SM probability amongst men receiving either radical prostatectomy (RP), conventionally fractionated intensity-modulated radiotherapy (CF-IMRT), HF-IMRT, brachytherapy (BT), or SBRT, using multivariable logistic models, which were used to generate predicted probabilities. Additionally, propensity score-adjusted pairwise assessments of modalities were performed.

RESULTS

For 303,432 patients included in the study, median follow-up was 9.08 years (IQR 7.01-11.21). Predicted rates of SM by treatment modality and adjusted odds ratios (AOR) for development of SM (referent: RP) were: 6.0% for RP (AOR n/a), 7.1% for CF-IMRT (AOR 1.20, 95%CI 1.14-1.25, P < 0.001), 7.3% for HF-IMRT (AOR 1.25, 95%CI 1.01-1.55, P = 0.045), 6.6% for BT (AOR 1.11, 95%CI 1.07-1.16, P < 0.001), and 5.7% for SBRT (AOR 0.95, 95%CI 0.81-1.12, P = 0.567). On propensity score-adjusted analysis, SBRT was associated with lower odds of SM compared to CF-IMRT (AOR 0.78, 95%CI 0.66-0.93, P = 0.005); no significant difference was found when SBRT was compared to RP (AOR 0.86, 95%CI 0.73-1.03, P = 0.102).

CONCLUSIONS

Conventionally fractionated intensity-modulated radiotherapy, moderately hypofractionated intensity-modulated radiotherapy, and brachytherapy but not stereotactic body radiotherapy were associated with increased probability of a second malignancy compared to radical prostatectomy. Patients treated with SBRT may be at lower risk of second malignancy due to improved conformality, radiobiological differences or patient selection. The possibility that SBRT in select patients may minimize the probability of SM underscores the need for assessment of second malignancy risk in prospective studies of SBRT.

Radiation Risk of Ovarian Cancer in Atomic Bomb Survivors: 1958-2009

There is limited evidence concerning the association between radiation exposure and ovarian cancer. We evaluated radiation risk of ovarian cancer between 1958 and 2009 among 62,534 female atomic bomb survivors in the Life Span Study cohort, adding 11 years of follow-up from the previously reported study. Poisson regression methods were used to estimate excess relative risk per Gy (ERR/Gy) for total ovarian cancer and according to tumor type. We assessed the modifying effect of follow-up period and other factors on the radiation risk. We ascertained 288 first primary ovarian cancers including 77 type 1 epithelial cancers, 75 type 2 epithelial cancers, 66 epithelial cancers of undetermined type and 70 other cancers. Radiation dose was positively, although not significantly, associated with risk of total ovarian cancer [ERR/Gy = 0.30, 95% confidence interval (CI): -0.22 to 1.11]. There was a suggestion of heterogeneity in radiation effects (P = 0.08) for type 1 (ERR/Gy = -0.32, 95% CI: <-0.32 to 0.88) and type 2 cancers (ERR/Gy = 1.24, 95% CI: -0.08 to 4.16). There were no significant trends in the ERR with time since exposure or age at exposure. Further follow-up will help characterize more accurately the patterns of radiation risk for total ovarian cancer and its types.

Prognostic Model for Predicting Overall and Cancer-Specific Survival Among Patients With Cervical Squamous Cell Carcinoma: A SEER Based Study

BACKGROUND

Cervical squamous cell carcinoma (CSCC) is the most common histological subtype of cervical cancer. The purpose of this study was to assess prognostic factors and establish personalized risk assessment nomograms to predict overall survival (OS) and cancer-specific survival (CSS) in CSCC patients.

METHODS

CSCC patients diagnosed between 1988 and 2015 were identified in the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariate Cox proportional hazard regression models were applied to select meaningful independent predictors and construct predictive nomogram models for OS and CSS. The concordance index (C-index), calibration curve, and receiver operating characteristic (ROC) curve were used to determine the predictive accuracy and discriminability of the nomogram.

RESULTS

A total cohort (n=17962) was randomly divided into a training cohort (n=11974) and a validation cohort (n=5988). Age, race, histologic grade, clinical stage, tumor size, chemotherapy and historic stage were assessed as common independent predictors of OS and CSS. The C-index value of the nomograms for predicting OS and CSS was 0.771 (95% confidence interval 0.762-0.780) and 0.786 (95% confidence interval 0.777-0.795), respectively. Calibration curves of the nomograms indicated satisfactory consistency between nomogram prediction and actual survival for both 3-year and 5-year OS and CSS.

CONCLUSION

We constructed nomograms that could predict 3- and 5-year OS and CSS of CSCC patients. These nomograms showed good performance in prognostic prediction and can be used as an effective tool to evaluate the prognosis of CSCC patients, thus contributing to clinical decision making and individualized treatment planning.

Study of Photoneutron Production for the 18 MV Photon Beam of the Siemens Medical linac by Monte Carlo Simulation

Background:

Considering the importance of photoneutron production in linear accelerators, it is necessary to describe and measure the photoneutrons produced around modern linear accelerators.

Objective:

The aim of the present research is to study photoneutron production for the 18 MV photon beam of a Siemens Primus Plus medical linear accelerator.

Material and Methods:

This study is an experimental study. The main components of the head of Siemens Primus Plus linac were simulated using MCNPX 2.7.0 code. The contribution of different components of the linac in photoneutron production, neutron source strength, neutron source strength and photon and electron spectra were calculated for the flattening filter and flattening filter free cases for the 18 MV photon beam, and was scored for three fields of 5 × 5 cm², 10 × 10 cm² and 20 × 20 cm² in size.

Results:

The results show that the primary collimator has the largest contribution to production of neutrons. Moreover, the photon fluence for the flattening filter free case is 8.62, 6.51 and 4.62 times higher than the flattening filter case for the three fields, respectively. The electron fluences for the flattening filter free case are 4.62, 2.93 and 2.79 times higher than with flattening filter case for the three fields under study, respectively. In addition to these cases, by increasing the field size, the contribution of neutron production related to the jaws is reduced, so that when the field size increases from 5 × 5 cm² to 20 × 20 cm², a 17.93% decrease in photoneutron production was observed.

Conclusion:

In all of the accelerators, the neutron strength also increases with increasing energy. The calculated neutron strength was equal to 0.83×10¹² neutron Gy ⁻¹ at the isocenter.

Ionising radiation as a risk factor for lymphoma: a review

The ability of ionising radiation to induce lymphoma is unclear. Here, we present a narrative review of epidemiological evidence of the risk of lymphoma, including chronic lymphocytic leukaemia (CLL) and multiple myeloma (MM), among various exposed populations including atomic bombing survivors, industrial and medical radiation workers, and individuals exposed for medical purposes. Overall, there is a suggestion of a positive dose-dependent association between radiation exposure and lymphoma. The magnitude of this association is highly imprecise, however, with wide confidence intervals frequently including zero risk. External comparisons tend to show similar incidence and mortality rates to the general population. Currently, there is insufficient information on the impact of age at exposure, high versus low linear energy transfer radiation, external versus internal or acute versus chronic exposures. Associations are stronger for males than females, and stronger for non-Hodgkin lymphoma and MM than for Hodgkin lymphoma, while the risk of radiation-induced CLL may be non-existent. This broad grouping of diverse diseases could potentially obscure stronger associations for certain subtypes, each with a different cell of origin. Additionally, the classification of malignancies as leukaemia or lymphoma may result in similar diseases being analysed separately, while distinct diseases are analysed in the same category. Uncertainty in cell of origin means the appropriate organ for dose response analysis is unclear. Further uncertainties arise from potential confounding or bias due to infectious causes and immunosuppression. The potential interaction between radiation and other risk factors is unknown. Combined, these uncertainties make lymphoma perhaps the most challenging malignancy to study in radiation epidemiology.

Chronic diarrhoea in an oncology patient - Clinical assessment and decision making

Cancer survival is improving rapidly due to advances in treatments that will often involve radiotherapy, chemotherapy and novel biological agents in addition to surgery. This comes at the price of living with chronic symptoms, of which diarrhoea is particularly common. There is good evidence that for many patients these symptoms become part of everyday life, their "normality" is adjusted and symptoms are tolerated even when limiting activities severely. Clinicians often fail to appreciate the impact of these problems, as the focus of follow up tends to be on cancer recurrence. However, the rapid identification of patients in significant trouble can lead to earlier diagnosis of treatable pathologies and improvement of patients' symptoms. The aim of this review is to highlight the mechanisms which cause oncology patients to develop diarrhoea and highlight useful investigational and treatment strategies.

Survivability modelling using Bayesian network for patients with first and secondary primary cancers

BACKGROUND AND OBJECTIVE

Multiple primary cancers significantly threat patient survivability. Predicting the survivability of patients with two cancers is challenging because its stochastic pattern relates with numerous variables.

METHODS

In this study, a Bayesian network (BN) model was proposed to describe the occurrence of two primary cancers and predict the five-year survivability of patients using probabilistic evidence. Eleven types of major primary cancers and contingent occurrences of secondary cancers were investigated. A nationwide two-cancer database involving 7,845 patients in Taiwan was investigated. The BN topology is rigorously examined and imbalanced dataset is processed by the synthetic minority oversampling technique. The proposed BN survivability prognosis model was compared with benchmark approaches.

RESULTS

The proposed model significantly outperformed the back-propagation neural network, logistic regression, support vector machine, and naïve Bayes in terms of sensitivity, which is a critical performance index for the non-survival group.

CONCLUSIONS

Using the proposed BN model, one can estimate the posterior probabilities for every query provided appropriate prior evidences. The potential survivability information of patients, treatment effects, and socio-demographics factor effects predicted by the proposed model can help in cancer treatment assessment and cancer development monitoring.

Clinicopathological characteristics and outcomes of metachronous rectal cancer in patients with a history of cervical cancer with and without remote radiotherapy: Reports of 45 cases

The purpose of this study was to report the clinicopathological characteristics and treatment outcomes of 45 rectal cancer patients who have a history of cervical cancer with or without remote radiotherapy. Twenty-nine patients (64.4%) with a history of cervical cancer treated with pelvic radiotherapy were classified as group A, 16 (35.6%) patients with a history of cervical cancer not treated with radiotherapy were classified as group B. The median duration between radiotherapy for cervical cancer and rectal adenocarcinoma diagnosis was 18 years. At the time of rectal cancer diagnosis, 5 (17.2%) patients presented stage I disease, 15 (51.7%) had stage II, 1 (3.4%) had stage III, and 8 (27.6%) had stage IV. The patients in group A had older age, higher rates of gross ulcerative lesions, low hemoglobin levels, and a lower rate of lymph node metastases. The patients with secondary rectal cancer developed after radiotherapy for cervical cancer usually presented with abnormal abdominal symptoms, such as proctitis, cystitis, or rectal fistula. Higher colostomy rate was found in this group of patients due to severe pelvic fibrosis or proctitis.

RADIATION-INDUCED BYSTANDER EFFECT - MODELING, MANIFESTATION, MECHANISMS, PERSISTENCE, CANCER RISKS (literature review)

The review summarizes and analyzes the data of world scientific literature and the results of the own research con- cerning one of the main non-targeted effects of ionizing radiation - the radiation induced bystander effect (RIBE) - the ability of irradiated target cells to induce secondary biological changes in non-irradiated receptor cells. The his- tory of studies of this phenomenon is presented - it described under various names since 1905, began to study from the end of the twentieth century when named as RIBE and caused particular interest in the scientific community during recent decades. It is shown that the development of biological science and the improvement of research methods allowed to get new in-depth data on the development of RIBE not only at the level of the whole organism, but even at the genome level. The review highlights the key points of numerous RIBE investigations including mod- eling; methodological approaches to studying; classification; features of interaction between irradiated and intact cells; the role of the immune system, oxidative stress, cytogenetic disorders, changes in gene expression in the mechanism of development of RIBE; rescue effect, abscopal effect, persistence, modification, medical effects. It is emphasized that despite the considerable amount of research concerning the bystander response as the universal phenomenon and RIBE as one of its manifestations, there are still enough «white spots» in determining the mech- anisms of the RIBE formation and assessing the possible consequences of its development for human health.

Heterozygous Tsc2 (Tsc2+/–) mouse model to study induced renal cancer in response to ionizing radiation at low doses

Kidneys are one of the main dose-limiting organs in radiotherapeutic procedures of lower abdomen. Likewise, the threat of exposure of radiosensitive organs such as kidneys in warfare or radiation accidents among military personal or due to terrorist activities in general public is of increasing concern. These events warrant the need for appropriate animal models to study the acute and chronic effects of low- and high-dose rate radiation exposures. In this study, for the first time, we validated Tsc2+/– mouse model to study whether radiation accelerates carcinogenesis in kidneys. Tsc2+/– mice at increasing age groups at 8 and 10 months were exposed to repeated doses of gamma radiation (0.4 Gy × 5) and assessed for aggravated kidney tumor formation at 2 months post-irradiation. Animals from irradiated group showed a significant increase in numbers of bilateral, multifocal tumors compared with mock-irradiated animals. Intra-glomerular reactive oxygen species (ROS) levels measured by dihydroethidium florescence showed significant increases in ROS production in irradiated Tsc2+/– mice compared with non-irradiated animals. Similarly, selective hematological parameters and glomerular filtration rate were further reduced significantly in irradiated Tsc2+/– mice. Tsc2 protein, tuberin in irradiated mice, however, remains at the same reduced levels as that of the mock-irradiated heterozygous Tsc2 mice. The results indicate that radiation alters kidney homeostatic function and influences high spontaneous incidence of renal cell carcinoma in this rodent model. Repurposing of Tsc2+/– mice model will, therefore, provide a unique opportunity to study acute and delayed effects of radiation in the development of kidney cancers.

Effect of radiotherapy on the survival of cervical cancer patients: An analysis based on SEER database

Cervical cancer is among the most frequent cancer types in women worldwide. Radiotherapy, including external beam radiation and brachytherapy, is one of the commonly used treatment options for cervical cancer. However, the adverse effects of radiation therapy on cervical cancer survival have been poorly investigated with inconclusive results. Therefore, the aim of this study was to determine the suitable radiotherapy modality according to patients' characteristics. A retrospective survival analysis of 44,602 patients was performed using the Surveillance, Epidemiology, and End Results (SEER) database. Multivariate proportional hazard Cox model was used to evaluate the prognostic impact of different radiotherapy modalities, primary surgery, age, TNM stage, and tumor size. Our results indicated that patients without primary surgery, diagnosed at older age (≥45 years' old), at advanced TNM stages (III/IV) or with larger tumor size (≥3 cm) could benefit from radiotherapy. However, radiotherapy was detrimental in patients with primary surgery, diagnosed at younger age (<45 years' old), at earlier TNM stages (I/II) or with smaller tumor size (<3 cm). In addition, external beam radiation was in most cases less effective compared with combined external beam and brachytherapy. These results highlighted the necessity of realizing personalized radiotherapy treatments for patients with cervical cancer.

Radiation-induced Non-targeted Effect and Carcinogenesis; Implications in Clinical Radiotherapy

Bystander or non-targeted effect is known to be an interesting phenomenon in radiobiology. The genetic consequences of bystander effect on non-irradiated cells have shown that this phenomenon can be considered as one of the most important factors involved in secondary cancer after exposure to ionizing radiation. Every year, millions of people around the world undergo radiotherapy in order to cure different types of cancers. The most crucial aim of radiotherapy is to improve treatment efficiency by reducing early and late effects of exposure to clinical doses of radiation. Secondary cancer induction resulted from exposure to high doses of radiation during treatment can reduce the effectiveness of this modality for cancer treatment. The perception of carcinogenesis risk of bystander effects and factors involved in this phenomenon might help reduce secondary cancer incidence years after radiotherapy. Different modalities such as radiation LET, dose and dose rate, fractionation, types of tissue, gender of patients, etc. may be involved in carcinogenesis risk of bystander effects. Therefore, selecting an appropriate treatment modality may improve cost-effectiveness of radiation therapy as well as the quality of life in survived patients. In this review, we first focus on the carcinogenesis evidence of non-targeted effects in radiotherapy and then review physical and biological factors that may influence the risk of secondary cancer induced by this phenomenon.

Incidences and risk factors of metachronous vulvar, vaginal, and anal cancers after cervical cancer diagnosis

OBJECTIVE

To examine incidences and risk factors for metachronous vulvar, vaginal, and anal malignancies after a cervical cancer diagnosis.

METHODS

This is a retrospective study examining data from the Surveillance, Epidemiology, and End Result Program between 1973 and 2013. Cumulative incidences of vulvar, vaginal, and anal cancers after the diagnosis of cervical cancer were assessed (n = 79,050). Multivariable analysis was performed to determine independent risk factors for these metachronous cancers.

RESULTS

Vaginal cancer (20-year cumulative incidence, 0.57%) was the most common type of metachronous malignancy, followed by vulvar cancer (0.33%), and anal cancer (0.16%, P < 0.001). Median time to diagnosis was 5.4 years for vaginal cancer, 6.5 years for vulvar cancer, and 13.5 years for anal cancer. On multivariable analysis, metachronous vulvar cancer was associated with older age (hazard ratio [HR] per year 1.04, 95% confidence interval [CI] 1.02-1.05, P < 0.001), squamous histology (HR 2.64, 95%CI 1.38-5.05, P = 0.003), and radiotherapy use (HR 2.52, 95%CI 1.66-3.84, P < 0.001); metachronous vaginal cancer was associated with older age (HR per year 1.03, 95%CI 1.02-1.04, P < 0.001) and Black race (HR 1.73, 95%CI 1.20-2.48, P = 0.003); and metachronous anal cancer was associated with older age (HR 1.03, 95%CI 1.01-1.05, P = 0.017). Overall survival of metachronous cancer was poor (5-year rates: 46.3% for vulvar, 43.0% for vaginal, and 47.5% for anal cancer, respectively).

CONCLUSION

Although rare, the rate of ano-genital cancers continues to increase over time after a cervical cancer diagnosis. Long-term follow-up and surveillance after cervical cancer treatment is therefore reasonable to detect these metachronous malignancies, particularly in those with risk factors.

A case of peritoneal malignant mesothelioma following radiation therapy for cervical cancer

The present study presents a case of peritoneal malignant mesothelioma (PMM) following radiation therapy for cervical cancer. A 34-year-old Japanese woman, without asbestos exposure, was referred to the Department of Gynecologic Oncology, Saitama Medical University International Medical Center due to a cervical mass, and was diagnosed with cervical squamous cell carcinoma (SCC). The serum levels of tumor markers, including SCC antigen and cancer antigen 125 (CA125) were 229.0 ng/ml and 54.4 U/ml, respectively. The patient underwent concurrent chemoradiotherapy (CCRT), and a complete response was achieved. After 54 months, ascites was found at the rectouterine pouch, but peritoneal cytology suggested reactive mesothelial cell. After 62 months of CCRT, magnetic resonance imaging revealed masses in both the salpinges. The serum levels of SCC and CA125 were 0.9 ng/ml and 506.1 U/ml, respectively. Following this, left salpingectomy and peritoneal biopsy were performed laparoscopically. Histologic examination revealed atypical mesothelial cells with no continuity of background tubal epithelium. Immunohistochemistry showed positive staining for calretinin, thrombomodulin, mesothelin and glucose transporter 1. Based on these findings, the patient was diagnosed with PMM epithelioid type and underwent systemic chemotherapy; stable disease status has been obtained for 3 months. This case demonstrates the possibility of PMM occurrence within 10 years after radiotherapy, and indicates the importance of histological and immunohistochemical examination, particularly in cases of an atypical tumorigenesis pattern from the primary cancer.

Comparative assessment of late toxicity in patients of carcinoma cervix treated by radiotherapy versus chemo-radiotherapy - Minimum 5 years follow up

BACKGROUND

A randomised trial was carried out comparing chemo-radiation (CTRT) vs. radiotherapy (RT) in patients of carcinoma cervix and showed similar rates of pelvic disease control, disease free survival and overall survival. Late toxicity is presented.

METHODS

Between December 2000 and July 2006, 180 patients of carcinoma cervix were randomly assigned to RT + weekly cisplatin (n = 94) or RT alone (n = 86). Late toxicity was prospectively scored using RTOG criteria in 156 evaluable patients, 79 and 77 respectively and is presented as crude incidence for rectum, bladder, small intestine, vagina, skin and bone and also as actuarial incidence for rectum and bladder.

RESULTS

The median follow up of surviving patients was 10.4 years (minimum - 6.5 years). Crude incidence, CTRT vs. RT, of late toxicities were: rectal (7.5% vs. 5%, p = 0.22), bladder (15% vs. 10.4%, p = 0.76), small bowel (3% vs. 1.2%, p = 0.51), vagina (25% vs. 35%, p = 0.35) while the actuarial risk of grades 3-5 rectal and bladder toxicities by 5 years were 13% vs. 10% (p = 0.698) and 16% vs. 14.8% (p = 0.783) respectively. Bladder toxicity appeared later then rectal toxicity (median 49.4 vs. 21.4 months). Severe bone toxicity (fractures) were higher in the CTRT arm, 5% vs. 0%, p = 0.018. On multivariate analysis vaginal involvement (p = 0.016) and bulky tumor (p = 0.020) were associated with severe vaginal morbidity while rectal point dose > 80% (p = 0.040) was associated with a higher incidence of rectal toxicity.

CONCLUSION

Bone toxicity was significantly increased by addition of CT to RT and patients continued to experience toxicity at longer periods of follow up albeit disease free.

Risk of metachronous ovarian cancer after ovarian conservation in young women with stage I cervical cancer

BACKGROUND

While there is an increasing trend of ovarian conservation at the time of surgical treatment for young women with stage I cervical cancer, the risk for subsequent ovarian cancer after ovarian conservation has not been well studied.

OBJECTIVE

We sought to examine the incidence of and risk factors for metachronous ovarian cancer among young women with stage I cervical cancer who had ovarian conservation at the time of hysterectomy.

STUDY DESIGN

The Surveillance, Epidemiology, and End Results Program was used to identify women aged <50 years who underwent hysterectomy with ovarian conservation for stage I cervical cancer from 1983 through 2013 (n = 4365). Time-dependent analysis was performed for ovarian cancer risk after cervical cancer diagnosis.

RESULTS

Mean age at cervical cancer diagnosis was 37 years, and the majority of patients had stage IA disease (68.2%) and squamous histology (72.9%). Median follow-up time was 10.8 years, and there were 13 women who developed metachronous ovarian cancer. The 10- and 20-year cumulative incidences of metachronous ovarian cancer were 0.2% (95% confidence interval, 0.1-0.4) and 0.5% (95% confidence interval, 0.2-0.8), respectively. Mean age at the time of diagnosis of metachronous ovarian cancer was 47.5 years, and stage III-IV disease was seen in 55.6%. Age (≥45 vs <45 years, hazard ratio, 4.22; 95% confidence interval, 1.16-15.4; P = .018), ethnicity (non-white vs white, hazard ratio, 4.29; 95% confidence interval, 1.31-14.0; P = .009), cervical cancer histology (adenocarcinoma or adenosquamous vs squamous, hazard ratio, 3.50; 95% confidence interval, 1.17-10.5; P = .028), and adjuvant radiotherapy use (yes vs no, hazard ratio, 3.69; 95% confidence interval, 1.01-13.4; P = .034) were significantly associated with metachronous ovarian cancer risk. The presence of multiple risk factors was associated with a significantly increased risk of metachronous ovarian cancer compared to the no risk factor group: 1 risk factor (hazard ratio range, 2.96-8.43), 2 risk factors (hazard ratio range, 16.6-31.0), and 3-4 risk factors (hazard ratio range, 62.3-109), respectively.

CONCLUSION

Metachronous ovarian cancer risk after ovarian conservation for women with stage I cervical cancer is <1%. Older age, non-white ethnicity, adenocarcinoma or adenosquamous histology, and adjuvant radiotherapy may be associated with an increased metachronous ovarian cancer risk.

Identifying a candidate population for ovarian conservation in young women with clinical stage IB-IIB cervical cancer

This study seeks to identify risk factors associated with ovarian metastasis and to characterize a population with minimum risk of ovarian metastasis in young women with stage IB-IIB cervical cancer. This was a nation-wide multicenter retrospective study in Japan examining consecutive cases of surgically-treated women with clinical stage IB-IIB cervical cancer who had oophorectomy at radical hysterectomy (n = 5,697). Multivariable analysis was performed to identify independent risk factors for ovarian metastasis. Ovarian metastasis was seen in 70 (1.2%, 95% confidence interval 0.9-1.5) cases. In the entire cohort, adenocarcinoma, lympho-vascular space invasion, uterine corpus tumor invasion, and pelvic/para-aortic nodal metastases remained independent risk factors for ovarian metastasis (all, adjusted-p < 0.05). In a sensitivity analysis of 3,165 women aged <50 years (ovarian metastasis, 1.0%), adenocarcinoma, parametrial tumor involvement, uterine corpus tumor involvement, and pelvic/para-aortic nodal metastases remained independent risk factors for ovarian metastasis (all, adjusted-P < 0.05). In the absence of these five risk factors (representing 46.1% of women aged <50 years), the incidence of ovarian metastasis was 0.14%. With the presence of adenocarcinoma alone (representing 18.9% of women aged <50 years), the incidence of ovarian metastasis was 0.17% and was not associated with increased risk of ovarian metastasis compared to the subgroup without any risk factors (p = 0.87). In conclusion, nearly two thirds of women aged <50 years with clinical stage IB-IIB cervical cancer had no risk factor for ovarian metastasis or had adenocarcinoma alone: these subgroups had ovarian metastasis rates of around 0.1% and may be a candidate population for ovarian conservation at surgical treatment.

Microvesicles Contribute to the Bystander Effect of DNA Damage

Genotoxic treatments elicit DNA damage response (DDR) not only in cells that are directly exposed but also in cells that are not in the field of treatment (bystander cells), a phenomenon that is commonly referred to as the bystander effect (BE). However, mechanisms underlying the BE remain elusive. We report here that etoposide and ultraviolet (UV) exposure stimulate the production of microvesicles (MVs) in DU145 prostate cancer cells. MVs isolated from UV-treated DU145 and A431 epidermoid carcinoma cells as well as etoposide-treated DU145 cells induced phosphorylation of ataxia-telangiectasia mutated (ATM) at serine 1981 (indicative of ATM activation) and phosphorylation of histone H2AX at serine 139 (γH2AX) in naïve DU145 cells. Importantly, neutralization of MVs derived from UV-treated cells with annexin V significantly reduced the MV-associated BE activities. Etoposide and UV are known to induce DDR primarily through the ATM and ATM- and Rad3-related (ATR) pathways, respectively. In this regard, MV is likely a common source for the DNA damage-induced bystander effect. However, pre-treatment of DU145 naïve cells with an ATM (KU55933) inhibitor does not affect the BE elicited by MVs isolated from etoposide-treated cells, indicating that the BE is induced upstream of ATM actions. Taken together, we provide evidence supporting that MVs are a source of the DNA damage-induced bystander effect.

Epidemiology of Renal Cell Carcinoma

The increasing incidence of RCC in most populations may in part be due to increasing numbers of incidentally detected cancers with new imaging methods. Further, the increase is not only limited to small local tumours but also includes more advanced tumours, which may to some part explain the still high mortality rates. The variation in incidence between populations may have several other explanations. Traditionally the starting point has included thoughts of environmental exposures, which so far have only in part explained the causes of RCC, by means of cigarette smoking and obesity, which may account for approximately 40% of cases in high-risk countries (Table 2). Further, the genetic variations may be of importance as a cause of the difference between populations. Continued research in RCC is needed with the knowledge that nearly 50% of patients die within 5 years after diagnosis. The further search for environmental exposures should take in account the knowledge that RCC consists of different types with specific genetic molecular characteristics. These genetic alterations have in some cases been suggested to be associated with specific exposures. Furthermore, there might exist a modulating effect of genetic polymorphisms among metabolic activation and detoxification enzymes. Hence, a further understanding of the genetic and molecular processes involved in RCC will hopefully give us a better knowledge how to analyse and interpret exposure associations that have importance for both initiation and progression of RCC.

Pelvic inflammatory disease increases the risk of a second primary malignancy in patients with cervical cancer treated by surgery alone

As the number of long-term cervical cancer survivors continues to increase because of improvements in treatment, concerns about second primary malignancy have grown. The high-risk area of second primary cancers in cervical cancer survivors is the pelvis. Pelvic inflammatory disease (PID) could be a useful marker for gynecological cancers. Thus, we designed a large-scale, nationwide, controlled cohort study to investigate whether PID or other risk factors increased the risk of second primary cancers in patients with cervical cancer treated by surgery alone.Between 2000 and 2010, a total of 24,444 cervical cancer patients were identified using the Registry Data for Catastrophic Illness and the National Health Insurance Research Database (NHIRD) of Taiwan. Patients who received definite surgery were selected. To exclude the effect on second primary malignancy by treatment modalities, all cervical patients who ever having received adjuvant or definite radiotherapy or chemotherapy for primary cervical cancer were excluded. Finally, 3860 cervical cancer patients treated by surgery alone without adjuvant treatments were analyzed.Cox proportional hazards model was used for multivariate analysis and the Kaplan-Meier method was used to assess the cumulative risks. Regarding the incidence of second primary cancers, the standardized incidence ratio (SIR) was used.The median follow-up time was 56.6 months. The 6-year cumulative risk of second primary cancers is 0.16% and 0.12% for PID and without PID, respectively. After adjustment for confounders, age of less than 50 years, the presence of diabetes mellitus, and PID were significantly positivity associated with the risk of second primary cancers. The hazard ratios (HRs) of age less than 50 years, diabetes mellitus, and PID were 1.38 (95% CI = 1.11-2.04), 1.40 (95% CI = 1.06-1.85), and 1.35 (95% CI = 1.00-1.81), respectively. A higher incidence of second primary cancers was observed in the genitals, bladder, and colon.In conclusion, the incidence of second primary cancers was higher in the genitals, bladder, and colon in patients with cervical cancer treated with surgery alone. The patients with PID had a higher risk of second primary cancers.

Risk of second primary cancer after a first potentially-human papillomavirus-related cancer: A population-based study

Human papillomaviruses (HPV) are involved in the development of anogenital and head and neck cancers. The purpose of this study was to assess the risk of developing a second primary cancer (SPC) after a first potentially-HPV-related cancer, and to analyze the sites where SPCs most frequently occurred in these patients. All patients with a first cancer diagnosed between 1989 and 2004, as recorded by 10 French cancer registries, were followed up until December 31, 2007. Only invasive potentially-HPV-related cancers (namely, cervical, vagina, vulva, anal canal, penile, oropharynx, tongue and tonsil) were included. Standardized Incidence Ratios (SIRs) were calculated to assess the risk of SPC. A multivariate Poisson regression model was used to model SIRs separately by gender, adjusted for the characteristics of the first cancer. 10,127 patients presented a first potentially-HPV-related cancer. The overall SIR was 2.48 (95% CI, 2.34-2.63). The SIR was 3.59 (95% CI, 3.33-3.86) and 1.61 (95% CI, 1.46-1.78) in men and women respectively. The relative risk of potentially-HPV-related SPC was high among these patients (SIR=13.74; 95% CI, 8.80-20.45 and 6.78; 95% CI, 4.61-9.63 for men and women, respectively). Women diagnosed in the most recent period (2000-2004) showed a 40% increase of their relative risk of SPC as compared with women diagnosed between 1989 and 1994 (ratio of SIRs=1.40; 95% CI, 1.06-1.85). HPV cancer survivors face an increased risk of SPC, especially second cancer. Clinicians may consider this increased risk of developing HPV-related SPC during follow-up to improve subsequent cancer prevention in these patients.

Radiation-Induced Oxidative Stress at Out-of-Field Lung Tissues after Pelvis Irradiation in Rats

OBJECTIVE

The out-of-field/non-target effect is one of the most important phenomena of ionizing radiation that leads to molecular and cellular damage to distant non-irradiated tissues. The most important concern about this phenomenon is carcinogenesis many years after radiation treatment. In vivo mechanisms and consequences of this phenomenon are not known completely. Therefore, this study aimed to evaluate the oxidative damages to out-of-field lung tissues 24 and 72 hours after pelvic irradiation in rats.

MATERIALS AND METHODS

In this experimentalinterventional study, Sprague-Dawleymale rats (n=49) were divided into seven groups (n=7/each group), including two groups of pelvis- exposed rats (out-of-field groups), two groups of whole bodyexposed rats (scatter groups), two groups of lung-exposed rats (direct irradiation groups), and one control sham group. Out- of-field groups were irradiated at a 2×2 cm area in the pelvis region with 3 Gy using 1.25 MeV cobalt-60 gamma-ray source, and subsequently, malondialdehyde (MDA) and glutathione (GSH) levels as well as superoxide dismutase (SOD) activity in out-of-field lung tissues were measured. Results were compared to direct irradiation, control and scatter groups at 24 and 72 hours after exposure. Data were analyzed using Mann-Whitney U test.

RESULTS

SOD activity decreased in out-of-field lung tissue 24 and 72 hours after irradiation as compared with the controls and scatter groups. GSH level decreased 24 hours after exposure and increased 72 hours after exposure in the out-of-field groups as compared with the scatter groups. MDA level in out-of-field groups only increased 24 hours after irradiation.

CONCLUSION

Pelvis irradiation induced oxidative damage in distant lung tissue that led to a dramatic decrease in SOD activity. This oxidative stress was remarkable, but it was less durable as compared to direct irradiation.

The risk of second malignancies after 125I prostate brachytherapy as monotherapy in a single Australian institution

PURPOSE

To report the incidence of second primary cancer (SPC) after ¹²⁵I brachytherapy (BT) for early prostate cancer in an Australian institution.

METHODS AND MATERIALS

All the patients in our cohort had a cystoscopy before the implant. Data were prospectively collected on all subsequent SPC diagnoses. Standardized incidence ratios (SIRs) were calculated to compare data with the Australian population. Kaplan-Meier analysis was used to determine the actuarial second malignancy and pelvic malignancy rates and the death from SPC and from any cause.

RESULTS

A total of 889 patients were followed up for a median of 4.16 (0-13) years with 370 (42%) patients having ≥5 years of followup. Sixty patients subsequently developed an SPC of which 11 were pelvic malignancies. The 5- and 10-year cumulative incidences were 1.3% (95% confidence interval [CI]: 0.6-3) and 3.3% (95% CI: 1-7) for any pelvic malignancy and 1% (95% CI: 0.4-2) and 2.6% (1-6) for bladder cancer, respectively. The SIR was significantly higher than expected for all bladder cancers at 2.9 (95% CI: 1-6) and close to significance (SIR, 3.0; 95% CI: 0.97-7) for bladder cancers within the first 5 years of followup in the subgroup analysis. On multivariate analysis, older age was associated with increased SPC risk and older age and positive smoking status were associated with increased overall mortality, mortality due to SPC, and mortality from second malignancy (p < 0.05).

CONCLUSIONS

There may be a small increased risk of bladder SPC after prostate BT. A tendency toward a higher risk of bladder SPC after BT was found within the first 5 years of followup probably reflecting screening bias.

Optimal cytoreduction, depth of myometrial invasion, and age are independent prognostic factors for survival in women with uterine papillary serous and clear cell carcinomas

OBJECTIVE

The purpose of this study was to investigate the clinicopathological characteristics, treatment methods, and prognostic factors in women with uterine papillary serous carcinoma (UPSC) and uterine clear-cell carcinoma (UCCC).

STUDY DESIGN

All patients who had undergone surgery for UPCS and UCCC between January 1995 and December 2012 were retrospectively reviewed. Patients with missing data, who did not undergo surgical staging and patients with mixed tumor histology were excluded. Multivariate regression models were used to identify the risk factors for overall survival (OS) and progression-free survival (PFS).

RESULTS

A total of 49 UPSC and 22 UCCC women were included. The majority of the patients were at stage I [IA, 22 (31%) and IB, 18 (25.4%)]. Stages II, III, and IV were identified in 9 (12.7%), 13 (18.3%), and 9 (12.7%) of cases, respectively. Optimal cytoreduction was achieved in 71.8% of cases. Recurrences occurred in 16 patients (22.5%). The 5-year OS rates were 67% for UPSC; 76% for UCCC; 68% for both histology, respectively. Multivariate analysis pointed out that age>67 years (odds ratio (OR): 3.85, p = 0.009 and OR: 3.35, p = 0.014), >50% myometrial invasion (MI) (OR: 2.87, p = 0.037 and OR: 2.46, p = 0.046) and optimal cytoreduction (OR: 3.26, p = 0.006 and OR: 2.77, p = 0.015) were the independent prognostic factors for both PFS and OS.

CONCLUSIONS

Our study demonstrated that optimal cytoreduction, >50% MI, and age >67 years are the most significant factors affecting survival in women with UPSC and UCCC.

Postirradiation Leiomyosarcoma of Rectum Presenting as a Polyp: Case Report and Review of the Literature

Radiation-induced leiomyosarcomas of the gastrointestinal tract are rare. Very few cases have been documented to date. The histological similarity to gastrointestinal stromal tumor has raised doubts if many of the cases originally reported to be leiomyosarcoma before the widespread use of CD117 were indeed gastrointestinal stromal tumors. We present a case of post-irradiation leiomyosarcoma presenting as a rectal polyp and review the literature.

The Prognostic Value of Previous Irradiation on Survival of Bladder Cancer Patients

Background: Radiation exposure is an established risk factor for bladder cancer, however consensus is lacking on the survival characteristics of bladder cancer patients with a history of radiation therapy (RT). Confounding patient comorbidities and baseline characteristics hinders prior attempts at developing such a consensus.

Objective: To compare the survival characteristics of patients with suspected radiation-induced second primary cancer (RISPC) of the bladder to those with de novo bladder cancer, taking into account the patient comorbidities and baseline characteristics predictive of survival.

Methods: Retrospective analysis of patients with muscle-invasive (≥T2a) or BCG-refractory stage Tis-T1 urothelial bladder cancer. Patients were excluded if prior RT exposure was used as treatment for bladder cancer or if cause of death was due to post-operative complications. A digit matching propensity score algorithm was used to match patients with prior radiation treatment to those without prior treatment. Cox regression analysis for time until death was performed following creation of the propensity score matched sample.

Results: 29 patients with history of RT were matched with two controls each, resulting in a dataset of 87 observations in the event model. Results from the Cox model indicate a significantly increased hazard ratio for death at 2.22 (p = 0.047, 95% CI: 1.015–4.860) given a history of prior radiation therapy.

Conclusions: In a small cohort, bladder cancer patients who underwent cystectomy had a significantly higher risk of death in the face of prior pelvic RT. This effect was found to be independent of surgical complications, numerous established patient characteristics and comorbidities traditionally predictive of survival.