Risk Of Second Malignant Neoplasms Research Articles

Genetic risk of second malignant neoplasm after childhood cancer treatment: A systematic review.

Second malignant neoplasm (SMN) is one of the most severe long-term risks for childhood cancer survivors (CCS), significantly impacting long-term patient survival. While radiotherapy and chemotherapy are known risk factors, the observed inter-individual variability suggests a genetic component contributing to the risk of SMN. This article aims to conduct a systematic review of genetic factors implicated in the SMN risk among CCS. Searches were performed in PubMed, Scopus, and Web of Sciences. Eighteen studies were included (eleven candidate gene studies, three genome-wide association studies, and four whole exome/genome sequencing studies). The included studies were based on different types of first cancers, investigated any or specific types of SMN, and focused mainly on genes involved in drug metabolism and DNA repair pathways. These differences in study design and methods used to characterize genetic variants limit the scope of the results and highlight the need for further extensive and standardized investigations. However, this review provides a valuable compilation of SMN risk-associated variants and genes, facilitating efficient replication and advancing our understanding of the genetic basis for this major risk for CCS.

Tandem High-Dose Chemotherapy Increases the Risk of Secondary Malignant Neoplasm in Pediatric Solid Tumors.

This study aimed to investigate the incidence and risk factors for secondary malignant neoplasms (SMN) in pediatric solid tumors, focusing on the effects of tandem high-dose chemotherapy (HDCT). Patients (aged < 19 years) diagnosed with or treated for pediatric solid tumors between 1994 and 2014 were retrospectively analyzed. The cumulative incidence of SMN was estimated using competing risk methods by considering death as a competing risk. A total of 1,435 patients (413 with brain tumors and 1,022 with extracranial solid tumors) were enrolled. Seventy-one patients developed 74 SMNs, with a 10-year and 20-year cumulative incidence of 2.680±0.002% and 10.193±0.024%, respectively. The types of SMN included carcinoma in 28 (37.8%), sarcoma in 24 (32.4%), and hematologic malignancy in 15 (20.3%) cases. Osteosarcoma and thyroid carcinoma were the most frequently diagnosed tumors. Multivariate analysis showed that radiotherapy (RT) > 2, 340 cGy, and tandem HDCT were significant risk factors for SMN development. The SMN types varied according to the primary tumor type; carcinoma was the most frequent SMN in brain tumors and neuroblastoma, whereas hematologic malignancy and sarcomas developed more frequently in patients with sarcoma and retinoblastoma, respectively. The cumulative incidence of SMN in pediatric patients with solid tumors was considerably high, especially in patients who underwent tandem HDCT or in those who received RT > 2,340 cGy. Therefore, the treatment intensity should be optimized based on individual risk assessment and the long-term follow-up of pediatric cancer survivors.

Second malignant neoplasms within 5 years from first primary diagnosis in pediatric oncology patients in Canada: a population-based retrospective cohort study.

From the advancement of treatment of pediatric cancer diagnosis, the five-year survival rate has increased significantly. However, the adverse consequence of improved survival rate is the second malignant neoplasm. Although previous studies provided information on the incidence and risk of SMN in long term survivors of childhood cancer, there is still scarce information known for short term (< 5 years) prognosis. This study aims to assess the incidence, characteristics, management, and outcome of children who develop SMN malignancies within 5 years of diagnosis of their initial cancer. This is a retrospective cohort study of early Second Malignant Neoplasms (SMN) in pediatric oncology patients. The Cancer in Young People - Canada (CYP-C) national pediatric cancer registry was used and reviewed pediatric patients diagnosed with their first cancer from 2000-2015. A total of 20,272 pediatric patients with a diagnosis of a first malignancy were analyzed. Of them, 0.7% were diagnosed with a SMN within the first 5 years following their first cancer diagnosis. Development of a SMN impacted survival, shown by an inferior survival rate in the SMN cohort (79.1%) after three years compared to that of the non-SMN cohort (89.7%). Several possible risk factors have been identified in the study including the use of epipodophyllotoxins, exposure to radiation, and hematopoietic stem cell 169 transplant. This is the first national study assessing the incidence, 170 characteristics, risk factors and outcome of early SMN in Canadian children 171 from age 0-15 from 2000-2015.

Risk of Second Tumors in Retinoblastoma Survivors after Ionizing Radiation: A Review.

Retinoblastoma (RB) is the most common ocular neoplasm in children, whose development depends on two mutational events that occur in both alleles of the retinoblastoma susceptibility gene (RB1). Regarding the nature of these mutational events, RB can be classified as hereditary if the first event is a germline mutation and the second one is a somatic mutation in retina cells or nonhereditary if both mutational events occur in somatic cells. Although the rate of survival of RB is significantly elevated, the incidence of second malignant neoplasms (SMNs) is a concern, since SMNs are the main cause of death in these patients. Effectively, RB patients present a higher risk of SMN incidence compared to other oncology patients. Furthermore, evidence confirms that hereditary RB survivors are at a higher risk for SMNs than nonhereditary RB survivors. Over the decades, some studies have been performed to better understand this subject, evaluating the risk of the development of SMNs in RB patients. Furthermore, this risk seems to increase with the use of ionizing radiation in some therapeutic approaches commonly used in the treatment of RB. This review aims to clarify the effect of ionizing radiation in RB patients and to understand the association between the risk of SMN incidence in patients that underwent radiation therapy, especially in hereditary RB individuals.

Features of the Course of Radioinduced Breast Cancer. Clinical Observation

Introduction. Hodgkin’s lymphoma is most commonly reported in the young age of 20 to 40 years. Radiation therapy remained the first-choice option before the advent of modern chemotherapy agents. Thereafter, the risk of radioinduced breast cancer after radiotherapy with total radiation dose of 38 Gy or more increased 4.5-fold.Materials and methods. The presented clinical case demonstrates aggressive breast cancer that developed 43 years after radiation therapy for Hodgkin's lymphoma.Results and discussion. In the 1990s, chemotherapy regimens for Hodgkin’s lymphoma were not effective enough to control the disease, therefore, radiotherapy was an indispensable measure. Secondary radioinduced tumors take the second place (26 %) in the structure of mortality from Hodgkin’s lymphoma. The emergence of new, more effective chemotherapy regimens reduced the risk of secondary tumors and, in particular, breast cancer.Conclusion. At present, up to 75 % of patients with Hodgkin’s lymphoma can be cured using modern methods of chemotherapy and radiation therapy. In follow-up care, it is necessary to consider the high risk of secondary malignant neoplasms, especially lung and breast cancer.

Patient age as a predictive factor in biochemical recurrence following brachytherapy: Oncological outcomes at a single center.

Iodine-125 low-dose-rate brachytherapy (LDR-BT) is a treatment modality utilized in both localized and advanced prostate cancer (PCa). We aimed to evaluate the long-term oncological outcomes in patients with PCa who underwent LDR-BT, at a single institution in Japan. We retrospectively reviewed the clinical records of 340 consecutive patients with localized PCa who underwent LDR-BT between August 2004 and December 2014 at our institution. Patients with low-risk PCa who had a pretreatment prostate volume >50mL received neoadjuvant androgen deprivation therapy (ADT) for at least 3months before LDR-BT. Patients with intermediate-risk PCa were treated with a combination of LDR-BT and/or external beam radiation therapy (EBRT) and/or ADT for 9months. Patients with high-risk PCa underwent LDR-BT, EBRT, and ADT for 24months. The endpoints of this study were biochemical recurrence-free survival (BRFS) and overall survival (OS). Additionally, the association between biochemical recurrence (BCR) and clinical/pathological covariates was analyzed. At the end of the follow-up period, nine patients (2.6%) showed BCR, and six patients (1.8%) developed secondary cancers after LDR-BT. The 5-year and 10-year BRFS rates were 99.4% and 95.3%, respectively. Factoring in the patients' ages, the 5-year and 10-year BRFS rates were 99.1% and 99.1%, respectively, in patients aged >63years. The rates were 100% and 89.4% in those aged ≤63years, respectively. In the multivariate analysis, age ≤63years was identified as a significant independent predictor of BCR after LDR-BT. Age ≤63years was a significant predictor of BCR following LDR-BT. Although the risk of secondary malignant neoplasms should be considered when opting for LDR-BT in younger patients with PCa, the prevalence of them in these patients is relatively low. Therefore, clinicians should weigh the risks and benefits of definitive therapy in PCa, particularly in younger patients.

Risk and prognosis of secondary malignant neoplasms after radiation therapy for bladder cancer: A large population-based cohort study.

To investigate the association between radiotherapy and the risk of second malignant neoplasm (SMN) development among patients with bladder cancer (BC). Overall survival (OS) is compared among patients developing SMN and without. We identified patients diagnosed with BC from the Surveillance, Epidemiology, and End Results (SEER) database. The development of an SMN is defined as any SMN occurring more than 5 years after the diagnosis of BC. The Fine-Gray competing risk regression is used to estimate the probability of SMN. The radiotherapy-associated risk (RR) for SMNs is assessed by Poisson regression. The Kaplan-Meier method was used to evaluate the OS of patients with SMNs. Propensity score matching (PSM) is performed. A total of 76575 BC patients are enrolled in our study. The probability of SMNs in the radiotherapy cohort is statistically higher than in the non-radiotherapy cohort. In competing risk regression analysis, radiotherapy is proven to be associated with a higher risk of SMN (Hazard ratio: 1.23; 95% CI: 1.102-1.368). The radiotherapy-associated risks significantly increase in the radiotherapy cohort (RR: 1.28; 95% CI: 1.14-1.43). In site-specific analysis, statistically significant results are observed in lung and bronchus (LAB) cancer and hematological malignancies. The OS rate in patients developing SMN is significantly lower than that among matched patients with primary BC. Radiotherapy for BC is associated with SMN. Radiotherapy increases the risk of secondary low-dose area cancer development, including LAB cancer or hematological malignancies. Notably, this effect is not observed in the high-dose area involving pelvic tumors. Patients developing SMN showed poorer OS.

Dexrazoxane for preventing or reducing cardiotoxicity in adults and children with cancer receiving anthracyclines.

Dexrazoxane for preventing or reducing cardiotoxicity in adults and children with cancer receiving anthracyclines.

Cell Type-Specific Patterns in the Accumulation of DNA Damage Following Multifractional Radiation Exposure.

Predicting the risk of second malignant neoplasms is complicated by uncertainties regarding the shape of the dose-response relationship at high doses. Limited understanding of the competitive relationship between cell killing and the accumulation of DNA lesions at high doses, as well as the effects of other modulatory factors unique to radiation exposure during radiotherapy, such as dose heterogeneity across normal tissue and dose fractionation, contribute to these uncertainties. The aim of this study was to analyze the impact of fractionated irradiations on two cell systems, focusing on the endpoints relevant for cancer induction. To simulate the heterogeneous dose distribution across normal tissue during radiotherapy, exponentially growing VH10 fibroblasts and AHH-1 lymphoblasts were irradiated with 9 and 12 fractions (VH10) and 10 fractions (AHH-1) at 0.25, 0.5, 1, or 2 Gy per fraction. The effects on cell growth, cell survival, radiosensitivity and the accumulation of residual DNA damage lesions were analyzed as functions of dose per fraction and the total absorbed dose. Residual γH2AX foci and other DNA damage markers (micronuclei, nuclear buds, and giant nuclei) were accumulated at high doses in both cell types, but in a cell type-dependent manner. The competitive relationship between cell killing and the accumulation of carcinogenic DNA damage following multifractional radiation exposure is cell type-specific.

The Impact of Radiation Therapy on the Incidence of Second Malignant Neoplasm among Adolescent and Young Adult Cancer Survivors

<h3>Purpose/Objective(s)</h3> The risks of second malignancy, including radiation-associated malignancies, are well described in adult populations as well as among pediatric patients. Adolescents and young adults (AYA) are a vulnerable population in which the risks of late effects may be increased relative to older adult patients but are not fully characterized. We sought to investigate the incidence second malignant neoplasm among AYA patients and hypothesize that receiving radiation therapy is associated with increased risk of secondary cancers in this population. <h3>Materials/Methods</h3> The Surveillance, Epidemiology, and End Results (SEER) Research Plus database was queried for patients age 15-39 who survived at least 5 years after diagnosis of a solid-tumor primary malignancy between 1975-2017. Descriptive statistics were obtained and univariate comparisons were performed using ANOVA and chi-square test. The 15-year cumulative incidence of second malignant neoplasm (SMN) was calculated among AYA patients overall, among those who did vs did not receive radiation therapy, and across other significant variables. A multivariable model was created to assess the effect of receiving radiation therapy on the risk of SMN when adjusting for age, sex, decade of diagnosis, and disease. <h3>Results</h3> A total of 159,829 AYA patients with ≥5-year survival were included, 31.1% of whom received radiation therapy. Median follow up among the entire cohort was 17 years (range, 5-43 years). The cumulative incidence of SMN among all AYA patients at 15 years was 5.6%. The cumulative incidence of SMN at 15 years was significantly increased among AYA patients who received radiation therapy as part of their definitive treatment (6.6% with radiation therapy versus 5.1% without, p<0.001). Cumulative incidence of SMN was also affected by sex, age, decade of initial diagnosis, and AYA primary cancer diagnosis (see Table 1). On multivariable analysis, patients who received radiation therapy remained more likely to develop a second malignancy than those who did not (HR 1.4, p<0.001). <h3>Conclusion</h3> This study uses national data to report the incidence of second malignancy among adolescents and young adults diagnosed with cancer. Receiving radiation therapy was associated with an increase in SMN at 15 years, with an absolute increase of 1.5% and HR of 1.4 compared to those who did not receive radiation. These results provide an important reference for counseling patients regarding risks of treatment and should guide further efforts to improve treatment delivery and outcomes among this vulnerable population.

Risk of Secondary Malignant Neoplasms in Children Following Proton Therapy vs. Photon Therapy for Primary CNS Tumors

<h3>Purpose/Objective(s)</h3> Central nervous system tumors are the second most common primary neoplasms seen in children and radiation therapy is a key component in management of most of these tumors. Secondary malignant neoplasms (SMNs) are rare but dreaded complications, particularly in the pediatric population. Proton beam therapy (PBT) can potentially minimize the risk of SMNs compared to conventional photon radiation therapy (RT). Multiple recent studies with mature data have reported the risk of SMNs after PBT. We performed this systematic review and meta-analysis to characterize and compare the incidence of SMNs after proton and photon-based radiation for pediatric CNS tumors. <h3>Materials/Methods</h3> A systematic search of literature on electronic (PubMed, Cochrane Central, and Embase) databases was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method. We included studies reporting incidence and nature of SMNs in pediatric patients with primary CNS tumors. The crude incidence of SMNs and all secondary neoplasms were separately extracted, the random-effects model was used for pooled analysis and subgroup comparison was performed between studies using photons vs protons. <h3>Results</h3> Twenty-four studies (21 with conventional RT and 4 with PBT) were included for meta-analysis after performing the systematic review. A total of 418 SMNs and 645 any secondary neoplasms were seen in 38163 patients overall. The most common secondary neoplasms seen were gliomas (40.6%) followed by meningiomas (38.7%), sarcomas (4.8%), thyroid cancers (4.2%), and basal cell carcinomas (1.3%). The overall median follow-up was 8.8 years (range: 3.3 to 23.2 years), while the median latency to a secondary cancer was 9.8 years (range: 5 to 23 years). The median latency to a secondary cancer for photons and protons was 11.9 years (range: 5 to 23 years) and 5.9 years (range: 5 to 6.7 years), respectively. The pooled incidence of SMNs was 1.8% (95% CI: 1.1% – 2.6%, I²=94%) with photons and 1.5% (95% CI: 0 - 4.5%, I²=81%) with protons. There was no significant difference among the two subgroups (p = 0.91). Similarly, the pooled incidence of all secondary neoplasms was not different among the two subgroups [photons: 3.6% (95% CI: 2.5% – 4.8%, I²=96%) vs protons: 1.5% (95% CI: 0 – 4.5%, I²=80%); p = 0.21]. <h3>Conclusion</h3> We observed a slightly lower rate of SMN with PBT at 1.5% compared to 1.8% with photon-based RT for pediatric CNS tumors, although the difference was not statistically significant. We observed a shorter latency to secondary cancers with proton therapy compared to photon-based radiation, which may be related to secondary neutron exposure. With increasing use of techniques that decrease the irradiated tissue volume outside the clinical target volume, like pencil beam scanning proton therapy and VMAT, further studies with longer follow-up are warranted to evaluate the risk of secondary cancers in patients treated with these newer modalities.

Risk of Second Malignant Neoplasm in Familial Non-Medullary Thyroid Cancer Patients.

IntroductionSurvival rates in patients with non-medullary thyroid carcinoma (NMTC) are high, increasing the possibility to develop a second malignant neoplasm (SMN). Many studies investigated the relationship between increased risk of SMN in NMTC patients treated with radioiodine, but few data are available about the impact of family history (FH) of thyroid cancer on SMN risk.PurposeTo assess the risk of SMN in a large cohort of sporadic and familial NMTC using the standardized incidence ratio (SIR).Patients and methodsWe studied 918 NMTC patients (73.9% female patients) followed for a median follow-up of 9 years. In 798/918 (86.9%) patients, NMTC was sporadic, while the remaining 120 (13.1%) were familial NMTC (FNMTC).ResultsWe identified 119/918 (13%) patients with SMN in association with NMTC. NMTCs had an increased risk of SMN when compared to the general population (SIR 2.1, 95% CI 1.7–2.5). The rate of SMN for all sites was significantly higher in familial compared to sporadic NMTC (20% versus 11.9%, p = 0.01), primarily driven by families with more than two affected members. The risk of SMN was remarkably higher for breast cancer, especially in familial cases (SIR 22.03, 95% CI 14.4–41.2) compared to sporadic cases (SIR:17, 95% CI 11.9–24.6).ConclusionsNMTC patients have a higher risk of SMN compared to the general population and this risk is much higher in patients with FNMTC. This observation raises the hypothesis that genetic risk factors for a first cancer may predispose to SMN, especially among individuals with familial clustering of the same or other tumors.

Second cancer risk in childhood cancer survivors treated with intensity-modulated radiation therapy: An updated analysis of more than 10years of follow-up.

It is unclear how intensity-modulated radiation therapy (IMRT) impacts long-term risk of second malignant neoplasms (SMNs) in childhood cancer patients. Patients aged ≤21years treated with IMRT between 1998 and 2009 and who survived ≥5years after IMRT were included. SMN site in relation to isodose level (IDL) of IMRT was evaluated. Standardized incidence ratios (SIR) and excess absolute risks (EAR) were calculated. Cumulative incidences were estimated with death as a competing risk. Three-hundred twenty-five patients were included with median follow-up of 11.2years from IMRT (interquartile range: 9.4-14.0) among patients alive at the end of follow-up. Two hundred (62%) patients had ≥10years of follow-up and 284 (87%) patients were alive at the time of analysis. Fifteen patients developed SMNs (11 solid, four hematologic). Median time from IMRT to solid SMN was 11.0years (range: 6.8-19.2) with 10- and 15-year cumulative incidences 1.8% (95% CI: 0.7-3.9) and 3.5% (95% CI: 1.4-7.5), respectively; SIR was 13.7 (95% CI: 6.9-24.6) and EAR was 2.8 per 1000person-years (95% CI: 1.0-4.6). Eight solid SMNs developed within the IMRT field (100% IDL [n = 5], 80% IDL [n = 1], 50% IDL [n = 1], 40% IDL [n = 1]), one within the 70%-80% IDL of a conventional field, one was out-of-field, and one could not be determined. With median follow-up of >10years, many solid SMNs after IMRT in childhood cancer survivors develop in the high-dose region. These data serve as a foundation for comparison with other modalities of radiation treatment (e.g., proton therapy).

Late Mortality, Subsequent Malignant Neoplasms and Hospitalisations in Long-Term Survivors of Adolescent and Young Adult Hematological Cancers.

BackgroundIncreased success in the treatment of hematological cancers contributed to the increase of 5-year survival for most adolescent and young adults (AYAs) with these tumours. However, as 5-year survival increased, it became clear that AYA long-term survivors were at increased risk for severe late effects. Moreover, limited information on long-term cancer impact is available for AYAs, since most studies focused on children and adolescents. We aimed to assess various long-term outcomes on AYA survivors of hematological cancers.MethodsWe selected patients diagnosed with a first primary hematological cancer between 1997 and 2006, in the Italian nationwide population-based cohort of AYA cancer survivors (i.e. alive at least 5 years after cancer diagnosis). Long-term outcomes of interest were: second malignant neoplasms (SMNs), hospitalizations and overall mortality. We calculated standardized incidence ratios (SIRs), standardized hospitalization rate ratios (SHRs) and standardized mortality rate ratios (SMRs). To study morbidity patterns over time, we modeled observed incidence rates by fitting flexible parametric models for nonlinear patterns and we used linear regression for linear patterns.ResultsThe study cohort included 5,042 AYA hematological cancer survivors of which 1,237 and 3,805 had a leukaemia and lymphoma diagnosis, respectively. AYA survivors were at substantially increased risk for SMN (SIR=2.1; 95%CI=1.7; 2.6), hospitalisation (SHR=1.5; 95%CI=1.5; 1.6), and mortality (SMR=1.4; 95%CI=1.2; 1.6) with differences between leukaemia and lymphoma survivors. The highest excess risks of hospitalisations were for infectious diseases, respiratory diseases, and diseases of blood and blood-forming organs. The morbidity pattern differs over time by morbidity type.ConclusionsOur results support the need for strict follow-up plans for survivors, and call for further study to better personalised follow-up plans for AYA cancer survivors.

Racial/Ethnic Disparities on the Risk of Second Malignant Neoplasm Among Hodgkin Lymphoma Survivors.

BackgroundHodgkin lymphoma survivors are at risk for second malignant neoplasm (SMN). How race/ethnicity affects the risk remains unclear.MethodsThis retrospective cohort study included 22,415 patients diagnosed with primary Hodgkin lymphoma from January 1992 to December 2015 in 13 Surveillance, Epidemiology, and End Results-based registries and divided patients into four groups: non-Hispanic whites, non-Hispanic blacks, Hispanics, and Asian/others. Taking non-Hispanic whites as a reference, both the proportional subdistribution hazard (PSH) and the cause-specific hazard (CSH) methods were used to calculate the SMN hazard ratio for other racial/ethnic groups with and without considering the competing mortality risk.Results1,778 patients developed SMN with a median follow-up of 11.63 years. In the adjusted PSH model, Hispanic, Asian/others, and non-Hispanic black patients had 26% (PSH, 0.74; 95% CI, 0.63–0.87), 20% (PSH, 0.80; 95% CI, 0.64–1.01), and 12% (PSH, 0.88; 95% CI, 0.75–1.03) decreased overall SMN hazard, respectively. Moreover, the PSH method revealed the racial/ethnic difference in the SMN risk in the skin, the respiratory system, and the endocrine system. These hazards were slightly higher and different with the use of the CSH approach. In addition to the aforementioned overall SMN and subtypes, adjusted CSH analysis also revealed the racial/ethnic disparities in the risk of subsequent female breast cancer, digestive cancer, and non-Hodgkin lymphoma.ConclusionsThe subtype and SMN risk among Hodgkin lymphoma survivors varied by race/ethnicity. The use of CSH and PSH provides a dynamic view of racial/ethnic effects on SMN risk in Hodgkin lymphoma survivors.

Intensity Modulated Proton Therapy Better Spares Non-Adjacent Organs and Reduces the Risk of Secondary Malignant Neoplasms in the Treatment of Sinonasal Cancers.

This study compare dosimetric parameters and secondary malignancy risk (SMN) using intensity modulated proton therapy (IMPT) and volumetric modulated arc therapy (VMAT) plans for the treatment of sinonasal cancer (SC). After IRB-approval, 10 patients previously treated with IMPT for cancers of the ethmoid, sphenoid, maxillary, or frontal sinuses were identified. Dosimetrists blinded to the IMPT plans generated VMAT plans for comparison. Volume coverage and dose to organs at risk (OAR) were recorded and compared. Organ equivalent dose (OED) of tissues outside of the treatment volume was used to define the excess absolute and relative risk of SMNs. In all cases, both VMAT and IMPT provided acceptable target volume coverage and were able to meet OAR constraints. IMPT was superior for brain V10, V30, and mean, brainstem D0.01 ipsilateral cochlea V30, contralateral cochlea mean, contralateral lacrimal gland mean, contralateral parotid mean, spinal cord D0.01 and body outside of the CTV V10, V20, and V30. VMAT was superior for ipsilateral eye mean, ipsilateral lens mean, CTV V100 and maximum hotspot. The relative risk of SMNs with VMAT compared to IMPT is 3.35 (95% CI, 1.92-5.89). For the treatment of SC, IMPT spares OARs that are not immediately adjacent to the treatment volume and reduces the risk of SMNs when compared to VMAT. VMAT spares OARs abutting the target volume better than IMPT and has more homogenous target coverage. Tumors of the ethmoid sinus, benefit more from IMPT, while tumors located elsewhere require application of our findings on a case by case basis.

Avoidance or adaptation of radiotherapy in patients with cancer with Li-Fraumeni and heritable TP53-related cancer syndromes.

The management of patients with cancer and Li-Fraumeni or heritable TP53-related cancer syndromes is complex because of their increased risk of developing second malignant neoplasms after genotoxic stresses such as systemic treatments or radiotherapy (radiosusceptibility). Clinical decision making also integrates the risks of normal tissue toxicity and sequelae (radiosensitivity) and tumour response to radiotherapy (radioresistance and radiocurability). Radiotherapy should be avoided in patients with cancer and Li-Fraumeni or heritable TP53 cancer-related syndromes, but overall prognosis might be poor without radiotherapy: radioresistance in these patients seems similar to or worse than that of the general population. Radiosensitivity in germline TP53 variant carriers seems similar to that in the general population. The risk of second malignant neoplasms according to germline TP53 variant and the patient's overall oncological prognosis should be assessed during specialised multidisciplinary staff meetings. Radiotherapy should be avoided whenever other similarly curative treatment options are available. In other cases, it should be adapted to minimise the risk of second malignant neoplasms in patients who still require radiotherapy despite its genotoxicity, in view of its potential benefit. Adaptations might be achieved through the reduction of irradiated volumes using proton therapy, non-ionising diagnostic procedures, image guidance, and minimal stray radiation. Non-ionising imaging should become more systematic. Radiotherapy approaches that might result in a lower probability of misrepaired DNA damage (eg, particle therapy biology and tumour targeting) are an area of investigation.

Risk of developing second malignant neoplasms in patients with neuroblastoma: a population study of the US SEER database

BackgroundNeuroblastoma is a common extracranial malignant tumor in children. Its main treatment modality is a combination of chemotherapy, radiotherapy, and surgery. Given the advances in chemotherapy regimens and the widespread use of bone marrow transplantation over the decades, there has been improvement in treatment efficacy, which has led to prolonged patient survival. Accordingly, long-term complications have become a growing concern among physicians and patients. This study aimed to analyze the survival rate of patients with neuroblastoma and the risk factors for developing second malignant neoplasms (SMNs).MethodsThe SEER 18 Regs (1973–2015) and SEER 9 Regs (1973–2015) data of the surveillance, epidemiology, and end results (SEER) database of the US National Cancer Institute were adopted for survival and SMN analysis.ResultsThe 5-, 10-, and 20-year overall survival rates of patients with neuroblastoma were 67%, 65%, and 62%, respectively. Among 38 patients with neuroblastoma who presented with SMNs, those with abdomen as the primary site accounted for the majority (63.2%), followed by those with thorax (26.3%) and other sites (10.5%). SMNs occurred more commonly in non-specific neuroblastoma (incidence: 0.87%) than ganglioneuroblastoma (incidence: 0.3%). Compared with the general population, the risk of SMN is significantly higher (SIR = 4.36). The risk of developing SMNs was significantly higher in the digestive system (SIR = 7.29), bones and joints (SIR = 12.91), urinary system (SIR = 23.48), brain and other nervous systems (SIR = 5.70), and endocrine system (SIR = 5.84). Multivariate analysis revealed that the year of diagnosis (OR = 2.138, 95% CI = 1.634–2.797, p < 0.001) was the only independent risk factor for developing SMNs.ConclusionThis study identifies the risk factor for developing SMNs in patients with neuroblastoma, which could facilitate individualized screening for high-risk patients, to allow early diagnosis and treatment of SMNs.

Second Malignant Neoplasms (SMN) in Myeloma Patients Post Stem Cell Transplant (SCT)

Introduction: Recent developments in management of patients with myeloma have resulted in longer survival. Availability of newer class of agents for treatment has prolonged survival, improved quality of life and achieved better disease control. Use of SCT, either autologous (AutoSCT) and to a lesser extent allogeneic (AlloSCT) still forms an important aspect of myeloma treatment pathway. Improved survivorship mandates evaluation of long term consequences and risk of SMN is one of the most important long-term consequences affecting overall outcome.Aim: Estimate the risk of SMN post SCT in patients with Myeloma.Methods and Materials: Analysis includes 779 patients who received SCT for myeloma from January 2002 to December 2019. Data was collected using case records, electronic patient records, transplant database and information from referring hospitals. Follow-up was updated to June 2020.Results: Analysis includes 779 patients with myeloma (M: 488, F:291; median age:59yr, range: 26-75) receiving AutoSCT (n=716) or AlloSCT (n=63). Conditioning for AutoSCT was high dose melphalan in majority (n=714, 99.7%). AlloSCT conditioning was RIC (n=40/63, 63.5%) or MAC (n=23/63, 36.5%). TBI was part of conditioning in 51/779 (6.5%). There was no difference in demographics between two groups.Results: Median follow-up was 46 mo (range: 0.2-220). Second malignancy was identified in 48 of 779 cases (6.0%). SMN developed in 6/63 (10%) AlloSCT and 42/716 (6%) AutoSCT patents (p=0.25). SMN types were haematological (n=21), lymphoma (n=6) and solid tumours (n=21). MDS was the only haematological SMN in this series. Secondary MDS developed in 20/21 of AutoSCT as compared to 1/63 in AlloSCT (p=0.01). Non-haematological SMN were breast (n=3), upper GI (n=3), lower GI (n=2), hepato-billiary (n=2), prostate (n=3), skin (n=5), and unknown primary (n=1). SMN incidence was higher with increasing follow-up (2002-2014, 8%; 2015-2017, 2.8%, 2018-2019, 0%, p=0.002). There was no association with development of SMN and gender, age at transplant, type of stem cell source or transplant conditioning. Incidence of SMN was significantly higher for all sites as compared to general population. Cumulative incidence of SMN was 5% at 5 yr, and 15% at 10 yr for AutoSCT patients.Conclusion: Myeloma patients are at increased risk of SMN and need monitoring for long term side effects. Development of MDS post AutoSCT is the commonest SMN post AutoSCT but there is increased incidence of solid tumours as well. Impact of new modalities of treatment needs long term monitoring. DisclosuresBloor: Novartis: Honoraria; Kite, a Gilead Company: Honoraria.

A Systematic Review on Intensity Modulated Radiation Therapy for Mediastinal Hodgkin's Lymphoma.

Secondary malignant neoplasms (SMNs) and cardiovascular diseases induced by chemotherapy and radiotherapy represent the main cause of excess mortality for early-stage Hodgkin lymphoma patients, especially when the mediastinum is involved. Conformal radiotherapy techniques such as Intensity-Modulated Radiation Therapy (IMRT) could allow a reduction of the dose to the organs-at-risk (OARs) and therefore limit long-term toxicity. We performed a systematic review of the current literature regarding comparisons between IMRT and conventional photon beam radiotherapy, or between different IMRT techniques, for the treatment of mediastinal lymphoma. IMRT allows a substantial reduction of the volumes of OARs exposed to high doses, reducing the risk of long-term toxicity. This benefit is conterbalanced by the increase of volumes receiving low doses, that could potentially increase the risk of SMNs. Treatment planning should be personalized on patient and disease characteristics. Dedicated techniques such as "butterfly" VMAT often provide the best trade-off.