Deep-Learning for Rapid Estimation of the Out-of-Field Dose in External Beam Photon Radiation Therapy - A Proof of Concept

PURPOSE

The dose deposited outside of the treatment field during external photon beam radiation therapy treatment, also known as out-of-field dose, is the subject of extensive study as it may be associated with a higher risk of developing a second cancer and could have deleterious effects on the immune system that compromise the efficiency of combined radio-immunotherapy treatments. Out-of-field dose estimation tools developed today in research, including Monte Carlo simulations and analytical methods, are not suited to the requirements of clinical implementation because of their lack of versatility and their cumbersome application. We propose a proof of concept based on deep learning for out-of-field dose map estimation that addresses these limitations.

METHODS AND MATERIALS

For this purpose, a 3D U-Net, considering as inputs the in-field dose, as computed by the treatment planning system, and the patient's anatomy, was trained to predict out-of-field dose maps. The cohort used for learning and performance evaluation included 3151 pediatric patients from the FCCSS database, treated in 5 clinical centers, whose whole-body dose maps were previously estimated with an empirical analytical method. The test set, composed of 433 patients, was split into 5 subdata sets, each containing patients treated with devices unseen during the training phase. Root mean square deviation evaluated only on nonzero voxels located in the out-of-field areas was computed as performance metric.

RESULTS

Root mean square deviations of 0.28 and 0.41 cGy/Gy were obtained for the training and validation data sets, respectively. Values of 0.27, 0.26, 0.28, 0.30, and 0.45 cGy/Gy were achieved for the 6 MV linear accelerator, 16 MV linear accelerator, Alcyon cobalt irradiator, Mobiletron cobalt irradiator, and betatron device test sets, respectively.

CONCLUSIONS

This proof-of-concept approach using a convolutional neural network has demonstrated unprecedented generalizability for this task, although it remains limited, and brings us closer to an implementation compatible with clinical routine.

Very long-term outcomes of pediatric patients treated for optic pathway gliomas: A longitudinal cohort study

BACKGROUND

Optic pathway gliomas (OPG) represent 5% of childhood brain tumors. Successive relapses lead to multiple treatments exposing to late complications.

METHODS

We included patients treated at Gustave Roussy (GR) between 01.1980 and 12.2015 for OPG, before 18 years-old and alive at 5 years from diagnosis. Mortality and physical health conditions data were extracted from medical data files and updated thanks to the GR long-term follow-up program and French national mortality registry for patients included in the French Childhood Cancer Survivor Study.

RESULTS

We included 182 5y-OPG-childhood survivors in the analysis (sex-ratio M/F 0.8, 35% with NF1). With a median follow-up of 17.2y (range=5-41), we registered 82 relapses, 9 second malignancies and 15 deaths as first events after 5 years, resulting in 20-y conditional overall survival (C-OS) and late events-free survival (LEFS) of 79.9% (95%CI=71-86) and 43.5% (95%CI=36-51) respectively. NF1 (Hazard ratio HR=3, 95%CI=1.4-6.8), hypothalamic involvement (HR=3.2, 95%CI=1.4-7.3), and radiotherapy (HR=2.8, 95%CI=1.1-6.7) were significantly associated with C-OS in multivariable analyses. Ninety-five percent of 5y-OPG survivors suffered from any health condition, especially visual acuity "<1/10" (n=109), pituitary deficiency (n=106) and neurocognitive impairment (n=89). NF1 (HR 2.1) was associated with precocious puberty. With a median time post diagnosis of 4.2 years, 33 cerebrovascular events were observed in 21 patients.

CONCLUSION

Late relapses, second malignancies and cerebrovascular diseases are severe late events resulting in premature mortality. Morbidity is high and needing after-cancer care to improve quality of life. Risk factors could be considered to better stratify long-term follow-up.

Predictive factors of long-term follow-up attendance in very long-term childhood cancer survivors

BACKGROUND

Long-term follow-up (LTFU) clinics have been developed but only some childhood cancer survivors (CCS) attend long-term follow-up (LTFU).

OBJECTIVE

To identify factors that influence LTFU attendance.

METHODS

Five-year CCS treated for a solid tumor or lymphoma in Gustave Roussy before 2000, included in the FCCSS cohort (French Childhood Cancer Survivor Study), aged >18 years and alive at the date of the LTFU Clinic opening (January 2012) were invited to a LTFU visit. Factors associated with attendance at the LTFU clinic between 2012 and 2020 were estimated using logistic regression analyses. Analyses included different types of factors: clinical (tumor characteristics, cancer treatments, late effects), medical (medical expenses were used as a proxy of survivor's health status), social (deprivation index based on census-tract data relating to income, educational level, proportion of blue-collar workers, and unemployed people living in the area of residence), and spatial (distance to the LTFU clinic).

RESULTS

Among 2341 CCS contacted (55% males, mean age at study, 45 years; SD ± 10 years; mean age at diagnosis, 6 years; SD ± 5 years), 779 (33%) attended at least one LTFU visit. Initial cancer-related factors associated with LTFU visit attendance were: treatment with both radiotherapy and chemotherapy (odds ratio [OR], 4.02; 95% CI, 2.11-7.70), bone sarcoma (OR, 2.43; 95% CI, 1.56-3.78), central nervous system primitive tumor (OR, 1.65; 95% CI, 1.02-2.67), and autologous hematopoietic cell transplant (OR, 2.07; 95% CI, 1.34-3.20). Late effects (OR, 1.70; 95% CI, 1.31-2.20), highest medical expenses (OR, 1.65; 95% CI, 1.22-2.22), living in the most advantaged area (OR vs. the most deprived area = 1.60; 95% CI, 1.15-2.22), and shorter distance from LTFU care center (<12 miles) also increased attendance.

CONCLUSIONS

Patients who are apparently healthy as well as socially disadvantaged and living far away from the center are less likely to attend LTFU care.

PLAIN LANGUAGE SUMMARY

Among 2341 adult childhood cancer survivors contacted between 2012 and 2020, 33% attended at least one long-term follow-up visit. Clinical factors related to attendance were multimodal treatment of first cancer (combining chemotherapy and radiotherapy), stem cell transplant, type of diagnosis (bone tumor and central nervous system primitive tumor), late effects (at least one disease among second malignancy, heart disease, or stroke), and highest medical expenses. In addition, the study identified social and spatial inequalities related to attendance, with independent negative effects of distance and social deprivation on attendance, even though the medical costs related to the long-term follow-up examinations are covered by the French social security system.

Early Development of Atherosclerotic Plaques in the Coronary Arteries after Radiotherapy for Breast Cancer (BACCARAT Study)

Background-Radiotherapy (RT) for breast cancer (BC) can lead to an increased risk of coronary artery disease several years after RT. The aim of this study was to evaluate the development of overall, non-calcified and calcified atherosclerotic plaques over 2 years after BC for RT and associations with cardiac exposure. Methods-The study included 101 left- or right-sided BC patients treated with RT without chemotherapy. A coronary CT angiography was performed before and 2 years after RT. Plaque development thorough the entire coronary network was defined as an increased number of plaques. Cardiac exposure was quantified with mean doses to the heart, left ventricle, and coronary arteries. Logistic regression models were used to assess association with doses. Results-At inclusion, 37% of patients had plaques, increasing to 42% two years after RT. Overall plaque development was observed in seven patients: five with calcified plaque development and four with non-calcified plaque development. The risk of overall plaque development was significantly associated with doses to the Left Main and Circumflex coronary arteries (OR at 1 Gy = 2.32, p = 0.03 and OR at 1 Gy = 2.27, p = 0.03, respectively). Specific analyses for calcified and non-calcified plaque development showed similar results. Conclusion-Our study suggests an association between coronary arteries exposure and the risk of developing both calcified and non-calcified atherosclerotic plaques over 2 years after BC RT. Trial registration number: NCT02605512.

Risk factors for obesity in adulthood among survivors of childhood cancer

OBJECTIVE

The aim of this study was to identify risk factors for obesity in childhood cancer survivors (CCSs).

METHODS

The study included 3199 patients of the French Childhood Cancer Survivor Study cohort, with 303 patients with obesity who had returned the self-questionnaire. Analyses were adjusted for social deprivation index and sex.

RESULTS

CCSs were less likely to have obesity (9.5%; 95% CI: 8.5%-10.5%) than expected from the general French population rates (12.5%; p = 0.0001). Nevertheless, brain tumor survivors were significantly more likely to develop obesity than the general French population (p = 0.0001). Compared with patients who did not receive radiotherapy to the pituitary gland, those who received a dose >5 Gy had an increased risk of obesity: relative risk 1.9 (95% CI: 1.2-3.1), 2.5 (95% CI: 1.7-3.7), and 2.6 (95% CI: 1.6-4.3), respectively, for participants with 6 to 20 Gy, 20 to 40 Gy, and ≥40 Gy of radiation. Etoposide administration significantly increased the risk of obesity (relative risk 1.7; 95% CI: 1.1-2.6). High social deprivation index was also a risk factor, just like BMI at diagnosis.

CONCLUSIONS

Long-term follow-up of CCSs should include weight follow-up during adulthood.

Dosiomics-Based Prediction of Radiation-Induced Valvulopathy after Childhood Cancer

Valvular Heart Disease (VHD) is a known late complication of radiotherapy for childhood cancer (CC), and identifying high-risk survivors correctly remains a challenge. This paper focuses on the distribution of the radiation dose absorbed by heart tissues. We propose that a dosiomics signature could provide insight into the spatial characteristics of the heart dose associated with a VHD, beyond the already-established risk induced by high doses. We analyzed data from the 7670 survivors of the French Childhood Cancer Survivors' Study (FCCSS), 3902 of whom were treated with radiotherapy. In all, 63 (1.6%) survivors that had been treated with radiotherapy experienced a VHD, and 57 of them had heterogeneous heart doses. From the heart-dose distribution of each survivor, we extracted 93 first-order and spatial dosiomics features. We trained random forest algorithms adapted for imbalanced classification and evaluated their predictive performance compared to the performance of standard mean heart dose (MHD)-based models. Sensitivity analyses were also conducted for sub-populations of survivors with spatially heterogeneous heart doses. Our results suggest that MHD and dosiomics-based models performed equally well globally in our cohort and that, when considering the sub-population having received a spatially heterogeneous dose distribution, the predictive capability of the models is significantly improved by the use of the dosiomics features. If these findings are further validated, the dosiomics signature may be incorporated into machine learning algorithms for radiation-induced VHD risk assessment and, in turn, into the personalized refinement of follow-up guidelines.

Assessment of Differentiated Thyroid Carcinomas in French Polynesia After Atmospheric Nuclear Tests Performed by France

Importance

Due to the amount of iodine 131 released in nuclear tests and its active uptake by the thyroid, differentiated thyroid carcinoma (DTC) is the most serious health risk for the population living near sites of nuclear tests. Whether low doses to the thyroid from nuclear fallout are associated with increased risk of thyroid cancer remains a controversial issue in medicine and public health, and a misunderstanding of this issue may be associated with overdiagnosis of DTCs.

Design, Setting, and Participants

This case-control study was conducted by extending a case-control study published in 2010 that included DTCs diagnosed between 1984 and 2003 by adding DTCs diagnosed between 2004 and 2016 and improving the dose assessment methodology. Data on 41 atmospheric nuclear tests conducted by France between 1966 and 1974 in French Polynesia (FP) were assessed from original internal radiation-protection reports, which the French military declassified in 2013 and which included measurements in soil, air, water, milk, and food in all FP archipelagos. These original reports led to an upward reassessment of the nuclear fallout from the tests and a doubling of estimates of the mean thyroid radiation dose received by inhabitants from 2 mGy to nearly 5 mGy. Included patients were diagnosed from 1984 to 2016 with DTC at age 55 years or younger and were born in and resided in FP at diagnosis; 395 of 457 eligible cases were included, and up to 2 controls per case nearest by birthdate and matched on sex were identified from the FP birth registry. Data were analyzed from March 2019 through October 2021.

Exposure

The radiation dose to the thyroid gland was estimated using recently declassified original radiation-protection service reports, meteorological reports, self-reported lifestyle information, and group interviews of key informants and female individuals who had children at the time of these tests.

Main Outcomes and Measures

The lifetime risk of DTC based on Biological Effects of Ionizing Radiation (BEIR) VII models was estimated.

Results

A total of 395 DTC cases (336 females [85.1%]; mean [SD] age at end of follow-up, 43.6 [12.9] years) and 555 controls (473 females [85.2%]; mean [SD] age at end of follow-up, 42.3 [12.5] years) were included. No association was found between thyroid radiation dose received before age 15 years and risk of DTC (excess relative risk [ERR] per milligray, 0.04; 95% CI, -0.09 to 0.17; P = .27). When excluding unifocal noninvasive microcarcinomas, the dose response was significant (ERR per milligray, 0.09; 95% CI, -0.03 to 0.02; P = .02), but several incoherencies with the results of the initial study reduce the credibility of this result. The lifetime risk for the entire FP population was 29 cases of DTC (95% CI, 8-97 cases), or 2.3% (95% CI, 0.6%-7.7%) of 1524 sporadic DTC cases in this population.

Conclusions and Relevance

This case-control study found that French nuclear tests were associated with an increase in lifetime risk of PTC in FP residents of 29 cases of PTC. This finding suggests that the number of thyroid cancer cases and the true order of magnitude of health outcomes associated with these nuclear tests were small, which may reassure populations of this Pacific territory.

CANTO-RT: One of the Largest Prospective Multicenter Cohort of Early Breast Cancer Patients Treated with Radiotherapy including Full DICOM RT Data

This article describes the methodology used and provides a characterization of the study population in CANTO-RT (CANcer TOxicities RadioTherapy). CANTO (NCT01993498) is a prospective clinical cohort study including patients with stage I-III BC from 26 French cancer centers. Patients matching all CANTO inclusion and exclusion criteria who received RT in one of the 10 top recruiting CANTO centers were selected. Individual full DICOM RT files were collected, pseudo-anonymized, structured and analyzed on the CANTO-RT/UNITRAD web platform. CANTO-RT included 3875 BC patients with a median follow-up of 64 months. Among the 3797 patients with unilateral RT, 3065 (80.4%) had breast-conserving surgery, and 2712 (71.5%) had sentinel node surgery. Tumor bed boost was delivered in 2658 patients (68.5%) and lymph node RT in 1356 patients (35%), including internal mammary chain in 844 patients (21.8%). Most patients (3691 (95.3%)) were treated with 3D conformal RT. Target volumes, organs at risk contours and dose/volume histograms were extracted after quality-control procedures. CANTO-RT is one of the largest early BC prospective cohorts with full individual clinical, biological, imaging and DICOM RT data available. It is a valuable resource for the identification and validation of clinical and dosimetric predictive factors of RT and multimodal treatment-related toxicities.

Breast cancer risk among thyroid cancer survivors and the role of I-131 treatment

BACKGROUND

Female thyroid cancer survivors are more likely to have a higher risk of breast cancer compared to the general population, and the underlying causes are yet to be understood. The potential role of I-131 treatment on this association remains controversial.

METHODS

We pooled individual data of women who were treated for differentiated thyroid cancer from 1934 to 2005 in France, Italy and Sweden. Standardized incidence ratios (SIRs) for breast cancer were estimated by comparison with age, sex and calendar-year expected values of the general population in each country. We estimated breast cancer risk in relation to I-131 treatment using time-dependent Poisson models.

RESULTS

Of 8475 women (mean age at diagnosis: 45 years, range 2-90 years), 335 were diagnosed with breast cancer [SIR = 1.52, 95% confidence interval (CI): 1.36-1.69] during a median follow-up time of 12.7 years since diagnosis. Overall, breast cancer risk did not differ between women treated or not with I-131 (relative risk=1.07, 95% CI 0.84-1.35). However, breast cancer risk increased with increasing cumulative I-131 activity, without significant departure from linearity (excess relative risk per 100 mCi=17%, 95% CI: 2% to 38%). The higher risk associated with a cumulative I-131 activity of ≥100 mCi and ≥400 mCi was translated into 4 (95% CI -4 to 13) and 42 (95% CI -8 to 93) excess breast cancer cases per 10,000 person-years, respectively.

CONCLUSIONS

An elevated risk was observed for the highest cumulative administered activity (>=400 mCi), and a significant dose-dependent association was observed among thyroid cancer survivors who were treated with I-131. However, overall, I-131 treatment might only explain partly the increase in breast cancer risk among female thyroid cancer survivors.

Early Coronary Artery Calcification Progression over Two Years in Breast Cancer Patients Treated with Radiation Therapy: Association with Cardiac Exposure (BACCARAT Study)

Background: Radiotherapy (RT) for breast cancer (BC) can induce coronary artery disease many years after RT. At an earlier stage, during the first two years after RT, we aimed to evaluate the occurrence of increased coronary artery calcium (CAC) and its association with cardiac exposure. Methods: This prospective study included 101 BC patients treated with RT without chemotherapy. Based on CAC CT scans performed before and two years after RT, the event ‘CAC progression’ was defined by an increase in overall CAC score (CAC RT+ two years—CAC before RT > 0). Dosimetry was evaluated for whole heart, left ventricle (LV), and coronary arteries. Multivariable logistic regression models were used to assess association with doses. Results: Two years after RT, 28 patients presented the event ‘CAC progression’, explained in 93% of cases by a higher CAC score in the left anterior descending coronary (LAD). A dose−response relationship was observed with LV exposure (for Dmean LV: OR = 1.15, p = 0.04). LAD exposure marginally explained increased CAC in the LAD (for D2 LV: OR =1.03, p = 0.07). Conclusion: The risk of early CAC progression may be associated with LV exposure. This progression might primarily be a consequence of CAC increase in the LAD and its exposure.

The Psychological Consequences of the COVID-19 Pandemic in Adults Treated for Childhood Cancer

Background: Compared with the general population, childhood cancer survivors (CCS) could be at greater risk of psychological distress following the emergence of the COVID-19 pandemic. Purpose: This cross-sectional study assessed the psychological consequences of COVID-19 on the mental health of CCS. Design and participants: In December 2020, we interviewed through an online self-report questionnaire, 580 5-year CCS participating in the French Childhood Cancer Survivor Study (FCCSS) cohort. Methods: We first compared the mental health score of CCS with that observed in the French general population of the same age and gender. Subsequently, we studied predictors of the mental health score of CCS. Results: External comparisons revealed that the mental health score of CCS was similar to that of the general population. Among CCS, almost 42% stated that their psychological state had been worse during the lockdown. Predictors of poorer mental health included, among others, female gender, reporting a change in the occupational situation, having a relative who had been hospitalized or had died following COVID-19, and a greater perceived infection risk. Interpretation and Implications: Given the pre-existing vulnerability of some CCS to mental distress, the additional psychological consequences of COVID-19 in vulnerable survivors should receive attention from health care providers.

Risk perceptions and health care use in the era of the COVID-19 pandemic in adults treated for childhood cancer

Purpose

During the COVID-19 pandemic, childhood cancer survivors (CCS) may have felt more at risk of having severe consequences of COVID-19 and therefore may have been more likely to defer their health care use. We aimed to assess the risk perceptions of CCS related to COVID-19 (perceived infection risk, perceived risk of experiencing a severe illness in the event of infection), and their forgoing of health care during the year 2020.

Methods

In December 2020, we interviewed through an online self-report questionnaire 580 5-year CCS participating in the French Childhood Cancer Survivor Study (FCCSS) cohort. Combining clinical and patient-reported outcomes, we studied predictors of perceived risks related to COVID-19 and forgoing health care.

Results

Overall, 60% of respondents stated that COVID-19 could have severe consequences for their health if infected. Survivors with a cardiovascular disease and those who felt more at risk of being infected were more likely to think that COVID-19 could have severe health consequences for them. Moreover, 30% of respondents seeking care declared they had forgone at least one medical appointment in 2020. Forgoing medical appointments was more common among CCS who reported a deterioration in their financial situation in 2020 and those who felt more at risk of being infected.

Conclusions

This study shows that a considerable proportion of survivors had forgone medical appointments because of the pandemic; forgoing care was more frequent among the most socioeconomically disadvantaged survivors.

Implications for cancer survivors.

This study presents data hitherto absent in the literature and suggests the need to develop telehealth to ensure appropriate long-term follow-up of CCS.

Abstract P3-19-01: CANTO RT: The largest prospective multicenter cohort of early breast cancer patients treated with radiotherapy including full DICOM RT data

Purpose: In this paper, we describe the methodology used, and provide a first characterization of the study population and radiotherapy (RT) data in CANTO-RT (CANcer TOxicities Radiotherapy), the largest available multicenter prospective cohort of early breast cancer (BC) patients treated with RT that aims to identify predictors of development, and persistence of long-term toxicities. Methods: CANTO (NCT01993498) is a French prospective clinical cohort study of 10 150 patients with stage I-III BC from 26 cancer centers. Patients matching all CANTO inclusion and exclusion criteria, who received RT and were still in follow up, in the 10 top recruiting CANTO centers, with a minimum follow up of 3 years, were selected for CANTO-RT. Eligible patients had breast/chest wall +/- lymph node RT with curative intent. Individual full DICOM RT files (CT, RT Structure, RT Dose, RT Plan) were collected, anonymized, structured and analyzed on the CANTO-RT/UNITRAD web platform using AQUILAB Share Place™ and Analytics Dose module. Characteristics of the patients and tumors (including TNM, histology, HER2, estrogen and progesterone receptor) were recorded at baseline. Characteristics of the treatments, skin, lung, cardiovascular, neurological, musculoskeletal toxicities (CTCAE v4.0), QOL (BR23, QLQC30), cosmetic, and oncological outcomes were assessed at diagnosis (baseline), 3-6 (M0), 12 (M12), 36 (M36) and 60 (M60) months after completion of primary surgery, chemotherapy or radiotherapy whichever came last together, with blood, plasma and serum tests. Results: CANTO-RT enrolled 3875 BC patients between June 2012 and February 2017 with a median follow-up of 64 months :1947 (50.2%) left side, 1850 (47.8%) right side and 78 (2%) bilateral BC. The vast majority of patients had hormone receptor-positive tumors 3321 (85.7%) and 553 (14.3%) had human epidermal growth factor 2 (HER2) positive tumors; 2586 (66.7%) had stage pT1 and 2525 (65.2%) pN0 disease; 2087 (53.8%) neoadjuvant or adjuvant chemotherapy, 477 (12.3%) adjuvant trastuzumab and 3138 (81%) adjuvant endocrine therapy. Among 3797 patients with unilateral RT, 3065 (80.4%) had breast conserving surgery, 747 (19.6%) total mastectomy; 2712 (71.5%) sentinel node and 1080 (28.5%) axillary dissection. Tumor bed boost was delivered in 2658 patients (68.5%) and lymph node RT in 1356 patients (35%) including internal mammary chain in 844 patients (21.8%). Most patients 3691 (95.3%) were treated with 3D conformal RT and 184 (4.7%) with intensity-modulated RT. Normofractionated RT (2Gy/fraction) was mostly used (69.9%). Clinical target (breast, chest wall, lymph nodes) and contoured organs at risk (heart, left anterior descending coronary, lung, spinal cord, esophagus, thyroid, brachial plexus, contralateral breast, humeral head) contours and dose/volume histograms were automatically extracted after quality control procedure excluding corrupted files and inconsistencies 36 (1%) (Table 1). Conclusion: CANTO-RT is the largest early breast cancer prospective cohort with full individual clinical and DICOM RT data available. CANTO-RT is a valuable resource, open for collaborative projects, for identification and validation of clinical and dosimetric predictive factors of RT related toxicities. Further long term follow up is ongoing.

Table 1.Baseline characteristics of the CANTO RT breast cancer patients.CharacteristicsBreast Cancer Patients [N(%) or Mean (range)]Age at enrolmentMean (range), years56.5 (23.3-85.8)Tumour size (pT)T037 (1)T12586 (66.7)T21058 (27.3)T3177 (4.6)Missing17 (0.4)Nodal status (pN)02525 (65.2)11035 (26.7)2223 (5.8)379 (2)Missing13 (0.3)Tumour histologyInfiltrating Ductal3011 (77.7)Lobular473 (12.2)Others (including mixed)381 (9.8)Missing10 (0.3)Hormone Receptors positiveNegative541 (14)Positive3321 (85.7)Missing13 (0.3)HER2Negative3305 (85.3)Positive553 (14.3)Missing17 (0.4)Type of chemotherapyNo chemotherapy1788 (46.1)Neoadjuvant chemotherapy450 (11.6)Adjuvant chemotherapy1629 (42)Peri-adjuvant chemotherapy (neo + adjuvant)8 (0.2)Hormonal therapyNo730 (18.8)Yes3138 (81)Missing7 (0.2)Herceptin treatmentNo or Not applicable3378 (87.2)Yes477 (12.3)Missing20 (0.5)Type of breast surgerylumpectomy3113 (80.3)Mastectomy734 (18.9)Right lumpectomy and Left mastectomy13 (0.3)Right mastectomy and Left lumpectomy9 (0.2)None6 (0.2)Type of lymph node surgerySentinel node2746 (70.9)Axillary dissection1086 (28)Right sentinel node, Left axillary dissection20 (0.5)Right axillary dissection, left sentinel node12 (0.3)None11 (0.3)Radiation therapyRight Side1850 (47.8)Left Side1947 (50.2)Bilateral78 (2.0)Patients with boostNo or Not applicable1217 (31.4)Yes2658 (68.6)Lymph node levels treatedNone2519 (65)Yes1356 (35)Level 1284 (20.9)Level 2340 (25.1)Level 31072 (79.1)Level 41348 (99.4)Internal mammary chain844 (62.2)Irradiation techniques3D3691 (95.3)IMRT184 (4.7)Fractionation regimensNormofractionation 25-fractions2707 (69.9)Hypofractionation 15-16 fractions166 (4.3)Hypofractionation and Partial breast irradiation51 (1.3)Unspecified fractionation - CTV breast or chest wall not delineated951 (24.5)

Citation Format: Thomas Sarrade, Rodrigue Allodji, Youssef Ghannam, Guillaume Auzac, Sibille Everhard, Ophélie Querel, Youlia Kirova, Karine Peignaux, Philippe Guilbert, Claire Charra-Brunaud, Julien Blanchecotte, Rezart Belshi, David Pasquier, Séverine Racadot, Céline Bourgier, Sandrine Ducornet, David Gibon, Fabrice André, Florent De Vathaire, Sofia Rivera. CANTO RT: The largest prospective multicenter cohort of early breast cancer patients treated with radiotherapy including full DICOM RT data [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-19-01.

Topographic variability of the normal circle of Willis anatomy on a paediatric population

Long-term sequelae are major limitations of radiation therapy use, especially for childhood brain tumour. Circle of Willis irradiation strongly increases the long-term risk of stroke, but to establish dose-response relationship, anticipating long-term effects of new techniques, requires to perform accurate and reproducible dosimetric estimations in large cohorts of patients having received radiotherapy decades ago. For the accuracy of retrospective dose reconstruction, the topographic variability of the Circle of Willis arteries is crucial. In order to improve retrospective dosimetric studies and dose-volume estimates to the typical Circle of Willis arteries, we aim to study the inter-individual topographic variability of these structures. Thirty-eight time of flight MRI sequences of children aged 2–17 years in both genders were investigated. A region growth algorithm was used for the segmentation of the cerebral arteries. A rigid registration in a common skull was performed following the anatomy of skull base foramina. The Posterior clinoid processes of the sella turcica were used as reference landmark (R0), and 5 key landmarks were chosen in each segmented Circle of Willis, then distances between the 5 landmarks and R0 were calculated for each of the 38 subjects. The distance between R0 and each landmark of the Circle of Willis followed a normal distribution, the average values ranging from 13.6 to 17.0 mm, and the standard deviations ranged from 2.6 to 3.0 mm, i.e. less than a fifth of the average value. The perimeter of the Circle of Willis was longer in older subjects, this increase being isotropic. Our study shows a remarkably low topographic variability of the typical Circle of Willis. An important result, allowing reliable anthropomorphic phantoms-based retrospective estimations of the radiation doses delivered to these arterial structures during radiotherapy treatment.

New insights in cisplatin and radiation-induced ototoxicity: A French Childhood Cancer Survivors Study (FCCSS)

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Background: Platinum chemotherapy (CT) and cranial radiotherapy (RT) are risk factors of ototoxicity. Effects of RT dose at inner ear and of other CT were investigated. Methods: Of 7670 5-year childhood cancer survivors from the FCCSS treated before 20 years of age in 1942-2000 for solid cancer or lymphoma, 5243 with ototoxicity long-term follow-up data were included. Severe ototoxicity, defined as the need of hearing aids or Brock grade 3-4 hearing loss, was identified from self-administrated questionnaires, clinical visits and cohort linkage with the French Hospital Database and health insurance information system (SNIIRAM). The mean RT dose at inner ear was estimated using home-made software. Multivariable Cox models adjusted for gender, age at diagnosis, time period and social deprivation index was used to identify risk factors for severe ototoxicity. Results: After a mean follow-up of 30 years, 199 cases of severe ototoxicity were identified. Cumulative incidences at 30 and 50 years of age (30,50y-CumInc) were, 2.8% (95%CI = 2.4-3.3) and 5.5% (4.6-6.5), respectively. Mean RT dose at inner ear (Hazard Ratio HR = 1.6 (95%CI = 1.0-2.5), 4.5 (2.7-7.2), 5.7 (3.0-10.8) and 14.0 (9.2-21.2) for 0- < 5, 5- < 30, 30- < 40 and ≥40 Gy), as well as cisplatin (HR = 2.8, 95%CI = 1.9-4.0), melphalan (HR = 3.3, 95%CI = 1.9-5.7) and busulfan exposure (HR = 2.6, 95%CI = 1.6-4.4) were significantly associated with severe ototoxicity. Concerning melphalan (n = 199/5243 exposed), almost all cases were identified in neuroblostma patients (NBL), who also received cisplatin 200mg/m²/cycle (26/92 NBL, 30y-CumInc = 36.4% (95%CI = 25.9-48.4), vs. 3/107 non-NBL, 30y-CumInc = 1.6% (0.4-5.6)). Concerning busulfan (n = 131/5243 exposed), all cases were identified in NBL (n = 16/63, all treated with melphalan and cisplatin) and brain tumors (n = 13/28, all with RT at inner ear ≥5Gy). The 30y-CumInc in patients with RT at inner ear ≥5Gy was 7.4% (95%CI = 5.7-9.6) and 39.8% (22.5-60.0) respectively with and without busulfan. Conclusions: RT at inner ear has significant deleterious impact on audition, with cumulative incidence still worsening > 30years after RT, and with likely potentiation by busulfan. The deleterious effect of melphalan was related to previous treatment with cisplatin, either by interaction between these drugs, or by the high cisplatin dose by cycle used in NBL.

Leukaemia and myeloid malignancy among people exposed to low doses (<100 mSv) of ionising radiation during childhood: a pooled analysis of nine historical cohort studies

BACKGROUND

Substantial evidence links exposure to moderate or high doses of ionising radiation, particularly in childhood, with increased risk of leukaemia. The association of leukaemia with exposure to low-dose (<100 mSv) radiation is less certain, although this is the dose range most relevant to the general population. We aimed to estimate the risk of leukaemia associated with low-dose radiation exposure in childhood (age <21 years).

METHODS

In this analysis of historical cohort studies, we pooled eligible cohorts reported up to June 30, 2014. We evaluated leukaemia and myeloid malignancy outcomes in these cohorts with the relevant International Classification of Diseases and International Classification of Diseases for Oncology definitions. The cohorts included had not been treated for malignant disease, had reported at least five cases of the relevant haematopoietic neoplasms, and estimated individual active bone marrow (ABM) doses. We restricted analysis to individuals who were younger than 21 years at first irradiation who had mean cumulative ABM doses of less than 100 mSv. Dose-response models were fitted by use of Poisson regression. The data were received in fully anonymised form by the statistical analyst.

FINDINGS

We identified nine eligible cohorts from Canada, France, Japan, Sweden, the UK, and the USA, including 262 573 people who had been exposed to less than 100 mSv enrolled between June 4, 1915, and Dec 31, 2004. Mean follow-up was 19·63 years (SD 17·75) and mean cumulative ABM dose was 19·6 mSv (SD 22·7). 154 myeloid malignancies were identified (which included 79 acute myeloid leukaemias, eight myelodysplastic syndromes, and 36 chronic myeloid leukaemias, in addition to other unspecified myeloid malignancies) and 40 acute lymphoblastic leukaemias, with 221 leukaemias (including otherwise unclassified leukaemias but excluding chronic lymphocytic leukaemia) identified overall. The fitted relative risks at 100 mSv were 3·09 (95% CI 1·41-5·92; p_trend=0·008) for acute myeloid leukaemia and myelodysplastic syndromes combined, 2·56 (1·09-5·06; p_trend=0·033) for acute myeloid leukaemia, and 5·66 (1·35-19·71; p_trend=0·023) for acute lymphoblastic leukaemia. There was no clear dose-response for chronic myeloid leukaemia, which had a relative risk at 100 mSv of 0·36 (0·00-2·36; p_trend=0·394). There were few indications of between-cohort heterogeneity or departure from linearity. For acute myeloid leukaemia and myelodysplastic syndromes combined and for acute lymphoblastic leukaemia, the dose-responses remained significant for doses of less than 50 mSv. Excess absolute risks at 100 mSv were in the range of 0·1-0·4 cases or deaths per 10 000 person-years.

INTERPRETATION

The risks of acute myeloid leukaemia and acute lymphoblastic leukaemia were significantly increased after cumulative doses of ionising radiation of less than 100 mSv in childhood or adolescence, with an excess risk also apparent for cumulative radiation doses of less than 50 mSv for some endpoints. These findings support an increased risk of leukaemia associated with low-dose exposure to radiation and imply that the current system of radiological protection is prudent and not overly protective.

FUNDING

National Cancer Institute Intramural Research Program, National Cancer Institute, and US National Institutes for Health.

Clinical and histological features of second breast cancers following radiotherapy for childhood and young adult malignancy

OBJECTIVE

The purpose of this study was to determine the characteristics of early second breast cancer (SBC) among survivors of childhood and young adult malignancy treated with irradiation.

METHODS

We conducted a multicenter retrospective study of women who presented with breast cancer aged 50 years or younger in nine French centers.

RESULTS

121 patients and 141 SBC were analyzed (invasive = 130; non-invasive = 11). The mean age at first cancer diagnosis was 15 years and at initial SBC diagnosis was 38 years. Bilateral disease before the age of 51 years was diagnosed in 16% of the females. The majority of SBC were invasive carcinomas (92%). Among the invasive carcinomas, 39% had a histoprognostic score of III, 3.1% overexpressed HER2 and 29% were triple negative. The proportion of triple negative phenotype SBC was higher in patients older at first cancer diagnosis [RR = 1.2, 95% CI (1.1-1.3)]. 94% of triple negative SBCs developed in breast tissue which had received >20 Gy.

CONCLUSION

We found a high proportion of aggressive SBC following thoracic radiotherapy in childhood or early adulthood. Advances in knowledge: SBC screening is recommended by scientific societies for these child/young-adulthood cancer survivors in the same way as the one for high risk women because of constitutional mutations. Our results support these recommendations, not only because of a similar cumulative risk, but also because of the aggressive histological characteristics.

The right to be forgotten: a change in access to insurance and loans after childhood cancer?

PURPOSE

Access to insurance for a loan or a mortgage is an important issue for childhood cancer survivors. The aim of this study was to describe difficulties experienced by adult survivors.

METHODS

A total of 1920 survivors treated before the age of 18 in five French cancer centers responded to a questionnaire in 2010. Survivors who had tried to obtain a loan were asked if they had experienced difficulties, which were defined as experiencing rejection, higher premiums, or exclusions. The questionnaire investigated health problems related to the circulatory, respiratory, digestive, urinary, endocrine, hormonal, and nervous systems. Second tumors, diabetes mellitus, cardiac disease, and stroke were ascertained from a physician's report or medical records. Multivariable analyses were conducted to identify the characteristics of survivors reporting difficulties.

RESULTS

Difficulties were experienced by 10.4% of those who had tried to obtain a small loan (n = 787) and by 30.1% of those who had tried to obtain a home loan (n = 909). Disclosure of childhood cancer to the insurer and amputation surgery were negatively associated with insurance accessibility, even when controlling for age, gender, education, health-related unemployment, familial situation, and severe or life-threatening conditions such as cardiovascular diseases, second cancers, or diabetes.

CONCLUSION

This study showed that the financial burden of cancer can extend decades after diagnosis.

IMPLICATIONS FOR CANCER SURVIVORS

Thanks to a 2016 law, French cancer survivors no longer have to disclose their cancer to insurers after a fixed number of years. This law will probably lessen the socioeconomic burden of cancer.

Screening for psychological distress in very long-term adult survivors of childhood cancer

This study evaluated the prevalence of psychological distress (PD) in a cohort of 348 adult childhood cancer survivors with a very long-term follow-up and assessed the characteristics associated with this distress (cancer type, treatment, sex, age at diagnosis, self-reported late effects, social support, type of remembrance, time since the diagnosis, age at evaluation), assuming that with time since the diagnosis, the PD of survivors will approximate that of the general population. Before attending a long-term follow-up consultation, survivors were sent 3 questionnaires: the Brief Symptom Inventory-18, the Impact of Event Scale, and the Illness Worry Scale (IWS). During the visit, they were administered the Mini-International Neuropsychiatric Interview (MINI) by a psychologist. The mean age of the survivors was 38.5 years (18.1-65.8) at consultation, 7 years (0.0-18.0) at cancer diagnosis, and mean time since diagnosis was 31.5 years (8.8-56.1). Multiple regression analyses of the data collected from self-administered questionnaires confirmed that being female, living alone, and self-reported late effects were associated with the high scores for all scales. Negative remembrances and being accompanied to the clinic were associated with higher IWS scores. Unlike the initial hypothesis, the MINI showed that, compared with controls, survivors experienced a higher prevalence of anxiety and mood disorders even after a very long time since the diagnosis. These findings show that a substantial subset of survivors experiment a high prevalence of PD, higher than the general population, and should be screened for PD whatever the time since the diagnosis.