Second primary cancers after adjuvant radiotherapy in early breast cancer patients: a national population based study under the Danish Breast Cancer Cooperative Group (DBCG)

Association between radiotherapy and the risk of second primary malignancies in breast cancer patients with different estrogen receptor statuses

BACKGROUND

Breast cancer is the most common cancer among women. Second primary malignancies (SPMs) related to radiotherapy are significant complications. This study aims to investigate the correlation between radiotherapy and the occurrence of SPMs in breast cancer patients with different estrogen receptor statuses.

METHODS

We used data from the Surveillance, Epidemiology, and End Results (SEER) database, selecting estrogen receptor(+) and estrogen receptor(-) breast cancer patients from 1990 to 2015, with SPMs as the outcome measure. Fine-Gray competing risks regression and Poisson regression were employed to analyze the relationship between radiotherapy and the risk of SPMs in different estrogen receptor status groups.

RESULTS

Radiotherapy was associated with an increased risk of lung cancer, melanoma, non-Hodgkin lymphoma, and leukemia in estrogen receptor(+) patients. In estrogen receptor(-) patients, radiotherapy was linked to an increased risk of brain cancer and leukemia. The cumulative incidence, standardized incidence ratio, and subgroup analyses showed consistent results. In the dynamic assessment of radiotherapy-related risks, estrogen receptor(+) patients aged 50-70 exhibited a higher risk of leukemia and melanoma. Lung cancer risk was highest during a latency period of 20-30 years, while melanoma, non-Hodgkin lymphoma, and leukemia risks peaked within the first 10 years. For estrogen receptor(-) patients, brain cancer risk was higher between ages 50 and 70, and leukemia risk was elevated between ages 20 and 50.

CONCLUSION

Postoperative radiotherapy for breast cancer is associated with an increased risk of SPMs, with risks varying by estrogen receptor status and SPM type. Further research into the prevention of radiotherapy-related SPMs in different estrogen receptor status groups is crucial.

Validation of a breast cancer assay for radiotherapy omission: an individual participant data meta-analysis

BACKGROUND

There are currently no molecular tests to identify individual breast cancers where radiotherapy (RT) offers no benefit. Profile for the Omission of Local Adjuvant Radiotherapy (POLAR) is a 16-gene molecular signature developed to identify low-risk cancers where RT will not further reduce recurrence rates.

METHODS

An individual participant data meta-analysis was performed in 623 patients of node-negative estrogen receptor-positive and HER2-negative early breast cancer enrolled in 3 RT randomized trials for whom primary tumor material was available for analysis. A Cox proportional hazards model on time to locoregional recurrence was used to test the interaction between POLAR score and RT.

RESULTS

A total of 429 (69%) patients' tumors had a high POLAR score, and 194 (31%) had a low score. Patients with high POLAR score had, in the absence of RT, a 10-year cumulative incidence of locoregional recurrence (20%, 95% confidence interval [CI] = 15% to 26%, vs 5%, [CI] 2% to 11%) for those with a low score. Patients with a high POLAR score had a large benefit from RT (hazard ratio [HR] for RT vs no RT = 0.37, 95% CI = 0.23 to 0.60; P < .001). In contrast, there was no evidence of benefit from RT for patients with a low POLAR score (HR = 0.92, 95% CI = 0.42 to 2.02; P = .832). The test for interaction between RT and POLAR was statistically significant (P = .022).

CONCLUSIONS

POLAR is not only prognostic for locoregional recurrence but also predictive of benefit from RT in selected patients. Patients aged 50 years and older with estrogen receptor-positive and HER2-negative disease and a low POLAR score could consider omitting adjuvant RT. Further validation in contemporary clinical cohorts is required.

Evaluating Danish Breast Cancer Group locoregional radiotherapy guideline adherence in clinical treatment data 2008-2016: The DBCG RT Nation study

BACKGROUND AND PURPOSE

Guideline adherence in radiotherapy is crucial for maintaining treatment quality and consistency, particularly in non-trial patient settings where most treatments occur. The study aimed to assess the impact of guideline changes on treatment planning practices and compare manual registry data accuracy with treatment planning data.

MATERIALS AND METHODS

This study utilised the DBCG RT Nation cohort, a collection of breast cancer radiotherapy data in Denmark, to evaluate adherence to guidelines from 2008 to 2016. The cohort included 7448 high-risk breast cancer patients. National guideline changes included, fractionation, introduction of respiratory gating, irradiation of the internal mammary lymph nodes, use of the simultaneous integrated boost technique and inclusion of the Left Anterior Descending coronary artery in delineation practice. Methods for structure name mapping, laterality detection, detection of temporal changes in population mean lung volume, and dose evaluation were presented and applied. Manually registered treatment characteristic data was obtained from the Danish Breast Cancer Database for comparison.

RESULTS

The study found immediate and consistent adherence to guideline changes across Danish radiotherapy centres. Treatment practices before guideline implementation were documented and showed a variation among centres. Discrepancies between manual registry data and actual treatment planning data were as high as 10% for some measures.

CONCLUSION

National guideline changes could be detected in the routine treatment data, with a high degree of compliance and short implementation time. Data extracted from treatment planning data files provides a more accurate and detailed characterisation of treatments and guideline adherence than medical register data.

Proton therapy for breast cancer: Reducing toxicity

Radiotherapy is a crucial component in the holistic management of breast cancer, with approximately 60% of individuals diagnosed with breast cancer requiring this treatment. As the survival rate of individuals with breast cancer has significantly increased, there is a growing focus on the long-term well-being of patients. Proton therapy (PT) is a new and rapidly developing radiotherapy method. In comparison with conventional photon therapy, PT offers the benefits of decreased radiation toxicity and increased dosage in the designated region. This can extend patients' lifespan and enhance their overall well-being. The present analysis examines the function of PT in diminishing the harmful effects of radiation in cases of breast cancer, while also providing a brief overview of the future potential and obstacles associated with PT for breast cancer.

Comparative dosimetric study of h-IMRT and VMAT plans for breast cancer after breast-conserving surgery

AIM

To compare the dosimetric advantages and disadvantages between hybrid intensity-modulated radiation therapy (h-IMRT) and the volumetric modulated arc therapy (VMAT) technique in hypofractionated whole-breast irradiation (HF-WBI) for early-stage breast cancer (BC).

METHODS

The dose distribution of h-IMRT and VMAT plans was compared in 20 breast cancer patients. This comparison included evaluation of dosimetric parameters using dose volume histograms (DVHs) for the planning target volume (PTV) and organs-at-risk (OARs). Additionally, the study examined the normal tissue complication probability (NTCP), the second cancer complication probability (SCCP) and the tumor control probability (TCP) based on different models.

RESULTS

Significant differences were detected between the two plans, in terms of Machine units (MUs), the control points, 95 % volume (V95 %), dose homogeneity index (DHI) and conformity index (CI). The endpoint of grade II radiation pneumonitis and cardiac death due to ischemic heart disease were assessed. In h-IMRT plan, the NTCP values were marginally lower for radiation pneumonitis and slightly higher for cardiac death compared to VMAT plan, as determined by the Lyman-Kutcher-Burman model. The Schneider model was employed to predict the SCCP for both the bilateral lungs and contralateral breast, the results demonstrate that the h-IMRT plan outperforms the VMAT plan, with statistical significance. Additionally, the LQ-Poisson model was employed to forecast the TCP of the PTV, showing that the h-IMRT plan outperformed the VMAT plan (P > 0.05).

CONCLUSION

The h-IMRT technique, offering superior dose coverage and better therapeutic efficacy with fewer side effects as calculated by models, is more suitable for HF-WBI compared to the VMAT technique.

Prevalence and risk factors of thyroid nodules in breast cancer women with different clinicopathological characteristics: a cross-sectional study

BACKGROUND

Association between breast cancer (BC) and thyroid nodules (TNs) is still unclear. This research was to estimate the prevalence and risk factors of TN in Chinese BC women at initial diagnosis.

METHODS

1731 Chinese early-stage BC women at initial diagnosis underwent thyroid ultrasound and 1:1 age-matched Chinese healthy women underwent health examination in corresponding period were enrolled for analysis.

RESULTS

Prevalence of TN and TI-RADS ≥ 4 TN in BC patients (56.27% and 9.76%) were higher than healthy people (46.04% and 5.49%), respectively, P < 0.001. Among BC patients, prevalence of TN and TI-RADS ≥ 4 TN in hormone receptor (HR)-positive patients (59.57% and 11.81%) were higher than HR-negative patients (48.77% and 5.10%), respectively, P < 0.001, while without difference between HR-negative patients and healthy people. After adjusting for age and BMI, HR-positive patients had higher risk of TN (OR = 1.546, 95%CI 1.251-1.910, P < 0.001) and TI-RADS ≥ 4 TN (OR = 3.024, 95%CI 1.943-4.708, P < 0.001) than HR-negative patients. Furthermore, the risk of TI-RADS ≥ 4 TN was higher in patients with estrogen receptor (ER) positive (OR = 2.933, 95%CI 1.902-4.524), progesterone receptor (PR) positive (OR = 1.973, 95%CI 1.378-2.826), Ki-67 < 20% (OR = 1.797, 95%CI 1.280-2.522), and tumor size < 2 cm (OR = 1.804, 95%CI 1.276-2.552), respectively, P < 0.001.

CONCLUSIONS

Prevalence of TN, especially TI-RADS ≥ 4 TN, in Chinese early-stage BC women was higher than healthy people. HR-positive patients had higher prevalence and risk of TN, while without difference between HR-negative patients and healthy people. The increased risk of TN was correlated with ER-positive, PR-positive, lower Ki-67 expression, and smaller tumor size.

Increased risk of subsequent primary lung cancer among female hormone-related cancer patients: A meta-analysis based on over four million cases

BACKGROUND

The incidence rate of lung cancer in women has significantly increased over the past decade, and previous evidence has indicated a significant relationship between the elevated levels of sex hormones and the risk of lung cancer. Therefore, we hypothesized that female hormone-related cancer (FHRC) patients, including breast, endometrial, cervical, and ovarian cancer patients, may experience a higher risk of developing subsequent lung cancer. This meta-analysis aimed to identify the risk of lung cancer among FHRC patients compared to the general population.

METHODS

The PubMed, Web of Science, EMBASE, Cochrane Library, and CNKI databases were searched up to May 11, 2022. Standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) were used to identify the risk of subsequent lung cancer after FHRC. Subgroup analyses based on the follow-up time and tumor type were also conducted.

RESULTS

A total of 58 retrospective cohort studies involving 4,360,723 FHRC participants were included. The pooled results demonstrated that FHRC patients had a significantly increased risk of developing subsequent primary lung cancer (SIR = 1.61, 95% CI: 1.48-1.76, P <0.001). Subgroup analysis revealed an obvious trend of increasing lung cancer risk over time (SIRs for <5 years, ≥5 years, ≥10 years, ≥20 years, and ≥30 years after FHRC: 1.32, 1.59, 1.57, 1.68, and 1.95, respectively). In addition, subgroup analysis stratified by tumor type indicated an increased risk of developing subsequent lung cancer after breast (SIR = 1.25, P <0.001), endometrial (SIR = 1.40, P = 0.019), cervical (SIR = 2.56, P <0.001), and ovarian cancer (SIR = 1.50, P = 0.010).

CONCLUSION

FHRC patients are more likely to develop lung cancer than the general population. Furthermore, the increased risk of subsequent primary lung cancer is more obvious with a longer survival time and is observed in all types of hormone-related cancer.

REGISTRATION

International Platform of Registered Systematic Review and Meta-analysis Protocols: No. INPLASY202270044; https://inplasy.com/.

Second primary non-breast cancers in young breast cancer survivors

PURPOSE

We evaluated the incidence, timing, and risk factors for second primary non-breast cancers (SPNBC) among young breast cancer (BC) survivors.

METHODS

This study included participants of the Young Women's BC Study (YWS) who were diagnosed with stage 0-III BC between 2006 and 2016 and age 40 or younger at diagnosis (N = 1,230). Patient characteristics, treatment information, and clinical events were collected via serial surveys. Tumor and treatment data were obtained from medical record review. Five- and 10-year risks of SPNBCs were estimated via the cumulative incidence function, considering death, metastasis, or second primary BC as competing events. Fine and Gray subdistribution hazard models estimated subdistribution hazard ratios (sHRs) and 95% confidence intervals (CI) for SPNBC risk based on risk factors including demographics, germline genetics, primary BC characteristics, and treatments.

RESULTS

Among 1,230 women, over a median follow-up of 10.1 years, 47 patients (4%) developed an SPNBC. Types of malignancy included melanoma (n = 10), thyroid (n = 10), ovarian (n = 4), sarcoma (n = 4), uterine (n = 3), rectal (n = 3), bladder (n = 2), cervical (n = 2), head/neck (n = 2), lung (n = 2), lymphoma (n = 2), pancreatic (n = 2), and renal (n = 1). Five and 10-year cumulative incidence were 1.4% and 3.2%, respectively. Median time between primary BC and SPNBC was 7.3 years. No patient factors, primary tumor characteristics, or treatments were statistically significantly associated with SPNBC in univariable or multivariable models.

CONCLUSION

In this population, five-year cumulative incidence was higher than that reported among healthy women under 50 years of age, highlighting the importance of long-term surveillance for new non-breast cancers in young adult BC survivors.

Risk of thoracic soft tissue sarcoma after breast cancer radiotherapy: a population-based cohort study in Osaka, Japan

Postoperative radiotherapy for breast cancer reportedly increases the risk of thoracic soft tissue sarcomas, particularly angiosarcomas; however, the risk in the Japanese population remains unknown. Therefore, this study aimed to investigate the incidence of thoracic soft tissue sarcoma among patients with breast cancer in Japan and determine its association with radiotherapy. This retrospective cohort study used data from the population-based cancer registry of the Osaka Prefecture. The inclusion criteria were female sex, age 20-84 years, diagnosis of breast cancer between 1990 and 2010, no supraclavicular lymph node or distant metastasis, underwent surgery and survived for at least 1 year. The primary outcome was the occurrence of thoracic soft tissue sarcomas 1 year or later after breast cancer diagnosis. Among the 13 762 patients who received radiotherapy, 15 developed thoracic soft tissue sarcomas (nine angiosarcomas and six other sarcomas), with a median time of 7.7 years (interquartile range, 4.0-8.6 years) after breast cancer diagnosis. Among the 27 658 patients who did not receive radiotherapy, four developed thoracic soft tissue sarcomas (three angiosarcomas and one other sarcoma), with a median time of 11.6 years after diagnosis. The 10-year cumulative incidence was higher in the radiotherapy cohort than in the non-radiotherapy cohort (0.087 vs. 0.0036%, P < 0.001). Poisson regression analysis revealed that radiotherapy increased the risk of thoracic soft tissue sarcoma (relative risk, 6.8; 95% confidence interval, 2.4-24.4). Thus, although rare, breast cancer radiotherapy is associated with an increased risk of thoracic soft tissue sarcoma in the Japanese population.

Dosimetric evaluation of different planning strategies for hypofractionated whole-breast irradiation technique

Purpose.The dose hotspot areas in hypofractionated whole-breast irradiation (WBI) greatly increase the risk of acute skin toxicity because of the anatomical peculiarities of the breast. In this study, we presented several novel planning strategies that integrate multiple sub-planning target volumes (sub-PTVs), field secondary placement, and RapidPlan models for right-sided hypofractionated WBI.Methods.A total of 35 cases of WBI with a dose of 42.5 Gy for PTVs using tangential intensity-modulated radiotherapy (IMRT) were selected. Both PTVs were planned for simultaneous treatment using the original manual multiple sub-PTV plan (OMMP) and the original manual single-PTV plan (OMSP). The manual field secondary placement multiple sub-PTV plan (m-FSMP) with multiple objects on the original PTV and the manual field secondary placement single-objective plan (m-FSSP) were initially planned, which were distribution-based of V105 (volume receiving 105% of the prescription dose). In addition, two RapidPlan-based plans were developed, including the RapidPlan-based multiple sub-PTVs plan (r-FSMP) and the RapidPlan-based single-PTV plan (r-FSSP). Dosimetric parameters of the plans were compared, and V105 was evaluated using multivariate analysis to determine how it was related to the volume of PTV and the interval of lateral beam angles (ILBA).Results.The lowest mean V105 (5.64 ± 6.5%) of PTV was observed in m-FSMP compared to other manual plans. Upon validation, r-FSSP demonstrated superior dosimetric quality for OAR compared to the two other manual planning methods, except for V5(the volume of ipsilateral lung receiving 5 Gy) of the ipsilateral lung. While r-FSMP showed no significant difference (p = 0.06) compared to r-FSSP, it achieved the lowest V105 value (4.3 ± 4.5%), albeit with a slight increase in the dose to some OARs. Multivariate GEE linear regression showed that V105 is significantly correlated with target volume and ILBA.Conclusions.m-FSMP and r-FSMP can substantially enhance the homogeneity index (HI) and reduce V105, thereby minimizing the risk of acute skin toxicities, even though there may be a slight dose compromise for certain OARs.

Association of radiotherapy for stage I-III breast cancer survivors and second primary malignant cancers: a population-based study

PURPOSE

With life span extending, breast cancer survivors may face the possibility of developing second primary cancers (SPCs). The objective of this research is to investigate the risk factors, risk attribute to radiotherapy and the survivalship for SPCs.

METHODS

A total of 445 523 breast cancer patients were enrolled from Surveillance, Epidemiology, and End Results database in 2000-2018. The risk factors for SPCs development were confirmed by competing risk model, and then were integrated to the nomogram establishment. The cumulative incidence of SPCs including SBC (second breast cancer), SGC (second gynecological cancer), and SLC (second lung cancer) were estimated. The radiotherapy-associated risk for SPCs were evaluated by Poisson regression in radiotherapy and no-radiotherapy. Propensity score matching was used to reduce possible bias for survival comparison.

RESULTS

There were 57.63% patients in radiotherapy. The risk factors for developing SPCs were age, year, race, tumor size, stage, radiotherapy, grade, surgery, and histology. The cumulative incidence of SPCs was 7.75% in no-radiotherapy and 10.33% in radiotherapy. SLC, SBC, and SGC also appeared the similar results. The increased risk of developing SPCs were associated with radiotherapy in majority subgroups. The dynamic radiotherapy-associated risk for SPCs by age slightly increased risk was observed. Regardless radiotherapy or no-radiotherapy, the 10-year overall survival for SBC (radiotherapy: 59.41%; no-radiotherapy: 55.53%) and SGC (radiotherapy: 48.61%; no-radiotherapy: 35.53%) were worse than that among matched patients with only primary cancers.

CONCLUSIONS

Breast cancer survivors remained a high radiotherapy-associated risk for developing SPCs. The prognosis in radiotherapy was better than in no-radiotherapy for some specific SPCs. Largely attention should be paid to these patients.

Evaluation of conventional IMRT and VMAT strategies for postmastectomy radiation therapy after immediate implant-based reconstruction using the new ESTRO-ACROP contouring guidelines

This study evaluated the usability of conventional templates based on the new contour guidelines of the European Society of Radiation and Oncology and Advisory Committee in Radiation Oncology Practice (ESTRO-ACROP) for treatment plans of postmastectomy radiotherapy after immediate implant-based reconstruction. Intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans generated with two different treatment planning systems (TPSs, Eclipse and Monaco) were examined. Six computed tomography scans of patients aged 35-54 years were retrospectively analysed who had undergone mastectomy and breast reconstruction using silicone implants after being diagnosed with left breast cancer. Six radiation oncologists participated in this study, and each of them contoured the target volume of one left breast using conventional contour (CTV-CONV) and new contour (CTV-ESTRO) methods. This study showed that compared with CTV-CONV, using CTV-ESTRO with objectives and cost functions similar to those of TPSs worsened the target volume coverage and increased the total number of monitor units. Considering the organs at risk, CTV-ESTRO tended to increase the mean dose delivered to the contralateral lung. It is concluded that the approach used for the new ESTRO-ACROP contour method cannot be applied in a manner similar to that for the conventional breast contour method, implying that the new ESTRO-ACROP contour method may require more time for improving plans for a given treatment.

Intraoperative Radiation Therapy as a Safe Alternative to Whole Breast Radiation for Treatment of Minimally Invasive Breast Cancers: A Retrospective Cohort Study

BACKGROUND

Intraoperative radiation therapy (IORT) in select populations is a viable alternative to whole breast radiation therapy (WBRT) in the treatment of biopsy-proven localized invasive and non-invasive breast cancer. We aim to assess recurrence and complication rates following IORT in lumpectomy patients at a community hospital in Baltimore City.

METHODS

An IRB-approved retrospective cohort study was conducted on consecutive cases of lumpectomy with IORT from 2013 through 2020 by a single surgeon. Patient demographics, tumor and operative characteristics, and complications were retrieved from electronic medical records. Primary outcomes were postoperative complications and local recurrence rates.

RESULTS

The final cohort included 117 patients with mean follow-up time of 2.60 + 1.78 years. Mean age was 69.84 + 8.77 years. Thirty-three (28.21%) of patients developed a seroma. Odds of seroma formation were mildly significant for skin spacing [OR: 1.18, 95% CI: (1.02-1.37)] and balloon fill volume [1.04 (1.00-1.08)], but not for age, BMI, diabetes, former or current smoking status, history of WBRT, tumor size, or balloon size. Three (2.6%) patients had local recurrence. Odds of local recurrence were mildly significant for increased tumor size [1.14 (1.04-1.24)] and not significant for any other covariates.

CONCLUSIONS

IORT exposure did not confer higher rates of complications and the local recurrence rate mirrored that of the general population undergoing lumpectomy and WBRT. This study demonstrates the need for equitable treatment options based on individual needs: IORT is a safe alternative to WBRT in certain subpopulations, especially those with physical, social, or personal limitations preventing participation in a 3- to 7-week time commitment of WBRT.

Proton Therapy in Breast Cancer: A Review of Potential Approaches for Patient Selection

Proton radiotherapy may be a compelling technical option for the treatment of breast cancer due to its unique physical property known as the "Bragg peak." This feature offers distinct advantages, promising superior dose conformity within the tumor area and reduced radiation exposure to surrounding healthy tissues, enhancing the potential for better treatment outcomes. However, proton therapy is accompanied by inherent challenges, primarily higher costs and limited accessibility when compared to well-developed photon irradiation. Thus, in clinical practice, it is important for radiation oncologists to carefully select patients before recommendation of proton therapy to ensure the transformation of dosimetric benefits into tangible clinical benefits. Yet, the optimal indications for proton therapy in breast cancer patients remain uncertain. While there is no widely recognized methodology for patient selection, numerous attempts have been made in this direction. In this review, we intended to present an inspiring summarization and discussion about the current practices and exploration on the approaches of this treatment decision-making process in terms of treatment-related side-effects, tumor control, and cost-efficiency, including the normal tissue complication probability (NTCP) model, the tumor control probability (TCP) model, genomic biomarkers, cost-effectiveness analyses (CEAs), and so on. Additionally, we conducted an evaluation of the eligibility criteria in ongoing randomized controlled trials and analyzed their reference value in patient selection. We evaluated the pros and cons of various potential patient selection approaches and proposed possible directions for further optimization and exploration. In summary, while proton therapy holds significant promise in breast cancer treatment, its integration into clinical practice calls for a thoughtful, evidence-driven strategy. By continuously refining the patient selection criteria, we can harness the full potential of proton radiotherapy while ensuring maximum benefit for breast cancer patients.

Risk factors for developing both primary breast and primary ovarian cancer: A systematic review

OBJECTIVE

Women with breast cancer have an increased risk of primary ovarian cancer (BR→OV), and women with ovarian cancer have an increased risk of primary breast cancer (OV→BR). This systematic review summarizes risk factors for developing BR→OV and OV→BR.

METHODS

We searched PubMed and Embase until June 2022.

RESULTS

We identified 23 articles meeting our inclusion criteria. Studies observed a lower risk of BR→OV for Black versus White women, alcohol consumption, radiotherapy and hormone therapy, BRCA2 versus BRCA1, and ER/PR positive versus negative breast tumors, and a higher risk with family history of breast/ovarian cancer, triple negative versus luminal breast cancer, and higher grade breast tumors. There was an increased risk of OV→BR with family history of cancer.

CONCLUSIONS

Tumor characteristics, and genetic and familial factors are associated with risk of BR→OV and OV→BR. These results could aid clinicians in decision-making for breast and ovarian cancer patients, including risk-reducing strategies.

Second breast cancer: recurrence score results, clinicopathologic characteristics, adjuvant treatments, and outcomes-exploratory analysis of the Clalit registry

Data on using the 21-gene Recurrence Score (RS) testing on second breast cancer (BC; second primary or local recurrence) are lacking. This cohort study examined patients with first and second BC, who underwent 21-gene testing both times. It included a 'study-cohort' (60 N0/N1mi/N1 ER + HER2‒ BC patients with ≥2 RS results >1 year apart) and a 'general 21-gene-tested BC-cohort' (2044 previously described N0/N1mi/N1 patients). The median time between the first and second BC was 5.2 (IQR, 3.1-7.1) years; the second BC was ipsilateral in 68%. Patient/tumor characteristics of the first- and second-BC in the 'study-cohort' were similar, except for the RS which was higher in the second BC (median [IQR]: 23 [17-30] vs 17 [14-22], p < 0.001). Overall, 56 patients had follow-up data, of whom 5 experienced distant recurrence (2 RS 11-25 patients and 3 RS 26-100 patients). Studies exploring the prognostic utility of the RS in this setting are warranted.

Characteristics of Patients With Second Primary Lung Cancer Following Breast Cancer: A Retrospective Descriptive Study

BACKGROUND

Breast cancer (BC) is the most common noncutaneous malignancy in women and survivors are at an increased risk for secondary malignancy with lung cancer (LC) being the most common. There are few studies that have explored the clinicopathological specifics of LC in BC survivors.

METHODS

In this single-institution, retrospective study, we identified BC survivors who subsequently developed LC, examined their breast and LC clinical and pathological characteristics and compared them to the general BC and LC population as published in the literature.

RESULTS

In our study, we found the following associations that could be meaningful: an association between receiving radiation (RT) and LC (including a statistically significant P = .03 chance of ipsilateral LC after BC treatment with RT), a higher incidence and amount of smoking and LC, high BRCA positivity (78.9%) in the few patients who had germline testing, and a higher incidence of EGFR mutations in NSCLC after BC (60.9%) as well as an earlier stage of NSCLC disease.

CONCLUSION

Treatments such as RT, genetic factors such as BRCA mutations, and tobacco use may increase the risk of developing LC amongst BC survivors. Exploring this further can potentially lead to better risk stratification through modified low-dose CT chest screening protocols to catch LCs earlier and ultimately improve outcomes. Past studies have shown that BC survivors who are subsequently diagnosed with NSCLC may have improved OS compared with primary NSCLC and our study showed a high incidence of EGFR mutated NSCLC, which also suggest both improved prognosis and a different molecular profile of NSCLC, which warrants further investigation. Lastly, BC survivors who subsequently are diagnosed with NSCLC had earlier stage disease in our study, perhaps a result of surveillance, highlighting the importance of close monitoring of BC survivors.

Risk evaluation of secondary malignancies after radiotherapy of breast cancer in light of the continuous development of planning techniques

Secondary cancer risk is a significant concern for women treated with breast radiation therapy due to improved long-term survival rates. We evaluated the potential of new advanced automated planning algorithms together with hybrid techniques to minimize the excess absolute risk (EAR) for secondary cancer in various organs after radiation treatment for early staged breast cancer. Using CT data set of 25 patients, we generated 4 different radiation treatment plans of different complexity, including 3-dimensional conformal radiotherapy (3D-CRT), field-in-field (FinF), hybrid-IMRT (HMRT) and automated hybrid-VMAT (HVMAT) techniques. The organ-equivalent dose (OED) was calculated from differential dose-volume histograms on the basis of the "linear-exponential," "plateau," and "full mechanistic" dose-response models and was used to evaluate the EAR for secondary cancer in the contralateral breast (CB), contralateral lung (CL), and ipsilateral lung (IL). Statistical comparisons of data were performed by a Kruskal-Wallis analysis of variance. The planning objectives were fulfilled with all the planning techniques for both target coverage and organs-at-risk sparing. The differences in EAR for CB, CL and IL secondary tumor induction were not significant among the 4 techniques. For the CB and CL, the mean absolute difference did not reach 1 case of 10000 patient-years. For the IL, the mean absolute difference was up to 5 cases of 10,000 patient-years. In conclusion, the automated HVMAT technique allows an EAR reduction at the level of well-consolidated tangential 3D-CRT or FinF techniques, keeping all the HVMAT dosimetric improvements unchanged. On the basis of this analysis, the adoption of the HVMAT technique poses no increase in EAR and could be considered safe also for younger patients.

Occurrence of non-central nervous system cancers during postoperative follow-up of patients who underwent surgery for a WHO grade II glioma: implications for therapeutic management

PURPOSE

Survival is currently prolonged in WHO grade II glioma (GIIG). Although exceptionally described, long-term survivors may develop second primary cancers outside the central nervous system (CNS). Here, a consecutive series explored the association between non-CNS cancers (nCNSc) and GIIG in patients who underwent glioma resection.

METHODS

Inclusion criteria were adult patients operated for a GIIG who experienced nCNSc following cerebral surgery.

RESULTS

Nineteen patients developed nCNSc after GIIG removal (median time 7.3 years, range 0.6-17.3 years), including breast cancers (n = 6), hematological cancers (n = 2), liposarcomas (n = 2), lung cancers (n = 2), kidney cancers (n = 2), cardia cancers (n = 2), bladder cancer (n = 1), prostate cancer (n = 1) and melanoma (n = 1). The mean extent of GIIG resection was 91.68 ± 6.39%, with no permanent neurological deficit. Fifteen oligodendrogliomas and 4 IDH-mutated astrocytomas were diagnosed. Adjuvant treatment was administrated in 12 patients before nCNSc onset. Moreover, 5 patients underwent reoperation. The median follow-up from initial GIIG surgery was 9.4 years (range 2.3-19.9 years). Nine patients (47%) died in this period. The 7 patients who deceased from the second tumor were significantly older at nCNSc diagnosis than the 2 patients who died from the glioma (p = 0.022), with a longer time between GIIG surgery and the occurrence of nCNSc (p = 0.046).

CONCLUSION

This is the first study investigating the combination between GIIG and nCNSc. Because GIIG patients are living longer, the risk to experience second neoplasm and to die from it is increasing, especially in older patients. Such data may be helpful for tailoring the therapeutic strategy in neurooncological patients developing several cancers.

Risk and prognosis of secondary esophagus cancer after radiotherapy for breast cancer

Although radiation therapy (RT) improves locoregional recurrence and overall survival in breast cancer (BC), it is not yet clear whether RT affects the risk of patients with BC developing second esophageal cancer (SEC). We enrolled patients with BC as their first primary cancer from nine registries in the Surveillance, Epidemiology, and End Results (SEER) database between 1975 and 2018. Fine-Gray competing risk regressions were assessed to determine the cumulative incidence of SECs. The standardized incidence ratio (SIR) was used to compare the prevalence of SECs among BC survivors to that in the general population of the US. Kaplan-Meier survival analysis was applied to calculate the 10-year overall survival (OS) and cancer-specific survival (CSS) rates for SEC patients. Among the 523,502 BC patients considered herein, 255,135 were treated with surgery and RT, while 268,367 had surgery without radiotherapy. In a competing risk regression analysis, receiving RT was associated with a higher risk of developing an SEC in BC patients than that in the patients not receiving RT (P = .003). Compared to the general population of the US, the BC patients receiving RT showed a greater incidence of SEC (SIR, 1.52; 95% confidence interval [CI], 1.34-1.71, P < .05). The 10-year OS and CSS rates of SEC patients after RT were comparable to those of the SEC patients after no RT. Radiotherapy was related to an increased risk of developing SECs in patients with BC. Survival outcomes for patients who developed SEC after RT were similar to those after no RT.

Breast-Conserving Surgery with or without Irradiation in Early Breast Cancer

BACKGROUND

Limited level 1 evidence is available on the omission of radiotherapy after breast-conserving surgery in older women with hormone receptor-positive early breast cancer receiving adjuvant endocrine therapy.

METHODS

We performed a phase 3 randomized trial of the omission of irradiation; the trial population included women 65 years of age or older who had hormone receptor-positive, node-negative, T1 or T2 primary breast cancer (with tumors ≤3 cm in the largest dimension) treated with breast-conserving surgery with clear excision margins and adjuvant endocrine therapy. Patients were randomly assigned to receive whole-breast irradiation (40 to 50 Gy) or no irradiation. The primary end point was local breast cancer recurrence. Regional recurrence, breast cancer-specific survival, distant recurrence as the first event, and overall survival were also assessed.

RESULTS

A total of 1326 women were enrolled; 658 were randomly assigned to receive whole-breast irradiation and 668 to receive no irradiation. The median follow-up was 9.1 years. The cumulative incidence of local breast cancer recurrence within 10 years was 9.5% (95% confidence interval [CI], 6.8 to 12.3) in the no-radiotherapy group and 0.9% (95% CI, 0.1 to 1.7) in the radiotherapy group (hazard ratio, 10.4; 95% CI, 4.1 to 26.1; P<0.001). Although local recurrence was more common in the group that did not receive radiotherapy, the 10-year incidence of distant recurrence as the first event was not higher in the no-radiotherapy group than in the radiotherapy group, at 1.6% (95% CI, 0.4 to 2.8) and 3.0% (95% CI, 1.4 to 4.5), respectively. Overall survival at 10 years was almost identical in the two groups, at 80.8% (95% CI, 77.2 to 84.3) with no radiotherapy and 80.7% (95% CI, 76.9 to 84.3) with radiotherapy. The incidence of regional recurrence and breast cancer-specific survival also did not differ substantially between the two groups.

CONCLUSIONS

Omission of radiotherapy was associated with an increased incidence of local recurrence but had no detrimental effect on distant recurrence as the first event or overall survival among women 65 years of age or older with low-risk, hormone receptor-positive early breast cancer. (Funded by the Chief Scientist Office of the Scottish Government and the Breast Cancer Institute, Western General Hospital, Edinburgh; ISRCTN number, ISRCTN95889329.).

Targeting miR-5088-5p attenuates radioresistance by suppressing Slug

Radiotherapy is widely used for cancer treatment, but paradoxically, it has been reported that surviving cancer cells can acquire resistance, leading to recurrence or metastasis. Efforts to reduce radioresistance are required to increase the effectiveness of radiotherapy. miRNAs are advantageous as therapeutic agents because it can simultaneously inhibit the expression of several target mRNAs. Therefore, this study discovered miRNA that regulated radioresistance and elucidated its signaling mechanism. Our previous study confirmed that miR-5088-5p was associated with malignancy and metastasis in breast cancer. As a study to clarify the relationship between radiation and miR-5088-5p identified as onco-miRNA, it was confirmed that radiation induced hypomethylation of the promoter of miR-5088-5p and its expression increased. On the other hand, miR-5088-5p inhibitors were confirmed to reduce radiation-induced epithelial-mesenchymal transition, stemness, and metastasis by reducing Slug. Therefore, this study showed the potential of miR-5088-5p inhibitors as therapeutic agents to suppress radioresistance.

The use of Hybrid Techniques in Whole-Breast Radiotherapy: A Systematic Review

Objectives The development of new techniques in radiotherapy (RT) provides a better planned target volume (PTV) dose distribution while further improving the protection of organs at risk (OARs). The study aims to present the dosimetric results of studies using hybrid techniques in whole-breast radiotherapy (WBRT). Methods: This systematic literature review was conducted by scanning the relevant literature in PubMed, Scopus, and Web of Science following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Among the parameters are dose values for PTV and OARs beam contribute ratios, the value of monitors, and treatment times for different RT techniques. Initially, 586 articles were identified; 196 duplicate articles were removed leaving 391 articles for screening. Three-hundred and thirty-seven irrelevant articles were excluded, leaving 54 studies assessed for eligibility. A total of 22 articles met the search criteria to evaluate dosimetric results of hybrid and other RT techniques in WBRT. Results: According to the dosimetric data of the studies, hybrid intensity-modulated RT (H-IMRT) and hybrid volumetric-modulated arc therapy (H-VMAT) techniques give dosimetrically advantageous results in WBRT compared to other RT techniques. Conclusion: Hybrid techniques using appropriate beams contribute value and show great promise in improving dosimetric results in WBRT. However, there is a need for new studies showing the long-term clinical results of hybrid RT.

Links between Breast and Thyroid Cancer: Hormones, Genetic Susceptibility and Medical Interventions

Breast and thyroid glands are two common sites of female malignancies. Since the late 19th century, physicians have found that the cancers in either thyroid or mammary gland might increase the risk of second primary cancers in the other site. From then on, many observational clinical studies have confirmed the hypothesis and more than one theory has been developed to explain the phenomenon. Since the two glands both have secretory functions and are regulated by the hypothalamic-pituitary axis, they may share some common oncogenic molecular pathways. However, other risks factors, including medical interventions and hormones, are also observed to play a role. This article aims to provide a comprehensive review of the associations between the two cancers. The putative mechanisms, such as hormone alteration, autoimmune attack, genetic predisposition and other life-related factors are reviewed and discussed. Medical interventions, such as chemotherapy and radiotherapy, can also increase the risk of second primary cancers. This review will provide novel insights into the research designs, clinical managements and treatments of thyroid and breast cancer patients.

De-Escalating the Management of In Situ and Invasive Breast Cancer

Simple Summary

De-escalation of breast cancer treatment reduces morbidity and toxicity for patients. De-escalation is safe if cancer outcomes, such as recurrence and survival, remain unaffected compared to more radical regimens. This review provides an overview on treatment de-escalation for ductal carcinoma in situ (DCIS), local treatment of breast cancer, and surgery after neoadjuvant systemic therapy. Improvements in understanding the natural history and biology of breast cancer, imaging modalities, and adjuvant treatments have facilitated de-escalation of treatment over time.

Abstract

It is necessary to identify appropriate areas of de-escalation in breast cancer treatment to minimize morbidity and maximize patients’ quality of life. Less radical treatment modalities, or even no treatment, have been reconsidered if they offer the same oncologic outcomes as standard therapies. Identifying which patients benefit from de-escalation requires particular care, as standard therapies will continue to offer adequate cancer outcomes. We provide an overview of the literature on the de-escalation of treatment of ductal carcinoma in situ (DCIS), local treatment of breast cancer, and surgery after neoadjuvant systemic therapy. De-escalation of breast cancer treatment is a key area of investigation that will continue to remain a priority. Improvements in understanding the natural history and biology of breast cancer, imaging modalities, and adjuvant treatments will expand this even further. Future efforts will continue to challenge us to consider the true role of various treatment modalities.

Dose Estimation Using Optically Stimulated Luminescence Dosimeter and EBT3 Films for Various Treatment Techniques in Alderson Rando Phantom and Estimation of Secondary Cancer Incidence for Carcinoma of Left Breast

Aim

The aim of this study was to measure the dose to planning target and organ at risk (OAR) using Alderson Rando phantom for various treatment techniques in left breast radiotherapy and to estimate the secondary cancer incidence.

Materials and Methods

Eleven different combinations of plans containing four techniques (three dimensional conformal radiotherapy, intensity-modulated radiation therapy [IMRT], volumetric modulated arc therapy [VMAT], and combination of 3DCRT and VMAT plans (HYBRID)) were created with 6 MV FF and 6 MV FFF (flattening filter and flattening filter-free) photon energies in phantom. Planned target volume and OAR doses in 23 different locations were measured using optically stimulated luminescence dosimeter (OSLD) and EBT3 films. Assuming the age of exposure as 30 years, lifetime attributable risk (LAR) was estimated based on excess absolute risk (EAR) models outlined in the Biological Effects of Ionizing Radiation VII report.

Results

Film showed maximum deviations of 6.15% with IMRT_C_FF plan when compared with treatment planning system (TPS). The maximum percentage difference of 1.7% was found with OSLD measurement when compared with TPS for VMAT_T_FFF plan. EAR estimation was done for all the OARs including target. The LARs for left lung, right lung, and right breast were evaluated. The maximum LAR values of 2.92 ± 0.14 were found for left lung with VMAT_C_FFF plans.

Conclusion

This study shows that both OSLD and EBT3 films are suitable for dose measurements using Rando phantom. OSLD shows superior results when compared with films, especially with relatively larger distances. Maximum LAR values were found with VMAT_C_FFF plans. Considering the secondary cancer risk associated with the patients treated in the younger age group, it is suggested that in vivo dose estimation should be a part of treatment quality audit whenever possible.

Radiotherapy of Breast Cancer in Laterally Tilted Prone vs. Supine Position: What about the Internal Mammary Chain?

Background: In the multimodal breast-conserving curative therapy of some high-risk breast cancer patients, extended external beam radiotherapy (EBRT) not only to the breast but also to the supraclavicular fossa and the internal mammary chain (parasternal region (PSR)) is indicated. We report a dosimetric study on the EBRT of the breast (“B”) and the breast including PSR (“B + PSR”), comparing the supine and the laterally tilted prone patient positions in free breathing. Methods: The planning CT scans of 20 left- and 20 right-sided patients were analyzed. EBRT plans were calculated with 3D conformal EBRT (3D) and with intensity-modulated EBRT (IMRT) for “B” and “B + PSR” in the prone and supine positions. The mean and threshold doses were computed. The quality of EBRT plans was compared with an overall plan assessment factor (OPAF), comprising three subfactors, homogeneity, conformity, and radiogenic exposure of OAR. Results: In the EBRT of “B”, prone positioning significantly reduced the exposure of the OARs “heart” and “ipsilateral lung” and “lymphatic regions”. The OPAF was significantly better in the prone position, regardless of the planning technique or the treated breast side. In the EBRT of “B + PSR”, supine positioning significantly reduced the OAR “heart” exposure but increased the dose to the OARs “ipsilateral lung” and “lymphatic regions”. There were no significant differences for the OPAF, independent of the irradiated breast side. Only the IMRT planning technique increased the chance of a comparatively good EBRT plan. Conclusion: Free breathing prone positioning significantly improves plan quality in the EBRT of the breast but not in the EBRT of the breast + PSR.

Tumor-infiltrating lymphocytes predict improved overall survival after post-mastectomy radiotherapy: a study of the randomized DBCG82bc cohort

BACKGROUND

The predictive value of tumor-infiltrating lymphocytes (TILs) on the benefit from radiotherapy (RT) remains unclear. Our aim was to investigate the association between TILs and post-mastectomy RT (PMRT) regarding the risk of recurrence and survival in a randomized cohort.

MATERIAL AND METHODS

Stromal TILs were histologically estimated in 1011 tumors from high-risk breast cancer (BC) patients from the DBCG82bc trial. Patients were diagnosed between 1982 and 90, treated with total mastectomy and partial axillary lymph node dissection, randomized to ± PMRT followed by adjuvant systemic treatment. A competing risk model, Kaplan-Meier analysis and multivariate Cox regression analysis were used for correlating TILs and clinical outcome.

RESULTS

106 of 1011 patients (10.5%) showed high TILs using a 30% cut-off. In multivariate regression analysis, a high level of TILs was an independent factor associated with lower risk of distant metastasis (DM) and improved overall survival (OS), but without association with loco-regional control. High TILs were associated with a significantly greater OS after PMRT at 20 years compared to low TILs (8% improvement for low TILs (23% to 31%) vs. 22% for high TILs (26% to 48%), interaction-test: p = 0.028). The association between TILs and PMRT was more pronounced among estrogen-receptor negative (ER-) tumors, and patients having ER-/low TILs tumors showed no OS benefit from PMRT at 20 years (-4% improvement for low TILs (28% to 24%) vs. 23% for high TILs (20% to 43%). A similar trend in the association between high TILs and reduced risk of DM after PMRT was seen.

CONCLUSION

High TILs predict improved OS from PMRT in BC patients, and the association appeared especially strong for ER- tumors. A trend in the association between high TILs and reduced risk of DM after PMRT was seen. These findings may indicate that RT triggers an immune response inducing a systemic effect outside the treatment field.

Risk of primary lung cancer after breast cancer radiotherapy: a systematic review and meta-analysis

BACKGROUND

Epidemiological studies have shown that the risk of secondary malignancies may increase by radiotherapy. Lung cancer is the most important long-term complication of breast cancer radiotherapy.

METHODS

Major electronic databases including Scopus, Web of Science, and MEDLINE were searched. All cohort studies that investigated the association between radiotherapy for breast cancer and risk of primary lung, bronchus, and trachea cancers conducted until March 2021 were included. The study participants were evaluated regardless of their age and ethnicity. The Newcastle-Ottawa Scale was used to assess the quality of the studies. The designated effects were risk ratio (RR). The random-effects model was used to estimate the average effects.

RESULTS

Fifteen studies including 1,640,247 women with primary breast cancer were identified of which 937,151 had not received radiotherapy and 703,096 subjects had received radiotherapy. In general, there was no significant association between breast cancer radiotherapy and lung cancer based on 10 studies (RR = 0.95, 95% CI 0.87-1.02, P = 0.15), There was no association between breast cancer radiotherapy and lung, bronchus, and trachea cancers either based on 5 studies (RR = 0.98, 95% CI 0.93-1.02, P = 0.32).

CONCLUSION

Radiotherapy for breast cancer is not associated with an excess risk of lung cancer. Due to the limited number of studies, lack of data regarding smoking status, and substantial variation in exposure of the lungs in breast cancer radiotherapy worldwide, further investigations based on randomized controlled trials are suggested to address the potential risk of lung cancer after breast cancer radiotherapy.

Investigating the effectiveness of adjuvant therapy for patients with hormone receptor-positive ductal carcinoma in situ

BACKGROUND

This study compared the recurrence risk of single versus dual adjuvant radiotherapy (RT) and hormonal therapy (HT) following breast-conserving surgery (BCS) in patients with hormone receptor-positive ductal carcinoma in situ (DCIS).

METHODS

This retrospective cohort study used the Taiwan Cancer Registry database linking to the Taiwan National Health Insurance data from 2011 to 2016. We compared the recurrence risk between BCS-based regimens in Cox regressions and presented as adjusted hazard ratio (HR) and 95% confidence interval (95%CI).

RESULTS

The 1,836 study cohort with a low-to-intermediate risk of recurrence was grouped into BCS alone (6.1%), BCS+RT (6.2%), BCS+HT (23.4%) and BCS+HT+RT (64.3%) according to the initial treatments. During the follow-up (median: 3.3 years), the highest 5-year recurrence-free survival rate was in BCS+RT (94.1%) group and followed by BCS+HT+RT (92.8%), BCS+HT (87.4%) and BCS alone (84.9%). Of the single adjuvant therapies, RT was more effective than HT. Both BCS+HT (HR: 1.52, 95%CI: 0.99-2.35) and BCS+RT (HR: 1.10, 95%CI: 0.50-2.41) did not significantly increase recurrence risk comparing against the BCS+HT+RT group.

CONCLUSION

Single adjuvant demonstrated a similar subsequent recurrence risk with dual adjuvant. This study supports the proposition to de-escalate adjuvant treatments in patients with low-to-intermediate risk of DCIS recurrence.

Flattening Filter-Free Volumetric-Modulated Arc Radiotherapy for Left-Sided Whole-Breast, Partial-Breast, and Postmastectomy Irradiations

Purpose:

Unflattened photon beams exhibit many benefits over traditional flattened beams for radiotherapy (RT), but comprehensive evaluations of dosimetric results and beam-on time using flattening filter-free (FFF) beams for all types of breast irradiations are still lacking. The purpose of this study was to investigate if FFF RT can maintain equal or better dose coverage than standard flattened-beam RT while reducing doses to organs at risk (OARs) and beam-on time for various types of breast cancer irradiations.

Methods and Materials:

FFF volumetric-modulated arc therapy (FFF-VMAT) and standard VMAT (STD-VMAT) treatment plans were created for 15 whole-breast irradiation (WBI) patients with 50 Gy/25 fractions, 13 partial-breast irradiation (PBI) patients with 38.5 Gy/10 fractions, and 9 postmastectomy irradiation (PMI) patients with 50 Gy/25 fractions. Planning target volume (PTV) coverage and dose to OARs were evaluated.

Results:

Both techniques produced clinically acceptable plans for all three types of irradiations. For WBI, FFF-VMAT plans exhibited similar PTV and OARs evaluation metrics as STD-VMAT. For PBI, FFF-VMAT plans showed significantly lower mean and maximum doses for ipsilateral and contralateral lungs, contralateral breast, and heart. For PMI, FFF-VMAT plans showed significantly lower mean dose and V₅ for contralateral breast but significantly higher D_mean, D_max, and V₂₀ for ipsilateral lung and significantly higher D_mean, V_22.5, and V₃₀ for heart. FFF-VMAT techniques significantly reduced beam-on time than STD-VMAT for all cases.

Conclusion:

This work has shown that FFF beams are most beneficial for small-field irradiation such as PBI, and breast cancer patients could potentially benefit from the shortened beam-on time.

Prevention of radiation-induced cancers

The issue of radiation-induced cancers must be taken into consideration during therapeutic irradiations. Risk factors for radiation-induced cancer include: the age of the patients, the volumes irradiated, the presence of risk cofactors and the exposure of critical organs. Those should be part of the therapeutic decision, in terms of indication, as well as choice of the radiotherapy technique (including repositioning systems). We present the update of the recommendations of the French society for radiation oncology on the modalities for preventing radiation-induced cancers.

Treatment plan comparison of proton vs photon radiotherapy for lower-grade gliomas

Background and purpose

Patients with lower-grade gliomas are long-term survivors after radiotherapy and may benefit from the reduced dose to normal tissue achievable with proton therapy. Here, we aimed to quantify differences in dose to the uninvolved brain and contralateral hippocampus and compare the risk of radiation-induced secondary cancer for photon and proton plans for lower-grade glioma patients.

Materials and methods

Twenty-three patients were included in this in-silico planning comparative study and had photon and proton plans calculated (50.4 Gy(RBE = 1.1), 28 Fx) applying similar dose constraints to the target and organs at risk. Automatically calculated photon plans were generated with a 3 mm margin from clinical target volume (CTV) to planning target volume. Manual proton plans were generated using robust optimisation on the CTV. Dose metrics of organs at risk were compared using population mean dose-volume histograms and Wilcoxon signed-rank test. Secondary cancer risk per 10,000 persons per year (PPY) was estimated using dose-volume data and a risk model for secondary cancer induction.

Results

CTV coverage (V95%>98%) was similar for the two treatment modalities. Mean dose (D_mean) to the uninvolved brain was significantly reduced from 21.5 Gy (median, IQR 17.1–24.4 Gy) with photons compared to 10.3 Gy(RBE) (8.1–13.9 Gy(RBE)) with protons. D_mean to the contralateral hippocampus was significantly reduced from 6.5 Gy (5.4–11.7 Gy) with photons to 1.5 Gy(RBE) (0.4–6.8 Gy(RBE)) with protons. The estimated secondary cancer risk was reduced from 6.7 PPY (median, range 3.3–10.4 PPY) with photons to 3.0 PPY (1.3–7.5 PPY) with protons.

Conclusion

A significant reduction in mean dose to uninvolved brain and contralateral hippocampus was found with proton planning. The estimated secondary cancer risk was reduced with proton therapy.

Target coverage and cardiopulmonary sparing with the updated ESTRO-ACROP contouring guidelines for postmastectomy radiation therapy after breast reconstruction: a treatment planning study using VMAT and proton PBS techniques

BACKGROUND

The European Society for Therapeutic Radiology and Oncology Advisory Committee in Radiation Oncology Practice (ESTRO-ACROP) recently released new contouring guidelines for postmastectomy radiation therapy (PMRT) after implant-based reconstruction (IBR). As compared to prior ESTRO guidelines, the new guidelines primarily redefined the chest wall (CW) target to exclude the breast prosthesis. In this study, we assessed the impact of these changes on treatment planning and dosimetric outcomes using volumetric-modulated arc therapy (VMAT) and proton pencil-beam scanning (PBS) therapy.

METHODS

We performed a treatment planning study of 10 women with left-sided breast cancer who underwent PMRT after IBR. All target structures were delineated first using standard (ESTRO) breast contouring guidelines and then separately using the new (ESTRO-ACROP) guidelines. Standard organs-at-risk (OARs) and cardiac substructures were contoured. Four sets of plans were generated: (1) VMAT using standard ESTRO contours, (2) VMAT using new ESTRO-ACROP contours, (3) PBS using standard contours, and (4) PBS using new contours.

RESULTS

VMAT plans using the new ESTRO-ACROP guidelines resulted in modest sparing of the left anterior descending coronary artery (LAD) (mean dose: 6.99 Gy standard ESTRO vs. 6.08 Gy new ESTRO-ACROP, p = 0.010) and ipsilateral lung (V₂₀: 21.66% vs 19.45%, p = 0.017), but similar exposure to the heart (mean dose: 4.6 Gy vs. 4.3 Gy, p = 0.513), with a trend toward higher contralateral lung (V₅: 31.0% vs 35.3%, p = 0.331) and CW doses (V₅: 31.9% vs 35.4%, p = 0.599). PBS plans using the new guidelines resulted in further sparing of the heart (mean dose: 1.05 Gy(RBE) vs. 0.54 Gy(RBE), p < 0.001), nearly all cardiac substructures (LAD mean dose: 2.01 Gy(RBE) vs. 0.66 Gy(RBE), p < 0.001), and ipsilateral lung (V₂₀: 16.22% vs 6.02%, p < 0.001).

CONCLUSIONS

PMRT after IBR using the new ESTRO-ACROP contouring guidelines with both VMAT and PBS therapy is associated with significant changes in exposure to several cardiopulmonary structures.

The Pattern of Second Primary Tumours in Postmenopausal Women with Prior Breast Cancer in Western Romania: A Retrospective, Single-Institution Study

With improved survival, more patients with prior breast cancer are at risk of having a second primary cancer diagnosed. The pattern and impact of second primary cancers following breast cancer is important for overall breast cancer therapeutic management. Our study is a first analysis of the trend of second primary tumours over time in terms of incidence, sites with significantly elevated risks and correlation with stage, molecular subtype and therapeutic strategies conducted in Eastern Europe in postmenopausal women with breast cancer. Patients and methods: Our study population included 28 patients with prior breast cancer (BC) and second primary tumours, which were diagnosed and treated in our Institution between 2004 and 2017. The criteria for selection were based on the completeness of the documentation of the first treatment for breast cancer, stage of disease, molecular subtype, the site of origin of the second tumours and the survival data. Results: An increased risk of second primary cancer was associated with the 51–60 years age group (53.6%), with the greater prevalence in patients living in urban environments (82.1%). The use of chemotherapy increased the risk of the occurrence of gynecological second malignancies (75%). Our study is a first analysis of the trend of second primary tumours over time in terms of identifying sites with significantly elevated risks and correlation with therapeutic strategies conducted in Eastern Europe in postmenopausal women with breast cancer. Conclusions: Our study is a first analysis of the trend of second primary tumours over time in terms of correlation with luminal subtype and stage at diagnosis of primary cancer sites with significantly elevated risks and correlation with therapeutic strategies in postmenopausal women with breast cancer conducted in Eastern Europe. The reported time from primary to second primary malignancy onset, with a significantly higher rate for postmenopausal breast cancer patients, was less than one year (50%). With the advances and wider availability of genetic testing (e.g., gene panels), patients diagnosed with multiple primaries should be increasingly investigated for an underlying cancer predisposition. Postmenopausal women with breast cancer may benefit from increased surveillance and advice to avoid second malignancies.

Risk of primary gastrointestinal cancers following incident non-metastatic breast cancer: a Danish population-based cohort study

Objective

We examined the risk of primary gastrointestinal cancers in women with breast cancer and compared this risk with that of the general population.

Design

Using population-based Danish registries, we conducted a cohort study of women with incident non-metastatic breast cancer (1990–2017). We computed cumulative cancer incidences and standardised incidence ratios (SIRs).

Results

Among 84 972 patients with breast cancer, we observed 2340 gastrointestinal cancers. After 20 years of follow-up, the cumulative incidence of gastrointestinal cancers was 4%, driven mainly by colon cancers. Only risk of stomach cancer was continually increased beyond 1 year following breast cancer. The SIR for colon cancer was neutral during 2–5 years of follow-up and approximately 1.2-fold increased thereafter. For cancer of the oesophagus, the SIR was increased only during 6–10 years. There was a weak association with pancreas cancer beyond 10 years. Between 1990–2006 and 2007–2017, the 1–10 years SIR estimate decreased and reached unity for upper gastrointestinal cancers (oesophagus, stomach, and small intestine). For lower gastrointestinal cancers (colon, rectum, and anal canal), the SIR estimate was increased only after 2007. No temporal effects were observed for the remaining gastrointestinal cancers. Treatment effects were negligible.

Conclusion

Breast cancer survivors were at increased risk of oesophagus and stomach cancer, but only before 2007. The risk of colon cancer was increased, but only after 2007.

Contralateral breast dose with electronic compensators and conventional tangential fields - A clinical dosimetric study

Dose to the contralateral breast (CLB) from radiotherapy treatment has the potential to induce secondary breast cancer. Electronic tissue compensation (eComp) for breast cancer patients is one of the alternative methods to conventional 3D-conformal radiotherapy that eliminates the use of wedges. Several studies have investigated dose to the CLB using tangential fields involving wedges, intensity-modulated radiation therapy and volumetric modulated arc radiation therapy and various other techniques via treatment planning system calculations, Monte Carlo methods and phantoms. However, there are limited data published in assessing the actual dose received by the CLB from treatment with eComp-based tangential fields. In this study, the CLB dose for patients undergoing tangential field radiotherapy with eComp and enhanced dynamic wedged (standard) tangential fields was measured and compared to assess the CLB dose between the two methods. Measurements were conducted on a randomised trial of 40 patients, 20 of them had undergone standard planning, and the remaining 20 were treated with eComp. The mean surface dose measured with TLDs at 3cm from the medial tangential border for eComp and standard techniques was 10.04±1.37% and 10.14±2.05%, respectively for a prescription dose of 2.65Gy/fraction. The estimated dose at 1cm depth in tissue, measured with the use of perspex domes placed over the TLD at the same location, was 5.12±0.87% and 6.29±2.01% for eComp and standard, respectively. The CLB dose is dependent on the proximity of the medial tangential field edge to the contralateral breast and is patient-specific. The results of this study show that at 1cm depth, eComp technique delivers significantly less dose (p<0.05) to the CLB as compared to standard tangential fields. Furthermore, the surface dose measured for both eComp and standard are comparable indicating that the eComp-based tangential field technique does not contribute any excess dose to CLB when compared to standard tangential fields. The excess relative risk (ERR) for radiation-induced cancers for eComp was found to be 0.08, compared to 0.11 for standard tangential fields.

Risk of primary lung cancer after adjuvant radiotherapy in breast cancer-a large population-based study

Adjuvant radiotherapy (RT) for breast cancer (BC) has been associated with an increased risk of later radiation-induced lung cancer (LC). We examined the risk of primary LC in a population-based cohort of 52300 women treated for BC during 1992 to 2012, and 253796 age-matched women without BC. Cumulative incidence of LC was calculated by the Kaplan-Meier method, and the risk of LC after BC treatment was estimated by Cox proportional hazards regression analyses. Women with BC receiving RT had a higher cumulative incidence of LC compared to women with BC not receiving RT and women without BC. This became apparent 5 years after RT and increased with longer follow-up. Women with BC receiving RT had a Hazard ratio of 1.59 (95% confidence interval 1.37-1.84) for LC compared to women without BC. RT techniques that lower the incidental lung doses, e.g breathing adaption techniques, may lower this risk.

Epidemiology and clinicopathological features of lung cancer in patients with prior history of breast cancer

Breast cancer is the most common malignancy in women, and lung cancer, the leading cause of cancer-related mortality in the United States, is the most common subsequent primary cancer among breast cancer survivors. In this review, we examine the risk factors that cause subsequent primary lung cancer after breast cancer (referred to herein as BCLC patients) as well as the prognostic factors that may affect survival. Notable clinicopathological features include patient characteristics such as age, smoking history, and the presence of EGFR or BRCA mutations, as well as factors related to the treatment of breast cancer such as radiation, surgery, chemotherapy, stage, anti-estrogen therapy, and ER/PR/HER2 status.

Metastases of Urothelium Carcinoma: Differential Diagnosis, Resection, and Survival

BACKGROUND

 Due to its very aggressive nature and low survival chances, the metastasized urothelium carcinoma poses a challenge in regard to therapy. The gold-standard chemotherapy is platinum based. The therapy options are considered controversial, including new systemic therapies. In this respect, surgical therapies, as already established for pulmonary metastases of other tumor entities play an increasingly important role. The consumption of nicotine is a risk factor not only for urothelium carcinoma but also for a pulmonary carcinoma. Thus, we examined the frequency of a second carcinoma in this cohort.

METHODS

 We retrospectively examined patients who had a differential diagnosis of pulmonary metastases, as well as those patients who underwent a surgery due to pulmonary metastases of a urothelium carcinoma between 1999 and 2015.

RESULTS

 A total of 139 patients came to our clinic with the differential diagnosis of pulmonary metastases of a urothelium carcinoma. The most common diagnosis was pulmonary carcinoma (53%). Thirty-one patients underwent surgeries due to pulmonary metastases of a urothelium carcinoma. The median survival was 53 months and the 5-year survival was 51%. With the univariate analysis, only the relapse-free interval of more than 10 months was statistically significant (p < 0.001).

CONCLUSION

 There is a high coincidence of urothelial carcinoma and lung carcinoma. A histological confirmation should be endeavored. Selected patients undergoing a pulmonary metastasis resection have a survival advantage during the multimodal treatment of pulmonary metastasized urothelial carcinomas. For a definitive recommendation, randomized trials including a uniform multimodal therapy regimen and higher numbers of patients are necessary.

Smoking, Radiation Therapy, and Contralateral Breast Cancer Risk in Young Women

Evidence is mounting that cigarette smoking contributes to second primary contralateral breast cancer (CBC) risk. Whether radiation therapy (RT) interacts with smoking to modify this risk is unknown. In this multicenter, individually-matched case-control study, we examined the association between RT, smoking, and CBC risk. The study included 1,521 CBC cases and 2,212 controls with unilateral breast cancer, all diagnosed with first invasive breast cancer between 1985-2008 at age <55 years. Absorbed radiation doses to contralateral breast regions were estimated with thermoluminescent dosimeters in tissue-equivalent anthropomorphic phantoms and smoking history was collected by interview. Rate ratios (RRs) and 95% confidence intervals (CIs) for CBC risk were estimated by multivariable conditional logistic regression. There was no interaction between any measure of smoking with RT to increase CBC risk (eg, the interaction of continuous RT dose with smoking at first breast cancer diagnosis [ever/never]: RR = 1.00, 95% CI = 0.89-1.14; continuous RT dose with years smoked: RR = 1.00, 95% CI = 0.99-1.01; and continuous RT dose with lifetime pack-years: RR = 1.00, 95% CI = 0.99-1.01). There was no evidence that RT further increased CBC risk in young women with first primary breast cancer who were current smokers or had smoking history.

The impact of variable relative biological effectiveness in proton therapy for left-sided breast cancer when estimating normal tissue complications in the heart and lung

The aim of this study was to evaluate the clinical impact of relative biological effectiveness (RBE) variations in proton beam scanning treatment (PBS) for left-sided breast cancer versus the assumption of a fixed RBE of 1.1, particularly in the context of comparisons with photon-based three-dimensional conformal radiotherapy (3DCRT) and volumetric modulated arc therapy (VMAT). Ten patients receiving radiation treatment to the whole breast/chest wall and regional lymph nodes were selected for each modality. For PBS, the dose distributions were re-calculated with both a fixed RBE and a variable RBE using an empirical RBE model. Dosimetric indices based on dose-volume histogram analysis were calculated for the entire heart wall, left anterior descending artery (LAD) and left lung. Furthermore, normal tissue toxicity probabilities for different endpoints were evaluated. The results show that applying a variable RBE significantly increases the RBE-weighted dose and consequently the calculated dosimetric indices increases for all organs compared to a fixed RBE. The mean dose to the heart and the maximum dose to the LAD and the left lung are significantly lower for PBS assuming a fixed RBE compared to 3DCRT. However, no statistically significant difference is seen when a variable RBE is applied. For a fixed RBE, lung toxicities are significantly lower compared to 3DCRT but when applying a variable RBE, no statistically significant differences are noted. A disadvantage is seen for VMAT over both PBS and 3DCRT. One-to-one plan comparison on 8 patients between PBS and 3DCRT shows similar results. We conclude that dosimetric analysis for all organs and toxicity estimation for the left lung might be underestimated when applying a fixed RBE for protons. Potential RBE variations should therefore be considered as uncertainty bands in outcome analysis.

Calculating and estimating second cancer risk from breast radiotherapy using Monte Carlo code with internal body scatter for each out-of-field organ

Out-of-field organs are not commonly designated as dose calculation targets during radiation therapy treatment planning, but they might entail risks of second cancer. Risk components include specific internal body scatter, which is a dominant source of out-of-field doses, and head leakage, which can be reduced by external shielding. Our simulation study quantifies out-of-field organ doses and estimates second cancer risks attributable to internal body scatter in whole-breast radiotherapy (WBRT) with or without additional regional nodal radiotherapy (RNRT), respectively, for right and left breast cancer using Monte Carlo code PHITS. Simulations were conducted using a complete whole-body female model. Second cancer risk was estimated using the calculated doses with a concept of excess absolute risk. Simulation results revealed marked differences between WBRT alone and WBRT plus RNRT in out-of-field organ doses. The ratios of mean doses between them were as large as 3.5-8.0 for the head and neck region and about 1.5-6.6 for the lower abdominal region. Potentially, most out-of-field organs had excess absolute risks of less than 1 per 10,000 persons-year. Our study surveyed the respective contributions of internal body scatter to out-of-field organ doses and second cancer risks in breast radiotherapy on this intact female model.

Effect of protective glasses on radiation dose to eye lenses during whole breast irradiation

OBJECTIVES

The efficacy of radiotherapy for breast cancer has greatly improved owing to better irradiation methods. Radiotherapy aims to deliver therapeutic doses to predetermined target volumes while sparing surrounding healthy tissues. However, there are few reports on radiation exposure to eye lenses, and the recommended exposure limits to ocular lens have been substantially reduced in recent years. This study aimed to investigate the amount of radiation exposure to eye lenses using optically stimulated luminescence dosimeters (OSLDs) and determine whether wearing special protective devices to protect the eyes, as an organ at risk, during whole breast irradiation, is necessary.

METHODS

This experiment used OSLDs on water-equivalent phantom to measure the change in scattered radiation dose due to the difference of irradiation field while using 4- and 6-MV photons of TrueBeam linear accelerator. Using a total treatment dose of 50 Gy, a target was positioned to approximate the breast, and a plan was formulated to deliver 2 Gy per treatment by tangential irradiation. The mean (SD) irradiation dose at the lens position outside the irradiation field was reported.

RESULTS

The scattered radiation dose outside the irradiation field was more affected by the irradiation field size than by the radiation energy. The out-of-field irradiation dose with a larger field of view was higher than that with a smaller field of view. The use of 0.07- and 0.83-mm-thick lead shield protective glasses reduced the radiation dose by 56.1% (P < .001) and 55.6% (P < .001), respectively.

CONCLUSIONS

In this experimental model, the amount of radiation the eye was exposed to during whole breast irradiation was determined by the distance of the eye from the radiation field edge and by wearing protective glasses. In clinical practice, the protection offered by eyeglasses may reduce the risk of long-term side effects and allow the use of higher intensive radiotherapy.

10-Year Breast Cancer Outcomes in Women ≤35 Years of Age

PURPOSE

Breast cancer diagnosis at a very young age has been independently correlated with worse outcomes. Appropriately intensifying treatment in these patients is warranted, even as we acknowledge the risks of potentially mutagenic adjuvant therapies. We examined local control, distant control, overall survival, and secondary malignancy rates by age cohort and by initial surgical strategy.

METHODS AND MATERIALS

Female patients less than or equal to 35 years of age diagnosed with invasive breast cancer from January 1, 1990, to December 31, 2010, were identified. Control groups of those aged 36 to 50 years (n = 6246) and 51 to 70 years (n = 7294) were delineated from an institutional registry. Clinicopathologic and follow-up information was collected. Chi-squared test was used to compare frequencies of categorical variables. Survival endpoints were evaluated using Kaplan-Meier methodology.

RESULTS

A total of 529 patients ≤35 years of age met criteria for analysis. The median age of diagnosis was 32 years (range 20-35). Median follow-up was 10.3 years. On multivariable analysis, factors associated with overall survival (OS) were tumor size (hazard ratio [HR] 1.14, P = .02), presence of lymphovascular invasion (HR 2.2, P <.001), estrogen receptor positivity (HR 0.64, P = .015), receipt of adjuvant chemotherapy (HR 0.52, P = .035), and black race (HR 2.87, P <.001). The ultra-young were more likely to experience local failure compared with the aged 36 to 50 group (HR 2.2, 95% CI 1.8-2.6, P < .001) and aged 51 to 70 group (HR 3.1, 95% CI 2.45 - 3.9, P <.001). The cumulative incidence of secondary malignancies at 5 and 10 years was 2.2% and 4.4%, respectively. Receipt of radiation was not significantly associated with secondary malignancies or contralateral breast cancer.

CONCLUSION

Survival and recurrence outcomes in breast cancer patients ≤35 years are worse compared with those aged 36 to 50 or 51 to 70 years. Based on our data, breast conservation therapy is appropriate for these patients, and the concern for second malignancies should not impinge on the known indications for postoperative radiation therapy.

Postmastectomy Radiation Therapy Planning After Immediate Implant-based Reconstruction Using the European Society for Radiotherapy and Oncology-Advisory Committee in Radiation Oncology Practice Consensus Guidelines for Target Volume Delineation

AIMS

To evaluate how common radiation therapy techniques perform in the setting of the new European Society for Radiotherapy and Oncology-Advisory Committee in Radiation Oncology Practice (ESTRO-ACROP) delineation recommendations for immediate breast reconstruction (IBR).

MATERIALS AND METHODS

Seven Danish radiation therapy centres and six international European centres participated in this project. Two breast cancer cases (one left-sided and one right-sided) with a retropectoral implant were chosen for radiation therapy planning using deep-inspiration breath-hold. Target volumes were delineated according to ESTRO-ACROP delineation recommendations. The centres were asked to plan the cases using any radiation therapy technique according to the Danish Breast Cancer Group plan objectives.

RESULTS

In total, 35 treatment plans were collected. Half of the submitted plans, for both the left-sided and the right-sided case, used the field-in-field (FiF) technique (nine for each), a quarter used volumetric arc radiation therapy (VMAT; five for right-sided, four for left-sided) and the remaining quarter was a mix of inverse intensity-modulated radiation therapy (IMRT), helicoidal therapy and hybrid (combined open fields and VMAT) techniques. Mean clinical target volume doses were in the range 99-102% of the prescribed dose. The median FiF mean heart dose (MHD) for right-sided radiation therapy was 1 Gy (range 0.8-3.7) and 5.2 Gy for left-sided radiation therapy (range 2.2-6.5). For right-sided radiation therapy, the median VMAT MHD was 3.42 Gy, for IMRT was 2.3 Gy and for helicoidal therapy was 5.1 Gy. For left-sided radiation therapy, the median VMAT MHD was 6.3 Gy, for IMRT was 7.8 Gy and for helicoidal therapy was 7.3 Gy.

CONCLUSIONS

Different radiation therapy techniques could be used to plan radiation therapy in the setting of IBR. FiF provided good coverage with acceptable organ at risk doses. The best dose distribution results as a trade-off between the objectives of target volume coverage and high-dose organ at risk inclusion. The radiation therapy technique affects the interplay between these objectives.