Risk of second malignancies after adjuvant radiotherapy for breast cancer: a large-scale, single-institution review

Radiation-induced sarcomas of the craniofacial region: A systematic review

BACKGROUND

Radiation-induced sarcomas (RIS) are rare entities that have been studied infrequently in large cohorts, with most data derived from case reports or small series. This study aims to systematically evaluate existing data to synthesize and consolidate current knowledge.

METHODS

An electronic literature search was conducted using PubMed and the Cochrane Library. The search included studies and case reports with clinico-histopathological and survival data on craniofacial RIS.

RESULTS

Among 1237 studies identified, 143 studies with 701 patients were included. The average patient age was 48 years, with men nearly twice as likely to develop RIS. RIS had an average latency period of 12 years, with an average radiation dose of 63 Gy. Radiation-induced osteosarcomas (42.1 %) were most common, followed by fibrosarcomas (21.1 %). Nasopharyngeal carcinoma (53.0 %) and retinoblastoma (10.3 %) were the most prevalent primary tumors. 5.4 % of patients received radiotherapy for benign disease. The average latency period in this group was approximately 1.5 times longer than that observed in the group with malignancies; however, the average radiation dose was also approximately 15 Gy lower. Local recurrences occurred after an average of 16 months. The 1-, 2-, and 5-year survival rates were 67.8 %, 47.1 %, and 25.0 %, respectively. Surgical therapy showed the best survival rates (33.3 % after 5 years) while isolated chemotherapy yielded the lowest (0.0 %).

CONCLUSION

The prognosis for craniofacial RIS remains poor despite aggressive treatment. Surgical intervention is the primary therapeutic approach, but optimal treatment regimens and the role of (neo-)adjuvant therapies require further investigation. This study underscores the complexity of managing RIS and highlights the need for ongoing research to improve outcomes.

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.

Machine learning identifies the association between second primary malignancies and postoperative radiotherapy in young-onset breast cancer patients

BACKGROUND

A second primary malignant tumor is one of the most important factors affecting the long-term survival of young women with breast cancer (YWBC). As one of the main treatments for breast cancer YWBC patients, postoperative radiotherapy (PORT) may increase the risk of second primary malignancy (SPM).

METHODS

Machine learning components, including ridge regression, XGBoost, k-nearest neighbor, light gradient boosting machine, logistic regression, support vector machine, neural network, and random forest, were used to construct a predictive model and identify the risk factors for SPMs with data from the Surveillance, Epidemiology and End Results. Multivariate logistic regression analysis was used to assess the risk of SPM associated with PORT. The cumulative incidence of SPMs was determined by competing risk regression analysis.

RESULTS

Among the 44223 YWBC patients included in our study, 3017 developed SPMs. Among all the clinical characteristics, PORT was the most common SPM. YWBC patients receiving PORT had significantly greater risks of second primary solid malignancies (SPSMs, RR = 1.61), including breast cancer (RR = 1.89), lung cancer (RR = 2.12) and thyroid cancer (RR = 1.48), but not second primary hematologic malignancies (RR = 1.32; 0.94-1.88). SPSMs were more common in YWBC individuals who were black, had a lower median household income and had fewer lymph nodes examined. Additionally, we developed a prediction nomogram with an area under the curve of 0.75 to assess the likelihood of developing SPMs.

CONCLUSION

YWBC patients receiving PORT had a greater risk of developing SPSMs (thyroid, lung, and breast cancer), indicating the necessity of long-term surveillance of these patients. Standard adjuvant PORT should not be recommended for breast cancer patients with favorable histology and a low risk of relapse.

Development of a Second Primary Lung Cancer Following a Primary Breast Cancer: A Case Series

Breast cancer (BC) accounts for 24.2% of all women's malignant tumors, with rising survival rates due to advancements in chemotherapy and targeted treatments. However, second primary cancers, particularly lung cancer (LC), have become more prevalent, often emerging approximately 10 years after BC treatment. This study presents a case series of 9 women diagnosed with second primary LC following BC, treated at a high-complexity hospital in Colombia between 2014 and 2019. All initial BCs were ductal carcinomas, 7 were triple negative, 1 was human epidermal growth factor receptor 2 positive, and 1 was estrogen and progesterone positive. Each patient had undergone radiation therapy, and 7 had received chemotherapy, increasing their LC risk. The second primary LCs, all adenocarcinomas, were confirmed using immunohistochemical stains for thyroid transcription factor-1 (TTF-1), Napsin A, and estrogen receptor (ER) status. The interval between treatments and LC detection ranged from 1 to 17 years, with 4 cases identified after 10 years and 3 within 1 to 3 years, underscoring the need for prolonged surveillance. Seven LCs were ipsilateral to the BC and radiation site, while 2 were contralateral, highlighting the necessity of monitoring both sides for potential LC development. This case series enhances the local epidemiological understanding, showing that prior radiotherapy for BC and histological analysis are key in characterizing second primary LC patients. The study emphasizes the critical role of accurate histological diagnosis in guiding treatment approaches for lung lesions in BC survivors.

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.

Landscape of germline pathogenic variants in patients with dual primary breast and lung cancer

BACKGROUND

Cancer predisposition is most often studied in the context of single cancers. However, inherited cancer predispositions can also give rise to multiple primary cancers. Yet, there is a paucity of studies on genetic predisposition in multiple primary cancers, especially those outside of well-defined cancer predisposition syndromes. This study aimed to identify germline variants associated with dual primary cancers of the breast and lung.

METHODS

Exome sequencing was performed on germline DNA from 55 Singapore patients (52 [95%] never-smokers) with dual primaries in the breast and lung, confirmed by histopathology. Using two large control cohorts: the local SG10K_Health (n = 9770) and gnomAD non-cancer East Asians (n = 9626); and two additional local case cohorts of early-onset or familial breast cancer (n = 290), and lung cancer (n = 209), variants were assessed for pathogenicity in accordance with ACMG/AMP guidelines. In particular, comparisons were made with known pathogenic or likely pathogenic variants in the ClinVar database, pathogenicity predictions were obtained from in silico prediction software, and case-control association analyses were performed.

RESULTS

Altogether, we identified 19 pathogenic or likely pathogenic variants from 16 genes, detected in 17 of 55 (31%) patients. Six of the 19 variants were identified using ClinVar, while 13 variants were classified pathogenic or likely pathogenic using ACMG/AMP guidelines. The 16 genes include well-known cancer predisposition genes such as BRCA2, TP53, and RAD51D; but also lesser known cancer genes EXT2, WWOX, GATA2, and GPC3. Most of these genes are involved in DNA damage repair, reaffirming the role of impaired DNA repair mechanisms in the development of multiple malignancies. These variants warrant further investigations in additional populations.

CONCLUSIONS

We have identified both known and novel variants significantly enriched in patients with primary breast and lung malignancies, expanding the body of known cancer predisposition variants for both breast and lung cancer. These variants are mostly from genes involved in DNA repair, affirming the role of impaired DNA repair in the predisposition and development of multiple cancers.

Special issue. De-escalation of loco-regional treatment in breast cancer: Time to find the balance? Partial breast irradiation

Breast cancer is the most common cancer in women worldwide. Over the past few decades, remarkable progress has been made in understanding the biology and pathology of breast cancer. A personalized conservative approach has been currently adopted addressing the patient's individual risk of relapse. After postoperative whole breast irradiation for early-stage breast cancer, a rate of recurrences outside the initial tumour bed lower than 4% was observed. Thus, the highest benefits of breast irradiation seem to result from the dose delivered to the tissue neighbouring the tumour bed. Nonetheless, reducing treatment morbidity while maintaining radiation therapy's ability to decrease local recurrences is an important challenge in treating patients with radiation therapy. In this regard, strategies such as partial-breast irradiation have been developed to reduce toxicity without compromising oncologic outcomes. According to the national and international published guidelines, clinical oncologists can refer to specific dose/fractionation schedules and eligible criteria. However, there are still some areas of open questions. Breast cancer represents a multidisciplinary paradigm; it should be considered a heterogeneous disease where a "one-treatment-fits-all" approach cannot be considered an appropriate option. This is a wide overview on the main partial breast irradiation advantages, risks, timings, techniques, and available recommendations. We aim to provide practical findings to support clinical decision-making, exploring future perspectives, towards a balance for optimisation of breast cancer.

Three-dimensional conformal radiotherapy (3D-CRT) vs. volumetric modulated arc therapy (VMAT) in deep inspiration breath-hold (DIBH) technique in left-sided breast cancer patients-comparative analysis of dose distribution and estimation of projected secondary cancer risk

PURPOSE

The purpose of this study was to compare two techniques of irradiation of left-sided breast cancer patients who underwent breast-conserving surgery, three-dimensional conformal radiotherapy technique (3D-CRT) and volumetric modulated arc therapy (VMAT), in terms of dose distribution in the planning target volume (PTV) and organs at risk (OARs). The second aim of the study was estimation of the projected risk of radiation-induced secondary cancer for both radiotherapy techniques.

MATERIALS AND METHODS

For 25 patients who underwent CT simulation in deep inspiration breath-hold (DIBH), three treatment plans were generated: one using a three-dimensional conformal radiotherapy technique and two using volumetric modulated arc therapy. First VMAT-DIBH geometry consisted of three partial arcs (ARC-DIBH 3A) and second consisted of four partial arcs (ARC-DIBH 4A). Cumulative dose-volume histograms (DVHs) were used to compare dose distributions within the PTV and OARs (heart, left anterior descending coronary artery [LAD], ipsilateral and contralateral lung [IL, CL], and contralateral breast [CB]). Normal tissue complication probabilities (NTCPs) and organ equivalent doses (OEDs) were calculated using the differential DVHs. Excess absolute risks (EARs) for second cancers were estimated using Schneider's full mechanistic dose-response model.

RESULTS

All plans fulfilled the criterium for PTV V95% ≥ 95%. The PTV coverage, homogeneity, and conformity indices were significantly better for VMAT-DIBH. VMAT showed a significantly increased mean dose and V5Gy for all OARs, but reduced LAD D_max by 15 Gy. For IL, CL, and CB, the 3D-CRT DIBH method achieved the lowest values of EAR: 28.38 per 10,000 PYs, 2.55 per 10,000 PYs, and 4.48 per 10,000 PYs (p < 0.001), compared to 40.29 per 10,000 PYs, 15.62 per 10,000 PYs, and 23.44 per 10,000 PYs for ARC-DIBH 3A plans and 41.12 per 10,000 PYs, 15.59 per 10,000 PYs, and 22.73 per 10,000 PYs for ARC-DIBH 4A plans. Both techniques provided negligibly low NTCPs for all OARs.

CONCLUSION

The study shows that VMAT-DIBH provides better OAR sparing against high doses. However, the large low-dose-bath (≤ 5 Gy) is still a concern due to the fact that a larger volume of normal tissues exposed to lower doses may increase a radiation-induced risk of secondary cancer.

Allogeneic hematopoietic cell transplantation in patients with a hematologic malignancy and a prior history of breast cancer

PURPOSE

To compare the outcome of allogeneic stem cell transplantation for myeloid malignancies in breast cancer survivors to a contemporaneous control group.

METHODS

Medical records of all patients with a history of breast cancer who received allogeneic stem cell transplants at a single, tertiary referral Comprehensive Cancer Center between 2002 and 2019 were reviewed. Transplant outcomes were compared to 289 control patients without a history of breast cancer from the same time period. Main outcomes included survival, disease-free survival, non-relapse mortality, relapse or progression of hematologic malignancy, and incidence of recurrent breast cancer after hematopoietic cell transplantation. Comparisons between women with a history of breast cancer and controls utilized propensity score weighting to balance patient characteristics.

RESULTS

Forty women, ages 30-74 years, with a history of breast cancer received an allogeneic hematopoietic cell transplant for a hematologic malignancy between December 2002 and February 2019. Twelve of the 40 patients are alive with a median survival of 7.4 years (range, 1.9-16.8 years). None of the patients had evidence of recurrent breast cancer prior to death or date of last contact. In multivariable Cox models, all transplant outcomes were similar between the patients and the control group with hematopoietic cell transplant comorbidity score as the most important confounding factor for adjustment in these models.

CONCLUSION

A history of treated breast cancer should not exclude patients from consideration for allogeneic hematopoietic cell transplantation.

How Do the Outcomes of Radiation-Associated Pelvic and Sacral Bone Sarcomas Compare to Primary Osteosarcomas following Surgical Resection?

Radiation-associated sarcoma of the pelvis and/or sacrum (RASB) is a rare but challenging disease process associated with a poor prognosis. We hypothesized that patients with RASB would have worse surgical and oncologic outcomes than patients diagnosed with primary pelvic or sacral bone sarcomas. This was a retrospective, multi-institution, comparative analysis. We reviewed surgically treated patients from multiple tertiary care centers who were diagnosed with a localized RASB. We also identified a comparison group including all patients diagnosed with a primary localized pelvic or sacral osteosarcoma/spindle cell sarcoma of bone (POPS). There were 35 patients with localized RASB and 73 patients with POPS treated with surgical resection. Patients with RASB were older than those with POPS (57 years vs. 38 years, p < 0.001). Patients with RASB were less likely to receive chemotherapy (71% for RASB vs. 90% for POPS, p = 0.01). Seventeen percent of patients with RASB died in the perioperative period (within 90 days of surgery) as compared to 4% with POPS (p = 0.03). Five-year disease-specific survival (DSS) (31% vs. 54% p = 0.02) was worse for patients with RASB vs. POPS. There was no difference in 5-year local recurrence free survival (LRFS) or metastasis free survival (MFS). RASB and POPS present challenging disease processes with poor oncologic outcomes. Rates of perioperative mortality and 5-year DSS are worse for RASB when compared to POPS.

Long-Term Results of Postoperative Hypofractionated Accelerated Breast and Lymph Node Radiotherapy (HypoAR) with Hypofractionated Boost

We report long-term results (median follow-up 12 years) of hypofractionated accelerated radiotherapy (HypoAR) in patients treated with breast-conserving surgery. In total, 367 women were treated with HypoAR. Axillary and supraclavicular area (ASA) were treated in patients with involved nodes. In total, 290 patients (scheme A) received 3.5 Gy/day ×10 fractions (breast/ASA) followed by two 4 Gy fractions with electrons to the affected breast quadrant within 16 days. In total, 77 patients (Scheme B) received 2.7 Gy/day for 16 consecutive fractions (breast/ASA) within 22 days, while concurrently, the affected breast quadrant received an electron booster dose of 0.8 Gy for the first 13 fractions. Amifostine was offered to 252/367 patients. Early radiation toxicity was minimal. Regarding late toxicities, symptomatic breast edema was noted in 2.2%, asymptomatic breast fibrosis in 1.9%, and arm lymphedema in 3.7% of patients. Amifostine reduced early radiation dermatitis (p = 0.001). In total, 2.2% of patients developed contralateral breast and 1.6% other carcinomas. Locoregional recurrence (LR) occurred in 3.1% of patients (0% for in situ carcinomas). Positive margins after surgery, extracapsular node invasion, and HER2-enriched/triple-negative tumors were linked with significantly worse LR-free survival. The involvement of more than three nodes and luminal type other than A were independent prognostic variables of metastasis and death events. HypoAR delivering a biological dose of 50–52 Gy to the breast/ASA is a safe and effective therapy for patients treated with conservative surgery. The risk of carcinogenesis is low. Positive surgical margins, extracapsular node invasion, and HER2-enriched/triple-negative phenotypes appear as a cluster of features linked with a higher risk for locoregional relapse.

Osteosarcoma of the sternum after radiotherapy for breast cancer in a patient with suspected hereditary cancer syndrome: a case report

Introduction:

Radiation-induced malignancies are a rare phenomenon. Post-radiation sarcoma accounts for 0·5–5·5% of all sarcomas. Adjuvant radiotherapy (RT) after surgery plays a significant role in the treatment of breast cancer. Sarcomas of the breast, chest wall, sternum, axilla or supraclavicular region have been reported as a rare complication of RT for breast cancer. Osteosarcoma (OS) of the sternal bone is a rarely reported entity. OS of the sternum secondary to therapeutic ionising radiation is an even rarer diagnosis, and no such cases have been reported in India as per our literature search. Here we report such a case of post-radiation sarcoma after breast cancer treatment—OS presenting in the sternum and both the second ribs in a young lady.

Findings:

Our patient developed a sarcoma within a previously irradiated field. The latent period was 7·5 years. She initially suffered from a breast carcinoma for which she underwent radical surgery in the form of modified radical mastectomy. She also received 50 Gy RT dose to the chest wall and axilla. She subsequently developed an OS of chest wall in the high-dose region of RT. Another key factor is the high possibility of familial/hereditary cancer inheritance syndrome like Li-Fraumeni in our patient. Though she was never tested for p53 mutations, her young age at first diagnosis (26 years), extremely strong positive family history and spectra of cancers affecting her first-degree blood relatives (brain tumours, leukaemia) strongly hint at the possibility of such a cancer syndrome. Retrospectively, the question certainly arises, given her young age and family history, whether this patient was a right candidate for RT even once as compared to the fact that she received radiation twice.

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.

The Management of Radiation-Induced Sarcomas: A Cohort Analysis from a Sarcoma Tertiary Center

(1) Background: Radiation-induced sarcomas (RIS) are rare diseases with poor prognoses. The aim of the study was to analyze outcomes and identify factors affecting survival in a cohort of patients with RIS. (2) Methods: We included consecutive patients with RIS that we found in the available electronic medical records of a sarcoma tertiary center. We analyzed patients’ RIS characteristics, management of RIS, the occurrence of local recurrence and distant metastases, the date of disease progression, the date of death, and the date of the last follow-up. (3) Results: Fifty-eight patients met the inclusion criteria. The most frequent sites of RIS development were the thorax and pelvis. The majority of RIS were poorly differentiated, high-grade tumors. Forty patients underwent surgery or radiotherapy with curative intent. The others were referred to palliative chemotherapy. Median progression-free survival and overall survival were 15 and 21 months, respectively. Treatment with curative intent and tumor localization on breasts and upper extremities were associated with a lower risk of death in univariate analysis. (4) Conclusions: The study confirms the poor prognosis of RIS. Treatments with locally curative intent at the tumor site are of prognostic value. Secondary radiotherapy is rarely used in RIS.

Radiation-Related Deregulation of TUBB3 and BRCA1/2 and Risk of Secondary Lung Cancer in Women With Breast Cancer

INTRODUCTION

Breast cancer survivors are at increased risk of developing unrelated primary cancers, particularly lung cancer. Evidence indicates that sex hormones as well as a deregulation of DNA-repair pathways may contribute to lung cancer onset. We investigated whether the hormone status and expression of markers involved in DNA repair (BRCA1/2, ERCC1, and P53R2), synthesis (TS and RRM1), and cell division (TUBB3) might be linked to lung cancer risk.

PATIENTS AND METHODS

Thirty-seven breast cancer survivors with unrelated lung cancer and 84 control subjects comprising women with breast cancer (42/84) or lung cancer (42/84) were enrolled. Immunohistochemistry on tumor tissue was performed. Geometric mean ratio was used to assess the association of marker levels with patient groups.

RESULTS

Estrogen receptor was expressed in approximately 90% of the breast cancer group but was negative in the majority of the lung cancer group, a result similar to the lung cancer control group. Likewise, ER isoform β was weakly expressed in the lung cancer group. Protein analysis of breast cancer versus control had a significantly lower expression of BRCA1, P53R2, and TUBB3. Likewise, a BRCA1 reduction was observed in the lung cancer group concomitant with a BRCA2 increase. Furthermore, BRCA2 and TUBB3 increased in ipsilateral lung cancer in women who had previously received radiotherapy for breast cancer.

CONCLUSION

The decrease of DNA-repair proteins in breast cancer could make these women more susceptible to therapy-related cancer. The increase of BRCA2 and TUBB3 in lung cancer from patients who previously received radiotherapy for breast cancer might reflect a tissue response to exposure to ionizing radiation.

Multiple Primary Malignant Neoplasms: An Unusual Case of Metachronous Breast Ductal and Squamous Cell Carcinomas

Multiple primary malignant neoplasms (MPMN) are generally defined as the co-occurrence of multiple primary malignant neoplasms of distinct histology in the same individual. Second and higher-order primary malignancies now comprise about 18% of all incidence of cancer in the USA. The incidence ratio of developing multiple primary cancers (MPCs) in female cancer survivors is 1.17 to 1.6. In women with breast cancer, the incidence ratio is even higher, according to age at diagnosis of breast cancer. However, the concurrence of breast cancer and squamous cell carcinoma is not described in the literature. Primary squamous cell carcinoma of bone is also rare in the skeletal system other than in the skull, with only three such cases reported in the English literature.

We present a case of a 59-year-old woman with high-grade primary invasive ductal carcinoma of the breast and second distinct squamous cell carcinoma metastasis to the bone of unknown primary site. A search for a primary squamous cell carcinoma, including CT head and neck, CT chest, colposcopy, esophagogastroduodenoscopy (EGD) and colonoscopy, did not show any evidence of a primary site.

A retrospective analysis on safety and effectiveness of hypofractioned post-mastectomy radiotherapy

The data supporting hypofractionated post-mastectomy radiotherapy is limited. The purpose of this study is to present the experience from Tarnów of hypofractionated PMRT over 20 fractions with respect to toxicity and effectiveness. We delivered post-mastectomy radiotherapy at the dose of 45 Gy in 20 fractions to the chest wall and the draining regional lymph nodes. The primary outcome of interest was to ensure that the rate of grade 3 or greater toxicity from the hypofractionation, at any time point, was non-inferior to standard post-mastectomy radiotherapy. We conducted a retrospective analysis of 211 women with stages I-IV breast cancer. After a median follow-up of 30 months, there were four reported grade 3 toxicities, with grade 3 lymphedema being the most frequent (1.5%). There were 134 reported grade 2 toxicities, with grade 2 fatigue being the most frequent (18%). There were six instances of isolated locoregional (6 of 211; 2.8%). Three-year estimated local recurrence-free survival was 96.4% (95% CI 0.921-0.984). The 3-year estimated distant recurrence-free survival was 77.8% (95% CI 0.699-0.838). To our knowledge, the results presented here are the largest single institution experience of hypofractionated post-mastectomy radiotherapy published in the literature to date. Our fractionation scheme, 45 Gy in 20 fractions, seems to be safe and effective with low toxicity.

Radical radiotherapy for locally advanced non-small cell lung cancer-what's up with arm positioning?

Radical thoracic radiotherapy is ideally delivered in the arms-up (AU) position; however, patient comfort may only allow for arms-down (AD) positioning to be feasible. Objectives of this study were (I) to evaluate the dosimetric impact of changing arm position during treatment and (II) to compare plan quality for optimization in AU vs. AD positions. In this retrospective planning study, stage III lung cancer patients (n=10) who received 60 Gy in 30 fractions using volumetric modulated arc therapy (VMAT) were identified. To simulate AD treatment, a PET/CT (acquired AD) was registered to the planning CT (acquired AU) for arm delineation. The clinically delivered plan (AU) was recalculated with a density override to 1 g/cm³ for one or both arm contours (AD). Plans were also re-optimized for the AD position. Dose-volume parameters were compared for each scenario. Moving from AU to AD without re-optimization resulted in a mean 3.7% reduction in PTV D95; in all cases, this caused 95% of the PTV to receive ≤57 Gy. The mean arms D2cc were 23.1 and 4.0 Gy for the ipsilateral and contralateral, respectively. Dosimetric consequences of ipsilateral arm only were similar to both AD, whereas contralateral arm only had less than 1% effect on PTV D95. Re-optimizing to account for both AD recovered PTV D95 coverage with acceptable doses to all organs at risk. Arm D2cc were also decreased to 5.5 and 2.3 Gy for ipsilateral and contralateral, respectively. There was a significant difference in heart V25 and mean heart dose (P<0.001), but the magnitude was small at 4.1% for V25 and 1.7 Gy for mean heart dose and the plans still met institutional dose constraints. This planning study suggests that it is feasible to plan radiotherapy for locally advanced lung cancer patients in the AD position using VMAT, when necessary, with only a modest dosimetric impact.

Integrated Somatic and Germline Whole-Exome Sequencing Analysis in Women with Lung Cancer after a Previous Breast Cancer

Women treated for breast cancer (BC) are at risk of developing secondary tumors, such as lung cancer (LC). Since rare germline variants have been linked to multiple cancer development, we hypothesized that BC survivors might be prone to develop LC as a result of harboring rare variants. Sixty patients with LC with previous BC (the study population; SP) and 53 women with either BC or LC and no secondary cancer (control population; CP) were enrolled. Whole exome sequencing was performed in both tumors and unaffected tissues from 28/60 SP patients, and in germline DNA from 32/53 CP. Candidate genes were validated in the remaining individuals from both populations. We found two main mutational signature profiles: S1 (C>T) in all BCs and 16/28 LCs, and S2 (C>A) which is strongly associated with smoking, in 12/28 LCs. The burden test over rare germline variants in S1-LC vs CP identified 248 genes. Validation confirmed GSN as significantly associated with LC in never-smokers. In conclusion, our data suggest two signatures involved in LC onset in women with previous BC. One of these signatures is linked to smoking. Conversely, regardless of smoking habit, in a subgroup of BC survivors genetic susceptibility may contribute to LC risk.

Risk factors for metachronous contralateral breast cancer: A systematic review and meta-analysis

BACKGROUND

The risk of developing metachronous contralateral breast cancer (CBC) is a recurrent topic at the outpatient clinic. We aimed to provide CBC risk estimates of published patient, pathological, and primary breast cancer (PBC) treatment-related factors.

METHODS

PubMed was searched for publications on factors associated with CBC risk. Meta-analyses were performed with grouping of studies by mutation status (i.e., BRCA1, BRCA2, CHEK2 c.1100delC), familial cohorts, and general population-based cohorts.

RESULTS

Sixty-eight papers satisfied our inclusion criteria. Strong associations with CBC were found for carrying a BRCA1 (RR = 3.7; 95%CI:2.8-4.9), BRCA2 (RR = 2.8; 95%CI:1.8-4.3) or CHEK2 c.1100delC (RR = 2.7; 95%CI:2.0-3.7) mutation. In population-based cohorts, PBC family history (RR = 1.8; 95%CI:1.2-2.6), body mass index (BMI) ≥30 kg/m² (RR = 1.5; 95%CI:1.3-1.9), lobular PBC (RR = 1.4; 95%CI:1.1-1.8), estrogen receptor-negative PBC (RR = 1.5; 95%CI:1.0-2.3) and treatment with radiotherapy <40 years (RR = 1.4; 95%CI:1.1-1.7) was associated with increased CBC risk. Older age at PBC diagnosis (RR per decade = 0.93; 95%CI:0.88-0.98), and treatment with chemotherapy (RR = 0.7; 95%CI:0.6-0.8) or endocrine therapy (RR = 0.6; 95%CI:0.5-0.7) were associated with decreased CBC risk.

CONCLUSIONS

Mutation status, family history, and PBC treatment are key factors for CBC risk. Age at PBC diagnosis, BMI, lobular histology and hormone receptor status have weaker associations and should be considered in combination with key factors to accurately predict CBC risk.

Cancer risk assessment in modern radiotherapy workflow with medical big data

Modern radiotherapy (RT) is being enriched by big digital data and intensive technology. Multimodality image registration, intelligence-guided planning, real-time tracking, image-guided RT (IGRT), and automatic follow-up surveys are the products of the digital era. Enormous digital data are created in the process of treatment, including benefits and risks. Generally, decision making in RT tries to balance these two aspects, which is based on the archival and retrieving of data from various platforms. However, modern risk-based analysis shows that many errors that occur in radiation oncology are due to failures in workflow. These errors can lead to imbalance between benefits and risks. In addition, the exact mechanism and dose-response relationship for radiation-induced malignancy are not well understood. The cancer risk in modern RT workflow continues to be a problem. Therefore, in this review, we develop risk assessments based on our current knowledge of IGRT and provide strategies for cancer risk reduction. Artificial intelligence (AI) such as machine learning is also discussed because big data are transforming RT via AI.

The use of helical tomotherapy in the treatment of early stage breast cancer: indications, tolerance, efficacy-a single center experience

PURPOSE

to evaluate our experience in terms of local control, survival, adverse effects in patients treated by adjuvant helical tomotherapy (HT) for breast cancer (BC).

RESULTS

We studied 179 consecutive patients with 194 treated breasts with adjuvant HT. Median follow-up was 38.1 months. Median age was 53 years. Chemotherapy was administered to 83% of patients. All 133 hormone receptor positive tumours received hormonal therapy. As concurrent treatment, apart from trastuzumab monotherapy, 6 patients received systemic therapy concomitant to RT. The HT was generally well tolerated with mostly grade 1 and 2 skin reactions and esophagitis. Only 3% grade III early skin reactions. At last follow-up, there were 2 local recurrences, 1 regional lymph node (LN) recurrence and 6 with metastatic progression. The 5-year progression-free survival was 90.5% (95% CI 84.2-97.3).

MATERIALS AND METHODS

A retrospective study of all patients treated by HT between 2009 and 2015 was done. Patients excluded were those with: breast implants, advanced or metastatic BC, recurrent disease. All patients received breast+/-boost or chest wall irradiation and most received with LN irradiation. Dose constraints for organs at risk were defined using optimization scale developed in our Department. Evaluation of early and late toxicity was done using Common Terminology Adverse Criteria Events v.4.0.

CONCLUSIONS

HT can be used for a well selected group of breast cancer as bilateral tumours, complex anatomy and target volumes where the conventional radiation therapy techniques cannot ensure an optimal dose distribution. Longer follow-up is necessary to confirm and validate these results.

Characterization of a novel scale maille contralateral breast shield: SMART Armor

During breast radiotherapy treatment, the contralateral breast receives radiation doses to the skin and subcutaneous tissue caused mainly from incident electron contamination and low energy photon scatter radiation. Measurements have shown that for a typical hybrid tangential treatment, these dose levels can be up to 17% of maximum applied prescription dose if no shielding is used during the treatment process. This work examined the use of different shielding metals, aluminum, copper, and lead to reduce peripheral radiation dose to evaluate the optimal metal to form the basis of a contralateral breast radiation shield. This work also shows a simple but novel method to substantially reduce this unwanted radiation dose with the use of a copper scale maille sheet which can be easily and accurately draped over a patient's contralateral breast during treatment. The copper scale maille is flexible and can thus conform around typical breast shapes. It can also form irregular shaped edges to match those outlined by typical tangential treatment fields. As the shield is made from copper, it is nontoxic and can potentially be used directly on patients for treatment. The designed copper scale maille has shown to reduce contralateral breast skin and subcutaneous dose by up to 80% for typical radiation fields used in breast radiotherapy.

Risk of secondary malignancies after radiation therapy for breast cancer: Comprehensive results

GOALS

To assess risks of secondary malignancies in breast cancer patients who received radiation therapy compared to patients who did not.

METHODS

The SEER database was used to identify females with a primary diagnosis of breast cancer as their first malignancy, during 1973-2008. We excluded patients with metastatic disease, age <18 years, no definitive surgical intervention, ipsilateral breast cancer recurrence, or who developed a secondary malignancy within 1 year of diagnosis. Standardized incidence ratios and absolute excess risk were calculated using SEER*Stat, version 8.2.1 and SAS, version 9.4.

PRINCIPLE RESULTS

There were 374,993 patients meeting the inclusion criteria, with 154,697 who received radiation therapy. With a median follow-up of 8.9 years, 13% of patients (49,867) developed a secondary malignancy. The rate of secondary malignancies was significantly greater than the endemic rate in breast cancer patients treated without radiation therapy, (O/E 1.2, 95% CI 1.19-1.22) and with radiation therapy (O/E 1.33, 95% CI 1.31-1.35). Approximately 3.4% of secondary malignancies were attributable to radiation therapy. The increased risk of secondary malignancies in breast cancer patients treated with radiation therapy compared to those without was significant regardless of age at breast cancer diagnosis (p < 0.01) and more pronounced with longer latency periods.

CONCLUSION

There was an increased risk of secondary malignancies for breast cancer patients both with and without radiation therapy compared to the general population. There was an increased risk in specific sites for patients treated with radiation therapy. This risk was most evident in young patients and who had longer latency periods.

Soft-Tissue Sarcoma following Traumatic Injury: Case Report and Review of the Literature

Soft-tissue sarcomas (STSs) are a heterogeneous group of tumors, which accounts for 1–2% of adult cancers worldwide. Despite quite a few reports on traumatic events followed by STS formation, the link between the two events remains a point of controversy. In this paper, we present the case of a young patient who had a rhabdomyosarcoma in the lower extremity, which had developed in the same location where the patient was wounded by a gunshot 9 years earlier. X-ray and CT scans clearly showed metal fragments in the area of sarcoma formation. The patient underwent neoadjuvant chemotherapy treatment, to which the tumor was, unfortunately, unresponsive. Therefore, the patient was referred to below-knee amputation of the injured leg. There are several possible etiological factors for sarcoma development in this patient, including tissue damage and inflammation, as well as the presence of metal fragments in the tissue and the limb’s exposure to radiation during multiple imaging tests. Here, we will discuss the potential influence wielded by the injury itself, as well as its complications and its medical management on the formation of the sarcoma, in light of the current literature.

Epidemiology and Etiology of Sarcomas

Sarcomas are rare malignancies of mesenchymal origin and are broadly divided into soft tissue sarcomas and bone sarcomas. The etiology of these tumors is largely unknown, and most sarcomas are sporadic. A small subset of sarcomas is associated with certain genetic syndromes and environmental factors. Ionizing radiation is the strongest environmental factor linked to sarcoma development.

Accelerated partial breast irradiation: Past, present, and future

Accelerated partial breast irradiation (APBI) focuses higher doses of radiation during a shorter interval to the lumpectomy cavity, in the setting of breast conserving therapy for early stage breast cancer. The utilization of APBI has increased in the past decade because of the shorter treatment schedule and a growing body of outcome data showing positive cosmetic outcomes and high local control rates in selected patients undergoing breast conserving therapy. Technological advances in various APBI modalities, including intracavitary and interstitial brachytherapy, intraoperative radiation therapy, and external beam radiation therapy, have made APBI more accessible in the community. Results of early APBI trials served as the basis for the current consensus guidelines, and multiple prospective randomized clinical trials are currently ongoing. The pending long term results of these trials will help us identify optimal candidates that can benefit from ABPI. Here we provide an overview of the clinical and cosmetic outcomes of various APBI techniques and review the current guidelines for selecting suitable breast cancer patients. We also discuss the impact of APBI on the economics of cancer care and patient reported quality of life.

Mouse models for radiation-induced cancers

Potential ionising radiation exposure scenarios are varied, but all bring risks beyond the simple issues of short-term survival. Whether accidentally exposed to a single, whole-body dose in an act of terrorism or purposefully exposed to fractionated doses as part of a therapeutic regimen, radiation exposure carries the consequence of elevated cancer risk. The long-term impact of both intentional and unintentional exposure could potentially be mitigated by treatments specifically developed to limit the mutations and precancerous replication that ensue in the wake of irradiation The development of such agents would undoubtedly require a substantial degree of in vitro testing, but in order to accurately recapitulate the complex process of radiation-induced carcinogenesis, well-understood animal models are necessary. Inbred strains of the laboratory mouse, Mus musculus, present the most logical choice due to the high number of molecular and physiological similarities they share with humans. Their small size, high rate of breeding and fully sequenced genome further increase its value for use in cancer research. This chapter will review relevant m. musculus inbred and F1 hybrid animals of radiation-induced myeloid leukemia, thymic lymphoma, breast and lung cancers. Method of cancer induction and associated molecular pathologies will also be described for each model.

Helical tomotherapy and volumetric modulated arc therapy: New therapeutic arms in the breast cancer radiotherapy

AIM

To analyse clinical and dosimetric results of helical tomotherapy (HT) and volumetric modulated arc therapy (VMAT) in complex adjuvant breast and nodes irradiation.

METHODS

Seventy-three patients were included (31 HT and 42 VMAT). Dose were 63.8 Gy (HT) and 63.2 Gy (VMAT) in the tumour bed, 52.2 Gy in the breast, 50.4 Gy in supraclavicular nodes (SCN) and internal mammary chain (IMC) with HT and 52.2 Gy and 49.3 Gy in IMC and SCN with VMAT in 29 fractions. Margins to particle tracking velocimetry were greater in the VMAT cohort (7 mm vs 5 mm).

RESULTS

For the HT cohort, the coverage of clinical target volumes was as follows: Tumour bed: 99.4% ± 2.4%; breast: 98.4% ± 4.3%; SCN: 99.5% ± 1.2%; IMC: 96.5% ± 13.9%. For the VMAT cohort, the coverage was as follows: Tumour bed: 99.7% ± 0.5%, breast: 99.3% ± 0.7%; SCN: 99.6% ± 1.4%; IMC: 99.3% ± 3%. For ipsilateral lung, Dmean and V20 were 13.6 ± 1.2 Gy, 21.1% ± 5% (HT) and 13.6 ± 1.4 Gy, 20.1% ± 3.2% (VMAT). Dmean and V30 of the heart were 7.4 ± 1.4 Gy, 1% ± 1% (HT) and 10.3 ± 4.2 Gy, 2.5% ± 3.9% (VMAT). For controlateral breast Dmean was 3.6 ± 0.2 Gy (HT) and 4.6 ± 0.9 Gy (VMAT). Acute skin toxicity grade 3 was 5% in the two cohorts.

CONCLUSION

HT and VMAT in complex adjuvant breast irradiation allow a good coverage of target volumes with an acceptable acute tolerance. A longer follow-up is needed to assess the impact of low doses to healthy tissues.

5-year results of accelerated partial breast irradiation using sole interstitial multicatheter brachytherapy versus whole-breast irradiation with boost after breast-conserving surgery for low-risk invasive and in-situ carcinoma of the female breast: a randomised, phase 3, non-inferiority trial

BACKGROUND

In a phase 3, randomised, non-inferiority trial, accelerated partial breast irradiation (APBI) for patients with stage 0, I, and IIA breast cancer who underwent breast-conserving treatment was compared with whole-breast irradiation. Here, we present 5-year follow-up results.

METHODS

We did a phase 3, randomised, non-inferiority trial at 16 hospitals and medical centres in seven European countries. 1184 patients with low-risk invasive and ductal carcinoma in situ treated with breast-conserving surgery were centrally randomised to either whole-breast irradiation or APBI using multicatheter brachytherapy. The primary endpoint was local recurrence. Analysis was done according to treatment received. This trial is registered with ClinicalTrials.gov, number NCT00402519.

FINDINGS

Between April 20, 2004, and July 30, 2009, 551 patients had whole-breast irradiation with tumour-bed boost and 633 patients received APBI using interstitial multicatheter brachytherapy. At 5-year follow-up, nine patients treated with APBI and five patients receiving whole-breast irradiation had a local recurrence; the cumulative incidence of local recurrence was 1.44% (95% CI 0.51-2.38) with APBI and 0.92% (0.12-1.73) with whole-breast irradiation (difference 0.52%, 95% CI -0.72 to 1.75; p=0.42). No grade 4 late side-effects were reported. The 5-year risk of grade 2-3 late side-effects to the skin was 3.2% with APBI versus 5.7% with whole-breast irradiation (p=0.08), and 5-year risk of grade 2-3 subcutaneous tissue late side-effects was 7.6% versus 6.3% (p=0.53). The risk of severe (grade 3) fibrosis at 5 years was 0.2% with whole-breast irradiation and 0% with APBI (p=0.46).

INTERPRETATION

The difference between treatments was below the relevance margin of 3 percentage points. Therefore, adjuvant APBI using multicatheter brachytherapy after breast-conserving surgery in patients with early breast cancer is not inferior to adjuvant whole-breast irradiation with respect to 5-year local control, disease-free survival, and overall survival.

FUNDING

German Cancer Aid.

Non-small-cell lung cancer after breast cancer: a population-based study of clinicopathologic characteristics and survival outcomes in 3529 women

INTRODUCTION

Annually, 1.4 million women worldwide are diagnosed with breast cancer (BC) and are at risk for another common malignancy: non-small-cell lung cancer (NSCLC). No large population-based study has examined subsequent survival.

METHODS

Women with histologically confirmed NSCLC after BC (BC-NSCLC, n = 3529) were identified in SEER-18 registries (1988-2009). Clinicopathologic characteristics and survival outcomes were compared among women with first primary NSCLC (NSCLC-1, n = 151,628). Cox regression analyses were adjusted for patient, BC, and NSCLC factors.

RESULTS

BC-NSCLC was diagnosed at earlier stages (34% localized, 30% regional, 36% distant) than NSCLC-1 (22%, 28%, and 50%, respectively; p < 0.0001). For localized and regional BC-NSCLC, surgical resection rates were higher than NSCLC-1 (72% versus 69% [p < 0.01] and 56% versus 46% [p < 0.0001]), respectively). Radiotherapy was given less often for BC-NSCLC than NSCLC-1 (localized: 15% versus 18%, p < 0.004; regional: 38% versus 49%, p < 0.0001). Median overall survival (OS) after localized, regional, and distant BC-NSCLC was 5.1 years, 1.9 years, and 5.8 months, respectively. For NSCLC-1, median OS was 4.6 years, 1.5 years, and 4.6 months, respectively. BC history did not affect OS for localized NSCLC, and OS was modestly greater after regional (p = 0.016) and distant (p < 0.0001) BC-NSCLC compared with NSCLC-1. BC radiotherapy to the ipsilateral chest did not unfavorably influence OS.

CONCLUSIONS

BC survivors are more likely to be diagnosed with earlier stage NSCLC versus first primary NSCLC patients, perhaps reflecting heightened surveillance compared with the general population. In contrast to prior studies of NSCLC in survivors of lymphopoietic malignancies, BC history does not appear to adversely affect OS after NSCLC.

Adjuvant Radiotherapy after Breast Conserving Treatment for Breast Cancer: A Dosimetric Comparison between Volumetric Modulated Arc Therapy and Intensity Modulated Radiotherapy

BACKGROUND

Radiotherapy is an important treatment of choice for breast cancer patients after breast- conserving surgery, and we compare the feasibility of using dual arc volumetric modulated arc therapy (VMAT2), single arc volumetric modulated arc therapy (VMAT1) and Multi-beam Intensity Modulated Radiotherapy (M-IMRT) on patients after breast-conserving surgery.

MATERIALS AND METHODS

Thirty patients with breast cancer (half right-sided and half left-sided) treated by conservative lumpectomy and requiring whole breast radiotherapy with tumor bed boost were planned with three different radiotherapy techniques: 1) VMAT1; 2) VMAT2; 3) M-IMRT. The distributions for the planning target volume (PTV) and organs at risk (OARs) were compared. Dosimetries for all the techniques were compared.

RESULTS

All three techniques satisfied the dose constraint well. VMAT2 showed no obvious difference in the homogeneity index (HI) and conformity index (CI) of the PTV with respect to M-IMRT and VMAT1. VMAT2 clearly improved the treatment efficiency and can also decrease the mean dose and V5Gy of the contralateral lung. The mean dose and maximum dose of the spinal cord and contralateral breast were lower for VMAT2 than the other two techniques. The very low dose distribution (V1Gy) of the contralateral breast also showed great reduction in VMAT2 compared with the other two techniques. For the ipsilateral lung of right-sided breast cancer, the mean dose was decreased significantly in VMAT2 compared with VMAT1 and M-IMRT. The V20Gy and V30Gy of the ipsilateral lung of the left- sided breast cancer for VMAT2 showed obvious reduction compared with the other two techniques. The heart statistics of VMAT2 also decreased considerably compared to VMAT1 and M-IMRT.

CONCLUSIONS

Compared to the other two techniques, the dual arc volumetric modulated arc therapy technique reduced radiation dose exposure to the organs at risk and maintained a reasonable target dose distribution.

Can c-myc amplification reliably discriminate postradiation from primary angiosarcoma of the breast?

PURPOSE

Breast angiosarcomas are rare vascular malignancies that arise secondary to irradiation or de novo as primary tumours. The aim of this study is to know whether c-myc amplification can reliably discriminate these two entities.

MATERIEL AND METHODS

Forty-seven patients treated for breast angiosarcomas were studied. Thirty-two patients were diagnosed with postradiation angiosarcomas after breast cancer treatment and 15 patients with primary angiosarcomas. Interphase fluorescence in situ hybridization (FISH) was performed by hybridization of probes covering C-MYC (chromosome 8q24.21) and CEP8 on tissue sections.

RESULTS

Amplification (5- to 20-fold) of the c-myc oncogene was found in all breast radiation-induced angiosarcomas (32 tumours) but in none of the 15 primary angiosarcomas except one (7%).

CONCLUSION

This study reinforces that there are true pathogenetic differences between the two types of breast angiosarcomas which are morphologically indistinguishable. These data point the pathways preferentially involved in the pathogenesis of post radiation angiosarcomas of the breast and may provide the basis for an additional targeted therapy.

Angiosarcoma in previously irradiated breast in patient with Li-Fraumeni syndrome. A case report

CONTEXT

Li-Fraumeni syndrome is a rare disease with an autosomal dominant inheritance pattern and high penetrance that defines a 50% chance of developing cancer before the age of 30 years, including cases of breast sarcoma. Patients with this syndrome who require radiotherapy have an increased risk of developing secondary malignancies including angiosarcomas.

CASE REPORT

This was a case report on a female patient with Li-Fraumeni syndrome. In October 2005, she was diagnosed with invasive ductal carcinoma of the right breast and underwent sectorectomy. She then received chemotherapy and adjuvant radiotherapy. Trastuzumab and tamoxifen were also part of the treatment. She recently sought care at our hospital, complaining of hyperemia and nodulation in the right breast, and underwent surgical resection that revealed epithelioid angiosarcoma.

CONCLUSIONS

When genetic predisposition due to Li-Fraumeni syndrome is documented, the therapy should be adapted so as to minimize the risk. Thus, conservative surgical treatments should be avoided and mastectomy without radiation should be prioritized. In cases in which use of radiotherapy is justified, patients should be followed up intensively.

Minimizing second cancer risk following radiotherapy: current perspectives

Secondary cancer risk following radiotherapy is an increasingly important topic in clinical oncology with impact on treatment decision making and on patient management. Much of the evidence that underlies our understanding of secondary cancer risks and our risk estimates are derived from large epidemiologic studies and predictive models of earlier decades with large uncertainties. The modern era is characterized by more conformal radiotherapy technologies, molecular and genetic marker approaches, genome-wide studies and risk stratifications, and sophisticated biologically based predictive models of the carcinogenesis process. Four key areas that have strong evidence toward affecting secondary cancer risks are 1) the patient age at time of radiation treatment, 2) genetic risk factors, 3) the organ and tissue site receiving radiation, and 4) the dose and volume of tissue being irradiated by a particular radiation technology. This review attempts to summarize our current understanding on the impact on secondary cancer risks for each of these known risk factors. We review the recent advances in genetic studies and carcinogenesis models that are providing insight into the biologic processes that occur from tissue irradiation to the development of a secondary malignancy. Finally, we discuss current approaches toward minimizing the risk of radiation-associated secondary malignancies, an important goal of clinical radiation oncology.

Risk of second non-breast cancer after radiotherapy for breast cancer: a systematic review and meta-analysis of 762,468 patients

BACKGROUND AND PURPOSE

Radiotherapy for breast cancer both decreases loco-regional recurrence rates and improves overall survival. However, radiotherapy has also been associated with increased second cancer risk at exposed sites. In this meta-analysis, we estimated the risk of second non-breast cancers after radiotherapy for breast cancer.

MATERIAL AND METHODS

The databases Medline/Pubmed, Cochrane, Embase and Cinahl were systematically searched, for cohort studies on second cancer after radiotherapy for breast cancer, from inception to August 1st 2013. Included studies were to report the relative risk (RR) of second cancers comparing irradiated female breast cancer patients to unirradiated patients. Primary endpoints were all second non-breast-cancers and second cancers of the lung, esophagus, thyroid and second sarcomas. RRs were pooled using random-effects meta-analysis.

RESULTS

Thirteen studies comprising 762,468 breast cancer patients were included in the meta-analysis. Five or more years after breast cancer diagnosis radiotherapy was significantly associated with an increased risk of second non-breast cancer RR 1.12 (95% confidence interval [CI] 1.06-1.19), second cancer of the lung RR 1.39 (95% CI 1.28-1.51), esophagus RR 1.53 (95% CI 1.01-2.31) and second sarcomas RR 2.53 (95% CI 1.74-3.70). The risk increased over time, and was highest 15 or more years after breast cancer diagnosis, for second lung RR 1.66 (95% CI 1.36-2.01) and second esophagus cancer RR 2.17 (95% CI 1.11-4.25). There was no significant association between radiotherapy and second thyroid cancer.

CONCLUSIONS

Radiotherapy for breast cancer is significantly associated with increased risks of second non-breast cancer, overall and in organs adjacent to the previous treatment fields. Despite a relative small absolute risk, the growing number of long-time survivors after breast cancer warrants the need for normal tissue sparing radiotherapy techniques.

Second malignant neoplasms and cardiovascular disease following radiotherapy

Second malignant neoplasms (SMNs) and cardiovascular disease (CVD) are among the most serious and life-threatening late adverse effects experienced by the growing number of cancer survivors worldwide and are due in part to radiotherapy. The National Council on Radiation Protection and Measurements (NCRP) convened an expert scientific committee to critically and comprehensively review associations between radiotherapy and SMNs and CVD, taking into account radiobiology; genomics; treatment (i.e., radiotherapy with or without chemotherapy and other therapies); type of radiation; and quantitative considerations (i.e., dose-response relationships). Major conclusions of the NCRP include: (1) the relevance of older technologies for current risk assessment when organ-specific absorbed dose and the appropriate relative biological effectiveness are taken into account and (2) the identification of critical research needs with regard to newer radiation modalities, dose-response relationships, and genetic susceptibility. Recommendation for research priorities and infrastructural requirements include (1) long-term large-scale follow-up of extant cancer survivors and prospectively treated patients to characterize risks of SMNs and CVD in terms of radiation dose and type; (2) biological sample collection to integrate epidemiological studies with molecular and genetic evaluations; (3) investigation of interactions between radiotherapy and other potential confounding factors, such as age, sex, race, tobacco and alcohol use, dietary intake, energy balance, and other cofactors, as well as genetic susceptibility; (4) focusing on adolescent and young adult cancer survivors, given the sparse research in this population; and (5) construction of comprehensive risk prediction models for SMNs and CVD to permit the development of follow-up guidelines and prevention and intervention strategies.

Low-dose-area-constrained helical TomoTherapy-based whole breast radiotherapy and dosimetric comparison with tangential field-in-field IMRT

Background and Purpose. To present a novel helical TomoTherapy-based method for whole breast radiotherapy that has better dosimetry and also has acceptable low-dose regions for lungs, heart, and contralateral breast compared with tangential field-in-field IMRT (FIF-IMRT). Material and Methods. Ten patients with left-side breast cancer were planned with low-dose-area-constrained helical TomoTherapy (LDC-HT) and FIF-IMRT. Dosimetry was compared for all techniques. Results. Coverage of the whole breast was adequate with both techniques. Homogeneity index (HI) and conformity index (CI) were better with LDC-HT. LDC-HT showed dosimetry advantages over FIF-IMRT for ipsilateral lung and heart in not only high-dose levels but also in low-dose levels such as V_10 Gy and V_5 Gy. For contralateral lung, both techniques can provide good protection, although the mean dose of LDC-HT is higher than that of FIF-IMRT. Conclusions. With LDC-HT, we obtained adequate target coverage, better HI and CI of target volume, better sparing of organs at risk, and acceptably low-dose areas compared with FIF-IMRT. LDC-HT could be a feasible method in whole breast radiotherapy. Clinical benefits of LDC-HT need further investigation.

Postmastectomy radiation therapy: an overview for the practicing surgeon

Locoregional control of breast cancer is the shared domain and responsibility of surgeons and radiation oncologists. Because surgeons are often the first providers to discuss locoregional control and recurrence risks with patients and because they serve in a key gatekeeping role as referring providers for radiation therapy, a sophisticated understanding of the evidence regarding radiotherapy in breast cancer management is essential for the practicing surgeon. This paper synthesizes the complex and evolving evidence regarding the role of radiation therapy after mastectomy. Although substantial evidence indicates that radiation therapy can reduce the risk of locoregional failure after mastectomy (with a relative reduction of risk of approximately two-thirds), debate persists regarding the specific subgroups who have sufficient risks of residual microscopic locoregional disease after mastectomy to warrant treatment with radiation. This paper reviews the evidence available to guide appropriate referral and patient decision making, with special attention to areas of controversy, including patients with limited nodal disease, those with large tumors but negative nodes, node-negative patients with high risk features, patients who have received systemic chemotherapy in the neoadjuvant setting, and patients who may wish to integrate radiation therapy with breast reconstruction surgery.

Endometrial pathology in breast cancer patients: Effect of different treatments on ultrasonographic, hysteroscopic and histological findings

Breast cancer patients have an increased risk of endometrial pathology. To investigate whether the incidence of endometrial abnormalities and their clinicopathological features were affected by receiving tamoxifen (TAM), non-steroidal aromatase inhibitors (AIs) or no treatment (NT), 333 peri/postmenopausal breast cancer patients, who were referred to the Department of Gynecological, Obstetrical Sciences and Reproductive Medicine for gynecological assessment, were reviewed retrospectively. Transvaginal ultrasonographic (TVUS), hysteroscopic and histological findings were investigated. Endometrial histological findings included: atrophy in 61, 94.3 and 55.6% of cases in the TAM, AIs and NT groups, respectively; polyps in 30.9, 31.4 and 42.2% of cases in the TAM, AIs and NT groups, respectively; hyperplasia in 3% of patients in the TAM group and 11.1% of patients in the NT group; and cancer in 3.8% of cases in the TAM group and 11.1% of cases in the NT group. There was a significant correlation between the duration of TAM treatment and the severity of endometrial pathology. In all groups, there was a significant correlation between hysteroscopic and histological findings with regard to the diagnosis of endometrial atrophy, polyps, hyperplasia and cancer (P<0.001). In conclusion, these data revealed that there was a higher incidence of endometrial pathology in the NT group compared with the TAM group, which was significant for endometrial hyperplasia and cancer. The chance of developing high-risk histological subtypes of endometrial cancer was independent of TAM use. Lastly, although there was no significant difference in recurrent vaginal bleeding and mean endometrial thickness between the TAM and AIs groups, patients receiving AIs did not exhibit hyperplastic, dysplastic or neoplastic changes in the endometrium. This study indicates that breast cancer patients require screening for endometrial pathology; TVUS alone is useful in asymptomatic patients, however, in patients where the endometrial line is irregular or its thickness is >3 mm, hysteroscopy with directed biopsy is the appropriate diagnostic method.

Mouse models of radiation-induced cancers

Radiation-induced (RI) secondary cancers were not a major clinical concern even as little as 15 years ago. However, advances in cancer diagnostics, therapy, and supportive care have saved numerous lives and many former cancer patients are now living for 5, 10, 20, and more years beyond their initial diagnosis. The majority of these patients have received radiotherapy as a part of their treatment regimen and are now beginning to develop secondary cancers arising from normal tissue exposure to damaging effects of ionizing radiation. Because historically patients rarely survived past the extended latency periods inherent to these RI cancers, very little effort was channeled towards the research leading to the development of therapeutic agents intended to prevent or ameliorate oncogenic effects of normal tissue exposure to radiation. The number of RI cancers is expected to increase very rapidly in the near future, but the field of cancer biology might not be prepared to address important issues related to this phenomena. One such issue is the ability to accurately differentiate between primary tumors and de novo arising secondary tumors in the same patient. Another issue is the lack of therapeutic agents intended to reduce such cancers in the future. To address these issues, large-scale epidemiological studies must be supplemented with appropriate animal modeling studies. This work reviews relevant mouse (Mus musculus) models of inbred and F1 animals and methodologies of induction of most relevant radiation-associated cancers: leukemia, lymphoma, and lung and breast cancers. Where available, underlying molecular pathologies are included.

Mouse models for efficacy testing of agents against radiation carcinogenesis—a literature review

As the number of cancer survivors treated with radiation as a part of their therapy regimen is constantly increasing, so is concern about radiation-induced cancers. This increases the need for therapeutic and mitigating agents against secondary neoplasias. Development and efficacy testing of these agents requires not only extensive in vitro assessment, but also a set of reliable animal models of radiation-induced carcinogenesis. The laboratory mouse (Mus musculus) remains one of the best animal model systems for cancer research due to its molecular and physiological similarities to man, small size, ease of breeding in captivity and a fully sequenced genome. This work reviews relevant M. musculus inbred and F₁ hybrid animal models and methodologies of induction of radiation-induced leukemia, thymic lymphoma, breast, and lung cancer in these models. Where available, the associated molecular pathologies are also included.