Cullin3-KLHL25 ubiquitin ligase targets ACLY for degradation to inhibit lipid synthesis and tumor progression.

Increased lipid synthesis is a key characteristic of many cancers that is critical for cancer progression. ATP-citrate lyase (ACLY), a key enzyme for lipid synthesis, is frequently overexpressed or activated in cancer to promote lipid synthesis and tumor progression. Cullin3 (CUL3), a core protein for the CUL3-RING ubiquitin ligase complex, has been reported to be a tumor suppressor and frequently down-regulated in lung cancer. Here, we found that CUL3 interacts with ACLY through its adaptor protein, KLHL25 (Kelch-like family member 25), to ubiquitinate and degrade ACLY in cells. Through negative regulation of ACLY, CUL3 inhibits lipid synthesis, cell proliferation, and xenograft tumor growth of lung cancer cells. Furthermore, ACLY inhibitor SB-204990 greatly abolishes the promoting effect of CUL3 down-regulation on lipid synthesis, cell proliferation, and tumor growth. Importantly, low CUL3 expression is associated with high ACLY expression and poor prognosis in human lung cancer. In summary, our results identify CUL3-KLHL25 ubiquitin ligase as a novel negative regulator for ACLY and lipid synthesis and demonstrate that decreased CUL3 expression is an important mechanism for increased ACLY expression and lipid synthesis in lung cancer. These results also reveal that negative regulation of ACLY and lipid synthesis is a novel and critical mechanism for CUL3 in tumor suppression.

Clinical efficacy of PARP inhibitors in breast cancer.

BRCA1 and BRCA2 are key tumor suppressor genes that are essential for the homologous recombination DNA repair pathway. Loss of function mutations in these genes result in hereditary breast and ovarian cancer syndromes, which comprise approximately 5% of cases. BRCA1/2 mutations are associated with younger age of diagnosis and increased risk of recurrences. The concept of synthetic lethality led to the development of PARP inhibitors which cause cell cytotoxicity via the inhibition of PARP1, a key DNA repair protein, in cells with germline BRCA1/2 mutations. Although still poorly understood, the most well-acknowledged proposed mechanisms of action of PARP1 inhibition include the inhibition of single strand break repair, PARP trapping, and the upregulation of non-homologous end joining. Olaparib and talazoparib are PARP inhibitors that have been approved for the management of HER2-negative breast cancer in patients with germline BRCA1/2 mutations. This review article highlights the clinical efficacy of PARP inhibitors in patients with HER2-negative breast cancer in early and advanced settings.

Utilization of radiation therapy and predictors of noncompliance among Syrian refugees in Turkey.

BACKGROUND: Access to cancer care is a problem that continues to plague refugees displaced from their home countries. The turbulent political crisis in Syria, which has led to millions of refugees seeking asylum in Turkey, merits further attention. We aimed to study the rate of utilization of radiation therapy among Syrian refugees with cancer living in Turkey in an attempt to identify the contributing factors predictive of non-compliance with prescribed RT. METHODS: In this retrospective review of 14 institutional databases, Syrian refugee patients in Turkey with a cancer diagnosis from January 2015 to December 2019 who were treated with RT were identified. The demographic data, treatment compliance rates, and toxicity outcomes in these patients were surveyed. Variable predictors of noncompliance such as age, sex, diagnosis, treatment length, and toxicity were studied. The association between these variables and patient noncompliance was determined. RESULTS: We identified 10,537 patients who were diagnosed with cancer during the study period, of whom 1010 (9.6%) patients were treated with RT. Breast cancer (30%) and lung cancer (14%) were the most common diagnoses with up to 68% of patients diagnosed at an advanced stage (Stage III, IV). 20% of the patients were deemed noncompliant. Treatment with concurrent chemoradiotherapy (OR 1.61, 95% CI 1.06-2.46, p = 0.023) and living in a refugee camp (OR 3.62, 95% CI 2.43-5.19, p < 0.001) were associated with noncompliance. Age, sex and treatment length were not significantly associated with noncompliance. CONCLUSIONS: Noncompliance with radiotherapy among Syrian refugees in Turkey remains an area of concern with a multitude of factors contributing to these alarming numbers. Further studies to better ascertain the finer nuances of this intricately complex problem and a global combination of efforts can pave the way to providing a solution.

Patterns of postmastectomy radiation therapy in clinically node-positive breast cancerpatients with pathologically negative lymph nodes after neoadjuvant chemotherapy.

BACKGROUND: To analyze postmastectomy radiation therapy (PMRT) utilization and its association with overall survival (OS) in patients presenting with node-positive breast cancer who are pathologically node-negative (ypN0) after neoadjuvant chemotherapy (NAC). METHODS: Using the National Cancer Data Base (NCDB), we identified patients diagnosed between 2004 and 2013 with clinical T1-4 node-positive nonmetastatic breast cancer who received NAC and underwent mastectomy with pathologically negative lymph node sampling. Multivariable regression models identified factors associated with PMRT use. The Cox proportional hazards model was used to evaluate predictors of mortality. RESULTS: The study included 8766 clinically node-positive patients who met the study criteria. PMRT was delivered to 61.5% of patients. Overall PMRT utilization rate increased over the study period from 54.4% in 2004 to 65.2% in 2011. Predictors of PMRT use included larger tumor size, increasing clinical N stage, higher grade disease, receipt of hormone therapy, and a greater number of lymph nodes examined. The unadjusted 5-year OS was 84.1% in the PMRT group and 83.8% in the non-PMRT group (p = NS). PMRT was not significantly associated with survival on multivariable analysis (hazard ratio [HR] 0.87; 95% confidence interval [CI] 0.73-1.03). DISCUSSION: The delivery of PMRT has increased over time in women presenting with clinically node-positive breast cancer who convert to ypN0 after NAC. While we identified multiple independent socioeconomic and clinical predictors of both PMRT utilization and survival, PMRT itself was not significantly associated with survival.

Incidence of clinical lymphedema in breast cancer patients treated with adjuvant proton-based radiotherapy.

Background: The purpose of this study was to evaluate the incidence of clinical lymphedema following adjuvant proton-based radiotherapy (RT) in breast cancer (BC) patients. Materials and methods: We performed a retrospective review of our institutional database to identify BC patients treated with adjuvant proton-based RT. Patients receiving re-irradiation for a BC recurrence or those with a history of ipsilateral chest wall radiation were excluded. Clinical lymphedema was determined by documentation in the chart at baseline and during follow-up. Results: We identified 28 patients treated with adjuvant proton-based RT who met the study criteria. Median age at diagnosis was 45 (range, 24-75). Eleven patients (39%) underwent mastectomy, and fourteen (50%) underwent axillary lymph node dissection (ALND). Median number of LNs removed was 6 (range, 1-28). Nineteen patients (68%) received neoadjuvant chemotherapy. Median whole breast/chest wall dose delivered was 50 Gy (range, 44-54.0 Gy). Target volumes included the axillary and supraclavicular lymph nodes in all patients and internal mammary lymph nodes in 27 (96%) patients. Mean dose to the axilla was 49.7 Gy, and mean dose to 95% of the axillary volume (D95) was 46.3 Gy (94% of prescription dose). Mean dose to supraclavicular (SCV) volume was 47.7 Gy, and D95 was 44.1 Gy (91% of prescription dose). Grade 3 dermatitis occurred in 14% of patients. Five patients (18%) had clinical lymphedema, 4 from the ALND subset (n = 14). Conclusions: The incidence of clinical lymphedema after proton-based RT is comparable to rates reported with photon-based RT with comprehensive nodal coverage.

SARS-CoV-2 nosocomial infection: Real-world results of environmental surface testing from a large tertiary cancer center.

BACKGROUND: Despite consensus guidelines, concern about severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission has dissuaded patients with cancer from seeking medical care. Studies have shown that contaminated surfaces may contain viable virus for up to 72 hours in laboratory settings. The purpose of this study was to investigate contamination of SARS-CoV-2 on commonly used environmental surfaces in a tertiary cancer care center. METHODS: This study evaluated the incidence of SARS-CoV-2 viral RNA in high-touch outpatient and inpatient cancer center spaces. Surfaces were tested over a 2-week period after patient or staff exposure but before scheduled disinfection services according to the World Health Organization protocols for coronavirus disease 2019 (COVID-19) surface sampling. Samples were analyzed via reverse transcriptase-polymerase chain reaction for the presence of SARS-CoV-2 RNA. RESULTS: Two hundred four environmental samples were obtained from inpatient and outpatient oncology clinics and infusion suites, and they were categorized as 1) public areas, 2) staff areas, or 3) medical equipment. One hundred thirty surfaces from 2 outpatient hematology and oncology clinics and 36 surfaces from an inpatient leukemia/lymphoma/chimeric antigen receptor T-cell unit were examined, and all 166 samples were negative for SARS-CoV-2. One of 38 samples (2.6%) from COVID-19+ inpatient units was positive. Altogether, the positive test rate for SARS-CoV-2 RNA across all surfaces was 0.5% (1 of 204). CONCLUSIONS: This prospective, systematic quality assurance investigation of real-world environmental surfaces, performed in inpatient and outpatient hematology/oncology units, revealed overall negligible detection of SARS-CoV-2 RNA when strict mitigation strategies against COVID-19 transmission were instituted. LAY SUMMARY: The potential risks of nosocomial infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have deterred patients with cancer from seeking timely care despite consensus guidelines. This study has found negligible rates of environmental contamination with SARS-CoV-2 across a multitude of commonly used surfaces in outpatient and inpatient hematology/oncology settings with adherence to strict infection control protocols.

Extrapolation of ACOSOG Z0011 trial results-A survey of breast cancer providers.

We surveyed breast providers from a national oncology cooperative group to evaluate axillary management recommendations for patients with 1-2 positive sentinel lymph nodes (+SLNs) with scenarios not explicitly included in the Z0011 trial. These scenarios included patients underrepresented (premenopausal, HER2+/triple-negative tumors, and invasive lobular carcinoma) or excluded (treated with mastectomy or neo-adjuvant chemotherapy [NAC]) from the ACOSOG Z0011 trial. Survey response rate was 94/149 (64%). For patients in underrepresented groups, 45-63% of providers recommended no further axillary treatment. For mastectomy patients, 45-55% recommended multi-disciplinary discussion. 83% felt more data are needed to change practice, but 41% believed there would be significant accrual challenges to a clinical trial. For patients treated with NAC, recommendations varied widely. 85% felt more data are needed to change practice, but 26% felt there would be significant accrual challenges. For all scenarios, 86-100% of radiation oncologists recommended axillary radiation, while surgeons more often recommended no further axillary treatment. Traditional randomized trials are likely not feasible to provide answers to these critical management questions, so more pragmatic or big data studies may be needed.

Patterns of post-mastectomy radiation therapy in clinically node positive breast cancer patients with pathologically negative lymph nodes after neoadjuvant chemotherapy.

BACKGROUND: To analyze postmastectomy radiation therapy (PMRT) utilization and its association with overall survival (OS) in patients presenting with node positive breast cancer who are pathologically node negative (ypN0) after neoadjuvant chemotherapy (NAC). MATERIALS AND METHODS: Using the National Cancer Data Base (NCDB), we identified patients diagnosed between 2004 and 2013 with clinical T1-4 node-positive non-metastatic breast cancer who received NAC and underwent mastectomy with pathologically negative lymph node sampling. Multivariable regression models identified factors associated with PMRT use. The Cox proportional hazards model was used to evaluate predictors of mortality. RESULTS: The study included 8,766 clinically node-positive patients who met the study criteria. PMRT was delivered to 61.5% of patients. Overall PMRT utilization rate increased over the study period from 54.4% in 2004 to 65.2% in 2011. Predictors of PMRT use included larger tumor size, increasing clinical N stage, higher grade disease, receipt of hormone therapy, and greater number of lymph nodes examined. Unadjusted 5-year OS was 84.1% in the PMRT group and 83.8% in the non-PMRT group (p=NS). PMRT was not significantly associated with survival on multivariable analysis (hazard ratio [HR] 0.87; 95% confidence interval [CI] 0.73-1.03). CONCLUSION: The delivery of PMRT has increased over time in women presenting with clinically node positive breast cancer who convert to ypN0 after NAC. While we identified multiple independent socioeconomic and clinical predictors of both PMRT utilization and survival, PMRT itself was not significantly associated with survival.

Nomogram-based estimate of axillary nodal involvement in ACOSOG Z0011 (Alliance): validation and association with radiation protocol variations.

PURPOSE: A substantial proportion of patients enrolled on ACOSOG Z0011 received protocol-deviant radiation treatment. It is currently unknown whether these deviations involved the use of more extensive fields in patients at higher nomogram-predicted risk. METHODS: We used the M.D. Anderson (MDA) and Memorial Sloan-Kettering (MSK) nomograms to estimate risk of additional positive axillary nodes using surgical pathology information. In the control arm, we compared axillary dissection (AD) findings to nomogram-predicted estimates for validation. We used logistic regression to evaluate whether nomogram-estimated higher risk of nodal involvement was associated with high tangent (HT) or supraclavicular (SCV) radiation fields for patients with known radiation field design. RESULTS: 552/856 (64.5%) had complete details for the MDA nomogram. Mean MDA risk estimate in both treatment arms was 23.8%. Estimated risk for patients on the AD arm with positive nodes was 25.9%. Higher risk estimate was associated with additional positive nodes in the AD arm (OR 1.04, 95% CI 1.02-1.06, p < 0.0001). We observed significant association with higher MDA nomogram-estimated risk and SCV radiation (OR 1.07, 95% CI 1.04-1.10, p < 0.0001) but not HT (OR 0.99, 95% CI 0.96-1.02, p = 0.52) The MSK nomogram had similar associations. CONCLUSION: MDA and MSK nomogram risk estimates were associated with lymph node risk in ACOSOG Z0011. Radiation oncologists' use of differing radiation fields were associated with treating higher risk patients. ClinicalTrials.gov id: NCT00003854.

Cosmetic Outcomes Following Breast-Conservation Surgery and Radiation for Multiple Ipsilateral Breast Cancer: Data from the Alliance Z11102 Study.

BACKGROUND: Diagnoses of multiple ipsilateral breast cancer (MIBC) are increasing. Historically, the primary treatment for MIBC has been mastectomy due to concerns about in-breast recurrence risk and poor cosmetic outcome. The Alliance Z11102 study prospectively assessed cosmetic outcomes in women with MIBC treated with breast-conserving therapy (BCT). PATIENTS AND METHODS: Z11102 was a multicenter trial enrolling women with two or three separate sites of biopsy-proven malignancy separated by ≥ 2 cm within the same breast. Cosmetic outcome was a planned secondary endpoint. Data were collected with a four-point cosmesis survey (1 = excellent, 4 = poor) and the BREAST-Q (scored 0-100). All patients undergoing successful breast-conserving therapy were treated with whole-breast radiation. Associations were assessed with Chi square or Fisher's exact tests as appropriate. RESULTS: Cosmetic outcome data for 216 eligible women who completed therapy are included in this analysis. Of the 136 patients who completed the survey 2 years postoperatively, 70.6% (N = 96) felt the result was good or excellent, while 3.7% (N = 5) felt the result was poor. We found no significant differences in patient-reported cosmetic outcomes when stratifying by patient age, number of lesions (two or three), number of incisions, number of lumpectomies, or size of largest area of disease. Mean satisfaction score on the BREAST-Q was 77.2 at 6 months following whole-breast radiation and 73.7 at 3 years following surgery. CONCLUSIONS: BCT performed for MIBC results in good or excellent cosmesis for the majority of women. From a cosmetic perspective, BCT is a valid surgical approach to women with MIBC. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01556243.

The evolution of adjuvant radiation therapy for early-stage and locally advanced breast cancer.

Adjuvant radiation therapy is often delivered after breast cancer surgery, both in the post-lumpectomy and post-mastectomy settings. Standard fractionation whole breast irradiation (SF-WBI), which is typically delivered over 5-7 weeks, was previously considered the standard of care. More recent data has helped to establish hypofractionated whole breast irradiation (HF-WBI), which consists of a 3-4 week regimen, as a new standard of care. This article provides an overview of the major randomized trials that support the routine use of HF-WBI for the majority of patients undergoing breast-conserving surgery for early-stage breast cancer. Newer data on the use of a hypofractionated approach in the post-mastectomy setting, as well as ongoing randomized trials addressing this topic, are also discussed.

Individualized Prediction of Survival Benefit from Postmastectomy Radiotherapy for Patients with Breast Cancer with One to Three Positive Axillary Lymph Nodes.

PURPOSE: There still exist some arguments regarding the use of postmastectomy radiotherapy (PMRT) for patients with breast cancer carrying one to three positive axillary lymph nodes considering the heterogeneity of this cohort. Here, we developed a prognostic nomogram to estimate the probability of long-term outcome in patients receiving or not receiving PMRT in order to assist in making individually locoregional treatment decisions for this particular cohort. METHODS: Altogether, 20,336 women, aged 18 to 80 years, diagnosed with breast cancer, and carrying one to three positive nodes were identified in the Surveillance, Epidemiology, and End Results (SEER) database. We applied multivariant Cox hazard model to determine the impact of covariates on disease-specific survival (DSS) and overall survival (OS). Then, the nomogram was built accordingly. Internal and external validations were performed to examine the accuracy of nomograms. RESULTS: Age of diagnosis, tumor grade, size, estrogen and progesterone receptor status, and number of positive nodes were independent factors of DSS and OS in the multivariate analysis. Incorporating these factors into the constructed nomogram showed high accuracy when predicting 5- and 10-year survival, with internally and externally bootstrap-corrected concordance indexes in the range of 0.6 to 0.8. CONCLUSION: Besides the number of involved nodes, extra variables existed as predictors of survival outcomes in this cohort; therefore, the recommendation of PMRT or no PMRT requires comprehensive consideration. This clinically validated nomogram provided a useful tool that could aid decision making by estimating DSS and OS benefits from PMRT, useful in predicting 5- and 10-year DSS and OS for patients with one to three positive nodes after mastectomy. IMPLICATIONS FOR PRACTICE: This study evaluated population-based data to identify prognostic factors associated with patients with breast cancer with one to three lymph nodes and help clinicians to weigh the benefit of postmastectomy radiotherapy (PMRT). Surveillance, Epidemiology, and End Results (SEER) data were used to develop a prognostic nomogram to predict the likelihood of long-term survival with and without PMRT in order to optimize the individual locoregional control strategy for this particular cohort. This clinically validated nomogram provides a useful tool to predict 5- and 10-year disease-specific survival and overall survival for patients with one to three positive nodes and can aid tailored clinical decision making by estimating predicted benefit from PMRT.

The Feasibility of Breast-Conserving Surgery for Multiple Ipsilateral Breast Cancer: An Initial Report from ACOSOG Z11102 (Alliance) Trial.

BACKGROUND: Historically, multiple ipsilateral breast cancer (MIBC) has been a contraindication to breast-conserving therapy (BCT). We report the feasibility of BCT in MIBC from the ACOSOG Z11102 trial [Alliance], a single arm noninferiority trial of BCT for women with two or three sites of malignancy in the ipsilateral breast. METHODS: Women who enrolled preoperatively in ACOSOG Z11102 were evaluated for conversion to mastectomy and need for reoperation to obtain negative margins. Characteristics of women who successfully underwent BCT and those who converted to mastectomy were compared. Factors were examined for association with the need for margin reexcision. RESULTS: Of 198 patients enrolled preoperatively, 190 (96%) had 2 foci of disease. Median size of the largest tumor focus was 1.5 (range 0.1-7.0) cm; 49 patients (24.8%) had positive nodes. There were 14 women who underwent mastectomy due to positive margins, resulting in a conversion to mastectomy rate of 7.1% (95% confidence interval [CI] 3.9-10.6%). Of 184 patients who successfully completed BCT, 134 completed this in a single operation. Multivariable logistic regression analysis did not identify any factors significantly associated with conversion to mastectomy or need for margin reexcision. CONCLUSIONS: Breast conservation is feasible in MIBC with 67.6% of patients achieving a margin-negative excision in a single operation and 7.1% of patients requiring conversion to mastectomy due to positive margins. No characteristic was identified that significantly altered the risk of conversion to mastectomy or need for reexcision. CLINICALTRIALS. GOV IDENTIFIER: NCT01556243.

Roles of BCCIP deficiency in mammary tumorigenesis.

BACKGROUND: Dysregulated DNA repair and cell proliferation controls are essential driving forces in mammary tumorigenesis. BCCIP was originally identified as a BRCA2 and CDKN1A interacting protein that has been implicated in maintenance of genomic stability, cell cycle regulation, and microtubule dynamics. The aims of this study were to determine whether BCCIP deficiency contributes to mammary tumorigenesis, especially for a subset of breast cancers with 53BP1 abnormality, and to reveal the mechanistic implications of BCCIP in breast cancer interventions. METHODS: We analyzed the BCCIP protein level in 470 cases of human breast cancer to determine the associations between BCCIP and 53BP1, p53, and subtypes of breast cancer. We further constructed a unique BCCIP knockdown mouse model to determine whether a partial BCCIP deficiency leads to spontaneous breast cancer formation. RESULTS: We found that the BCCIP protein level is downregulated in 49% of triple-negative breast cancer and 25% of nontriple-negative breast cancer. The downregulation of BCCIP is mutually exclusive with p53 mutations but concurrent with 53BP1 loss in triple-negative breast cancer. In a K14-Cre-mediated conditional BCCIP knockdown mouse model, we found that BCCIP downregulation causes a formation of benign modules in the mammary glands, resembling the epidermal inclusion cyst of the breast. However, the majority of these benign lesions remain indolent, and only ~ 10% of them evolve into malignant tumors after a long latency. This tumor progression is associated with a loss of 53BP1 and p16 expression. BCCIP knockdown did not alter the latency of mammary tumor formation induced by conditional Trp53 deletion. CONCLUSIONS: Our data suggest a confounding role of BCCIP deficiency in modulating breast cancer development by enhancing tumor initiation but hindering progression. Furthermore, secondary genetic alternations may overcome the progression suppression imposed by BCCIP deficiency through a synthetic viability mechanism.

Short-term and long-term clinical outcomes of uncommon types of invasive breast cancer.

AIMS: Invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) are predominant and well-documented types of invasive breast cancer (IBC). We investigated the clinical outcomes of other types of IBC (i.e. uncommon IBC), which collectively account for Σ20% of all IBC cases, as these are largely unknown. METHODS AND RESULTS: We identified all IBC cases diagnosed in 2004-2006 (n = 159 293) and 2010-2011 (n = 118 822) from the Surveillance, Epidemiology and End Results (SEER) database. Uncommon IBCs included mixed IDC and ILC (MDLC), IDC mixed with other types of carcinoma, ILC mixed with other types of carcinoma, and other-type breast cancers (OCs). We estimated overall survival (OS) and cancer-specific survival in multivariate regression models. As compared with IDC, MDLC was associated with an increased OS [adjusted hazard ratio (aHR) = 0.92, P < 0.001 at Σ10 years of follow-up; aHR = 0.88, P = 0.01 at Σ4 years of follow-up], whereas OCs were associated with a decreased OS (aHR = 1.06, P = 0.005 at Σ10 years of follow-up; aHR = 1.23, P < 0.001 at Σ4 years of follow-up). Women with other uncommon IBCs had an OS similar to those with IDC. Heterogeneity in survival was observed for some subtypes of OC, with better OS for women with MDLC and tubular carcinoma. Radiotherapy extended OS for all types of IBC in older women (≥50 years). For younger women (<50 years), radiotherapy improved OS in women with IDC, but not in those with ILC or uncommon IBC. Radiotherapy did not change cancer-specific survival of younger women with any IBC. CONCLUSIONS: Uncommon IBCs have distinct patterns of prognosis and survival. The effectiveness of radiotherapy in women with uncommon IBC may differ by age. The underlying mechanisms warrant further studies.

Clinical characteristics and dose-volume histogram parameters associated with the development of pleural effusions in non-small cell lung cancer patients treated with chemoradiation therapy.

BACKGROUND: To investigate descriptive characteristics and dose metric (DM) parameters associated with development of pleural effusions (PlEf) in non-small cell lung cancer (NSCLC) treated with definitive chemoradiation therapy (CRT). MATERIALS AND METHODS: We retrospectively assessed treatment records and follow-up imaging of 66 NSCLC patients to identify PlEf formation after CRT. PlEf association between mean heart dose (MHD), mean lung dose (MLD), heart V5-V60 (HV), and lung V5-V60 (LV) were evaluated using Cox Proportional Hazard Models. RESULTS: A total of 52% (34 of 66 patients) of our population developed PlEf and the actuarial rates at 6 months, 12 months, and 18 months were 7%, 30%, and 42%, respectively. Median time to diagnosis was five months (range 0.06-27 months). The majority of PlEfs were grade one (67%) and developed at a median of four (0.06-13) months, followed by grade two (15%) at a median 11 (5-12) months, and grade three (18%) at a median of 11 (3-27) months. On multivariate analysis, increasing HV5-HV50, LV5-LV50, MHD, and MLD were associated with greater risk of PlEf. Higher grade PlEf was also associated with higher doses of radiation to the heart, while lung DM parameters were not significantly associated with higher PlEf grades. At five-months post-CRT, MHD of 25 Gy was associated with a 100% chance of grade one PlEf, an 82% risk of grade two PlEf, and a 19% risk of grade three PlEf. CONCLUSIONS: Post-CRT PlEf is common in NSCLC with the majority being grade one. Increasing heart and lung irradiation was associated with increased risk of PlEf. Increasing heart irradiation also correlated with development of increasing grades of PlEf. The impact of potential cardiopulmonary toxicity and resultant PlEfs after CRT requires additional study.