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Introduction: Prostate cancer remains the 3rd leading cause of cancer-related mortality in Canadian men, and yet screening for prostate cancer continues to be controversial because the majority of men diagnosed with prostate cancer do not die of the disease. It also remains uncertain whether treatment of cases that can be treated with curative intent alters the mortality rate. There are very few studies describing the presenting stage, risk groups, and survival after diagnosis for men dying of prostate cancer in the literature. In this study, we explored these characteristics for all men who died of prostate cancer in British Columbia between 2013 and 2015. Methods: The population-based BC Cancer databases were used to identify all patients diagnosed between January 2013 and December 2015 who died of prostate cancer. Patient, tumour, and treatment characteristics were collected, and the risk grouping for each tumour was determined. The proportion of cases in each risk group at the time of diagnosis was determined. Survival time from diagnosis to death was calculated for all patients and for each risk group using the Kaplan-Meier method. Results: A total of 1256 patients died of prostate cancer. Of patients who presented with metastatic disease, 57.2% presented with a Gleason score of 8 or more, compared with only 35.7% of patients who presented with nonmetastatic disease (p < 0.0001). The presenting stage and risk group of those dying of prostate cancer were as follows: 32% metastatic disease, 3% regional (defined as node-positive), 39% localized high risk, 9% localized intermediate risk, 4% localized low risk, 6% localized not otherwise specified, and 7% unknown. Therefore, 80.3% of those with a known risk group presented with either localized high-risk, regional, or metastatic disease at diagnosis. The median survival times from diagnosis to death were 12 years for localized low-risk, 10 years for localized intermediate-risk, 6.5 years for localized high-risk, 4 years for regional, and 1.7 years for metastatic disease at diagnosis. Conclusions: This population-based analysis demonstrates that patients with localized high-risk, regional, or metastatic disease at diagnosis constitute the overwhelming majority of patients who die of prostate cancer in British Columbia. Unless these disease states can reliably be identified at an earlier low- or intermediate-risk localized state in the future, it is unlikely that treatment of localized low- and intermediate-risk cancer will have an impact on survival. Furthermore, patients with de novo metastatic disease had identifiable risk factors of a higher prostate-specific antigen and Gleason score. Further studies are required to confirm these results. [ABSTRACT FROM AUTHOR]

Background The Spinal Instability Neoplastic Score (sins) was developed to identify patients with spinal metastases who may benefit from surgical consultation. We aimed to assess the distribution of sins in a population-based cohort of patients undergoing palliative spine radiotherapy (rt) and referral rates to spinal surgery pre-rt. Secondary outcomes included referral to a spine surgeon post-rt, overall survival, maintenance of ambulation, need for re-intervention, and presence of spinal adverse events. Methods We retrospectively reviewed ct simulation scans and charts of consecutive patients receiving palliative spine rt between 2012 and 2013. Data were analyzed using Student's t-test, Chi-squared, Fisher's exact, and Kaplan- Meier log-rank tests. Patients were stratified into low (<7) and high (≥7) sins groups. Results We included 195 patients with a follow-up of 6.1 months. The median sins was 7. The score was 0 to 6 (low, no referral recommended), 7 to 12 (intermediate, consider referral), and 13 to 18 (high, referral suggested) in 34%, 59%, and 7% of patients, respectively. Eleven patients had pre-rt referral to spine surgery, with a surgery performed in 0 of 1 patient with sins 0 to 6, 1 of 7 with sins 7 to 12, and 1 of 3 with sins 13 to 18. Seven patients were referred to a surgeon post-rt with salvage surgery performed in two of those patients. Primary and secondary outcomes did not differ between low and high sins groups. Conclusion Higher sins was associated with pre-rt referral to a spine surgeon, but most patients with high sins were not referred. Higher sins was not associated with shorter survival or worse outcome following rt. [ABSTRACT FROM AUTHOR]

Background The use of neoadjuvant systemic therapy (NAST) in the treatment of breast cancer is increasing, and the role of adjuvant radiation therapy (RT) in that setting is uncertain. We sought to review and report the use of NAST, its trends over time, and its relationship with the prescribing patterns of locoregional RT in a provincial cancer system. Methods Patients with stages I-III breast cancer diagnosed during 2007-2012 were identified using a provincial database. Patient, tumour, and treatment characteristics were extracted. Multivariable logistic regression analyses were used to assess associations with the use of NAST. Kaplan-Meier and Cox regression were used for survival analyses. Results Of the 11,658 patients who met the inclusion criteria, 602 (5%) had received NAST. Use of NAST was more frequent in stage III patients (53%) than in stages I and II patients (2%). In clinically lymph-node positive patients, a pathology assessment was made approximately 50% of the time. Higher clinical tumour stage and increasing clinical nodal stage predicted for increasing use of NAST and of nodal RT after NAST, but pathologic nodal status after NAST was not associated with use of nodal RT. A statistically significant survival difference was observed between patients in the NAST and no- NAST groups, but that significance disappeared in a multivariable Cox regression analysis. Conclusions This population-based study demonstrated 5% use of NAST for breast cancer. Most patients received nodal RT after NAST, and nodal RT was not associated with pathologic stage after NAST. Findings likely reflect the realities of clinical practice and show that reliance on clinical nodal staging results in outcomes similar to those reported in the literature. [ABSTRACT FROM AUTHOR]

Background Proliferative scoring of breast tumours can guide treatment recommendations, particularly for estrogen receptor (er)-positive, her2-negative, T1-2, N0 disease. Our objectives were to estimate the proportion of such patients for whom proliferative indices [mitotic count (mc), Ki-67 immunostain, and Oncotype dx (Genomic Health, Redwood City, CA, U.S.A.) recurrence score (rs)] were obtained. compare the indices preferred by oncologists with the indices available to them. correlate Nottingham grade (ng) and its subcomponents with Oncotype dx. assess interobserver variation. Methods All of the er-positive, her2-negative, T1-2, N0 breast cancers diagnosed from 2007 to 2011 (n = 5110) were linked to a dataset of all provincial breast cancers with a rs. A 5% random sample of the 5110 cancers was reviewed to estimate the proportion that had a mc, Ki-67 index, and rs. Correlation coefficients were calculated for the rs with ng subcomponent scores. Interobserver variation in histologic grading between outside and central review pathology reports was assessed using a weighted kappa test. Results During 2007-2011, most cancers were histologically graded and assigned a mc; few had a Ki-67 index or rs. The ng and mc were significantly positively correlated with rs. The level of agreement in histologic scoring between outside and central pathology reports was good or very good. Very few cases with a low mc had a high rs (1.8%). Conclusions Patients with low ng and mc scores are unlikely to have a high rs, and thus are less likely to benefit from chemotherapy. In the context of limited resources, that finding can guide clinicians about when a rs adds the most value. [ABSTRACT FROM AUTHOR]

Multiple randomized trials have demonstrated that breast-conserving therapy with partial mastectomy and radiotherapy provides survival equivalent to that seen with mastectomy for patients with early-stage breast cancer. Breast-conserving therapy has been associated with better quality of life relative to mastectomy and has become the standard of care for patients with early-stage breast cancer. Young age has been identified as a risk factor for recurrence and death from breast cancer. Some studies have suggested that young women (less than 35 or 40 years of age) have inferior outcomes with breast-conserving therapy, implying that such women may be better served by mastectomy. On review of the available literature, there is no definitive evidence that mastectomy provides a consistent, unequivocal recurrence-free or overall survival benefit over breast-conserving therapy. However, available meta-analyses have not compared outcomes in young women specifically, and such analyses should be performed. In the interim, breast-conserving therapy is not contraindicated in young women (less than 40 years of age) and can be used cautiously; however, such women should be advised of the lack of unequivocal data proving that survival is equivalent to that with mastectomy in their age group. [ABSTRACT FROM AUTHOR]

Purpose: The Mini Mental State Examination (MMSE) is the most commonly chosen cognitive screening test (CST) in clinical practice and trials, despite its poor sensitivity, likely because of its prognostic utility. The Montreal Cognitive Assessment (MoCA) is an alternative CST, is more sensitive, and is better correlated with quality of life.Methods: Sixty-five patients with brain metastases were prospectively accrued and completed both the MMSE and MoCA. We compared the prognostic utility of both CSTs.Results: The mean age of patients was 59.0 years; 42.0% had single brain metastases. Median MMSE and MoCA scores were 28 and 22, respectively. Median overall survival (OS) was worse for individuals with below- versus above-average MMSE scores (10.4 versus 36.3 weeks, p = 0.007). Likewise, below- versus above-average MoCA scores were prognostic (6.3 versus 50.0 weeks, p < 0.001). Median OS for MoCA scores <22, 22-26, and >26 were 6.3, 30.9, and 61.7 weeks, respectively (p < 0.001). On multivariable analysis, below-average MMSE scores were no longer prognostic (hazard ratio [HR] = 1.71 [0.90-3.26]), though below-average MoCA scores were (HR = 5.44 [2.70-10.94]). Furthermore, the MoCA demonstrated superior prognostic utility when comparing multivariable models with continuous CST scores.Conclusions: Our results indicate that the MoCA is a superior prognostic indicator than the MMSE. Furthermore, given its superior sensitivity and better correlation with quality of life, the MoCA should be preferentially chosen in clinical practice and trials. [ABSTRACT FROM AUTHOR]

We consider an ambulatory care unit (ACU) in a large cancer centre, where operational and resource utilization challenges led to overcrowding, excessive delays, and concerns regarding safety of critical patient care duties. We use simulation to analyze the simultaneous impact of operations, scheduling, and resource allocation on patient wait time, clinic overtime, and resource utilization. The impact of these factors has been studied before, but usually in isolation. Further, our model considers multiple clinics operating concurrently, and includes the extra burden of training residents and medical students during patient consults. Through scenario analyses we found that the best outcomes were obtained when not one but multiple changes were implemented simultaneously. We developed configurations that achieve a reduction of up to 70% in patient wait times and 25% in physical space requirements, with the same appointment volume. The key findings of the study are the importance of on time clinic start, the need for improved patient scheduling; and the potential improvements from allocating examination rooms flexibly and dynamically among individual clinics within each of the oncology programs. These findings are currently being evaluated for implementation by senior management. [ABSTRACT FROM AUTHOR]

We compared the long-term impact of 1- and 2-year screening mammography intervals using prognostic, screening, and outcome information for women aged 50-74 years obtained from the Screening Mammography Program of British Columbia in two time periods, prior to 1997 (policy of annual mammography) and after 1997 (biennial mammography). Survival was estimated for both periods using a prognostic model and the expected rate of interval and screen-detected cancers. The likelihood of a screen-detected cancer with annual screening was 2.32 per thousand screens and with biennial screening was 3.32 per thousand screens. The prognostic profile of screen-detected cancers was better than that of interval cancers. Among both screen-detected and interval cancers, the prognostic profiles with annual and biennial screening were similar. The estimated breast cancer-specific survival rates for women undergoing annual and biennial screening mammography were 95.2 and 94.6% at 5 years, and 90.4 and 89.2% at 10 years, respectively. Annual compared to biennial mammography was associated with a 1.2% increase in the estimated 10-year breast cancer-specific survival for women aged 50-74 years, diagnosed with invasive breast cancer after screening programme attendance. [ABSTRACT FROM AUTHOR]

BACKGROUND: We have previously used an evidence-based, epidemiologic approach to estimate the proportion of incident cases that should be treated with radiotherapy (RT) for lung cancer. The first objective of the present study was to compare this evidence-based estimate of the appropriate rate of use of RT with the rates observed in selected 'benchmark' communities where there are no barriers to the appropriate use of RT and no incentives to the unnecessary use of RT. The second objective of the study was to compare the rates of use of RT in the general populations in the United States and Canada with the estimated appropriate rate. METHODS: We established benchmark rates for the use of RT for lung cancer in Ontario, Canada, where: 1) residents make no direct payments for RT; 2) all RT is provided by site-specialized radiation oncologists in multidisciplinary cancer centers, and 3) radiation oncologists receive a salary in lieu of technical fees. Communities located close to cancer centers without long waiting lists for RT were selected to serve as benchmarks. Prospectively gathered electronic treatment records from all RT cancer centers were linked to the provincial cancer registry to describe the rate of use of RT in Ontario. The public use file of Surveillance, Epidemiology and End Results Registries (SEER) was used to describe the use of RT in the United States. RESULTS: Overall, 41.3% (95% confidence interval [CI], 39.9%, 42.7%) of incident cases of lung cancer received RT as part of their initial management in the benchmark communities compared with the evidence-based estimate of 41.6% (95% CI, 39.2%, 44.1%). The rate of use of RT in the initial management of nonsmall cell lung cancer (NSCLC) in the benchmark communities was 49.3% (95% CI, 47.5%, 51.1%) compared with the evidence-based estimate of 45.9% (95% CI, 41.6%, 50.2%). The use of RT in the initial management of small-cell lung cancer (SCLC) in the benchmark communities was 47.0% (95% CI, 43.3%, 50.7%) compared with the evidence-based estimate of 45.4% (95% CI, 42.4%, 48.4%). In many counties of Ontario, the observed rates of RT use in the initial management of lung cancer were significantly lower than either the benchmark rate or the evidence-based estimate of the appropriate rate. In contrast, rates of use of RT in most counties in the SEER regions of the United States were close to, or higher than, the estimated appropriate rate. CONCLUSIONS: The observed benchmark rate converged on the evidence-based estimate of the appropriate rate of use of RT for lung cancer, suggesting that either measure might reasonably be used as a 'standard' against which to compare rates observed in similar populations elsewhere. [ABSTRACT FROM AUTHOR]

Abstract Purpose To evaluate the survival of patients with human epidermal growth factor receptor 2 (HER2) positive and negative metastatic breast cancer irradiated for brain metastases before and after the availability of trastuzumab (T). Materials and methods Women diagnosed with brain metastasis from breast cancer in two eras between 2000 and 2007 (T-era, n = 441) and 1986 to 1992 (PreT-era, n = 307), treated with whole brain radiotherapy (RT) were identified. In the T-era, HER2 testing was part of routine clinical practice, and in the preT-era 128/307 (42%) cases had HER2 testing performed retrospectively on tissue microarrays. Overall survival (OS) was estimated using the Kaplan-Meier method and comparisons between eras used log-rank tests. Results In the preT- and T-era cohorts, the rate of HER2 positivity was 40% (176/441) and 26% (33/128) (p Conclusions Distinct from patients with HER2 negative disease in whom no difference in survival after brain RT was observed over time, patients with HER2 positive brain metastases experienced significantly improved survival subsequent to the availability of trastuzumab.

Abstract Background The primary objective of this research was to assess the relationship between FPs’ knowledge of palliative radiotherapy (RT) and referral for palliative RT. Methods 1001 surveys were sent to FPs who work in urban, suburban, and rural practices. Respondents were tested on their knowledge of palliative radiotherapy effectiveness and asked to report their self-assessed knowledge. Results The response rate was 33%. FPs mean score testing their knowledge of palliative radiotherapy effectiveness was 68% (SD = 26%). The majority of FPs correctly identified that painful bone metastases (91%), airway obstruction (77%), painful local disease (85%), brain metastases (76%) and spinal cord compression (79%) can be effectively treated with RT, though few were aware that hemoptysis (42%) and hematuria (31%) can be effectively treated. There was a linear relationship between increasing involvement in palliative care and both self-assessed (p Conclusions Self-assessed and tested knowledge of palliative RT is positively associated with referral for palliative RT. Since palliative RT is underutilized, further research is needed to assess whether family physician educational interventions improve palliative RT referrals. The current study suggests that studies could target family physicians already in practice, with educational interventions focusing on hemostatic and other less commonly known indications for palliative RT.

Abstract Background The timely and appropriate adoption of new radiation therapy (RT) technologies is a challenge both in terms of providing of optimal patient care and managing health care resources. Relatively little is known regarding the rate at which new RT technologies are adopted in different jurisdictions, and the barriers to implementation of these technologies. Methods Surveys were sent to all radiation oncology department heads in Canada regarding the availability of RT equipment from 2006 to 2010. Data were collected concerning the availability and use of Intensity Modulated Radiation Therapy (IMRT) and stereotactic radiosurgery (SRS), and the obstacles to implementation of these technologies. Results IMRT was available in 37% of responding centers in 2006, increasing to 87% in 2010. In 2010, 72% of centers reported that IMRT was available for all patients who might benefit, and 37% indicated that they used IMRT for "virtually all" head and neck patients. SRS availability increased from 26% in 2006 to 42.5% in 2010. Eighty-two percent of centers reported that patients had access to SRS either directly or by referral. The main barriers for IMRT implementation included the need to train or hire treatment planning staff, whereas barriers to SRS implementation mostly included the need to purchase and/or upgrade existing planning software and equipment. Conclusions The survey showed a growing adoption of IMRT and SRS in Canada, although the latter was available in less than half of responding centers. Barriers to implementation differed for IMRT compared to SRS. Enhancing human resources is an important consideration in the implementation of new RT technologies, due to the multidisciplinary nature of the planning and treatment process.

Abstract Purpose This study examined the population-based use and outcomes of brain radiotherapy (BRT) for brain metastases (BM) from breast cancer with a focus on repeat BRT in the trastuzumab era. Methods and materials All women with breast cancer diagnosed from 2000-2007 and treated with BRT were retrospectively identified from a provincial database. Results A total of 441 women with BM from breast cancer were identified. The median age was 55 years and 40% (176/441) had human epidermal growth factor receptor 2 (HER2) positive disease. The median survival (MS) from the initial BRT for all 441 women was 4.5 months. The MS by Radiation Therapy Oncology Group Recursive Partitioning Analysis (RPA) class was: 1 (14.5 months), 2 (6.4 months) and 3 (1.8 months). For the 37 cases receiving repeat BRT, 27% (10/37) had stereotactic radiosurgery (SRS) and 70% (26/37) had HER2 positive disease, of which, 81% (21/26) received trastuzumab in the metastatic setting. For repeat BRT, the median survival by RPA class was: 1 (9.8 months), 2 (7.4 months) and 3 (2.0 months). For RPA class 1 and 2, the one-year overall survival (OS) was 45%. Conclusion The proportion of cases with HER2 positive disease was increased at repeat BRT compared to initial BRT. RPA class 1 and 2 patients should be considered for repeat BRT.

While estimation of prognosis for patients with oligometastatic cancer is important to aid in treatment decision making, at present, prognostication tools are lacking. The purpose of this study was to develop predictive models for polymetastatic progression free survival (PPFS) and overall survival (OS), based on patient outcomes on the SABR-5 clinical trial. In the SABR-5 trial (a multi-center, single arm, phase II clinical trial), 381 patients with 1-5 oligometastases or oligoprogressing lesions were treated with stereotactic ablative radiotherapy (SABR). Prostate cancer was the most common histology (32%), followed by colorectal (16%), breast (11%), lung (9%), and renal (9%). Most patients (91%) were treated for 1-2 metastases. PPFS was defined as time from SABR until polymetastatic failure (≥ 6 metastases, or malignant pleural effusion/malignant ascites) or death. We trained separate Cox models for PPFS and OS. An elastic net penalty was used to select from candidate covariates. The model was internally validated using 10-fold cross validation with three repetitions and evaluated using partial likelihood. The proportional hazards and linearity assumptions were tested by examination of scaled Schoenfold Residuals and Martingale Residuals, respectively. After a median follow-up time of 28.0 months (interquartile range [IQR]19.1 – 39.1), median PPFS was 34.3 months (95% confidence interval [CI] 28.8 – 39.9), and median OS was 50.5 months (95% CI 45.2 – 58.9). The resulting PPFS model contained four covariates: primary tumor type (prostate, colorectal, lung, breast, renal, other), ECOG (1-2 vs 0), oligoprogression (yes vs no), number of organs with metastases (single vs multiple). The cross-validated C-Index was 0.66 [95% CI 0.64 – 0.68]. The OS model had five covariates: age (continuous), primary tumor type (prostate, colorectal, lung, breast, renal, other), ECOG (1-2 vs 0), number of organs with metastases (single vs multiple), presence of brain metastasis (yes vs no) and had a corresponding C-Index of 0.67 [95% CI 0.64 – 0.700]. These nomograms can be a useful guiding tool for clinicians in predicting PPFS and OS in patients treated with SABR in oligometastatic or oligoprogressive setting. These models should be externally validated. [ABSTRACT FROM AUTHOR]

Despite advancements in stereotactic ablative radiotherapy (SABR) for non-spine bone metastases (NSBMs), uncertainty remains surrounding target volumes. While expert consensus guidelines recommend a clinical target volume (CTV), patterns of failure analyses are lacking, and larger treatment volumes may be associated with higher toxicity. This study aims to compare local failure, marginal failure, and toxicity in NSBMs treated with versus without a CTV in a population-based cohort. A retrospective review was conducted on all patients in British Columbia treated with SABR for NSBMs on the single-arm phase II SABR-5 trial (November 2016 – July 2020) and on the BC Oligometastases Registry (August 2020 - October 2022). Use of a CTV was optional for both SABR-5 and the Registry. NSBMs were stratified based on CTV use for treatment planning. A total of 158 patients (113 on SABR-5 and 45 on Registry) with 200 NSBMs were included. One hundred fifty-nine (80%) NSBMs were treated with a CTV and 41 (21%) without a CTV. The most common histologies were prostate (60%), breast (17%) and lung cancer (6%), and lesions received 35 Gy in 5 fractions (81%) or 24 Gy in 2 fractions (14%). Rib (34%) and pelvis (47%) were the most common lesion sites. Groups with vs without a CTV did not differ in baseline patient or tumor characteristics. After a median follow-up time of 33.7 months (interquartile range [IQR] = 19.5-48.9), local failure rates did not differ, with 2-year local failure 9.3% (95% confidence interval [CI] = 4.4 – 14.2) in lesions treated with a CTV and 7.6% (95% CI = 0 – 15.8) without a CTV (P = 0.39). Marginal failure, defined as disease recurrence outside of the GTV but within 1 cm of the PTV, occurred in 15 (8%) of lesions and 2-year cumulative incidence did not differ between groups (6.2% [95% CI = 2.3 – 10.1] and 2.6%, [95% CI = 0 – 7.5], respectively [ P = 0.16]). Overall survival (OS) was also similar (2-year OS = 84.6%, 95% CI = 78.1 – 91.1, and 90.3%, 95% CI = 79.9 – 100, respectively; P = 0.64). The most common grade ≥ 2 toxicities were pain (n = 18, 9%) and fracture (n = 8, 4%). There were no grade 4 or 5 toxicities. The 2-year cumulative incidence of grade ≥ 2 toxicity did not differ between groups (14.9%, 95% CI = 3.9-25.9 and 15.6%, 95% CI = 9.9-21.3, respectively; P = 0.78). Due to low number of events, local and marginal failure events were collated for a multivariable regression analysis. On multivariable regression, use of a CTV was not associated with the risk of local-marginal failure (hazard ratio [HR] = 2.41, 95% CI = 0.81 – 7.18, P = 0.11). Extraosseous extension (HR = 2.62, 95% CI = 1.07-6.38, P = 0.035) and lack of receipt of systemic therapy (HR = 3.03, 95% CI = 1.40-6.67, P = 0.005) were associated with higher risk. Use of a CTV was not associated with local or marginal failure or toxicity. Extraosseous extension and lack of receipt of systemic therapy were associated with higher risk of local-marginal failure. This may assist in informing future approaches to treatment planning in this patient population. [ABSTRACT FROM AUTHOR]

Purpose: The recently developed European Society for Radiotherapy and Oncology (ESTRO)/European Organization for Research and Treatment of Cancer (EORTC) oligometastatic disease (OMD) classification has not been validated in terms of its prognostic significance. This study stratified patients from the phase II SABR-5 trial based on ESTRO/EORTC criteria and compared progression-free survival (PFS) and overall survival (OS) to determine the prognostic significance of the classification scheme.Methods and Materials: The SABR-5 trial was a single arm phase II study conducted at the 6 regional cancer centers across British Columbia (BC), Canada, where SABR for oligometastases was only offered on trial. Patients with up to 5 oligometastases (total or not controlled by prior treatment and including induced OMD) underwent SABR to all lesions. Patients were 18 years of age or older, Eastern Cooperative Oncology Group 0 to 2, and life expectancy ≥6 months. PFS and OS were calculated using the Kaplan-Meier method and differences between OMD groups were assessed with log-rank tests. Univariable and multivariable analyses were performed using Cox regression modeling.Results: Between November 2016 and July 2020, 381 patients underwent SABR on trial. Median follow-up was 27 months (interquartile range, 18-36). The most frequent OMD group was de novo OMD (69%), followed by repeat (16%) and induced (13%). OMD groups differed significantly in PFS (P < .001) but not OS (P = .069). The OMD classification was an independent predictor of both PFS (P = .005) and OS (P = .002). Of the 5 classification factors, only chronicity (synchronous, hazard ratio, 0.52; P = .027) and oligoprogression (hazard ratio, 2.05; P = .004) were independently prognostic for OS.Conclusions: In this large prospective cohort, the ESTRO/EORTC classification was an independent predictor of PFS and OS and should be used to identify specific patient groups for clinical trials. In this trial population, the prognostic power is largely attributable to chronicity and oligoprogression. Simplification of the framework may be possible in the future and allow for greater ease of use; however, further data on underrepresented OMD groups and histologies will be required. [ABSTRACT FROM AUTHOR]

While SABR is known for its overall low toxicity and safety, there remains a research gap regarding its combined use with specific systemic therapies. This study aims to evaluate the toxicity of SABR in combination with various systemic therapies. The hypothesis is that certain systemic therapies would significantly increase the risk of Grade 2+ and Grade 3+ radiation therapy-related toxicities when used concurrently with Stereotactic Ablative Radiotherapy (SABR). A secondary analysis of the SABR-5 trial compared grade 2+ and 3+ toxicities associated with SABR until the last follow-up in patients receiving high-risk or non-high-risk systemic therapy at intervals of 3 months, 2 weeks, 1 week, and concurrently with SABR. High-risk systemic therapy was a priori defined, based on previous literature, as drugs that, when given close to SABR, may increase treatment toxicity. This category encompasses cytotoxic chemotherapy drugs, multi-targeted tyrosine kinase inhibitors, cyclin-dependent kinase 4/6 inhibitors, epidermal growth factor receptor inhibitors, anti-vascular endothelial growth factor agents, and anti-cytotoxic T-lymphocyte-associated protein 4 agents. Among the 381 patients, the actuarial rates of grade 2+ and 3+ toxic effects were as follows: for patients not on systemic therapy 3 months prior to SABR (n = 202), the rates were 17.3% and 3.5%, respectively; for patients on non-high-risk systemic therapy concurrent with SABR (n = 102), the rates were 18.6% and 3.9%, respectively; and for patients on high-risk systemic therapy concurrent with SABR (n = 5), the rates were notably higher at 60% and 40%, respectively. On multivariable analysis, concurrent use of high-risk systemic therapy was associated with a higher risk of grade 2+ (OR = 7.15, P = 0.043) or 3+ toxic effects (OR = 13.9, P = 0.015). Significance was not observed when high-risk drugs were used only within 1 week, 2 weeks, or 3 months of SABR, nor with the use of any non-high-risk drugs. A second adverse factor included increased tumor diameter (per 1 cm increment; G2+ OR = 1.25, P < 0.001; G3+ OR = 1.27, P = 0.015). High-risk drugs have demonstrated a potential of increased SABR-related toxicity, warranting caution in their concurrent use with SABR. In contrast, the combination of non-high-risk drugs with SABR may be safe. Ongoing efforts are essential to identify potential risks and uncertainties associated with this therapeutic combination. [ABSTRACT FROM AUTHOR]