Non-Melanoma Skin Cancers in the Older Patient.

PURPOSE OF REVIEW: The incidence of non-melanomatous skin cancer (NMSC) increases with age and there are specific considerations regarding management of NMSC for the older patient population. Here we will review current data regarding treatment considerations and options for older patients with NMSC. RECENT FINDINGS: Hypofractionated regimens and high-dose brachytherapy may be non-surgical treatment options for older patients with NMSC. Other less aggressive strategies such as active surveillance can also be considered in some settings. Management of NMSC in the older patient population requires a thorough assessment of comorbidities, frailty, and life expectancy. Additionally, discussions regarding goals of care and quality of life (QOL) issues are especially important in this population. Older patients with NMSC in particular may benefit from a tailored treatment plan based on current available data rather than a broad application of general treatment guidelines for NMSC.

Multiple colony antifungal susceptibility testing detects polyresistance in clinical Candida cultures: a European Confederation of Medical Mycology excellence centers study.

OBJECTIVES: Many factors influence the outcome of in vitro antifungal susceptibility testing (AFST), including endpoint definition, inoculum sizes, time and temperature of incubation, and growth medium used. This European Confederation of Medical Mycology (ECMM) Excellence center driven study investigated multiple colony testing (MCT) of five separate colonies to investigate the prevalence of polyresistance (PR), defined as heterogeneous MICs from a same-species Candida culture irrespective of the underlying resistance mechanism. METHODS: Candida spp. MCT for fluconazole and anidulafungin was performed by Etest prospectively comprising 405 clinical samples. MCT results were compared to the real-life routine MIC data and PR was assessed. Candida colonies displaying strong PR were selected for genotyping using multilocus sequence typing and random amplified polymorphic DNA assays for C. lusitaniae. RESULTS: Candida PR was observed in 33 of 405 samples (8.1%), with higher rates for non-albicans species (26/186, 14%) than for C. albicans (7/219, 3.2%), and for fluconazole than for anidulafungin. MCT detected acquired resistance more often than routine AFST (18/405, 4.5%) and 9 of the 161 investigated blood cultures showed PR (5.6%). Multilocus sequence typing and random amplified polymorphic DNA did not reveal a uniform genetic correlate in strains studied. CONCLUSIONS: This study shows that Candida single MIC-values obtained in routine diagnostics may be incidental, as they fail to detect PR and resistant subpopulations reliably. The reasons for PR seem to be manifold and should be regarded as a phenotypical expression of genomic variability irrespective of the underlying resistance mechanism, which may help to interpret ambiguous and non-reproducible AFST results.

#ThisIsBrachytherapy: Increasing awareness of brachytherapy.

PURPOSE: The use of brachytherapy continues to be a vital application of radiation oncology for various cancers. Despite this, there has been a decrease in the utilization of brachytherapy in many cancers. Social media in medicine facilitates engagement and advocacy. We launched a social media campaign to bring awareness of brachytherapy throughout the world with #ThisIsBrachytherapy hashtag on July 17, 2019. METHODS AND MATERIALS: #ThisIsBrachytherapy hashtag was registered with Symplur Healthcare Hashtag Project. We collected total tweet counts, retweet counts, impression counts, geolocation, top 10 influencers, associated hashtags, associated words, and word sentiment score. RESULTS: The campaign launched on July 17, 2019, had a total of 145 tweets on that day with 213,416 impressions. Twenty-seven accounts (45%) were identified as physicians. Top countries which tweeted, among those with information available, included the United States, United Kingdom, and Australia. Since July 17, 2019, there has been an increase in tweets using #ThisIsBrachytherapy, with 1990 total tweets with 1,999,248 impressions. Fifty-four percent (1030) of the tweets contained photos and 319 contained links. This was from 462 unique users. Word sentiment was overwhelmingly positive. Associated hashtags with #ThisIsBrachytherapy included most commonly #radonc, #brachytherapy, #brachy, #prostatecancer, and #pcsm. CONCLUSIONS: The #ThisIsBrachytherapy inaugural campaign was successful and has continued to grow throughout the months after the initiation. By continuing to advocate for brachytherapy through the social media campaign #ThisIsBrachytherapy, we can empower radiation oncologists, especially trainees, and patients to address underutilization.

Evaluating Bias in Speaker Introductions at the American Society for Radiation Oncology Annual Meeting.

PURPOSE: Introducing a physician without a professional title may reinforce bias in medicine by influencing perceived credibility. We evaluated differences in the use of professional titles in introductions of speakers at recent American Society for Radiation Oncology (ASTRO) Annual Meetings. METHODS AND MATERIALS: We reviewed recordings from the 2017 to 2019 ASTRO Annual Meetings and included complete introductions of speakers with a doctoral degree. Professional introduction was defined as "Doctor" or "Professor" followed by the speaker's full or last name. We collected use of professional introduction, introducer gender, speaker gender, and speaker professional and demographic variables. Identified speakers were sent surveys to collect self-reported demographic data. Analysis was performed using χ2 tests and multivariable logistic regression (MVA). RESULTS: Of 3267 presentations reviewed, 1226 (38%) met the inclusion criteria. Overall, 805 (66%) speakers and 710 (58%) introducers were men. Professional introductions were used in 74% (2017), 71% (2018), and 69% (2019) of the presentations. There was no difference in the use of professional introductions for male and female speakers (71% vs 73%; P = .550). On MVA, male introducers were associated with decreased use of professional address (odds ratio [OR], 0.36; 95% confidence interval [CI], 0.26-0.49; P < .001). At the 2019 conference, professional introduction was less likely to be used (2019 vs 2017: OR, 0.68; 95% CI, 0.49-0.96; P = 0.026). Those who self-identified as Asian/Pacific Islander were twice as likely to receive a professional introduction compared with those who identified as white (OR, 1.95; 95% CI, 1.07-3.64; P = .033). CONCLUSION: Male introducers were significantly less likely to introduce any speaker, regardless of gender, by their professional title, and overall use of professional introductions decreased from 2017 to 2019. Furthermore, no difference in professional introduction use by speaker gender was identified at the recent ASTRO meetings. Implementing speaker guidelines could increase the use of professional introductions and raise awareness of unconscious bias at future ASTRO meetings.

Current Social Media Use Among Radiation Oncology Trainees.

PURPOSE: Resident physicians use social media (SM) for many reasons. We sought to characterize current SM use by radiation oncology (RO) trainees for education and professional development. METHODS AND MATERIALS: An anonymous 40-question survey was sent by e-mail to RO residents in the 2018 to 2019 academic year. SM platform use, time spent on SM, professional use, and opinions regarding SM use were assessed. Descriptive statistics and a univariate logistic regression analysis were performed to identify factors associated with perceptions of SM and spending >25% of SM time for academic or professional purposes. RESULTS: Of the 615 residents surveyed, 149 responded (24% response rate). Facebook (73%), theMednet (62%), Instagram (59%), Twitter (57%), and Doximity (50%) were the top SM platforms used. Most respondents (53%) reported <25% of overall SM time on professional/academic purposes, and 21% reported using SM >60 minutes per day over the past week. Residents with an RO mentor on SM (n = 35; 24%; odds ratio [OR]: 2.79; 95% confidence interval [CI], 1.29-6.08; P = .010), those participating in RO discussions on SM (n = 71; 48%; OR: 2.85; 95% CI, 1.42-5.72; P = .003), and those interacting with professional societies (n = 69; 46%; OR: 7.11; 95% CI, 3.32-15.24; P < .001) were more likely to spend >25% of their SM time on professional/academic purposes. The vast majority of respondents agreed that SM exposed them to novel educational content (82%) and was helpful for career development (65%). In addition, 69% agreed that SM can improve clinical skills and knowledge. A substantial minority agreed that SM distracts them from studying (38%) or they felt pressure to have a SM presence (29%). CONCLUSIONS: Most RO residents reported that SM provides novel educational content and can help with career development. Potential disadvantages of SM for trainees may include distraction and pressure to maintain a SM presence. SM use by RO trainees merits further research to optimize its potential for education and professional development.

Culture-Free Detection of Antibiotic Resistance Markers from Native Patient Samples by Hybridization Capture Sequencing.

The increasing incidence of antimicrobial resistance (AMR) is a major global challenge. Routine techniques for molecular AMR marker detection are largely based on low-plex PCR and detect dozens to hundreds of AMR markers. To allow for comprehensive and sensitive profiling of AMR markers, we developed a capture-based next generation sequencing (NGS) workflow featuring a novel AMR marker panel based on the curated AMR database ARESdb. Our primary objective was to compare the sensitivity of target enrichment-based AMR marker detection to metagenomics sequencing. Therefore, we determined the limit of detection (LOD) in synovial fluid and urine samples across four key pathogens. We further demonstrated proof-of-concept for AMR marker profiling from septic samples using a selection of urine samples with confirmed monoinfection. The results showed that the capture-based workflow is more sensitive and requires lower sequencing depth compared with metagenomics sequencing, allowing for comprehensive AMR marker detection with an LOD of 1000 CFU/mL. Combining the ARESdb AMR panel with 16S rRNA gene sequencing allowed for the culture-free detection of bacterial taxa and AMR markers directly from septic patient samples at an average sensitivity of 99%. Summarizing, the newly developed ARESdb AMR panel may serve as a valuable tool for comprehensive and sensitive AMR marker detection.

Genomic and Phenotypic Analysis of Linezolid-Resistant Staphylococcus epidermidis in a Tertiary Hospital in Innsbruck, Austria.

Whole genome sequencing is a useful tool to monitor the spread of resistance mechanisms in bacteria. In this retrospective study, we investigated genetic resistance mechanisms, sequence types (ST) and respective phenotypes of linezolid-resistant Staphylococcus epidermidis (LRSE, n = 129) recovered from a cohort of patients receiving or not receiving linezolid within a tertiary hospital in Innsbruck, Austria. Hereby, the point mutation G2603U in the 23S rRNA (n = 91) was the major resistance mechanism followed by the presence of plasmid-derived cfr (n = 30). The majority of LRSE isolates were ST2 strains, followed by ST5. LRSE isolates expressed a high resistance level to linezolid with a minimal inhibitory concentration of ≥256 mg/L (n = 83) in most isolates, particularly in strains carrying the cfr gene (p < 0.001). Linezolid usage was the most prominent (but not the only) trigger for the development of linezolid resistance. However, administration of linezolid was not associated with a specific resistance mechanism. Restriction of linezolid usage and the monitoring of plasmid-derived cfr in LRSE are potential key steps to reduce linezolid resistance and its transmission to more pathogenic Gram-positive bacteria.

Twitter: A Platform for Dissemination and Discussion of Scientific Papers in Radiation Oncology.

OBJECTIVE: The objective of this study was to examine the correlation between Twitter mentions and the number of academic citations of radiation oncology articles. MATERIALS AND METHODS: We reviewed all 178 clinical manuscripts of the 2 most important radiation oncology journals and "Brachytherapy," and all clinical manuscripts relating to radiation oncology from the top 10 impact factor oncology journals, published between January and February 2018. We collected the record of citations utilizing Scopus and Google Scholar platforms and the number of times an article was tweeted about using the "Altmetric Bookmarklet." χ test was used to compare distributions between groups and the Pearson coefficient was used for correlations between the Twitter metrics and academic citations. RESULTS: Overall, 71% of all articles were tweeted about at least once. There was a significant correlation between the number of tweets and the number of citations in Google Scholar (r=0.55, P<0.001) and in Scopus (r=0.59, P<0.001). The 11% of articles with a prepublication Twitter "buzz" (defined as an article with ≥10 tweets before publication) had 3.6 times more citations in Scopus (mean: 14.8 vs. 4.2, P<0.001) and 2.9 times more citations in Google Scholar (17.8 vs. 6.0, P<0.001) when compared with papers with no "buzz." CONCLUSIONS: Presence on Twitter was correlated with the number of academic citations of an article in radiation oncology. This suggests that Twitter is being utilized by the oncology community as a platform to discuss and disseminate high impact scientific articles. The correlation between Twitter and increasing the number of citations of an article through larger dissemination and exposure requires further studies.

Women's Representation in Leadership Positions in Academic Medical Oncology, Radiation Oncology, and Surgical Oncology Programs.

Importance: Women are underrepresented in medical leadership positions; however, representation of women among academic oncology leadership is unknown. Objectives: To evaluate representation of women overall and in leadership positions in academic medical oncology (MO), radiation oncology (RO), and surgical oncology (SO) programs and to examine the association of women leadership with overall faculty representation of women per program. Design, Setting, and Participants: In this cross-sectional study, MO, RO, and SO training program websites were queried from October 2018 through June 2019. All faculty from 265 of 273 accredited MO, RO, and SO training programs (97.1%) were included. Exposure: Gender. Main Outcomes and Measures: Observed proportions of women in leadership positions compared with the expected proportion of overall women faculty in MO, RO, and SO were assessed. Rates of representation of women across each MO, RO, and SO program's faculty based on the presence or absence of a woman in a leadership position were compared. Results: Of 6030 total faculty, only 2164 (35.9%) were women. Total representation of women among MO, RO, and SO faculty was 37.1% (1563 of 4215), 30.7% (389 of 1269), and 38.8% (212 of 546), respectively. Women composed only 21.7% (30 of 138), 11.7% (11 of 94), and 3.8% (1 of 26) of MO, RO, and SO chair positions, respectively. The observed proportion of women in chair positions was significantly lower than the expected proportion for MO, RO, and SO. In all, 47.9%, 33%, and 18.5% of MO, RO, and SO programs, respectively, had at least 1 woman in a leadership position (program director or chair). Programs with 1 or more women in a leadership position were associated with a higher mean (SD) percentage of women faculty than those without at least 1 woman leader in MO (40.7% [12.5%] vs 33.1% [11.0%]; P < .001) and RO (36.2% [13.3%] vs 23.4% [12.3%]; P < .001) but not SO (40.2% [15.4%] vs 31.4% [16.9%]; P = .29). Conclusions and Relevance: Gender disparity exists in academic MO, RO, and SO faculty, which is magnified at the chair level. Programs in MO and RO with a woman physician in a leadership position were associated with a higher percentage of women faculty, but this was not true for SO. These data will serve as a benchmark to monitor progress toward a more balanced workforce.

Clinical Cancer Advances 2020: Annual Report on Progress Against Cancer From the American Society of Clinical Oncology.

A MESSAGE FROM ASCO'S PRESIDENT: Shortly before I was elected President of ASCO, I attended the 65th birthday party of a current patient. She had been diagnosed 10 years earlier with metastatic breast cancer and hadn't been sure she wanted to move forward with further treatment. With encouragement, she elected to participate in a clinical trial of an investigational drug that is now widely used to treat breast cancer. Happily, here we were, celebrating with her now-married daughters, their husbands, and three beautiful grandchildren, ages 2, 4, and 8. Such is the importance of clinical trials and promising new therapies.Clinical research is about saving and improving the lives of individuals with cancer. It's a continuing story that builds on the efforts of untold numbers of researchers, clinicians, caregivers, and patients. ASCO's Clinical Cancer Advances report tells part of this story, sharing the most transformative research of the past year. The report also includes our latest thinking on the most urgent research priorities in oncology.ASCO's 2020 Advance of the Year-Refinement of Surgical Treatment of Cancer-highlights how progress drives more progress. Surgery has played a fundamental role in cancer treatment. It was the only treatment available for many cancers until the advent of radiation and chemotherapy. The explosion in systemic therapies since then has resulted in significant changes to when and how surgery is performed to treat cancer. In this report, we explore how treatment successes have led to less invasive approaches for advanced melanoma, reduced the need for surgery in renal cell carcinoma, and increased the number of patients with pancreatic cancer who can undergo surgery.Many research advances are made possible by federal funding. With the number of new US cancer cases set to rise by roughly a third over the next decade, continued investment in research at the national level is crucial to continuing critical progress in the prevention, screening, diagnosis, and treatment of cancer.While clinical research has translated to longer survival and better quality of life for many patients with cancer, we can't rest on our laurels. With ASCO's Research Priorities to Accelerate Progress Against Cancer, introduced last year and updated this year, we've identified the critical gaps in cancer prevention and care that we believe to be most pressing. These priorities are intended to guide the direction of research and speed progress.Of course, the effectiveness or number of new treatments is meaningless if patients don't have access to them. High-quality cancer care, including clinical trials, is out of reach for too many patients. Creating an infrastructure to support patients is a critical part of the equation, as is creating connections between clinical practices and research programs. We have much work to do before everyone with cancer has equal access to the best treatments and the opportunity to participate in research. I know that ASCO and the cancer community are up for this challenge.Sincerely,Howard A. "Skip" Burris III, MD, FACP, FASCOASCO President, 2019-2020.

#WomenWhoCurie: Leveraging Social Media to Promote Women in Radiation Oncology.

The proportion of female trainees in radiation oncology has generally declined despite increasing numbers of female medical students; as a result, radiation oncology is among the bottom 5 specialties in terms of the percentage of female applicants. Recently, social media has been harnessed as a tool to bring recognition to underrepresented groups within medicine and other fields. Inspired by the wide-reaching social media campaign of #ILookLikeASurgeon to promote female physicians, members of the Society for Women in Radiation Oncology penned a new hashtag and launched the #WomenWhoCurie social media campaign on Marie Curie's birthday November 7th, as part of their strategy to raise public awareness. From November 6, 2018 until November 10, 2018, the #WomenWhoCurie hashtag delivered 1,135,000 impressions, including 408 photos from all over the world including United States, Spain, Canada, France, Australia, Ireland, the United Kingdom, Mexico, Japan, the Netherlands, India, Ecuador, Panama, Brazil, and Nigeria. Alongside continued gender disparity research, social media should continue to be used as a tool to engage the community and spur conversations to formulate solutions for gender inequity.

Evaluating Unconscious Bias: Speaker Introductions at an International Oncology Conference.

PURPOSE: In a professional setting, the introduction of female speakers without their professional title may have an impact on the public's perception of the female speaker. We examined how professional titles were used during speakers' introductions at the ASCO Annual Meeting. METHODS: We conducted a retrospective, observational study of video-archived speaker introductions at the 2017 and 2018 ASCO Annual Meetings. A "professional address" was defined as the professional title followed by the speaker's full name or last name. Multivariable logistic regressions were used to identify factors associated with the form of address. RESULTS: Of 2,511 videos reviewed, 781 met inclusion criteria. Female speakers were addressed less often by their professional title compared with male speakers (62% v 81%; P < .001). Males were less likely to use a professional address when introducing female speakers compared with females when introducing male speakers (53% v 80%; P < .01). When women performed speaker introductions, no gender differences in professional address were observed (75% v 82%; P = .13). Female speakers were more likely to be introduced by first name only (17% v 3%; P < .001). Male introducers were more likely to address female speakers by first name only compared with female introducers (24% v 7%; P < .01). In a multivariable regression including gender, degree, academic rank, and geographic location of the speaker's institution, male speakers were more likely to receive a professional address compared with female speakers (odds ratio, 2.43; 95% CI, 1.71 to 3.47; P < .01). CONCLUSION: When introduced by men, female speakers were less likely to receive a professional address and more likely to be introduced by first name only compared with their male peers.

Survival of Patients With Multiple Intracranial Metastases Treated With Stereotactic Radiosurgery: Does the Number of Tumors Matter?

BACKGROUND: Defining prognostic factors is a crucial initial step for determining the management of patients with brain metastases. Randomized trials assessing radiosurgery have commonly limited inclusion criteria to 1 to 4 brain metastases, in part due to multiple retrospective studies reporting on the number of brain metastases as a prognostic indicator. The present study reports on the survival of patients with 1 to 4 versus ≥5 brain metastases treated with radiosurgery. METHODS: We evaluated a retrospective multi-institutional database of 1523 brain metastases in 507 patients who were treated with radiosurgery (Gamma Knife or Cyberknife) between 2001 and 2014. A total of 243 patients were included in the analysis. Patients with 1 to 4 brain metastases were compared with patients with ≥5 brain metastases using a standard statistical analysis. Cox hazard regression was used to construct a multivariable model of overall survival (OS). To find covariates that best separate the data at each split, a machine learning technique Chi-squared Automated Interaction Detection tree was utilized. RESULTS: On Pearson correlation, systemic disease status, number of intracranial metastases, and overall burden of disease (number of major involved organ systems) were found to be highly correlated (P<0.001). Patients with 1 to 4 metastases had a median OS of 10.8 months (95% confidence interval, 6.1-15.6 mo), compared with a median OS of 8.5 months (95% confidence interval, 4.4-12.6 mo) for patients with ≥5 metastases (P=0.143). The actuarial 6 month local failure rate was 5% for patients with 1 to 4 metastases versus 3.2% for patients with ≥5 metastases (P=0.404). There was a significant difference in systemic disease status between the 2 groups; 30% of patients had controlled systemic disease in the <5 lesions group, versus 8% controlled systemic disease in the ≥5 lesions group (P=0.005). Patients with 1 to 4 metastases did not have significantly improved OS in a multivariable model adjusting for systemic disease status, systemic extracranial metastases, and other key variables. The Chi-squared Automated Interaction Detection tree (machine learning technique) algorithm consistently identified performance status and systemic disease status as key to disease classification, but not intracranial metastases. CONCLUSIONS: Although the number of brain metastases has previously been accepted as an independent prognostic indicator, our multicenter analysis demonstrates that the number of intracranial metastases is highly correlated with overall disease burden and clinical status. Proper matching and controlling for these other determinants of survival demonstrates that the number of intracranial metastases alone is not an independent predictive factor, but rather a surrogate for other clinical factors.

Adjuvant radiation for salivary gland malignancies is associated with improved survival: A National Cancer Database analysis.

OBJECTIVE: There are no randomized data to support the use of postoperative radiation for salivary gland malignancies. This study uses the National Cancer Database (NCDB) to describe the epidemiology of salivary gland cancer patients and to investigate whether treatment with adjuvant radiation improves overall survival. METHODS AND MATERIALS: A total of 8243 patients diagnosed with a major salivary gland cancer were identified from the NCDB. All patients received primary surgical resection of their malignancy. Patients were risk-stratified by adverse features, and overall survival rates were determined. Patients were considered high risk if they had extracapsular extension and/or positive margin after resection. Patients were considered intermediate risk if they did not meet the criteria for high risk but had pT3-T4 disease, pN+ disease, lymphovascular space invasion, adenoid cystic histology, or grade 2-3 disease. Patients who did not meet criteria for high or intermediate risk were considered low risk. Overall patient demographics, disease characteristics, treatment factors, and outcomes were summarized with descriptive statistics and analyzed with STATA. RESULTS: Median follow-up in this cohort was 42.4 months, with the median age of 58 years. Patients in the high-risk group had greater survival (hazard ratio [HR], 0.76; P = .002; 95% confidence interval [CI], 0.64-0.91) if they received adjuvant radiation therapy. In contrast, patients in the intermediate- (HR, 1.01; P = .904; 95% CI, 0.85-1.20) and low-risk groups (HR, 0.85; P = .427; 95% CI, 0.57-1.26) did not experience a survival benefit with adjuvant radiation therapy. CONCLUSIONS: This large analysis compared survival outcomes between observation and adjuvant radiation alone in risk-stratified patients after resection of major salivary glands using a national database. The use of adjuvant radiation for high-risk major salivary gland cancers appears to offer a survival benefit. Although an overall survival benefit was not seen in low- and intermediate-risk salivary gland cancers, this study could not address impact on local control because of the limitations of the NCDB.

Palliation of Ulcerative Breast Lesions with Radiation.

BACKGROUND/AIM: Patients with advanced breast cancer may experience ulcerative breast lesions. Breast cancer with ulcerative lesions has been shown to severely affect a patient's quality of life (QoL). The role of palliative radiation therapy (RT) in the management of ulcerative breast lesions needs to be further explored. PATIENTS AND METHODS: We retrospectively reviewed the RT records for all patients who underwent palliative RT for breast cancer at our urban academic medical center. A total of 13 patients were identified, and we herein report their demographics, treatment characteristics, and clinical outcomes. RESULTS: The mean age of the patients receiving palliative RT for ulcerative breast cancer was 64 years. All patients had stage IV disease when they were evaluated for RT. The mean radiation dose received for palliative RT was 27.54 Gy in 11 fractions, with a median dose of 30 Gy in 15 fractions. Six (46%) patients had received prior RT to the same breast, with a median dose of 59.5 Gy in 31 fractions. Among these six patients, the average interval between initial RT and ulceration was 69.5 months. The median overall survival for the whole patient cohort since ulceration was 5 months and the mean survival did not differ between patients with previous history of RT and RT-naïve patients (4.50 vs. 4.57; p=0.95). Six out of the nine (69%) patients who received 30 Gy or more reported clinical improvement, whereas none of the four patients who received less than 30 Gy reported any benefit. There were no radiation-associated toxicities reported by patients. CONCLUSION: These data suggest that palliative RT (≥30 Gy) is an efficacious treatment for ulcerative breast cancer with minimal toxicity. Prior RT should not be a contraindication, as patients with previous history of RT have similar low toxicity rates compared to RT-naïve patients.

The use of isodose levels to interpret radiation induced lung injury: a quantitative analysis of computed tomography changes.

BACKGROUND: Patients treated with stereotactic body radiation therapy (SBRT) for lung cancer are often found to have radiation-induced lung injury (RILI) surrounding the treated tumor. We investigated whether treatment isodose levels could predict RILI. METHODS: Thirty-seven lung lesions in 32 patients were treated with SBRT and received post-treatment follow up (FU) computed tomography (CT). Each CT was fused with the original simulation CT and treatment isodose levels were overlaid. The RILI surrounding the treated lesion was contoured. The RILI extension index [fibrosis extension index (FEI)] was defined as the volume of RILI extending outside a given isodose level relative to the total volume of RILI and was expressed as a percentage. RESULTS: Univariate analysis revealed that the planning target volume (PTV) was positively correlated with RILI volume at FU: correlation coefficient (CC) =0.628 and P<0.0001 at 1(st) FU; CE =0.401 and P=0.021 at 2(nd) FU; CE =0.265 and P=0.306 at 3(rd) FU. FEI -40 Gy at 1(st) FU was significantly positively correlated with FEI -40 Gy at subsequent FU's (CC =0.689 and P=6.5×10(-5) comparing 1(st) and 2(nd) FU; 0.901 and P=0.020 comparing 2(nd) and 3(rd) FU. Ninety-six percent of the RILI was found within the 20 Gy isodose line. Sixty-five percent of patients were found to have a decrease in RILI on the second 2(nd) CT. CONCLUSIONS: We have shown that RILI evolves over time and 1(st) CT correlates well with subsequent CTs. Ninety-six percent of the RILI can be found to occur within the 20 Gy isodose lines, which may prove beneficial to radiologists attempting to distinguish recurrence vs. RILI.