"We need to work towards it, whatever it takes."-participation factors in the acceptability and feasibility of lung cancer screening in Australia: the perspectives of key stakeholders

Background

Low dose computed tomography (LDCT) screening, targeted at those at high-risk, has been shown to significantly reduce lung cancer mortality and detect cancers at an early stage. Practical, attitudinal and demographic factors can inhibit screening participation in high-risk populations. This study aimed to explore stakeholders' views about barriers and enablers (determinants) to participation in lung cancer screening (LCS) in Australia.

Methods

Twenty-four focus groups (range 2-5 participants) were conducted in 2021 using the Zoom platform. Participants were 84 health professionals, researchers, policy makers and program managers of current screening programs. Focus groups consisted of a structured presentation with facilitated discussion lasting about 1 hour. The content was analysed thematically and mapped to the Consolidated Framework for Implementation Research (CFIR).

Results

Screening determinants were identified across each stage of the proposed screening and assessment pathway. Challenges included participant factors such as encouraging participation for individuals at high-risk, whilst ensuring that access and equity issues were carefully considered in program design. The development of awareness campaigns that engaged LCS participants and health professionals, as well as streamlined referral processes for initial entry and follow-up, were strongly advocated for. Considering practical factors included the use of mobile vans in convenient locations.

Conclusions

Participants reported that LCS in Australia was acceptable and feasible. Participants identified a complex set of determinants across the proposed screening and assessment pathway. Strategies that enable the best chance for program success must be identified prior to implementation of a national LCS program.

Current and projected gaps in the availability of radiotherapy in the Asia-Pacific region: a country income-group analysis

BACKGROUND

Cancer incidence and mortality is increasing rapidly worldwide, with a higher cancer burden observed in the Asia-Pacific region than in other regions. To date, evidence-based modelling of radiotherapy demand has been based on stage data from high-income countries (HIC) that do not account for the later stage at presentation seen in many low-income and middle-income countries (LMICs). We aimed to estimate the current and projected demand and supply in megavoltage radiotherapy machines in the Asia-Pacific region, using a national income-group adjusted model.

METHODS

Novel LMIC radiotherapy demand and outcome models were created by adjusting previously developed models that used HIC cancer staging data. These models were applied to the cancer case mix (ie, the incidence of each different cancer) in each LMIC in the Asia-Pacific region to estimate the current and projected optimal radiotherapy utilisation rate (ie, the proportion of cancer cases that would require radiotherapy on the basis of guideline recommendations), and to estimate the number of megavoltage machines needed in each country to meet this demand. Information on the number of megavoltage machines available in each country was retrieved from the Directory of Radiotherapy Centres. Gaps were determined by comparing the projected number of megavoltage machines needed with the number of machines available in each region. Megavoltage machine numbers, local control, and overall survival benefits were compared with previous data from 2012 and projected data for 2040.

FINDINGS

57 countries within the Asia-Pacific region were included in the analysis with 9·48 million new cases of cancer in 2020, an increase of 2·66 million from 2012. Local control was 7·42% and overall survival was 3·05%. Across the Asia-Pacific overall, the current optimal radiotherapy utilisation rate is 49·10%, which means that 4·66 million people will need radiotherapy in 2020, an increase of 1·38 million (42%) from 2012. The number of megavoltage machines increased by 1261 (31%) between 2012 and 2020, but the demand for these machines increased by 3584 (42%). The Asia-Pacific region only has 43·9% of the megavoltage machines needed to meet demand, ranging from 9·9-40·5% in LMICs compared with 67·9% in HICs. 12 000 additional megavoltage machines will be needed to meet the projected demand for 2040.

INTERPRETATION

The difference between supply and demand with regard to megavoltage machine availability has continued to widen in LMICs over the past decade and is projected to worsen by 2040. The data from this study can be used to provide evidence for the need to incorporate radiotherapy in national cancer control plans and to inform governments and policy makers within the Asia-Pacific region regarding the urgent need for investment in this sector.

FUNDING

The Regional Cooperative Agreement for Research, Development and Training Related to Nuclear Science and Technology for Asia and the Pacific (RCA) Regional Office (RCARP03).

A life-course approach to tackling noncommunicable diseases in women

Women's health has been critically underserved by a failure to look beyond women's sexual and reproductive systems to adequately consider their broader health needs. In almost every country in the world, noncommunicable diseases are the leading causes of death for women. Among these, cardiovascular disease (including heart disease and stroke) and cancer are the major causes of mortality. Risks for these conditions exist at each stage of women's lives, but recognition of the unique needs of women for the prevention and management of noncommunicable diseases is relatively recent and still emerging. Once they are diagnosed, treatments for these diseases are often costly and noncurative. Therefore, we call for a strategic, innovative life-course approach to identifying disease triggers and instigating cost-effective measures to minimize exposure in a timely manner. Prohibitive barriers to implementing this holistic approach to women's health exist in both the social arena and the medical arena. Recognizing these impediments and implementing practical approaches to surmounting them is a rational approach to advancing health equity for women, with ultimate benefits for society as a whole.

Hypofractionation Adoption in Prostate Cancer Radiotherapy: Results of an International Survey

PURPOSE

Hypofractionation is noninferior to conventional fractionation in the treatment of localized prostate cancer. Using results from the European Society of Radiation Oncology's (ESTRO) Global Impact of Radiotherapy in Oncology (GIRO) initiative survey on hypofractionation, this study identifies rates of adoption, facilitating factors, and barriers to adoption of hypofractionation in prostate cancer across World Bank income groups.

MATERIALS AND METHODS

The ESTRO-GIRO initiative administered an international, anonymous, electronic survey to radiation oncologists from 2018 to 2019. Physician demographics, clinical practice characteristics, and hypofractionation regimen use (if any) for several prostate cancer scenarios were collected. Responders were asked about specific justifications and barriers to adopting hypofractionation, and responses were stratified by World Bank income group. Multivariate logistic regression models were used to analyze variables associated with hypofractionation preference.

RESULTS

A total of 1,157 physician responses were included. Most respondents (60%) were from high-income countries (HICs). In the curative setting, hypofractionation was most often preferred in low- and intermediate-risk prostate cancers, with 52% and 47% of respondents reporting hypofractionation use in ≥50% of patients, respectively. These rates drop to 35% and 20% in high-risk prostate cancer and where pelvic irradiation is indicated. Most respondents (89%) preferred hypofractionation in the palliative setting. Overall, respondents from upper-middle-income countries and lower-middle- and low-income countries were significantly less likely to prefer hypofractionation than those from HICs (P < .001). The most frequently cited justification and barrier were availability of published evidence and fear of worse late toxicity, respectively.

CONCLUSION

Hypofractionation preference varies by indication and World Bank income group, with greater acceptance among providers in HICs for all indications. These results provide a basis for targeted interventions to increase provider acceptance of this treatment modality.

Radiation Therapy and Indigenous Peoples in Canada and Australia: Building Paths Toward Reconciliation in Cancer Care Delivery

Indigenous peoples represent approximately 5% of the world's population and reside in over 90 countries worldwide. They embody a rich diversity of cultures, traditions, languages and relationships with the land that are shared through many generations and that are distinct from those of the settler societies within which they now live. Many Indigenous peoples have a shared experience of discrimination, trauma, and violation of rights, rooted in complex sociopolitical relationships with settler societies that are still ongoing. This results in continuing social injustices and pronounced disparities in health for many Indigenous peoples around the globe. Indigenous peoples exhibit a significantly higher cancer incidence, mortality, and poorer survival compared to non-Indigenous peoples. Cancer services, including radiotherapy, have not been designed to support the specific values and needs of Indigenous populations, resulting in poorer access to cancer services for Indigenous peoples globally across the entire cancer care spectrum. Specific to radiotherapy, available evidence demonstrates disparities in radiotherapy uptake between Indigenous and non-Indigenous patients. Radiotherapy centres are also located disparately further away from Indigenous communities. Studies are limited by a lack of Indigenous-specific data to help inform effective radiotherapy delivery. Recent Indigenous-led partnerships and initiatives have helped to address existing gaps in cancer care, and radiation oncologists play an important role in supporting such efforts. In this article, we present an overview of access to radiotherapy for Indigenous peoples in Canada and Australia, with a focus on strengthening cancer care delivery through education, partnerships, and research.

Radiology and radiation oncology considerations for transgender and intersex patients: A qualitative study

INTRODUCTION

In this qualitative study, we explored experiences of radiologists and radiation oncologists in providing clinical care to transgender, gender diverse (TGD), and intersex patients by asking about comfort level, relevant past training and training gaps, and clinical recommendations for TGD and intersex patient care.

METHODS

A purposive sample of radiology and radiation oncology professionals (n = 16) from diverse practice settings were interviewed on a videoconferencing platform. Transcripts were auto-populated and checked manually for accuracy. Two coders used a mix of deductive and inductive coding to identify key themes. Member checking was conducted with interviewees.

RESULTS

Participants reported major gaps in training, knowledge, and confidence related to all aspects of TGD and intersex patient care. Recommendations for improvements included training that encompassed key terminology, how to conduct a physical exam on TGD and intersex patients, radiology and radiation oncology adaptations for TGD and intersex patients, and care coordination among multi-disciplinary oncology team members and gender affirming care providers. Exposure to diverse TGD and intersex persons in personal and professional life contributed to higher levels of comfort among providers in caring for TGD and intersex patients.

CONCLUSION

Gaps in knowledge and limited confidence characterized the sample. Training at all levels is needed to improve radiology and radiation oncology care for TGD and intersex patients.

"What do I think about implementing lung cancer screening? It all depends on how." Acceptability and feasibility of lung cancer screening in Australia: The view of key stakeholders about health system factors

BACKGROUND

Lung cancer is the number one cause of cancer death worldwide. Although international trials demonstrate that targeted screening using low dose computed tomography (LDCT) significantly reduces lung cancer mortality, implementation of screening in the high-risk population presents complex health system challenges that need to be thoroughly understood to support policy change.

AIM

To elicit health care providers' and policymakers' views about the acceptability and feasibility of lung cancer screening (LCS) and barriers and enablers to implementation in the Australian setting.

METHODS

We conducted 24 focus groups and three interviews (22 focus groups and all interviews online) in 2021 with 84 health professionals, researchers, and current cancer screening program managers and policy makers across all Australian states and territories. Focus groups included a structured presentation about lung cancer and screening and lasted approximately one hour each. A qualitative approach to analysis was used to map topics to the Consolidated Framework for Implementation Research.

RESULTS

Nearly all participants considered LCS to be acceptable and feasible but identified a wide range of implementation challenges. Topics (five specific to health systems and five cross-cutting with participant factors) identified were mapped to CFIR constructs, of which 'readiness for implementation', 'planning' and 'executing' were most salient. Health system factor topics included delivery of the LCS program, cost, workforce considerations, quality assurance and complexity of health systems. Participants strongly advocated for streamlined referral processes. Practical strategies to address equity and access, such as using mobile screening vans, were emphasised.

CONCLUSIONS

Key stakeholders readily identified the complex challenges associated with the acceptability and feasibility of LCS in Australia. The barriers and facilitators across health system and cross-cutting topics were clearly elicited. These findings are highly relevant to the scoping of a national LCS program by the Australian Government and a subsequent recommendation for implementation.

Hypofractionation in Breast Cancer Radiotherapy Across World Bank Income Groups: Results of an International Survey

PURPOSE

Hypofractionated breast radiotherapy has been found to be equivalent to conventional fractionation in many clinical trials. Using data from the European Society for Radiotherapy and Oncology Global Impact of Radiotherapy in Oncology survey, we identified preferences for hypofractionation in breast cancer across World Bank income groups and the perceived facilitators and barriers to its use.

MATERIALS AND METHODS

An international, electronic survey was administered to radiation oncologists from 2018 to 2019. Demographics, practice characteristics, preferred hypofractionation regimen for specific breast cancer scenarios, and facilitators and barriers to hypofractionation were reported and stratified by World Bank income groups. Variables associated with hypofractionation were assessed using multivariate logistic regression models.

RESULTS

One thousand four hundred thirty-four physicians responded: 890 (62%) from high-income countries (HICs), 361 (25%) from upper-middle-income countries (UMICs), 183 (13%) from low- and lower-middle-income countries (LLMICs). Hypofractionation was preferred most frequently in node-negative disease after breast-conserving surgery, with the strongest preference reported in HICs (78% from HICs, 54% from UMICs, and 51% from LLMICs, P < .001). Hypofractionation for node-positive disease postmastectomy was more frequently preferred in LLMICs (28% from HICs, 15% from UMICs, and 35% from LLMICs, P < .001). Curative doses of 2.1 to < 2.5 Gy in 15-16 fractions were most frequently reported, with limited preference for ultra-hypofractionation, but significant variability in palliative dosing. In adjusted analyses, UMICs were significantly less likely than LLMICs to prefer hypofractionation across all curative clinical scenarios, whereas respondents with > 1 million population catchments and with intensity-modulated radiotherapy were more likely to prefer hypofractionation. The most frequently cited facilitators and barriers were published evidence and fear of late toxicity, respectively.

CONCLUSION

Preference for hypofractionation varied for curative indications, with greater acceptance in earlier-stage disease in HICs and in later-stage disease in LLMICs. Targeted educational interventions and greater inclusivity in radiation oncology clinical trials may support greater uptake.

Radiotherapy prioritization in 143 national cancer control plans: Correlation with radiotherapy machine availability, geography and income level

BACKGROUND

In 2015, the Global Task Force on Radiotherapy for Cancer Control (GTFRCC) called for 80% of National Cancer Control Plans (NCCP) to include radiotherapy by 2020. As part of the ongoing ESTRO Global Impact of Radiotherapy in Oncology (GIRO) project, we assessed whether inclusion of radiotherapy in NCCPs correlates with radiotherapy machine availability, national income, and geographic region.

METHODS

A previously validated checklist was used to determine whether radiotherapy was included in each country's NCCP. We applied the CCORE optimal radiotherapy utilisation model to the GLOBOCAN 2020 data to estimate the demand for radiotherapy and compared this to the International Atomic Energy Agency (IAEA) Directory of Radiotherapy Centres (DIRAC) supply data, stratifying by income level and world region. World regions were defined according to the IAEA.

FINDINGS

Complete data (including GLOBOCAN 2020, DIRAC and NCCP) was available for 143 countries. Over half (55%, n = 79) included a radiotherapy-specific checklist item within the plan. Countries which included radiotherapy services planning in their NCCP had a higher median number of machines (1.68 vs 0.75 machines/1000 patients needing radiotherapy, p < 0.001). There was significant regional and income-level heterogeneity in the inclusion of radiotherapy-related items in NCCPs. Low-income and Asia-Pacific countries were least likely to include radiation oncology services planning in their NCCP (p = 0.06 and p = 0.003, respectively). Few countries in the Asia-Pacific (18.6%) had a plan to develop or maintain radiation services, compared to 57% of countries in Europe.

INTERPRETATION

Only 55% of current NCCPs included any information regarding radiotherapy, below the GTFRCC's target of 80%. Prioritisation of radiotherapy in NCCPs was correlated with radiotherapy machine availability. There was regional and income-level heterogeneity regarding the inclusion of specific radiotherapy checklist items in the NCCPs. Ongoing efforts are needed to promote the inclusion of radiotherapy in future iterations of NCCPs in order to improve global access to radiation treatment.

FUNDING

No direct funding was used in this research.

Variability of gross tumour volume delineation: MRI and CT based tumour and lymph node delineation for Lung radiotherapy

PURPOSE

To compare gross tumour volume (GTV) delineation of lung cancer on magnetic resonance imaging (MRI) and positron emission tomography (PET) versus computed tomography (CT) and PET.

METHODS

Three experienced thoracic radiation oncologists delineated GTVs on twenty-six patients with lung cancer, based on CT registered to PET, T2-weighted MRI registered to PET and T1-weighted MRI registered with PET. All observers underwent education on reviewing T1 and T2 images along with guidance on window and level setup. Interobserver and intermodality variation was performed based ondice similarity coefficient (DSC), Hausdorff distance (HD), and average Hausdorff distance (AvgHD) metrics. To compute interobserver variability (IOV) a simultaneous truth and performance level estimation (STAPLE) volume for each image modality was used as reference volume. For intermodality analysis, each observers CT based primary and nodal GTV was used as reference volume.

RESULTS

A mean DSC of 0.9 across all observers for primary GTV (GTVp) and a DSC of > 0.7 for nodal GTV (GTVn) was demonstrated for IOV. Mean T2 and T1 GTVp and GTVn were smaller than CT GTVp and GTVn but the difference in volume between modalities was not statistically significant. Significant difference (p<0.01) for GTVp and GTVn was found between T2 and T1 GTVp and GTVn compared to CT GTVp and GTVn based on DSC metrics. Large variation in volume similarity was noted based on HD of up-to 5.4cm for observer volumes compared to STAPLE volume.

CONCLUSION

Interobserver variability in GTV delineation was similar for MRI and PET versus CT and PET. The significant difference between MRI compared to CT delineated volumes needs to be further explored.

Lung cancer treatment patterns and factors relating to systemic therapy use in Australia

AIM

Systemic therapies for lung cancer are rapidly evolving. This study aimed to describe lung cancer treatment patterns in New South Wales, Australia, prior to the introduction of immunotherapy and latest-generation targeted therapies.

METHODS

Systemic therapy utilization and treatment-related factors were examined for participants in the New South Wales 45 and Up Study with incident lung cancer ascertained by record linkage to the New South Wales Cancer Registry (2006-2013). Systemic therapy receipt to June 2016 was determined using medical and pharmaceutical claims data from Services Australia, and in-patient hospital records. Factors related to treatment were identified using competing risks regressions.

RESULTS

A total of 1,116 lung cancer cases were identified with a mean age at diagnosis of 72 years and median survival of 10.6 months. Systemic therapy was received by 45% of cases. Among 400 cases with metastatic non-small cell lung cancer, 51% and 28% received first- and second-line systemic therapy, respectively. Among 112 diagnosed with small-cell lung cancer, 79% and 29% received first- and second-line systemic therapy. The incidence of systemic therapy was lower for participants with indicators of poor performance status, lower educational attainment, and those who lived in areas of socioeconomic disadvantage; and was higher for participants with small-cell lung cancer histology or higher body mass index.

CONCLUSION

This population-based Australian study identified patterns of systemic therapy use for lung cancer, particularly small-cell lung cancer. Despite a universal healthcare system, the analysis revealed socioeconomic disparities in health service utilization and relatively low utilization of systemic therapy overall.

Distribution of pathogenic Leptospira in environmental water and soils of selected recreational forests in Perak, Malaysia

Leptospirosis is an emerging zoonotic disease endemic in tropical regions. Aiming at assessing the potential infection risks via recreational exposure, the molecular prevalence of pathogenic Leptospira in 14 amenity forests in five selected districts of the state of Perak was determined. Water and soil samples along streams and waterfalls were subjected to culture of leptospires and the pathogenic Leptospira spp. was detected by lipL32-based polymerase chain reaction (PCR). Twenty out of 154 samples (13%) that tested positive for leptospires were mostly soils and still water recorded with tolerable temperatures (22.2- 26.5°C) and pHs (5.73-6.70). The localised prevalence was highly varied among eight positive forests (6.7-41.7%), particularly higher in Kampar and Kinta districts which are the more populated urban areas. The importance of public health surveillance should not be underrated given the high prevalence of Leptospira spp. in forests in close proximity to indigenous settlements, even where the places are clean. Overall, this study discovered a wide distribution of pathogenic Leptospira spp. in recreational areas.

Implementation of 3D conformal radiotherapy technology at the National Cancer Centre Mongolia: A successful Asia-Pacific collaborative initiative

INTRODUCTION

Mongolia has a population of 3.3 million and is classified by the WHO as a lower middle-income country. Cancer is now a major public health issue and one of the leading causes of mortality. Within the framework of an existing national cancer control plan, the National Cancer Centre of Mongolia (NCCM) aimed to implement 3D conformal radiation planning and linac-based treatment delivery.

METHODS

In 2018, an opportunity arose for collaboration between the Mongolia Society for Radiation Oncology (MOSTRO), the National Cancer Centre Mongolia (NCCM), the Asia-Pacific Radiation Oncology Special Interest Group (APROSIG) of the Royal Australian and New Zealand College of Radiologists (RANZCR) and the Asia-Pacific Special Interest Group (APSIG) of the Australasian College of Physical Scientists and Engineers in Medicine (ACPSEM) and radiation therapists (RTTs) from a range of Australian centres. We describe here the results to date of this collaboration.

RESULTS

Despite a number of significant technical and practical barriers, successful linac commissioning was achieved in 2019. Key factors for success included a leadership receptive to change management, stable bureaucracy and health systems, as well as a synchronised effort, regional cooperation and mentorship.

CONCLUSION

Future directions for ongoing collaborative efforts include a continued focus on education, practical training in radiotherapy planning and delivery and postgraduate education initiatives. Radiotherapy safety and quality assurance remain an ongoing priority, particularly as technological advances are sequentially implemented.

Equity should know no borders: The role of Australasian radiation oncologists in supporting radiation oncology services in low- and middle-income countries in the Asia-Pacific

The rapid rise in cancer incidence within the world's poorest nations highlights the need for equitable access to evidence-based cancer care. It has been previously demonstrated that radiotherapy is a cost-effective and necessary tool in cancer treatment. However, globally there is a growing divide between demand and supply of radiotherapy services. In low- and middle-income countries, this resource gap is particularly problematic. By region, the Asia-Pacific has been demonstrated to have the highest absolute deficit in radiotherapy services. Radiation oncologists in Australia and New Zealand are geographically well positioned to assist departments within the Asia-Pacific to help to reduce these inequities. The Asia-Pacific Radiation Oncology Special Interest Group (APROSIG) aims to support oncology professionals in the Asia-Pacific to develop safe and sustainable cancer services. Members have already contributed to multiple projects throughout the region, supported by grants and departmental funding. However, the backbone of support comes from volunteers sharing their time and expertise. The Australasian oncological community has the skills and knowledge to help not only those within our borders but also beyond. Such efforts provide the potential to develop valuable clinical, educational, research and leadership experiences whilst establishing networking opportunities throughout the most populated regions of the world. More options for growth and work in global health must be investigated, encouraging future trainees to consider a role within the global cancer community. Without prompt and continued action, the resource deficit is likely to grow and the inequity in accessing radiotherapy and other cancer services further magnified.

Patterns of care for men with prostate cancer: the 45 and Up Study

OBJECTIVES

To describe patterns of care in New South Wales for men with prostate cancer, and to ascertain factors associated with receiving different types of treatment.

DESIGN

Individual patient data record linkage study.

SETTING, PARTICIPANTS

4003 New South Wales men aged 45 years or more enrolled in the population-based 45 and Up Study in whom prostate cancer was first diagnosed during 2006-2013.

MAIN OUTCOME MEASURES

Prostate cancer treatment type received; factors statistically associated with treatment received; proportions of patients who consulted radiation oncologists prior to treatment.

RESULTS

In total, 1619 of 4003 patients underwent radical prostatectomy (40%), 893 external beam radiotherapy (EBRT) (22%), 183 brachytherapy (5%), 87 chemotherapy (2%), 373 androgen deprivation therapy alone (9%), and 848 no active treatment (21%). 205 of 1628 patients who had radical prostatectomies (13%) had radiation oncology consultations prior to surgery. Radical prostatectomy was more likely for patients aged 45-59 years, with regional stage disease, living 100 km or more from the nearest radiotherapy centre, having partners, or having private health insurance, while lower physical functioning, obesity, and living in areas of greater socio-economic disadvantage reduced the likelihood. EBRT was more likely for patients aged 70-79 years, with non-localised or unknown stage disease, living less than 100 km from the nearest radiotherapy centre, or not having private health insurance, while the likelihood was lower for patients aged 45-59 years or more than 80 years and for those who had several comorbid conditions.

CONCLUSIONS

Men with prostate cancer were twice as likely to have radical prostatectomy as to receive EBRT, and fewer than one in seven had consulted radiation oncologists prior to prostatectomy. The treatment received was influenced by several socio-demographic factors. Given the treatment-specific side effects and costs, policies that affect access to different treatments for prostate cancer should be reviewed.

Australia and New Zealand's responsibilities in improving oncology services in the Asia-Pacific: A call to action

AIM

To review the expected increasing demand for cancer services among low and middle-income countries (LMICs) in the Asia-Pacific (APAC), and to describe ways in which Australia and New Zealand (ANZ) can provide support to improve cancer outcomes in our region.

METHODS

We first review the current and projected incidence of cancer within the APAC between 2018 and 2040, and the estimated demand for chemotherapy, radiotherapy and surgery. We then explore potential ways in which ANZ can increase regional collaborations to improve cancer outcomes.

RESULTS

We identify 6 ways that ANZ can collaborate with LMICs to improve cancer care in the APAC through the ANZ Regional Oncology Collaboration Strategy: Increasing education and institutional collaborations in the APAC region through in-country training, twinning partnerships, observerships and formalised training programs in order to increase cancer care quality and capacity. Promoting and assisting in the establishment and maintenance of population-based cancer registries in LMICs. Increasing research capacity in LMICs through collaboration and promoting high quality global oncology research within ANZ. Engaging and training Australian and New Zealand clinicians in global oncology, increasing awareness of this important career path, and increasing health policy engagement. Increasing web-based endeavours through virtual tumour boards, web-based advocacy platforms and web-based teaching programs. Continuing to leverage for funding through professional bodies, government, industry, not-for-profit organisations and local hospital funds.

CONCLUSION

We propose the creation of an Australian and New Zealand Interest Group to provide formalised and sustained collaboration between researchers, clinicians and stakeholders.

Hypofractionated radiotherapy in the real-world setting: An international ESTRO-GIRO survey

BACKGROUND AND PURPOSE

Multiple large trials have established the non-inferiority of hypofractionated radiotherapy compared to conventional fractionation. This study will determine real-world hypofractionation adoption across different geographic regions for breast, prostate, cervical cancer, and bone metastases, and identify barriers and facilitators to its use.

MATERIALS AND METHODS

An anonymous, electronic survey was distributed from January 2018 through January 2019 to radiation oncologists through the ESTRO-GIRO initiative. Predictors of hypofractionation were identified in univariable and multivariable regression analyses.

RESULTS

2316 radiation oncologists responded. Hypofractionation was preferred in node-negative breast cancer following lumpectomy (82·2% vs. 46·7% for node-positive; p < 0.001), and in low- and intermediate-risk prostate cancer (57·5% and 54·5%, respectively, versus 41·2% for high-risk (p < 0.001)). Hypofractionation was used in 32·3% of cervix cases in Africa, but <10% in other regions (p < 0.001). For palliative indications, hypofractionation was preferred by the majority of respondents. Lack of long-term data and concerns about local control and toxicity were the most commonly cited barriers. In adjusted analyses, hypofractionation was least common for curative indications amongst low- and lower-middle-income countries, Asia-Pacific, female respondents, small catchment areas, and in centres without access to intensity modulated radiotherapy.

CONCLUSION

Significant variation was observed in hypofractionation across curative indications and between regions, with greater concordance in palliation. Using inadequate fractionation schedules may impede the delivery of affordable and accessible radiotherapy. Greater regionally-targeted and disease-specific education on evidence-based fractionation schedules is needed to improve utilization, along with best-case examples addressing practice barriers and supporting policy reform.

Factors Associated With Radiotherapy Utilisation In New South Wales, Australia: Results From The 45 and Up Study

AIMS

Actual radiotherapy utilisation rates tend to be lower than the estimated optimal rates. Little is known about the factors contributing to this difference. Our aim was to identify factors associated with radiotherapy receipt for a cohort of cancer patients in New South Wales (NSW), Australia.

MATERIALS AND METHODS

In total, 267 153 participants in the NSW 45 and Up Study completed a questionnaire during 2006-2009 providing detailed health and socio-demographic information and consented to record linkage with administrative health datasets. Single primary cancers diagnosed after study enrolment were identified through linkage with the NSW Cancer Registry to December 2013. Radiotherapy receipt was determined from claims to the Medicare Benefits Schedule and/or records in the NSW Admitted Patient Data Collection (2006 to June 2016). Competing risks regression was used to examine associations between health and socio-demographic characteristics and radiotherapy treatment.

RESULTS

Of 17 873 patients with an incident cancer, 5414 (30.3%) received radiotherapy during follow-up (median 5.3 years). Patients less likely to receive radiotherapy were aged <60 or 80+ years, female, had a Charlson co-morbidity index of 1+, needed help with daily tasks or lived ≥100 km from the nearest radiotherapy centre.

CONCLUSION

Distinct subgroups of patients are less likely to receive radiotherapy. Advocacy and/or policy changes are needed to improve access.

Contributions of prognostic factors to socioeconomic disparities in cancer survival: protocol for analysis of a cohort with linked data

INTRODUCTION

Socioeconomic disparities in cancer survival have been reported in many developed countries, including Australia. Although some international studies have investigated the determinants of these socioeconomic disparities, most previous Australian studies have been descriptive, as only limited relevant data are generally available. Here, we describe a protocol for a study to use data from a large-scale Australian cohort linked with several other health-related databases to investigate several groups of factors associated with socioeconomic disparities in cancer survival in New South Wales (NSW), Australia, and quantify their contributions to the survival disparities.

METHODS AND ANALYSIS

The Sax Institute's 45 and Up Study participants completed a baseline questionnaire during 2006-2009. Those who were subsequently diagnosed with cancer of the colon, rectum, lung or female breast will be included. This study sample will be identified by linkage with NSW Cancer Registry data for 2006-2013, and their vital status will be determined by linking with cause of death records up to 31 December 2015. The study cohort will be divided into four groups based on each of the individual education level and an area-based socioeconomic measure. The treatment received will be obtained through linking with hospital records and Medicare and pharmaceutical claims data. Cox proportional hazards models will be fitted sequentially to estimate the percentage contributions to overall socioeconomic survival disparities of patient factors, tumour and diagnosis factors, and treatment variables.

ETHICS AND DISSEMINATION

This research is covered by ethical approval from the NSW Population and Health Services Research Ethics Committee. Results of the study will be disseminated to different interest groups and organisations through scientific conferences, social media and peer-reviewed articles.

Global Collaborations for Cervical Cancer: Can the East-West Alliance Facilitate Treatment for all?

Despite the advances in the primary prevention of cervical cancer, there is an absolute increase in the incidence of cervical cancer as a result of an increase in world population. A vast majority of patients in low and low-middle income countries continue to present at a locally advanced stage, necessitating treatment with chemoradiation and brachytherapy. There is a dearth of equipment and trained professionals for the treatment of cervical cancer, especially in low and low-middle income countries. There is an urgent need to improve treatment availability and develop better treatments. Worldwide trends, however, reveal a low number of therapeutic and innovative research trials in cervical cancer. The present article elucidates the existing challenges and provides solutions to improve outcomes. The proposed strategies hinge on strengthening collaborations for global advocacy.

Estimates of global chemotherapy demands and corresponding physician workforce requirements for 2018 and 2040: a population-based study

BACKGROUND

The incidence of cancer (excluding non-melanomatous skin cancers) is projected to rise from 17·0 million to 26·0 million between 2018 and 2040. A large proportion of these patients would be likely to derive benefit from chemotherapy, but no studies so far have quantified current and projected global chemotherapy demands. We aimed to estimate changes in national, regional, and global demands for first-course chemotherapy and the cancer physician workforce between 2018 and 2040 if all patients were treated according to best-practice evidence-based guidelines.

METHODS

Data for the incidence of 29 types of cancer in 183 countries in 2018, and projections of incidence in 2040, were obtained from GLOBOCAN 2018. Optimal chemotherapy utilisation from evidence-based guidelines was applied to these incidence data to generate the number of new patients requiring first-course chemotherapy in 2018 and 2040. We then estimated the corresponding cancer physician workforce required to deliver this chemotherapy (on the basis of physicians seeing 150 new patients requiring chemotherapy per year). We did sensitivity analyses to investigate how cancer stage at presentation affected chemotherapy demands. We also did sensitivity analyses to explore changes to workforce requirements if each physician was seeing 100 new patients requiring chemotherapy per year or 300 new patients requiring chemotherapy per year.

FINDINGS

Between 2018 and 2040, the number of patients requiring first-course chemotherapy annually will increase from 9·8 million to 15·0 million, a relative increase of 53%. The estimated proportion of patients needing chemotherapy who reside in low-income or middle-income countries was 63% (6 162 240 of 9 782 783) in 2018, and will be 67% (10 071 049 of 14 984 560) in 2040. The most common indications for chemotherapy worldwide in 2040 will be lung cancer (accounting for 2 455 137 [16·4%] of 14 984 560 cases eligible for chemotherapy), breast cancer (1 898 740 [12·7%]), and colorectal cancer (1 678 153 [11·1%]). We estimated that, in 2018, 65 000 cancer physicians were required worldwide to deliver optimal chemotherapy-a figure that we estimate will rise to 100 000 by 2040 (with estimates ranging from from 50 000 to 150 000, depending on workload).

INTERPRETATION

Strategic investments in chemotherapy service provision and cancer physicians are needed to meet the projected increased demand for chemotherapy in 2040.

FUNDING

None.

Variations in breast cancer histology and treatment patterns between the major ethnic groups of South West Sydney

Studies in the United States and United Kingdom have demonstrated ethnic variations in breast cancer receptor status, histology, and treatment access. This study aimed to investigate whether ethnicity variation similarly exists in Australia. Patients diagnosed with breast cancer between 2006 and 2011 across all public hospitals in the South Western Sydney Local Health District were identified and patient data collected retrospectively. Logistic regression analysis was used to measure the association between various biologic and treatment parameters and ethnicity. Ethnicity was found to have an influence on age of diagnosis, histology, treatment utilization, and recurrence in breast cancer patients.

The impact of imaging modality (CT vs MRI) and patient position (supine vs prone) on tangential whole breast radiation therapy planning

PURPOSE

The purpose of this study was to evaluate the impact of magnetic resonance imaging (MRI) versus computed tomography (CT)-derived planning target volumes (PTVs), in both supine and prone positions, for whole breast (WB) radiation therapy.

METHODS AND MATERIALS

Four WB radiation therapy plans were generated for 28 patients in which PTVs were generated based on CT or MRI data alone in both supine and prone positions. A 6-MV tangential intensity modulated radiation therapy technique was used, with plans designated as ideal, acceptable, or noncompliant. Dose metrics for PTVs and organs at risk were compared to analyze any differences based on imaging modality (CT vs MRI) or patient position (supine vs prone).

RESULTS

With respect to imaging modality 2/11 whole breast planning target volume (WB_PTV) dose metrics (percentage of PTV receiving 90% and 110% of prescribed dose) displayed statistically significant differences; however, these differences did not alter the average plan compliance rank. With respect to patient positioning, the odds of having an ideal plan versus a noncompliant plan were higher for the supine position compared with the prone position (P = .026). The minimum distance between the seroma cavity planning target volume (SC_PTV) and the chest wall was increased with prone positioning (P < .001, supine and prone values 1.1 mm and 8.7 mm, respectively). Heart volume was greater in the supine position (P = .005). Heart doses were lower in the supine position than prone (P < .01, mean doses 3.4 ± 1.55 Gy vs 4.4 ± 1.13 Gy for supine vs prone, respectively). Mean lung doses met ideal dose constraints in both positions, but were best spared in the prone position. The contralateral breast maximum dose to 1cc (D1cc) showed significantly lower doses in the supine position (P < .001, 4.64 Gy vs 9.51 Gy).

CONCLUSIONS

Planning with PTVs generated from MRI data showed no clinically significant differences from planning with PTVs generated from CT with respect to PTV and doses to organs at risk. Prone positioning within this study reduced mean lung dose and whole heart volumes but increased mean heart and contralateral breast doses compared with supine.

The Benefits of Providing External Beam Radiotherapy in Low- and Middle-income Countries

More than half of all cancer diagnoses worldwide occur in low- and middle-income countries (LMICs) and the incidence is projected to rise substantially within the next 20 years. Radiotherapy is a vital, cost-effective treatment for cancer; yet there is currently a huge deficit in radiotherapy services within these countries. The aim of this study was to estimate the potential outcome benefits if external beam radiotherapy was provided to all patients requiring such treatment in LMICs, according to the current evidence-based guidelines. Projected estimates of these benefits were calculated to 2035, obtained by applying the previously published Collaboration for Cancer Outcomes, Research and Evaluation (CCORE) demand and outcome benefit estimates to cancer incidence and projection data from the GLOBOCAN 2012 data. The estimated optimal radiotherapy utilisation rate for all LMICs was 50%. There were about 4.0 million cancer patients in LMICs who required radiotherapy in 2012. This number is projected to increase by 78% by 2035, a far steeper increase than the 38% increase expected in high-income countries. National radiotherapy benefits varied widely, and were influenced by case mix. The 5 year population local control and survival benefits for all LMICs, if radiotherapy was delivered according to guidelines, were estimated to be 9.6% and 4.4%, respectively, compared with no radiotherapy use. This equates to about 1.3 million patients who would derive a local control benefit in 2035, whereas over 615 000 patients would derive a survival benefit if the demand for radiotherapy in LMICs was met. The potential outcome benefits were found to be higher in LMICs. These results further highlight the urgent need to reduce the gap between the supply of, and demand for, radiotherapy in LMICs. We must attempt to address this 'silent crisis' as a matter of priority and the approach must consider the complex societal challenges unique to LMICs.

MRI geometric distortion: Impact on tangential whole-breast IMRT

The purpose of this study was to determine the impact of magnetic resonance imaging (MRI) geometric distortions when using MRI for target delineation and planning for whole-breast, intensity-modulated radiotherapy (IMRT). Residual system distortions and combined systematic and patient-induced distortions are considered. This retrospective study investigated 18 patients who underwent whole-breast external beam radiotherapy, where both CT and MRIs were acquired for treatment planning. Distortion phantoms were imaged on two MRI systems, dedicated to radiotherapy planning (a wide, closed-bore 3T and an open-bore 1T). Patient scans were acquired on the 3T system. To simulate MRI-based planning, distortion maps representing residual system distortions were generated via deformable registration between phantom CT and MRIs. Patient CT images and structures were altered to match the residual system distortion measured by the phantoms on each scanner. The patient CTs were also registered to the corresponding patient MRI scans, to assess patient and residual system effects. Tangential IMRT plans were generated and optimized on each resulting CT dataset, then propagated to the original patient CT space. The resulting dose distributions were then evaluated with respect to the standard clinically acceptable DVH and visual assessment criteria. Maximum residual systematic distortion was measured to be 7.9 mm (95%<4.7mm) and 11.9 mm (95%<4.6mm) for the 3T and 1T scanners, respectively, which did not result in clinically unacceptable plans. Eight of the plans accounting for patient and systematic distortions were deemed clinically unacceptable when assessed on the original CT. For these plans, the mean difference in PTV V95 (volume receiving 95% prescription dose) was 0.13±2.51% and -0.73±1.93% for right- and left-sided patients, respectively. Residual system distortions alone had minimal impact on the dosimetry for the two scanners investigated. The combination of MRI systematic and patient-related distortions can result in unacceptable dosimetry for whole-breast IMRT, a potential issue when considering MRI-only radiotherapy treatment planning. PACS number(s): 87.61.-c, 87.57.cp, 87.57.nj, 87.55.D.

Comparison of Magnetic Resonance Imaging and Computed Tomography for Breast Target Volume Delineation in Prone and Supine Positions

PURPOSE

To determine whether T2-weighted MRI improves seroma cavity (SC) and whole breast (WB) interobserver conformity for radiation therapy purposes, compared with the gold standard of CT, both in the prone and supine positions.

METHODS AND MATERIALS

Eleven observers (2 radiologists and 9 radiation oncologists) delineated SC and WB clinical target volumes (CTVs) on T2-weighted MRI and CT supine and prone scans (4 scans per patient) for 33 patient datasets. Individual observer's volumes were compared using the Dice similarity coefficient, volume overlap index, center of mass shift, and Hausdorff distances. An average cavity visualization score was also determined.

RESULTS

Imaging modality did not affect interobserver variation for WB CTVs. Prone WB CTVs were larger in volume and more conformal than supine CTVs (on both MRI and CT). Seroma cavity volumes were larger on CT than on MRI. Seroma cavity volumes proved to be comparable in interobserver conformity in both modalities (volume overlap index of 0.57 (95% Confidence Interval (CI) 0.54-0.60) for CT supine and 0.52 (95% CI 0.48-0.56) for MRI supine, 0.56 (95% CI 0.53-0.59) for CT prone and 0.55 (95% CI 0.51-0.59) for MRI prone); however, after registering modalities together the intermodality variation (Dice similarity coefficient of 0.41 (95% CI 0.36-0.46) for supine and 0.38 (0.34-0.42) for prone) was larger than the interobserver variability for SC, despite the location typically remaining constant.

CONCLUSIONS

Magnetic resonance imaging interobserver variation was comparable to CT for the WB CTV and SC delineation, in both prone and supine positions. Although the cavity visualization score and interobserver concordance was not significantly higher for MRI than for CT, the SCs were smaller on MRI, potentially owing to clearer SC definition, especially on T2-weighted MR images.

Global Access to Radiotherapy Services: Have We Made Progress During the Past Decade?

PURPOSE

The global incidence of cancer is rising, particularly in low- and middle-income countries. Radiotherapy is an important cancer treatment in the curative and palliative setting. We aimed to estimate the global demand for and supply of radiotherapy megavoltage machines (MVMs) and assess the changes in supply and demand during the past decade.

MATERIALS AND METHODS

Cancer incidences for 27 cancer types in 184 countries were extracted from the International Agency for Research on Cancer GLOBOCAN database. The Collaboration for Cancer Outcomes Research and Evaluation radiotherapy utilization rate (RTU) model was used to estimate the number of patients in each country with an indication for radiotherapy for each cancer type and estimate the demand for MVMs. The radiotherapy supply data were accessed from Directory of Radiotherapy Centres database maintained by the International Atomic Energy Agency.

RESULTS

RTU varied by country, from 32% in Mongolia to 59% in Comoros. The average optimal world RTU was 50%, equating to 7 million people in 2012 who would benefit from radiotherapy. There remains a deficit of more than 7,000 machines worldwide. During the past decade, the gap between radiotherapy demand and supply has widened in low-income countries.

CONCLUSION

RTU varies significantly between countries. Approximately half of all patients with cancer worldwide should receive radiotherapy; however, more than 2 million people are unable to access it because of a lack of MVMs. Low- and middle-income countries are particularly disadvantaged by this deficit.

Omission of Breast Radiotherapy in Low-risk Luminal A Breast Cancer: Impact on Health Care Costs

AIMS

The economic burden of cancer care is substantial, including steep increases in costs for breast cancer management. There is mounting evidence that women age ≥ 60 years with grade I/II T1N0 luminal A (ER/PR+, HER2- and Ki67 ≤ 13%) breast cancer have such low local recurrence rates that adjuvant breast radiotherapy might offer limited value. We aimed to determine the total savings to a publicly funded health care system should omission of radiotherapy become standard of care for these patients.

MATERIALS AND METHODS

The number of women aged ≥ 60 years who received adjuvant radiotherapy for T1N0 ER+ HER2- breast cancer in Ontario was obtained from the provincial cancer agency. The cost of adjuvant breast radiotherapy was estimated through activity-based costing from a public payer perspective. The total saving was calculated by multiplying the estimated number of luminal A cases that received radiotherapy by the cost of radiotherapy minus Ki-67 testing.

RESULTS

In 2010, 748 women age ≥ 60 years underwent surgery for pT1N0 ER+ HER2- breast cancer; 539 (72%) underwent adjuvant radiotherapy, of whom 329 were estimated to be grade I/II luminal A subtype. The cost of adjuvant breast radiotherapy per case was estimated at $6135.85; the cost of Ki-67 at $114.71. This translated into an annual saving of about $2.0million if radiotherapy was omitted for all low-risk luminal A breast cancer patients in Ontario and $5.1million across Canada.

CONCLUSION

There will be significant savings to the health care system should omission of radiotherapy become standard practice for women with low-risk luminal A breast cancer.

Expanding global access to radiotherapy

Radiotherapy is a critical and inseparable component of comprehensive cancer treatment and care. For many of the most common cancers in low-income and middle-income countries, radiotherapy is essential for effective treatment. In high-income countries, radiotherapy is used in more than half of all cases of cancer to cure localised disease, palliate symptoms, and control disease in incurable cancers. Yet, in planning and building treatment capacity for cancer, radiotherapy is frequently the last resource to be considered. Consequently, worldwide access to radiotherapy is unacceptably low. We present a new body of evidence that quantifies the worldwide coverage of radiotherapy services by country. We show the shortfall in access to radiotherapy by country and globally for 2015-35 based on current and projected need, and show substantial health and economic benefits to investing in radiotherapy. The cost of scaling up radiotherapy in the nominal model in 2015-35 is US$26·6 billion in low-income countries, $62·6 billion in lower-middle-income countries, and $94·8 billion in upper-middle-income countries, which amounts to $184·0 billion across all low-income and middle-income countries. In the efficiency model the costs were lower: $14·1 billion in low-income, $33·3 billion in lower-middle-income, and $49·4 billion in upper-middle-income countries-a total of $96·8 billion. Scale-up of radiotherapy capacity in 2015-35 from current levels could lead to saving of 26·9 million life-years in low-income and middle-income countries over the lifetime of the patients who received treatment. The economic benefits of investment in radiotherapy are very substantial. Using the nominal cost model could produce a net benefit of $278·1 billion in 2015-35 ($265·2 million in low-income countries, $38·5 billion in lower-middle-income countries, and $239·3 billion in upper-middle-income countries). Investment in the efficiency model would produce in the same period an even greater total benefit of $365·4 billion ($12·8 billion in low-income countries, $67·7 billion in lower-middle-income countries, and $284·7 billion in upper-middle-income countries). The returns, by the human-capital approach, are projected to be less with the nominal cost model, amounting to $16·9 billion in 2015-35 (-$14·9 billion in low-income countries; -$18·7 billion in lower-middle-income countries, and $50·5 billion in upper-middle-income countries). The returns with the efficiency model were projected to be greater, however, amounting to $104·2 billion (-$2·4 billion in low-income countries, $10·7 billion in lower-middle-income countries, and $95·9 billion in upper-middle-income countries). Our results provide compelling evidence that investment in radiotherapy not only enables treatment of large numbers of cancer cases to save lives, but also brings positive economic benefits.

Australian survey on current practices for breast radiotherapy

INTRODUCTION

Detailed, published surveys specific to Australian breast radiotherapy practice were last conducted in 2002. More recent international surveys specific to breast radiotherapy practice include a European survey conducted in 2008/2009 and a Spanish survey conducted in 2009. Radiotherapy techniques continue to evolve, and the utilisation of new techniques, such as intensity-modulated radiation therapy (IMRT), is increasing. This survey aimed to determine current breast radiotherapy practices across Australia.

METHOD

An online survey was completed by 50 of the 69 Australian radiation therapy treatment centres.

RESULTS

Supine tangential beam whole breast irradiation remains the standard of care for breast radiotherapy in Australia. A growing number of institutions are exploring prone positioning and IMRT utilisation. This survey demonstrated a wide variation in the benchmarks used to limit and report organ at risk doses, prescribed dose regimen, and post-mastectomy bolus practices. This survey also indicated, when compared with international literature, that there may be less interest in or uptake of external beam partial breast irradiation, prone positioning, simultaneous integrated boost and breath hold techniques. These are areas where further review and research may be warranted to ensure Australian patients are receiving the best care possible based on the best evidence available.

CONCLUSION

This survey provides insight into the current radiotherapy practice for breast cancer in Australia.

The role of elective para-aortic lymph node irradiation in patients with locally advanced cervical cancer

AIMS

Pelvic lymph node positivity in cervical cancer is known to be an adverse prognostic factor and is associated with an elevated risk of clinically occult para-aortic lymph node metastases. The purpose of this study was to examine the benefit of elective para-aortic lymph node radiotherapy (PART) in patients with no clinical or radiographic evidence of para-aortic lymph node metastases receiving concurrent cisplatin chemotherapy.

MATERIALS AND METHODS

Patients treated with radiotherapy and concurrent cisplatin for cervical cancer from 1999 to 2009 were identified in two prospective databases. All patients received external beam pelvic radiotherapy (PRT) to a median dose of 50 Gy concurrently with weekly cisplatin 40 mg/m(2). This was followed by pulse dose rate intracavitary brachytherapy to a median dose of 40 Gy. Patients at high risk of occult para-aortic metastases also received PART to a median dose of 40 Gy.

RESULTS

There were 228 patients suitable for analysis; the median follow-up was 4.6 years. The addition of PART to PRT was not associated with a significant difference in disease-free survival (hazard ratio 1.1, confidence interval 0.7-1.8, P = 0.75) or overall survival (hazard ratio 1.6, confidence interval 0.9-2.7, P = 0.11) on multivariate analysis. There was no significant difference in the rate of para-aortic relapse with PART versus PRT (hazard ratio 2.01, confidence interval 0.79-5.12, P = 0.14). The 3 year grade 3-4 late toxicities were 11% for the PART group versus 8% for PRT (hazard ratio 1.39, confidence interval 0.58-3.37, P = 0.47).

CONCLUSIONS

These results suggest that cervical cancer patients treated with radiotherapy and concurrent cisplatin do not benefit from elective PART.

Abstract P5-14-01: Chest wall bolus in post-mastectomy radiotherapy – Is it really necessary?

Purpose: The utilization of tissue-equivalent chest wall bolus in post-mastectomy radiotherapy (PMRT) varies significantly between institutions. There is a paucity of clinical evidence to support the need for bolus in this setting. This study reports on clinical outcomes for PMRT patients treated without the routine use of bolus.

Methods and Materials: We included patients who received adjuvant chest wall +/- loco-regional nodal PMRT at a single institution for invasive breast cancer from 2004-2009. Patients received a median PMRT dose of 50Gy, typically delivered over 25 treatments and using an Intensity Modulated Radiotherapy technique. Patient, tumor and outcome data were collected from an established prospective database, with additional radiotherapy and acute toxicity details supplemented retrospectively. The use of chest wall bolus was decided by the treating radiation oncologist, based on features such as clinical or pathological dermal involvement. The bolus used was 5mm thickness and typically administered on alternate days of radiotherapy treatment. Outcomes measured included RTOG acute skin toxicity, loco-regional relapse, distant metastatic relapse, and overall survival (OS). Groups were compared using Gray's test, while hazard ratios were calculated using the Fine and Gray competing risk regression model.

Results: A total of 314 patients were suitable for analysis: 52 received bolus and 262 did not. The median follow up was 4.2 years, with a mean age of 52.7 years. Patients who received bolus had a higher T stage than those without bolus, with T1 tumors 16% vs 26%, T2 tumors 24% vs 40%, T3 tumors 45% vs 27% and T4 tumors 10% vs 1% (p = 0.002). For the whole cohort, 35% had N1 disease and 38% had N2/N3 disease, with no significant differences in N stage between the two groups. There was a higher incidence of dermal invasion for the bolus group compared to non-bolus, 27% vs. 7% (p&lt;0.001), as well as lympho-vascular invasion, 73% vs. 46% (p&lt;0.001) and positive margins, 14% vs. 3% (p = 0.003). There were no significant differences between the 2 groups in terms of ER positivity (58 vs. 76% p = 0.07), HER 2 positivity (17 vs. 9% p = 0.09) or grade 3 disease (75 vs. 67%, p = 0.77). Four-year LRR was 14% in the bolus group and 3% in the non-bolus group. On uni-variate analysis, this resulted in a significant difference in LRR (HR 3.1; CI 1.2-8.3; p = 0.02). However, when adjusting for margin status (HR 5.0; CI 1.5-16.5; p = 0.008), this result was no longer significant (HR = 2.5; CI 0.8-7.5, p = 0.12). Four-year OS was 77% vs. 86% for bolus vs. non-bolus group (p = 0.07). The pattern of failure in this cohort was predominantly distant, with 50/314 patients (16%) developing distant metastases as the first site of failure, 17 patients (5%) in the chest wall and 4 (1%) in regional nodes. There was a significant difference in acute skin toxicity between the bolus vs. non-bolus groups (p = 0.01) with Grade 2 toxicity 37% vs. 21%, grade 3 toxicity 0 vs. 1% and grade 4 toxicity 2% vs. 0%.

Conclusions: In this patient population, the LRR rates without the use of bolus were low and consistent with published reports. These results suggest that in the setting of PMRT, patients without higher risk features such as positive margins or dermal invasion may not require the use of bolus.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-14-01.

Outcomes following treatment for patients with cranial nerve involvement from nasopharyngeal cancer

INTRODUCTION

Patients with locally advanced nasopharyngeal carcinoma (NPC) commonly present with cranial nerve (CN) involvement, which can cause significant morbidity. We aimed to characterise the pattern of involvement and outcomes of these patients, as well as determine if these differed according to the mode of diagnosis.

METHODS

Patients were included if they had non-distant metastatic NPC, presented with CN involvement and completed radiotherapy treatment between 2002 and 2008. The clinical response was categorised as complete response, partial response, stable or progressive disease. The radiological response was assessed using the Response Evaluation Criteria in Solid Tumors criteria. The loco-regional control and disease-free survival rates were estimated with the Kaplan-Meier method.

RESULTS

Forty-seven patients fulfilled the inclusion criteria. CN lesions were diagnosed on clinical examination in 15% of patients, radiologically in 40% and both clinically and radiologically in 45% of patients. A complete or partial response of the CN lesions was seen clinically in 82% and radiologically in 95% of patients. The 3-year local relapse free survival was 64.3%, distant metastasis-free survival was 46.1% and overall survival was 82.8%. There were no differences in outcomes between patients with clinically versus radiologically detected CN lesions.

CONCLUSION

Most of these patients are likely to undergo clinical and/or radiological resolution of the nerve lesions following chemoradiotherapy, but the outcome was not determined by the mode of diagnosis (radiological or clinical).

Prognostic significance of high-risk human papilloma virus (HPV), p16, and p53 status in women with vulvar squamous cell carcinoma (VSCC)

5105

Background: The incidence of VSCC is increasing. Studies suggest the presence of two histologically and molecularly distinct subsets of VSCC; one contingent on and another independent of HPV infection. However, it is uncertain if HPV status has prognostic significance. HPV oncoproteins can result in degradation of the tumor suppressor p53, cell cycle deregulation and abnormal expression of cyclin dependant kinase inhibitor p16. The aim of this study was to investigate HPV infection, p16 and p53 in relation to clinical parameters in women with VSCC. Methods: Sequential cases of VSCC from patients (pts) treated at Princess Margaret Hospital (PMH) from 2000 to 2008 were reviewed. HPV infection was evaluated by Roche Linear array. A tissue microarray was constructed. p16 and p53 immunohistochemistry was performed. Clinical data was abstracted from medical records and PMH Cancer Database. Survival analysis was performed using Kaplan-Meier curves and log rank test. Results: We identified124 pts with VSCC. HPV was detected in 43/123 (35%) pts (median age 71 ± 16 yrs). HPV16 was the most common serotype (38/43; 88.4%). p16 was expressed in 30/115 (26%) pts and p53 in 59/117 (50.4%) pts. Median age of pts was not different in relation to HPV, p16 and p53 status. Expression of p16 (p<0.0001) and loss of p53 (p=0.007) were associated with HPV infection. Pts with HPV positive tumors were less likely to recur (recurrence rate at 5 years (RR) 12.5% vs 50.3%, p=0.009). HPV positive VSCC were not associated with better 5 yr disease free survival (DFS), 58% vs 31%; p=0.15, or overall survival (OS), 61% vs 61% ; p=0.94. p16 positive tumors had a lower RR at 5 yrs, 23.8% vs 59%, p=0.006 and better 5yr DFS (61% vs 27% ; p=0.009) but not significant for OS (65% vs 59%; p=0.94). Among pts with HPV positive VSCC, OS and DFS were not different between p16 positive and negative VSCC. In the 46 pts treated with radiotherapy, HPV and p16 positive tumors were associated with a lower RR (p=0.004 and 0.005). p53 expression was not prognostic in any pt group. Conclusions: Women with HPV-positiveVSCC have a lower risk of disease recurrence. p16-expressing VSCC are associated with reduced disease recurrence and improved DFS.