Prognostic Value of Weekly Delta-Radiomics during MR-Linac Radiotherapy of Glioblastoma

PURPOSE/OBJECTIVE(S)

MRI after chemoradiotherapy (chemoRT) shows areas of presumed tumor growth in ≤ 50% of glioblastoma (GBM) patients, which can be true progression (TP) - tumor growth with poor treatment response, or pseudoprogression (PP) - edema and tumor necrosis with favorable treatment response. Patients with TP have median overall survival (OS) of only 7 months, while patients with PP have median OS of 36 months. However, on imaging, TP and PP are usually not discernible during treatment, making it difficult to adapt radiation for poor responders. The purpose of this study was to investigate the prognostic value of delta radiomic features from MR-Linac for GBM.

MATERIALS/METHODS

Using an IRB-approved prospective cohort of GBM patients undergoing 30 fractions of chemoRT to 60 Gy on a 0.35T MR-Linac, 2 regions of interest (ROI) were contoured on daily T2-weighted treatment set-up scans: 1) tumor/edema (lesion) and 2) post-surgical resection cavity (RC). The lesion ROI were used to calculate texture features: second order radiomics features based on the gray-level co-occurrence matrix (GLCM), gray-level size zone matrix (GLSZM), gray-level run length matrix (GLRLM), and neighborhood gray-tone difference matrix (NGTDM). Each of these describe the probability of spatial relationships of gray levels occurring within the ROI. Features from fraction 1 (pre-radiation) were subtracted from fractions 5, 10, 15, 25, and 30 to create delta features at 5 timepoints (D5-D30). Patient response was retrospectively defined as no progression (NP), TP, or PP. Supervised machine learning was utilized using a 500-tree random forest (RF) classification model with TP or PP as the outcome. Variable importance analysis was conducted by calculating the out-of-bag errors with multiple bootstrapped data sets. The most prognostic features were selected using the RF importance scores.

RESULTS

Thirty-six patients were screened for inclusion: 9 were excluded due to no T2 lesion (RC ROI only). Of the remaining 27 patients: 10 had NP, 11 had TP, and 6 had PP. Thirty-nine texture features, plus lesion volume and mean lesion intensity (for a total of 41 variables per time point) were calculated and included in the model. Of the 10 most prognostic features, 6 were from D10, suggesting that prognostic changes in the underlying lesion microenvironment are occurring within the first 10 fractions of treatment. The model selected GLSZM high gray-level zone emphasis (HGZE) D10, IBSI code 5GN9, as the most prognostic feature. The receiver operator characteristic (ROC) area under the curve (AUC) for GLSZM HGZE D10 was 0.94 (95% CI = 0.81-1.00).

CONCLUSION

Delta radiomic features extracted from MR-Linac imaging may predict between PP and TP in GBM patients during treatment, which is earlier than current methods. This could allow physicians to adapt/intensify treatment in real time for poorly responding patients. Future directions include analysis with a larger patient cohort and with additional MRI contrasts (MR-Linac multiparametric MRI).

Weighted ensemble: Recent mathematical developments

Weighted ensemble (WE) is an enhanced sampling method based on periodically replicating and pruning trajectories generated in parallel. WE has grown increasingly popular for computational biochemistry problems due, in part, to improved hardware and accessible software implementations. Algorithmic and analytical improvements have played an important role, and progress has accelerated in recent years. Here, we discuss and elaborate on the WE method from a mathematical perspective, highlighting recent results that enhance the computational efficiency. The mathematical theory reveals a new strategy for optimizing trajectory management that approaches the best possible variance while generalizing to systems of arbitrary dimension.

System resilience and neighbourhood action on social determinants of health inequalities: an English Case Study

AIMS

This article seeks to make the case for a new approach to understanding and nurturing resilience as a foundation for effective place-based co-produced local action on social and health inequalities.

METHODS

A narrative review of literature on community resilience from a public health perspective was conducted and a new concept of neighbourhood system resilience was developed. This then shaped the development of a practical programme of action research implemented in nine socio-economically disadvantaged neighbourhoods in North West England between 2014 and 2019. This Neighbourhood Resilience Programme (NRP) was evaluated using a mixed-method design comprising: (1) a longitudinal household survey, conducted in each of the Neighbourhoods For Learning (NFLs) and in nine comparator areas in two waves (2015/2016 and 2018/2019) and completed in each phase by approximately 3000 households; (2) reflexive journals kept by the academic team; and (3) semi-structured interviews on perceptions about the impacts of the programme with 41 participants in 2019.

RESULTS

A difference-in-difference analysis of household survey data showed a statistically significant increase of 7.5% (95% confidence interval (CI), 1.6 to 13.5) in the percentage of residents reporting that they felt able to influence local decision-making in the NFLs relative to the residents in comparator areas, but no effect attributable to the NRP in other evaluative measures. The analysis of participant interviews identified beneficial impacts of the NRP in five resilience domains: social connectivity, cultural coherence, local decision-making, economic activity, and the local environment.

CONCLUSION

Our findings support the need for a shift away from interventions that seek solely to enhance the resilience of lay communities to interventions that recognise resilience as a whole systems phenomenon. Systemic approaches to resilience can provide the underpinning foundation for effective co-produced local action on social and health inequalities, but they require intensive relational work by all participating system players.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Long-term outcomes of real world 'watch and wait' data for rectal cancer after neoadjuvant chemoradiotherapy

AIM

A 'watch and wait' (W&W) strategy after neoadjuvant long-course chemoradiotherapy (NACRT) remains controversial. Whilst encouraging short-term data exist, the strategy will be judged on long-term data. We present long-term, real-world UK data from a single National Health Service trust.

METHODS

An analysis was performed of a prospectively maintained W&W database over 9 years between 2010 and 2018. Outcome measures include incidence and time to regrowth and overall and disease-free survival.

RESULTS

We diagnosed 563 rectal cancers in 9 years. In all, 283 patients underwent rectal resection (50.3%). NACRT was used in 155 patients for margin-threatened tumours on staging MRI. Forty-nine patients (31.6%) experienced either a 'near complete' or a complete clinical response (cCR) at their 10 weeks post-NACRT assessment (MRI and endoscopy). The median age was 69 years (range 44-83), and the male to female ratio was 32:17. The median follow-up was 38 months (range 12-96). The median tumour distance from the anal verge was 7 cm (1-15 cm). Twenty-two patients had a cCR on initial assessment and 27 patients had a 'near' cCR. Of those 27 who experienced a 'near' cCR, 17 (63%) progressed to cCR on repeat assessment and 10 (37%) did not. Of these 10 patients, seven underwent standard surgical resection and three were unfit for surgery. R0 for the seven with delayed resection was 100%. Of 39 patients (22 cCR and 17 'near' cCR who progressed to cCR) (25.2% of those receiving NACRT), six patients experienced local regrowth (15.4%). The median time to local regrowth was 29 months (15-60 months). One of these six patients underwent salvage abdominoperineal resection, one was advised to have contact radiotherapy and four opted against surgery and also had contact radiotherapy. The overall survival was 100% at 2 years and 90% at 5 years. Disease-free survival was 90.47% at 2 years and 74.8% at 5 years.

CONCLUSION

A W&W treatment strategy was employed safely in this patient cohort with acceptable rates of local regrowth and survival.

Impact of contouring variability on oncological PET radiomics features in the lung

Radiomics features extracted from oncological PET images are currently under intense scrutiny within the context of risk stratification for a variety of cancers. However, the lack of robustness assessment poses problems for their application across institutions and for broader patient populations. The objective of the current study was to examine the extent to which radiomics parameters from oncological PET vary in response to manual contouring variability in lung cancer. Imaging data employed in the study consisted of 26 PET scans with lesions in the lung being created through the use of an anthropomorphic phantom in conjunction with Monte Carlo simulations. From each of the simulated lesions, 25 radiomics features related to the gray-level co-occurrence matrices (GLCOM), gray-level size zone matrices (GLSZM), and gray-level neighborhood difference matrices (GLNDM) were extracted from ground truth contour and from manual contours provided by 10 raters in regard to four intensity discretization schemes with number of gray levels of 32, 64, 128, and 256, respectively. The impact of interrater variability in tumor delineation upon the agreement between raters on radiomics features was examined via interclass correlation and leave-p-out assessment. Only weak and moderate correlations were found between segmentation accuracy as measured by the Dice coefficient and percent feature error from ground truth for the vast majority of the features being examined. GLNDM-based texture parameters emerged as the top performing category of radiomcs features in terms of robustness against contouring variability for discretization schemes engaging number of gray levels of 32, 64, and 128 while GLCOM-based parameters stood out for discretization scheme engaging 256 gray levels. How and to what extent interrater reliability of radiomics features vary in response to the number of raters were largely feature-dependent. It was concluded that impact of contouring variability on PET-based radiomics features is present to varying degrees and could be experienced as a barrier to convey PET-based radiomics research to clinical relevance.

A prospective observational study testing liquid crystal phase change type thermometer placed on skin against oesophageal/pharyngeal placed thermometers in participants undergoing general anesthesia

Background

Patient outcomes are influenced by intraoperative temperature management. Oesophageal/pharyngeal temperature monitoring is the standard of care at our institute but is not well tolerated in awake patients. Many non-invasive temperature monitors have been studied. Only the TraxIt® Wearable Children’s Underarm Thermometer which contains liquid crystals that undergo phase changes according to temperature is available at our institution. We tested these non-invasive monitors against our standard of care which is the oesophageal/pharyngeal temperature monitor.

Methods

We conducted a prospective observational study of 100 patients receiving general anaesthesia for elective surgery. Patients were eligible for inclusion if they were ≥ 18 years old, were planned to have a general anaesthetic > 60 min during which no body cavity (chest or abdomen) would be opened. Patient temperature was measured with an oesophageal/pharyngeal thermistor probe and skin surface temperature monitors placed over the forehead, in the axilla, over the sternum, and behind the ear (over major vessels to the brain). Temperatures were recorded and then analysed using Altman-Bland plots. Pre-determined clinically relevant limits of agreement were set at −/+ 0.5 °C.

Results

From the 100 patients we collected 500 data points for each monitor with an average monitoring time of 102 min (30–300 min) across a range of surgical procedures. None of the skin surface temperature monitors achieved the pre-determined limits of agreement and results were impacted by the use of a forced air warmer.

Conclusion

The TraxIt® Wearable Children’s Underarm Thermometers are not suitable for temperature monitoring during general anaesthesia.

Multidrug-resistant tuberculosis in Queensland, Australia: an ongoing cross-border challenge

SETTINGp: Multidrug-resistant tuberculosis (MDR-TB) is a growing concern worldwide. In Australia, although the incidence of MDR-TB remains low, Queensland is at an increased risk due to its proximity to Papua New Guinea (PNG).

OBJECTIVE

To examine the epidemiology, clinical features and outcomes of MDR-TB in Queensland, with a comparison between cross-border PNG and non-cross-border patients.

DESIGN

Retrospective case series of all MDR-TB patients in Queensland between 1 January 2000 and 31 December 2014.

RESULTS

Ninety-six patients were diagnosed with MDR-TB in Queensland between 2000 and 2014. The majority were cross-border PNG nationals diagnosed within the Torres Straight Protected Zone (n = 73, 76%). Cross-border patients were younger (27.4 vs. 36.3 years, P = 0.02), had spent less time in Australia before diagnosis (<1 vs. 19 months, P < 0.01), had higher rates of smear positivity (67.1% vs. 40%, P = 0.04) and were less likely to have received a second-line injectable agent (45.8% vs. 71.4%, P = 0.05). Cross-border patients had significantly lower rates of treatment success than non-cross-border patients (47.9% vs. 85.7%; P < 0.01).

CONCLUSION

MDR-TB cases in Queensland are largely a result of cross-border PNG nationals, with poorer outcomes seen in this cohort. Continued strengthening of the region's TB programmes, with a focus on cross-border patients, is required.

Paediatric tuberculosis in Queensland, Australia: overrepresentation of cross-border and Indigenous children

SETTING

Queensland, Australia.

BACKGROUND

Understanding paediatric tuberculosis (TB) is important, as children with TB typically reflect recent community transmission. Children pose unique diagnostic challenges and are at risk of developing severe disseminated infection.

OBJECTIVE

To describe the epidemiology, presentation and outcomes of children with TB disease in Queensland.

DESIGN

This is a retrospective case series of children diagnosed with TB aged 0-16 years notified in 2005-2014. Data collected in the Queensland Notifiable Conditions System were extracted and analysed.

RESULTS

Of 127 children diagnosed with TB, 16 were Australian-born (including 12 Indigenous Queenslanders), 41 were overseas-born permanent and temporary residents and 70 were cross-border Papua New Guinea (PNG) children; 88 children had pulmonary disease (with/without other sites) and 39 had extra-pulmonary disease only, with lymph node TB the predominant extra-pulmonary site; 70.1% of children had laboratory confirmation; and 14 cross-border children had multidrug-resistant TB. Treatment outcomes among children residing in Australia were good (100% among Australian-born and 97.2% among permanent and temporary residents), but they were less favourable among PNG children diagnosed in the Torres Strait Protected Zone (76.6%).

CONCLUSION

Queensland has unique challenges in TB control, with a high proportion of cross-border diagnoses and over-representation of Indigenous children. Vigilance is needed given the wide spectrum of clinical presentation, particularly in high-risk communities.

Excited States and Collectivity in 88Se

The γ decays of excited states in the very neutron-rich nucleus 88Se have been observed following the cold neutron-induced fission of 235U at the PF1B facility of the Institut Laue-Langevin (ILL), Grenoble. The EXILL array was used to measure γ - γ - γ coincidences, which were then analysed to build a level scheme of 88Se. A low (2+1) energy hints at the onset of quadrupole deformation and the identification of possible members of a (2+2) band provide evidence for γ vibrations. Shell-model calculations using a 78Ni core reproduce the experimental decay scheme well, implying that interactions between particles in the π f5/2 p and vsd orbits are responsible for much of the collectivity present. The algebraic collective model has also been used to interpret the experimental data, showing that that the experimental spectrum is consistent with 88Se being a transitional nucleus, possessing weak static β deformation and γ instability.

The role of the neutrophil:lymphocyte ratio (NLR) and the CRP:albumin ratio (CAR) in predicting mortality following emergency laparotomy in the over 80 age group

INTRODUCTION

Emergency laparotomy in the elderly is an increasingly common procedure which carries high morbidity and mortality. Risk prediction tools, although imperfect, can help guide management decisions. Novel markers of surgical outcomes may contribute to these scoring systems. The neutrophil:lymphocyte ratio (NLR) and CRP:albumin ratio (CAR) have been associated with outcomes in malignancy and sepsis. We assessed the use of ratio NLR and CAR as prognostic indicators in patients over the age of 80 undergoing emergency laparotomy.

METHODS

A retrospective analysis of all patients over the age of 80 who underwent emergency laparotomy during a 3 year period was conducted. Pre and post-operative NLR and CAR were assessed in relation to outcome measures including inpatient, 30-day and 90-day mortality. Statistical analysis was conducted with Mann-Whitney U, receiver operating characteristics, Spearmans rank correlation coefficient and chi-squared tests.

RESULTS

One hundred and thirty-six patients over the age of 80 underwent emergency laparotomy. Median age was 84 years (range 80-96 years). Overall inpatient mortality was 19.2%. Pre-operative and post-operative NLR and CAR were significantly raised in patients with sepsis v no sepsis (p < 0.05). Pre-operative NLR was significantly associated with inpatient (p = 0.046), 30-day (p = 0.02) and 90-day mortality (p = 0.01) in patients with visceral perforation. A pre-operative NLR value of greater than 8 was associated with significantly increased mortality (p = 0.016, AUC:0.78). CAR was not associated with mortality.

CONCLUSION

Pre-operative NLR is associated with mortality in patients with visceral perforation undergoing emergency laparotomy. NLR > 8 is associated with a poorer outcome in this group of patients. CAR was not associated with mortality in over-80s undergoing emergency laparotomy.

(97)(37)Rb(60): The Cornerstone of the Region of Deformation around A ∼ 100 [corrected]

Excited states of the neutron-rich nuclei (97,99)Rb were populated for the first time using the multistep Coulomb excitation of radioactive beams. Comparisons of the results with particle-rotor model calculations provide clear identification for the ground-state rotational band of (97)Rb as being built on the πg(9/2) [431] 3/2(+) Nilsson-model configuration. The ground-state excitation spectra of the Rb isotopes show a marked distinction between single-particle-like structures below N=60 and rotational bands above. The present study defines the limits of the deformed region around A∼100 and indicates that the deformation of (97)Rb is essentially the same as that observed well inside the deformed region. It further highlights the power of the Coulomb-excitation technique for obtaining spectroscopic information far from stability. The (99)Rb case demonstrates the challenges of studies with very short-lived postaccelerated radioactive beams.

Characteristics of pain in hospitalized medical patients, surgical patients, and outpatients attending a pain management centre

BACKGROUND

The characteristics and psychological impact of pain suffered by medical inpatients has been relatively under-investigated. The aim of this study was to compare the pain experience of medical, surgical inpatients, and patients attending a pain management centre. Some aspects of the quality of pain scoring and prescribing were also audited.

METHODS

Medical inpatients with significant pain (moderate or severe pain on a verbal rating scale) were assessed using a battery of psychometric questionnaires. Comparator samples of surgical inpatients and patients attending the pain management centre were recruited.

RESULTS

The prevalence of significant pain did not differ between the medical group (n=37) and the surgical group (n=38) (16.7% and 19.9%). Chronic pain was common in the medical group (54%) and the surgical group (50%). There were no differences in psychometric variables between the medical and surgical groups. Clinically significant scores for anxiety and depression (HADS ≥11) were common in all groups (30-38%). There was less concordance between patient-reported pain scores and nurse-recorded pain scores in the medical group than the surgical group and analgesic prescribing differed between the two groups.

CONCLUSIONS

The characteristics of pain in the medical and surgical groups were similar, with high levels of anxiety and depression. The pain management group differed from the inpatient groups, with higher levels of psychopathology and poorer coping. These findings provide some insight into the complex nature of pain in hospital inpatients, and may inform where limited resources should be utilized to provide greatest patient benefit.

Abstract P3-08-04: Impact of CYP3A variation on estrone levels and breast cancer risk

Background: Epidemiological studies provide strong evidence for a role of endogenous sex steroids in the etiology of breast cancer. Our aim was to identify common variants in genes involved in sex steroid synthesis or metabolism that were associated with premenopausal hormone levels and breast cancer risk.

Methods: We measured urinary estrone glucuronide (E1G) and pregnanediol glucuronide (PG) using a protocol specifically developed to account for cyclic variation in hormone levels during the menstrual cycle, plasma sex hormone-binding globulin (SHBG) and androgenic precursors in up to 763 healthy premenopausal women. We genotyped 642 single nucleotide polymorphisms (SNPs) in these women; a single SNP was further tested for association with breast cancer risk in data from 10,551 breast cancer case patients and 17,535 control subjects. All statistical tests were two-sided.

Results: rs10273424 mapping approximately 50kb centromeric to the cytochrome P450 3A (CYP3A) cluster (7q22.1) was associated with a 21.8% reduction in E1G levels (P = 2.7 × 10−9) and a modest reduction in breast cancer risk in cases diagnosed at or before age 50 (OR = 0.91; P = 0.03) but not older cases (odds ratio (OR) = 1.01; P = 0.82). A rare non-synonymous SHBG SNP was associated with reduced plasma SHBG levels.

Conclusions: Genetic variation in non-coding sequences flanking the CYP3A locus contributes to variance in premenopausal E1G levels and breast cancer risk in younger cases. Since CYP3A4, the most predominantly expressed CYP3A gene, is responsible for metabolism of endogenous and exogenous hormones and hormonal agents such as tamoxifen, used in the treatment of breast cancer this association may have wider implications.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-08-04.

Managing patients with gastrostomy tubes in the community: can a dedicated enteral feed dietetic service reduce hospital readmissions?

BACKGROUND/OBJECTIVES

Post-gastrostomy complications range from 8 to 30%. These complications often occur following discharge into the community and may result in hospital readmission. Our unit previously reported a readmission rate of 23% in 6 months. There is a paucity of data evaluating community gastrostomy management. We therefore aimed to evaluate the benefits of a dedicated dietetic home enteral feed (HEF) team.

SUBJECTS/METHODS

Demographic data, gastrostomy complications, readmission rates and HEF team input was prospectively collected from a cohort of discharged gastrostomy patients over a 1-year period and comparisons made with a similar historical cohort.

RESULTS

A total of 371 complications were encountered in 313 gastrostomy patients during this period, with the commonest complication being over-granulated stoma sites (27%). Of these, 227 hospital admissions were avoided because of direct actions taken by the HEF team. Fifty-nine gastrostomy patients were admitted to the hospital, of which only seven (12%) were specifically for gastrostomy-related problems. Introduction of the HEF team significantly reduced gastrostomy-related hospital readmissions from 23 to 2% (P = 0.0001).

CONCLUSION

Although patients with gastrostomies may need attention to a variety of complex medical problems, many encounter problems specifically related to their gastrostomy after discharge. This is the largest prospective study demonstrating how dietitians trained in gastrostomy aftercare may optimize the management of gastrostomy complications and reduce unnecessary hospital readmissions.

Evidence for a smooth onset of deformation in the neutron-rich Kr isotopes

The neutron-rich nuclei 94,96Kr were studied via projectile Coulomb excitation at the REX-ISOLDE facility at CERN. Level energies of the first excited 2(+) states and their absolute E2 transition strengths to the ground state are determined and discussed in the context of the E(2(1)(+)) and B(E2;2(1)(+)→0(1)(+)) systematics of the krypton chain. Contrary to previously published results no sudden onset of deformation is observed. This experimental result is supported by a new proton-neutron interacting boson model calculation based on the constrained Hartree-Fock-Bogoliubov approach using the microscopic Gogny-D1M energy density functional.

Resistance patterns of multidrug-resistant tuberculosis in Western Province, Papua New Guinea

Few data are available on tuberculosis (TB) drug resistance patterns in Papua New Guinea (PNG) due to the lack of facilities for mycobacterial culture. Many patients from the Western Province seek care in Queensland health clinics in the Torres Strait. Since 2000, we have treated 161 TB cases from PNG, of whom 40 proved to have multidrug-resistant TB (MDR-TB; two human immunodeficiency virus positive). Drug susceptibility testing (DST) shows high levels of resistance to other drugs in the MDR-TB cases (streptomycin 93%, ethionamide 87%, ethambutol 18%, pyrazinamide 10%). No extensively drug-resistant TB (XDR-TB) has been identified. MDR-TB seems to be highly prevalent in the Western Province of PNG, and unless treatment is guided by DST, the risk of XDR-TB emerging is high.