Intraoperative adverse events among surgeons in Singapore: a multicentre cross-sectional study on impact and support

BACKGROUND

It is known that many surgeons encounter intraoperative adverse events which can result in Second Victim Syndrome (SVS), with significant detriment to their emotional and physical health. There is, however, a paucity of Asian studies in this space. The present study thus aimed to explore the degree to which the experience of an adverse event is common among surgeons in Singapore, as well as its impact, and factors affecting their responses and perceived support systems.

METHODS

A self-administered survey was sent to surgeons at four large tertiary hospitals. The 42-item questionnaire used a systematic closed and open approach, to assess: Personal experience with intraoperative adverse events, emotional, psychological and physical impact of these events and perceived support systems.

RESULTS

The response rate was 57.5% (n = 196). Most respondents were male (54.8%), between 35 and 44 years old, and holding the senior consultant position. In the past 12 months alone, 68.9% recalled an adverse event. The emotional impact was significant, including sadness (63.1%), guilt (53.1%) and anxiety (45.4%). Speaking to colleagues was the most helpful support source (66.7%) and almost all surgeons did not receive counselling (93.3%), with the majority deeming it unnecessary (72.2%). Notably, 68.1% of the surgeons had positive takeaways, gaining new insight and improving vigilance towards errors. Both gender and surgeon experience did not affect the likelihood of errors and emotional impact, but more experienced surgeons were less likely to have positive takeaways (p = 0.035). Individuals may become advocates for patient safety, while simultaneously championing the cause of psychological support for others.

CONCLUSIONS

Intraoperative adverse events are prevalent and its emotional impact is significant, regardless of the surgeon's experience or gender. While colleagues and peer discussions are a pillar of support, healthcare institutions should do more to address the impact and ensuing consequences.

Adipose-enriched peri-tumoral stroma, in contrast to myofibroblast-enriched stroma, prognosticates poorer survival in breast cancers

Despite our understanding of the genetic basis of intra-tumoral heterogeneity, the role of stromal heterogeneity arising from an altered tumor microenvironment in affecting tumorigenesis is poorly understood. In particular, extensive study on the peri-tumoral stroma in the morphologically normal tissues surrounding the tumor is lacking. Here, we examine the heterogeneity in tumors and peri-tumoral stroma from 8 ER+/PR+/HER2- invasive breast carcinomas, through multi-region transcriptomic profiling by microarray. We describe the regional heterogeneity observed at the intrinsic molecular subtype, pathway enrichment, and cell type composition levels within each tumor and its peri-tumoral region, up to 7 cm from the tumor margins. Moreover, we identify a pro-inflammatory adipose-enriched peri-tumoral subtype which was significantly associated with poorer overall survival in breast cancer patients, in contrast to an adaptive immune cell- and myofibroblast-enriched subtype. These data together suggest that peri-tumoral heterogeneity may be an important determinant of the evolution and treatment of breast cancers.

Encapsulated papillary carcinoma of the breast: An institutional case series and literature review

BACKGROUND

Encapsulated papillary carcinoma of the breast is rare, making difficult diagnosis and resulting in patients undergoing excision biopsy before definitive surgery. Evidence-based guidelines are sparse. We would like to further elucidate the clinicopathological, treatment and survival outcomes.

MATERIALS AND METHODS

54 patients identified, with a median follow up duration of 48 months. Patients' demographics, radiological and clinicopathological characteristics, treatment, adjuvant therapies as well as survival data were analysed.

RESULTS

18 (33.3%) cases were pure EPC, 12 (22.2%) were EPC associated with ductal carcinoma in situ (DCIS) and 24 (44.4%) cases had concurrent invasive ductal carcinoma. EPCs were more likely to present as a solid-cystic mass on sonography (63.8%), regular-shaped (oval or round) (97.9%), lack spiculations (95.7%) and lack suspicious microcalcifications (95.6%). Median tumour size was largest in the EPC with IDC group (18.5 mm). 2 patients developed loco-regional recurrence. Overall survival is good for EPCs of all subtypes.

CONCLUSION

EPC is a rare tumour with excellent prognosis.

Abstract P6-05-21: Quality of Life and Perspectives of Older Adults with Early & Locally Advanced Breast Cancers Undergoing Pre-operative Therapy

Background: Breast cancer (BC) is the commonest diagnosed cancer in Singaporean women. Increasingly, non-metastatic BC are treated aggressively with neoadjuvant therapy (NAT). Early identification and addressing supportive care needs of NAT treated patients is important for effective cancer care whilst maintaining optimal physical, psychological and social function. This project aims to explore the longitudinal trends of quality of life (QOL) of BC patients enrolled in a NAT program. Methods: This was a prospective cohort study of females aged 21 diagnosed with non-metastatic BC, referred to the NAT program at the SingHealth network of acute hospitals. The Functional Assessment of Cancer Therapy-Breast (FACT-B) was used as a health related QOL measure prior to NAT, within 2 months post definitive breast surgery and at 1-year post diagnosis. In older adults (OA) ≥65 years, the Attitude scale, Now vs Later as well as Health Outcome tool were also performed at baseline. Here we report pre-NAT baseline FACT-B and questionnaire results of OA patients recruited into the NAT program between Jun 2020 and Jun 2021. Results: Pre-NAT median FACT-B scores was 117 (IQR 102-126) for the entire cohort (n=119) and 116 (IQR 104-126) for OA (n=22). OA had significantly lower median Social Wellbeing score at baseline compared to patients < 65 years (p=0.01), while Physical, Emotional, and Functional Wellbeing were not significantly different. More than 50% of OA favoured QOL over quantity of life on the Attitude Scale. 68% of patients would rather have QOL now than 1 year later with half expecting their QOL to reduce by 50% in this time period. When the time scale was extended to 5 years, 64% would rather have QOL 5-years from now instead of QOL now with close to 80% expecting their QOL to be lower in 5 years than presently. Of the 4 outcomes, maintaining independence scored the highest, followed by keeping alive, then reducing/eliminating pain and other symptoms. Conclusion: Our study suggests that OA with BC report similar QOL to younger patients at baseline prior to NAT. Majority of OA patients favoured QOL over quantity of life, and viewed the ability to maintain independence as more important than survival prolongation representing their unique attitude towards cancer treatment and outcomes.

Citation Format: Jun Ma, Zewen Zhang, Jasmine Yun Ting Tan, Whee Sze Ong, Sulastri Kamis, Benita Kiat Tee Tan, Veronique Kiak Mien Tan, Ravindran Kanesvaran, Tira Jing Ying Tan. Quality of Life and Perspectives of Older Adults with Early & Locally Advanced Breast Cancers Undergoing Pre-operative Therapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-05-21.

Abstract P6-01-44: Alteration of DNA methylation landscape in breast patients treated with adjuvant chemotherapy

Background Exposure to cytotoxic chemotherapy treatment may alter DNA methylation (DNAm) in treated patients. Methods We performed DNAm analysis in 1,244 and 897 breast cancer patients treated and not treated by adjuvant chemotherapy using the Illumina MethylationEPIC array (1,804 blood, 337 saliva). DNAm changes of 620,095 individual CpGs and 41,581 promoters were evaluated using linear regression models, adjusting for age at diagnosis, ethnicity, years between sample collection and diagnosis and cell-type heterogeneity. Results from datasets normalized separately were combined by meta-analysis (random effects model). Gene set enrichment analyses were conducted to identify key processes or pathways associated with chemotherapy treatment. Results A total of 425 differentially methylated CpGs and 20 promoters were significantly associated with chemotherapy treatment (p< 5e-8). Enriched gene sets among 3,495 chemotherapy-associated promoters (unadjusted p< 0.05, preranked by Z scores) included three suppressed Gene Ontology (GO) terms that survived Bonferroni correction (GO:0002376, immune system process; GO:0009605, response to external stimulus; and GO:1903034: regulation of response to wounding). Using meta-analysis regression coefficients for all promoters as a ranking metric, olfactory transduction (KEGG, hsa04740) was found to be significantly suppressed (unadjusted p=6.38e-06, adjusted p=0.002). Taste transduction (hsa04742, unadjusted p=1.73e-03, adjusted p=0.565) was the next most significantly suppressed pathway. Conclusion The enrichment of imprinted genes within biological processes and pathways suggests a biological mechanism by which chemotherapy treatment could affect immune response, wound healing and changes in the perceptions of smell and taste.

Citation Format: Peh Joo Ho, Alexis Jiaying Khng, Benita Kiat Tee Tan, Ern Yu Tan, Geok hoon Lim, Su-Ming Tan, Veronique Kiak Mien Tan, Elaine Hsuen Lim, Mikael Hartman, Jingmei Li. Alteration of DNA methylation landscape in breast patients treated with adjuvant chemotherapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-01-44.

Abstract P4-07-49: Neoadjuvant therapy in Asian breast cancer patients with early & locally advanced breast cancers – A contemporary experience from a large tertiary hospital in Singapore

Background: Non-metastatic breast cancers (BC) are increasing treated with neoadjuvant therapy (NAT). Complete pathological response (pCR) is associated with improved survival. Early identification of care needs during NAT is crucial. We report our institution’s experience with NAT. Methods: A prospectively recruited cohort diagnosed with BC, referred to NAT program at SingHealth acute hospitals between June 2020 and June 2021. Demographics, clinical data, pCR (absence of invasive carcinoma in breast and axilla), and Functional Assessment of Cancer Therapy Breast (FACT-B) as quality of life (QOL) measure were collected. Definition of young BC (YBC) were ≤40 years, older adults (OA) ≥65 years. Results: Among 119 eligible patients, 7 (6%) were clinically stage 1, 71 (60%) stage 2, and 41 (35%) stage 3. Twenty-eight (24%) were triple negative (TNBC; defined as HER2- hormonal receptor 0-10% [HR-]), 26 (22%) HER2+ HR-, 45 (38%) HER2+ HR+, 20 (17%) HER2- HR+. Among 71 HER2+ BC, two-thirds received anthracycline (A) based chemotherapy, a quarter A-sparing and remaining 9% taxane only. Majority (89%) received dual HER2 blockade. Among TNBC, 28 (71%) received additional platinum and 2 (7%) immunotherapy. Majority (77%; n=92) completed NAT. Toxicity was main reason for incompletion. Three patients did not undergo surgery: 1 defaulted, 1 demised and the last patient’s surgery was not due at analysis. Of the 116 who underwent surgery, 23 (20%) had breast conservation and 93 (80%) mastectomy. Forty-nine (42%) achieved pCR - 12 (43%) TNBC, 17 (65%) HER2+ HR-, 20 (44%) HER2+ HR+ and 0 in HER2- HR+ (p < 0.001). The pCR rates were also lower by increasing age (Multivariable OR 0.93; 95% CI, 0.90-0.97). Baseline median FACT-B scores was 117 (IQR 102-126) for the cohort: 108 for YBC, 116 for OA and 120 for the rest (p=0.200). At baseline, median score was 28, 24, 18, 22 and 27 in physical, social, emotional, functional wellbeing and BC subscale, respectively, and YBC and OA patients had lower social wellbeing scores than the remaining cohort (22 vs 24, p=0.011). Conclusion: Highest pCR were observed with HER2+ followed by TNBC. Pre-operatively, FACT-B scores were comparable by demographics, staging and tumor subtypes. However, care must be paid to social wellbeing for women in age extremes undergoing NAT.

Citation Format: Zewen Zhang, Jun Ma, Jasmine Yun Ting Tan, Whee Sze Ong, Sulastri Kamis, Grace Yang, Benita Kiat Tee Tan, Veronique Kiak Mien Tan, Tira J. Tan. Neoadjuvant therapy in Asian breast cancer patients with early & locally advanced breast cancers – A contemporary experience from a large tertiary hospital in Singapore [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-49.

Mammography screening is associated with more favourable breast cancer tumour characteristics and better overall survival: case-only analysis of 3739 Asian breast cancer patients

BACKGROUND

Early detection of breast cancer (BC) through mammography screening (MAM) is known to reduce mortality. We examined the differential effect that mammography has on BC characteristics and overall survival and the sociodemographic determinants of MAM utilization in a multi-ethnic Asian population.

METHODS

This study included 3739 BC patients from the Singapore Breast Cancer Cohort (2010-2018). Self-reported sociodemographic characteristics were collected using a structured questionnaire. Clinical data were obtained through medical records. Patients were classified as screeners (last screening mammogram ≤ 2 years before diagnosis), non-screeners (aware but did not attend or last screen > 2years), and those unaware of MAM. Associations between MAM behaviour (MB) and sociodemographic factors and MB and tumour characteristics were examined using multinomial regression. Ten-year overall survival was modelled using Cox regression.

RESULTS

Patients unaware of screening were more likely diagnosed with late stage (OR_{stage III vs stage I (Ref)} [95% CI]: 4.94 [3.45-7.07], p < 0.001), high grade (OR_{poorly vs well-differentiated (reference)}: 1.53 [1.06-2.20], p = 0.022), nodal-positive, large size (OR_{>5cm vs ≤2cm (reference)}: 5.06 [3.10-8.25], p < 0.001), and HER2-positive tumours (OR_{HER2-negative vs HER2-positive (reference)}: 0.72 [0.53-0.97], p = 0.028). Similar trends were observed between screeners and non-screeners with smaller effect sizes. Overall survival was significantly shorter than screeners in the both groups (HR_{non-screeners}: 1.89 [1.22-2.94], p = 0.005; HR_unaware: 2.90 [1.69-4.98], p < 0.001). Non-screeners and those unaware were less health conscious, older, of Malay ethnicity, less highly educated, of lower socioeconomic status, more frequently ever smokers, and less physically active. Among screeners, there were more reported personal histories of benign breast surgeries or gynaecological conditions and positive family history of breast cancer.

CONCLUSIONS

Mammography attendance is associated with more favourable BC characteristics and overall survival. Disparities in the utility of MAM services suggest that different strategies may be needed to improve MAM uptake.

Mammography screening is associated with more favorable breast cancer tumor characteristics and better overall survival: Case-only analysis of 3,739 Asian breast cancer patients

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Background: Early detection of breast cancer (BC) through mammography screening (MAM) is known to reduce mortality. We examined the differential effect that mammography has on BC characteristics and overall survival and the sociodemographic determinants of MAM utilisation in a multi-ethnic Asian population. Methods: This study included 3,739 BC patients from the Singapore Breast Cancer Cohort (2010–2018). Self-reported socio-demographic characteristics were collected using a structured questionnaire. Clinical data were obtained through medical records. Patients were classified as screeners (last screening mammogram ≤two years before diagnosis), non-screeners (aware but did not attend or last screen > 2years) and those unaware of MAM. Associations between MAM behaviour (MB) and sociodemographic factors and MB and tumour characteristics were examined using multinomial regression. Ten-year overall survival was modelled using Cox regression. Results: Patients unaware of screening were more likely diagnosed with late stage (ORstage III vs stage I(Ref) [95%CI]:4.94[3.45-7.07], p < 0.001), high grade (ORpoorly- vs well-differentiated(reference): 1.53 [1.06-2.20], p = 0.022), nodal-positive, large size (OR> 5cm vs ≤2cm(reference): 5.06 [3.10-8.25], p < 0.001), and HER2-positive tumors (ORHER2-negative VS -positive(reference): 0.72[0.53-0.97], p = 0.028). Similar trends were observed between screeners and non-screeners with smaller effect sizes. Overall survival was significantly shorter than screeners in the both groups(non-screeners HR: 1.89 [1.22-2.94], p = 0.005; unaware HR: 2.90[1.69-4.98], p < 0.001). Non-screeners and those unaware were less health-conscious, older, of Malay ethnicity, less highly educated, of lower socioeconomic status, more frequently ever smokers and less physically active. Among screeners, there were more reported personal histories of benign breast surgeries or gynaecological conditions and positive family history of breast cancer. Conclusions: Mammography attendance is associated with more favourable BC characteristics and overall survival. Disparities in the utility of MAM services suggest that different strategies may be needed to improve MAM uptake.

Male breast cancer: a Singapore perspective

INTRODUCTION

Male breast cancer (MBC) is rare, representing <1% of all breast cancers. Treatment recommendations have been extrapolated from trial data of female breast cancer patients. This study aims to report our institutional experience of MBC across a 20 year period, analyse the survival outcome and prognosis of this group against female breast cancer patients treated at the same centre.

METHODS

Clinical, histopathological, treatment and survival data of male and female breast cancer patients treated between Jan 1999 and July 2019 at Singapore General Hospital and National Cancer Centre Singapore were identified and analysed.

RESULTS

Fifty-seven male patients were identified. The median age at diagnosis was 63 years. Majority had invasive ductal carcinoma (86%) and presented at an early disease stage: 70.2% presented as Tis/T1/T2 and 49.1% had no axillary nodal involvement. 84.2% had a simple mastectomy with either a sentinel lymph node biopsy or axillary clearance. The median follow up was 5.69 years for males and 5.83 years for females. The median survival was 11.86 years for males and 16.3 years for females. At 5 years, overall survival (OS) was 69.9% (52.3-82.1%) and disease free survival (DFS) was 62.9% (44.9-76.5%) for males compared with OS 83.8% (83.21-84.39%) and DFS 74.5% (73.91-75.09%) for females.

CONCLUSION

MBC remains understudied. Our institutional data indicates that good long term survival in South-East Asian patients can be achieved with treatment protocols that are similar to female breast cancer. More prospective studies are required.

Polygenic risk scores for prediction of breast cancer risk in Asian populations

PURPOSE

Non-European populations are under-represented in genetics studies, hindering clinical implementation of breast cancer polygenic risk scores (PRSs). We aimed to develop PRSs using the largest available studies of Asian ancestry and to assess the transferability of PRS across ethnic subgroups.

METHODS

The development data set comprised 138,309 women from 17 case-control studies. PRSs were generated using a clumping and thresholding method, lasso penalized regression, an Empirical Bayes approach, a Bayesian polygenic prediction approach, or linear combinations of multiple PRSs. These PRSs were evaluated in 89,898 women from 3 prospective studies (1592 incident cases).

RESULTS

The best performing PRS (genome-wide set of single-nucleotide variations [formerly single-nucleotide polymorphism]) had a hazard ratio per unit SD of 1.62 (95% CI = 1.46-1.80) and an area under the receiver operating curve of 0.635 (95% CI = 0.622-0.649). Combined Asian and European PRSs (333 single-nucleotide variations) had a hazard ratio per SD of 1.53 (95% CI = 1.37-1.71) and an area under the receiver operating curve of 0.621 (95% CI = 0.608-0.635). The distribution of the latter PRS was different across ethnic subgroups, confirming the importance of population-specific calibration for valid estimation of breast cancer risk.

CONCLUSION

PRSs developed in this study, from association data from multiple ancestries, can enhance risk stratification for women of Asian ancestry.

Atypical Ductal Hyperplasia of the Breast on Core Needle Biopsy: Risk of Malignant Upgrade On Surgical Excision

Purpose

This study identified factors predicting malignant upgrade for atypical ductal hyperplasia (ADH) diagnosed on core-needle biopsy (CNB) and developed a nomogram to facilitate evidence-based decision making.

Methods

This retrospective analysis included women diagnosed with ADH at the National Cancer Centre Singapore (NCCS) in 2010–2015. Cox proportional hazards regression was used to identify clinical, radiological, and histological factors associated with malignant upgrade. A nomogram was constructed using variables with the strongest associations in multivariate analysis. Multivariable logistic regression coefficients were used to estimate the predicted probability of upgrade for each factor combination.

Results

Between 2010 and 2015, 238,122 women underwent mammographic screening under the National Breast Cancer Screening Program. Among 29,564 women recalled, 5,971 CNBs were performed. Of these, 2,876 underwent CNBs at NCCS, with 88 patients (90 lesions) diagnosed with ADH and 26 lesions upgraded to breast malignancy on excision biopsy. In univariate analysis, factors associated with malignant upgrade were the presence of a mass on ultrasound (p = 0.018) or mammography (p = 0.026), microcalcifications (p = 0.047), diffuse microcalcification distribution (p = 0.034), mammographic parenchymal density (p = 0.008). and ≥ 3 separate ADH foci found on biopsy (p = 0.024). Mammographic parenchymal density (hazard ratio [HR], 0.04; 95% confidence interval [CI], 0.005–0.35; p = 0.014), presence of a mass on ultrasound (HR, 10.50; 95% CI, 9.21–25.2; p = 0.010), and number of ADH foci (HR, 1.877; 95% CI, 1.831–1.920; p = 0.002) remained significant in multivariate analysis and were included in the nomogram.

Conclusion

Our model provided good discrimination of breast cancer risk prediction (C-statistic of 0.81; 95% CI, 0.74–0.88) and selected for a subset of women at low risk (2.1%) of malignant upgrade, who may avoid surgical excision following a CNB diagnosis of ADH.

Outcomes of Stage I and II Breast Cancer with Nodal Micrometastases Treated with Mastectomy without Axillary Therapy

PURPOSE

Studies that report equivalent oncologic outcomes of sentinel lymph node biopsy (SLNB) alone versus axillary lymph node dissection (ALND) for T1-2N1mi breast cancers are heavily weighted with patients who received breast-conserving surgery (BCS). The impact of omitting ALND in N1mi patients treated with mastectomy is not well studied. It is also unknown if these patients would benefit from post-mastectomy radiotherapy (PMRT). This study reports the outcomes of patients with T1-2N1mi breast cancer treated by mastectomy without axillary therapy.

METHODS

Patients who had T1-2N1mi breast cancer and underwent mastectomy from January 1998 to December 2018 were identified from our multi-institutional prospective database. Axillary recurrence rate (ARR), disease-free survival (DFS), and overall survival (OS) are reported.

RESULTS

260 patients with pT1-2N1mi breast cancer who had mastectomy were identified. They had either SLNB (35.4%) or ALND (64.6%). Majority of these patients received adjuvant systemic therapy (93.8%). 77 (29.6%) patients received radiotherapy, 31 after SLNB and 46 after ALND. At median follow-up of 61 months, ARR was 1.1% (n = 1) in the SLNB only group, vs. 0.6% (n = 1) in the ALND group (p = 0.752). DFS and OS were not significantly different between patients with SLNB alone versus ALND (p = 0.40 and p = 0.27, respectively). Among 92 patients who had SLNB only, no DFS or OS difference was observed with the use of PMRT.

CONCLUSION

In T1-2N1mi patients with mastectomy and SLNB, axillary recurrences were rare. No statistically significant differences were noted between patients with SLNB, ALND, or PMRT. Our findings suggest that these patients may be safely treated without axillary therapy.

Genetic differences between benign phyllodes tumors and fibroadenomas revealed through targeted next generation sequencing

Breast fibroepithelial lesions are biphasic tumors which comprise the common benign fibroadenomas (FAs) and the rarer phyllodes tumors (PTs). This study analyzed 262 (42%) conventional FAs, 45 (7%) cellular FAs, and 321 (51%) benign PTs contributed by the International Fibroepithelial Consortium, using a previously curated 16 gene panel. Benign PTs were found to possess a higher number of mutations, and higher rates of cancer driver gene alterations than both groups of FAs, in particular MED12, TERT promoter, RARA, FLNA, SETD2, RB1, and EGFR. Cases with MED12 mutations were also more likely to have TERT promoter, RARA, SETD2, and EGFR. There were no significant differences detected between conventional FAs and cellular FAs, except for PIK3CA and MAP3K1. TERT promoter alterations were most optimal in discriminating between FAs and benign PTs. Our study affirms the role of sequencing and key mutations that may assist in refining diagnoses of these lesions.

Study protocol: a pilot quasi-experimental trial of tele-rehabilitation and tele-drain care post-mastectomy

Background

Breast cancer is the leading cancer affecting women in Singapore. Its survivors commonly experience decline in physical function and quality of life post-mastectomy, due to their upper limb morbidity and wound issues. Rehabilitation can address the aforementioned issues. When rehabilitation is accessible and easy to adhere, it can optimize recovery.

Home-based tele-rehabilitation guided by healthcare professionals and self-managed by patients can potentially optimize the patients’ adherence to rehabilitation and recovery. With that in mind, a team of breast cancer specialists (oncologists, nurses, and therapists) in Singapore has developed one of the first tele-rehabilitation systems for local women undergoing a unilateral mastectomy. To our knowledge, no such systems have been evaluated or proven effective as a treatment option among local breast cancer patients with acute disabilities.

Methods

This is a pilot quasi-experimental trial that aims to evaluate the feasibility of tele-rehabilitation and tele-drain care compared to usual care. Up to 40 patients (20 per group) will be recruited for this trial. They will be assigned to an intervention group that receives rehabilitation via a tele-rehabilitation system or a control group that receives rehabilitation in person at their clinic. The primary outcome of this trial is rehabilitation participation (i.e., the time spent on rehabilitation). The secondary outcomes are upper extremity functioning, perceived health, and quality of life.

Discussion

As part of this pilot trial, patients who opt in for the tele-rehabilitation will be asked to share their experience with and thoughts on the tele-rehabilitation system. With the evidence obtained from the tele-rehabilitation patients of this trial, we will be able to improve the current system for our future trial. Further, our additional data on rehabilitation participation, physical function, and quality of life will help us design a sufficiently powered future main trial.

Trial registration

The trial was approved by the National Healthcare Group’s Domain Specific Review Board (#2019/00283) and registered with www.ClinicalTrials.gov (#NCT04269967) in February 2020.

Effects of housing value and medical subsidy on treatment and outcomes of breast cancer patients in Singapore: A retrospective cohort study

Background

Socioeconomic status (SES) is likely to affect survival in breast cancer patients. Housing value is a reasonable surrogate for SES in Singapore where most residents own their own homes, which could be public (subsidised) or private housing. We evaluated effects of housing value and enhanced medical subsidies on patients’ presentation, treatment choices, compliance and survival in a setting of good access to healthcare.

Methods

A retrospective analysis of breast cancer patients treated in a tertiary hospital cluster from 2000 to 2016 was performed. Individual-level Housing value Index (HI) was derived from each patient's address and then grouped into 3 tiers: HI(high)(minimal subsidy), HI(med)(medium subsidy) and HI(low)(high subsidy). Cox regression was performed to evaluate the associations between overall survival (OS) and cancer-specific survival (CSS) with HI and various factors.

Findings

We studied a multiracial cohort of 15,532 Stage 0–IV breast cancer patients. Median age was 53.7 years and median follow-up was 7.7 years. Patients with lower HI presented with more advanced disease and had lower treatment compliance. On multivariable analysis, compared to HI(high) patients, HI(med) patients had decreased OS (HR=1.14, 95% CI 1.05–1.23) and CSS (HR=1.15, 95% CI 1.03–1.27), and HI(low) patients demonstrated reduced OS (HR=1.16, 95% CI 1.01–1.33). Ten-year non-cancer mortality was higher in lower HI-strata. Enhanced medical subsidy approximately halved treatment noncompliance rates but its receipt was not an independent prognostic factor for survival.

Interpretation

Despite good healthcare access, lower-HI patients have poorer survival from both cancer and non-cancer causes, possibly due to delayed health-seeking and poorer treatment compliance. Enhanced subsidies may mitigate socioeconomic disadvantages.

Funding

None.

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale1-3. Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter4; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation5,6; analyses timings and patterns of tumour evolution7; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity8,9; and evaluates a range of more-specialized features of cancer genomes8,10-18.

A novel genomic panel as an adjunctive diagnostic tool for the characterization and profiling of breast Fibroepithelial lesions

Background

Known collectively as breast fibroepithelial lesions (FELs), the common fibroadenomas (FAs) and the rarer phyllodes tumors (PTs) are a heterogenous group of biphasic neoplasms. Owing to limited tissue availability, inter-observer variability, overlapping histological features and heterogeneity of these lesions, diagnosing them accurately on core biopsies is challenging. As the choice management option depends on the histological diagnosis; a novel 16-gene panel assay was developed to improve the accuracy of preoperative diagnosis on core biopsy specimens.

Methods

Using this 16-gene panel, targeted amplicon-based sequencing was performed on 275 formalin-fixed, paraffin-embedded (FFPE) breast FEL specimens, archived at the Singapore General Hospital, from 2008 to 2012.

Results

In total, 167 FAs, 24 benign, 14 borderline and 6 malignant PTs, were profiled. Compared to FAs, PTs had significantly higher mutation rates in the TERT promoter (p <  0.001), RARA (p <  0.001), FLNA, RB1 and TP53 (p = 0.002, 0.020 and 0.018, respectively). In addition to a higher mutational count (p <  0.001), TERT promoter (p <  0.001), frameshift, nonsense and splice site (p = 0.001, < 0.001 and 0.043, respectively) mutations were also frequently observed in PTs.

A multivariate logistic regression model was built using these as variables and a predictive scoring system was developed. It classifies a FEL at low or high risk (score <  1 and ≥ 1, respectively) of being a PT. This scoring system has good discrimination (ROC area = 0.773, 95% CI: 0.70 to 0.85), calibration (p = 0.945) and is significant in predicting PTs (p <  0.001).

Conclusion

This novel study demonstrates the ability to extract DNA of sufficient quality and quantity for targeted sequencing from FFPE breast core biopsy specimens, along with their successful characterization and profiling using our customized 16-gene panel. Prospective work includes validating the utility of this promising 16-gene panel assay as an adjunctive diagnostic tool in clinical practice.

Trends in Post-Mastectomy Reconstruction in an Asian Population: A 12-Year Institutional Review

Post-mastectomy breast reconstruction is an integral component of breast cancer treatment. It is often perceived that women in Asian countries have a lower rate of post-mastectomy reconstruction than Western populations. This study describes trends in timing and types of breast reconstruction performed in the largest healthcare provider in Singapore, over a period of 12 years. It also reports on the oncological outcomes and surgical safety. A retrospective review of all patients who underwent post-mastectomy reconstruction from January 2001 to December 2012 at the National Cancer Centre Singapore and Singapore General Hospital was performed. Six hundred and twenty post-mastectomy reconstructions were performed in 579 patients. The proportion of reconstructions increased from 4% in 2001 to 18% in 2012. Younger patients (<50 years old) and those with early stage cancer were more likely to undergo reconstruction. Immediate breast reconstruction was favored by more than 90% of patients. Postoperatively, 9% developed acute surgical complications that were treated surgically; 6% had additional surgery for late complications. Only 4% had delay of adjuvant chemotherapy. At median follow-up of 63 months (range 3-166), loco-regional recurrence was 4%, and distant metastases 8%. Post-mastectomy reconstruction for breast cancer is increasingly performed in our institution. Both younger age and lower stage disease were associated with choice for reconstruction in our study. Low rates of delay to adjuvant therapy were noted, and it may safely be offered to suitable women undergoing mastectomy.

Landscape of somatic mutations in 560 breast cancer whole-genome sequences

We analysed whole-genome sequences of 560 breast cancers to advance understanding of the driver mutations conferring clonal advantage and the mutational processes generating somatic mutations. We found that 93 protein-coding cancer genes carried probable driver mutations. Some non-coding regions exhibited high mutation frequencies, but most have distinctive structural features probably causing elevated mutation rates and do not contain driver mutations. Mutational signature analysis was extended to genome rearrangements and revealed twelve base substitution and six rearrangement signatures. Three rearrangement signatures, characterized by tandem duplications or deletions, appear associated with defective homologous-recombination-based DNA repair: one with deficient BRCA1 function, another with deficient BRCA1 or BRCA2 function, the cause of the third is unknown. This analysis of all classes of somatic mutation across exons, introns and intergenic regions highlights the repertoire of cancer genes and mutational processes operating, and progresses towards a comprehensive account of the somatic genetic basis of breast cancer.

Sarcoma of the breast: an update on a rare entity

Breast sarcoma is a rare condition. It consists of a heterogeneous group of non-epithelial tumours arising from the mesenchymal tissue of the breast. It has a distinctly different natural history, treatment response and prognosis as compared with carcinoma of the breast. A different diagnostic approach and treatment strategy have to be defined for this group of tumours. Due to its rarity, the current understanding on breast sarcoma is limited and is mostly based on small retrospective case series or case reports. Hence, the management generally follows the algorithms derived from randomised control trials of soft tissue sarcomas in the extremities and chest wall. Through this review, we discuss the results of major retrospective studies on breast sarcomas including data on epidemiology, aetiology, diagnostic approach, treatment strategies and outcomes of this challenging and potentially aggressive condition.

Breast carcinoma and phyllodes tumour: a case series

Malignant transformation of the epithelial component of phyllodes tumours (PT) is rare and only reported in literature as sporadic cases of carcinoma associated with PTs. We report the clinicopathological characteristics of in situ and invasive carcinoma coexisting with PT in 10 patients treated in our institution over an 11-year period from 1992 to 2012. Ten patients with coexisting PT and in situ or invasive carcinoma were identified from our records. Six had carcinoma found within the PT. All were female with a median age of 47 (43-72) years. One patient had a history of PT in the same breast while another had a history of PT in the same breast as well as invasive ductal carcinoma in the contralateral breast. The rest did not have any risk factors of breast cancer. Five patients had a preoperative core needle biopsy performed with the report of a fibroepithelial lesion. The rest of the patients had surgery upfront for their breast masses. Two patients who had ER/PR positive invasive carcinoma received adjuvant hormonal therapy. Patients were followed up for a mean of 3.6 years (9 months-10 years) and all patients were alive and recurrence free. PT associated with carcinoma is rare, and we present a series of cases that add to the limited current literature. It is often difficult to detect the presence of the carcinomatous component preoperatively. Hence, close examination of resected PT specimens must be carried out to allow prompt detection of any associated carcinomas, however rare, such that adequate treatment can be given.

Characteristics and behaviour of screen-detected ductal carcinoma in situ of the breast: comparison with symptomatic patients

Breast cancer is the most common malignancy in Singapore women. Ductal carcinoma in situ (DCIS) is the putative, non-obligate precursor of the majority of invasive breast cancers. The efficacy of the Singapore breast-screening pilot project in detecting early stage breast cancer led to the launch of a national breast-screening programme, BreastScreen Singapore (BSS), in January 2002. In this study, we compared clinicopathological and immunohistochemical characteristics, as well as clinical outcomes, between screen-detected and symptomatic DCIS. The study cohort comprised 1202 cases of DCIS diagnosed at Singapore General Hospital from 1994 to 2010. Comparison of clinicopathological parameters, immunohistochemical results of ER, PR, HER2, CK14, EGFR, and 34βE12, and clinical outcomes was carried out between the 2 groups. Amongst 1202 cases, 610 (50.7%) were screen-detected and 592 (49.3%) were symptomatic DCIS. Screen-detected cases were smaller in size (P < 0.001), of lower nuclear grade (P = 0.004), and more frequently expressed ER (P < 0.001). Luminal A phenotype was more frequently observed in screen-detected DCIS, while triple-negative and HER2 phenotypes were more common in symptomatic DCIS (P < 0.001). The basal-like phenotype was also more frequent in symptomatic DCIS (P = 0.041). Mean and median follow-up was 99.7 and 97.8 months, respectively, with a maximum follow-up of 246.0 months. More symptomatic patients developed invasive recurrences compared to screen-detected patients (P = 0.001). A trend for better disease-free survival was observed in screen-detected patients (P = 0.076). Patients who were screen-detected experienced better overall survival than those with symptomatic DCIS (P = 0.007). Our data indicate a more favourable outcome of screen-detected DCIS patients confirming the role of BSS in early identification of this curable disease.

False negative rate for intraoperative sentinel lymph node frozen section in patients with breast cancer: a retrospective analysis of patients in a single Asian institution

BACKGROUND AND OBJECTIVE

Intraoperative frozen section of the sentinel lymph node (SLN) in clinically node negative breast cancer patients detects metastatic disease and enables axillary lymph node dissection to be performed in the same operative setting. Internationally, the false negative rate (FNR) for SLN biopsy ranges from 5.5% to 43%. The size of SLN metastasis has been identified as a key factor affecting FNR. We review our institutional experience on the accuracy of intraoperative SLN biopsy.

METHODS

Data were collected retrospectively from patients undergoing SLN biopsy performed at Singapore General Hospital. The SLN was identified using blue dye, radioisotope or both. Frozen section was performed intraoperatively. When SLN was positive for metastasis on frozen section, completion axillary clearance was performed. False negative cases were defined as patients in whom a negative frozen section result was obtained, whose final permanent paraffin section was positive. We determined the FNR of SLN frozen section and evaluated the factors associated with it.

RESULTS

A total of 2202 SLN biopsies were performed between January 2005 and June 2012. There were 89 false negative cases, of which there were 23 (25.8%) cases of isolated tumour cells (ITCs), 49 (55.1%) cases of micrometastasis, and 17 (19.1%) cases of macrometastasis. The overall FNR was 13.5%. FNR was 79.3% in ITCs, 59.8% in micrometastasis, and 3.1% in macrometastatic disease. Non-ductal histological subtype, absence of lymphovascular invasion and the size of SLN metastasis were identified as significant independent factors associated with a higher FNR.

CONCLUSIONS

FNRin our institution is acceptable when compared to other large centres. Failure to detect metastasis in frozen section in more than half of our patients was due to ITCs and micrometastasis.

Assessment of suitability of the one step nucleic acid amplification (OSNA) assay as an intraoperative procedure for detection of metastasis in sentinel lymph nodes of breast cancer

AIM

We aimed to assess the one step nucleic acid amplification (OSNA) assay as an intraoperative method in comparison with frozen sections (FS) for detection of metastasis in sentinel lymph nodes (SLNs) of breast cancer.

METHOD

100 SLNs from patients with breast carcinoma were enrolled within a 3-month period. Alternate 2 mm node slices were subjected to routine FS, and later to permanent histology, and the rest for automated molecular detection of CK19 mRNA using OSNA. FS and OSNA findings were compared with permanent histology results. Difference in turnaround time was also noted.

RESULTS

With permanent histology as gold standard, OSNA was discrepant in 8 of 98 (3 false negative, 5 false positive) included SLNs whereas FS had 2 false negative cases. FS had higher sensitivity (89%, p=<0.001), specificity (100%, p=0.001) and concordance rate (98%) than OSNA (83%, 94% and 92%, respectively). FS showed almost perfect agreement (κ=0.929) whereas OSNA showed substantial agreement (κ=0.740) when compared with permanent histology. OSNA turnaround time was twice longer (mean of 47.7 min) than FS.

CONCLUSIONS

Automation of SLN assessment using OSNA is a potentially useful intraoperative diagnostic tool with acceptable accuracy. Discordant findings in this study may be due to sampling allocation. Since OSNA is more time-consuming, its practical advantage over routine FS requires further study in view of current technical workflow considerations.

Contralateral prophylactic mastectomy in an Asian population: a single institution review

BACKGROUND

Contralateral prophylactic mastectomy (CPM) removes the non-diseased breast in women who have unilateral breast cancer. This reduces the incidence of contralateral breast cancer, and potentially improves survival in high risk patients. Such surgical risk-reduction strategy is increasingly being adopted in the United States, despite a decreasing incidence of contralateral breast cancer. The use of CPM in an Asian population is yet unknown. We present the first Asian report on CPM rates and trends in Singapore, the country with the highest incidence of breast cancer in Asia.

METHODS

A retrospective review of all patients who had breast cancer surgery from 2001 to 2010 at the largest healthcare system in Singapore was performed. Patient demographics and tumour characteristics were analysed with regards to type of surgery performed. Factors associated with CPM were identified.

RESULTS

From 2001 to 2010, a total of 5130 patients underwent oncological breast surgery. A decreasing trend of mastectomies (82.7%-70.8%), an upward trend of breast conserving surgery (BCS) (17.3%-29.2%) and an increasing trend in CPM (0.46%-1.25%) is observed. Patients who opted for CPM are likely to be younger (48.4 ± 9.4 years), married (60%), parous (56.7%), with no family history of breast/ovarian cancer (66.7%), and diagnosed at an earlier stage. The rate of synchronous occult breast malignancy was found to be 10% (n = 30), and these were in patients who were of a low cancer-risk profile.

CONCLUSIONS

This retrospective study reflects an increasing incidence of breast cancer in Singapore, with a decrease in mastectomies, and an increase in BCS and CPM rates, similar to Western data. Similar to Western populations, the Asian woman who opts for CPM is likely to be young and have an earlier stage of breast cancer. In contrast, the Asian woman is likely to have no family history of breast or ovarian cancers. Commonly cited reasons for increased CPM rates such as the increased availability of genetic counselling and pre-operative MRI evaluation, along with wide use of reconstruction, do not feature as dominant factors in our population, suggesting that the Asian patients may have different considerations when electing for CPM.

Predicting the likelihood of additional lymph node metastasis in sentinel lymph node positive breast cancer: validation of the Memorial Sloan-Kettering Cancer Centre (MSKCC) nomogram

AIM

To identify important clinicopathological parameters that are most helpful in predicting additional non-sentinel lymph node (SLN) metastasis among patients with a positive SLN biopsy in the Singapore breast cancer population.

METHODS

A total of 1409 patients who underwent SLN biopsy were reviewed over a 5 year period from July 2004 to October 2009. A Singapore General Hospital (SGH) nomogram was developed from predictors in the Memorial Sloan-Kettering Cancer Centre (MSKCC) nomogram using 266 patients with primary invasive breast cancer and a positive SLN biopsy who subsequently had an axillary lymph node dissection. The SGH nomogram was calibrated using bootstrapped data, while the MSKCC nomogram was calibrated using SGH data. The performance of these two nomograms was compared with the calculation of the area under the receiver-operator characteristics curve and adequacy indices.

RESULTS

The MSKCC nomogram achieved an area under the curve (AUC) of 0.716 (range 0.653-0.779) in our study population, while the SGH nomogram, which used only three pathological parameters, lymphovascular invasion, number of positive and negative SLN biopsies, achieved an AUC of 0.750 (range 0.691-0.808). The SGH nomogram with a higher adequacy index (0.969) provided better estimates compared with the MSKCC nomogram (0.689).

CONCLUSIONS

The use of the MSKCC nomogram was validated in our local patient population. The SGH nomogram showed promise to be equally, if not, more predictive as a model in our own population, while using only three pathological parameters.

Do Asian breast cancer patients have poorer survival than their western counterparts? A comparison between Singapore and Stockholm

Introduction

The difference in breast cancer incidence and prognosis between ethnic groups seeks an explanation. We have recently shown that Swedish women are two to three times more likely to be diagnosed with breast cancer compared with Singaporean women. In the present paper, we compare breast cancer survival in the two countries.

Methods

We compared the survival of 10,287 Singaporean women and 17,090 Swedish women with breast cancer. Relative survival ratios were used to describe the prognosis in the two populations. A Poisson regression model was used to calculate relative risks for different follow-up periods, age groups, time of diagnosis and disease stages.

Results

The majority of the Swedish women had local cancer (80%) compared with Singaporean women (51%). The overall 5-year relative survival of the Swedish women appeared better (80%) than that of the Singaporean women (70%). A similar survival pattern was observed, however, between the two countries in a stage-by-stage comparison. Survival improved for all women in Singapore over the two decades, but only in the premenopausal women in Stockholm. In 1980 to 1989, premenopausal Singaporean women had 27% increased risk of death compared with Swedish women, adjusted for stage and year of follow-up, while the postmenopausal women had 48% increased risk. In 1990 to 1999, this risk decreased by 19% and 22% for the premenopausal and postmenopausal Singaporean women compared with the Swedish women.

Conclusions

The stage-dependent prognosis was similar for Singaporean women and for Swedish women. Singaporean women, both premenopausal and postmenopausal, had pronounced improvement in prognosis over the calendar periods, probably contributed by marked economic improvement, leading to better medical facilities and management with increased awareness of patients to diagnosis and treatment, as well as improved treatment options. Improvement seen only in the premenopausal women in Stockholm was probably due to improved treatment options.

Management of inpatients exposed to an outbreak of severe acute respiratory syndrome (SARS)

This is a prospective observational study of a cohort of inpatients exposed to a severe acute respiratory syndrome (SARS) outbreak. Strict infection control policies were instituted. The 70 patients exposed to the SARS outbreak were isolated from the rest of the hospital. They were triaged, quarantined and cohorted in three open plan wards. Selective isolation was carried out immediately when symptoms and signs suspicious of SARS manifested clinically. The patients' ages ranged from 21 to 90 years and 56% had surgery before the quarantine. Sixteen patients with unexplained fever during the period of quarantine were isolated, seven of whom were eventually diagnosed with probable SARS. The crude incidence of SARS in our cohort was 10%. The SARS case fatality was 14%. No secondary transmission of the SARS virus within the cohort was observed. Strict infection control, together with appropriate triaging, cohorting and selective isolation, is an effective and practical model of intervention in cohorts exposed to a SARS outbreak. Such a management strategy eases the logistic constraints imposed by demands for large numbers of isolation facilities in the face of a massive outbreak.

Carcinoma of the rectum with a single penile metastasis

Metastatic disease of colon and rectal carcinoma accounts for a high proportion of cancer related deaths. The common organs involved in metastatic diseases include liver, lung, brain and bone. Although, theoretically possible, metastasis to the other organs are rare. We report the first case of carcinoma of the rectum with a solitary metastasis to the glans penis.