Immune checkpoint inhibitor therapy in locally advanced MSI GI malignancies.

Locally advanced gastrointestinal (GI) malignancies have conventionally been treated in a multimodal fashion that combines (neo)adjuvant chemotherapy with or without radiation and definitive surgical resection. Clinical data have demonstrated the reduced responsiveness of GI malignancies with microsatellite instability (MSI) to both adjuvant and neoadjuvant systemic chemotherapy when compared with microsatellite stable (MSS) disease. The elevated tumor mutational burden associated with MSI tumors of all types sensitizes these tumors to the effects of immune checkpoint blockade in the metastatic setting, which led to tumor-agnostic approval of immune checkpoint inhibitors in this context. The recent demonstration of greater sensitivity and high pathologic complete response rates to neoadjuvant immunotherapy in locally advanced GI malignancies may ultimately establish a novel treatment paradigm and herald potential nonoperative management of this distinct subgroup of GI malignancies. This article provides an overview of immune checkpoint inhibitor therapy in locally advanced MSI GI malignancies. It also covers the clinical significance of MSI status across the GI cancer spectrum, the available data demonstrating differential responses of MSI and MSS disease to conventional chemotherapy, and the biological rationale for novel strategies utilizing immunotherapy in the neoadjuvant, adjuvant, and nonoperative settings.

Use of real-time respiratory function monitor improves neonatal face mask ventilation: Cross-over simulation study.

BACKGROUND: Neonatal resuscitation airway training can be difficult as there is no feedback on the face mask technique. "JUNO" is a training respiratory function monitor that provides feedback on mask leak, ventilatory rate, and tidal volume. OBJECTIVE: To evaluate whether the use of the JUNO improves face mask ventilation techniques in manikin models. METHODS: We conducted an observational cross-over study with our unit staff. Following instructions, each participant performed a single-person technique, followed by a two-person technique with no JUNO feedback. This was repeated with JUNO feedback visible. A similar sequence was performed both in term and preterm manikins, giving a total of 8 sequences. Each participant was instructed to perform 1 min of positive pressure ventilation providing 30 inflations/minute for all of the simulations. Each of the simulation data underwent a data cleaning process. RESULTS: Thirty-eight subjects provided a total of 304 sequences of positive pressure ventilation. A total of 13 354 inflations were analyzed. The feedback group had significantly lower rates of inflations with leak >60%, lower rates of excessive tidal volumes, lower mean leak percentage, and a lower mean inspiratory tidal volumes. When analyzed based on the technique (single person and two-person), similar positive results were noted in the "feedback group", across all the strata of staff. All of the staff reported that JUNO improved their ventilation technique and would recommend it for staff training. CONCLUSIONS: The use of JUNO significantly improved mask ventilation consistently across manikin types, staff roles, and techniques (either single- or two-person).

Prevalence of Insomnia in an Oncology Patient Population: An Irish Tertiary Referral Center Experience.

BACKGROUND: The NCCN Guidelines for Survivorship recommend dedicated sleep assessment. Reported insomnia prevalence in the general Irish population is 6% to 15%. Reported insomnia prevalence internationally among new/recently diagnosed patients with cancer varies from 30.9% to 54.3%. Insomnia prevalence has not been previously quantified in an Irish oncology cohort. METHODS: A 40-item questionnaire was prospectively administered to ambulatory patients with cancer aged ≥18 years. Prespecified criteria to define insomnia syndrome combined those of the International Classification of Sleep Disorders, version 1, and the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). The Hospital Anxiety and Depression Scale-Depression/Anxiety (HADS-D/A) was used to screen for potential confounding variables. RESULTS: The response rate to the questionnaire was 87% (294/337). The predominant respondent age group was 55 to 64 years (26%; 77/294), 70.7% were female (208/294), and the most common cancer subtypes were breast (37.4%), colorectal (12.9%), and lung (12.2%). A total of 62% (183/294) of patients reported sleep disturbance after diagnosis, 63% (115/183) reported moderate/severe distress related to this disturbance, and 37% (61/183) reported a significant impact on physical function. Although 33% (98/294) met insomnia syndrome criteria, only 34% (33/98) of these patients had a preexisting history of sleep disturbance. Female sex, age <65 years, cancer subtype, alcohol consumption, and HADS-D/A ≥11 were associated with statistically significant higher odds ratios (OR) of insomnia syndrome. Multivariate analysis identified breast cancer (OR, 3.17; P=.01), age <65 years (OR, 1.8; P=.03), and alcohol consumption (OR, 2.3; P=.005) as independent predictors of insomnia syndrome. CONCLUSIONS: Insomnia syndrome prevalence in this cohort is comparable to that reported previously and supports dedicated sleep assessment. This study identifies potentially modifiable risk factors for insomnia and demonstrates additional utility of the HADS score in identifying patients at risk.

Upper Gastrointestinal Cancers and the Role of Genetic Testing.

Beyond the few established hereditary cancer syndromes with an upper gastrointestinal cancer component, there is increasing recognition of the contribution of novel pathogenic germline variants (gPVs) to upper gastrointestinal carcinogenesis. The detection of gPVs has potential implications for novel treatment approaches of the index cancer patient as well as long-term implications for surveillance and risk-reducing measures for cancer survivors and far-reaching implications for the patients' family. With widespread availability of multigene panel testing, new associations may be identified with germline-somatic integration being critical to determining true causality of novel gPVs. Comprehensive cancer care should incorporate both somatic and germline testing.

Molecular and Clinical Determinants of Acquired Resistance and Treatment Duration for Targeted Therapies in Colorectal Cancer.

PURPOSE: Targeted therapies have improved outcomes for patients with metastatic colorectal cancer, but their impact is limited by rapid emergence of resistance. We hypothesized that an understanding of the underlying genetic mechanisms and intrinsic tumor features that mediate resistance to therapy will guide new therapeutic strategies and ultimately allow the prevention of resistance. EXPERIMENTAL DESIGN: We assembled a series of 52 patients with paired pretreatment and progression samples who received therapy targeting EGFR (n = 17), BRAF V600E (n = 17), KRAS G12C (n = 15), or amplified HER2 (n = 3) to identify molecular and clinical factors associated with time on treatment (TOT). RESULTS: All patients stopped treatment for progression and TOT did not vary by oncogenic driver (P = 0.5). Baseline disease burden (≥3 vs. <3 sites, P = 0.02), the presence of hepatic metastases (P = 0.02), and gene amplification on baseline tissue (P = 0.03) were each associated with shorter TOT. We found evidence of chromosomal instability (CIN) at progression in patients with baseline MAPK pathway amplifications and those with acquired gene amplifications. At resistance, copy-number changes (P = 0.008) and high number (≥5) of acquired alterations (P = 0.04) were associated with shorter TOT. Patients with hepatic metastases demonstrated both higher number of emergent alterations at resistance and enrichment of mutations involving receptor tyrosine kinases. CONCLUSIONS: Our genomic analysis suggests that high baseline CIN or effective induction of enhanced mutagenesis on targeted therapy underlies rapid progression. Longer response appears to result from a progressive acquisition of genomic or chromosomal instability in the underlying cancer or from the chance event of a new resistance alteration.

Lynch Syndrome and Somatic Mismatch Repair Variants in Pancreas Cancer.

Importance: Microsatellite (MS) instability (MSI-H) occurs frequently in Lynch syndrome (LS)-associated tumors and is associated with response to immune checkpoint blockade (ICB) therapy. MSI-H is conferred by germline or somatic variants in mismatch repair genes. The contribution of somatic oncogenesis to MSI-H in pancreatic cancer (PC) is unknown. Objective: To evaluate an LS-related PC cohort to define clinicogenomic features, describe somatic MSI-H cases (germline negative), characterize response to ICB, and guide preferred MS testing methods. Design, Setting, and Participants: This single-institution, retrospective analysis was conducted from March 2012 to July 2023 at Memorial Sloan Kettering Cancer Center and included 55 patients with PC and either an LS germline pathogenic variant (gPV) or somatic mismatch repair (MMR) variant. Main Outcomes and Measures: Composite MMR and MS status determined using orthogonal methods. An artificial intelligence classifier was used to account for low-cellularity specimens. Demographic and clinical data were abstracted from medical record. Zygosity status and somatic comutation landscape analyzed. Results: Fifty-five patients (23 women [42%]) had PC and an MMR variant: 32 (58%) had LS (LS cohort) and 23 (42%) had a somatic MMR variant (no germline pathogenic variant, somatic MMR cohort). In the LS cohort, 10 (31%) had gMSH2, 9 (28%) gMSH6, 8 (25%) gPMS2, 4 (13%) gMLH1, 1 (3%) gEPCAM. The median age at diagnosis was 68 years (range, 45-88 years). For composite MS status, 17 (59%) were MSI-H, 12 (41%) MS stable, and 3 MS unknown. Five cases were reclassified as MSI-H by the artificial intelligence classifier. In the somatic MMR cohort, 11 (48%) had MSH6, 7 (30%) MLH1, 3 (13%) MSH2, and 2 (9%) PMS2. The median age at diagnosis was 72 years (range, 66-85 years). For composite MS status, 10 (43%) were MSI-H, 11 (48%) MS stable, and 2 (9%) MS indeterminate. Six cases were reclassified as MSI-H by the artificial intelligence classifier. For the LS and somatic MMR cohorts, 20 received ICB (n = 17 MSI-H). The median ICB duration was 27.7 months (95% CI, 11.5 to not reached); the disease control rate was 80%. Conclusion: The results of this cross-sectional study suggest that MSI-H occurs due to LS or somatic oncogenesis in PC. Orthogonal MS testing is key in PC; the artificial intelligence classifier reclassified approximately 20% of cases, most of which were low cellularity. ICB for patients with LS or somatic MSI-H PC provided significant benefit.

Precision medicine for pancreatic cancer: characterizing the clinicogenomic landscape and outcomes of KRAS G12C-mutated disease.

BACKGROUND: Mutated Kirsten rat sarcoma viral oncogene homolog (KRAS) is the most common oncogene alteration in pancreatic ductal adenocarcinoma, and KRAS glycine to cystine substitution at codon 12 (G12C) mutations (KRAS G12Cmut) are observed in 1%-2%. Several inhibitors of KRAS G12C have recently demonstrated promise in solid tumors, including pancreatic cancer. Little is known regarding clinical, genomics, and outcome data of this population. METHODS: Patients with pancreatic cancer and KRAS G12Cmut were identified at Memorial Sloan Kettering Cancer Center and via the American Association of Cancer Research Project Genomics, Evidence, Neoplasia, Information, Exchange database. Clinical, treatment, genomic, and outcomes data were analyzed. A cohort of patients at Memorial Sloan Kettering Cancer Center with non-G12C KRAS pancreatic cancer was included for comparison. RESULTS: Among 3571 patients with pancreatic ductal adenocarcinoma, 39 (1.1%) with KRAS G12Cmut were identified. Median age was 67 years, and 56% were female. Median body mass index was 29.2 kg/m2, and 67% had a smoking history. Median overall survival was 13 months (95% CI: 9.4 months, not reached) for stage IV and 26 months (95% CI: 23 months, not reached) for stage I-III. Complete genomic data (via American Association of Cancer Research Project Genomics, Evidence, Neoplasia, Information, Exchange database) was available for 74 patients. Most common co-alterations included TP53 (73%), CDKN2A (33%), SMAD4 (28%), and ARID1A (21%). Compared with a large cohort (n = 2931) of non-G12C KRAS-mutated pancreatic ductal adenocarcinoma, ARID1A co-mutations were more frequent in KRAS G12Cmut (P < .05). Overall survival did not differ between KRAS G12Cmut and non-G12C KRAS pancreatic ductal adenocarcinoma. Germline pathogenic variants were identified in 17% of patients; 2 patients received KRAS G12C-directed therapy. CONCLUSION: Pancreatic cancer and KRAS G12Cmut may be associated with a distinct clinical phenotype. Genomic features are similar to non-G12C KRAS-mutated pancreatic cancer, although enrichment of ARID1A co-mutations was observed. Targeting of KRAS G12C in pancreatic cancer provides a precedent for broader KRAS targeting in pancreatic cancer.

Adjuvant Modified FOLFIRINOX for Resected Pancreatic Adenocarcinoma (PDAC): Clinical Insights and Genomic Features from a Large Contemporary Cohort.

BACKGROUND: Adjuvant mFOLFIRINOX (mFFX) is standard of care for fit individuals with resected pancreatic ductal adenocarcinoma (PDAC). There are limited data on adjuvant mFFX outcomes outside clinical trials. METHODS: Institutional databases queried to identify patients with resected PDAC who received ≥1 dose adjuvant mFFX. Primary endpoints: recurrence free survival (RFS), overall survival (OS). Secondary endpoints: clinical factors, genomic features associated with outcomes. RFS and OS were estimated with Kaplan-Meier. Cox proportional hazards regression model was used to associate clinico-genomic features correlated with survival outcomes. RESULTS: N = 147 identified between 01/2015-01/2023. Median age: 67 years; N = 57 (39%) >70 years. Unfavorable prognostic features: N = 52 (36%) N2 nodal status, N = 115 (78%) lymphovascular invasion), and N = 133 (90%) perineural invasion. Median time from surgery to start mFFX: 1.78 months (m) (IQR 1.45, 2.12). N = 124 (84%) completed 12 doses; N = 98 (67%) stopped oxaliplatin early for neuropathy (median 10 doses; range 4-12). Further dosing characteristics are summarized in Supplementary Table 3. With median follow up of 35.1 m, median RFS (mRFS) 26 m (95% CI 19, 39) and median OS (mOS) not reached. For >70 cohort, mRFS 23 m (95% CI 14, NR) and mOS 51 m (95% CI 37, NR). mFFX started <8 weeks from resection associated with improved RFS (HR 0.62; 95% CI 0.41, 0.96; p = .033) and OS (HR 0.53; 95% CI 0.3, 0.94; p = .030). KRAS mutation and whole genome doubling trended to shorter RFS and OS. Homologous recombination deficiency status did not confer improved survival outcomes. CONCLUSIONS: Adjuvant mFFX is effective and tolerable in resected PDAC in a non-trial setting, including for patients >70 years.

Early-Onset GI Cancers: Rising Trends, Genetic Risks, Novel Strategies, and Special Considerations.

Cancers in young adults (commonly described as early-onset [EO] cancer) represent a group of malignancies that have unique and challenging biology and genetic, treatment, social, and psychological implications. Even more concerning is a rising trend of EO cancers in multiple tumor types. Research and investigation in EO cancers will help elucidate mechanisms of carcinogenesis, differences in biology and response to treatment, and the need for multidisciplinary care to ensure comprehensive treatment and support for young patients.

Neoplasia risk in patients with Lynch syndrome treated with immune checkpoint blockade.

Metastatic and localized mismatch repair-deficient (dMMR) tumors are exquisitely sensitive to immune checkpoint blockade (ICB). The ability of ICB to prevent dMMR malignant or pre-malignant neoplasia development in patients with Lynch syndrome (LS) is unknown. Of 172 cancer-affected patients with LS who had received ≥1 ICB cycles, 21 (12%) developed subsequent malignancies after ICB exposure, 91% (29/32) of which were dMMR, with median time to development of 21 months (interquartile range, 6-38). Twenty-four of 61 (39%) ICB-treated patients who subsequently underwent surveillance colonoscopy had premalignant polyps. Within matched pre-ICB and post-ICB follow-up periods, the overall rate of tumor development was unchanged; however, on subgroup analysis, a decreased incidence of post-ICB visceral tumors was observed. These data suggest that ICB treatment of LS-associated tumors does not eliminate risk of new neoplasia development, and LS-specific surveillance strategies should continue. These data have implications for immunopreventative strategies and provide insight into the immunobiology of dMMR tumors.

Targeting MET amplification in Gastro-oesophageal (GO) malignancies and overcoming MET inhibitor resistance: challenges and opportunities.

INTRODUCTION: MET, the hepatocyte growth factor receptor is amplified in 8% of gastroesophageal (GO) malignancies and associated with poor prognosis. Therapeutic targeting of MET amplification and MET mutations has the potential to improve outcomes for patients with GO cancers (GOC). AREAS COVERED: The efficacy of MET inhibition (METi) in preclinical studies has yet to translate into meaningful improvements in the treatment paradigm for unselected GOC. MET amplification has been proposed as a superior modality for patient selection; however even if confirmed, frequency and duration of response to METi are limited by rapid activation of primary and secondary resistance pathways. These observations illustrate the challenges inherent in the application of precision oncology predicated on the theory of oncogenic addiction. EXPERT OPINION: A standardized definition of MET positivity is critical to enhance patient selection. Early successes targeting the METex14 skipping mutation demonstrate the potent therapeutic effects of METi in a clearly molecularly defined cohort. There is robust preclinical rationale and early-phase data supporting exploitation of immune system interaction with MET. Pragmatic investigation of rational therapeutic combinations based on molecular profiling of both primary and metastatic disease sites with sequential circulating tumor DNA analysis can inform successful clinical development of METi agents in GOC.

DNA Damage Repair Deficiency in Pancreatic Ductal Adenocarcinoma: Preclinical Models and Clinical Perspectives.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers worldwide, and survival rates have barely improved in decades. In the era of precision medicine, treatment strategies tailored to disease mutations have revolutionized cancer therapy. Next generation sequencing has found that up to a third of all PDAC tumors contain deleterious mutations in DNA damage repair (DDR) genes, highlighting the importance of these genes in PDAC. The mechanisms by which DDR gene mutations promote tumorigenesis, therapeutic response, and subsequent resistance are still not fully understood. Therefore, an opportunity exists to elucidate these processes and to uncover relevant therapeutic drug combinations and strategies to target DDR deficiency in PDAC. However, a constraint to preclinical research is due to limitations in appropriate laboratory experimental models. Models that effectively recapitulate their original cancer tend to provide high levels of predictivity and effective translation of preclinical findings to the clinic. In this review, we outline the occurrence and role of DDR deficiency in PDAC and provide an overview of clinical trials that target these pathways and the preclinical models such as 2D cell lines, 3D organoids and mouse models [genetically engineered mouse model (GEMM), and patient-derived xenograft (PDX)] used in PDAC DDR deficiency research.

Genomic profiling of a dedifferentiated mucosal melanoma following exposure to immunotherapy.

The treatment landscape for metastatic melanoma has been revolutionised by the introduction of immunotherapy and targeted therapies. Despite these advances, some patients exhibit primary or acquired resistance to treatment. We present the case of a resected mucosal melanoma that on relapse underwent transformation to a dedifferentiated state. The relapsed tumour was phenotypically disparate and demonstrated loss of all typical melanoma-associated immunohistochemical markers. Furthermore, it demonstrated aggressive biological behaviour and immunotherapy resistance. We performed genomic profiling of the original and relapsed tumour to further elucidate the mechanisms underlying this rare phenomenon. Mass spectrometry-based single-nucleotide polymorphism genotyping technology was used to screen for mutations in the original and recurrent tumour. Whole-exome sequencing was performed on the original tumour, recurrent tumour and blood. Both the original and recurrent tumour shared a NRAS mutation, a similar aneuploidy profile and proportion of somatic single-nucleotide variants. However, in contrast to the original tumour, the recurrent tumour demonstrated a lower mutational burden and deletions in the CDKN2A/CDKN2B and CHEK2 genes. The genomic similarity between the original and recurrent tumour attests to a common ancestry and the possible existence of nongenomic drivers inciting phenotype plasticity. In contrast, the low mutational load and potential inactivation of tumour suppressor genes in the recurrent tumour may underlie its rapid proliferative rate and immunoresistance. Dynamic treatment models are desired in the future to track the genomic and epigenetic evolution of a tumour to guide optimal therapy choice and sequencing.

Similar overall survival with reduced vs. standard dose bevacizumab monotherapy in progressive glioblastoma.

INTRODUCTION: Bevacizumab has demonstrated activity in glioblastoma (GBM), but the true benefits and optimal dose-schedule are debated. A lower dose-schedule than standard-dose bevacizumab (10 mg/kg 2-weekly) might offer similar benefits with lower costs. At our Institution, patients are randomly assigned at time of primary diagnosis to Neuro-Oncologists, who have varying practices in terms of bevacizumab dose-schedule upon progression. METHODS: In a retrospective analysis we examined overall survival (OS), measured from first administered bevacizumab dose until death, according to dose-schedule. Patients with de novo WHO Grade IV GBM who received standard- or reduced-dose (5 mg/kg 2-weekly) bevacizumab were included. MGMT methylation status and time from diagnosis to bevacizumab start were examined as prognostic variables. Clinical benefit and a comparative cost analysis were assessed. RESULTS: In total, 1127 bevacizumab doses were administered to 118 patients [Median: 7, Range: 1-44]. Median OS (mOS) was 5.8 months. 69 (59%) patients received standard-dose bevacizumab (mOS: 5.97 months) and 49 patients received reduced-dose (mOS: 5.7 months). No statistically significant difference in OS between dosing schedule was seen (HR: 1.11, P-value: .584). Patients with MGMT methylated tumors (43%) had improved OS compared to those with unmethylated tumors; 7.03 vs 4.97 months (HR: 0.61, P-value: .027). If all patients were treated with reduced-dose bevacizumab, an estimated €2.4M cost reduction would be observed. CONCLUSIONS: In this retrospective study, reduced-dose bevacizumab schedule resulted in similar OS to standard-dose bevacizumab monotherapy with substantial cost savings. MGMT methylation appears to convey a survival benefit in the setting of bevacizumab treatment for progressive GBM.

Recurrent vulvar melanoma in a patient with neurofibromatosis and gastrointestinal stromal tumour.

We report a case of a 51-year-old woman with neurofibromatosis who presented in 2012 with postmenopausal bleeding. Excision biopsy of a pigmented lesion of the labia minora was consistent with an ulcerated vulvar BRAF wild type malignant melanoma (MM). Initial excision was followed by radical vulvectomy and adjuvant interferon. Local recurrence in January 2017 was further resected. Positron emission tomography (PET)-CT in May 2017 identified an FDG avid omental deposit; consistent histologically with MM when resected. Postoperative PET-CT in August 2017 demonstrated local recurrence. In the setting of resected stage IV disease and a third local recurrence, the decision was made to instigate immunotherapy. Vulvar melanoma is rare accounting for 0.2% of all melanoma. Presentation is typically a decade later than cutaneous melanoma with a tendency to late metastases and poorer prognosis. Given their rarity the treatment paradigm is less clearly defined and largely extrapolated from that of cutaneous melanomas.

ßhCG-secreting osteosarcoma.

A 35-year-old woman presented to our institution with tender, right knee swelling. Radiological and pathological work-up revealed metastatic osteosarcoma. Prior to the initiation of chemotherapy, she underwent a routine urine pregnancy test and was surprised with a positive result. Serum beta human chorionic gonadotropin (ßhCG) levels were also consistently positive and rising. No gestational sac was seen at transvaginal ultrasound. The paraneoplastic ectopic secretion of ßhCG has been well described in gestational trophoblastic and gonadal tumours but has very rarely been associated with other tumour types. This patient's ßhCG level was reflective of osteosarcoma activity and normalised with response to chemotherapy. The prognostic implications of ßhCG expression in more diverse tumours is unclear; however, where raised, it can be used to monitor disease activity.

Monitoring Ionizing Radiation Exposure for Cardiotoxic Effects of Breast Cancer Treatment.

Serial assessments of left ventricular ejection fraction (LVEF) are customary in patients with breast cancer receiving trastuzumab. Radionuclide angiography (RNA) is often used; however, a typical monitoring schedule could include 5 scans in a year. We evaluated the proportion of imaging-related ionizing radiation attributable to RNA in 115 patients with breast cancer, from 3 medical centers in the United States, Ireland, and Japan, who completed 12 months of trastuzumab treatment. Estimated radiation dose (ERD) was used to calculate exposure associated with imaging procedures spanning the 18 months before and after trastuzumab therapy. In addition, 20 cardiologists and oncologists from participating centers were surveyed for their opinions regarding the contribution of RNA to overall radiation exposure during trastuzumab treatment. When RNA was used to monitor LVEF, the mean ERD from imaging was substantial (34 ± 24.3 mSv), with the majority attributable solely to RNA (24.7 ± 14.8 mSv, 72.6%). Actual ERD associated with RNA in this population differed significantly from the perception in surveyed cardiologists and oncologists; 70% of respondents believed that RNA typically accounted for 0% to 20% of overall radiation exposure from imaging; RNA actually accounted for more than 70% of ERD. In conclusion, RNA was used to monitor LVEF in most patients in this cohort during and after trastuzumab therapy. This significantly increased ERD and accounted for a greater proportion of radiation than that perceived by surveyed physicians. ERD should be taken into account when choosing a method of LVEF surveillance. Alternative techniques that do not use radiation should be strongly considered.

Are there sex differences in Fetal Abdominal Subcutaneous Tissue (FAST) measurements?

OBJECTIVE: To determine if Fetal Abdominal Subcutaneous Tissue (FAST) measurements using antenatal ultrasound differ between male and female fetuses. STUDY DESIGN: Women who had an ultrasound examination for fetal growth between 20 and 40 weeks gestation were studied. Women with diabetes mellitus were excluded. The fetal anterior abdominal subcutaneous tissue was measured on the anterior abdominal wall in millimetres anterior to the margins of the ribs, using magnification at the level of the abdominal circumference. The fetal sex was recorded after delivery. RESULTS: A total of 557 fetuses were measured, 290 male and 267 female. The FAST measurements increased with gestational age. The FAST increased at the same rate for both male and female fetuses and at any given week there was no sex difference. CONCLUSIONS: The increased fat composition in females reported after birth was not found in abdominal wall subcutaneous fat measurements using ultrasound during pregnancy. Antenatal centile charts for FAST do not need to be based on sex.