Acetylsalicylic acid suppression of the PI3K pathway as a novel medical therapy for head and neck lymphatic malformations

Management and Outcomes of Pediatric Lymphatic Malformations: A Systematic Review From the APSA Outcomes and Evidence-Based Practice Committee

BACKGROUND

Significant variation in management strategies for lymphatic malformations (LMs) in children persists. The goal of this systematic review is to summarize outcomes for medical therapy, sclerotherapy, and surgery, and to provide evidence-based recommendations regarding the treatment.

METHODS

Three questions regarding LM management were generated according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Publicly available databases were queried to identify articles published from January 1, 1990, to December 31, 2021. A consensus statement of recommendations was generated in response to each question.

RESULTS

The initial search identified 9326 abstracts, each reviewed by two authors. A total of 600 abstracts met selection criteria for full manuscript review with 202 subsequently utilized for extraction of data. Medical therapy, such as sirolimus, can be used as an adjunct with percutaneous treatments or surgery, or for extensive LM. Sclerotherapy can achieve partial or complete response in over 90% of patients and is most effective for macrocystic lesions. Depending on the size, extent, and location of the malformation, surgery can be considered.

CONCLUSION

Evidence supporting best practices for the safety and effectiveness of management for LMs is currently of moderate quality. Many patients benefit from multi-modal treatment determined by the extent and type of LM. A multidisciplinary approach is recommended to determine the optimal individualized treatment for each patient.

LEVEL OF EVIDENCE: 4

Delaying Invasive Treatment in Unilateral Head and Neck Lymphatic Malformation Improves Outcomes

OBJECTIVES

Large (De Serres stage [IV-V]) head and neck lymphatic malformations (HNLMs) often have multiple, high-risk, invasive treatments (ITs) to address functional compromise. Logically reducing HNLM ITs should reduce treatment risk. We tested whether delaying HNLM ITs reduces total IT number.

MATERIALS

Consecutive HNLM patients (n = 199) between 2010 and 2017, aged 0-18 years.

METHODS

ITs (surgery or sclerotherapy) were offered for persistent or dysfunction causing HNLMs. Treatment effectiveness categorized by IT number: optimal (0-1), acceptable (2-5), or suboptimal (>5). Clinical data were summarized, and outcome associations tested (χ² ). Relative risk (RR) with a Poisson working model tested whether HNLM observation or IT delay (>6 months post-diagnosis) predicts treatment success (i.e., ≤1 IT).

RESULTS

Median age at HNLM diagnosis was 1.3 months (interquartile range [IQR] 0-45 m) with 107/199(54%) male. HNLM were stage I-III (174 [88%]), IV-V (25 [13%]). Initial treatment was observation (70 [35%]), invasive (129 [65%]). Treatment outcomes were optimal (137 [69%]), acceptable (36 [18%]), and suboptimal (26 [13%]). Suboptimal outcome associations: EXIT procedure, stage IV-V, oral location, and tracheotomy (p < 0.001). Stage I-III HNLMs were initially observed compared with stage I-III having ITs within 6 months of HNLM diagnosis, had a 82% lower relative treatment failure risk ([i.e., >1 IT], RR = 0.09, 95% CI 0.02-0.36, p < 0.001). Stage I-III HNLMs with non-delayed ITs had reduced treatment failure risk compared with IV-V (RR = 0.47, 95% CI 0.33-0.66, p < 0.001).

CONCLUSION

Observation and delayed IT in stage I-III HNLM ("Grade 1") is safe and reduces IT (i.e., ≤1 IT). Stage IV-V HNLMs ("Grade 2") with early IT have a greater risk of multiple ITs.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:956-962, 2023.

Primary targeted medical therapy for management of bilateral head and neck lymphatic malformations in infants

OBJECTIVES

Patients born with bilateral head and neck lymphatic malformations (BHNLMs) often require multiple invasive treatments, including tracheostomy. We hypothesized that primary targeted medical therapy (pTMT) with diagnostic needle aspiration reduces the need for invasive therapy such as surgical resection and/or sclerotherapy.

METHODS

Retrospective case review was performed of infants with BHNLMs (Grade 2 or De Serres stage IV and V) treated only at our institution from 2000 to 2021. Patients were divided into two cohorts: those managed with pTMT and those managed with observation, sclerotherapy, or surgical intervention (non-pTMT). Data regarding interventions, clinical outcomes, morbidity, and mortality were analyzed with descriptive statistics.

RESULTS

Nine children with BHNLMs met inclusion criteria. Three (33%) were in the pTMT cohort and six (66%) were non-pTMT. Eight (89%) malformations were genotyped, and all demonstrated hotspot PIK3CA variants. All pTMT patients had sirolimus initiated in the first month of life and underwent needle aspiration of malformation cyst fluid for cell-free DNA samples. All pTMT patients tolerated medical therapy. For the non-pTMT cohort, primary treatment included none (deceased, n = 1, 17%), observation with needle aspiration (n = 1, 17%), surgical resection (n = 2, 33%), or combination surgery and sclerotherapy (n = 2, 33%). Intubation duration, intensive care and initial hospital length of stay were not different between cohorts. Four non-pTMT patients (67%) required tracheostomy, and two (33%) died prior to discharge. All pTMT patients survived and none required tracheostomy. Non-pTMT patients required a median of two invasive therapies prior to discharge (IQR 1-4) and a mean total of 13 over the course of their lifetime (IQR 1-16), compared to the pTMT group who did not require any lifetime invasive therapy, even after initial pTMT and discharge home.

CONCLUSION

This study compares patients with BHNLMs (Grade 2) treated with pTMT versus those treated with observation or invasive therapy. Patients treated with pTMT required no surgical or invasive procedural treatment of their malformations, no tracheostomy placement, no unplanned readmissions after discharge, and had no mortalities. Needle aspiration was useful as a therapeutic adjunct for cell-free DNA diagnosis of PIK3CA variants, which guided TMT.

Alpelisib for the treatment of PIK3CA-related head and neck lymphatic malformations and overgrowth

PURPOSE

PIK3CA-related overgrowth spectrum (PROS) conditions of the head and neck are treatment challenges. Traditionally, these conditions require multiple invasive interventions, with incomplete malformation removal, disfigurement, and possible dysfunction. Use of the PI3K inhibitor alpelisib, previously shown to be effective in PROS, has not been reported in PIK3CA-associated head and neck lymphatic malformations (HNLMs) or facial infiltrating lipomatosis (FIL). We describe prospective treatment of 5 children with PIK3CA-associated HNLMs or head and neck FIL with alpelisib monotherapy.

METHODS

A total of 5 children with PIK3CA-associated HNLMs (n = 4) or FIL (n = 1) received alpelisib monotherapy (aged 2-12 years). Treatment response was determined by parental report, clinical evaluation, diary/questionnaire, and standardized clinical photography, measuring facial volume through 3-dimensional photos and magnetic resonance imaging.

RESULTS

All participants had reduction in the size of lesion, and all had improvement or resolution of malformation inflammation/pain/bleeding. Common invasive therapy was avoided (ie, tracheotomy). After 6 or more months of alpelisib therapy, facial volume was reduced (range 1%-20%) and magnetic resonance imaging anomaly volume (range 0%-23%) were reduced, and there was improvement in swallowing, upper airway patency, and speech clarity.

CONCLUSION

Individuals with head and neck PROS treated with alpelisib had decreased malformation size and locoregional overgrowth, improved function and symptoms, and fewer invasive procedures.

Somatic activating BRAF variants cause isolated lymphatic malformations

Somatic activating variants in PIK3CA, the gene that encodes the p110α catalytic subunit of phosphatidylinositol 3-kinase (PI3K), have been previously detected in ∼80% of lymphatic malformations (LMs).^1,2 We report the presence of somatic activating variants in BRAF in individuals with LMs that do not possess pathogenic PIK3CA variants. The BRAF substitution p.Val600Glu (c.1799T>A), one of the most common driver mutations in cancer, was detected in multiple individuals with LMs. Histology revealed abnormal lymphatic channels with immunopositivity for BRAF^V600E in endothelial cells that was otherwise indistinguishable from PIK3CA-positive LM. The finding that BRAF variants contribute to low-flow LMs increases the complexity of prior models associating low-flow vascular malformations (LM and venous malformations) with mutations in the PI3K-AKT-MTOR and high-flow vascular malformations (arteriovenous malformations) with mutations in the RAS-mitogen-activated protein kinase (MAPK) pathway.³ In addition, this work highlights the importance of genetic diagnosis prior to initiating medical therapy as more studies examine therapeutics for individuals with vascular malformations.