The use of hyaluronic acid hydrogel as a tumour bed marker in breast-conserving therapy

Stabilised Hyaluronic Acid (sHA) gel as a novel marker for breast cancer tumour bed cavity: Surgical feasibility

Introduction

Consistent delineation of the breast conserving surgery (BCS) tumour bed (TB) for breast cancer remains a challenge for radiation oncologists. Accurate delineation allows for better local control and reduces toxicity when planning partial breast or TB boost radiation therapy (RT).

Methods

In the operating theatre (OT) breast surgeons inserted stabilised hyaluronic acid (sHA) gel as small drops approximately one cm into the walls surrounding the resection cavity. Surgical feasibility was determined by the rate of successful sHA gel insertion procedure, the ease of insertion as rated by surgeons, the time required for insertion procedure, the quantity used, and any adverse events (AE) relating to sHA gel insertion.

Results

Thirty-five patients were enrolled. All patients underwent sHA gel insertion successfully. The procedure added a median of 2.8 min to the OT time and was rated as 'easy' in 89 % of patients. There were no immediate AE in OT. Five (14 %) patients experienced a grade 2 or higher AE. Three of the five patients were prescribed oral antibiotics for breast infection. Two of the five patients experienced a grade 3 AE - haematoma which required evacuation in OT day 1 post-BCS, and infected seroma which required drainage and washout in OT 2 months post-BCS. All five patients recovered and underwent the planned adjuvant therapies for their BC. The AE data reflects common risks with standard BCS and are not clearly attributed to sHA gel insertion alone.

Conclusion

We show that sHA gel is surgically feasible as a marker to help define the TB cavity for post-BCS adjuvant MRI-based RT planning.

Carboxymethylcellulose based self-healing hydrogel with coupled DOX as Camptothecin loading carrier for synergetic colon cancer treatment

The self-healing hydrogels have important applications in biomedication as drug release carrier. In this research, the Doxorubicin (DOX) was coupled onto oxidized carboxymethylcellulose (CMC) (CMC-Ald) to fabricate self-healing hydrogel with intrinsic antitumor property and loaded with Camptothecin (CPT) for synergetic antitumor treatment. The DOX coupled CMC-Ald (CMC-AD) was reacted with poly(aspartic hydrazide) (PAH) to fabricate injectable self-healing hydrogel. The coupled DOX avoided the burst release of the drug and the 100 % CPT loaded hydrogel could take the advantages of both drugs to enhance the synergetic antitumor therapeutic effect. The in vitro and in vivo results revealed the CPT loaded CMC-AD/PAH hydrogel showed enhanced antitumor property and reduced biotoxicity of the drugs. These properties demonstrate that the CMC-AD/PAH hydrogel has great application prospects in biomedication.

Assessing Interobserver Variability in the Delineation of Structures in Radiation Oncology: A Systematic Review

PURPOSE

The delineation of target volumes and organs at risk is the main source of uncertainty in radiation therapy. Numerous interobserver variability (IOV) studies have been conducted, often with unclear methodology and nonstandardized reporting. We aimed to identify the parameters chosen in conducting delineation IOV studies and assess their performances and limits.

METHODS AND MATERIALS

We conducted a systematic literature review to highlight major points of heterogeneity and missing data in IOV studies published between 2018 and 2021. For the main used metrics, we did in silico analyses to assess their limits in specific clinical situations.

RESULTS

All disease sites were represented in the 66 studies examined. Organs at risk were studied independently of tumor site in 29% of reviewed IOV studies. In 65% of studies, statistical analyses were performed. No gold standard (GS; ie, reference) was defined in 36% of studies. A single expert was considered as the GS in 21% of studies, without testing intraobserver variability. All studies reported both absolute and relative indices, including the Dice similarity coefficient (DSC) in 68% and the Hausdorff distance (HD) in 42%. Limitations were shown in silico for small structures when using the DSC and dependence on irregular shapes when using the HD. Variations in DSC values were large between studies, and their thresholds were inconsistent. Most studies (51%) included 1 to 10 cases. The median number of observers or experts was 7 (range, 2-35). The intraclass correlation coefficient was reported in only 9% of cases. Investigating the feasibility of studying IOV in delineation, a minimum of 8 observers with 3 cases, or 11 observers with 2 cases, was required to demonstrate moderate reproducibility.

CONCLUSIONS

Implementation of future IOV studies would benefit from a more standardized methodology: clear definitions of the gold standard and metrics and a justification of the tradeoffs made in the choice of the number of observers and number of delineated cases should be provided.

Application of Hydrogels as Carrier in Tumor Therapy: A Review

Cancer is one of the most intractable diseases in the world because of its high recurrence rate, high metastasis rate and high lethality rate. Traditional chemotherapy, radiotherapy and surgery have unsatisfactory therapeutic effects and cause many severe side effects at the same time. Hydrogel is a new type of biomaterial with the advantages of good biocompatibility and easy degradation, which can be used as a carrier of functional nanomaterials for tumor therapy. Herein, we represent the progress of hydrogels with different skeletons and their application as carrier in tumor treatment. The hydrogels are listed as polyethylene glycol-based hydrogels, chitosan-based hydrogels, peptide-based hydrogels, hyaluronic acid-based hydrogels, steroid-based hydrogels and other hydrogels by skeletons, and their properties, modifications and toxicities were introduced. Some representative applications of combined hydrogels with nanomaterial for chemotherapy, photodynamic therapy, photothermal therapy, sonodynamic therapy, chemodynamic therapy and synergistic therapy are highlighted.

Advances in Hyaluronic Acid for Biomedical Applications

Hyaluronic acid (HA) is a large non-sulfated glycosaminoglycan that is the main component of the extracellular matrix (ECM). Because of its strong and diversified functions applied in broad fields, HA has been widely studied and reported previously. The molecular properties of HA and its derivatives, including a wide range of molecular weights but distinct effects on cells, moisture retention and anti-aging, and CD44 targeting, promised its role as a popular participant in tissue engineering, wound healing, cancer treatment, ophthalmology, and cosmetics. In recent years, HA and its derivatives have played an increasingly important role in the aforementioned biomedical fields in the formulation of coatings, nanoparticles, and hydrogels. This article highlights recent efforts in converting HA to smart formulation, such as multifunctional coatings, targeted nanoparticles, or injectable hydrogels, which are used in advanced biomedical application.

Polysaccharide-based biopolymer hydrogels for heavy metal detection and adsorption

BACKGROUND

With rapid development in agriculture and industry, water polluted with heavy metallic ions has come to be a serious problem. Adsorption-based methods are simple, efficient, and broadly used to eliminate heavy metals. Conventional adsorption materials have the problems of secondary environmental contamination. Hydrogels are considered effective adsorbents, and those prepared from biopolymers are biocompatible, biodegradable, non-toxic, safe to handle, and increasingly used to adsorb heavy metal ions.

AIM OF REVIEW

The natural origin and easy degradability of biopolymer hydrogels make them potential for development in environmental remediation. Its water absorption capacity enables it to efficiently adsorb various pollutants in the aqueous environment, and its internal pore channels increase the specific surface area for adsorption, which can provide abundant active binding sites for heavy metal ions through chemical modification.

KEY SCIENTIFIC CONCEPT OF REVIEW

As the most representative of biopolymer hydrogels, polysaccharide-based hydrogels are diverse, physically and chemically stable, and can undergo complex chemical modifications to enhance their performance, thus exhibiting superior ability to remove contaminants. This review summarizes the preparation methods of hydrogels, followed by a discussion of the main categories and applications of polysaccharide-based biopolymer hydrogels.

Comparison of visibility of iodinated hydrogel and gadolinium-modified hyaluronic acid spacer gels on computed tomography and onboard imaging

Background and purpose

In accelerated partial breast irradiation (APBI), accurate definition of the tumour bed is crucial to reduce the risk of local recurrence and the volume of healthy tissue irradiated. Recently, hydrogels have been proposed to improve visibility of the lumpectomy cavity for APBI. The aim of this study was to alter two commercially available hyaluronic acid (HA) gels, with gadopentenate dimeglumine (GD), a magnetic resonance imaging (MRI) contrast agent. We hypothesize that after injection in the surgical cavity, the mixtures will be visible with computed tomography (CT) for improved treatment planning, cone-beam CT (CBCT) for improved patient setup and planar kilovoltage (kV) x-ray for real-time tracking during treatment.

Materials and methods

In this ex vivo study, GD was mixed with the two HA gels, and 1 mL of each mixture was injected into fatty and muscular tissue of a pork phantom. Visibility with CT, CBCT and planar x-ray imaging was assessed. Contrast-to-noise ratios (CNR) were measured and compared to commercially available iodinated polyethylene glycol (PEG).

Results

The gel mixtures showed increased visibility over HA gels without GD. When comparing CNR of the gel mixtures to that of iodinated PEG on CT, there was a 4-fold increase in muscle for both mixtures and a 1.6-fold to 3.6-fold increase in fat, depending on the HA gel. Gel mixtures showed better visibility with planar kV imaging over iodinated PEG.

Conclusion

Addition of GD to HA gels increases visibility with CT, CBCT and planar x-ray imaging, indicating potential for improved delineation and positioning in APBI.