Endoscopic tattooing to aid tumour localisation in colon cancer: the need for standardisation

Novel endoscopic tattooing dye based on polyvinylpyrrolidone-modified polydopamine nanoparticles for labeling gastrointestinal lesions

Endoscopic tattooing is a localization technique that is particularly important for identifying gastrointestinal lesions for follow-up and subsequent treatment. However, the dyes currently used for endoscopic tattooing have a short tattooing time, high cost, and many side effects. Herein, we designed and prepared polydopamine (PDA) nanoparticles modified with polyvinylpyrrolidone (PVP) for endoscopic tattooing using a physical encapsulation method. PDA has good stability and high adhesion properties, and its stability was further enhanced after PVP modification. In vitro and in vivo tests demonstrated that PDA/PVP has good biosafety. Endoscopic tattooing with PDA/PVP in a porcine model showed that the dye could be stabilized in the digestive tract for at least 60 days. Furthermore, our research results demonstrated that PDA/PVP has excellent reactive oxygen species (ROS) and reactive nitrogen species (RNS) scavenging ability and can promote wound healing. Overall, the strategy proposed herein will lead to the use of an innovative dye for endoscopic tattooing of gastrointestinal lesions.

Fallibility of tattooing colonic neoplasia ahead of laparoscopic resection: a retrospective cohort study

INTRODUCTION

Precise geographical localisation of colonic neoplasia is a prerequisite for proper laparoscopic oncological resection. Preoperative endoscopic peri-tumoural tattoo practice is routinely recommended but seldom scrutinised.

METHODS

A retrospective review of recent consecutive patients with preoperative endoscopic lesional tattoo who underwent laparoscopic colonic resection as identified from our prospectively maintained cancer database with supplementary clinical chart and radiological, histological, endoscopic and theatre database/logbook interrogation.

RESULTS

Some 210 patients with 'tattooed' colonic neoplasia were identified, of whom 169 underwent laparoscopic surgery (mean age 68 years, median BMI 27.8kg/m2, male-to-female ratio 95:74). The majority of tumours were malignant (149; 88%), symptomatic (133; 79%) and proximal to the splenic flexure (92; 54%). Inaccurate colonoscopist localisation judgement occurred in 12% of cases, 60% of which were corrected by preoperative staging computed tomography scan. A useful lesional tattoo was absent in 11/169 cases (6.5%) being specifically stated as present in 104 operation notes (61%) and absent in 10 (5.9%). Tumours missing overt peritumoral tattoos intraoperatively were more likely to be smaller, earlier stage and injected longer preoperatively (p=0.006), although half had histological ink staining. Eight lesions missing tattoos were radiologically occult. Four (44%) of these patients had on-table colonoscopy, and five (55%) needed laparotomy (conversion rate 55% vs 23% overall, p<0.005) with one needing a second operation to resect the initially missed target lesion. Mean (range) operative duration and postoperative length of stay of those missing tattoos compared with those with tattoos was 200 (78-300) versus 188 (50-597) min and 15.5 (4-22) versus 12(4-70) days (p>0.05).

CONCLUSIONS

Tattoo in advance of attempting laparoscopic resection is vital for precision cancer surgery especially for radiologically unseen tumours to avoid adverse clinical consequence.

Emerging role for thymic stromal lymphopoietin-responsive regulatory T cells in colorectal cancer progression in humans and mice

Recruitment of regulatory T cells (T_regs) to tumors is a hallmark of cancer progression. Tumor-derived factors, such as the cytokine thymic stromal lymphopoietin (TSLP), can influence T_reg function in tumors. In our study, we identified a subset of T_regs expressing the receptor for TSLP (TSLPR⁺ T_regs) that were increased in colorectal tumors in humans and mice and largely absent in adjacent normal colon. This T_reg subset was also found in the peripheral blood of patients with colon cancer but not in the peripheral blood of healthy control subjects. Mechanistically, we found that this T_reg subset coexpressed the interleukin-33 (IL-33) receptor [suppressor of tumorigenicity 2 (ST2)] and had high programmed cell death 1 (PD-1) and cytotoxic lymphocyte-associated antigen 4 (CTLA-4) expression, regulated in part by the transcription factor Mef2c. T_reg-specific deletion of TSLPR, but not ST2, was associated with a reduction in tumor number and size with concomitant increase in T_H1 cells in tumors in chemically induced mouse models of colorectal cancer. Therapeutic blockade of TSLP using TSLP-specific monoclonal antibodies effectively inhibited the progression of colorectal tumors in this mouse model. Collectively, these data suggest that TSLP controls the progression of colorectal cancer through regulation of tumor-specific T_reg function and represents a potential therapeutic target that requires further investigation.

Endoscopic Preoperative Tattooing and Marking in the Gastrointestinal Tract: A Systematic Review of Alternative Methods

Background: An accurate and reliable localization of endoluminal gastrointestinal (GI) lesions is crucial, particularly during minimally invasive surgery. As an extreme consequence, a misdetected GI lesion can lead to the resection of the wrong segment, especially in colorectal surgery. A preoperative endoscopic marking is recommended in case of GI lesions, which are expected to be difficult to detect from the serosal side. In clinical practice, three preoperative endoscopic marking methods are currently used: India ink, SPOT™, and endoclips with intraoperative fluoroscopy. All of them have substantial limitations. This has encouraged research on alternative solutions. Methods: In the current systematic review, animal and clinical studies about alternative preoperative endoscopic marking methods of GI lesions were analyzed using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Results: Thirty studies were found using PubMed/MEDLINE, EMBASE/Ovid, and the Cochrane Library for the qualitative analysis. Conclusion: Although several smart solutions have been proposed and tested successfully, all of them seem to have a substantial drawback related either to scarce stability on the marking site or potential spreading on the bowel wall or diffusion into the surgical planes.

An advanced RFID-based system to localize gastric and colon cancers during laparoscopic surgery

BACKGROUND

We aimed to improve the tumor localization system using radiofrequency identification (RFID) technology used during laparoscopic surgery for gastric and colorectal cancer. To this end, we developed a detection algorithm and designed improvement for the RFID clip.

METHODS

To evaluate the proposed system, a swine-based animal study was conducted, followed by experiments on porcine stomachs and colons using the EASIE-R simulator. The success rates of endoscopic clipping, detection time, and detection accuracy, which is the distance between the detection point and RFID tag, were measured.

RESULTS

Results of the in vivo swine animal study showed success in all three clippings and detections of the RFID clips. Results of the 60 RFID endoclip attempts using the EASIE-R simulator showed a total clipping success rate of 85.0% (n = 51/60; stomach, 83.3%, n = 25/30; colon, 86.7%, n = 26/30). The median detection times were 29.2 s for the stomach and 25.5 s for the colon. The median detection accuracy was 4.0 mm for the stomach and 4.5 mm for the colon.

CONCLUSIONS

We confirmed that the proposed RFID-based system showed improvements over the system of a previous study. This RFID-based system is effective at localizing gastric and colorectal tumors.

Preoperative endoscopic tattooing technique improved lymph node retrieval in rectal cancer patients receiving neoadjuvant concurrent chemoradiotherapy

Aims

To describe the clinical utility of lymph node retrieval and prognostic value of tattooing in rectal cancer (RC) patients undergoing neoadjuvant concurrent chemoradiotherapy (CCRT).

Methods

A total 97 RC patients underwent preoperative CCRT, and 38 patients had preoperative endoscopic tattooing. Surgical intervention was performed after CCRT and the specimens were sampled as standard protocol in all patients. Other clinicopathological parameters correlated with lymph node retrieval status were also analysed.

Results

Fifteen patients (39.5%) of 38 RC patients in the tattooing group (TG) had adequate lymph node retrieval (>12) compared with 12 (20.3%) of 59 in the non-tattooing group. Higher lymph node retrieval rate was noted in the TG (p=0.04). In multivariable analysis, it showed tattooing was an independent predictive factor for higher lymph node retrieval in RC patients after CCRT (p=0.024) by logistic regression modelling. Besides histological grade, positive lymphovascular invasion, presence of lymph node metastasis, poor CCRT response and advanced pathological stage, inadequate lymph node retrieval was significantly associated with poor survival (all p<0.05) by Kaplan-Meier analysis. In multivariable analyses, the results revealed that lymph node retrieval (p=0.005), pathological stage (p=0.001) and tumour progression grade (p=0.02) were independent prognostic markers in RC patients receiving CCRT.

Conclusion

Preoperative endoscopic tattooing is a useful technique for RC patient receiving neoadjuvant CCRT. It can improve lymph node retrieval and provide an adequate diagnosis for proper treatment and prognosis.