Three-dimensional visual technique based on CT lymphography data combined with methylene blue in endoscopic sentinel lymph node biopsy for breast cancer

In this study, we found that our reconstructed 3D models clearly displayed all the structures of breast and axilla, which favors the intraoperative detection of SLNs. Our data demonstrated that the method of ESLNB guided by preoperative 3DVT and intraoperative methylene blue dye exhibited a high SLN identification rate of 100% (389/389), sensitivity of 93.43% (128/137) and an accuracy of 93.83% (365/389), with a relatively low false-negative rate of 6.57% (9/137). Surgical complications of upper limb lymphedema occurred in one patient during the 12-month follow-up period after surgery.

A comprehensive understanding of lymphatic drainage pathways and precise determination of the location of SLNs through preoperative examinations are critical to the success of SLNB. In this study, we applied a 3DVT based on CT-LG data combined with methylene blue to identify the SLNs, and 3D reconstruction with visual simulation surgery were conducted as routine procedures before actual surgery. With this technique, traditional two-dimensional CT data can be reconstructed into a 3D visualization model, which allows for a clear visualization of the breast structure, the spatial location of lymph nodes, and their relationship with surrounding tissues. Thus, surgeons could locate the SLNs and design surgical plans accordingly, and the position of the endoscopic incision and direction of the long syringe could also be easily determined [12]. Therefore, we consider this 3D visualization technique to offer efficient detection and accurate removal of SLNs intraoperatively.

Studies have revealed the superiority of the combined use of blue dye and radioisotopes in terms of relatively low non-identification and false-negative rates. Hence, this dual technique is currently considered the international standard method and has been recommended for SLN mapping [13, 14]. However, the radioisotope method is not extensively accessible in clinical practice. Most of medical institutions in developing countries such as China still mapping breast cancer SLNs using blue dye alone. Using blue dye as the sole tracer inevitably leads to a relatively low detection rate (89% to 95.7%) and high false-negative rate (9% to 18%), as reported in previous studies [6, 8, 15]. In terms of diagnostic accuracy of SLN, our result was similar to or even better than those of previous studies that identified SLN by indocyanine green or a conventional dual method [7, 16]. Thus, it can be said that blue dye guided by 3DVT is sufficient for SLN detection in breast cancer.

With the navigation of 3DVT and preoperative CT-LG, the present study showed a false-negative rate of 6.57% (9/137). Compared to the false-negative rates reported in other studies performing SLNB or ESLNB without the assistance of 3DVT and preoperative CT-LG, our results showed a modest reduction in the false-negative rate, which further reinforces the advantages of preoperative 3D CT-LG and visual simulation surgery [17, 18]. The reasons for the satisfactory SLN detection performance of this technique in our study are as follows. The digital 3D model reconstructed from CT-LG data is virtually identical to the patient's anatomy. These models help to determine the number and location of lymph nodes in advance, which facilitates the design of surgical plans. Due to the visualized simulation surgical procedure based on the digital 3D models, we can quickly and accurately find SLNs during surgery. This method simplifies the process of searching for SLNs and reduces the probability of omission. Therefore, applying 3DVT based on preoperative CT-LG in ESLNB results in the ability to detect and identify SLNs with a high identification rate and a relatively low false-negative rate.

In this group of patients, nine cases of false-negative results occurred with one or two positive ALNs after the final dissection. Related factors that were associated with failure of SLN identification included body mass index, size or location of the tumor, navigation technique, and surgeon experience. The last factor might explain our failure to harvest the SLNs, as all of these cases occurred during the early stage of our study. Positive SLNs might have been omitted because of insufficient experience in SLN localization based on CT-LG and intraoperative use of methylene blue dye. As the surgeons became more proficient with the procedure, no false-negative results were identified in the patients enrolled later.

During the 12-month follow-up period, one patient developed lymphedema of the upper limb 3 months after the surgery; the patient’s arm was swollen and she found it difficult to move. Complications such as limb pain, swelling, wound infection, and subcutaneous edema were not found in other patients during the 12-month follow-up period. The possible reasons for the lower incidence of lymphedema are as follows. The 3D model reconstructed based on CT-LG data allows for a clear visualization of the spatial location of lymph nodes and their relationship to the surrounding tissue. The application of 3DVT in ESLNB enables accurate detection and removal of SLNs, and helps avoid damage to additional tissues and structures in the armpit. In addition, as a less invasive procedure, ESLNB provides excellent cosmetic results by reducing the size of the operative incision and minimizing tissue trauma, which is consistent with the esthetic needs of female patients, especially those that require breast conservation or reconstruction [19, 20]. By using an endoscope, the surgical field of view is much clearer to preserve the small veins and lymphatic vessels that drain the upper limb. In this way, the occurrence of postoperative lymphedema can be minimized greatly.

Our research suggests that 3DVT enables surgeons to have a more accurate understanding of the patient’s internal anatomical structure preoperatively, which is conducive to reasonable surgical planning [21, 22]. It also plays a guiding role during the actual surgery, assisting surgeons to quickly locate SLNs and avoid damaging additional tissue, thereby reducing complications.

This study has some limitations. First, the relatively small sample size from a single institution might compromise the representativeness of the study. Second, short follow-up time and the lack of long-term efficacy tracking data do not allow further assessment of oncological outcomes. Therefore, more high quality, large-scale randomized controlled clinical trials are needed to verify the current findings.

留言 (0)

沒有登入
gif