Margins in Breast-Conserving Surgery for Early Breast Cancer: How Much is Good Enough?

Liquid metal injected from interstitial channels for inhibiting subcutaneous hepatoma growth and improving MRI/MAT image contrast

Objective

Liquid metal (LM) nowadays is considered a new biomedical material for medical treatment. The most common application of LM in medical therapy is taking LM as a carrier for oncology therapeutics. However, the feasibility and direct effect of LM in tumor treatment are still unknown, and how to delineate the negative resection margin (NRM) of the tumor is also a crucial problem in surgery. We aimed to inject LM into interstitial channels of extremities of mice to overlay the surface of the primary tumor to investigate the effect of LM on inhibiting tumor growth and highlight the NRM of the tumor.

Methods

In this study, all 50 BALB/c-nude female mice were used to construct the transplanted HepG2-type hepatocellular carcinoma model. One week after the establishment of the model, the mice were divided into three groups, named LM group, PBS group and Control group by injecting different liquid materials into the forelimb interstitial channel of the mice. T2WI image on MRI and Magneto-acoustic tomography (MAT) were used to show the distribution of LM and PBS in vivo. The group comparisons of tumor growth and blood tests were evaluated by one-way ANOVA and post-hoc analysis. And the biocompatibility of LM to BALB/c nude mice was evaluated by histopathological analysis of LM group and control group.

Results

The volume change ratio of tumor was significantly lower in LM group than in PBS and Control group after 10 days of grouping. Compared with PBS and Control group, the main indexes of blood tests in LM group were significantly lower and close to normal level. In addition, the distribution of LM in vivo could be clearly observed under T2WI anatomic images and the crossprofile of the tumor in MAT. LM also has a obvious contrast in MRI T2WI and enhanced the amplitude of imaging signal in MAT.

Conclusion

LM may inhibit the growth of transplanted hepatoma tumor through tumor encapsulation. In vivo, tumor imaging and LM distribution imaging were achieved by MRI T2WI, which verified that LM injected with interstitial injection made the NRM of tumor more prominent and had the potential of being MRI contrast agent. At the same time, LM could also be a new conductive medium to improve the imaging quality of MAT. Moreover, LM performed mild biocompatibility.

System for image-guided resection of nonpalpable breast lesions: Proof of concept

PURPOSE

In breast-conserving surgery (BCS), the cancer is sometimes incompletely excised, leading to reduced patient survival. To pursue complete excisions, radioactive seed localization (RSL) may be used to insert an iodine-125 seed into the tumor. The seed is used as a marker for the location of the tumor during surgery. RSL does not, however, show the extent of the tumor. Based on RSL, we pursue to visualize the seed location together with the extent from diagnostic images.

METHODS

A system with two gamma-camera heads and two parallel-hole collimators was recently proposed to triangulate the location of an iodine-125 seed during BCS. In the present study, this system was extended with a range camera to visualize a sphere centered on the seed in relation to the breast. This sphere contains the entire tumor and thus defines the target volume for BCS. Physical experiments with acrylic block phantoms (thickness ranging from 3.5 to 6.5 cm) were performed to assess the absolute bias and the precision with which this sphere can be visualized.

RESULTS

When a 6.5 cm thick phantom was used, along the horizontal plane, the target volume was visualized with an absolute bias and a precision of 2.1 and 0.8 mm, respectively. Along the vertical axis (i.e., z-axis), these values were 4.2 and 2.8 mm, respectively.

CONCLUSIONS

The proposed system visualizes the target volume with an absolute bias that may be acceptable for BCS.

Radiation therapy and early breast cancer: current controversies

Radiation therapy (RT) is an important component of breast cancer treatment. RT reduces local recurrence and breast cancer mortality after breast conservation for all patients and for node-positive patients after a mastectomy. Short courses of RT over 3-4 weeks are generally as effective as longer courses. A patient subgroup where RT can be avoided after conservative surgery has not been consistently identified. A radiation boost reduces the risk of a recurrence in the breast but may be omitted for older patients with good prognosis tumours with clear margins. Axillary recurrences can take a long time to appear, with 35% occurring after 5 years. Leaving disease untreated in regional nodes is associated with reduced survival. Not all patients require radiation after neoadjuvant chemotherapy and a subsequent mastectomy. Modern RT equipment and techniques will further improve survival rates.