Lympho-vascular invasion impacts the prognosis in breast-conserving surgery: a systematic review and meta-analysis

Background It is estimated that breast cancer (BC) incidence, especially that of early-stage breast cancer cases continues to rise due to increased universal screening. Breast-conserving surgery (BCS) is the main intervention for early-stage BC. Lympho-vascular invasion (LVI) is reported to influence breast cancer prognosis but its prognostic value in breast-conserving treatment is controversial. Methods A search was conducted on the Cochrane library, PubMed, Web of Science, and EMBASE from inception to December 1st, 2021, without language restrictions, to identify studies that explored the prognosis of lympho-vascular invasion in breast-conserving surgery. Reviews of each study were conducted, and data extracted. The meta-analysis was performed with StataSE 16. Study quality assessment was evaluated using the Newcastle–Ottawa Scale. Results Overall, 15 studies with 21,704 patients deemed eligible for this study. Event-free survival (EFS), disease-free survival (DFS), overall survival (OS), distant metastases (DM), loco-regional recurrence (LRR), local recurrence (LR), breast recurrence (BR), disease specific survival (DSS), and breast cancer specific survival (BCSS), were extracted from each study. We found that LVI leads to poor OS (HR = 1.46, 95% CI: 1.17–1.83), DM (HR = 2.08, 95% CI: 1.66–2.60) and LR (HR = 2.00, 95% CI: 1.54–2.61). Conclusions We confirmed that early-stage BC patients with LVI-positive have poorer OS, DFS, LRR, BCSS, DM and LR following receiving BCS than those LVI-negative patients. Mastectomy, in combination with radical systemic therapies could be considered, especially in those requiring second surgery. How to change the impact of LVI on the local recurrence rate and long-term survival in patients who undergo BCS may be a valuable research direction in the future. Supplementary Information The online version contains supplementary material available at 10.1186/s12885-022-09193-0.

Specify the methods used to collect data from reports, including how many reviewers collected data from each report, whether they worked independently, any processes for obtaining or confirming data from study investigators, and if applicable, details of automation tools used in the process.

5, 6
Data items 10a List and define all outcomes for which data were sought. Specify whether all results that were compatible with each outcome domain in each study were sought (e.g. for all measures, time points, analyses), and if not, the methods used to decide which results to collect.

10b
List and define all other variables for which data were sought (e.g. participant and intervention characteristics, funding sources). Describe any assumptions made about any missing or unclear information.

5
Study risk of bias assessment 11 Specify the methods used to assess risk of bias in the included studies, including details of the tool(s) used, how many reviewers assessed each study and whether they worked independently, and if applicable, details of automation tools used in the process.

5
Effect measures 12 Specify for each outcome the effect measure(s) (e.g. risk ratio, mean difference) used in the synthesis or presentation of results.

5
Synthesis methods 13a Describe the processes used to decide which studies were eligible for each synthesis (e.g. tabulating the study intervention characteristics and comparing against the planned groups for each synthesis (item 5)).

No. Item Location where item is reported
13b Describe any methods required to prepare the data for presentation or synthesis, such as handling of missing summary statistics, or data conversions.

5, 6
13c Describe any methods used to tabulate or visually display results of individual studies and syntheses.
5, Table 1 13d Describe any methods used to synthesize results and provide a rationale for the choice(s). If meta-analysis was performed, describe the model(s), method(s) to identify the presence and extent of statistical heterogeneity, and software package(s) used.

13e
Describe any methods used to explore possible causes of heterogeneity among study results (e.g. subgroup analysis, meta-regression).

5, 6, 7 13f
Describe any sensitivity analyses conducted to assess robustness of the synthesized results.

5, 6, 7
Reporting bias assessment 14 Describe any methods used to assess risk of bias due to missing results in a synthesis (arising from reporting biases).

7
Certainty assessment 15 Describe any methods used to assess certainty (or confidence) in the body of evidence for an outcome. -

Study selection 16a
Describe the results of the search and selection process, from the number of records identified in the search to the number of studies included in the review, ideally using a flow diagram.
6, Figure 1 16b Cite studies that might appear to meet the inclusion criteria, but which were excluded, and explain why they were excluded.

5, 6
Study characteristics 17 Cite each included study and present its characteristics.

OTHER INFORMATION
Registration and protocol 24a Provide registration information for the review, including register name and registration number, or state that the review was not registered.
The review was not registered. 24b Indicate where the review protocol can be accessed, or state that a protocol was not prepared.
A protocol was not prepared 24c Describe and explain any amendments to information provided at registration or in the protocol.
The review was not registered.

Support 25
Describe sources of financial or non-financial support for the review, and the role of the funders or sponsors in the review.

10
Competing interests 26 Declare any competing interests of review authors.

10
Availability of data, code and other materials 27 Report which of the following are publicly available and where they can be found: template data collection forms; data extracted from included studies; data used for all analyses; analytic code; any other materials used in the review.

Eligibility criteria 3
Specify the inclusion and exclusion criteria for the review.

Yes
Information sources 4 Specify the information sources (e.g. databases, registers) used to identify studies and the date when each was last searched.

Yes
Risk of bias 5 Specify the methods used to assess risk of bias in the included studies.

Yes
Synthesis of results 6 Specify the methods used to present and synthesize results.

Included studies 7
Give the total number of included studies and participants and summarise relevant characteristics of studies.

Yes
Synthesis of results 8 Present results for main outcomes, preferably indicating the number of included studies and participants for each. If meta-analysis was done, report the summary estimate and confidence/credible interval. If comparing groups, indicate the direction of the effect (i.e. which group is favoured).

Limitations of evidence 9
Provide a brief summary of the limitations of the evidence included in the review (e.g. study risk of bias, inconsistency and imprecision).

Yes
Interpretation 10 Provide a general interpretation of the results and important implications.

Funding 11
Specify the primary source of funding for the review.

Yes
Registration 12 Provide the register name and registration number.