Breast-Conserving Surgery Beats Expectations in Developing Countries, 21-Year Study Finds

Breast-conserving surgery has long been considered the gold standard for women with early-stage breast cancer, sparing patients the physical and psychological toll of full mastectomy while delivering comparable survival outcomes. Yet the operation carries a well-known technical vulnerability: if the surgeon fails to remove the tumor with a surrounding rim of healthy tissue, cancer cells may be left behind at the cut edge, known as the surgical margin. A positive margin typically forces a second operation and raises the risk of local recurrence. For decades, most of the evidence on how often this happens—and why—has come from high-income countries, leaving a striking gap in the literature for the developing world, where surgical infrastructure, pathology services, and tumor biology may differ substantially.

A new retrospective study from Tehran University of Medical Sciences, published in BMC Cancer, now offers one of the largest and longest-window assessments of margin outcomes in a developing country to date. Drawing on more than two decades of clinical records, the research team led by Sadaf Alipour, Bita Eslami, Nasim Nouri, Ramesh Omranipour, and Samareh Heydari analyzed the cases of 2,585 women who underwent breast-conserving surgery between 2003 and 2024. The scale of the dataset matters: with a median patient age of 49 years and a mean tumor diameter of 27 millimeters, the cohort captures the typical profile of breast cancer presentation in Iran, where disease often appears in younger women and at somewhat larger sizes than in Western registries.

The headline finding is unexpectedly encouraging. Histological examination of the surgical specimens revealed free, or negative, margins in 91.4 percent of cases, meaning that only 8.6 percent of patients had cancer cells extending to the edge of the removed tissue. That figure is lower than the rates reported in much of the existing international literature, where margin positivity after breast-conserving surgery has commonly been described at rates ranging from roughly 10 to 30 percent depending on the population, the definition of an adequate margin, and the era of the study. For a resource-constrained setting often assumed to face structural disadvantages in surgical oncology, the result challenges a persistent assumption that outcomes in developing countries must lag behind those of wealthier health systems.

The technical stakes of margin status are worth spelling out. When a pathologist examines the excised lumpectomy specimen, they ink the outer surfaces and section the tissue to determine whether tumor cells touch the inked edge. A positive margin means residual disease may remain in the breast, and the standard response is re-excision—a second operation to remove additional tissue from the involved cavity wall. Beyond the immediate burden of repeat anesthesia, hospitalization, and scarring, positive margins are associated with elevated rates of local recurrence, since any remaining tumor cells can seed regrowth. Guidelines from major surgical societies therefore treat a negative margin as a non-negotiable endpoint of breast-conserving therapy, and quality metrics in many countries track institutional re-excision rates as a proxy for surgical excellence.

Every patient in the Iranian cohort who had an involved margin underwent re-excision of the affected edge, the authors report, indicating that the clinical pathway for managing positive margins was consistently followed. That consistency itself is informative. In some low- and middle-income settings, fragmented referral pathways or limited pathology capacity can delay or complicate the identification of margin involvement. The Tehran experience suggests that a large academic center with integrated surgical and pathological services can achieve both a low primary positivity rate and reliable correction when positivity occurs, providing a template for other institutions in comparable health systems.

Perhaps the most clinically useful contribution of the study is its identification of preoperative predictors of margin involvement. Using both univariate and multivariate logistic regression models, the researchers examined how a range of tumor and patient characteristics related to the odds of a positive margin. Three factors emerged as significantly associated: younger patient age, larger tumor size, and the presence of lymphovascular invasion, the histological finding of tumor cells within small blood or lymphatic vessels surrounding the tumor. Each of these variables can be assessed before or at the time of surgery, which is precisely what makes them actionable.

The biology behind these associations is plausible. Younger patients tend to have denser breast parenchyma and, in some populations, more biologically aggressive tumor subtypes, which can make it harder for surgeons to gauge the extent of disease by palpation or imaging. Larger tumors occupy more volume relative to the breast and are more likely to have irregular, infiltrative borders that extend beyond what preoperative measurements suggest. Lymphovascular invasion, meanwhile, is a recognized marker of invasive behavior, indicating a propensity for tumor cells to spread along tissue planes—exactly the pattern that produces microscopic extensions past a grossly clear resection line. A surgeon who knows, before making the first incision, that a patient carries these risk factors can plan wider excision margins, request intraoperative assessment, or counsel the patient about the possibility of a second procedure.

The study’s methodology deserves attention for what it says about the reliability of the findings. By restricting inclusion to female patients with complete data and spanning a 21-year period, the investigators minimized the selection biases that often plague single-center surgical series. The long time window also implicitly captures the evolution of breast surgical technique over two decades, including the gradual adoption of oncoplastic approaches, improved preoperative imaging, and more standardized pathology protocols. The research was approved by the ethics committee of Tehran University of Medical Sciences and conducted with written informed consent under the Declaration of Helsinki, and the authors declare no competing interests, with funding provided by the university’s Deputy of Research.

For the global surgical oncology community, the implications cut in two directions. First, the data provide a benchmark against which other centers in developing countries can measure their own performance, filling a documented evidence gap that has made it difficult to design regionally appropriate quality-improvement programs. Second, the identified predictors give clinicians in any setting a simple, low-cost risk stratification tool: age, tumor size, and lymphovascular status are all routinely available from standard workups, requiring no advanced technology to apply. In health systems where re-operation carries disproportionate financial and logistical burdens for patients—many of whom travel long distances for care—preoperative risk prediction has an especially high practical value.

The study also serves as a reminder that surgical quality is not a function of national income alone. With careful technique, integrated pathology, and attention to known risk factors, breast-conserving surgery in a developing country can achieve margin outcomes that compare favorably with the best published figures. As the authors conclude, recognizing the clinical and pathological factors linked to margin involvement allows for better risk prediction and potential surgical adjustment before the operation begins—turning what has historically been a reactive, post-hoc problem into one that can be anticipated and, increasingly, prevented.

Subject of Research: Positive surgical margin rates and predictors in breast-conserving surgery for breast cancer in a developing country

Article Title: Frequency of positive margins and predictors in breast-conserving surgery in developing countries

Article References: Frequency of positive margins and predictors in breast-conserving surgery in developing countries. (n.d.). https://doi.org/10.1186/s12885-026-17073-0

Image Credits: AI Generated

DOI: 10.1186/s12885-026-17073-0

Keywords: breast cancer, breast-conserving surgery, positive surgical margin, re-excision, lymphovascular invasion, surgical oncology, Iran, risk factors, local recurrence, developing countries, tumor size, pathology