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

The research team, led by Chenrui Pan, Bingjie Yang and Huiming Shen as joint first authors under corresponding author Jia Li, focused on contrast-enhanced ultrasound, or CEUS. Unlike conventional ultrasound, which relies on the natural reflectivity of tissues, CEUS injects microbubble contrast agents into the bloodstream. These bubbles, far smaller than red blood cells, course through the tumor’s vasculature and echo sound waves back to the probe, allowing clinicians to watch blood flow through a lesion in real time. Because a tumor’s blood supply is one of the most intimate records of its biology, encoding how it grows, invades and dies, the technique offers a dynamic portrait of tumor physiology that static images cannot match. The researchers asked a deceptively simple question: could the vascular fingerprint of a breast tumor, captured before a single dose of chemotherapy, predict the pattern in which that tumor would later shrink?

To answer it, the team retrospectively analyzed 64 breast cancer patients who underwent neoadjuvant chemotherapy followed by surgery between June 2018 and May 2023 at their institution. After the operations, pathologists examined the removed tissue and sorted the patients into two groups according to their tumor shrinkage pattern, or TSP. Thirty-eight patients, 59.4 percent of the cohort, showed concentric shrinkage, the inward, uniform contraction that leaves a discrete residual tumor border. The remaining 26 patients, 40.6 percent, showed non-concentric shrinkage, the scattered, irregular response that complicates surgical planning. This postoperative pathology served as the ground truth against which the pretreatment imaging and clinical data were tested.

Before treatment began, each patient’s tumor was characterized with both qualitative and quantitative CEUS parameters alongside a panel of clinical features. The quantitative measures included time to peak, abbreviated TTP, which records how quickly the contrast agent reaches its maximum concentration within the lesion, a direct readout of vascular density and perfusion efficiency. The qualitative assessments included the presence of penetrating vessels, arteries that plunge from surrounding tissue into the tumor body and feed its core. The clinical variables spanned the familiar molecular markers of breast oncology: estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2, or HER2, the driver protein targeted by some of the most effective drugs in modern breast cancer therapy.

Using univariable and multivariate logistic regression, the researchers distilled this collection of variables down to four independent predictors of the shrinkage pattern: progesterone receptor status, HER2 status, time to peak on contrast-enhanced ultrasound, and the presence of penetrating vessels. Each survived statistical scrutiny with a P value below 0.05, meaning the associations were unlikely to have arisen by chance. The combination is biologically coherent. Hormone receptor and HER2 status define the tumor’s molecular subtype, which shapes how it responds to cytotoxic and targeted drugs. Perfusion kinetics and penetrating vessel architecture, meanwhile, describe the tumor’s plumbing, the delivery network that determines whether chemotherapy reaches every corner of the lesion at lethal concentrations. A tumor with sluggish perfusion or a chaotic, invasive vascular supply may respond in a patchwork fashion, dying here and persisting there, while a well-perfused tumor may contract as a coherent whole.

From these four predictors, the team constructed a nomogram, a graphical scoring tool that assigns weighted points to each variable and sums them into a probability estimate. Such tools are prized in clinical medicine because they translate complex multivariate statistics into something a clinician can use at the bedside. When the researchers tested the nomogram’s discriminatory power using receiver operating characteristic analysis, the results were striking. The area under the curve reached 0.910, with a 95 percent confidence interval of 0.835 to 0.984, placing the model well above the 0.5 threshold of random guessing and into the range considered clinically useful. In practical terms, the tool achieved a sensitivity of 81.6 percent, correctly identifying most patients destined for concentric shrinkage, and a specificity of 88.5 percent, correctly flagging most of those whose tumors would shrink non-concentrically.

The clinical stakes of this prediction are considerable. Breast-conserving surgery, which removes the tumor with a margin of healthy tissue while sparing the rest of the breast, has become the preferred operation for many early-stage patients because it preserves body image and avoids the physical and psychological burden of mastectomy. But when chemotherapy has shrunk a tumor non-concentrically, the residual disease may be scattered in strands and nests far from the original lesion’s apparent border. Operating on the assumption of concentric shrinkage in such a patient risks leaving malignant cells behind, a local recurrence waiting to happen. Conversely, patients whose tumors are predicted to shrink concentrically may be counseled with greater confidence that breast conservation is feasible. A pretreatment forecast of shrinkage pattern gives the surgical team a head start on that conversation, months before the pathology report arrives.

The study’s reliance on pretreatment imaging is what sets it apart from much of the existing literature. Many predictive models in neoadjuvant breast cancer care depend on mid-treatment assessments, requiring clinicians to wait for one or more chemotherapy cycles before imaging can offer guidance. A model built entirely from pretreatment CEUS and baseline clinical features can inform the very first treatment-planning discussion, potentially influencing the choice of surgical strategy, the sequencing of therapy, and even the design of clinical trials that stratify patients by expected response pattern. The technique itself is also widely available and comparatively inexpensive, since contrast-enhanced ultrasound is performed with standard ultrasound equipment and does not involve ionizing radiation, an advantage over repeated CT or MRI-based monitoring.

As with any retrospective study of 64 patients at a single center, the findings require validation in larger, multi-institutional cohorts before they can reshape clinical guidelines. The authors themselves note that the work was approved by the ethics committee of Zhongda Hospital and funded by the Jiangsu Provincial Commission of Health and Family Planning, and the article was published open access on 29 September 2026. Still, the convergence of molecular markers and vascular imaging into a single predictive framework points toward a broader shift in oncology: the idea that the answer to how a tumor will respond is already written into its biology, waiting to be read. With microbubbles, a probe and a well-trained eye, clinicians may soon peer into that biology before the first infusion, and plan surgery around a future they can see coming.

Subject of Research: Predicting breast cancer tumor shrinkage patterns after neoadjuvant chemotherapy using pretreatment contrast-enhanced ultrasound and clinical features

Article Title: Prediction of tumor shrinkage patterns to neoadjuvant chemotherapy based on pretreatment contrast-enhanced ultrasound and clinical features in breast cancer

Article References: Pan, C., Yang, B., Shen, H., Wang, Y., Han, J., & Li, J. (2026). Prediction of tumor shrinkage patterns to neoadjuvant chemotherapy based on pretreatment contrast-enhanced ultrasound and clinical features in breast cancer. BMC Medical Imaging. https://doi.org/10.1186/s12880-026-02837-8

Image Credits: AI Generated

DOI: 10.1186/s12880-026-02837-8

Keywords: breast cancer, neoadjuvant chemotherapy, contrast-enhanced ultrasound, tumor shrinkage patterns, breast-conserving surgery, nomogram, HER2, progesterone receptor, time to peak, penetrating vessels, predictive markers, oncology

The stakes of the question are considerable. Multi-agent neoadjuvant therapy, meaning chemotherapy given before surgery, combined with the immune checkpoint inhibitor pembrolizumab, is the established standard for Stage II and III triple-negative breast cancer. That standard rests largely on the landmark KEYNOTE-522 trial, which showed that adding immunotherapy to neoadjuvant chemotherapy improved pathologic complete response rates, event-free survival, and overall survival. But the pivotal trials that cemented this approach either excluded patients with Stage I disease or failed to analyze them separately, leaving clinicians without direct evidence for the smallest tumors. Current National Comprehensive Cancer Network guidelines still recommend upfront surgery followed by adjuvant chemotherapy for node-negative tumors measuring one to two centimeters, reserving neoadjuvant strategies for higher-risk cases.

In practice, however, the lines are blurring. Neoadjuvant therapy offers real advantages: it tests a tumor’s chemosensitivity in the body, can shrink cancers enough to enable breast-conserving surgery, and provides a powerful prognostic signal. Patients who achieve a pathologic complete response, defined as no residual invasive disease at surgery, have excellent outcomes, while those with residual disease can be escalated to treatments such as adjuvant capecitabine, validated in the CREATE-X trial, or olaparib for patients with germline BRCA mutations, validated in the OlympiA trial. These residual-disease-directed strategies have given clinicians a practical reason to give therapy up front even when a tumor is small, since the response itself guides what happens next.

To map the contemporary landscape, the researchers assembled a cohort of 252 patients with T1-2N0M0 triple-negative breast cancer diagnosed between July 2021 and December 2024, then focused on a predefined small TNBC group of 215 patients: 154 with Stage I disease and 61 with node-negative Stage II tumors smaller than three centimeters. The cohort was demographically typical of triple-negative disease, with 82.5 percent grade 3 histology and 89.3 percent ductal histology. Overall, 70.6 percent of patients received neoadjuvant therapy, 98.8 percent underwent surgery, and 42.1 percent received adjuvant radiation. With a median follow-up of 2.6 years, recurrence occurred in 18 patients and death in 11, reflecting the generally favorable prognosis of small, node-negative tumors.

The most striking finding was the asymmetry between biology and treatment. Demographically, the Stage I and small Stage II groups were nearly indistinguishable, with similar ages, menopausal status, comorbidities, and BRCA mutation prevalence. Histopathologically they overlapped as well, although grade 3 histology was more common in the Stage II, under-three-centimeter group. Yet treatment diverged sharply. Neoadjuvant therapy was given to 85.2 percent of small Stage II patients versus 61.0 percent of Stage I patients. The KEYNOTE-522 regimen, combining chemotherapy with pembrolizumab, dominated both groups but was used far more often in Stage II disease, at 75.0 percent versus 45.7 percent. Adjuvant pembrolizumab followed the same pattern, given to 56.8 percent of small Stage II patients compared with 24.7 percent of Stage I patients.

Despite these markedly different treatment intensities, outcomes converged. Recurrence rates were 6.5 percent in the small Stage II group versus 3.3 percent in Stage I, and mortality rates were 1.9 percent versus 6.6 percent, neither difference statistically significant. Among the 146 patients treated with neoadjuvant therapy, the pathologic complete response rate was 51.3 percent overall, and it was essentially identical across the stage boundary: 51.1 percent for Stage I versus 51.9 percent for small Stage II tumors. No individual regimen separated itself from the pack. KEYNOTE-522 achieved a pCR rate of 52.4 percent in the combined small TNBC cohort, statistically indistinguishable from anthracycline-taxane regimens at 50.0 percent, carboplatin-taxane plus pembrolizumab at 45.8 percent, and other neoadjuvant approaches at 55.0 percent.

Survival analyses told a similar story of convergence. Event-free survival did not differ significantly between patients who received neoadjuvant therapy and those who did not within the small TNBC cohort, nor between Stage I and small Stage II patients treated with neoadjuvant therapy. Even within the KEYNOTE-522-treated subgroup, event-free survival did not significantly differ by stage. The authors caution that these survival findings are exploratory, limited by short follow-up, few events, and the selection biases inherent in any retrospective design. Treatment assignment was not randomized, and confounding by indication, in which sicker-appearing patients receive more intensive therapy, cannot be excluded. Subgroups were also small, precluding robust multivariable modeling.

Still, the pattern is clinically meaningful. The authors note that immune checkpoint inhibitors can produce durable endocrinopathies such as adrenal insufficiency or insulin-dependent diabetes, toxicities that weigh heavily in patients whose tumors already carry a favorable prognosis. Intensifying therapy for a two-centimeter node-negative tumor while withholding the same regimen from a 2.1-centimeter tumor, purely because it crosses an arbitrary size threshold, may not reflect underlying biology. The data suggest that node-negative tumors just below and above the two-centimeter T1c-T2a boundary may behave more alike than staging conventions assume, and that a size-based framework for small triple-negative breast cancer could better contextualize treatment decisions than the current stage-based one.

The study team is already moving toward prospective answers. Their center is conducting DETENTE-1, a phase 2 randomized pilot study in Stage I triple-negative breast cancer comparing three neoadjuvant strategies: carboplatin plus paclitaxel, carboplatin plus paclitaxel plus pembrolizumab, and pembrolizumab monotherapy. Such de-escalation trials could identify which small tumors truly need intensified chemoimmunotherapy and which can be spared its costs. The authors envision integrated risk-stratification models incorporating tumor size, genomic data, immune biomarkers, toxicity risk, and cost considerations to individualize neoadjuvant selection. For now, the message for patients and clinicians is nuanced: small node-negative triple-negative breast cancers respond to modern therapy at high rates and with low recurrence, but the evidence base for choosing among regimens remains thin, and the conventional stage boundary may be a poorer guide to biology than anyone assumed.

Subject of Research: Neoadjuvant therapy patterns and outcomes in small node-negative triple-negative breast cancer

Article Title: Contemporary therapy for small node-negative triple-negative breast cancer: a retrospective cohort study

Article References: Lee, B., Santos, B., McArthur, H., LeVee, A., Kordic, A., Zhang, S., & J. Gruber, J. (2026). Contemporary therapy for small node-negative triple-negative breast cancer: a retrospective cohort study. Breast Cancer Research and Treatment, 219(3), Article 15. https://doi.org/10.1007/s10549-026-08074-5

Image Credits: AI Generated

DOI: 10.1007/s10549-026-08074-5

Keywords: triple-negative breast cancer, neoadjuvant therapy, pembrolizumab, KEYNOTE-522, pathologic complete response, Stage I breast cancer, immunotherapy, cancer staging, treatment de-escalation, retrospective cohort study, event-free survival, breast-conserving surgery