Optimizing antiemetic treatment for chemotherapy-induced nausea and vomiting in Japan: Update summary of the 2015 Japan Society of Clinical Oncology Clinical Practice Guidelines for Antiemesis.

Patients with cancer should appropriately receive antiemetic therapies against chemotherapy-induced nausea and vomiting (CINV). Antiemetic guidelines play an important role in managing CINV. Accordingly, the first Japanese antiemetic guideline published in 2010 by the Japan Society of Clinical Oncology (JSCO) has considerably aided Japanese medical staff in providing antiemetic therapies across chemotherapy clinics. With the yearly advancements in antiemetic therapies, the Japanese antiemetic guidelines require revisions according to published evidence regarding antiemetic management worldwide. A revised version of the first antiemetic guideline that considered several upcoming evidences had been published online in 2014 (version 1.2), in which several updated descriptions were included. The 2015 JSCO clinical practice guideline for antiemesis (version 2.0) (in Japanese) has addressed clinical antiemetic concerns and includes four major revisions regarding (1) changes in emetogenic risk categorization for anti-cancer agents, (2) olanzapine usage as an antiemetic drug, (3) the steroid-sparing method, and (4) adverse drug reactions of antiemetic agents. We herein present an English update summary for the 2015 JSCO clinical practice guideline for antiemesis (version 2.0).

[Elucidation of Influential Factors on Nausea Associated with Olaparib Administration].

Olaparib, an anticancer drug, requires daily administration, frequently causing nausea. Elucidation of the influential factors for nausea is important for continuing treatment. We retrospectively examined 23 patients who received olaparib treatment and were divided into nausea and no-nausea groups, according to antiemetic prescriptions during treatment. We compared the patients' background and laboratory values between the 2 groups. Nine patients developed nausea and 14 did not, with mean body weights at treatment initiation of 49.9±9.8 kg and 60.0±13.9 kg, respectively. Body weights were significantly lower in the nausea than in the no-nausea group. Four weeks after olaparib administration, the logarithmic difference in the fluctuation of the neutrophil count was -0.145±0.154 and 0.095±0.242, while the fluctuation of the lymphocyte count was -0.169±0.053 and -0.060±0.110 in the nausea and no-nausea groups, respectively, with the former significantly lower than the latter. The treatment period for the nausea group was significantly longer than that for the no-nausea group. Since olaparib is administrated as a flat dose, the dose per body weight increased in underweight patients. Thus, being underweight might have impacted the efficacy of olaparib, including the development of side effects such as nausea and hematotoxicity.

Chemotherapy for alpha-fetoprotein producing gastric cancers expressing human epidermal growth factor receptor 2.

Although, gastric cancer is one of the most common cancers worldwide, alpha-fetoprotein (AFP) producing human epidermal growth factor receptor 2 (HER2) positive gastric cancers are rare. AFP producing gastric cancer has a poor prognosis and an appropriate treatment option has not been established to date. A 75-year-old woman with AFP- producing gastric cancer was treated with S-1, an oral fluoropyrimidine derivative, chemotherapy after distal gastrectomy. Recurrence of gastric cancer was observed after 18 months and immunohistochemistry analysis showed AFP and HER2 positive gastric cancer. The patient received combination therapy containing capecitabine, cisplatin, and trastuzumab. Computed tomography scans showed regression of the lymph node metastasis. The patient's quality of life substantially improved after the treatment. Thus, the present case suggests that AFP and HER2 positive gastric cancer can be effectively treated with, capecitabine, cisplatin, and trastuzumab combination therapy.

Gemcitabine enhances rituximab-mediated complement-dependent cytotoxicity to B cell lymphoma by CD20 upregulation.

Although rituximab, a chimeric monoclonal antibody that specifically binds to CD20, has significantly improved the prognosis for diffuse large B cell lymphoma (DLBCL), one-third of DLBCL patients demonstrate resistance to rituximab or relapse after rituximab treatment. Thus, a novel approach to rituximab-based treatment is likely to be required to improve the efficacy of DLBCL treatment. As complement dependent cytotoxicity (CDC) is a key mechanism mediating rituximab's tumoricidal activity, rituximab binding to CD20 on tumor cells is a critical factor for effective rituximab-based treatments against DLBCL. We found that gemcitabine (GEM), but not lenalidomide (LEN) or azacitidine (AZA), can upregulate CD20 expression in TK and KML-1 cells, two human DLBCL cell lines. Treatment of TK and KML-1 cells with GEM enhanced CD20 expression at both the mRNA and protein levels. CD20 upregulation by GEM treatment was accompanied by increased rituximab binding to CD20. In TK cells, GEM treatment synergistically increased rituximab-mediated CDC activity in a dose-dependent manner. In KML cells, GEM treatment also induced upregulation of complement regulatory proteins, possibly leading to resistance to CDC. Treatment with LEN, a drug that did not upregulate CD20, did not enhance rituximab-mediated CDC activity. GEM treatment activated nuclear factor-kappa B (NF-kB) signaling in these cells. Furthermore, a specific inhibitor to NF-kB suppressed GEM-induced CD20 upregulation, indicating that GEM-induced NF-kB activation is closely associated with CD20 upregulation. These results suggest that when used in combination, GEM might enhance the antitumor efficacy of rituximab against DLBCL due to its unique ability to upregulate CD20.

Up-regulation of HER2 by gemcitabine enhances the antitumor effect of combined gemcitabine and trastuzumab emtansine treatment on pancreatic ductal adenocarcinoma cells.

BACKGROUND: Although pancreatic ductal adenocarcinomas (PDAs) widely express HER2, the expression level is generally low. If HER2 expression in PDA cells could be enhanced by treatment with a given agent, then combination therapy with that agent and trastuzumab emtansine (T-DM1), a chemotherapeutic agent that is a conjugate of trastuzumab, might lead to significant antitumor effects against PDA. METHODS: Cell proliferation was examined by spectrophotometry. HER2 expression was examined by flow cytometry, immunoblot and quantitative reverse transcription polymerase chain reaction. T-DM1 binding to cells was examined by flow cytometry and enzyme-linked immunosorbent assay. RESULTS: Out of 5 tested human PDA cell lines, including MIA PaCa-2, three showed increases in HER2 expression after gemcitabine (GEM) treatment. The binding of T-DM1 to GEM-treated MIA PaCa-2 cells was higher than to untreated MIA PaCa-2 cells. Treatment with GEM and T-DM1 showed synergic cytotoxic effects on MIA PaCa-2 cells in vitro. Cells in the G2M phase of the cell cycle were retained after GEM treatment and showed higher levels of HER2 expression, possibly contributing to the synergic effect of GEM and T-DM1. CONCLUSIONS: Combined treatment with GEM and T-DM1 might confer a potent therapeutic modality against PDA as a result of GEM-mediated HER2 up-regulation.

[The survey for anti-emetic guideline by using questioner].

BACKGROUND: Japan Society of Clinical Oncology published a guideline for anti-emetic therapy two years ago. This guideline was a first evidence based guideline of anti-emetic treatment for the patients who received chemotherapy in Japan. To investigate a current situation of anti-emetic treatment in Japan, we analyzed the data from nationwide questionnaire. MATERIAL: Questionnaire analysis; From June 2012 to August 2012, we gave 24 questionnaires on the Japan Society of Clinical Oncology Website and collected the response from the member of 5 major academic oncology societies. The questionnaires included degree of recognition, penetration, usefulness, problems and user type of medial stuff for the anti-emetic guideline published by (JSCO). RESULTS: Questionnaire; 1,529 medical stuff responded to our questionnaire. 1,308 (85.5%) stuffs recognized JSCO guidelines, 586 (51%) had regard for guideline and 489 (42.6%) referred to the guideline. 899 (78.3%) changed their practice in clinic to recommended practice by the guideline. But 385 (33.5%) complained high medical cost of recommended anti-emetic therapy. CONCLUSIONS: Degree of recognition and penetration of our guideline for anti-emetic therapy were very high in Japan.

Vaccination with vascular progenitor cells derived from induced pluripotent stem cells elicits antitumor immunity targeting vascular and tumor cells.

Vaccination of BALB/c mice with dendritic cells (DCs) loaded with the lysate of induced vascular progenitor (iVP) cells derived from murine-induced pluripotent stem (iPS) cells significantly suppressed the tumor of CMS-4 fibrosarcomas and prolonged the survival of CMS-4-inoculated mice. This prophylactic antitumor activity was more potent than that of immunization with DCs loaded with iPS cells or CMS-4 tumor cells. Tumors developed slowly in mice vaccinated with DCs loaded with iVP cells (DC/iVP) and exhibited a limited vascular bed. Immunohistochemistry and a tomato-lectin perfusion study demonstrated that the tumors that developed in the iVP-immunized mice showed a marked decrease in tumor vasculature. Immunization with DC/iVP induced a potent suppressive effect on vascular-rich CMS-4 tumors, a weaker effect on BNL tumors with moderate vasculature, and nearly no effect on C26 tumors with poor vasculature. Treatment of DC/iVP-immunized mice with a monoclonal antibody against CD4 or CD8, but not anti-asialo GM1, inhibited the antitumor activity. CD8(+) T cells from DC/iVP-vaccinated mice showed significant cytotoxic activity against murine endothelial cells and CMS-4 cells, whereas CD8(+) T cells from DC/iPS-vaccinated mice did not. DNA microarray analysis showed that the products of 29 vasculature-associated genes shared between genes upregulated by differentiation from iPS cells into iVP cells and genes shared by iVP cells and isolated Flk-1(+) vascular cells in CMS-4 tumor tissue might be possible targets in the immune response. These results suggest that iVP cells from iPS cells could be used as a cancer vaccine targeting tumor vascular cells and tumor cells.

[The current status of home palliative care for patients with advanced cancer at the Jikei University School of Medicine].

Medical oncologists are involved in cancer chemotherapy as well as end-of-life care. Recently, an increased number of patients with advanced cancer have expressed their preference to receive palliative care at their home during the end-of-life period, and several home medical care providers have aimed to provide such a service. The number of cancer patients who wish to receive home palliative care has also increased at our institution. We reviewed the characteristics of advanced cancer patients who received chemotherapy and who eventually received homecare from 2012 to 2014. The total number of patients was 22. Of these, 9 had breast cancer(40.9%)and 8 had colorectal cancer(36.4%). The median age was 68(range 36-90) years. Half of these patients died at home. The median duration of homecare to death was 64.5(range 12-252)days. Approximately 70% of patients were able to remain at home for over a month, but 3 patients died within 2 weeks at home and 1 patient returned to the hospital after 10 days of homecare due to disease progression. While palliative care in the home setting is valued by many cancer patients in the end-of-life period, close monitoring is needed for patients with rapidly progressing disease.

Complete response of esophageal small cell carcinoma amrubicin treatment.

Small cell carcinoma of the esophagus (SmCCE) is a rare and aggressive disease known to have a poor prognosis. SmCCE patients are generally treated with a chemotherapeutic regimen for small cell lung cancer. Salvage therapy for patients with relapsed or refractory tumors has not yet been established. A 63-year-old man with extensive SmCCE was treated with chemotherapy consisting of cisplatin (CDDP) and irinotecan (CPT-11). After the second course of CPT-11/CDDP, the celiac lymph node increased in size. Amrubicin (AMR) as second-line chemotherapy was started. The patient had a complete response after the fifth course of AMR, resulting in an 8-month progression-free survival after initial administration. This case suggests that, as in small cell lung cancer, AMR is effective for SmCCE.

Gemcitabine enhances Wilms' tumor gene WT1 expression and sensitizes human pancreatic cancer cells with WT1-specific T-cell-mediated antitumor immune response.

Wilms' tumor gene (WT1), which is expressed in human pancreatic cancer (PC), is a unique tumor antigen recognized by T-cell-mediated antitumor immune response. Gemcitabine (GEM), a standard therapeutic drug for PC, was examined for the regulation of WT1 expression and the sensitizing effect on PC cells with WT1-specific antitumor immune response. Expression of WT1 was examined by quantitative PCR, immunoblot analysis, and confocal microscopy. Antigenic peptide of WT1 presented on HLA class I molecules was detected by mass spectrometry. WT1-specific T-cell receptor gene-transduced human T cells were used as effecter T cells for the analysis of cytotoxic activity. GEM treatment of human MIAPaCa2 PC cells enhanced WT1 mRNA levels, and this increase is associated with nuclear factor kappa B activation. Tumor tissue from GEM-treated MIAPaCa2-bearing SCID mice also showed an increase in WT1 mRNA. Some human PC cell lines other than MIAPaCa2 showed up-regulation of WT1 mRNA levels following GEM treatment. GEM treatment shifted WT1 protein from the nucleus to the cytoplasm, which may promote proteasomal processing of WT1 protein and generation of antigenic peptide. In fact, presentation of HLA-A*2402-restricted antigenic peptide of WT1 (CMTWNQMNL) increased in GEM-treated MIAPaCa2 cells relative to untreated cells. WT1-specific cytotoxic T cells killed MIAPaCa2 cells treated with an optimal dose of GEM more efficiently than untreated MIAPaCa2 cells. GEM enhanced WT1 expression in human PC cells and sensitized PC cells with WT1-specific T-cell-mediated antitumor immune response.

Immunologic monitoring of cellular responses by dendritic/tumor cell fusion vaccines.

Although dendritic cell (DC)- based cancer vaccines induce effective antitumor activities in murine models, only limited therapeutic results have been obtained in clinical trials. As cancer vaccines induce antitumor activities by eliciting or modifying immune responses in patients with cancer, the Response Evaluation Criteria in Solid Tumors (RECIST) and WHO criteria, designed to detect early effects of cytotoxic chemotherapy in solid tumors, may not provide a complete assessment of cancer vaccines. The problem may, in part, be resolved by carrying out immunologic cellular monitoring, which is one prerequisite for rational development of cancer vaccines. In this review, we will discuss immunologic monitoring of cellular responses for the evaluation of cancer vaccines including fusions of DC and whole tumor cell.

[Strontium-89 therapy and subarachnoid phenol block successfully eliminated intractable pain of metastasis in the patient with advanced urachal carcinoma].

We report a case of a 39-year-old man with intractable multifocal pain caused by metastatic urachal carcinoma to the bone. The patient underwent a partial cystectomy in May 2008, and lung metastasis occurred 9 months after the surgery. He then received salvage chemotherapy, but developed metastasis to the liver, brain, and bone. He was hospitalized due to a shoulder pain, a lower back pain, buttocks pain, numbness in both legs, and drop foot in right leg. MRI revealed metastases to the spine, and lumbar spinal canal stenosis with cauda equina compression. Even a combination of fentanyl-patch, oral acetaminophen, gabapentin and paroxetine was not effective for pain control. Strontium-89 therapy and subarachnoid phenol block successfully eliminated intractable pain. The patient could be discharged from hospital and received a palliative care at home for a short period of time.

Strong impact of pathological node-negative on long-term overall survival of patients with triple-negative breast cancer receiving neoadjuvant chemotherapy.

Triple-negative breast cancer (TNBC) has a high pathological complete response (pCR) rate; however patients without a high pCR are reported to have a poor prognosis. The current study investigated the long-term overall survival of patients with TNBC who received neoadjuvant chemotherapy (NAC) and analyzed various prognostic factors including basal marker and claudin expressions. Between November 2005 and March 2012, the current study retrospectively reviewed the records of 323 patients with breast cancer who received anthracycline followed by taxane as NAC at the Jikei University Hospital Basal marker and claudin expression was determined via immunohistochemistry. The median age of the patients was 53.0 years. Of the 323 patients, 26 (8%) achieved a pCR, including 13 patients (19.7%) with TNBC and 13 (5.1%) with non-TNBC (P<0.001). Of the 66 patients with TNBC, 13 (19.7%) demonstrated recurrence and 8 (12.1%) died after a median follow-up time of 111.5 months [10-year disease-free survival (DFS), 80.3%; 95% confidence interval (CI), 0.68-0.88; 10-year overall survival (OS), 84.8%; 95% CI, 0.72-0.92]. Of the 257 patients with non-TNBC, 45 (17.5%) patients demonstrated recurrence and 26 (10.1%) died (10-year DFS, 82.1%; 95% CI, 0.76-0.87; 10-year OS, 88.6%; 95% CI, 0.83-0.92). There was no statistical difference between the patients with and without TNBC. In the TNBC group, patients with pathological node-negative status survived without distant recurrence. Additionally, negative lymphovascular infiltration was another favorable prognostic factor. Patients with TNBC who received NAC demonstrated comparably high prognoses to non-TNBC patients. Overall, pathological node status after NAC had a strong impact on the prognosis of patients with TNBC.

A Retrospective Analysis of Perioperative Chemotherapy and Coronavirus Disease in Patients With Breast Cancer.

BACKGROUND/AIM: Since January 2020, coronavirus disease (COVID-19) cases have been confirmed in Japan, and the number of patients with COVID-19 has been increasing. Two emergency declarations have been made previously and one is currently in effect. Based on our experience of a situation that could affect cancer treatment, this study retrospectively examined the correlation between perioperative anticancer therapy and COVID-19 incidence in patients with breast cancer. PATIENTS AND METHODS: Patients who underwent perioperative anticancer therapy for breast cancer at our hospital from February 2020 to February 2021 were included in this study. The presence or absence of COVID-19, timing of anticancer drug initiation, and clinical data were collected. RESULTS: No cases of COVID-19 were diagnosed in patients receiving perioperative anticancer therapy at our hospital. CONCLUSION: Regimen modification, active use of supportive care, and patient lifestyle were factors reducing the incidence of COVID-19.

Long-term outcomes of oligometastatic breast cancer patients treated with curative intent: an updated report.

BACKGROUND: Oligometastatic breast cancer (OMBC) is characterized by limited metastatic tumor numbers and sites. We have reported a 20-year overall survival (OS) rate and relapse-free rate (RFR) of 34.1% and 27.4%, respectively, in a retrospective analysis of OMBC patients treated with curative intent including a multidisciplinary approach. Metastatic breast cancer (MBC) is generally incurable; however, OMBC might be a potentially curable subset. The previous analysis included isolated locoregional recurrence (ILRR) cases, which differs from distant metastasis in treatment strategies. Therefore, in this study, we excluded ILRR cases and provided an update on clinical outcomes. We also performed a detailed subgroup analysis of OMBC patients by introducing new prognostic variables. METHODS: Data of 73 OMBC patients, including 10 ILRR cases, treated in our institution between 1980 and 2010 were retrospectively analyzed. OMBC was defined as the presence of metastatic lesions in 1-2 organs, < 5 lesions per metastasized organ, and lesion diameter < 5 cm. RESULTS: The median follow-up duration was 151 (range 12-350) months. Twenty-eight (44%) patients received local therapy. Excluding ILRR cases, the OS rates were 28.3% and 18.9% and RFRs were 26.7% at 20 and 25 years, respectively. In multivariate analysis, single-organ involvement and three or fewer metastatic lesions per organ were associated with a longer progression-free and relapse-free interval (RFI). CONCLUSIONS: Relapse-free interval reached a plateau after 20 years at approximately 25% probability. Patients with long-term survival without disease relapse are considered cured. Curative-intent therapy should be considered for OMBC patients, especially those with low tumor volume.

Dendritic/pancreatic carcinoma fusions for clinical use: Comparative functional analysis of healthy- versus patient-derived fusions.

Fetal calf serum (FCS)-independent pancreatic cancer cells were established in plasma protein fraction (PPF)-supplemented medium that is an agent of good manufacturing practice (GMP) grade. Dendritic cells (DCs) were activated with the Toll-like receptor agonist, penicillin-inactivated Streptococcus pyogenes (OK-432) that is also a GMP grade agent. Therefore, sufficient amounts of FCS-independent fusions were successfully generated with decreased potential hazards of FCS. The FCS-independent fusions expressed tumor-associated antigens, HLA-DR, costimulatory molecules, IL-12, and IL-10. Stimulation of T cells with fusions from healthy donors resulted in proliferation of T cells with high expression levels of perforin/granzyme B and IFN-gamma and efficient induction of antigen-specific cytotoxic T lymphocytes (CTLs). Selection and expansion of T-cell clones were confirmed by TCR Vbeta analysis. However, fusions from patients with metastatic pancreatic cancer induced increased expression levels of TGF-beta1 in CD4+ CD25high T cells and low levels of CTLs with decreased IFN-gamma production.

Regulation of tumor immunity by tumor/dendritic cell fusions.

The goal of cancer vaccines is to induce antitumor immunity that ultimately will reduce tumor burden in tumor environment. Several strategies involving dendritic cells- (DCs)- based vaccine incorporating different tumor-associated antigens to induce antitumor immune responses against tumors have been tested in clinical trials worldwide. Although DCs-based vaccine such as fusions of whole tumor cells and DCs has been proven to be clinically safe and is efficient to enhance antitumor immune responses for inducing effective immune response and for breaking T-cell tolerance to tumor-associated antigens (TAAs), only a limited success has occurred in clinical trials. This paper reviews tumor immune escape and current strategies employed in the field of tumor/DC fusions vaccine aimed at enhancing activation of TAAs-specific cytotoxic T cells in tumor microenvironment.

In vitro generation of cytotoxic and regulatory T cells by fusions of human dendritic cells and hepatocellular carcinoma cells.

BACKGROUND: Human hepatocellular carcinoma (HCC) cells express WT1 and/or carcinoembryonic antigen (CEA) as potential targets for the induction of antitumor immunity. In this study, generation of cytotoxic T lymphocytes (CTL) and regulatory T cells (Treg) by fusions of dendritic cells (DCs) and HCC cells was examined. METHODS: HCC cells were fused to DCs either from healthy donors or the HCC patient and investigated whether supernatants derived from the HCC cell culture (HCCsp) influenced on the function of DCs/HCC fusion cells (FCs) and generation of CTL and Treg. RESULTS: FCs coexpressed the HCC cells-derived WT1 and CEA antigens and DCs-derived MHC class II and costimulatory molecules. In addition, FCs were effective in activating CD4+ and CD8+ T cells able to produce IFN-gamma and inducing cytolysis of autologous tumor or semiallogeneic targets by a MHC class I-restricted mechanism. However, HCCsp induced functional impairment of DCs as demonstrated by the down-regulation of MHC class I and II, CD80, CD86, and CD83 molecules. Moreover, the HCCsp-exposed DCs failed to undergo full maturation upon stimulation with the Toll-like receptor 4 agonist penicillin-inactivated Streptococcus pyogenes. Interestingly, fusions of immature DCs generated in the presence of HCCsp and allogeneic HCC cells promoted the generation of CD4+ CD25high Foxp3+ Treg and inhibited CTL induction in the presence of HCCsp. Importantly, up-regulation of MHC class II, CD80, and CD83 on DCs was observed in the patient with advanced HCC after vaccination with autologous FCs. In addition, the FCs induced WT1- and CEA-specific CTL that were able to produce high levels of IFN-gamma. CONCLUSION: The current study is one of the first demonstrating the induction of antigen-specific CTL and the generation of Treg by fusions of DCs and HCC cells. The local tumor-related factors may favor the generation of Treg through the inhibition of DCs maturation; however, fusion cell vaccination results in recovery of the DCs function and induction of antigen-specific CTL responses in vitro. The present study may shed new light about the mechanisms responsible for the generation of CTL and Treg by FCs.

[Usefulness of epidural catheter with distal subcutaneous reservoir for cancer pain control in home care services].

When an effective pain relief cannot be achieved by systemic administration of analgesics, which provide adequate pain relief for up to 70 to 90 percent of patients, alternative remedies should be offered. We reported a patient with colon cancer who was effective for pain control using an epidural catheter with subcutaneous reservoir (epidural subcutaneous catheter implantation). Four other patients with an epidural catheter with subcutaneous reservoir during 2007 to 2008 also showed significant improvement in their pain level calculating by numerical rating scale (NRS). Furthermore we were able to minimize the risk of infection for homecare. However the epidural catheter with subcutaneous reservoir should be needed not only to manage dosages of epidural morphine accurately but also to prevent the incidence of catheter obstruction by general practitioners in home care service. This solution is necessary to establish the common strict guidelines between hospital doctors and general practitioners.

Long-Term Follow-Up of Node-Negative Breast Cancer Patients Evaluated via Sentinel Node Biopsy After Neoadjuvant Chemotherapy.

BACKGROUND: Sentinel node biopsy (SNB) is used to accurately assess axillary lymph node status in patients with node-negative breast cancer. However, its use after neoadjuvant chemotherapy (NAC) is controversial. We retrospectively assessed the usefulness of SNB after NAC by comparing axillary recurrence rates and other parameters in patients with clinically node-negative breast cancer who underwent SNB after NAC or without NAC. PATIENTS AND METHODS: At our hospital, 1179 patients with clinically node-negative breast cancer underwent SNB from April 2007 to December 2013. The clinicopathological and survival data of patients who underwent SNB after NAC (the NAC group) and those who underwent SNB without NAC (the control group) were compared. Patients with a metastatic sentinel node underwent axillary lymph node dissection. RESULTS: The number of patients in the NAC and control groups was 183 (15.5%) and 996 (84.5%), respectively. At diagnosis, tumors were significantly larger in the NAC group (P < .0001). Sentinel nodes were identified in almost all patients in both groups (99.5% in the NAC group vs. 99.8% in the control group). They were nonmetastatic in 147 (80.8%) patients in the NAC group and 849 (85.5%) patients in the control group. At the median follow-up time of 51.1 months, 6 patients (0.6%) in the control group had axillary lymph node recurrence compared with no patients in the NAC group. CONCLUSION: SNB after NAC was as accurate as SNB without NAC in patients with clinically node-negative breast cancer. Axillary recurrence-free survival rates were excellent regardless of whether NAC was performed before SNB.