Staging and restaging of advanced esophageal cancer

Prognostic value of baseline 18F-FDG PET/CT in patients with esophageal squamous cell carcinoma treated with definitive (chemo)radiotherapy

PURPOSE

To investigate the prognostic value of baseline ¹⁸F-FDG PET/CT in patients with esophageal squamous cell carcinoma (ESCC) treated with definitive (chemo)radiotherapy.

METHODS

A total of 98 ESCC patients with cTNM stage T1-4, N1-3, M0 who received definitive (chemo)radiotherapy after ¹⁸F-FDG PET/CT examination from December 2013 to December 2020 were retrospectively analyzed. Clinical factors included age, sex, histologic differentiation grade, tumor location, clinical stage, and treatment strategies. Parameters obtained by ¹⁸F-FDG PET/CT included SUV_max of primary tumor (SUV_Tumor), metabolic tumor volume (MTV), total lesion glycolysis (TLG), SUV_max of lymph node (SUV_LN), PET positive lymph nodes (PLNS) number, the shortest distance between the farthest PET positive lymph node and the primary tumor in three-dimensional space after the standardization of the patient BSA (SD_max(LN-T)). Univariate and multivariate analysis was conducted by Cox proportional hazard model to explore the significant factors affecting overall survival (OS) and progression-free survival (PFS) in ESCC patients.

RESULTS

Univariate analysis showed that tumor location, SUV_Tumor, MTV, TLG, PLNS number, SD_{max (LN-T)} were significant predictors of OS and tumor location, and clinical T stage, SUV_Tumor, MTV, TLG, SD_{max (LN-T)} were significant predictors of PFS (all p < 0.1). Multivariate analysis showed that MTV and SD_{max (LN-T)} were independent prognostic factors for OS (HR = 1.018, 95% CI 1.006-1.031; p = 0.005; HR = 6.988, 95% CI 2.119-23.042; p = 0.001) and PFS (HR = 1.019, 95% CI 1.005-1.034; p = 0.009; HR = 5.819, 95% CI 1.921-17.628; p = 0.002). Combined with independent prognostic factors MTV and SD_{max (LN-T)}, we can further stratify patient risk.

CONCLUSIONS

Before treatment, ¹⁸F-FDG PET/CT has important prognostic value for patients with ESCC treated with definitive (chemo)radiotherapy. The lower the value of MTV and SD_{max (LN-T)}, the better the prognosis of patients.

Prospective comparison of MR with diffusion-weighted imaging, endoscopic ultrasound, MDCT and positron emission tomography-CT in the pre-operative staging of oesophageal cancer: results from a pilot study

OBJECTIVE

To compare the diagnostic performance of MR and diffusion-weighted imaging (DWI), multidetector CT, endoscopic ultrasonography (EUS) and ¹⁸F-FDG (fluorine-18 fludeoxyglucose) positron emission tomography CT (PET-CT) in the pre-operative locoregional staging of oesophageal cancer.

METHODS

18 patients with oesophageal or Siewert I tumour (9 directly treated with surgery and 9 addressed to chemo-/radiotherapy before) underwent 1.5-T MR and DWI, 64-channel multidetector CT, EUS and PET-CT before (n = 18) and also after neoadjuvant treatment (n = 9). All images were analysed and staged blindly by dedicated operators (seventh TNM edition). Two radiologists calculated independently the apparent diffusion coefficient from the first scan. Results were compared with histopathological findings. After the population had been divided according to local invasion (T1-T2 vs T3-T4) and nodal involvement (N0 vs N+), sensitivity, specificity, accuracy, positive- and negative-predictive values were calculated and compared. Quantitative measurements from DWI and PET-CT were also analysed.

RESULTS

For T staging, EUS showed the best sensitivity (100%), whereas MR showed the highest specificity (92%) and accuracy (83%). For N staging, MR and EUS showed the highest sensitivity (100%), but none of the techniques showed adequate results for specificity. Overall, MR showed the highest accuracy (66%) for N stage, although this was not significantly different to the other modalities. The apparent diffusion coefficient was different between surgery-only and chemo-/radiotherapy groups (1.90 vs 1.30 × 10^-3 mm² s^-1, respectively; p = 0.005)-optimal cut off for local invasion: 1.33 × 10^-3 mm² s^-1 (p = 0.05). Difference in standardized uptake value was also very close to conventional levels of statistical significance (8.81 vs 13.97 g cm^-3, respectively; p = 0.05)-optimal cut off: 7.97 g cm^-3 (p = 0.44).

CONCLUSION

In this pilot study, we have shown that MR with DWI could enrich the current pre-operative work-up for oesophageal cancer and could be used for T and N staging. However, larger studies will need to be carried out before introducing this technique in the standard diagnostic pathway, in order to understand if MR with DWI could change its management and replace more costly or invasive tests such as PET-CT or EUS. Advances in knowledge: This pilot study represents the first effort where the four techniques have been prospectively compared together for oesophageal cancer staging. The combination of MR and DWI could provide important, additional information for staging and initial treatment decision-making.

Impact of PET/CT on radiation treatment in patients with esophageal cancer: A systematic review

PURPOSE

With the advances in radiotracers, positron emission tomography/computed tomography (PET/CT) is recognized as a useful adjunct to anatomic imaging with CT, MRI and endoscopic ultrasonography (EUS). The objective of this review was to comprehensively analyze the roles of PET/CT for the radiotherapy of esophageal cancer.

METHODS

In this review, we focused on issues concerning the application of PET/CT in TNM staging, target volume delineation and response to therapy, both for the primary tumor and regional lymph nodes. Furthermore, the following questions were addressed: how does PET/CT guide appropriate treatment protocols, how does it allow accurate tumor delineation and how does it guide prognosis and future treatment decisions.

RESULTS AND CONCLUSION

For the staging of esophageal cancer, PET/CT played a crucial role in exploring distant malignant lymph nodes and metastasis with high sensitivity, specificity and accuracy. PET/CT using different radiotracer provided a serial of thresholding methods based on standardized uptake value (SUV) to assist in auto-contouring the gross tumor volume (GTV). The change in SUV may offer a potential paradigm of personalized treatment to definitive chemoradiotherapy (CRT). In total, PET/CT has sought to further optimize radiotherapy treatment planning for patients with esophageal cancer.

The emerging field of radiomics in esophageal cancer: current evidence and future potential

'Radiomics' is the name given to the emerging field of extracting additional information from standard medical images using advanced feature analysis. This innovative form of quantitative image analysis appears to have future potential for clinical practice in patients with esophageal cancer by providing an additional layer of information to the standard imaging assessment. There is a growing body of evidence suggesting that radiomics may provide incremental value for staging, predicting treatment response, and predicting survival in esophageal cancer, for which the current work-up has substantial limitations. This review outlines the available evidence and future potential for the application of radiomics in the management of patients with esophageal cancer. In addition, an overview of the current evidence on the importance of reproducibility of image features and the substantial influence of varying smoothing scales, quantization levels, and segmentation methods is provided.

Prognostic utility of diffusion-weighted MRI in oesophageal cancer: is apparent diffusion coefficient a potential marker of tumour aggressiveness?

PURPOSE

To investigate the role of the apparent diffusion coefficient (ADC) as a potential prognostic biomarker in the evaluation of the aggressiveness of oesophageal cancer.

MATERIALS AND METHODS

Between November 2009 and December 2013, 43 patients with evidence of oesophageal or oesophago-gastric junction cancer were referred to our institution and prospectively entered in our database. The final study population consisted of 23 patients (18 men; 5 women; mean age, 64.62 ± 10.91 years) who underwent diffusion-weighted Magnetic Resonance before surgical intervention. Specifically, 14 were directly treated with surgery and 9 were addressed to chemo/radiotherapy beforehand. Two radiologists independently measured mean tumour ADC and inter-observer agreement (Spearman's and intraclass correlation coefficient [ICC]) was assessed. In the univariate analysis, overall survival curves related to pathological ADC, pT, pN, tumour location and histotype were fitted using the Kaplan-Meier method. Survival curves were then compared using the log-rank test.

RESULTS

Inter-observer reproducibility was very good (Spearman's rho = 0.95; ICC = 0.94). At a total median follow-up of 19 months (2-49 months), 4 patients had died. The median follow-up was 18.50 months (5-49 months) for the surgery-only group (1/4 events, 25 %) and 24 months (2-34 months) for the chemo/radiotherapy group (3/4 events, 75 %). Survival time at 48 months for the overall population was 59 % (±0.11), while for the surgery-only group and the chemo/radiotherapy group was 90 % (±0.09) and 61 % (±0.34), respectively. In the univariate analysis, ADC values below or equal to 1.4 × 10(-3) mm(2)/s were associated with a negative prognosis both in the total population (P = 0.016) and in the surgery-only group (P < 0.001).

CONCLUSION

Despite the biggest limitation of our study (i.e. the small study population), we were able to show that pathological ADC could be considered a prognostic factor for oesophageal cancer. DWI might be introduced into clinical practice as a promising and reliable technique in the diagnostic pathway of this tumour.

New directions in perioperative management of locally advanced esophagogastric cancer

Cancers of the esophagus arise as adenocarcinomas and squamous cell carcinomas; these represent distinct diseases, with differing prognosis, yet they are often studied in common trials. With surgery alone, 5 year survival for T2-T3N0 disease is less than 30% to 40%, and declines to less than 25% with nodal involvement. The CROSS randomly assigned patients to surgery alone or to weekly carboplatin/paclitaxel X 5 and 41.4 Gy concurrent radiotherapy, followed by surgery. Seventy-five percent of enrolled patients had adenocarcinoma. Preoperative combined-modality therapy improved R0 resection from 69% to 92% (p &lt; 0.001 and improved median survival from 24 months to 49.4 months (p &lt; 0.003). This regimen reduced both locoregional recurrence (34% to 14%; p &lt; 0.001) and the development of peritoneal carcinomatosis (14% to 4%; p &lt; 0.001). Systemic perioperative therapy may have a greater effect on distant disease, the predominant mode of failure for these patients, and current trials compare preoperative chemoradiation with periooperative systemic therapy. PET scan response during preoperative chemotherapy without radiotherapy correlates with improvements in pathologic response and with improved survival. Nonresponse on early PET scan allows identifıcation of patients for earlier surgery and discontinuation of ineffective preoperative chemotherapy, without survival detriment. There is no predictive benefıt for early PET scan during the course of chemotherapy followed by chemoradiotherapy. The use of early PET scan during induction chemotherapy is being evaluated in CALGB/Alliance trial (NCT01333033). Molecular profıling has identifıed somatic gene mutations and pathways that may be oncogenic in upper gastrointestinal cancers. Potential targets include the epidermal growth factor receptor (EGFR), vascular endothelial growth factor receptor (VEGFR), HER2, mammalian target of rapamycin (mTOR), fıbroblast growth factor receptor (FGFR), MEK, and others. Targeted therapies with known survival benefit in esophagogastric cancer are currently limited to trastuzumab for HER2 overexpressing cancers, or ramicirumab.

Accuracy of multidetector-row CT for restaging after neoadjuvant treatment in patients with oesophageal cancer

OBJECTIVES

To assess the diagnostic accuracy of 64-multidetector CT (MDCT) for restaging of patients with oesophageal cancer undergoing neoadjuvant therapy.

METHODS

Results of pathological staging were correlated with those from 64-MDCT before and after neoadjuvant treatment in 35 patients using the American Joint Committee on Cancer/TNM classification (7th edition). CT response was determined using the Response Evaluation Criteria in Solid Tumours (RECIST) method, modified for one-dimensional tumour diameter measurement.

RESULTS

64-MDCT predicted T stage correctly in 34 % (12/35), overstaged in 49 % (17/35) and understaged in 17 % (6/35). Sensitivity/specificity values were as follows: T0, 20 %/92 %; T1-T2, 31 %/59 %; T3, 60 %/64 %; T4, 100 %/4 %. Negative predictive values for T3/T4 were 80 %/100 %. MDCT accurately predicted complete histopathological response in 20 % (accuracy 74 %) and overstaged in 80 %. Tumour regression grade was predicted correctly in only 8 % (2/25) and underestimated in 68 % (17/25). Accurate N stage was noted in 69 % (24/35).

CONCLUSION

Although MDCT tends to be able to exclude advanced tumour stages (T3, T4) with a higher likelihood, the diagnostic accuracy of high resolution MDCT for restaging oesophageal cancer and assessing the response to neoadjuvant therapy has not improved in comparison to older-generation CT. Therefore, the future assessment of oesophageal tumour response should focus on combined morphologic and metabolic imaging.

KEY POINTS

• Multidetector CT (MDCT) has been beneficial for the evaluation of many tumours. • However diagnostic accuracy for restaging oesophageal cancer has not improved with MDCT. • MDCT tends to be able to exclude advanced tumour stages (T3/T4). • MDCT has a low accuracy for determining lymph node metastasis. • Oesophageal tumour response should be assessed by combined morphological and metabolic imaging.

The new era of staging as a key for an appropriate treatment for esophageal cancer

Fluorodeoxyglucose-positron emission tomography (FDG-PET) and computed tomography (CT) have become the gold standard for staging of esophageal cancer by detecting distant metastases, but metastatic lymph nodes are often difficult to diagnose from the size and standardized uptake value (SUV). If we compare the diagnostic performance of endoscopic ultrasonography (EUS), CT, and FDG-PET in staging of esophageal cancer, EUS is the most sensitive method to identify the detection of regional lymph node metastases, whereas CT and FDG-PET are more specific tests. Combination study with CT, EUS and PETCT cannot make a precise diagnosis after neoadjuvant therapy (NAT). A precise staging might be determined by the fine needle aspiration biopsy (FNAB) under EUS and US screening in the neck and the abdomen even after NAT. Indication of endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) for superficial cancer is sensitive because of difficulty in T1b cancer diagnosis. Detailed examination about vessel invasion and the possibility of residual tumor with dissected specimen will offer an appropriate additional therapy. New strategy like sentinel lymph node (SLN) navigation could supply more information about lymphatic routes and metastatic nodes. SLN navigation with ESD might become a new less invasive strategy for superficial esophageal cancer.

Imaging strategies in the management of oesophageal cancer: what's the role of MRI?

OBJECTIVES

To outline the current role and future potential of magnetic resonance imaging (MRI) in the management of oesophageal cancer regarding T-staging, N-staging, tumour delineation for radiotherapy (RT) and treatment response assessment.

METHODS

PubMed, Embase and the Cochrane library were searched identifying all articles related to the use of MRI in oesophageal cancer. Data regarding the value of MRI in the areas of interest were extracted in order to calculate sensitivity, specificity, predictive values and accuracy for group-related outcome measures.

RESULTS

Although historically poor, recent improvements in MRI protocols and techniques have resulted in better imaging quality and the valuable addition of functional information. In recent studies, similar or even better results have been achieved using optimised MRI compared with other imaging strategies for T- and N-staging. No studies clearly report on the role of MRI in oesophageal tumour delineation and real-time guidance for RT so far. Recent pilot studies showed that functional MRI might be capable of predicting pathological response to treatment and patient prognosis.

CONCLUSIONS

In the near future MRI has the potential to bring improvement in staging, tumour delineation and real-time guidance for RT and assessment of treatment response, thereby complementing the limitations of currently used imaging strategies.

KEY POINTS

• MRI's role in oesophageal cancer has been somewhat limited to date. • However MRI's ability to depict oesophageal cancer is continuously improving. • Optimising TN-staging, radiotherapy planning and response assessment ultimately improves individualised cancer care. • MRI potentially complements the limitations of other imaging strategies regarding these points.

Confirmation of histology of PET positive lymph nodes recovered by hand-video-assisted thoracoscopy surgery

PET/CT (Positron Emission Tomography-Computed Tomography) is an advanced diagnostic imaging device that combines both PET and an X-ray CT. This study evaluates the effects of PET/CT on detecting primary tumors and metastases, and looks at the therapeutic effect of minimally invasive surgery on esophageal cancer patients. Eighty patients with esophageal cancer were enrolled in the study between January, 2004 and December, 2007, who were randomly divided into two groups of 40, one of which was treated with hand-video-assisted thoracoscopy surgery (HVATS) esophagectomy and one of which was treated with conventional surgery. All patients underwent a PET/CT scan 2-3 weeks before their operation, and their cervical, thoracic and upper abdominal lymph nodes were biopsied. All the primary esophageal lesions showed high FDG uptake. The maximum standardized uptake value (SUV) was 3.78-25.64 (11.73±5.32), while the mean SUV was 3.65=16.92 (9.12±4.37). Using 2.5 as the SUV standard, all esophageal lesions were detected by PET/CT image. Of the 80 patients, 53 had lymph nodal metastases, with a total of 142 metastatic lymph nodes, which showed high FDG uptake. The maximum SUV was 2.77-14.63 (7.98±3.25), and the mean SUV was 2.31-12.84 (5.34±3.19). The visual analysis from the PET/CT scan showed a sensitivity of 86.62%, a specificity of 95.85%, a positive predictive value of 93.89%, a negative predictive value of 90.69% and an accuracy of 91.94%. The PET/CT scan showed a high sensitivity and specificity in detecting primary esophageal cancer and lymph nodal metastases. The mean post-surgery life expectancies for patients undergoing HVATS and conventional surgery are 27.93 months and 28.05 months, respectively. The two groups showed no statistically significant difference. We thus conclude that PET/CT combined with HVATS is a new choice for esophageal carcinoma patients.

Endoscopic ultrasound-guided fine needle aspiration of the celiac ganglion: A diagnostic pitfall

Endoscopic ultrasound guided fine-needle aspiration (EUS-FNA) is now widely used as a primary tool in the evaluation of lymphadenopathy in both the mediastinum and abdomen. A sympathetic ganglion may be mistaken for an enlarged lymph node on endoscopic ultrasound and are rarely sampled as such. A 51-year-old female presented with a history of weight loss, vomiting for several months, and right upper quadrant discomfort. Computed tomography (CT) and magnetic resonance imaging (MRI) scans showed a dilated common bile duct (CBD) with a possible periampullary mass, paraaortic, and pericelial lymph nodes suspicious for metastatic disease. Endosonography revealed a 17 mm oval hypoechoic structure with distinct margins in the para-aortic, celiac axis region suggestive of an enlarged lymph node. An EUS-FNA was done. Cytology revealed ganglion cells with large oval epithelial-like cells with round nuclei and prominent nucleoli consistent with a benign sympathetic ganglion. It is crucial for the cytopathologist to be aware of the fact that the endoscopist might have sampled a celiac ganglion instead of a celiac lymph node and be able to distinguish the cytological features of a benign sympathetic ganglion from a malignant process.

Comparative study between endoscopic ultrasonography and positron emission tomography-computed tomography in staging patients with esophageal squamous cell carcinoma

Treatment strategy of esophageal cancer mainly depends on accurate staging. At present, no single ideal staging modality is superior to another in preoperative tumor-node-metastasis (TNM) staging of patients with esophageal cancer. We aimed to investigate the efficacy of endoscopic ultrasonography (EUS) and positron emission tomography-computed tomography (PET-CT) for staging of esophageal cancer. We retrospectively studied 118 consecutive patients with esophageal squamous cell carcinoma who underwent esophagectomy with or without neoadjuvant chemoradiotherapy (CRT) over a near 3-year period between January 2005 and November 2008 at a tertiary hospital in Taiwan. Patients were separated into two groups: without neoadjuvant CRT (group 1, n= 28) and with CRT (group 2, n= 90). Medical records of demographic data and reports of EUS and PET-CT of patients before surgery were reviewed. A database of clinical staging by EUS and PET-CT was compared with one of pathological staging. The accuracies of T staging by EUS in groups 1 and 2 were 85.2% and 34.9%. The accuracies of N staging by EUS in groups 1 and 2 were 55.6% and 39.8%. The accuracies of T and N staging by means of PET-CT scan were 100% and 54.5% in group 1, and were 69.4% and 86.1% in group 2, respectively. In group 2, 38 of 90 patients (42.2%) achieved pathologic complete remission. Among them, two of 34 (5.9%) and 12 of 17 (70.6%) patients were identified as tumor-free by post-CRT EUS and PET-CT, respectively. EUS is useful for initial staging of esophageal cancer. PET-CT is a more reliable modality for monitoring treatment response and restaging. Furthermore, the accuracy of PET-CT with regard to N staging is higher in patients who have undergone CRT than those who have not.

Radiotherapy of gastroesophageal junction cancer

Adenocarcinomas of the gastroesophageal junction (GEJ) require multimodal treatment approaches to accomplish good local control and overall survival. While early T1/2 N0 tumors are treated with surgery alone, they are only found in a small subset of patients due to the lack of symptoms at this stage. Most of the tumors are detected in locally advanced stage where surgery alone results in disappointing outcome. Chemotherapy and/or chemoirradiation in the neoadjuvant setting are used to improve conditions for oncological surgery. They aim to achieve a downsizing with a pathological complete remission in the optimal case, improve R0 rates, and upfront treat microscopic metastatic tumor cells. The optimal neoadjuvant treatment approach-chemotherapy, chemoirradiation, or a multiphase approach of both-is yet unclear. Chemoirradiation can improve local control after incomplete surgery and is an important option for patients unfit for surgery. In addition, it enables symptom relief in a palliative setting, namely dysphagia, pain, or bleeding. While target volumes are very much standardized, new technologies as image-guided intensity-modulated radiotherapy (IG-IMRT) and particle therapy have the potential to improve the therapeutic window by minimizing toxicity. Challenges of the present and the future will be the combination of radiotherapy with other cytostatic drugs and modern targeted therapies. This should ideally be integrated into a multimodal setting that is able to identify risk groups according to predictive markers and tumor response, altogether leading to a personalized oncological approach.

The role of endoscopic ultrasound in assessing tumor response and staging after neoadjuvant chemotherapy for esophageal cancer

BACKGROUND

Although the role of endoscopic ultrasound (EUS) in the initial staging of esophageal cancer is well established, its role in assessing tumor response and staging esophageal cancers after neoadjuvant chemotherapy (NAC) is controversial, and this study aimed to investigate this role.

METHODS

This study retrospectively analyzed 110 patients with esophageal cancer who underwent EUS by single surgeon before and after NAC. Tumor response was assessed before and after NAC. Patients with more than a 50% reduction in tumor size based on EUS evaluation were classified as having a significant response to chemotherapy, and those with less than a 50% reduction were categorized as having a partial response. Disease stage was established by tumor node metastasis (TNM) classification. Initial staging was performed using EUS and computed tomography (CT) scans of the chest and abdomen. The EUS-determined stage was compared with the postsurgical pathologic stage. χ(2) analysis and Fisher's exact testing were performed.

RESULTS

A response to NAC was shown by 96 patients (87.3%) and no response by 14 patients (12.7%). Of the 96 responding patients, 37 (38.5%) showed a significant response, whereas 43 (61.5%) of 69 patients showed a partial response. The EUS staging correlated well with the pathologic staging for 9 (64.3%) of the 14 nonresponders and for 34 (35.4%) of the 96 responders to NAC (P = 0.04). The EUS accurately predicted both the T and N status for 26 (23.6%) of the 110 patients. Prediction of N status was significantly more accurate than prediction of the T stage for the post-NAC patients. Of the 110 patients, 43 (39.1%) patients had an accurate T-stage prediction, and 64 (58.2%) had an accurate N stage match (P = 0.02). The T stage was overstaged for 60 (54.5%) of the patients and understaged for 7 of the patients (6.4%).The study found overstaging of the T stage to be more common among the patients who responded to chemotherapy. The N stage was overstaged for 25 (22.7%) and understaged for 21 (19.1%) of the 110 patients.

CONCLUSION

The findings showed EUS to be a useful tool for assessing response to chemotherapy and for evaluating the extent of disease, thus facilitating surgical decision making. However, EUS is an unreliable tool for staging esophageal cancer after NAC. Overstaging of the T stage is significantly more common and could be related to the inflammatory effect or fibrosis after NAC.

PET, CT, and MR Imaging for Assessment of Thoracic Malignancy: Structure Meets Function

Imaging of patients with thoracic malignancy usually requires a multimodality approach. Each of these modalities has its own strengths and weaknesses. CT remains central to the staging and restaging of thoracic malignancies, but has recently been complemented with [18F]-2-fluoro-2-deoxy-D-glucose(FDG)-positron emission tomography (PET) imaging to maximize its potential. Furthermore, because FDG-PET/CT is useful at all stages of the workup and treatment of these patients, this modality has taken hold in the clinical realm for evaluation of patients with thoracic malignancy and is rapidly replacing PET-only imaging. MR imaging is also occasionally used in some patients with thoracic malignancies to improve disease staging or lesion characterization. PET/MR imaging may come to be used to evaluate patients with thoracic malignancies as well.

Nanomedicine--challenge and perspectives

The application of nanotechnology concepts to medicine joins two large cross-disciplinary fields with an unprecedented societal and economical potential arising from the natural combination of specific achievements in the respective fields. The common basis evolves from the molecular-scale properties relevant to the two fields. Local probes and molecular imaging techniques allow surface and interface properties to be characterized on a nanometer scale at predefined locations, while chemical approaches offer the opportunity to elaborate and address surfaces, for example, for targeted drug delivery, enhanced biocompatibility, and neuroprosthetic purposes. However, concerns arise in this cross-disciplinary area about toxicological aspects and ethical implications. This Review gives an overview of selected recent developments and applications of nanomedicine.