The Impact of Newly Diagnosed Early Breast Cancer on Psychological Resilience, Distress Levels, and the Perception of Health.

Confronting a breast cancer diagnosis, along with complex and challenging treatment procedures, is an extremely stressful experience. Psychological resilience is the ability to maintain or restore normal functioning while facing adversity. We aimed to explore the impact of an early breast cancer diagnosis on psychological resilience, distress, and perception of health. A cross-sectional study was conducted, including 50 patients newly diagnosed with early breast cancer and 67 healthy women with screening mammograms graded 1 or 2 using a Breast Imaging Reporting and Data System. The levels of distress, perception of health, and psychological resilience were assessed using the depression, anxiety, and stress scale, the SF 36-Item Health Survey 1.0, and the Connor-Davidson RISC-25 scale. Differences between variables were examined using the t-test and chi-square test for interval and categorial variables. The surveys were conducted within four weeks of a breast cancer diagnosis. Patients with breast cancer reported a deterioration of their health relative to the previous year and significantly higher levels of psychological resilience, while there was no significant difference between the groups in levels of stress, anxiety, or depression. The process of diagnosis with early breast cancer may activate psychological dynamic processes which are involved in the effective adaptation to acute stress, leading to higher resilience levels in breast cancer patients compared to healthy controls.

Real-world Outcomes of Dual HER2 Blockade Therapy in Metastatic HER2-Positive Breast Cancer: from Induction to Maintenance.

BACKGROUND AND OBJECTIVE: Dual human epidermal growth factor receptor 2 (HER2) blockade with trastuzumab and pertuzumab combined with taxane-based chemotherapy (Cht) has been the standard first-line treatment for HER2-positive metastatic breast cancer (mBC) for years, due to the impressive results of the CLEOPATRA study. Real-world (RW) studies have become critical for assessing treatment effectiveness and safety in real-life circumstances. The aim of this study was to analyze the treatment outcomes of first-line therapy for HER2-positive mBC in RW clinical practice, specifically focusing on the use of maintenance endocrine therapy (ET) in hormone receptor positive (HR-positive) patients. METHODS: This retrospective analysis included 106 HER2-positive mBC patients treated with trastuzumab and pertuzumab combined with taxane-based Cht from October 2015 to December 2020 at the University Hospital Centre Zagreb. RESULTS: At a median follow-up of 30 months, median progression-free survival (PFS) was 25 months for the total population (95% confidence interval [CI] 16 - not analyzed). Patients with de novo mBC had longer median PFS than patients with recurrent disease (not reached vs. 18 months; hazard ratio 1.99; 95% CI 0.69-3.64, p<0.022). Age, hormone receptor positivity, visceral involvement, number of Cht cycles and previous adjuvant trastuzumab did not impact PFS. Most HR-positive patients (N=55, 88.7%) received maintenance ET after induction Cht. CONCLUSION: This retrospective study provides additional data on patient characteristics, treatment and outcomes of RW HER2-positive mBC patients treated with pertuzumab and trastuzumab as first-line therapy. In our institution, maintenance ET after induction Cht has become standard clinical practice.

Interleukin 17 in early invasive breast cancer.

Introduction: Interleukin 17 (IL-17) has a key role in inflammatory responses. Increased serum concentrations of IL-17 have been reported in patients with different types of cancer. Some studies suggest antitumor activity of IL-17 while others speak in favor of its association with poorer prognosis. The lack of data on IL-17 behavior in vivo hinders the efforts to clarify the exact role of IL-17 in breast cancer patients and precludes the usage of IL-17 as potential therapeutic target. Methods: The study included 118 patients with early invasive breast cancer. The serum concentration of IL-17A was measured before surgery and during adjuvant treatment and compared with healthy controls. The correlation of serum IL-17A concentration and different clinical and pathological parameters, including IL-17A expression in the corresponding tumor tissue samples, was analyzed. Results: Significantly higher serum concentrations of IL-17A were found in women with early breast cancer before surgery, but also during adjuvant treatment in comparison to healthy controls. No significant correlation to tumor tissue IL-17A expression was observed. There was a significant postoperative decrease of serum IL-17A concentrations even in patients with relatively lower preoperative values. A significant negative correlation was found between serum IL-17A concentrations and the tumor estrogen receptor expression. Conclusion: The results suggest that the immune response in early breast cancer is mediated by IL-17A, particularly in triple-negative breast cancer. IL-17A-mediated inflammatory response subsides postoperatively, but IL-17A concentrations remain elevated compared to the values in healthy controls, even after the removal of the tumor.

The Challenges and Opportunities of the Implementation of Comprehensive Genomic Profiling in Everyday Clinical Practice with Non-Small Cell Lung Cancer: National Results from Croatia.

Non-small cell lung cancer (NSCLC) has become the best example of precision oncology's impact on outcomes in everyday clinical practice, significantly changing the expectations of all stakeholders, including medical professionals, society, and most importantly, patients. Consequently, the implementation of the precision oncology concept in medical systems, in order to achieve optimal and proven curative effects in NSCLC, is imperative. In this study, we investigated the development, challenges, and results associated with the implementation of precision oncology in NSCLC on a national level in Croatia. We conducted a multicenter, retrospective, cross-sectional analysis on the total population of Croatian patients with metastatic lung cancer, on whose tumors specimen comprehensive genomic profiling (CGP) testing was performed during 2020 and 2021. A total of 48 patients were included in the study. CGP revealed clinically relevant genomic alterations (CRGA) in 37 patients (79%), with a median of 2 (IQR 1-3) CRGA per patient. From the panel of recommended tests, KRAS, MET, and EGFR were the most common alterations, detected in 16 (34%), 5 (11%), and 3 (6%) patients, respectively. CGP revealed additional targetable mutations in 29 (60%) patients who would not have been tested (and consequently, whose mutations would not have been detected) according to the existing everyday standard of practice in Croatia. The tumor mutational burden was reported as high (≥10 Muts/Mb) in 19 patients (40%). CGP analysis reported some kind of targeted therapy for 34 patients (72%). CGP revealed other potentially targetable mutations, and it also determined TMB to be high in a significant number of patients. In conclusion, when possible, CGP should be used as an upfront backbone diagnostic and treatment-oriented work-up in patients with NSCLC.

HER2 Low Breast Cancer: A New Subtype or a Trojan for Cytotoxic Drug Delivery?

Despite the great progress made in the understanding of the biological behavior of certain types of invasive breast cancer, there is still no single histological or molecular classification that encompasses such diversity and accurately predicts the clinical course of distinct breast cancer subtypes. The long-lasting classification of breast cancer as HER2-positive vs. HER2-negative has recently come into question with the discovery of new antibody drug conjugates (ADC), which are proven to be remarkably efficient in treating HER2-low breast cancer. The HER2-low paradigm has challenged the traditional understanding of HER2 overexpression and emphasized the need for more robust HER2 testing in order to encompass HER2 intratumoral heterogeneity and spatial distribution more accurately. It is yet to be seen if low HER2 will remain merely a marker of HER2-equipped tumors targetable with ADCs or if distinctive molecular and phenotypic groups within HER2-low tumors will eventually be discerned.

Effects of trastuzumab and trastuzumab emtansine on corrected QT interval and left ventricular ejection fraction in patients with metastatic (HER2+) breast cancer.

BACKGROUND: Trastuzumab and trastuzumab emtansine are specific antibody and antibody-drug conjugates used in the treatment of human epidermal growth factor receptor 2 (HER2) positive metastatic breast cancer. The aim of this study was to test their effect on the QTc interval duration and left ventricular ejection fraction (LVEF) in our patients, two parameters used in evaluation of cardiotoxicity. From May 2015 to October 2017, 26 patients with preserved LVEF were included in the study. All of them were previously treated with standard paclitaxel and cisplatin-based chemotherapy regimens. Electrocardiogram (ECG) was recorded just before each trastuzumab dose application and six months after the last dose. Echocardiography with LVEF measurement was performed several days before the application of the initial dose, and six months after the last cycle. Later, 24 patients with metastatic disease received additional treatment with trastuzumab emtansine after six months and the same ECG and echocardiography protocol was performed again. Due to reduction in LVEF, two patients were discontinued from additional treatment. RESULTS: A statistically significant QTc prolongation was found after each drug dose application, with an increase in mean QTc duration with every successive application, reaching the peak QTc values just before the fifth cycle of treatment. The QTc interval returned to its initial value six months after the last cycle (p < 0.001). These results were similar for both drugs. Mean LVEF before both treatment protocols was significantly higher compared to LVEF value after the treatment. LVEF before trastuzumab emtansine treatment was non-significantly higher than LVEF after trastuzumab treatment. CONCLUSION: Trastuzumab and trastuzumab emtansine cardiotoxicity manifested as a significant and progressive QTc prolongation after successive drug applications, reaching the peak value just before the fifth cycle of both drugs. Both medications also caused statistically significant but asymptomatic LVEF reduction. Complete reversibility of cardiotoxic effects of both drugs was confirmed by QTc interval and LVEF normalisation after the treatment discontinuation.

The role of interleukin­7 serum level as biological marker in breast cancer: a cross­sectional, observational, and analytical study.

BACKGROUND: The important role that the immune system plays in malignant diseases is well known. The action of interleukin-7 (IL-7) as a cytokine has been observed in many cellular processes, both in normal cells of the immune system and in some cancer cells. The aim of this study has been to explore whether there is any elevation of interleukin-7 serum levels in early invasive breast cancer (EIBC) patients in comparison with healthy controls. In addition, the correlation between the IL-7 serum level and the histopathological characteristics of the tumor has been evaluated. METHODS: This cross-sectional, observational, and analytical study included 213 consecutive patients with EIBC (113 from Croatia and 100 from Kosovo) and 62 healthy participants as the control group (30 from Croatia and 32 from Kosovo). Blood samples have been taken from patients confirmed with breast cancer (BC) by biopsy, prior to surgical intervention and other oncological treatments, as well as from healthy participants. A serum IL-7 level has been measured, using the "Sandwich" ELISA Immunoenzyme test. In addition, after the surgical intervention, histopathological specimen examinations and immunohistochemistry have been performed and analyzed. The differences in the distribution of the numerical variables have been analyzed with the Mann-Whitney U test and Kruskal-Wallis ANOVA test. Correlations have been tested with Pearson coefficients. A P-value < 0.05 has been accepted as statistically significant. RESULTS: The serum level of IL-7 in EIBC patients was significantly higher than in control cases (P 0.001). Patients with invasive lobular carcinoma (ILC) seem to have a lower IL-7 serum level compared to other histological subtypes, and the difference has been significant (P = 0.043). There has been no correlation between IL-7 serum level and histopathological characteristics of the tumor, with neither age nor menopausal status of the patients. CONCLUSIONS: Noting the significant increase in the IL-7 serum level in the EIBC patients as compared to the healthy control group, the use of IL-7 as a potential diagnostic indicator for BC, as well as in the follow-up of the patients after treatment, can be assumed. The lack of correlation with tumor size, lymph node metastasis, and all other histopathological characteristics of the tumor questions its use as a prognostic indicator.

Next-Generation Sequencing of Circulating Tumor DNA Can Optimize Second-Line Treatment in RAS Wild-Type Metastatic Colorectal Cancer after Progression on anti-EGFR Therapy: Time to Rethink Our Approach.

BACKGROUND: Management of Ras wild-type colorectal cancer (CRC) patients upon disease progression after the successful use of targeted treatment with anti-EGFR monoclonal antibodies and backbone chemotherapy remains a clinical challenge. SUMMARY: Development of treatment resistance with prevalence of preexisting RAS mutated clones, RAS mutation conversion, truncation of extracellular receptor domains as well as HER2 and MET amplification are molecular events that can be difficult to follow without the use of sophisticated laboratory techniques. The clinical hurdle of re-biopsy and tumor heterogeneity can be overcome by the implementation of next-generation sequencing (NGS) to analyze circulating tumor DNA (ctDNA) and identify druggable mutations or recovery of RAS-wildness. In this opinion paper, we summarize with critical thinking the clinical approach to be followed after the failure of first-line treatment in Ras wild-type CRC tumors with the use of NGS. Rechallenge with anti-EGFR inhibitors, in case of persistent or recovery of RAS-wildness, and targeted approach of specific mutations (BRAF inhibitors), amplifications (anti-Her2 treatment), or fusion proteins (NTRK inhibitors) can by guided by the use of NGS. The use of NGS platforms for serial analysis of ctDNA is an important step to better understand the molecular landscape of metastatic CRC and guide clinical decisions. KEY MESSAGES: NGS should be considered a mainstay in clinical practice for the management of CRC patients and health authorities should consider reimbursing its use in the appropriate clinical settings.

PROGNOSTIC VALUE OF TOPOISOMERASE 2-ALPHA AND B-MYB IN EARLY BREAST CANCER TREATED WITH ADJUVANT CHEMOTHERAPY.

Breast cancer is the most common malignancy in females. Despite its well-established prognostic factors, our prognostic ability at an individual patient level remains limited. In this study, the immunohistochemical expression of B-Myb and DNA topoisomerase 2-alpha (Topo2a) was analyzed in primary tumors to identify patients with a higher risk of disease recurrence after adjuvant chemotherapy for early invasive breast cancer. We analyzed a cohort of 215 early invasive breast cancer patients having undergone surgery from 2002 to 2003 at the Zagreb University Hospital Centre, including 153 patients treated with adjuvant chemotherapy. All of them were followed-up prospectively for at least ten years according to routine institutional practice. Statistically significant correlations were found between B-Myb and Topo2a expression levels and particular well-established prognostic factors. B-Myb expression was lower in estrogen receptor (ER)-positive tumors (p=0.0773), whereas larger tumors and those with positive lymphovascular invasion displayed a statistically significantly higher B-Myb expression (p=0.0409 and p=0.0196). Higher tumor grade indicated higher Topo2a values (p=0.0102 and p=0.0069). The subgroup with the expression of both proteins above the median value had an almost statistically significantly (p=0.0613) inferior prognosis compared to the rest of the cohort. Study results showed the B-Myb and Topo2a expression to have a prognostic value in breast cancer patients after adjuvant chemotherapy, which should be additionally explored in future studies in a larger patient cohort.

A first report of a rare TP53 variant associated with Li-Fraumeni syndrome manifesting as invasive breast cancer and malignant solitary fibrous tumor.

BACKGROUND: Li-Fraumeni is a rare autosomal dominant cancer predisposition syndrome. The basis is a germline mutation of TP53 gene which encodes tumor suppressor protein resulting in early onset of tumors, most often breast cancer, soft tissue sarcomas, brain tumors, adrenocortical carcinomas, and leukemia. CASE REPORT: We present a case of a young woman with a positive family history for cancer diagnosed with malignant solitary fibrous tumor and luminal B-like invasive breast cancer. Breast cancer and sarcomas account for the majority of tumors associated with Li-Fraumeni syndrome, yet solitary fibrous tumor is a rare clinical entity with no established guidelines for treatment. Even though both primary tumors were successfully resected, the sarcoma relapsed in the form of lung metastases. The NGS analysis revealed single nucleotide variant (c.1101-1G>A) in TP53 gene, affecting the acceptor splice site at intron 10. Until now, only one case of this genetic variant has been documented with conflicting interpretations of pathogenicity. CONCLUSIONS: The knowledge of TP53 mutation status is essential since the management of these patients requires different approach to avoid excessive toxicity due to the risk of developing secondary malignancy. Using the clinical criteria to screen for affected individuals facilitates appropriate early genetic counseling of patients and their families. Following the American College of Medical Genetics criteria, we believe that the reported single nucleotide variant (c.1101-1G>A) in TP53 gene should be considered pathogenic.

The First Wave of the COVID-19 Pandemic and Its Impact on the Level of Distress in Patients with Breast Cancer, a Multicentric Study.

BACKGROUND: Information on the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), later termed coronavirus disease (COVID-19), first emerged by the end of 2019. As the pandemic spread, cancer patients were immediately recognized as a high-risk population with regard to COVID-19 infection. Moreover, epidemiological measures, like social distancing and lockdowns, additionally burdened patients with cancer. Even outside pandemic breast cancer patients are prone to psychological distress with prevalence ranging approximately 20-40%. This multicentric study aimed to examine the impact of COVID-19 pandemic on the level of distress among breast cancer patients in Croatia while the first wave of COVID-19 pandemic. SUBJECTS AND METHODS: Fife hundred forty-five breast cancer patients were offered to participate in the study. A total of two hundred and one patient, with disease stages ranging I-IV, completed the questionnaire. The questionnaire consisted of disease and socio-demographic characteristics followed by the Distress Thermometer and a problem list. The cut off value of 4 was used to define the high level of distress within Distress Thermometer. RESULTS: High distress level was reported in 54.2% of patients. The most significant problems reported by the participants of our study affected emotions, causing worry, sadness, depression, fear, and nervousness. Additionally, specific practical problems emerged (e.g., child care, housing, and work/school), most probably partly due to the lockdowns and social distancing. Interestingly enough, none of the socio-demographic or disease characteristics were linked to the level of distress. CONCLUSIONS: During first wave of COVID-19 pandemic more than half of breast cancer patients, undergoing active oncologic treatment, experienced a high level of distress. Therefore, distress driven by the COVID-19 pandemic should be promptly addressed and additional psychological and social support, targeting specific practical and emotional problems, should be provided for those patients. All the more so as global COVID-19 pandemic far exceeded the duration of the first wave.

Breast Cancer Molecular Subtypes and Oxidative DNA Damage.

BACKGROUND: Oxidative stress is thought to play a major role in etiology of many cancers, including breast cancer. 8-hydroxy-2'deoxyguanosine (8-OHdG) is the most abundant marker of oxidative DNA damage. The aim of this study was to assess the extent of oxidative DNA damage in different breast cancer molecular surrogate subtypes to investigate the prognostic relevance and role of oxidative base lesion (8-OHdG) in the etiology of breast cancer. MATERIALS AND METHODS: 8-OHdG expression was immunohistochemicaly studied on tissue microarrays constructed from 152 patients with invasive breast cancer. Expression was correlated with other prognostic factors, as well as different breast cancer molecular surrogate subtypes such as luminal A, luminal B [human epidermal growth factor receptor 2 (HER2) negative], luminal B (HER2 positive), HER2-enriched ad triple-negative tumors. RESULTS: Triple-negative breast carcinomas (TNBCs) were more frequently 8-OHdG negative compared with non-TNBCs (P=0.036). There was no statistically significant difference between 8-OHdG expression and other breast cancer molecular subtypes.In univariate analysis, there was no significant difference between 8-OHdG expression and breast cancer-specific death, although in multivariate analysis 8-OHdG overexpression was associated with better breast cancer-specific survival (BCSS) (odds ratio=0.04, 95% confidence interval, 0.002-0.62). In Cox regression analysis, patients with moderate and strong 8-OHdG expression had 0.9 times smaller breast cancer death hazard ratio than patients with negative 8-OHdG expression. CONCLUSIONS: Oxidative stress may have less impact in the pathogenesis of TNBCs compared with other surrogate breast cancer molecular subtypes. 8-OHdG may be a promising biomarker in the prediction of prognosis for breast cancer patients.

Circulating Her-2/neu extracellular domain in breast cancer patients-correlation with prognosis and clinicopathological parameters including steroid receptor, Her-2/neu receptor coexpression.

HER-2/neu extracellular domain (ECD) can be detected in blood as a soluble circulating protein. The aim of this study was to analyze the relationship between HER-2/neu extracellular domain in the serum and the prognosis in breast cancer patients. We also correlated HER-2/neu ECD with various clinicopathological factors including steroid receptor, HER-2/neu receptor coexpression. The serum from seventy nine patients with invasive breast cancer and twenty individuals without malignancy was analyzed using the enzyme-linked immune adsorbent assay method. The cut-off value was estimated by the ROC curve analysis (15.86 µg/L). HER-2/neu ECD values in the serum of patients with breast cancer were significantly higher than in control subjects. Circulating HER-2/neu ECD was significantly associated with the histological grade of tumors and the status of axillary lymph nodes. Negative correlation was observed between HER-2/neu ECD in the serum and estrogen receptor positivity. When we analyzed HER-2/neu ECD in relation with coexpression of steroid receptor and HER-2/neu receptor in tissue, statistically higher values were found in the subgroup of patients with steroid receptor negative, HER-2/neu negative tumors than in the other subgroups. HER-2/neu ECD was not an independent factor in the univariate and multivariate analysis. However, elevated HER-2/neu ECD levels were found in patients with breast cancer possessing more aggressive phenotype.

Prognostic value of ki-67 in breast carcinoma: tissue microarray method versus whole section analysis- potentials and pitfalls.

In our study we have compared the prognostic value of two distinct methods of immunohistochemical Ki-67 determination, tissue microarray (TMA) and classical whole section analysis. "Cut-off" values were used according to the 2009 St. Gallen Consensus. Tissue specimens were obtained from a consecutive retrospective series of 215 female patients with primary invasive tumours. Two hundred and thirteen patients were included in the study. Data on Ki-67 was collected by both tissue microarray (TMA) and whole section analysis. Follow up data on overall (OS) and disease-free survival (DFS) were collected. Median follow-up was 95 months (range from 7.8 through 107 months). Mutual correlation of two Ki-67 determination methods was non-significant (Person's r = 0.13417; p = 0.0528). There was statistically significant association of whole section Ki-67 expression with histological and nuclear grade, progesterone receptor and HER2/neu status. The expression of Ki-67 protein in TMAs correlated only with histological and nuclear grade, but not with other traditional clinicopathological factors. Statistically significant differences in DFS (p = 0.0156) and OS (p = 0.0028) were confirmed between subgroups with low and high whole section Ki-67 expression. When subgroups with high and intermediate expression were compared, significant difference was found in DFS (p = 0.0272), but not in OS (p = 0.0624). On the other hand, there was no statistically significant difference either in DFS, or in OS, according to the expression of Ki-67 in TMAs (p = 0.6529; p = 0.7883; p = 0.7966 for DFS, and p = 0.8917; p = 0.6448; p = 0.4323 for OS, respectively). In our study, classical whole section was superior to TMA analysis in terms of prognosis and clinicopathological correlation. Our results indicate that the method used may have impact on prognostic significance of Ki-67. Further studies are needed, covering a greater number of patients and including a precisely defined stage and treatment patient cohorts, in order to solve controversies in Ki-67 assessment methodology.

Fatal outcome of posterior "reversible" encephalopathy syndrome in metastatic colorectal carcinoma after irinotecan and fluoropyrimidine chemotherapy regimen.

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiologic entity characterized by headaches, altered mental status, seizures, and visual disturbances. It can occur in many different clinical entities such as severe hypertension and pre-eclampsia, or due to cytotoxic or immunosuppressive therapies. The pathogenesis of PRES is unclear, with dysregulated cerebral auto-regulation and endothelial dysfunction as important mechanisms proposed. Endothelial dysfunction is important especially in cases associated with cytotoxic therapies. Herein, we describe a patient with PRES with fatal outcome, who presented 5 days after the infusion of cycle 1 of irinotecan hydrochloride, leucovorin calcium, and fluorouracil (FOLFIRI) regimen chemotherapy, without prior hypertension and other comorbidity, suggesting a link between PRES and FOLFIRI regimen. To our knowledge, this case report is the first describing PRES after FOLFIRI regimen, although others have described PRES after FOLFIRI with bevacizumab in colonic cancer patients.

Prognostic value of proliferation markers expression in breast cancer.

In this study, immunohistochemical expression of five proliferation markers: Ki-67, aurora-A kinase, survivin, B-Myb and cyclin B1, was analyzed. Consecutive 215 tumor samples from breast cancer patients operated from 2002 to 2003 were analyzed using the TMA ("tissue microarray") method. The median follow-up was 95 months (from 7.8 to 107 months). Statistically significant correlations between expression levels in five proliferation markers, and correlations between some of the proliferation markers and traditional prognostic factors were found. Statistically significant prognostic influence of aurora-A kinase, survivin and B-Myb expression levels on overall and disease-free survival was found, and cyclin B1 expression level on disease-free survival. A multivariate analysis confirmed survivin and B-Myb expression as independent prognostic factors of overall (p = 0.0195; p = 0.0004) and disease-free survival (p = 0.0107 and p = 0.0205) in breast cancer patients.

[Imatinib in gastrointestinal stromal tumor treatment--results from University Hospital Centre Zagreb]. / Imatinib u lijecenju gastrointestinalnih stromalnih tumora--Iskustva KBC-a Zagreb.

Gastrointestinal stromal tumours (GIST) may be defined as intraabdominal mesenchymal tumours that express KIT protein or have an activating mutation in class III receptor tyrosine kinase gene (KIT or PDGFRalpha). Most GISTs respond to imatinib mesylate, which selectively inhibits both KIT and PDGFRalpha, and is now considered standard systemic therapy for advanced GIST. We assessed the antitumour response of patients treated with imatinib mesylate who had advanced and/or metastatic (GIST). In the Department of Medical Oncology fourteen (14) patients with advanced GIST were treated in the period from year 2002 to 2004. Imatinib mesylate was applied at the dose of 400 mg daily. Only two patients required dose enlargement up to 800 mg. All tumours had positive immunohystochemical expression of KIT. Median age of patients was 56 years. 12 male patients and 2 female patient was treated. Considering primary site of tumour we had 6 small intestine, 4 mesenterium and 4 gastric tumours. Mean duration of the treatment was 14 months (5 to 30 months). Six patients had partial remission, six had stable disease and two progression. Complete remission has not been achieved in any patient. Side-effects were mild and no patient required dose reduction or treatment discontinuation. Our results show the effectivness of targeted antitumour therapy with imatinib mesylate in advanced and/or metastatic GIST, and correspond to those in literature.