Non-palpable breast lesions localization techniques - A new priority: Results of a Senonetwork survey among breast centers in Italy.

INTRODUCTION: Non palpable breast tumors are increasingly diagnosed because of screening programs, and their localization during surgery is essential to ensure an adequate resection. Little is known regarding which techniques are used in "real world". MATERIALS AND METHODS: A national web-based survey, with a 21-items questionnaire, was conducted among Breast Centers (BCs) in Italy in 2023. RESULTS: Among 153 BCs, 110 (72 %) participated. Wire-guided localization was reported to be the most used technique, regardless of the volume of malignant tumors treated by each Center (N = 36, 33 %). However, newer techniques such as Radioactive occult lesion localization and magnetic seeds, were reported to be employed in 34 (31 %) BCs, and more often among high-volume BCs (>300 cases/year) (N = 32, 29 % vs. N = 13, 12 %; p = 0.02). Logistic problems of localization were reported to cause delays to the scheduled surgery at least once or in multiple occasions in 26 (24 %) and in 4 (3.5 %) BCs, respectively. Although the majority of BCs declared they were satisfied (N = 48, 44 %) or somewhat satisfied (N = 41, 37 %) with the procedure used in their center, responders stated that they would change their technique, or that they were strongly considering this possibility in 24 (22 %) and in 38 (35 %) cases, respectively. The main barrier to introducing a new technique was associated with procedure costs (90 BCs, 82 %). CONCLUSIONS: There are several critical issues regarding localization techniques at a national level. This should be recognized as a priority because of its impact on both patients and clinical practices.

Early stage breast cancer follow-up in real-world clinical practice: the added value of cell free circulating tumor DNA.

PURPOSE: Physical examinations and annual mammography (minimal follow-up) are as effective as laboratory/imaging tests (intensive follow-up) in detecting breast cancer (BC) recurrence. This statement is now challenged by the availability of new diagnostic tools for asymptomatic cases. Herein, we analyzed current practices and circulating tumor DNA (ctDNA) in monitoring high-risk BC patients treated with curative intent in a comprehensive cancer center. PATIENTS AND METHODS: Forty-two consecutive triple negative BC patients undergoing neoadjuvant therapy and surgery were prospectively enrolled. Data from plasma samples and surveillance procedures were analyzed to report the diagnostic pattern of relapsed cases, i.e., by symptoms, follow-up procedures and ctDNA. RESULTS: Besides minimal follow-up, 97% and 79% of patients had at least 1 non-recommended imaging and laboratory tests for surveillance purposes. During a median follow-up of 5.1(IQR, 4.1-5.9) years, 13 events occurred (1 contralateral BC, 1 loco-regional recurrence, 10 metastases, and 1 death). Five recurrent cases were diagnosed by intensive follow-up, 5 by symptoms, and 2 incidentally. ctDNA antedated disseminated disease in all evaluable cases excepted two with bone-only and single liver metastases. The mean time from ctDNA detection to suspicious findings at follow-up imaging was 3.81(SD, 2.68), and to definitive recurrence diagnosis 8(SD, 2.98) months. ctDNA was undetectable in the absence of disease and in two suspected cases not subsequently confirmed. CONCLUSIONS: Some relapses are still symptomatic despite the extensive use of intensive follow-up. ctDNA is a specific test, sensitive enough to detect recurrence before other methods, suitable for clarifying equivocal imaging, and exploitable for salvage therapy in asymptomatic BC survivors.

Mammographic density to predict response to neoadjuvant systemic breast cancer therapy.

BACKGROUND: Mammographic density (MD) is a risk factor for breast cancer (BC) development, and recurrence. However, its predictive value has been less studied. Herein, we challenged MD as a biomarker associated with response in patients treated with neoadjuvant therapy (NAT). METHODS: Data on all NAT treated BC patients prospectively collected in the registry of Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy (2009-2019) were identified. Diagnostic mammograms were used to evaluate and score MD as categorized by the Breast Imaging-Reporting and Data System (BI-RADS), which identifies 4 levels of MD in keeping with relative increase of fibro-glandular over fat tissue. Each case was classified according to the following categories a (MD < 25%), b (26-50%), c (51-75%), and d (> 75%). The association between MD and pathological complete response (pCR), i.e., absence of BC cells in surgical specimens, was analyzed in multivariable setting used logistic regression models with adjustment for clinical and pathological variables. RESULTS: A total of 442 patients were analyzed, 120 of which (27.1%) attained a pCR. BI-RADS categories a, b, c, and d accounted for 10.0%, 37.8%, 37.1% and 15.2% of cases. Corresponding pCR were 20.5%, 26.9%, 30.5%, 23.9%, respectively. At multivariable analysis, when compared to cases classified as BI-RADS a, those with denser breast showed an increased likelihood of pCR with odds ratio (OR) of 1.70, 2.79, and 1.47 for b, c and d categories, respectively (p = 0.0996), independently of age, BMI [OR underweight versus (vs) normal = 3.76], clinical nodal and tumor status (OR T1/Tx vs T4 = 3.87), molecular subtype (HER2-positive vs luminal = 10.74; triple-negative vs luminal = 8.19). In subgroup analyses, the association of MD with pCR was remarkable in triple-negative (ORs of b, c and d versus a: 1.85, 2.49 and 1.55, respectively) and HER2-positive BC cases (ORs 2.70, 3.23, and 1.16). CONCLUSION: Patients with dense breast are more likely to attain a pCR at net of other predictive factors. The potential of MD to assist decisions on BC management and as a stratification factor in neoadjuvant clinical trials should be considered.

Blood-based genomics of triple-negative breast cancer progression in patients treated with neoadjuvant chemotherapy.

BACKGROUND: As neoadjuvant chemotherapy (NAC) is increasingly used in triple-negative breast cancer (TNBC), we investigated the value of circulating tumor DNA (ctDNA) for patient monitoring prior, during, and after NAC, and circulating tumor cells (CTCs) for disease characterization at clinical progression. MATERIALS AND METHODS: Forty-two TNBC patients undergoing NAC were prospectively enrolled. Primary tumor mutations identified by targeted-gene sequencing were validated and tracked in 168 plasma samples longitudinally collected at multiple time-points by droplet digital polymerase chain reaction. At progression, plasma DNA underwent direct targeted-gene assay, and CTCs were collected and analyzed for copy number alterations (CNAs) by low-pass whole genome sequencing. RESULTS: ctDNA detection after NAC was associated with increased risk of relapse, with 2-year event-free survival estimates being 44.4% [95% confidence interval (CI) 21.4%-92.3%] versus 77.4% (95% CI 57.8%-100%). ctDNA prognostic value remained worthy even after adjusting for age, residual disease, systemic inflammatory indices, and Ki-67 [hazard ratio (HR) 1.91; 95% CI 0.51-7.08]. During follow-up, ctDNA was undetectable in non-recurrent cases with the unique exception of one showing a temporary peak over eight samples. Conversely, ctDNA was detected in 8/11 recurrent cases, and predated the clinical diagnosis up to 13 months. Notably, recurrent cases without ctDNA developed locoregional, contralateral, and bone-only disease. At clinical progression, CTCs presented chromosome 10 and 21q CNAs whose network analysis showed connected modules including HER/PI3K/Ras/JAK signaling and immune response. CONCLUSION: ctDNA is not only associated with but is also predictive of prognosis in TNBC patients receiving NAC, and represents an exploitable tool, either alone or with CTCs, for personalized TNBC management.

VMAT partial-breast irradiation: acute toxicity of hypofractionated schedules of 30 Gy in five daily fractions.

PURPOSE: To report acute toxicities in breast cancer (BC) patients (pts) recruited in a prospective trial and treated with accelerated partial-breast irradiation (APBI) using Volumetric Modulated Arc Therapy (VMAT) delivered with a hypofractionated schedule. METHODS: From March 2014 to June 2019, pts with early-stage BC (Stage I), who underwent breast conservative surgery (BCS), were recruited in a prospective study started at the National Cancer Institute of Milan. Pts received APBI with a hypofractionated schedule of 30 Gy in five daily fractions. Radiotherapy treatment (RT) was delivered using VMAT. Acute toxicity was assessed according to RTOG/EORTC criteria at the end of RT. RESULTS: Between March 2014 and June 2019, 151 pts were enrolled in this study. 79 Pts had right-side and 72 had left-side breast cancer. Median age was 69 (range 43-92). All pts presented with pathological stage IA BC, molecular classification was Luminal A in 128/151 (85%) and Luminal B in 23/151 (15%) cases. Acute toxicity, assessed at the end of RT, consisted of G1 erythema in 37/151 (24. 5%) pts and skin toxicities higher than G1, did not occur. Fibrosis G1 and G2 were reported in 41/151 (27. 1%) pts and in 2/151 pts (1. 3%), respectively. Edema G1 occurred in 8/151 (5. 3%) pts and asthenia G1 occurred in 1/151 (0. 6%) pts. CONCLUSIONS: APBI with VMAT proved to be feasible and can be a valid alternative treatment option after BCS in selected early breast cancer pts according to ASTRO guidelines. A longer follow-up is needed to assess late toxicity.

Axillary nodal involvement by primary tumor features in early breast cancer: an analysis of 2600 patients.

BACKGROUND: Primary tumor characteristics, which are readily available to all clinicians, may aid in selecting the optimal adjuvant therapy for patients with breast cancer (BC). Herein, we investigated the relationship between tumor size, hormone receptor and HER2 status, Ki67 and age with axillary lymph node metastases (ALNM) in early-BC patients. METHODS: We analyzed data on consecutive 2600 early-BC cases collected in the registry of Fondazione IRCC Istituto Nazionale dei Tumori, Milano, Italy. Correlation between Ki67 and primary tumor size (T-size) was calculated by Spearman's rank correlation coefficient. Association of ALNM with Ki67 and other tumor characteristics was investigated by logistic regression. Adjusted odds ratios (ORs) with 95% confidence intervals (95% CIs) were estimated in all cases, and separately analyzed according to age, T-size and BC subtype. RESULTS: Large tumor size strongly associated to ALNM, with an adjusted odds ratio (OR) for each 5-mm increase of 1.32 (95% CI 1.24-1.41), except for triple-negative BC (TNBC) cases. In tumors =10 mm, without lymphovascular invasion, representing the strongest predictor of ALNM (OR 6.09, 95% CI 4.93-7.53), Ki67 resulted particularly informative, with a fourfold increased odds of ALNM for values > 30%. CONCLUSIONS: These results raise the question whether axillary node status is redundant in cases with exceptionally good features, i.e., small tumors with low Ki67, or in those candidate to adjuvant systemic treatment/radiotherapy anyway including TNBC, and support the incorporation of primary BC tumor characteristics as stratification factors in ongoing trials aiming at de-escalating axillary surgical procedures.

Neoadjuvant systemic treatment for breast cancer in Italy: The Italian Society of Surgical Oncology (SICO) Breast Oncoteam survey.

The Italian Society of Surgical Oncology (SICO) Breast Oncoteam developed a survey to explore the state of the art of neoadjuvant treatment for breast cancer in Italy, specifically focusing on cases treated during the two-year period 2014-2015. A questionnaire was sent to Italian Breast Units with a minimum of 150 new breast cancer cases treated/year according to the Senonetwork directory and to the SICO Breast Oncoteam Breast Unit network. A total of 23/107 Breast Units submitted the survey, reporting a total amount of 20156 cases of breast carcinoma (17241 invasive, 2915 in situ) treated in the biennium, corresponding approximately to 20% of newly diagnosed breast cancers in Italy. In the United States, medical treatment before surgery for breast cancer is indicated in about 22.7% of newly diagnosed cases according to the National Cancer Database, while a German study reported approximately 20% of cases treated with neoadjuvant therapy. In our survey, a total of 1673/17241 cases (9.7%) were treated with neoadjuvant therapy, ranging from 2.9% to 23.6% according to different centres, showing heterogeneity in neoadjuvant treatment indications, even in multidisciplinary breast units. Better resources should be engaged to achieve a standardised quality indicator for neoadjuvant treatment, and this indicator could be included among the European Society of Breast Cancer Specialists (EUSOMA) quality indicators. In the near future, we plan to develop a second survey to better test improvements in the employment of neoadjuvant therapy after the expiry of the 2016 European Parliament deadline and after the 2017 St. Gallen Conference recommendations.

Sentinel node biopsy after primary chemotherapy in cT2 N0/1 breast cancer patients: Long-term results of a retrospective study.

BACKGROUND: It is controversial whether sentinel node biopsy (SNB) is adequate in breast cancer patients who become cN0 after primary chemotherapy. To address this we retrospectively compared outcomes in T2 cases given primary chemotherapy, comparing those given axillary dissection (AD) with those given SNB but no AD if sentinel nodes were clinically negative post-chemotherapy. METHODS: We examined overall survival (OS), disease-free survival (DFS), and axillary failure in 317 consecutive cT2 cN0/1 patients given primary chemotherapy followed by quadrantectomy/mastectomy, between January 2002 and December 2007. The approach to the axilla changed over time allowing division into three groups: 101 (31.9%) given upfront AD; 139 (43.8%) given SNB + AD; and 77 (24.3%) given SNB only because the SNs were negative. RESULTS: After median follow-ups of 92 (AD), 99 (SNB + AD) and 72 months (SNB-only), OS (p = 0.131) and DFS (p = 0.087) did not differ between the 3 groups, or between SNB-only and the ypN1 and ypN0 subgroups of SNB + AD, or between the cN0 and cN1 subgroups (before chemotherapy) of the SNB-only group. No SNB-only patient had axillary failure. OS (p = 0.004) and DFS (p = 0.002) were better in patients with complete response than those with partial response or stable/progressive disease. CONCLUSIONS: SNB is adequate in T2 patients who are cN0 after primary chemotherapy, irrespective of axillary status before. Better outcomes after complete pathological remission confirm the prognostic importance of response to primary chemotherapy, and suggest that all T2 patients should receive primary chemotherapy.

New biomarkers to predict the evolution of in situ breast cancers.

BACKGROUND: Genomic studies have shown that gene expression profiles are similar in in situ (CIS) and invasive breast cancers, suggesting that several biofunctional modifications of the transformation process occur before or during the development of CIS lesion. METHODS: We investigated 3 biomarkers in 44 patients with CIS: TG2 (transglutaminase 2), HJURP (Holliday junction recognition protein), and HIF-1α (hypoxia inducible factor-1 alpha). RESULTS: TG2 was more highly expressed than the other two markers and significantly more so in stromal than in tumor cells. HIF-1α evaluation showed a higher expression in both tumor and stromal cells in patients with relapsed G3 tumors, indicating a potential role of this marker in CIS evolution. A greater than sevenfold higher risk of relapse (P = 0.050) was observed in patients highly expressing HJURP in stroma and a tenfold higher recurrence risk (P = 0.026) was seen in those with a higher stromal HIF-1α expression. An important increase in risk accuracy (AUC 0.80) was obtained when HIF-1α and HJURP were evaluated together. CONCLUSIONS: Despite the limited number of relapsed patients, we formulated some hypotheses on the factors responsible for malignant evolution and recurrence which are now being tested in a large case series with a longer follow-up.

Breast metastases from a Renal Cell Carcinoma. A case report and review of the literature.

INTRODUCTION: Metastases to the breast from extra-mammary tumors are uncommon and few sporadic cases are reported in the international literature. An accurate differential diagnosis of secondary cancer is mandatory because both prognosis and treatment differ with respect to primary breast tumors. PRESENTATION OF CASE: We present the case of a 70-year-old woman with an isolated metastasis to the breast occuring 9 years after undergoing a nephrectomy for Renal Cell Carcinoma (RCC). Clinical examination revealed a palpable and mobile mass in the right breast with an enlarged ipsilateral axillary lymph node. Mammographic findings showed a dense, well circumscribed solid mass and the breast ultrasonography findings were those of a hypoechoic homogeneous solid nodule with no posterior attenuation but with prominent peripheral vascularity. A tru-cut biopsy was conclusive for a metastatic deposit by RCC. A whole-body CT scan showed no evidence of further recurrences. The patient underwent metastasectomy and exeresis of the papable lymphnode. DISCUSSION: In patients with former surgery for RCC, a diagnosis based on a preoperative biopsy allows to indicate the proper surgical treatment: in facts, as compared to primary breast tumors treatment, the rationale to pursue wide surgical margins is pointless in cases of metastases and, similarly, the biopsy of the sentinel lymphnode is void of sense due to the lack of its physiopathological prerequisite. CONCLUSION: We suggest to consider a micro-histological biopsy of any new breast lesion appearing in a patient with a history of treatment for RCC. Prompt diagnosis is necessary to choose the right treatment.

Multicentric/multifocal breast cancer with a single histotype: is the biological characterization of all individual foci justified?

BACKGROUND: Invasive multiple breast cancers with a single histological feature (MBCSH) are routinely assessed for biological parameters to indicate adjuvant treatments only in the largest invasive carcinomas. However, the heterogeneity of individual foci in multiple carcinomas has not been widely studied. We analyzed whether such biological features are differently expressed in different MBCSH foci. PATIENT AND METHODS: One hundred and thirteen invasive MBCSH were tested over a 5-year period. The expression of estrogen (ER) and progesterone (PgR) receptors, Ki-67 proliferative index, expression of HER2 and tumor grading were prospectively determined in each tumor focus, and mismatches among foci were recorded. RESULTS: Mismatches in ER status were present in 5 (4.4%) cases and PgR in 18 (15.9%) cases. Mismatches in tumor grading were present in 21 cases (18.6%), proliferative index (Ki-67) in 17 (15%) cases and HER2 status in 11 (9.7%) cases. CONCLUSIONS: In our experience, invasive MBCSH showed heterogeneity among foci. In our clinical practice, such assessment led to 14 (12.4%) patients receiving different adjuvant treatments compared with what would have been indicated if we had only taken into account the biologic status of the primary tumor.

Atypical ductal hyperplasia of the breast: the controversial management of a borderline lesion: experience of 47 cases diagnosed at vacuum-assisted biopsy.

The present paper describes our experience of 47 cases of atypical ductal hyperplasia (ADH) diagnosed at vacuum-assisted biopsy. From June 1999 to December 2003, 47 consecutive diagnoses of non-palpable ADH of the breast were made by 11-gauge vacuum-assisted biopsy (Mammotome). Of these, 17 were subjected to surgical excision and 11 underwent a second Mammotome at the site of the previous vacuum-assisted biopsy. Diagnostic underestimation occurred in only two cases, with a surgical diagnosis of ductal carcinoma in situ. In both patients, aged between 46 and 55 years, the radiological images showed microcalcifications of >20 mm, and the lesions were not completely removed by Mammotome. Despite the obvious limitations of the present study, it can be concluded that the probability of underestimating ADH diagnosis by Mammotome appears to be related to the radiological features of the lesion (>20 mm) and to the adequacy of specimens.

RT-PCR determination of maspin and mammaglobin B in peripheral blood of healthy donors and breast cancer patients.

BACKGROUND: The aim of the present study was to evaluate the accuracy of two markers, maspin and mammaglobin B, singly or in combination, to detect breast cancer. To define better the potential and limits of the two markers for diagnostic purposes, blood positivity was analyzed in relation to clinical, pathological and biological tumor characteristics. PATIENTS AND METHODS: The markers were determined in peripheral blood (PB) samples from 27 healthy donors and 140 previously untreated patients using nested reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: Positivity for maspin in blood samples was observed in 24% of patients with an 89% specificity. For mammaglobin B, positivity was observed in 7% of patients and never in healthy donors. The presence of maspin was correlated with cell proliferation of the primary tumor (P = 0.015), whereas mammaglobin B positivity correlated with pathological stage (P = 0.013). The presence of either marker was significantly related to nodal status. CONCLUSIONS: Our results indicate that the two markers in association could represent a potentially useful non-invasive tool to detect breast cancer. The validation of these markers as indicators of high risk of relapse is ongoing in a series of patients with an adequate follow-up.

Risk factors for lymph node metastases and their prognostic significance in early gastric cancer (EGC) for the Italian Research Group for Gastric Cancer (IRGGC).

BACKGROUND: Lymph node metastases are present in only about 15% of patients with early gastric cancer (EGC) and for this reason, the majority of these patients do not require lymphadenectomy. In Japan, EGC patients undergo less invasive treatment (endoscopic mucosal resection, wedge resection, laparoscopy). However, the indications for and results of these types of treatment are still uncertain. METHODS: In a multicentre retrospective study, we analysed the clinicopathological data referring to 584 early gastric cancer patients who underwent D2 gastrectomy. A comparison was made between patients with and without lymph node metastases in relation to numerous pre- and postoperative variables. Long-term survival and risk factors for lymph node metastases were analysed. The primary aim was to compare our results with those of Western and Japanese authors; we also evaluated the possibility of identifying a subset of patients at low risk of lymph node metastases who may be candidates for endoscopic treatment. RESULTS: The incidence of lymph node metastasis was 14.4%. Univariate and multivariate analyses showed that submucosal infiltration, diffuse histotype, tumour size and Kodama Pen A type were all related to the presence of lymph node metastases. Patients with types I, IIa and IIb mucosal tumours did not present lymph node metastases. Postoperative mortality was 2.2%. Five-year survival in relation to lymph node groups was 95% in N0 patients, 77% in N1 patients and 60% in N2 patients (p = 0.0001, Japanese N-stage). The number of positive lymph nodes also had a prognostic value. Patients with three or fewer positive lymph nodes presented a better 5-year prognosis (83%) than those with more than three positive lymph nodes (48%) (p = 0.0001). CONCLUSIONS: Our study confirms that lymph node involvement is an extremely important prognostic factor. For this reason, the therapeutic strategy of our surgical units is as follows: 1) D2 gastrectomy is the standard treatment even in early gastric cancer (EGC); 2) endoscopic mucosal resection (EMR) could be considered first in types I, IIa and IIb tumours that are diagnosed as limited to the mucosal layer.

Lymph node micrometastases in patients with early gastric cancer: experience with 139 patients.

BACKGROUND: Although lymph node metastases in patients with early gastric cancer (EGC) is an important prognostic factor, the prognostic relevance of lymph node micrometastases is still uncertain. METHODS: The authors studied 1488 lymph nodes, which were histologically confirmed as pN0, dissected from 139 patients who were treated for EGC between 1976-1994. Micrometastases were defined as a single or small cluster of neoplastic cells identifiable only by immunohistochemical methods. RESULTS: Lymph node micrometastases was observed in 24 of the 139 patients (17%). No significant correlation was observed between micrometastases and other clinicopathological characteristics. Analysis of overall survival showed no significant difference between the micrometastases positive and negative groups. CONCLUSION: The results of our study show that the presence of lymph node micrometastases in EGC does not have an influence on patient prognosis.

Identification of occult micrometastases in patients with early gastric cancer using anti-cytokeratin monoclonal antibodies.

The presence of occult micrometastases was evaluated in 1488 lymph nodes removed from 139 patients with node-negative early gastric cancer (EGC). Additional multiple levels of the lymph nodes were examined with haematoxylin-eosin staining and keratin immunostaining. Occult nodal micrometastases were detected in 24 patients (17%) in one or more lymph nodes dissected after a gastrectomy. The cases investigated were a small group from a total of 412 EGC patients who underwent surgical treatment in our hospital between 1976 and 1997; the mean follow-up period was 9 years (range 1-22). We found no significant differences between cytokeratin-negative and positive patients regarding the following clinicopathological parameters: age, gender, tumour size and site, macroscopic and microscopic type, depth of invasion and type of infiltration, according to Kodama's classification. The survival rate at 5 years was 88% and 87% for cytokeratin-negative and positive patients, respectively (log-rank = 0.6; ns). Our data suggest that occult micrometastases do not add useful information and immunohistochemical studies to detect them are probably unnecessary.

Docetaxel and gemcitabine activity in NSCLC cell lines and in primary cultures from human lung cancer.

The activity of the following drugs was investigated in two established NSCLC cell lines: docetaxel, gemcitabine, vinorelbine, paclitaxel, doxorubicin (0.01, 0.1, 1 microg ml(-1)), cisplatin, ifosfamide (1, 2, 3 microg ml(-1)) and carboplatin (2, 4, 6 microg ml(-1)). The cytotoxic activity was evaluated by the sulphorhodamine B assay. The two most active drugs, docetaxel and gemcitabine, used singly and in association, were investigated as a function of treatment schedule. The sequence docetaxel-->gemcitabine produced only a weak synergistic interaction in RAL but a strong synergism in CAEP cells. The synergistic interaction increased in both cell lines after a 48-h washout between the drug administrations. Flow cytometric analysis showed that in docetaxel-->gemcitabine sequence, docetaxel produced a block in G2/M phase and, after 48 h, provided gemcitabine with a large fraction of recovered synchronized cells in the G1/S boundary, which is the specific target phase for gemcitabine. Conversely, simultaneous treatment induced an antagonistic effect in both cell lines, and the sequential scheme gemcitabine-->docetaxel produced a weak synergistic effect only in RAL cells. Moreover, the synergistic interaction disappeared when washout periods of 24 or 48 h between two drug administrations were adopted. The synergistic activity of docetaxel-->48-h washout-->gemcitabine was confirmed in 11 of 14 primary cultures, which represents an important means of validating experimental results before translating them into clinical practice.