Comparison between two widely used laboratory methods in BRAF V600 mutation detection in a large cohort of clinical samples of cutaneous melanoma metastases to the lymph nodes.

AIMS: The study compares detection rates of oncogenic BRAF mutations in a homogenous group of 236 FFPE cutaneous melanoma lymph node metastases, collected in one cancer center. BRAF mutational status was verified by two independent in-house PCR/Sanger sequencing tests, and the Cobas® 4800 BRAF V600 Mutation Test. RESULTS: The best of two sequencing approaches returned results for 230/236 samples. In 140 (60.9%), the mutation in codon 600 of BRAF was found. 91.4% of all mutated cases (128 samples) represented p.V600E. Both Sanger-based tests gave reproducible results although they differed significantly in the percentage of amplifiable samples: 230/236 to 109/143. Cobas generated results in all 236 cases, mutations changing codon V600 were detected in 144 of them (61.0%), including 5 not amplifiable and 5 negative in the standard sequencing. However, 6 cases positive in sequencing turned out to be negative in Cobas. Both tests provided us with the same BRAF V600 mutational status in 219 out of 230 cases with valid results (95.2%). CONCLUSIONS: The total BRAF V600 mutation detection rate didn't differ significantly between the two methodological approaches (60.9% vs. 61.0%). Sequencing was a reproducible method of V600 mutation detection and more powerful to detect mutations other than p.V600E, while Cobas test proved to be less susceptible to the poor DNA quality or investigator's bias. The study underlined an important role of pathologists in quality assurance of molecular diagnostics.

Molecular alterations in clinical stage III cutaneous melanoma: Correlation with clinicopathological features and patient outcome.

The aim of the present study was to evaluate the frequency and type of oncogenic v-raf murine sarcoma viral oncogene homolog B1 (BRAF)/neuroblastoma RAS viral (v-ras) oncogene homolog (NRAS) mutations in cutaneous melanoma with clinically detected nodal metastases (stage IIIB and C) in relation to clinicopathological features and outcome. The clinicopathological data of 250 patients following therapeutic lymphadenectomy (LND) between 1995 and 2010, as well as BRAF/NRAS mutational status in corresponding nodal metastases, were analyzed. The median follow-up time was 53 months. BRAF mutations were detected in 154 (62%) cases (141 p.V600E, nine p.V600K and four others) and mutually exclusive NRAS mutations were detected in 42 (17%) cases. The presence of a BRAF mutation was found to correlate with patients of a younger age. The five-year overall survival (OS) rate was 33 and 43% for LND and primary tumor excision, respectively, and the five-year disease-free survival (DFS) rate for LND was 25%. No correlation was identified between BRAF/NRAS mutational status and RFS or OS (calculated from the date of the LND and primary tumor excision); for BRAF- and NRAS-mutated melanoma, the prognosis was the same for patients with wild-type (WT) melanoma. The important factors which had a negative impact on OS and DFS were as follows: Male gender, >1 metastatic lymph node and extracapsular extension of nodal metastases. The interval between the diagnosis of the initial melanoma to regional nodal metastasis (median, 10 months) was not significantly different between BRAF-mutant and -WT patients. Our largest comprehensive molecular analysis of clinical stage III melanoma revealed that BRAF and NRAS mutational status is not a prognostic marker in stage III melanoma patients with macroscopic nodal involvement, but may have implications for potential adjuvant therapy.

Molecular characterization and patient outcome of melanoma nodal metastases and an unknown primary site.

BACKGROUND: Melanoma of unknown primary site (MUP) is not a completely understood entity with nodal metastases as the most common first clinical manifestation. The aim of this multicentric study was to assess frequency and type of oncogenic BRAF/NRAS/KIT mutations in MUP with clinically detected nodal metastases in relation to clinicopathologic features and outcome. MATERIALS AND METHODS: We analyzed series of 103 MUP patients (period: 1992-2010) after therapeutic lymphadenectomy (LND): 40 axillary, 47 groin, 16 cervical, none treated with BRAF inhibitors. We performed molecular characterization of BRAF/NRAS/KIT mutational status in nodal metastases using direct sequencing of respective coding sequences. Median follow-up time was 53 months. RESULTS: BRAF mutations were detected in 55 cases (53 %) (51 V600E, 93 %; 4 others, 7 %), and mutually exclusive NRAS mutations were found in 14 cases (14 %) (7 p.Q61R, 4 p.Q61K, 2 p.Q61H, 1 p.Q13R). We have not detected any mutations in KIT. The 5-year overall survival (OS) was 34 %; median was 24 months. We have not found significant correlation between mutational status (BRAF/NRAS) and OS; however, for BRAF or NRAS mutated melanomas we observed significantly shorter disease-free survival (DFS) when compared with wild-type melanoma patients (p = .04; 5-year DFS, 18 vs 19 vs 31 %, respectively). The most important factor influencing OS was number of metastatic lymph nodes >1 (p = .03). CONCLUSIONS: Our large study on molecular characterization of MUP with nodal metastases showed that MUPs had molecular features similar to sporadic non-chronic-sun-damaged melanomas. BRAF/NRAS mutational status had negative impact on DFS in this group of patients. These observations might have potential implication for molecular-targeted therapy in MUPs.

Prognosis in patients with sentinel node-positive melanoma is accurately defined by the combined Rotterdam tumor load and Dewar topography criteria.

PURPOSE: Prognosis in patients with sentinel node (SN)-positive melanoma correlates with several characteristics of the metastases in the SN such as size and site. These factors reflect biologic behavior and may separate out patients who may or may not need additional locoregional and/or systemic therapy. PATIENTS AND METHODS: Between 1993 and 2008, 1,080 patients (509 women and 571 men) were diagnosed with tumor burden in the SN in nine European Organisation for Research and Treatment of Cancer (EORTC) melanoma group centers. In total, 1,009 patients (93%) underwent completion lymph node dissection (CLND). Median Breslow thickness was 3.00 mm. The median follow-up time was 37 months. Tumor load and tumor site were reclassified in all nodes by the Rotterdam criteria for size and in 88% by the Dewar criteria for topography. RESULTS: Patients with submicrometastases (< 0.1 mm in diameter) were shown to have an estimated 5-year overall survival rate of 91% and a low nonsentinel node (NSN) positivity rate of 9%. This is comparable to the rate in SN-negative patients. The strongest predictive parameter for NSN positivity and prognostic parameter for survival was the Rotterdam-Dewar Combined (RDC) criteria. Patients with submicrometastases that were present in the subcapsular area only, had an NSN positivity rate of 2% and an estimated 5- and 10-year melanoma-specific survival (MSS) of 95%. CONCLUSION: Patients with metastases < 0.1 mm, especially when present in the subcapsular area only, may be overtreated by a routine CLND and have an MSS that is indistinguishable from that of SN-negative patients. Thus the RDC criteria provide a rational basis for decision making in the absence of conclusions provided by randomized controlled trials.

Cutaneous melanoma with nodal metastases in elderly people.

BACKGROUND: The impact of age on melanoma patient outcomes is uncertain. OBJECTIVE: The aim of the study was to analyze the characteristics and treatment outcomes in cutaneous melanoma patients ≥ 65 years of age with lymph node metastases. METHODS: We analyzed data from 849 consecutive patients with stage III cutaneous melanoma who were treated between 1994 and 2007 at one institution. Of these, 225 (26.5%) were ≥ 65 years of age. The characteristics and disease-specific survival (DSS) from lymph node dissection (LND) date of patients ≥ 65 years of age were compared with those of younger patients. Median follow-up time was 49 months (range: 6-140 months). RESULTS: In the ≥ 65 years group (51.6% men), the median Breslow thickness was 5.0 mm and 70% was ulcerated. The 5-year DSS rate was significantly lower in older patients (34%). Multivariate analysis identified older age as an independent prognostic factor for DSS in the overall group. Independent negative prognostic factors of DSS in the group of older stage III patients were identified as features of nodal metastases (extracapsular invasion, HR = 1.74, P = 0.009; and ≥ 4 involved lymph nodes, HR = 1.5; P = 0.008) and male sex (HR = 1.5; P = 0.039). CONCLUSIONS: This analysis showed that melanoma patients ≥ 65 years of age are characterized by a higher primary tumor stage and worse prognosis in the presence of regional node metastases than younger patients. Additionally, the results indicate that the same radical surgical therapy is necessary for patients ≥ 65 years old as in younger patients.

Melanoma without a detectable primary site with metastases to lymph nodes.

OBJECTIVE: To compare outcomes of patients with clinical nodal melanoma metastases that occurred without a detectable primary tumor (melanoma of unknown primary site; MUP) with those with a known primary site (KPM). METHODS: We included data from 459 consecutive patients treated from 1994 to 2007 with radical therapeutic lymph node dissection (LND; stage IIIB, C) due to clinically palpable and pathologically confirmed lymph node metastases (229 axillary; 230 ilioinguinal). The median follow-up was 49 months. RESULTS: LND was performed in 59 cases (12.9%; 29 men, 30 women) due to MUP nodal metastases, including 33 axillary (14.4%) and 26 ilioinguinal (11.3%). In the MUP group, the 3- and 5-year survival rates were 48% and 41%, respectively. Similar rates were observed in patients with KPM, even with matched-pair analyses. Established prognostic factors (number of metastatic nodes, p=.005; extracapsular extension of metastases, p=.002) influenced survival in the MUP group. Relapses occurred in 31 (53%) and 299 (74.7%) cases in the MUP and KPM groups, respectively. CONCLUSIONS: Survival rates in the MUP and KPM groups were similar, and the same prognostic factors affected both. Thus, all MUP cases should be treated as standard stage III melanomas.

Sentinel node tumor burden according to the Rotterdam criteria is the most important prognostic factor for survival in melanoma patients: a multicenter study in 388 patients with positive sentinel nodes.

SUMMARY BACKGROUND DATA: The more intensive sentinel node (SN) pathologic workup, the higher the SN-positivity rate. This is characterized by an increased detection of cases with minimal tumor burden (SUB-micrometastasis <0.1 mm), which represents different biology. METHODS: The slides of positive SN from 3 major centers within the European Organization of Research and Treatment of Cancer (EORTC) Melanoma Group were reviewed and classified according to the Rotterdam Classification of SN Tumor Burden (<0.1 mm; 0.1-1 mm; >1 mm) maximum diameter of the largest metastasis. The predictive value for additional nodal metastases in the completion lymph node dissection (CLND) and disease outcome as disease-free survival (DFS) and overall survival (OS) was calculated. RESULTS: In 388 SN positive patients, with primary melanoma, median Breslow thickness was 4.00 mm; ulceration was present in 56%. Forty patients (10%) had metastases <0.1 mm. Additional nodal positivity was found in only 1 of 40 patients (3%). At a mean follow-up of 41 months, estimated OS at 5 years was 91% for metastasis <0.1 mm, 61% for 0.1 to 1.0 mm, and 51% for >1.0 mm (P < 0.001). SN tumor burden increased significantly with tumor thickness. When the cut-off value for SUB-micrometastases was taken at <0.2 mm (such as in breast cancer), the survival was 89%, and 10% had additional non-SN nodal positivity. CONCLUSION: This large multicenter dataset establishes that patients with SUB-micrometastases <0.1 mm have the same prognosis as SN negative patients and can be spared a CLND. A <0.2 mm cut-off for SUB-micrometastases does not seem correct for melanoma, as 10% additional nodal positivity is found.

The survival benefit to patients with positive sentinel node melanoma after completion lymph node dissection may be limited to the subgroup with a primary lesion Breslow thickness greater than 1.0 and less than or equal to 4 mm (pT2-pT3).

BACKGROUND: The survival benefit of sentinel node biopsy is still controversial. The aim of our study was to assess the overall survival (OS; calculated both from the date of primary tumor excision and lymph node dissection) data from two large groups of AJCC 2002 stage-III cutaneous melanoma patients-after completion lymph node dissection (CLND after positive sentinel node biopsy) and after therapeutic LND (TLND for clinically/cytologically detected regional lymph node metastases). MATERIALS AND METHODS: We analyzed the outcomes for 544 consecutive patients, who underwent CLND (47.4%; 258 patients) or TLND (52.6%; 286 patients) at one institution between December 1994 and January 2005. There were no significant differences between the two groups in terms of age and gender distribution and in the parameters of the primary tumor. Median follow-up time was 36 months (range 6-110 months). RESULTS: We found no significant differences in OS (from the date of primary tumor excision) between CLND and TLND patients in the groups with primary tumor thicknesses of 1.0 mm or less or greater than 4.0 mm (pT1 and pT4); however, in patients with thicknesses greater than 1.0 mm and 4.0 mm or less (in subgroups pT2 and pT3), we found significantly better OS for CLND than for TLND patients-CLND: median OS not reached, 5-year OS was 57.2% (95%CI: 44.4-70.1%); TLND: median OS 42.1 months, 5-year OS was 37.9% (95%CI: 26.5-49.2%) (P = 0.0006). In the entire CLND and TLND groups, the median OS and 5-year OS rates were 60.5 months and 52.5% (95%CI: 45.6-61.5%) and 38.2 months and 39.5% (95%CI: 32.7-46.5%), respectively. Based on multivariate analysis, we have found that in the CLND group the important factors negatively influencing OS (from the date of lymphadenectomy) are: male gender, features of primary tumor (higher Breslow thickness and presence of ulceration) and features of nodal metastases (extracapsular invasion and number of involved nodes). In the TLND group, however, the negative prognostic factors are: male gender and features of nodal metastases (extracapsular invasion and number of involved nodes) without the impact of primary tumor characteristics. CONCLUSION: The results of the study demonstrate that the survival benefit after positive sentinel node biopsy with subsequent CLND is probably limited only to the subgroup of patients with primary tumor thicknesses not larger than 4 mm and not less than 1 mm when compared with lymph node dissection of palpable nodes. The primary tumor features have no impact on survival after lymphadenectomy performed for clinically involved nodes.

Rectal gastrointestinal stromal tumors associated with a novel germline KIT mutation.

Somatic, activating mutations of KIT or PDGFRA are early oncogenic events in the majority of sporadic gastrointestinal stromal tumors (GISTs). Also a number of families with GISTs have been described in recent years. The familial GIST syndrome is a rare autosomal dominant disorder with high penetrance and diverse manifestations associated mostly with germline KIT mutations. In this report, we show a novel germline mutation in the juxtamembrane domain of KIT, identified in 2 brothers, both presenting with recurrent, high risk/malignant rectal GISTs. The KIT p.Q575_P577delinsH mutation was found in tumor samples as well as in peripheral blood leukocytes from both patients, proving that the mutation was indeed inherited. Besides rectal GISTs, no other features characteristic for the familial GIST syndrome was observed in either brother or any of their first-degree relatives. The patients were treated with imatinib, achieving either long-term partial response or stable disease. This observation confirms that imatinib can be successfully used in familial GISTs, as it is used in the sporadic advanced tumors, and that tumors bearing a KIT p.Q575_P577delinsH mutation are responsive to imatinib treatment.

Different factors are responsible for predicting relapses after primary tumors resection and for imatinib treatment outcomes in gastrointestinal stromal tumors.

BACKGROUND: The development of accurate diagnostic methods in gastrointestinal stromal tumors (GISTs) and the introduction of imatinib (IM) therapy has focused attention on the factors influencing the prognosis of patients with primary lesions as well as of patients with advanced disease treated with imatinib. MATERIAL/METHODS: The clinico-pathological and genetic factors influencing disease-free survival (DFS) in 335 patients with primary CD117-immunopositive tumors (group A; calculated from primary tumor resection) and progression-free survival (PFS) in 232 metastatic/unresectable GIST patients treated with IM (group B; calculated from the start of imatinib therapy) were analyzed. RESULTS: In group A, statistically significant factors negatively influencing DFS(five-year DFS: 38%), both in univariate and multivariate analysis, were: primary tumor size >5 cm, mitotic index >5/50 HPF (high-power fields), male gender, primary tumor R1 resection or tumor rupture, non-gastric primary tumor localization. In group B, five factors negatively affecting PFS (three-year PFS: 54%) were identified, which were statistically significant both in univariate and multivariate analyses: WHO performance status >/=2, tumor genotype indicating other than exon 11 KIT mutation, high baseline pre-IM granulocyte count, mitotic index >10/50 HPF, and age <45 years at diagnosis. CONCLUSIONS: Different sets of independent biological and pathological prognostic factors were identified for the assessment of the natural course of primary GIST and for the prediction of PFS during IM therapy for advanced GIST.

Presence of homozygous KIT exon 11 mutations is strongly associated with malignant clinical behavior in gastrointestinal stromal tumors.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of gastrointestinal tract. GISTs range from benign indolent neoplasms to highly malignant sarcomas. Gain-of-function mutations of tyrosine kinase receptors, KIT or PDGFRA, have been identified in most GISTs. In this study, we report 36 GIST patients whose tumors had homozygous KIT exon 11 mutations detected by direct sequencing of PCR products. Loss of heterozygosity in KIT locus and other chromosome 4 loci were documented in majority of these tumors. However, fluorescence in situ hybridization with KIT locus-specific probe and chromosome 4 centromeric enumeration probe showed no evidence of KIT hemizygosity in a majority of analyzed cases. These findings are consistent with duplication of chromosome 4 with KIT mutant allele. Homozygous KIT exon 11 mutations were found in 33 primary tumors and 7 metastatic lesions. In two cases, shift from heterozygosity to homozygosity was documented during tumor progression being present in metastases, but not in primary tumors. Among primary GISTs, there were 16 gastric, 18 intestinal and 2 from unknown locations. An average primary tumor size was 12 cm and average mitotic activity 32/50 HPFs. Out of 32 tumors 29 (90.6%) with complete clinicopathologic data were diagnosed as sarcomas with more than 50% risk of metastatic disease, and 26 of 29 patients with follow-up had metastases or died of disease. An average survival time among pre-imatinib patients, who died of the disease was 33.4 months. Based on these findings, we conclude that presence of homozygous KIT exon 11 mutations is associated with malignant course of disease and should be considered an adverse prognostic marker in GISTs.

Risk criteria and prognostic factors for predicting recurrences after resection of primary gastrointestinal stromal tumor.

BACKGROUND: The introduction of adjuvant imatinib in gastrointestinal stromal tumors (GISTs) raised debate over the accuracy of National Institutes of Health risk criteria and the significance of other prognostic factors in GIST. METHODS: Tumor aggressiveness and other clinicopathological factors influencing disease-free survival (DFS) were assessed in 335 patients with primary resectable CD117-immunopositive GISTs (median follow-up, 31 months after primary tumor resection) from a prospectively collected tumor registry. RESULTS: Overall median DFS was 37 months, and estimated 5-year DFS was 37.8 %. In univariate analysis, high or intermediate risk group (P < .000001), mitotic index >5/50 high-power field (P < .00001), primary tumor size >5 cm (P < .00001), nongastric primary location (P = .0001), male sex (P = .01), R1 resection/tumor rupture (P = .0003), and epithelioid cell or mixed cell pathological subtype (P = .05) negatively affected DFS. In multivariate analysis, statistically significant factors negatively influencing DFS for model 1 were mitotic index >5/50 high-power field (P = .004), primary tumor size >5 cm (P = .001), male sex (P = .003), R1 resection/tumor rupture (P = .04), and nongastric primary tumor location (P = .02), and for model 2 were high/intermediate risk primary tumor (P < .0001 and P = .008, respectively), male sex (P = .007), resection R1/tumor rupture (P = .01), and nongastric primary tumor location (P = .02). Five-year DFS for high, intermediate, and low/very low risk group was 20%, 54%, and 96%, respectively. CONCLUSIONS: The risk criteria for assessing the natural course of primary GISTs were validated, but additional independent prognostic factors-primary tumor location and sex--were also identified.

Predictive factors for long-term effects of imatinib therapy in patients with inoperable/metastatic CD117(+) gastrointestinal stromal tumors (GISTs).

THE PURPOSE: To analyze the outcomes of treatment and factors predicting effects of imatinib (IM) therapy in inoperable/metastatic gastrointestinal stromal tumors (GIST) CD117(+) patients. MATERIALS AND METHODS: We identified 232 patients in a prospectively collected Clinical GIST Registry with advanced inoperable/metastatic GIST treated with IM 400-800 mg daily (129 males and 103 females and median age 56 years). Median follow-up time was 26 months. RESULTS: The estimated 3-year progression-free survival (PFS; calculated from the date of the start of IM) was 54% and median PFS was 40.5 months. The following factors significantly and negatively influenced PFS in univariate analysis: poor baseline World Health Organization (WHO) performance status > or = 2 (P < 0.00001), tumor genotype indicating other than KIT exon 11 isoform (P = 0.005), baseline high neutrophils count (P < 0.00001), age <45 years at the diagnosis (P = 0.04), mitotic index >10/50 high-power fields (HPF) (P = 0.001), GIST histological type other than spindle-cell (P = 0.03), baseline low albumin level (P = 0.0005), low baseline hemoglobin level (P < 0.00001), and primary overtly malignant tumors (unresectable and/or metastatic lesions at presentation) (P = 0.05). We identified four factors negatively affecting PFS, statistically significant (P < 0.05) in multivariate analysis: baseline poor WHO performance status > or = 2, high baseline neutrophils count (>5 x 10(9)/l), tumor genotype indicating the presence of non-exon 11 KIT mutant and mitotic index >10/50 HPF. CONCLUSIONS: We confirmed that many advanced GIST patients benefit from IM therapy for a prolonged time, although resistance to therapy is observed. We identified four independent biological factors influencing the PFS during long-term IM therapy.