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 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.

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.

Correlations of molecular alterations in clinical stage III cutaneous melanoma with clinical-pathological features and patients outcome

8548

Background: To evaluate frequency and type of oncogenic BRAF/NRAS mutations in cutaneous melanoma with clinically detected nodal metastases (stage IIIB,C) in relation to clinicopathologic features and outcome. Methods: We analyzed 221 patients after therapeutic lymphadenectomy-LND (1995-2010) not treated with tyrosine kinase inhibitors and performed molecular characterization of nodal metastases in terms of BRAF/NRAS genes (analyzed by sequencing of respective coding sequences). Median follow-up time was 53 months. Results: BRAF mutations were detected in 139 (63%) cases (127–V600E, 8–V600K, 4-others), mutually exclusive NRAS mutations in 35(15.8%) cases (mainly Q61R and Q61K). BRAF mutation presence correlated with patients' younger age(median 52 vs 60 years for BRAF+ vs. BRAF-, p<0.05), metastases in axillary basin (p<0.05) and less involved nodes (median 3 vs. 4; p<0.05). 5-year overall survival (OS) was 35% and 45% (calculated from date of LND and primary tumor excision, respectively); 5-year recurrence-free survival RFS (from LND) – 29%. We have not found correlation between mutational status and RFS or OS (calculated from date of LND and primary tumor excision) – for BRAF mutated-melanomas prognosis was the same as wild-type melanoma patients(p=0.26) with even trend for better OS for non-V600E mutants. Negative prognostic factors (in univariate and multivariate analysis) for OS and RFS were: male gender (p<0.01), metastatic lymph nodes>1 (p<0.001), nodal metastases extracapsular extension (p<0.001). The interval from diagnosis of first-ever melanoma to regional nodal metastasis (median-10 months) was not significantly different between BRAF-mutant and BRAF wild-type patients (p=0.29). Conclusions: BRAF/NRAS mutational status is not prognostic marker in stage III melanoma patients with macroscopic nodal involvement, what may have implication for potential adjuvant therapy. BRAF status had no impact on disease-free interval from diagnosis of primary melanoma to nodal metastases. Our first-ever comprehensive molecular analysis of clinical stage III melanomas revealed that BRAF-mutants show characteristic clinicopathologic features.

Genotype characterization and prognosis of unknown primary melanoma patients with nodal metastases

e19022

Background: Melanoma of unknown primary site (MUP) is unique, not completely understood entity with nodal metastases as the most common clinical manifestation. The aim of this multicentric study was to assess genetic alterations in MUP with clinically detected nodal metastases in terms of clinicopathological features and prognosis. Methods: We analyzed contemporary series of 37 MUP patients (median age 51 years) after therapeutic lymphadenectomy - LND (period: 1996-2010, 20 – axillary, 16 - inguinal, 1 – other basin) not treated with BRAF inhibitors and performed molecular characterization of BRAF/NRAS mutational status in nodal metastases using direct sequencing of respective coding sequences. Median follow-up time was 37 months. Results: BRAF mutations were detected in 23 (63%) cases (21 V600E - 91%, 2 others - 9%), and mutually exclusive NRAS mutations in 3 (8%) cases (Q61K, Q61R, Q13R). Presence of BRAF mutation correlated with younger age of patients (median 47 vs 60 years for BRAF+ vs. BRAF-, p<0.05). 3-year overall survival (OS) was 45%, median – 23 months (from date of lymph node dissection). We have not found any difference in terms of OS between BRAF mutated- and wild-type melanomas (p=0.99). Conclusions: This unique, comprehensive study on molecular characterization of MUP with nodal involvement stage showed that MUPs have similar molecular features as sporadic non-chronic-sun-damaged melanomas. BRAF mutational status has no prognostic value in this group of patients, what may have potential implications for adjuvant therapy.

Validation of the Joensuu risk criteria for primary resectable gastrointestinal stromal tumour - the impact of tumour rupture on patient outcomes

BACKGROUND

Approval of imatinib for adjuvant treatment of gastrointestinal stromal tumours (GIST) raised discussion about accuracy of prognostic factors in GIST and the clinical significance of the available risk stratification criteria.

METHODS

We studied the influence of a new modification of the NIH Consensus Criteria (the Joensuu risk criteria), NCCN-AFIP criteria, and several clinicopathological factors, including tumour rupture, on relapse-free survival (RFS) in a prospectively collected tumour registry series consisting of 640 consecutive patients with primary, resectable, CD117-immunopositive GIST. The median follow-up time after tumour resection was 39 months. None of the patients received adjuvant imatinib.

RESULTS

The median RFS time after surgery was 50 months. In univariable analyses, high Joensuu risk group, tumour mitotic count >5/50 HPF, size >5 cm, non-gastric location, tumour rupture (7% of cases; P = 0.0014) and male gender had adverse influence on RFS. In a multivariable analysis mitotic count >5/50HPF, tumour size >5 cm and non-gastric location were independent adverse prognostic factors. Forty, 151, 86 and 348 patients were assigned according to the Joensuu criteria to very low, low, intermediate and high risk groups and had 5-year RFS of 94%, 94%, 86% and 29%, respectively.

CONCLUSION

The Joensuu criteria, which include 4 prognostic factors (tumour size, site, mitotic count and rupture) and 3 categories for the mitotic count, were found to be a reliable tool for assessing prognosis of operable GIST. The Joensuu criteria identified particularly well high risk patients, who are likely the proper candidates for adjuvant therapy.

Treatment of advanced dermatofibrosarcoma protuberans with imatinib mesylate with or without surgical resection

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a rare soft tissue sarcoma of the skin characterized by the presence of specific COL1A1-PDGFB fusion protein, which appears as a consequence of the t(17;22) (q22;q13) translocation.

OBJECTIVE

The aim of the study was to perform an analysis of patients with advanced DFSP treated with imatinib, with or without surgery, in clinical practice outside trials.

PATIENTS AND METHODS

We analysed the data of 15 patients (6 male, 9 female; median age 56 years) with locally advanced/initially inoperable and/or metastatic DFSP treated with imatinib 400-800 mg daily between 12/2004 and 06/2009. All diagnoses were ascertained cytogenetically (fluorescent in situ hybridization). Median follow-up time was 16 months (range: 4-81).

RESULTS

Metastases were present in six cases (two lungs, two soft tissue, two lymph nodes). Fibrosarcomatous transformation (FS-DFSP) was confirmed in seven patients (47%). A 2-year progression-free survival (PFS) rate was 60%, and a 2-year overall survival (OS) rate was 78% (median time for PFS/OS was not reached). The best overall responses were: 10 partial responses (67%, including 5 FS-DFSP-1 progressed during the follow-up), 2 stable diseases (13%) and 3 progressive diseases (20%). Seven patients (47%) underwent resection of residual disease and remained free of disease.

CONCLUSIONS

We have confirmed the profound anti-tumour effect of imatinib in DFSP harbouring t(17;22) with long-term responses. Imatinib therapy may in some cases lead to tumour resectability of lesser disfiguration.

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.

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.

Spectrum of KIT and PDGFRA mutations in primary gastrointestinal stromal tumors: Polish Clinical GIST Registry experience

e21504

Background: KIT or PDGFRA gene mutations are found in 80–90% of gastrointestinal stromal tumors (GIST). The prognostic value of those mutations for the outcome in primary tumors is controversial. Objective: To assess the spectrum, frequency and prognostic significance of the KIT and PDGFRA gene mutations in Polish group of surgically treated primary GISTs. Methods: DNA isolated from paraffin blocks from 300 patients (pts) with histologically diagnosed primary GISTs included in clinical registry database, were analyzed using denaturing high performance liquid chromatography (DHPLC) and direct sequencing for KIT (exons 9, 11, 13, 17) and PDGFRA (exons 12, 14, 18) mutations. For primary GIST risk assessment the Miettinen stratification was used. Results: KIT/PDGFRA genes mutations were found in 82% tumors: KIT was mutated in 69% and PDGFRA in 13% of tumors. KIT exon 11 and 9 mutations were found in 61.5% and 7.5% respectively. Among KIT exon 11 mutants the most frequent were deletions (32.7%) followed by point mutations (15.3%), duplications (8.4%) and complex rearrangements (5.1%). KIT exon 11 mutations were found at the similar rates in tumors with gastric and non-gastric localization (53.9% vs. 46.1% respectively) while KIT exon 9 duplications were more often observed in non-gastric GISTs (86.4%, p=0.00036) and PDGFRA mutations were more frequently found in tumors originated from the stomach (86.8%; p=0.00017). In high risk tumors KIT exon 11 deletions were more frequently found than point mutations (p=0.017). On the other hand mutations in PDGFRA were more often observed in very low-/low- than high risk GISTs as compared to KIT exon 11 (p=0.0026). There was no statistically significant correlation between disease-free survival and the spectrum or frequency of mutations. Conclusions: Spectrum and frequency of KIT and PDGFRA mutations in Polish GIST population are similar to the previously described groups. No significance of mutations for disease outcome after surgery of primary tumors was found.

[Table: see text]

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.

The outcomes of imatinib therapy of advanced gastrointestinal stromal tumors (GISTs) originating from the small bowel

10052

Background: The aim of the study was to assess the outcomes of imatinib (IM) therapy in subgroup of patients with advanced CD117(+) GIST originating from small intestine. Methods: In the group of 245 consecutive patients with inoperable and/or metastatic GIST CD117(+) treated with imatinib in the dose of 400–800mg daily and enrolled into prospectively collected Clinical GIST Registry between 09/2001 and 10/2006 we identified 123 patients (50.2%) with GIST originating from small bowel. There were 43 primary unresectable/metastatic tumors and 80 recurrent (after primary surgery) tumors. Median follow-up time was 31 months (range: 3–63). Results: The estimated 3-year progression-free survival (PFS; calculated form the date of the start of IM) and overall survival (OS) were 61% and 80%, respectively. The best responses observed during IM therapy according to RECIST criteria were as follows: complete responses (CRs) - 9 cases (7%), partial responses (PRs) - 66 cases (54%), stable disease SD - 29 cases (24%) and progressive disease (PD) - 19 (15%). In 42 analyzed specimens 29 GISTs (69%) had exon 11 KIT mutations, 9 (21%) - exon 9 KIT mutations and 4 (10%) other genetic abnormalities. We identified three factors negatively affecting PFS statistically significant (p<0.05) in multivariate analysis: baseline poor WHO performance status = 2, tumor genotype with other than exon 11 KIT mutant and primary tumor mitotic index >10/50HPF. Two more additional factors had negative impact on PFS in univariate analysis only: baseline high neutrophil count (p=0.04) and low baseline hemoglobin level (p=0.01). Conclusions: In analysis of the subset of patients with advanced GIST originating from the small bowel we confirmed long-term benefit from IM therapy. We identified three independent biological factors influencing the progression-free survival during imatinib therapy in this group of patients.

[Table: see text]

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.

The criteria of aggressiveness and other prognostic factors for predicting relapses of primary tumors and imatinib (IM) treatment outcomes in advanced KIT immunopositive gastrointestinal stromal tumors (GIST): A report of the Polish Clinical GIST Registry (PCGR)

9544

Background: The development of adjuvant treatment trials with imatinib in GIST has raised the debate about the accuracy of NIH risk criteria consensus and about the significance of other prognostic factors. Methods: We analyzed the criteria of aggressiveness and other clinico-pathological and genetic factors influencing disease-free survival (DFS) in patients with primary CD117-positive tumors (group I: 274 patients; median follow-up 29 months; calculated from primary tumor resection) and progression-free survival (PFS) in metastatic/unresectable GIST patients treated with IM (group II: 179 patients; median follow-up 19 months; calculated from the start of imatinib therapy) enrolled into PCGR. Results: In group I statistically significant (p<0.05) factors negatively influencing DFS both in univariate (log-rank test) and multivariate (Cox’s model) analysis were: primary tumor size > 5 cm, mitotic index > 5/50HPF, male gender, primary tumor R1 resection or tumor rupture, non-gastric primary tumor localization and intermediate/high risk group (3-year DFS for high, intermediate and low/very low risk group was: 28%, 75% and 99%, respectively). In group II we identified 5 factors negatively affecting PFS statistically significant both in univariate and multivariate analyses (p<0.05): tumor genotype indicating other than exon 11 KIT mutation, mitotic index > 10/50HPF, age below 45 years at diagnosis, high baseline pre-IM granulocyte count and poor WHO performance status ≥ 2. Conclusions: We validated the value of criteria of risk groups for the assessment of the natural course of primary GIST, but we also identified additional independent prognostic factors. For the prediction of PFS during IM therapy for advanced GIST we detected 5 different, independent biological and pathological factors.

No significant financial relationships to disclose.

Paraneoplastic syndrome in the course of lung adenocarcinoma: morphological picture and immunohistochemical analysis of the inflammatory infiltrates and PECAM-1 expression

We examined sections of brain, spinal cord, spinal roots, and peripheral nerves from a patient with paraneoplastic syndrome in the course of lung adenocarcinoma. Morphological examination showed marked loss of myelin fibers in peripheral nerves, severe brain tissue edema, and paraneoplastic degeneration involving cerebrum and cerebellum with inflammatory components. Inflammatory infiltrates examined immunohistochemically using antibodies against antigens CD 3, CD 4, CD 8, and CD 20 turned out to be composed of cytotoxic T lymphocytes. The expression of platelet-endothelial cell adhesion molecule-1 (PECAM-1) in blood vessels was increased in comparison with control material, which may facilitate transendothelial lymphocyte migration triggering a cascade of biochemical and morphological reactions observed in paraneoplastic syndrome.