Abstract 4177: Genetic testing for hereditary colorectal cancer syndromes in Algerian patients: A multicenter study

Background To date, 5% to 6 % of all colorectal cancers (CRCs) are associated with germline pathogenic variants in cancer predisposition genes that confer inherited predisposition to CRC. The use of genetic testing to identify individuals at risk for hereditary CRC syndromes can help to prevent the development of cancer and in the clinical management of the colorectal patients in the areas of both prevention and treatment. We report here the experience of our research laboratory of genetic testing for hereditary polyposis syndromes and Lynch syndrome (LS), respectively, in 126 patients.

Methods Fifty four (54) severe familial adenomatous polyposis (FAP) patients and 72-suspected Lynch syndrome (LS) patients, respectively, were selected from 2851 consecutive colorectal patients at five public hospitals during 2012-2019. Family histories of cancer were obtained from interviews, pedigrees and medical records of patients. Index cases and relatives diagnosed with FAP syndrome or Lynch syndrome have been tested for germline variants in APC, MLH1, MSH2, MSH6 and PMS2 genes, respectively, using PCR-Sanger Sequencing or by NGS using a cancer panel of 30 hereditary cancer genes (Color Genomics).

Results We detected 13 germline pathogenic variants in APC gene in 17 unrelated families, one germline pathogenic variant in BMPRA1 gene in juvenile polyposis syndrome (JPS) patient; seven (7) germline pathogenic variants and 2 variants of uncertain clinical significance (VUS) in MMR genes. Interestingly, 4 novel germline pathogenic variants in APC gene and 3 novel germline pathogenic variants in MMR genes, respectively, have been detected in our study. The most occurring germline pathogenic variants in APC gene were c.3927_3931del and c.4728dup that were identified in four and two index cases in 6 unrelated FAP families, respectively. In Lynch syndrome patients, the rare germline pathogenic variant MLH1 c.1546C>T has been found in 21 individuals from 9 LS families, 6 of them related, with two large kindreds. In addition, the recurrent germline pathogenic variant MSH2 c.942+3A>T has been detected in five unrelated index cases with a strong family history of LS syndrome. Moreover, the rare germline VUS PMS2 c.989-107_989-106insA has been detected in 14 unrelated LS patients and could be reclassified as likely benign. Interestingly, our NGS analysis detected the novel BMPR1A pathogenic variant c.1474-1G>C in young JPS patient that has been misdiagnosed as FAP. The in-silico analysis for this novel variant showed an alteration of the wild type acceptor site and an activation of a cryptic acceptor site, respectively, most probably affecting splicing.

Conclusions Our current study will contribute to the molecular genetics characterization of hereditary colorectal cancer syndromes in Algerian population that is relevant for clinical management in the areas of genetic testing, early diagnosis, treatment and prevention.

Citation Format: Farid Cherbal, Asma-Lamia Boumehdi, Feriel Khider, Karima Landelouci, Abdelwahab Zemam, Sarah Sabri, Adam.Walid Damache, Mohammed Oukkal, Hassen Mahfouf, Ferhat Zebboudj, Mustapha Maaoui. Genetic testing for hereditary colorectal cancer syndromes in Algerian patients: A multicenter study. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4177.

Middle East and North Africa Registry to Characterize Rate of RAS Testing Status in Newly Diagnosed Patients with Metastatic Colorectal Cancer

BACKGROUND

Rat sarcoma virus mutational status guides first-line treatment in metastatic colorectal cancer. This study was a multi center, multi-country ambispective, observational study in the Middle East and North Africa assessing regional rat sarcoma virus testing practices in newly diagnosed patients.

METHODS

The retrospective arm (2011-2014) included adults with metastatic colorectal cancer who had initiated first-line therapy with ≥1 post-baseline visit and survival data. The prospective arm (2014-2019) enrolled newly diagnosed patients with histologically proven metastatic colorectal cancer with ≥1 measurable lesion per Response Evaluation Criteria in Solid Tumors, and tissue availability for biomarker analysis. Data look-back and follow-up were 2 years; the rate of RAS mutation was evaluated.

RESULTS

RAS testing was ordered for patients in retrospective (326/417) and prospective (407/500) studies. In the former, testing was typically prescribed after first-line treatment initiation, significantly more in patients with stage IV disease (P < .005), resulting in the addition of targeted therapy (41.8% anti-epidermal growth factor receptor, 30.2% anti-vascular endothelial growth factor) in wild-type metastatic colorectal cancer, and significantly impacted the treatment of left-sided tumors (P = .037). In the latter, 58.4% were RAS wild-type; 41.6% were RAS mutant. Non-prescription of RAS testing was attributed to test unavailability, financial, or medical rea sons; predictors of testing prescription were older age, primary tumor in ascending colon, and high tumor grade. RAS status knowledge resulted in the addition of anti-vascular endothelial growth factor (20.4%) or anti-epidermal growth factor receptor therapy (21.2%).

CONCLUSION

Before 2014, RAS testing in patients with colorectal cancer in the Middle East and North Africa was often performed after first-line treatment. Testing is more routine in newly diagnosed patients, potentially shifting early treatment patterns.

Neoadjuvant endocrine therapy with or without palbociclib in low-risk patients: a phase III randomized double-blind SAFIA trial

BACKGROUND

The most prevalent subtype of breast cancer (BC) is luminal hormonal-positive breast cancer. The neoadjuvant chemotherapy regimens have side effects, emphasizing the need to identify new startegies.

OBJECTIVE

Analyze the complete pathologic response (pCR) rate and overall response in a low-risk hormone-positive subset of patients receiving neoadjuvant hormone treatment (NAHT) with or without Palbociclib (a CDK4/CDK6 inhibitor) to boost NAHT effectiveness.

MATERIALS AND METHODS

Based on the upfront 21-gene Oncotype DX or low-risk Breast Recurrence Score assay (RS™), the SAFIA trial is designed as a prospective multicenter international, double-blind neoadjuvant phase-III trial that selects operable with luminal BC patients that are HER2-negative for the induction hormonal therapy with Fulvestrant 500 mg ± Goserelin (F/G) followed by randomization of responding patients to palbociclib versus placebo. The pCR rate served as the study's main outcome, while the secondary endpoint was a clinical benefit.

RESULTS

Of the 354 patients enrolled, 253 initially responded and were randomized to either F/G fulvestrant with palbociclib or placebo. Two hundred twenty-nine were eligible for the evaluation of the pathologic response. No statistically significant changes were observed in the pCR rates for the patients treated with the F/G therapy with placebo or palbociclib (7% versus 2%, respectively) per the Chevallier classification (Class1 + Class2) (p = 0.1464) and 3% versus 10% assessed per Sataloff Classification (TA, NA/NB) (p = 0.3108). Palbociclib did not increase the rate of complete pathological response.

CONCLUSION

Neoadjuvant hormonal therapy is feasible in a selected population with a low RS score of < 31 CLINICAL TRIAL: NCT03447132.

Germline variants screening of MLH1, MSH2, MSH6 and PMS2 genes in 64 Algerian Lynch syndrome families: The first nationwide study

Colorectal cancer is the second leading cause of cancer-related deaths in women and men in Algeria. Lynch syndrome (LS) is an autosomal dominant disease caused by heterozygous germline pathogenic variants in mismatch repair genes (MMR) and frequently predisposes to colorectal cancer. However, data about MMR germline pathogenic variants in Algerian patients are limited. This first nationwide study aims to describe clinicopathologic features and germline variants in MMR genes in Algerian families with suspected LS. Sixty-four (64) families with suspected LS were studied. Index cases with LS who fulfilled Amsterdam criteria were screened by PCR-direct sequencing for germline variants in MMR genes: MLH1 (exons 1, 9, 10, 13, 16), MSH2 (exons 5, 6, 7, 12), MSH6 (exons 4 and 8) and PMS2 (exons 6 and 10). We selected these specific risk exons genes since they have a higher probability of harboring pathogenic variants. In addition, two unrelated LS patients were screened by next-generation sequencing using a cancer panel of 30 hereditary cancer genes. Six germline pathogenic variants and one germline likely pathogenic variant were identified in 19 (29.68%) families (4 MLH1, 2 MSH2 and 1 MSH6). Of index cases and relatives who underwent genetic testing (n = 76), 30 (39.47%) had MMR pathogenic gene variants, one (0.13%) had MMR gene likely pathogenic variant and three had MMR variant of uncertain significance, respectively. Two novel germline pathogenic variants in MLH1 (2) and one germline likely pathogenic variant in MSH6 (1) never published in individuals with LS have been detected in the present study. The recurrent MLH1 germline pathogenic variant c.1546C>T has been found in nine LS families, six of them related with two large kindreds, from four North central provinces of Algeria. In addition, the common MSH2 germline pathogenic variant c.942+3A>T has been detected in five unrelated patients with a strong LS family history. The accumulative knowledge about clinicopathological and genetic characteristics of LS in Algerian patients will impact clinical management in the areas of both prevention and treatment.

Final result for SAFIA trial for neoadjuvant palbociclib in patients with operable luminal breast cancer responding to fulvestrant

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Background: Luminal, human epidermal growth factor receptor 2 (HER2)-negative breast cancer (BC) encompasses the most common subtype of breast malignancies. Neoadjuvant strategies of operable BC are primarily based upon chemotherapy (CT), while neoadjuvant hormone therapy (NAHT) has not been well studied in the Middle East and North Africa (MENA) region. However, these tumors might respond poorly to neoadjuvant CT with significant side effects, emphasizing the need to identify patients who could be candidates for NAHT. Methods: The SAFIA trial is a prospective multicentre, international, double-blind, neoadjuvant phase-III trial using upfront 21-gene Oncotype DX Breast Recurrence Score assay (RS) <31) to select operable Luminal HER2-negative patients for induction hormonal therapy with Fulvestrant 500 mg +/– Goserelin (F/G) before randomizing responding patients to F/G + Palbociclib (Cyclin-Dependent Kinase 4/6 inhibitor / CDK 4/6) versus F/G + Placebo. The primary endpoint of this study was the complete pathologic response (pCR) rate. Results: A total of 354 patients were enrolled, leading to 277 patients treated with induction F/G. Of these, 253 responding patients were randomized to F/G fulvestrant with palbociclib or Placebo. Two hundred and thirty patients were evaluable for pathologic response. No statistically significant differences were identified in terms of pCR rates between F/G with palbociclib or placebo: 2% versus 7%, respectively. According to the radiologic responses post- induction F/G, the hormone sensitivity rate was 89.8%, while the clinical benefit of 8–9 months of neoadjuvant F/G was 96%. Safety in the MENA population was acceptable with a grade 3-4 neutropenia rate of 25% in the F/G plus palbociclib arm. The feasibility of performing the 21-gene breast recurrence score assay on core biopsy specimens was optimal in 96.4% of cases. Conclusions: The addition of palbociclib to neoadjuvant F/G did not show any additional benefit in terms of pathologic response, including pCR in neoadjuvant therapy of Luminal HER2-negative BC responding to induction F/G. The use of an upfront 21-gene assay appeared feasible on biopsy specimens, and the identification of tumors with RS<31 allowed to select endocrine sensitive patients, leading ultimately to a 96% clinical benefit with 8–9 months of F/G neoadjuvant therapy. Clinical trial information: NCT03447132. [Table: see text]

Response to Induction Neoadjuvant Hormonal Therapy Using Upfront 21-Gene Breast Recurrence Score Assay-Results From the SAFIA Phase III Trial

Luminal, human epidermal growth factor receptor 2–negative breast cancer represents the most common subtype of breast malignancies. Neoadjuvant strategies of operable breast cancer are mostly based on chemotherapy, whereas it is not completely understood which patients might benefit from neoadjuvant hormone therapy (NAHT).

Epidemiology of breast cancer in women based on diagnosis data from oncologists and senologists in Algeria

BACKGROUND

Breast cancer (BC) is a major health issue threatening women's life. No reliable epidemiological data on BC diagnosed by oncologists/senologists are available in Algeria.

METHODS

The BreCaReAl study, a non-interventional prospective cohort study, included adult women with confirmed BC in Algeria. Disease incidence, patients and disease characteristics, treatment patterns, and mortality rate were recorded up to 12 months of follow-up.

RESULTS

Overall, 1,437 patients were analysed: median age was 48 [41;57] years and 337 (23.5%) women had a family history of BC. BC incidence was 22.3 (95% CI: 21.5; 23.2) cases per 100,000 inhabitants over 8 months. Delayed diagnosis was reported in 400 (29.2%) patients. First line of treatments were mainly chemotherapy and surgery. Twenty-eight serious adverse events were reported including 10 (37.0%) events which led to death. Mortality rate reached 3.2% at 12 months CONCLUSION: A delayed diagnosis highlights the importance of implementing more effective screening strategies.

Incidence of lung cancer in males and females in Algeria: The lung cancer registry in Algeria (LuCaReAl)

BACKGROUND

Lung cancer is a major cause of death worldwide. However, few data on incidence, histologic types and mortality rates of lung cancer were available for Algeria.

METHODS

LuCaReAl is an ongoing descriptive, non-interventional, national, multicenter, prospective and longitudinal study conducted in Algeria, among oncologists and pulmonologists in public community and university hospitals. Median and interquartile ranges are displayed.

RESULTS

Between July 2016 and July 2017, 897 patients were included. Overall incidence of lung cancer was 3.4 [3.2;3.6] cases per 100,000 inhabitants; overall incidence by sex was 5.8 [5.4;6.2] for males and 1.0 [0.8;1.1] for females. Adenocarcinoma was the most common histologic type of cancer. Most tumors were diagnosed at Stage IV.

CONCLUSION

The first results from the LuCaReAl study in Algeria showed that most patients are diagnosed with lung cancer at an advanced stage. The ongoing follow-up will next provide data on the survival and mortality rates.

Prospective evaluation of current RAS mutation testing practices in newly diagnosed metastatic colorectal cancer: Middle East and North Africa Registry (MORE-RAS) Study

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Background: RAS testing is essential for treatment selection in metastatic colorectal cancer (mCRC), as anti-EGFR treatment is indicated only in patients with wild-type (WT) RAS. MORE-RAS was a multicenter, multicountry, observational, ambispective (retrospective + prospective) study designed to evaluate RAS mutation status among patients with mCRC in the Middle East and North Africa (MENA) region. Results of the retrospective study over a prior 2-year period have been previously presented. Here, we report on the prospective evaluation of testing practices in newly diagnosed patients from the same centers. Methods: Five countries (Algeria, Egypt, KSA, Kuwait, Lebanon) enrolled patients between Dec 2014 and Feb 2019. Patients with a new diagnosis of histologically proven mCRC, at least 1 measurable lesion per RECIST criteria, and tissue availability for biomarker analysis were included; those with co-existing malignancies or life expectancy < 6 months were excluded. The primary endpoint was evaluation of the rate of RAS mutation in newly diagnosed patients. Follow-up was for 2 years. Results: 500 patients (mean age 54.6 years; 58% female) were included; 96.4% had Stage 4 disease. Primary tumor sites were sigmoidal colon: 33.4%; rectum: 29.6%; ascending colon: 18.4%; descending colon: 11.4%; transverse colon: 5.2%; and unknown: 1.4%. Most frequent sites of metastasis were liver: 43.4%, lung: 16.0%, and peritoneum: 10.1%. Overall, 407 pts (81.4%; 95% CI, 78%–85%) received prescription for RAS testing. RAS WT was found in 58.4% and mutant in 41.6%; the test was inconclusive in 1 pt. Non-prescription was attributed to test unavailability and medical or financial reasons. The distribution of mutations was KRAS: 85%, NRAS: 4.9%, and not available: 10.1%. Predictors of RAS testing prescription were older age, primary tumor localization in ascending colon, and high tumor grade. Knowledge of RAS status resulted in the addition of bevacizumab or anti-EGFR therapy in 20.4% and 21.2% of pts, respectively at Visit 1 (baseline). Conclusions: RAS testing is now routinely prescribed for newly diagnosed mCRC in the MENA region and can change therapy patterns. The RAS mutation rate in this region differs from that in Western countries.

Prediction of response to neoadjuvant hormonal therapy (NAHT) using upfront oncotype Dx recurrence score (RS): Results from the SAFIA phase III trial

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Background: While hormonal therapy (HT) is a fundamental treatment in breast cancer therapy, neoadjuvant NAHT is not considered standard. The SAFIA trial is a prospective international neoadjuvant Phase III investigating the potential role of the addition of palbociclib (P) in patients (pts) sensitive to HT. We report the results of induction Faslodex (+/- zoladex) in pts initially selected by RS < 31, in order to assess their individual HT sensitivity before double-blind randomization HT vs HT + P followed by surgery. Materials and Methods: A total of 308 pts (stages II and IIIA Luminal A/B HER2 negative) in 24 centers and 6 countries (Middle-East/Maghreb) underwent upfront RS to select pts for induction HT. Pts with RS < 31 received induction neoadjuvant fulvestrant (500 mg i.m Day 1, 14, 28 then q.4 weeks) + goseriline (3.6 mg s.c q.4 w for pre and peri-menopausal pts) for 4 months, followed by clinical and radiological assessment of the disease response before randomization. Response was defined as no progression: Complete Response-CR/ Partial Response-PR: > 50% and Minor Response-MR: < 50% to > 0%/ No Response-NR: progression > 0%. Results: A total of 70 pts (22%) with RS > 31 were excluded, leaving 238 eligible pts for NAHT, age (25-84); pre-peri/ post menopause: 135 (57%)/103 (43%); Luminal A/B: 112 (49%)/114 (51%); Stage II/IIIA: 196 (87%) / 29 (13%). One hundred and seventy-seven pts (177) have validated responses to induction NAHT: CR: 9 pts (5%) / MR: 105 pts (59%) for major response rate: 64% / MR: 56 pts (32%) / NR: 7 pts (4%); available RS 0-10: 23 pts (16%) / RS 11-18: 67 pts (47%) / RS 19-25: 34 pts (24%) / RS 26-30: 18 pts (13%). Correlations between Response to NAHT and RS are shown in the table below (not statistically significant). Conclusions: In our population, upfront Oncotype DX RS < 31 allowed to select pts for induction NAHT without loss of chances with a no-progression rate (CR+PR = MR) of 96%. No significant correlation was found between RS and response to NAHT. Upfront RS > 31 (22%) is selecting pts candidates for neoadjuvant chemotherapy with a potential high risk of endocrine resistance. Clinical trial information: ICRG1201 .

Neoadjuvant chemotherapy with docetaxel, carboplatin and biosimilar trastuzumab in Her2-positive early breast cancer

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Background: Evaluation of the histological response after neoadjuvant chemotherapy with Docetaxel-carboplatin and bio similar Trastuzumab (CANMAB 150mg) in Her2 positive breast cancer. The primary end point was pathologic complete response (pCR) rate, determined from surgical specimens. Methods: Between March 2017 and June 2018, we treated 39 patients with Her2-positive breast cancer satge II (61,5%), III (38,5%), with a neoadjuvant schedule of docetaxel (75 mg/m2), carboplatin (AUC 6) and biosimilar trastuzumab (CANMAB 150mg: 8 mg/kg loading dose then 6 mg/kg) every 3 weeks. Patients were diagnosed at a mean age of 48 years; 52,28% had hormone receptor-positive tumors and 87,17% of patients were node positive. All pts received 6 cycles of chemotherapy followed by surgery and one year of biosimilar trastuzumab. Results: We report the preliminary results of a prospective study on the use of the biosimilar trastuzumab combined with preoperative chemotherapy in Her2 positive breast cancer. Thirty nine patients (100%) completed six cycles of therapy. Surgery was breast conservative in 6 (15,38%) of 39 patients. Fifteen of the Thirty one patients (48%) achieved a pCR, Twelve of the twenty six node-positive patients (46,15%) experienced nodal conversion. There was a significantly lower response in HR-positive patients compared to HR-negative ones (26,7 vs 73,33%). No case of congestive heart failure was observed. Conclusions: The use of biosimilar trastuzumab with docetaxel and carboplatin achieved promising efficacy, with a good pCR rate (48%) in stage II or III Her2-positive breast cancer.

Bevacizumab plus FOLFOX7 as first line treatment in patients with advanced colorectal cancer

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Background: Bevacizumab a monoclonal antibody against vascular endothelial growth factor (VEGF) has shown in combination with chemotherapy a significant survival improvement in pts with advanced colorectal cancer (F. Kabbinavar JCO 2005 and H. Hurwitz NEJM 2004). In this study we investigated the safety and the efficacy of the addition of bevacizumab to FOLFOX7 regimen in pts with metastatic colorectal cancer. Methods: Inclusion criteria: Histological proven colorectal carcinoma, measurable disease at time of inclusion, no prior chemotherapy (adjuvant chemotherapy allowed), no CNS metastasis, no peripheral neuropathy, no other serious concomitant illness, ECOG PS ≤ 2, Urine dipstick of proteinuria <2+, adequate renal and liver function, good bone marrow reserve and informed consent. Pts received bimonthly Oxaliplatin 130 mg/m2 D1, Folinic acid 400 mg/m2 D1, Fluorouracil 2400 mg/m2 46 hours continuous infusion and Bevacizumab 5mg/kg D3 Results: From April 2005 to June 2007, 47 pts (M/F = 28/19, colon/rectum = 28/19) were enrolled in the study. Median age is 52,7 years old (32–74). They received 452 cycles, median=7 range (1–18). All pts were evaluable for toxicity and survival and 46 for responses. Complete response (CR) was achieved in 3 pts (6.6%), partial response (PR) in 28 pts (60.8%), stable disease in 4 pts (8.7%) and progressive disease in 11 pts (24%). The overall response rate (ORR=CR+PR) is 67.3%. Severe toxicity (CTC/NCI ¾ Grade) related to chemotherapy was neuropathy 5.3%, neutropenia 8.4%, anaemia 3.3%, thrombocytopenia 1.8%, vomiting 8.2%, diarrhoea 2.9%, stomatis 4.9% and allergy 0.7%. Toxicity related to Bevacizumab was bleeding CTCNCI grade 1 and 2 in 40.8%, hypertension grade 1 qnd 2 in 3.7% qnd grqde 3 in 0.2. proteinuria grade and 2 in 13.7%. 1 case of phlebitis and 1 case of Bevacizumab allergy Conclusions: Bevacizumab and FOLFOX7 combination is a promising treatment with high efficacy and safety profile for pts with advanced colorectal cancer

No significant financial relationships to disclose.