Characteristics and clinical evolution of patients with acute myeloblastic leukemia in northeast Mexico: an eight-year experience at a university hospital

BACKGROUND/OBJECTIVE

Acute myeloid leukemia (AML) is the most common acute leukemia in adults. We documented the characteristics and results of treatment of patients with AML at a single reference center.

METHODS

Patients diagnosed with AML between June 2003 and July 2011 at a university hospital in northeast Mexico were studied. Overall survival (OS) and event-free survival (EFS) were determined, and risk factors were analyzed with respect to their influence on prognosis.

RESULTS

A total of 132 AML patients were included. Median age was 32 years. Complete remission (CR) was achieved by 55% of patients. CR was achieved by 65.1% of patients <60 years (n = 109), compared to 8.7% of those >60 years (n = 23; p < 0.001). In all, 39% of patients >60 years suffered an early death, compared to 14.7% of those <60 years (p < 0.001). OS for patients with AML was 35%, whereas EFS was 32%. On multivariate analysis, patients >60 years had a lower OS and EFS (p < 0.001). A total of 28% of patients received a transplant, and they had high er OS and EFS. Conclusions: Our patients were considerably younger and had remarkably lower survival rates than reported for other populations; those >60 years had a higher early death rate, and fewer of these patients achieved CR.

Acute myeloid leukemia with inv(16)(p13q22): involvement of cervical lymph nodes and tonsils is common and may be a negative prognostic sign

Acute myeloid leukemia (AML) with inv(16)(p13q22) or the variant t(16;16)(p13;q22), is strongly associated with the FAB subtype M4Eo. A high incidence of CNS involvement was reported in the 1980s, but otherwise little is known about the pattern of extamedullary leukemia (EML) manifestations in this AML type. We have compiled clinical and cytogenetic data on 27 consecutive AML cases with inv(16)/t(16;16) from southern Sweden. In general, these AMLs displayed the clinical features that have previously been described as characteristic for this disease entity: low median age, hyperleukocytosis, M4Eo morphology, and a favorable prognosis. However, CNS leukemia was only seen in relapse in one patient diagnosed in 1980, whereas the most common EML manifestation in our series was lymphadenopathy (5/27, 19%), most often cervical with or without gross tonsillar enlargement. A review of previously published, clinically informative cases corroborates that lymphadenopathy, with preference for the cervical region, is the most common EML at diagnosis in inv(16)-positive AML (58/175, 33%). CNS leukemia, on the other hand, has been reported in only 17% of the cases, mostly in the relapse setting, with a diminishing frequency over time, possibly due to protective effects of high-dose cytarabine. Other reported EML sites include the scalp, ovaries, and the intestine. Cervicotonsillar EML was in our series associated with a shorter duration of first remission, (P < 0.05), and may hence prove to be an important clinical parameter when deciding treatment strategies in AML with inv(16)/t(16;16).

A morphological pattern of 234 cases of leukemias

Morphological pattern of 234 consecutive cases of various types of leukemias is presented. Acute leukemias (62.8%) were commoner than chronic (37.2%). Amongst acute leukemias, myeloid leukemias (AML) were more frequent as compared to lymphoblastic (ALL). AML:ALL ratio was 2.57:1 in adults and 1:3 in children. Amongst AML cases, M4 was the commonest, followed by M2, M1, M3 and M4 and M6 and M7 respectively. In ALL patients, L1 was the commonest, followed by L2 and L3 respectively. Amongst chronic leukemias, myelocytic leukemia (CML) was more common than lymphocytic leukemia (CLL) with a CML:CLL ratio of 3.1:1. In a total of 60 CML cases, two had juvenile CML, four were between 10 and 15 years of age and the remaining 54 were adults. Hairy cell leukemia (2 cases) and lymphoma/leukemia syndrome (5 cases) were uncommon.

Results of conventional-dose cytosine arabinoside and idarubicin in elderly patients with acute myeloid leukemia

Conventional-dose Ara-C (200 mg/m2 d 1-5) combined with idarubicin (12 mg/m2 d 1-3) was employed as remission induction and consolidation therapy in 23 elderly AML patients with a median age of 66 years (range, 60-75) with AML according to the FAB criteria (M1 n = 3, M2 n = 10, M4 n = 6, M5 n = 2, M6 n = 2), eligible for the study. In seven patients earlier MDS had been documented by previous bone marrow aspirates. The CR rate after one induction course was 65% (15/23). Toxicity was acceptable, with four patients dying during the chemotherapy-induced hypoplasia (4/23). Although 80% of the CR patients received two additional cycles of Ara-C and idarubicin as consolidation therapy, only two patients are still in continuous complete remission more than 12 months after achieving CR. The median disease-free survival of the CR patients was 11.5 months and the median survival of the entire group was 10 months. We conclude that conventional dose Ara-C/idarubicin is an effective protocol for inducing complete remission in elderly patients with AML, but that consolidation therapy consisting of two courses of the same regimen does not produce a relevant rate of long-term disease-free survival.

Cytogenetic study of 50 de novo cases of ANLL from Argentina

BACKGROUND AND METHODS

Consistent and specific chromosomal aberrations have been observed in an increasing number of neoplasias. In the present report, we describe the cytogenetic findings from 50 cases of de novo ANLL in Argentina, South America, studied at diagnosis. In addition, their relation with the FAB classification is analyzed. Children with Down's syndrome and secondary ANLL were excluded from this analysis.

RESULTS AND CONCLUSIONS

Out of 50 banded cases studied, 11 (22%) had normal karyotype, while the remaining 39 (78%) presented abnormal metaphases with structural alterations in the majority of them. Chromosomes 7 and 22 were most frequently involved in numerical alterations in children, while chromosomes 6, 8, 14 and 16 were the ones most often involved in adults. Consistent chromosome rearrangements were observed and they were linked to specific cytomorphologic subsets. The translocations t(8;21) and t(15;17) were seen only in M2 and M3, respectively. The inversion of chromosome 16, inv(16), was a typical finding in M4, but was not restricted to this subtype. Translocation t(2;3) was observed in three cases, all M4, each with a variable chromosome pattern. These results are in accordance with cytogenetic findings in Western Europe and the USA.

ras oncogene activation and occupational exposures in acute myeloid leukemia

BACKGROUND

Epidemiologic studies of acute myeloid leukemias (AMLs) show small increases in risk of disease associated with certain occupations and chemical exposures.

PURPOSE

This study was designed to determine whether the presence of mutationally activated ras oncogenes in AML are associated with occupational and chemical exposures.

METHODS

We interviewed 62 patients with newly diagnosed AML (or their next-of-kin), all of whom were enrolled in a national multicenter clinical trial, and 630 healthy control subjects. DNA extracted from patients' pretreatment bone marrow samples was amplified by using the polymerase chain reaction and probed with allele-specific oligonucleotides for activating point mutations at the 12th, 13th, and 61st codons of three protooncogenes: H-ras (also known as HRAS), K-ras (also known as KRAS2), and N-ras (also known as NRAS).

RESULTS

Patients with ras mutation-positive AML had a higher frequency (six of 10 patients) of working 5 or more years in an a priori high-risk occupation than did patients with ras mutation-negative AML (eight of 52; odds ratio [OR] = 6.8; 95% confidence interval [CI] = 1.3-36). Patients with ras mutation-positive AML were more likely than patients with ras mutation-negative AML to have breathed chemical vapor on the job (OR = 9.1; 95% CI = 1.3-64) or to have had skin contact with chemicals (OR = 6.9; 95% CI = 1.3-37). When ras-positive patients were compared with healthy control subjects, the ORs for occupation and occupational exposures remained elevated, while patients with ras mutation-negative AML showed no increased risk when compared with control subjects.

CONCLUSION

Activation of ras proto-oncogenes may identify an etiologic subgroup of AML caused by occupation and chemical exposure.

IMPLICATION

Disease etiology may be better understood if epidemiologic measures of exposure are integrated with molecular assays of the genetic defects responsible for cancer initiation and promotion.