Efficacy and safety of single agent or combination adjuvant chemotherapy in elderly patients with colon cancer: a Canadian cancer institute experience.

BACKGROUND: The pattern of adjuvant chemotherapy (AC) use, toxicity profile, and survival benefit in elderly patients with colon cancer (CC) is unclear. We sought to (1) determine whether patients ≥ 65 years with stage III CC were offered single-agent or combination AC, (2) evaluate the reason for selecting single-agent versus combination AC, (3) evaluate the toxicity profile of single-agent and combination AC in the elderly, and (4) determine whether a survival benefit exists for elderly patients receiving combination AC. PATIENTS AND METHODS: A retrospective analysis of records of patients ≥ 65 years diagnosed with stage III CC from 2004 to 2010 was performed to identify baseline characteristics, AC protocols, toxicity, dose intensity, and survival. RESULTS: Two hundred sixty-eight patients ≥ 65 years were diagnosed and treated with AC from 2004 to 2010. Of these patients, 178 were treated with single-agent AC and 90 were treated with combination AC. The most common reasons for choosing single-agent AC were patient preference, comorbidities, and lack of drug coverage. For each year over 65 years, the odds of receiving combination over single-agent AC decreased by 22%. There were more dose delays, dose reductions, and early chemotherapy discontinuation in the combination AC group because of hematologic toxicity. The 5-year overall survival (OS) was 73% in patients who received single-agent AC compared with 84% in those who received combination AC. There was no difference in cancer-related deaths between the groups. CONCLUSION: In elderly patients treated with AC for stage III CC, single-agent AC is used more frequently than combination AC, based on age, comorbidities, and patient choice. Toxicity with combination AC in elderly patients is high. No survival benefit was seen with combination AC over single-agent AC.

Development, characterisation, inheritance, and cross-species utility of American lobster (Homarus americanus) microsatellite and mtDNA PCR-RFLP markers.

Effective management of exploited species demands contemporary knowledge of population structure and mating patterns. Genetic markers can prove useful in providing this knowledge. Despite its commercial importance, genetic markers for American lobster (Homarus americanus) are limited. We developed 12 tetra- and 1 trinucleotide microsatellite loci for American lobster that exhibit little stuttering after PCR amplification. Gene diversity of these loci ranged from 0.516 to 0.929. A four-locus multiplex permits rapid genotyping of progeny in parentage experiments with a paternity exclusion probability over the four loci of 97.8%. We examined the loci for conformity to Hardy-Weinberg expectations (HWE) and linkage using individuals from one location and found that four loci deviated from HWE. We also tested inheritance and pairwise linkage using 48 embryos from each of two females. With the exception of two loci that were derived from the same clone and separated by 72 bp, no evidence of linkage was found. We, for the first time, demonstrate the occurrence of multiple paternity in American lobster. We also observed an apparent occurrence of dispermic androgenesis, possibly the first documentation of such an event within a species. Ten of the loci amplified in European lobster (Homarus gammarus), although two were monomorphic and one deviated significantly from HWE. We quantified mitochondrial DNA (mtDNA) sequence variation through the use of PCR amplification of two DNA fragments, followed by digestion with restriction enzymes; eight haplotypes were detected. One of the two fragments amplified in European lobster. Both sets of markers should prove useful for population discrimination purposes, and the microsatellites, in particular the four-locus multiplex, should prove highly amenable to rapidly addressing questions about mating patterns.