In Europe, the benefits of neoadjuvant radiation therapy (both short-course and a protracted course) have been shown in randomized phase III trials, but the role of PKA inhibitor concurrent chemotherapy remains a question of debate. The importance pre-therapy staging is stressed as sequencing of therapy appears to significantly impact outcome. In addition, close follow-up in the post-treatment setting Inhibitors,research,lifescience,medical appears of great importance both in terms of managing treatment-related side-effects and for early recurrence detection.
In this issue of the Journal of Gastrointestinal
Oncology, Katkoori et al report on the impact of the pro-apoptotic protein Bax and its ratio
to the anti-apoptotic portein Bcl2 (Bax/Bcl2) by immunohistochemistry grading on the outcome of patients Inhibitors,research,lifescience,medical with colorectal cancer treated with curative intent surgery or curative intent surgery followed by 5-FU-based chemotherapy (1). The chemotherapy group was selected from a patient population treated with curative intent surgery followed by at least 3 months of infusional 5-FU based chemotherapy or 6 months of bolus 5-FU-based chemotherapy between the years 1987-1993. The surgical control group was matched to the chemotherapy group by age, sex, stage, ethnicity, differentiation, and tumor location. The investigators Inhibitors,research,lifescience,medical demonstrate a better survival outcome Inhibitors,research,lifescience,medical in patients with increased Bax expression vs low Bax expression in the absence of chemotherapy (surgery only). A trend towards a worsened survival outcome is noted in patients with increased Bax expression vs low Bax expression in the presence of chemotherapy. Furthermore, a low Bax/Bcl2 ratio was associated with a better survival outcome in comparison to high Bax/Bcl2 ratio in the presence of 5-FU based chemotherapy. The authors conclude that patients with higher Bax expression may not benefit from adjuvant chemotherapy. One
has to recognize that Inhibitors,research,lifescience,medical there are several limitations to the Katkoori study. First, the study suffers from a small and heterogeneous population. Twenty-five percent also of patients investigated in this study had stage IV disease. Therefore, data extrapolation from this heterogeneous population to adjuvant treatment in stage II-III disease cannot be applied. If the intent of the study is to investigate the impact of Bax on the effectiveness of adjuvant chemotherapy, it would have been advisable to limit the study population to stages II-III disease. Second, it is impossible from the current study design to conduct a meaningful evaluation of the impact of Bax or Bax/Bcl2 or p53 on OS within the surgical and chemotherapy groups.