After surgery for colorectal cancer, waiting to begin adjuvant chemotherapy can worsen survival rates, a new study reports.
The study, conducted through researchers at Queen’s University in Ontario, assessed the relationship between time and survival rates in discussing chemotherapy and colorectal cancer through observing the findings of 10 previous studies involving over 15,000 patients. The meta-analysis showed that waiting over four weeks to begin adjuvant chemotherapy significantly decreased a patient’s survival rate.
Specifically, researchers found that the four-week increase in time between surgery and chemotherapy correlated with a 14 percent decrease in survival rates of patients. The results remained statistically significant even after adjusting for potential publication bias.
As to the reason why, the authors write, “the effect of [adjuvant chemotherapy] on survival is thought to be eradication of micro-metastatic deposits in a proportion of patients who would otherwise be destined to have cancer recurrence. There is a substantial theoretical rationale to initiate chemotherapy promptly after curative surgery.
The researchers say this study calls into question the typical advisement of a 12-week window between surgery and beginning adjuvant chemotherapy. Yet, the optimal time for beginning treatment is not known, they concede.
The study authors do encourage more thought to be put into early timing when it comes to adjuvant chemotherapy, however. They conclude the report by urging physicians to more carefully consider timing when discussing treatment with patients.
The study will be presented at the American Society of Clinical Oncology 2011 Annual Meeting.
