Is there a range of time for initiation of adjuvant chemotherapy in patients with malignancy?

Is there a range of time for initiation of adjuvant chemotherapy in patients with malignancy? Adjuvant treatment is an important therapeutic modality particularly in the treatment of breast cancer and coloreclal cancer which are also among the most common cancers in adult population. Meta-analysis results of adjuvant trials has shown that adjuvant chemotherapy increases disease free survival and overall survival in these patients [1, 2]. There are three potential benefits of initiating chemotherapy during the early postoperative period; tumor cells releasing into circulation may be eliminated; growth of inherent drug resistant tumor cells may be prevented; tumor cells showing an increase in proliferation following surgical excision may be more sensitive to cycle-specific cytotoxic agents [3-5]. In clinical practice, however, the optimal time to initiate chemotherapy for a primary tumor is still not established. In an animal study, it has been implied that there is no substantial advantage to early postpoperative initiation of adjuvant chemo-therapy for osteosarcoma of large species [6]. This observation was confirmed in another study involving patients with breast cancer showing that there was no difference in disease-free survival at the end of fourth year in patients who were treated with adjuvant chemotherapy with initiation time of adjuvant chemotherapy ranging from less than 10 weeks, 10-13 weeks, 14-17 weeks and greater than or equal to 18 weeks [7]. On the contrary, a recent trial has shown that early initiation of systemic chemotherapy after surgery might improve outcome in premenopausal patients with ER-negative tumors [8]. The issue about the timing of initiation of adjuvant treatment is particularly important for our country as adjuvant chemotherapy may be delayed for up to several months, often due to lack of information given about treatment options. At that time, we were substantially uncertain as to whether we should initiate adjuvant therapy or not for these latecomer patients. Regarding this conflicting item, we have retrospectively analyzed our data on breast cancer patients (n=1167) followed in our tertiary hospital between 1990-2000 by putting the 'time to adjuvant chemotherapy' (TTAC, range 0.7 8 months) and 'time to progression' (TTP, range 2-98+ months) in the model. Our results revealed that TTAC and TTP was inversely related in patients with breast cancer receiving adju-vant chemotherapy within 4.8 months. A similar relation was not present in those who receive adjuvant therapy beyond this period. Multivariate analysis of of the prognostic variables by Cox-regression method revealed that the TTAC was …