Background

Adjuvant chemotherapy (AC) after neoadjuvant chemoradiation and surgical resection has been the standard of care for locally advanced rectal cancer. However, there are no evidence-based guidelines regarding the optimal timing of AC for rectal cancer. The objective of this study was to evaluate the effect of AC timing on overall survival for rectal cancer.

Methods

The National Cancer Database (NCDB) from 2004 to 2016 was queried for primary clinical stage II or III rectal cancer patients who had undergone neoadjuvant chemoradiation followed by surgery and AC. Patients were grouped based on AC initiation: early ≤ 4 weeks, intermediate 4-8 weeks, and delayed ≥ 8 weeks. The primary outcome was overall survival.

Results

We identified 8722 patients, of which 905 (10.4%) received early AC, 4621 (53.0%) intermediate AC, and 3196 (36.6%) delayed AC. Pathological lymph-node metastasis (ypN +) was positive in 73% of early AC, 74% intermediate AC, and 63% delayed AC (p < 0.05). The 5-year survival probability was 71.1% (95% CI 68-74%) for early AC, 73.2% (95% CI 72-75%) intermediate AC, and 65.8% (95% CI 64-68%) delayed AC (p < 0.001). Using Cox proportional hazard modeling, patients undergoing delayed AC had an associated decreased survival compared to patients receiving early AC (HR 1.18; 95% CI 1.028-1.353, p = 0.018) or intermediate AC (HR 1.28; 95% CI 1.179-1.395, p < 0.01).

Conclusions

Delay in AC administration may be associated with decreased 5-year survival. Compared to early or intermediate AC, patients in the delayed AC group were observed to have increased risk of death, despite having lower proportions with ypN + disease. Patients with higher socioeconomic and education status were more likely to receive early chemotherapy.

Purpose

Vatalanib (PTK 787/ZK22584) is an oral poly-tyrosine kinase inhibitor with strong affinity for platelet-derived growth factor and vascular endothelial growth factor (VEGF) receptors. We conducted an open-label, phase II multicenter therapeutic trial investigating the efficacy and tolerability of vatalanib in patients with metastatic or advanced pancreatic cancer who failed first-line gemcitabine-based therapy.

Methods

Vatalanib treatment consisted of a twice daily oral dosing using a "ramp-up schedule," beginning with 250 mg bid during week 1,500 mg bid during week 2, and 750 mg bid on week three and thereafter. The primary objective of this study was to evaluate the 6-month survival rate.

Results

Sixty-seven patients were enrolled. The median age was 64, and 66% (N = 43) had only one prior regimen. Common grade 3/4 adverse events included hypertension (20%; N = 13), fatigue (17%; N = 11), abdominal pain (17%; N = 11), and elevated alkaline phosphatase (15%; N = 10). Among the 65 evaluable patients, the 6-month survival rate was 29% (95% CI 18-41%) and the median progression-free survival was 2 months. Fifteen patients survived 6 months or more. Two patients had objective partial responses, and 28% of patients had stable disease. Changes in biomarkers including soluble VEGF and vascular endothelial growth factor receptor did not correlate with response to drug.

Conclusion

Vatalanib was well tolerated as a second-line therapy and resulted in favorable 6-month survival rate in patients with metastatic pancreatic cancer, compared with historic controls.