Response-independent survival benefit in metastatic colorectal cancer: a comparative analysis of N9741 and AVF2107

PURPOSE

In the phase III study AVF2107g, bevacizumab (BV) demonstrated a survival benefit when added to irinotecan, fluorouracil, and leucovorin (IFL) in first-line metastatic colorectal cancer (mCRC). In a parallel phase III study, Intergroup N9741, oxaliplatin plus fluorouracil and leucovorin (FOLFOX) also demonstrated a survival benefit compared with IFL. As these two superior therapies have differing mechanisms of action, we explored whether the improved survival associated with the superior therapy was dependent on tumor response.

PATIENTS AND METHODS

For these retrospective, exploratory analyses, patients were defined as responders or nonresponders by whether complete or partial response was achieved with first-line therapy.

RESULTS

Compared with IFL alone, BV plus IFL and FOLFOX each demonstrated statistically significant improvements in progression-free survival (PFS) and overall survival (OS) regardless of objective tumor response. BV-treated nonresponders had a hazard ratio (HR) of 0.63 (P = .0001) for PFS and 0.76 (P = .0188) for OS compared with IFL-treated nonresponders. FOLFOX-treated nonresponders had an HR of 0.75 (P = .0029) for PFS and 0.74 (P = .0030) for OS compared with IFL-treated nonresponders.

CONCLUSION

In both AVF2107g and N9741, objective response did not predict the magnitude of PFS or OS benefit from the superior therapy; nonresponders, despite a poorer prognosis than responders, achieved extended PFS and OS from BV plus IFL or FOLFOX compared with IFL. On the basis of these data, tumor response in metastatic colorectal cancer is not a necessary factor for a therapy to provide benefit to an individual patient.

Quality of life versus prolongation of life in patients treated with chemotherapy in advanced colorectal cancer: A review of randomized controlled clinical trials

Oncologists disagree if chemotherapy in advanced cancer can improve quality of life (QoL), to prolong duration of life, or both. The objective of this study was to clarify the main treatment intention of palliative chemotherapy (PCT): the prolongation of life (PoL); or QoL. Randomized controlled clinical trials of PCT in advanced colorectal cancer that included HRQoL assessment were selected from PubMed and reviewed. Authors' conclusions were based on both PoL- and QoL-related outcomes. However, if PoL and QoL outcomes of the experimental arm were opposite, which was the case in 13 out of 28 trials, the authors generally based their conclusion on PoL outcomes. Authors' conclusions focused mainly on PoL-related outcomes, while QoL-related outcomes were of overriding importance in only 1/28 case. QoL can therefore not be considered as the main outcome of PCT. The review shows that in the context of chemotherapy in advanced colorectal cancer, 'palliative' refers to a life-prolonging intention, whereas within palliative care it refers to an improvement in QoL.