Palliative Primary Tumor Resection in Patients With Metastatic Colorectal Cancer: For Whom and When?
We thank Lam-Boer et al for their interest in our study1 and are happy to answer their questions.
First, we have clearly mentioned the limitations in our study, such as lack of information on chemotherapeutic drugs, antibodies, performance status, and number and site of metastases. Such information cannot be ascertained in the SEER (Surveillance, Epidemiology, and End Result Program of the National Cancer Institute, United States) data. Hence, it is impossible to identify patients receiving exclusively best supportive care. Conversely, the great strength of the SEER database is to mirror general clinical practice.2 Indeed, the population-based nature of the registry does reflect the real-world outcomes for patients with metastatic colorectal cancer and is associated with a high degree of generalizability. In contrast, randomized controlled trials are often performed with highly selected patients in a somewhat artificial setting.3 Hence, we would like to express a word of caution when making assumptions regarding the use of systemic treatments by comparing survival results from SEER data with those of randomized controlled trials.4
Second, quality of life is not recorded in the SEER data. We strongly disagree with Lam-Boer et al that a “survival benefit of at least six months is necessary to balance out surgery-related impact on quality of life.” This proposed treatment strategy is simplistic and does not reflect the complexity an oncological team has to face before making such a decision. Whether or not the primary tumor should be removed in an otherwise unresectable situation depends on a variety of parameters such as the patient's performance status, symptoms caused by the primary tumor, location of the primary tumor, overall tumor burden, response to systemic treatment, and so forth. Hence, an attempt to define a minimal survival benefit for all patients is fallacious.
Finally, we disagree with Lam-Boer et al that the option of palliative tumor resection should be discussed with all patients, as certain (eg, those progressing during systemic treatment) patients should not undergo palliative surgery except if the primary tumor is symptomatic. It is key to identify a subset of patients who will benefit most from a surgical procedure. In this regard, the ideal randomized study design is to start with systemic treatment in both the standard and experimental arm and perform only primary tumor resection in patients with stable disease or tumor response. Unfortunately, none of the ongoing randomized trials follow this treatment strategy.