Palliative Resection of Primary Tumor May Improve Survival in Patients With Metastatic Colorectal Cancer
Palliative resection of the primary tumor was associated with a statistically significant and clinically meaningful improvement in overall survival in patients with metastatic colorectal cancer, according to the results of a study reported in the Annals of Surgical Oncology. Gresham et al noted that these improved outcomes occurred regardless of the receipt of systemic therapy and the extent of metastases.
Surgical resection of the primary tumor represents curative treatment for patients who present with early-stage colorectal cancer. However, its role remains controversial for patients who present with advanced colorectal cancer. Typically, surgical resection is used for palliative purposes in those with symptomatic metastatic colorectal cancer or in patients likely to experience tumor complications such as obstruction, perforation, or bleeding.
Whether palliative resection of the primary tumor in the setting of advanced colorectal cancer offers a survival benefit remains uncertain. Although some studies have suggested an improvement in outcomes with surgery, they have primarily been nonrandomized, retrospective, single-institution experiences. In fact, most of these studies did not take into account the effect of contemporary chemotherapeutic regimens such as FOLFIRI (leucovorin, fluorouracil [5-FU], irinotecan) and FOLFOX (leucovorin, 5-FU, oxaliplatin), nor did they consider the impact of newer biologic or targeted agents.
Study Details
Gresham and colleagues evaluated the association between primary tumor resection and overall survival in a population-based cohort of patients with metastatic colorectal cancer. A total of 517 patients diagnosed with de novo stage IV colorectal adenocarcinoma who received their cancer care from the British Columbia Cancer Agency took part in this clinical trial. Excluded from the study were patients with either a synchronous or colorectal tumor previously treated with adjuvant therapy and those with a histologic diagnosis other than adenocarcinoma.
A closer look at the patient demographics revealed that 282 were men and 235 were women. About half of the patients were < 65 years of age. Nearly 75% of the patients (378) underwent palliative resection of their primary tumor, and approximately 25% (139 patients) did not undergo surgery. The most common surgery performed was segmental resection (60%).
In a comparison of the resected and nonresected groups, resected patients tended to be younger (median age, 66.5 vs 70 years) and had a better Eastern Cooperative Oncology Group (ECOG) performance status (61% vs 38%). In addition, resected patients were more likely to have colonic primary tumors and to receive palliative systemic therapy than were unresected patients. The number and location of metastases did not differ between the groups (P = .29 and P = .26, respectively).
Better Outcomes With Palliative Resection
The investigators found that patients who underwent palliative resection of the primary tumor had better outcomes than did those who did not undergo palliative resection. The median overall survival associated with surgery was 17.9 months, compared with 7.9 months without surgery (hazard ratio [HR] = 0.46, 95% confidence interval [CI] = 0.37–0.56, P < .0001).
A univariate analysis demonstrated better long-term survival rates with surgery as well. The 3-year overall survival rates were 23.3% for resected patients and 7.1% for unresected patients, and the 5-year overall survival rates were 12.5% for resected patients and 2.0% for unresected patients.
Moreover, the investigators conducted a propensity score–matched analysis. They found that the median overall survival was 22.9 months for resected patients, compared with 8.4 months for unresected patients (HR = 0.57, 95% CI = 0.42–0.77; P = .0004). In this analysis, they also found that the prognosis was more favorable in the resected group (P = .0017).
In addition, two characteristics were shown to be independently associated with a more favorable overall survival. They were an ECOG performance status of 0 or 1 (HR = 0.55, 95% CI = 0.38–0.79, P = .001) and a carcinoembryonic antigen value ≤ 4 ng/mL (HR = 0.52, 95% CI = 0.32–0.82, P = .005).
Overall, consistent benefits with palliative resection were seen across all study subgroups. The receipt of palliative systemic therapy and the extent of metastases did not appear to modify the effect of palliative resection of the primary tumor on overall survival (P = .80 and .32, respectively).
Closing Thoughts
The investigators revealed that the positive prognostic effect of palliative resection of the primary tumor in patients with metastatic colorectal cancer seen in their study was consistent with previous studies. “We believe that our propensity score–matched analysis offers a more reliable representation of the effect of primary tumor resection,” they declared. “We accounted for additional prognostic factors (such as the use of systemic therapy and the extent of metastases) in our analyses, whereas prior research did not.”
Gresham and colleagues offered two potential reasons for the positive effect of surgery seen in their study: altered tumor biology as a result of surgical resection due to a reduced overall tumor burden and reduction of complications associated with the primary tumor.
Winson Y. Cheung, MD, MPH, of the British Columbia Cancer Agency, Vancouver, British Columbia, is the corresponding author of the article in the Annals of Surgical Oncology.
This study was supported by the British Columbia Cancer Agency Gastrointestinal Cancers Outcomes Units, the British Columbia Cancer Foundation, and the Canadian Society Research Institute. The study authors reported no potential conflicts of interest.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
