SEMS has been used to treat obstructive colonic cancer since the 1990s . Although the efficacy of SEMS placement for obstructive CRC is still debatable, some previous studies have shown improvements in short- and long-term outcomes [7, 19, 20]. To the best of our knowledge, this is the first report to discuss the short- and long-term outcomes of SEMS as a BTS for obstructive and symptomatic CRC in stage IV, compared to emergent or urgent resection of primary tumor. The results of this study can show the efficacy of SEMS in this setting with less invasive treatment, regarding surgical procedures or stoma creation rate.
Particularly for obstructive stage IV CRC, ESGE guidelines recommend SEMS for palliative aims since it may improve short-term outcomes in comparison with emergency surgery, which is potentially related to higher rates of mortality or morbidity . However, since the treatment strategies for stage IV CRC have advanced in the last decades, a certain proportion of patients in that setting can now survive longer, receiving palliation with a combination of surgery, systemic chemotherapy, or radiotherapy [21, 22]. In this regard, the aim of SEMS placement for obstructive stage IV CRC needs to be discussed further.
Resection of primary tumors in stage IV CRC has been topic of debate. Some previous reports showed some benefits of primary tumor resection, such as reduction of late complications or improvement of overall survival (OS), even in asymptomatic cases [23-25]. However, a recent RCT proved that asymptomatic primary tumor resection does not contribute to an improvement in OS in comparison with chemotherapy alone . In the RCT, some patients in the chemotherapy arm had to receive a surgical approach due to subsequent primary tumor symptoms. In this context, primary tumor resection of stage IV CRC would be less beneficial for prolonging OS, as long as the disease is not symptomatic.
On the other hand, the treatment for symptomatic primary tumors is more complicated, and patients may require interventions in order to proceed to the next treatment or palliation. The most effective option for obstructive and symptomatic stage IV CRC is still a topic of debate. Emergent surgical approaches have been reported to present a high risk for morbidity and mortality, mainly because patients are often already in a challenging physical condition [27-29]. In comparison with emergent surgery, SEMS is considered to be a useful method to overcome the symptoms of obstructive CRC [12, 13]. The advantages of SEMS over emergent operations include an improved 30-day mortality, lower morbidity and stoma creation rates, shorter duration of hospitalization, and earlier initiation of chemotherapy, while the negative aspects include the possibility of perforation related to the procedure or a slightly lower success rate.
After SEMS placement for stage IV CRC, some previous reports described that subsequent chemotherapy without resection of primary tumor could be introduced as long as the patient’s physical status was tolerable [15-17, 30, 31]. However, aggressive chemotherapy, including treatment with targeted agents such as bevacizumab, can cause late complications related to primary tumor with SEMS, such as perforation, stent migration, or re-obstruction, which appear in approximately 20% of the cases. Since a certain number of patients eventually need to undergo surgical intervention or, in the worst-case scenario, experience a life-threatening condition, the long-term use of SEMS under systemic chemotherapy would not be completely safe.
Quality of life (QOL) should also be focused on in the treatment of stage IV CRC. Laparoscopic surgery for colon cancer has been shown as a better option than open surgery with regard to the short- and long-term QOL, because of a quicker recovery, less pain, or better cosmesis [32, 33]. As for decompression stoma, it is a useful option to relieve the symptoms of obstructive CRC, however the deterioration of QOL associated with this stoma has been problematic, especially among older populations [34, 35]. From these points of view, SEMS as a BTS for stage IV CRC would be superior to primary resection in QOL, due to higher frequency of laparoscopic surgery, and lower rate of stoma creation.
Considering these concerning aspects, SEMS has been used as a bridge to elective surgery for the treatment of obstructive and symptomatic stage IV CRC in our department. This strategy would prevent the late complications of SEMS placement, potentially precluding the patients’ ability to receive or continue systemic chemotherapy; therefore, subsequent chemotherapy with targeted agents could be safely introduced. In the present study, no patients experienced later complications associated with primary tumors, which may have caused critical problems. Consequently, the 3-year overall survival in the SEMS group was comparable to that in the PR group.
The present study had several limitations. First, this was a single-institutional, retrospective study. Therefore, the development of chemotherapy possibly affected the outcome of the patients. However, in the present study, there was no significant difference between the two groups in the parameters related to chemotherapy. Second, both groups included a few cases with resectable metastatic sites, such as liver or lung metastases, which may have influenced the long-term outcomes. Third, this strategy may delay the initiation of systemic chemotherapy in comparison with emergent or urgent surgery or SEMS placement alone. At this moment, it is still unclear whether a delay in chemotherapy can influence long-term outcomes. In addition, it is possible that a small percentage of patients with stage IV obstructive CRC are unresectable. Three cases of unresectable CRCs were treated in our institution during the study period, and these patients underwent only decompression stoma. These cases would require different treatment strategies. Finally, since there is a major limitation that the small number of patients did not allow sufficient statistical power, further study is warranted.