In the present study, to clarify the technical and oncological safety of laparoscopic surgery for colorectal cancer in the elderly, we compared the short- and long-term outcomes between the elderly patients in the laparoscopic surgery and open surgery groups, and the non-elderly patients in the laparoscopic surgery group. The results of the comparison between the laparoscopic surgery and open surgery groups of elderly patients showed that the intraoperative blood loss and incidence of postoperative complications were significantly lower in the laparoscopic group, and there were no differences in long-term outcomes between the two groups. When comparing the elderly and non-elderly laparoscopic surgery groups, the operation time was significantly shorter in the elderly group. In terms of long-term outcomes, although the elderly group had shorter OS, there was no difference in DSS between the two groups. These results suggest that laparoscopic colorectal surgery is less invasive than open surgery and is oncologically safe for elderly patients and for younger patients.
As shown in previous reports, laparoscopic colorectal surgery for elderly patients had advantages in short-term outcomes such as intraoperative blood loss, time to normal bowel function, and the length of hospital stay, similar to those in younger patients [15, 16]. However, our results showed that there was no advantage related to length of hospital stay in the laparoscopic group. This finding might have been caused by the lack of a clinical pathway system in our department. Because there was no clinical pathway system into our department, we might not have recommended that elderly patients be discharged from hospital, despite the early recovery of the patients in the laparoscopic group. The fact that there was also no difference in the postoperative course between the elderly and non-elderly patients in our study supports our view.
In relation to postoperative complications, some of the previous studies in elderly patients have reported the rates of morbidity in laparoscopic and open surgery to be similar [17, 18]. In contrast, other studies have shown that the rate of overall morbidity was lower in laparoscopic surgery than in open surgery [19–23]. Kennedy et al. reported that open surgery was one of the factors associated with an increased risk of complications in multivariate analysis using the database of the American College of Surgeons for elderly patients with colon cancer . We also observed a lower rate of overall morbidity in the laparoscopic group than that in the open group. However, it is still controversial whether laparoscopic colorectal surgery for elderly patients is as safe as it is in non-elderly patients. It is general knowledge that the incidence of postoperative complications causing a serious condition after major digestive surgery is considered to be higher in elderly patients because of the reduced functional potential of their organs and having significant age-related comorbidities such as cardiovascular and pulmonary disease [25–27]. Hermans et al. also reported that the incidence of complications in elderly patients was significantly higher than that in younger patients . However, Tokuhara et al. reported in a prospective cohort study that there were no differences between the elderly and younger patients in the incidence of postoperative complications after laparoscopic colorectal surgery . Kahn et al. found that older age is not independently associated with complications after surgery for colorectal cancer . Our results also showed that the rate of postoperative complications in the elderly patients did not increase compared with that in the non-elderly patients, in spite of the higher status of ASA-PS and the greater number of comorbidities in the elderly patients. These results suggest that laparoscopic colorectal surgery is as equally safe for elderly patients as it is for younger patients.
Regarding the long-term outcomes in this study, no significant differences in OS and DSS were shown between the laparoscopic and open group of elderly patients. These results were consistent with previous randomized control trials in non-elderly patients between laparoscopic and open surgery [31–33]. Niitsu et al. also reported that laparoscopic surgery for elderly colorectal cancer patients with poor PS was not inferior to open surgery in terms of survival . We also believe that laparoscopic surgery for colorectal cancer has equivalent oncological safety to that of open surgery among elderly patients. However, there have been only a few reports comparing long-term outcomes of laparoscopic colorectal surgery between elderly and non-elderly patients. Tokuhara et al. reported that there were no differences in recurrence-free survival and OS between elderly (≥ 75 years) and non-elderly (< 75 years) patients in a prospective cohort study . Jeong et al. reported that there was no difference between two groups in 3-year disease-free survival, although 3-year OS in the group aged ≥ 75 years was lower than that of the younger group . The present study also found that only OS in the elderly patients was lower than that in the non-elderly patients. The main reason is that elderly patients die because of diseases other than colorectal cancer. We did not find any significant differences in DSS between the elderly and non-elderly patients, so we believe that laparoscopic colorectal surgery for elderly patients is not inferior to that for non-elderly patients in terms of oncological safety.
There are some limitations in this study. First, this was a single-center, retrospective study. Second, there was selection bias in regard to the choice of the operation method in our study because it differed depending on the time period. Laparoscopic colorectal surgery for elderly patients was indicated in 50% of patients in 2007, whereas this ratio increased to 78% in 2014 in the present study. Lastly, differences in patient characteristics between the elderly and non-elderly patients, such as in TNM stage and perioperative chemotherapy, may also be a problem. It was difficult to apply the case-matching study due to insufficient sample size in this study. In the future, a large-scale multicenter prospective randomized controlled study is necessary.
In conclusion, laparoscopic colorectal surgery for elderly patients aged ≥ 80 years was less invasive and technically safer than open surgery and provided a surgical cure as it did for non-elderly patients. From the results of our study, we consider laparoscopic colorectal surgery to be an optimal procedure for elderly patients with colorectal cancer. To confirm our opinion, a multi-center prospective study with larger sample size would be required in the near future.