gms | German Medical Science

Background: Rectal cancer is a frequently diagnosed tumor worldwide. Its curative treatment involves radical surgical resection of the tumor. In the past, open surgery was the first choice for rectal resections, and even today, many surgeons still prefer the conventional approach. Nevertheless, various studies proofed the oncologic safety of laparoscopic resection and have shown its noninferiority or even slight superiority to the open approach. Until now, there does not exist a clear recommendation on whether age should influence the choice of the surgical approach.

Research question: It is known that age can have considerable influence on the perception of different therapeutic modalities. Based on a large pooled database of German cancer registries, the present study investigates whether laparoscopy and laparotomy for rectal cancer are equally suitable in all age groups in terms of short- and long-term survival.

Methods: This population-based retrospective cohort study compared outcomes of laparoscopic and open surgery in rectal cancer patients. Perioperative mortality, 5-year overall, relative, and recurrence-free survival rates were analyzed separately for three age groups (< 60 years, 60–69 years, 70–79 years). Data originate from 30 regional German cancer registries that cover approximately one quarter of the German population. All primary nonmetastatic rectal adenocarcinoma cases with surgery between 2005 and 2014 were eligible for inclusion. To compare survival rates, Kaplan–Meier analysis, a relative survival model, and multivariable Cox regression were used; a sensitivity analysis assessed bias by exclusion.

Results: Finally, 10754 patients fulfilling all inclusion criteria without missing data in important variables were included in the analysis. The mean laparoscopy rate was 23.0% and increased over time. Uni- and multivariable regression analysis of 30-day postoperative mortality revealed advantages for laparoscopically treated patients, although the significance level was not reached in any age group (for age group 70–79, it was missed only slightly: odds ratio, OR 0.559; 95% confidence interval, 95% CI 0.296–1.058). Regarding 5-year overall survival, laparoscopy generally seems to be the superior approach, whereas for recurrence-free survival patients under 60 years benefited more from the minimally invasive approach than older patients (< 60 years: hazard ratio, HR 0.703, 60–69 years: HR 0.787, 70–79 years: HR 0.923). The sensitivity analysis revealed that included patients did not have a significant advantage over patients excluded due to missing data in terms of 30-day postoperative mortality. Looking at 5-year overall survival rates, included patients did have a slightly superior survival rate compared to excluded patients (79.5 vs. 78.1%, p=0.017).

Discussion: Concerning short-term outcomes, laparoscopic surgery patients in this study had a lower postoperative mortality rate in all age groups. However, the effect size was only moderate and the significance level was not reached in any age group. A possible reason for the minor advantage of the minimally invasive surgical approach could be the lower postoperative complication rate. A significant advantage of laparoscopy could be observed for overall survival in all age groups 5 years after surgery. Taking a closer look at the actual effect sizes after adjustment for confounders, an age-dependent gradient can be seen for recurrence free survival. In the long term, young people obviously benefit most from minimally invasive surgery, while survival and recurrence patterns in older patients seem to depend less on the surgical approach. Future research is indispensable to further investigate the reasons for this observation. The large sample is a considerable strength of this study since all results are based on representative data from 30 regional cancer registries. Nevertheless, some limitations must be considered when interpreting the results presented in this study. Unfortunately, information on nononcologic comorbidities is lacking. However, there is evidence that stratifying by age, as it was done in this study, may partly account for this shortage.

Practical implication: Laparoscopic rectal cancer surgery can be considered safe in daily clinical practice. Laparoscopy shows similar results to the open approach in terms of postoperative mortality in all age groups. Concerning long-term outcomes, younger patients benefitted most from the minimally invasive approach. Increased use of laparoscopy for rectal cancer should be considered in this group.