World Journal of Colorectal Surgery

ORIGINAL ARTICLE
Year
: 2019  |  Volume : 8  |  Issue : 2  |  Page : 40--43

Trends in survival after colorectal cancer surgery in an Australian regional hospital


Suat Chin Ng1, Douglas Stupart2, David Watters2,  
1 Faculty of Medicine, Dentistry and Health Science, University of Melbourne, Victoria, Australia
2 School of Medicine, Deakin University, Victoria, Australia

Correspondence Address:
Dr. Suat Chin Ng
11, 765 Doncaster Road, Doncaster, 3108, Melbourne, Victoria
Australia

Abstract

Background: Colorectal cancer (CRC) is the second most common cancer in Australia. Improvements in patient outcomes after resections for CRC have been reported in an Australian metropolitan hospital, but significant outcome variability exists between health systems and institutions. Objective: This study sought to determine whether changes in the management of CRC have translated into improved survival after surgery in an Australian regional hospital. Design: This is a retrospective study of a prospectively maintained database. Setting: This study was conducted in an Australian regional hospital. Patients and Methods: All patients who underwent surgery for CRC at our institution between January 2002 and December 2014 were studied. Demographic information, comorbidities, types of surgery performed, and tumor staging were recorded. Patients were followed up for life whenever possible. Survival analysis was done using the Kaplan–Meier method, and comparisons made using the Cox proportional-hazards method. Chi-squared test was used to compare categorical data and look at trends as appropriate. P ≤ 0.05 was considered statistically significant. Statistical analysis was done using Medcalc® (Mariakerke, Belgium) software. Main Outcome Measures: Primary outcome measures the survival trends for CRC patients in regional center, Victoria. Secondary outcomes measure the short-term results, including perioperative mortality and anastomotic leak rate. Sample Size: A total of 1079 patients who underwent surgery for CRC over 13 years were studied. Results: There were 744 colon cancer and 335 rectal cancer patients. The number of operations per year increased over time (P = 0.037). The median age was 72 years (range, 23–98) and this did not change over time (P = 0.67). There was also no temporal change in tumor stage distribution (P = 0.21) or in the proportion of emergency cases (P = 0.75), but the proportion of patients with severe comorbidities increased (P = 0.015). The perioperative mortality rate was 4.5%. The median survival after surgery by stage was 123 months (Stage I), 141 months (Stage II), 76 months (Stage III), and 17 months (Stage IV tumors). Over the study period, there were improvements in both perioperative mortality (P = 0.028) and long-term survival (P = 0.0025). Conclusion: Both short- and long-term survivals after surgery for CRC have improved in our institution. Limitation: Although a large regional cohort was analyzed, the study still has its own limitation, in that it is a retrospective single institute study.



How to cite this article:
Ng SC, Stupart D, Watters D. Trends in survival after colorectal cancer surgery in an Australian regional hospital.World J Colorectal Surg 2019;8:40-43


How to cite this URL:
Ng SC, Stupart D, Watters D. Trends in survival after colorectal cancer surgery in an Australian regional hospital. World J Colorectal Surg [serial online] 2019 [cited 2021 Sep 29 ];8:40-43
Available from: https://www.wjcs.us.com/text.asp?2019/8/2/40/261548


Full Text



 Introduction



Colorectal cancer (CRC) is the second most common cancer in Australia,[1] with increasing incidence, but decreasing overall mortality.[1] Improvements in patient care (chemoradiotherapy, surgical technique, and perioperative care) and earlier diagnosis have contributed to improved survival.[2]

Dent et al. have reported improvements in patient outcomes after resections for CRC[3],[4] in a large Australian metropolitan hospital, but significant outcome variability exists between health systems and institutions.[5],[6],[7]

The purpose of this study was to determine whether changes in the care of CRC patients have translated into improved short- and long-term survival after surgery in an Australian regional hospital.

 Patients and Methods



This is a retrospective study of a prospectively maintained database of all operations performed for CRC at the University Hospital Geelong (a regional teaching hospital in Victoria, Australia) from January 2002 to December 2014.

Data recorded included demographic information, comorbidities, types of surgery performed, and tumor staging. Local staging was confirmed pathologically in cases where the tumor was resected and radiologically and clinically in other cases.

Patients had lifelong clinical follow-up wherever possible. When patients were lost to clinical follow-up, attempts were made to contact the patient, his/her family, or general practitioner to find the patient or to confirm if and when she/he had died. One of the authors (S. N.) personally attempted to contact all patients whose survival status was uncertain. Follow-up was until at least December 31, 2015.

Survival analysis was done using the Kaplan–Meier method to allow for variable follow-up, and comparisons made using the Cox proportional-hazards method. Categorical data were compared using the Chi-squared test or Chi-squared test for trend as appropriate. P ≤ 0.05 was considered statistically significant. Statistical analysis was done using Medcalc® (Mariakerke, Belgium) easy-to-use statistical software.

Ethical approval for the study was from the Barwon Health Research Ethics, Governance, and Integrity Unit.

 Results



A total of 1079 patients underwent surgery for colorectal adenocarcinoma during the study period. A median of 80 (range 68–103) patients underwent surgery each year, with an increasing number of patients operated on annually over the study period [Figure 1]; correlation coefficient r = 0.58, P = 0.037]. Five patients were lost to follow-up.{Figure 1}

Demographics and tumor characteristics

Of the 1079 patients, 744 had surgery for colon cancer and 335 for rectal cancer. There were a total of 617 men and 462 women. The median age at surgery was 72 years (range 23–98), and the patients' age distribution has not changed over the study period (correlation coefficient r = 0.013, P = 0.67). Overall, 235/1079 (22%) patients underwent surgery as an emergency. The proportion of emergency operations varied over time, with a minimum of 11% in 2006 and a maximum of 31% in 2002, but with no significant temporal trend (P = 0.75, Chi-squared test for trend).

Patient comorbidities, classified according to the Charlson Comorbidity Index (CCI),[8] were grouped as mild (CCI scores of 1–2), moderate (CCI scores of 3–4), or severe (CCI scores ≥5). Overall, 408 (38%) patients had no comorbidities, 415 (39%) had mild, 192 (18%) had moderate, and 64 (6%) had severe comorbidities. The proportion of patients with severe comorbidities increased over the study period from 1/72 (1.4%) in 2002 to 9/95 (9.5%) in 2014 (P = 0.015, Chi-squared test for trend).

Overall, the number of tumors by stage were as follows: Stage I: 164 (15%); Stage II: 353 (33%); Stage III: 375 (35%); and Stage IV: 187 (17%). The stage distribution of cancers did not vary significantly through the study period (P = 0.21, Chi-squared test).

Trends in adjuvant therapy

Overall, 232/375 (62%) patients with Stage III cancers and 57/353 (16%) patients with Stage II cancers received adjuvant chemotherapy. There was no significant change over time in either group (P = 0.19 for Stage III and P = 0.61 for Stage II; Chi-squared test for trend). Palliative chemotherapy was given to 122/187 (65%) patients with Stage IV cancers, and this rate did not change significantly over time (P = 0.59, Chi-squared test for trend). Among patients with rectal cancers, 89/335 (27%) received neoadjuvant chemoradiotherapy. This rate increased significantly over time (P = 0.039, Chi-squared test for trend).

Short-term outcomes

Perioperative mortality (defined as death before discharge or within 30 days of surgery) occurred in 49/1079 (4.5%) patients during the study period. Perioperative mortality was higher for emergency cases (21/235 [8.9%]) than elective cases (28/844 [3.3%], P = 0.0009). At the beginning of the study period, there was a high perioperative mortality rate of 8% in 2002 and 14% in 2003. Perioperative mortality decreased over the study period overall [Figure 2], P = 0.028, Chi-squared test for trend].{Figure 2}

Of the 1079 patients, 837 underwent a resection and primary anastomosis. Anastomotic leaks occurred in 54/837 (6.5%) of patients, and there was no significant variation in this rate over time (P = 0.31, Chi-squared test).

Long-term survival

Kaplan–Meier estimates of long-term survival after surgery grouped by tumor stage are illustrated in [Figure 3]. Median survival after surgery was 123 months for patients with Stage I, 141 months for Stage II, 76 months for Stage III, and 17 months for Stage IV cancers. The Kaplan–Meier estimate of overall median survival was 87 months, and there was a significant improvement in survival over the study period (P = 0.0052, Cox proportional-hazards method [Figure 4]. Over the study period, long-term survival improved over time in patients with Stage I (P = 0.018) and Stage IV cancers (P = 0.0025) but remained constant for those with Stage II (P = 0.81) and Stage III cancers (P = 0.60, Cox proportional-hazards method). This improvement in long-term survival for Stage I and Stage IV was still apparent if patients who died perioperatively were excluded from the analysis (P = 0.38 and P = 0.011, respectively). Two-year survival after surgery grouped by tumor stage is shown in [Figure 5]. Although there appeared to be a trend toward increasing 2-year survival for patients with Stage IV tumors over the study period, this was not statistically significant (P = 0.094; Chi-squared test for trend). Nor was there any significant change in 2-year survival for Stage I (P = 0.17), Stage II (P = 0.84), and Stage III (P = 0.72) cancers or overall (P = 0.19; Chi-squared test for trend).{Figure 3}{Figure 4}{Figure 5}

 Discussion



Over the 13-year study period, we found significant improvements in short- and long-term survival for patients undergoing surgery for CRC at our institution. Perioperative mortality has halved between 2002 and 2014, and long-term survival has improved overall but most significantly in patients with metastatic (Stage IV) tumors. This improvement in survival has occurred despite an increasing proportion of comorbid patients undergoing surgery and despite there being no change in tumor stage at diagnosis over the study period.

A number of changes have been instituted in the Department of Surgery at University Hospital Geelong that may have contributed to the improvement in perioperative survival rates over the study period. In 2004, a formalized process of involuntary audit and feedback to individual surgeons was introduced in response to the high perioperative mortality that occurred in 2003. Since that time, the perioperative mortality rate has remained between 0% and 6% annually. This intervention in our institution has been described previously[9],[10] and has been shown to be beneficial nationally in Australia.[3] There has also been a significant shift toward surgical subspecialization within the department, more subspecialty trained colorectal surgeons have been recruited. Over 90% of elective surgery for CRC is now performed by the colorectal surgical unit. There has also been a significant increase in the overall volume of CRC surgery. Intensive care unit (ICU) capacity has increased, and the indications for admission to ICU postoperatively have become more liberal. The introduction of dedicated emergency theaters at UHG has previously been shown to improve the delivery of emergency surgery services generally.[11]

Approximately 60% of patients with Stage III CRC were given adjuvant chemotherapy, which is in keeping with Australian and international norms.[12],[13],[14] The significant improvement in long-term survival associated with adjuvant chemotherapy in this group of patients is well established,[15],[16] and it has been routinely offered (in the absence of prohibitively advanced age or comorbidities) throughout the study period. Similarly, the proportion of patients with metastatic disease who received palliative chemotherapy has not changed over time. The benefit of adjuvant chemotherapy in the setting of Stage II cancers remains controversial, and so it has seldom been offered at our institution.

The rates of administration of adjuvant and palliative chemotherapy have remained constant despite the introduction of colorectal multidisciplinary team meetings in 2006 (as previously described).[17] The choice of chemotherapy agents has, however, expanded over the study period. Specifically, bevacizumab became available in 2009, and cetuximab and panitumumab have been available since 2011. All of these agents have been shown to improve survival in selected patients with metastatic CRC.[18],[19],[20] The changes in systemic therapy for patients with metastatic disease provide the most likely explanation for the overall improvement in long-term survival (beyond the perioperative phase) in our institution over the study period.

It is difficult to draw clear causal conclusions from this study, as multiple changes have been made in our practice over the study period, and this is a retrospective audit with all of the limitations inherent in that methodology. It is encouraging, however, that the reported improvements in short- and long-term oncological outcomes have been replicated within our institution.

 Conclusion



Both short and long - term survival after surgery for colorectal cancer have improved in our regional institution. Results comparable to Australian and International standards.

Acknowledgment

General support by the Department of Surgery, University Geelong Hospital, is gratefully acknowledged.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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