Improved survival for rectal cancer compared to colon cancer: the four cohort study.
BACKGROUND
Colorectal cancer (CRC) is the third most common cancer worldwide. This study was undertaken to evaluate survival outcomes and changes of disease outcomes of CRC patients over the last decades.


METHODS
A retrospective analysis of CRC patients in Christchurch was performed in four patient cohorts at 5 yearly intervals; 1993-94, 1998-99, 2004-05 and 2009. Data on cancer location, stage, surgical and oncological treatment and survival were collected. Univariate, multivariate and Kaplan-Meier survival analysis were performed.


RESULTS
There were 1391 patients (355, 317, 419 and 300 per cohort), 1037 colon and 354 rectal cancers, respectively. For colon cancer, right-sided cancers appeared more common in later cohorts (P = 0.01). There was a significant decrease in the number of permanent stomas for colon cancer patients (P = 0.001). There was an analogous trend for rectal cancers (P = 0.075). More CRC patients with stage IV disease were treated surgically (P = 0.001) and colon cancer stages I and II tended to have increased survival if operated by a colorectal surgeon (P = 0.06). Oncology referrals have increased remarkably (P = 0.001). Overall 56% of patients were alive at 5 years however rectal cancer patients had significantly better 5-year survival than those with colon cancer (P < 0.05).


CONCLUSIONS
This four cohort study shows that modern CRC survival continues to improve and is comparable to international standards. Furthermore, rectal cancer patients have a better 5-year survival than colon cancer patients. The improved survival with early stage colon cancers operated on by specialist colorectal surgeons needs further exploration.
Colorectal Unit, Department of Surgery, Christchurch Hospital, Christchurch, New Zealand.
Pamela
P
Buchwald
Colorectal Unit, Department of Surgery, Christchurch Hospital, Christchurch, New Zealand.
Claire
C
Hall
Colorectal Unit, Department of Surgery, Christchurch Hospital, Christchurch, New Zealand.
Callum
C
Davidson
Colorectal Unit, Department of Surgery, Christchurch Hospital, Christchurch, New Zealand.
Liane
L
Dixon
Colorectal Unit, Department of Surgery, Christchurch Hospital, Christchurch, New Zealand.
Bruce
B
Dobbs
Department of Oncology, Christchurch Hospital, Christchurch, New Zealand.
Bridget
B
Robinson
Colorectal Unit, Department of Surgery, Christchurch Hospital, Christchurch, New Zealand.
Frank
F
Frizelle
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017024:Chemotherapy, Adjuvant; D003110:Colonic Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009520:New Zealand; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D012017:Referral and Consultation; D012189:Retrospective Studies; D015996:Survival Rate
cohort; colorectal cancer; malignancy; outcomes