Purpose: Although multiple primary colorectal cancer
has been recognized as a significant clinical entity, its
clinical and pathological features and its prognosis are
still controversial. The purpose of this study was to clarify
clinical and pathological features of multiple primary colorectal
cancer.
Materials and Methods: Among 1669 patients who underwent
surgery for primary colorectal cancer from
January 1997 to June 2005, 26 patients (1.6%) with multiple
primary colorectal cancer were identified. We reviewed
clinical characteristics including diagnostic interval,
lesions, operating methods, and TNM stage, and we
defined the index lesion as the most advanced lesion
among the synchronous lesions. For the purposes of the
study, the colon and rectum were classified into three
segments. The right-side colon included the appendix,
cecum, ascending colon, hepatic flexure, and transverse
colon, and the left-side colon included the splenic flexure,
descending colon, and sigmoid colon.
Results: Of the 26 patients with multiple primary colorectal
cancers, nineteen patients were male and seven
patients were female, with a mean age of 61.5 years.
Nineteen patients had synchronous colorectal cancers
and seven patients had metachronous colorectal cancers.
In the metachronous cases, the mean diagnostic
interval was 36.8 months. The site of the first lesion in
metachronous colorectal cancers was the right colon in
five cases (71.4%) and the left colon in two cases
(28.6%), and the site of the second lesion was the rectum
in six cases (55.5%), the right colon in three cases
(33.3%), and the left colon in one case. The TNM stage of
the second lesions in the metachronous colorectal cancers
was stage II in four cases (57.1%), stage III in one
case (14.3%), and stage IV in one case (14.3%). For the
synchronous colorectal cancers, the operation methods
were single-segment resection combined with endoscopic
mucosal resection in five cases (26.3%), single-
segment resection alone in six cases, two-segment
resection in six cases, and total colectomy in two cases.
Conclusion: In metachronous colorectal cancers, the
secondary lesions were later-stage cancer. Therefore,
careful postoperative follow-up is necessary for patients
who have undergone surgery for colorectal cancers.
Further study of therapeutic modalities is important for
synchronous colorectal cancers.
Purpose: Although multiple primary colorectal cancer
has been recognized as a significant clinical entity, its
clinical and pathological features and its prognosis are
still controversial. The purpose of this study was to clarify
clinical and pathological features of multiple primary colorectal
cancer.
Materials and Methods: Among 1669 patients who underwent
surgery for primary colorectal cancer from
January 1997 to June 2005, 26 patients (1.6%) with multiple
primary colorectal cancer were identified. We reviewed
clinical characteristics including diagnostic interval,
lesions, operating methods, and TNM stage, and we
defined the index lesion as the most advanced lesion
among the synchronous lesions. For the purposes of the
study, the colon and rectum were classified into three
segments. The right-side colon included the appendix,
cecum, ascending colon, hepatic flexure, and transverse
colon, and the left-side colon included the splenic flexure,
descending colon, and sigmoid colon.
Results: Of the 26 patients with multiple primary colorectal
cancers, nineteen patients were male and seven
patients were female, with a mean age of 61.5 years.
Nineteen patients had synchronous colorectal cancers
and seven patients had metachronous colorectal cancers.
In the metachronous cases, the mean diagnostic
interval was 36.8 months. The site of the first lesion in
metachronous colorectal cancers was the right colon in
five cases (71.4%) and the left colon in two cases
(28.6%), and the site of the second lesion was the rectum
in six cases (55.5%), the right colon in three cases
(33.3%), and the left colon in one case. The TNM stage of
the second lesions in the metachronous colorectal cancers
was stage II in four cases (57.1%), stage III in one
case (14.3%), and stage IV in one case (14.3%). For the
synchronous colorectal cancers, the operation methods
were single-segment resection combined with endoscopic
mucosal resection in five cases (26.3%), single-
segment resection alone in six cases, two-segment
resection in six cases, and total colectomy in two cases.
Conclusion: In metachronous colorectal cancers, the
secondary lesions were later-stage cancer. Therefore,
careful postoperative follow-up is necessary for patients
who have undergone surgery for colorectal cancers.
Further study of therapeutic modalities is important for
synchronous colorectal cancers.