Cancer staging and survival in colon cancer is dependent on the quality of the pathologists’ specimen examination
Introduction
The staging of patients operated for colon cancer is a determining factor for further oncological treatment and for prediction of long-term survival. Different staging systems for classification have been used since Dukes introduced his classification system for rectal cancer in 1932 [1], and most commonly used today is the TNM classification [2]. As several studies have shown that postoperative chemotherapy in patients with a stage III colon cancer has a beneficial effect on survival 3, 4, 5, it is even more important to improve not only the surgical technique, but also sampling of nodes and staging. There appears to be a breakpoint in the number of lymph nodes examined that will properly determine the proportions of tumour stages II and III [6].
During the past decade, the surgeon and the surgical technique have been in focus in research concerning quality and survival in colorectal cancer 7, 8, 9, 10, 11. An important recent step in attempts to further improve the surgical quality in rectal cancer has been the provision for immediate feedback from the pathologist to the surgeon [12]. Important advances have also been made in pre- and post-operative oncological treatment 3, 13. However, a prerequisite for a proper decision by the oncologists about postoperative treatment is a valid report from the pathologist after examination of the resected specimen. Several attempts have been made to estimate the number of nodes necessary to examine for correct staging. Between 6 and 18 nodes have been recommended 14, 15, 16. According to the World Congress of Gastroenterology (Sydney, Australia, 1990) [6], a minimum of 12 lymph nodes should be examined for correct classification of tumours as stage II.
In population-based studies, the proportions of colon cancer in stages II and III are approximately 40% and 30% 17, 18, 19, with survival rates varying between 50–80% and 30–60%, respectively. However, there are reasons to believe that the proportion of stage III tumours is in fact higher than has been reported, on account of inadequate examination of lymph node metastases. During the past decade it has been considered a gold standard to offer adjuvant chemotherapy to patients operated on for a colon cancer stage III, as several studies have shown that this increases survival by approximately 10%, whereas this is not yet the case in stage II where uncertainties about the value of adjuvant chemotherapy still exist 3, 5, 20, 21. It is therefore of immediate importance to identify all patients with lymph node metastasis.
The aim of this study was to investigate the variability in the accuracy of pathology reports, with special attention to differences between pathology departments and to their compliance to regional guidelines. Since the number of nodes is influenced by preoperative radiotherapy, frequently used for rectal cancer [13], and a clear survival benefit of postoperative chemotherapy has been found for colon, but not for rectal cancer, our investigation was focused solely on colon cancer. Our primary hypothesis was that the differences in quality between pathology departments influence the classification of tumours into stages and that stage dependent outcome was influenced by the quality.
Section snippets
Materials and methods
Since 1997 all colon cancers (adenocarcinoma) in the Swedish health care region of Uppsala/Örebro (population 1.9 million in 2001) have been reported to a population-based register run by the Regional Oncologic Centre (ROC). During this period, common regional guidelines for diagnosis, staging and treatment of colorectal cancer have been settled and agreed upon in consensus, by surgeons, oncologists and pathologists. The guidelines include, among others, recommendations concerning the
Results
Characteristics of the included patients are listed in Table 1. In 64% (n = 2390) of the cases, the number of lymph nodes examined was given in the pathology report. In these, the median overall number of lymph nodes examined was 8 (mean 9.4), with a variation in medians between pathology departments from 6 to 12 lymph nodes (Table 2). During the study period, an improvement was seen regarding the proportion of reports where the number of nodes examined was given (20% in 1997 and 90% in 2002) as
Discussion
In the present population-based study, the number of nodes examined was recorded in 64% of the cases and only 19% of the examinations fulfilled the recommendations regarding a minimum of 12 examined nodes and that the number examined should be stated.
Our data were taken from the colon cancer registry, and not directly from the pathology report. However, a previous validation of the registry [23] showed that missing data (regarding number of lymph nodes examined) is not due to improper reports
Conflict of interest statement
None declared.
Acknowledgements
This study was approved by the Regional Oncological Centre, University Hospital, Uppsala, with special help from Hans Garmo, statistician. Financial support was obtained from the Swedish Cancer Society (Grant No. 1921-B04-22xAC).
References (31)
Quality assurance in surgical oncology. Colorectal cancer as an example
Eur J Surg Oncol
(2003)- et al.
Elective surgery for colorectal cancer in a defined Swedish population
Eur J Surg Oncol
(2004) The classification of cancer of the rectum
J Pathol Bacteriol
(1932)- American Joint Committee on Cancer. Cancer staging manual. 5th ed. 2003. p....
- et al.
A systematic overview of chemotherapy effects in colorectal cancer
Acta Oncol
(2001) - et al.
Adjuvant 5FU plus levamisole in colonic or rectal cancer: improved survival in stages II and III
Br J Cancer
(2001) - et al.
Pooled analysis of fluorouracil-based adjuvant therapy for stage II and III colon cancer: who benefits and by how much?
J Clin Oncol
(2004) - et al.
Clinicopathological staging for colorectal cancer: an International Documentation System (IDS) and an International Comprehensive Anatomical Terminology (ICAT)
J Gastroenterol Hepatol
(1991) - et al.
Influence of hospital- and surgeon-related factors on outcome after treatment of rectal cancer with or without preoperative radiotherapy
Br J Surg
(1997) - et al.
Changing strategy for rectal cancer is associated with improved outcome
Br J Surg
(1999)
A national strategic change in treatment policy for rectal cancer-implementation of total mesorectal excision as routine treatment in Norway. A national audit
Dis Colon Rectum
Impact of the introduction and training of total mesorectal excision on recurrence and survival in rectal cancer in The Netherlands
Br J Surg
Macroscopic evaluation of rectal cancer resection specimen: clinical significance of the pathologist in quality control
J Clin Oncol
A systematic overview of radiation therapy effects in rectal cancer
Acta Oncol
Colorectal adenocarcinoma: quality of the assessment of lymph node metastases
Dis Colon Rectum
Cited by (99)
The extracellular matrix in colorectal cancer and its metastatic settling – Alterations and biological implications
2022, Critical Reviews in Oncology/HematologyCitation Excerpt :The number of regional lymph nodes in the specimen that should be examined have been discussed, concluding that fewer than 12 examined lymph nodes implies a risk of staging the disease too low but also as a risk factor for relapse. Further, fewer than 12 examined lymph nodes have been associated with a higher risk of death compared with examining more than 12 lymph nodes (Jestin et al., 2005; Lykke et al., 2019). One function of the lymphatic system is to transport proteins, extravasal fluid and cells from tissues back into the circulation.
Lymphatic spread, nodal count and the extent of lymphadenectomy in cancer of the colon
2014, Cancer Treatment ReviewsCitation Excerpt :The use of a standardized protocol to evaluate CC specimens is recommended.52,98 Data from the CC register of the Uppsala/Örebro, Sweden, health care region showed that only for 64% of the CC cases the LNC was recorded.99 A population-based study of 8,848 colorectal cancer patients pointed out that a template ensuring the inclusion of important pathology characteristics results in increased LNC.84