Authors' objectives

To evaluate the value of intensive follow-up versus no follow-up after resection for colorectal cancer.

Searching

MEDLINE was searched for studies published between 1972 and 1996. A manual search of the references of retrieved articles was also conducted.

Study selection

Assessment of study quality

The authors do not state that they assessed validity.

Data extraction

The authors do not state how the data were extracted for the review, or how many of the authors performed the data extraction.

Methods of synthesis

Results of the review

There were 2 randomised controlled trials (RCTs) and 3 comparative-cohort studies (2,005 patients), 11 single-cohort studies of intense follow-up (5,472 patients), and 3 single-cohort studies of traditional follow-up (1,169 patients). (Note: 2 RCTs were excluded for the reasons that only preliminary results were reported or there were no data on the number of patients in the different groups.)

Based on 2 RCTs and 3 comparative cohort studies, the cumulative 5-year survival was 1.16 times higher in the intensively followed group (p=0.003). Also, there were 2.15 times more curative re-resections performed for recurrent cancer in those patients undergoing intensive follow-up (p=0.0001). Those patients in the intensive follow-up group with a recurrence had a 3.62 times higher survival rate than the control (p=0.0004). The results from the 14 single-cohort studies supported the findings of the meta-analysis.

Authors' conclusions

Intensive follow-up detected more recurrent cancers at a stage amenable to curative resection. This resulted in an improvement in survival of recurrences and an increased overall 5-year cumulative rate of survival.

CRD commentary

The inclusion criteria were clearly described and the details of the included studies were presented. The literature search was not comprehensive, ignoring many other databases. The authors discussed the importance of outcome measures other than the overall 5-year survival rate. However, they did not recognise that the survival rates after recurrence cannot be reliably compared between two groups because of lead time bias. That is, even if the survival of patients with recurrent cancer is not improved by re-resection, the survival rate of patients in whom the recurrence was diagnosed early will be higher than those in whom the recurrence was diagnosed late. Therefore, the most valid outcome measure should be the overall 5-year survival rate.

In this review, the results of 2 RCTs and 2 non-RCTs were combined. One non-RCT did not report the 5-year survival data. The relative rates for 5-year survival were estimated by the 2 RCTs as 1.11 (p=0.68) and 1.13 (p=0.43), which were smaller than those estimated by the 2 non-RCTs (1.17 and 1.16). It is well known that treatment effects tend to be overestimated by poorly designed studies and, therefore, the results from the RCTs may be more believable. In addition, we need to consider the potential bias due to the selective publication of positive findings. It is also likely that studies that were excluded on account of having no data were negative.

The effect of intensive follow-up after colorectal resection may, therefore, have been overstated in the review's conclusion.

Implications of the review for practice and research

The authors did not state any implications for practice or further research.

Bibliographic details

Rosen M, Chan L, Beart R W, Vukasin P, Anthone G. Follow-up of colorectal cancer: a meta-analysis. Diseases of the Colon and Rectum 1998; 41(9): 1116-1126. [PubMed: 9749495]

Indexing Status

Subject indexing assigned by NLM

MeSH

Adult; Aged; Aged, 80 and over; Colorectal Neoplasms /diagnosis /mortality /surgery; Female; Follow-Up Studies; Humans; Male; Middle Aged; Neoplasm Recurrence, Local /diagnosis /mortality /surgery; Reoperation; Survival Rate

AccessionNumber

11998001636

Database entry date

30/11/1999

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.