Impact of inter-laboratory variation in detection of lymphovascular invasion (LVI) on treatment and oncological outcomes of T1 colorectal cancer (CRC) patients: a Dutch nationwide cohort study

Aims Lymphovascular invasion (LVI) plays an important role in determining the risk of lymph node metastasis (LNM) in T1 colorectal cancer (CRC) patients. The presence or absence of LVI guides treatment decisions and subsequently influences patient outcomes. However, the extent to which inter-laboratory variation in LVI detection affects treatment patterns and oncological outcomes is unclear. This study aimed to assess the impact of variation in detection of LVI among Dutch laboratories on the treatment and oncological outcomes of patients with T1 CRC.

Methods Pathology reports and clinical data of T1 CRC patients who underwent local resection between 2015 and 2019 were obtained from the Dutch nationwide pathology databank (Palga cohort). Laboratories were categorized as low, average, or high detectors based on their LVI detection rates. The impact of LVI detection practice on the rate of surgical resection after local resection and the proportion of lymph node metastasis-negative (LNM-) surgeries was evaluated. Second, the Dutch T1 CRC Working Group cohort, which includes extensive follow-up data, was used to assess the effect of LVI detection practice on the proportion of cancer recurrences in T1 CRC patients who did not undergo completion surgery. Multivariable logistic regression analyses and Cox proportional hazards regression were employed to study the association between LVI detection practice and the selected outcomes.

Results The Palga cohort consisted of 5,518 locally resected T1 CRCs. LVI detection rates varied among the pathology laboratories, ranging from 8.0% to 43.9%. Patients diagnosed in laboratories with a high LVI detection rate (>22.4%) exhibited significantly higher rates of surgical resection after local resection of T1 CRC compared to those diagnosed in laboratories with a low detection rate (adjusted odds ratio [aOR] 1.88; 95% confidence interval [CI] 1.52-2.32). Similarly, the proportion of LNM- surgeries was significantly higher in patients diagnosed in high LVI detection laboratories (aOR 1.73; 95% CI 1.39-2.15). Within the Dutch T1 CRC Working Group cohort, which included 1268 locally resected T1 CRCs, no significant difference was observed in the occurrence of cancer recurrences among patients diagnosed in laboratories with high detection rates compared to those with low detection rates (adjusted hazard ratio [aHR] 2.23; 95% CI 0.94-5.23).

Conclusions This study shows that a higher LVI detection rate does not lead to improved oncological outcomes and suggests that a greater number of patients are unnecessarily exposed to the potential side effects of oncological surgery. These findings emphasize the importance for clinicians to possess a comprehensive understanding of how LVI was detected and the factors influencing the pathologist's conclusions. By doing so, clinicians can weigh the actual risk of lymph node metastasis against the risk of surgical morbidity and mortality, while considering the individual preferences of the patient.

Publication History

Article published online:
15 April 2024