A high tumour-stroma ratio (TSR) in colon tumours and its metastatic lymph nodes predicts poor cancer-free survival and chemo resistance

PURPOSE

Despite known high-risk features, accurate identification of patients at high risk of cancer recurrence in colon cancer remains a challenge. As tumour stroma plays an important role in tumour invasion and metastasis, the easy, low-cost and highly reproducible tumour-stroma ratio (TSR) could be a valuable prognostic marker, which is also believed to predict chemo resistance.

METHODS

Two independent series of patients with colon cancer were selected. TSR was estimated by microscopic analysis of 4 µm haematoxylin and eosin (H&E) stained tissue sections of the primary tumour and the corresponding metastatic lymph nodes. Patients were categorized as TSR-low (≤ 50%) or TSR-high (> 50%). Differences in overall survival and cancer-free survival were analysed by Kaplan-Meier curves and cox-regression analyses. Analyses were conducted for TNM-stage I-II, TNM-stage III and patients with an indication for chemotherapy separately.

RESULTS

We found that high TSR was associated with poor cancer-free survival in TNM-stage I-II colon cancer in two independent series, independent of other known high-risk features. This association was also found in TNM-stage III tumours, with an additional prognostic value of TSR in lymph node metastasis to TSR in the primary tumour alone. In addition, high TSR was found to predict chemo resistance in patients receiving adjuvant chemotherapy after surgical resection of a TNM-stage II-III colon tumour.

CONCLUSION

In colon cancer, the TSR of both primary tumour and lymph node metastasis adds significant prognostic value to current pathologic and clinical features used for the identification of patients at high risk of cancer recurrence, and also predicts chemo resistance.

Tumour Budding and Tumour Stroma Ratio are Reliable Predictors for Death and Recurrence in Elderly Stage I Colon Cancer Patients

AIM

Tumour budding (BD) and Tumour stroma ratio (TSR) are considered valuable survival parameters for colon cancer (CC), but it is still unclear whether these parameters predict a poor prognosis. This study aimed to determine the survival effect of TB and TSR in elderly stage I CC patients.

METHODS

We evaluated these parameters in eighty-eight stage I CC patients who underwent surgical treatment alone between 1998 and 2015. The relationship between these parameters and age was investigated. Model A was used for methodology.

RESULTS

In elderly patients (≥68), these parameters obtained more successful results for following analysis: relationship between prognostic factors [lymphatic invasion (BD, p = 0.003; TSR, p = 0.003), perineural invasion (BD, p = 0.016; TSR, p = 0.004), tumour deposites (BD, p = 0.005; TSR, p = 0.033), MSI (BD, p=0.031; TSR, p=0.012), etc.], correlation of estimates (BD, r=0.724; TSR, r=0.703), and reproducibility of study (BD [Kappa (ĸ)]=0.53-0.75; TSR (ĸ) =0.56-0.71). Also, the cut-off values were useful for BD (area of under ROC (AUC)=0.816 [0.707-0.925]) and TSR (AUC=0.810 [0.697-0.924]). In univariate analysis, in elderly patients, these parameters had a poor 5-year survival for RFS (p<0.001[BD], p=0.001[TSR]), OS (p<0.001[BD], p=0.005[TSR]), and LR (p=0.008[BD], p=0.034[TSR]). Multivariate analysis confirmed that these parameters are independent worse predictors for RFS (BD: 1.42[HR], p=0.002; TSR: 1.50[HR], p=0.001), OS (BD: 1.38[HR], p=0.014; TSR: 1.42[HR], p=0.005), and LR (BD: 1.61[HR], p=0.034) in elderly patients.

CONCLUSIONS

Our results confirm that BD and TSR are reliable indexes for poor survival in elderly stage I CC patients. We recommend using model A for successful results and standardization.

Does heterogeneity matter in the estimation of tumour budding and tumour stroma ratio in colon cancer?

Background

Tumour budding (TB) and Tumour Stroma Ratio (TSR) may be rewarding in the treatment stratification of patients with stage II colon cancer. However, lack of standardization may exclude these parameters from being used in a clinical setting. The purpose of this methodologic study was to compare stereology with semi-quantitative estimations of TSR, to investigate the intra-tumoural heterogeneity of TB and TSR, and to assess the intra- and inter-observer agreement.

Methods

Three paraffin embedded tumour blocks, one of them representing the deepest invasive front, were selected from each of 43 patients treated for stage II colon cancer. TSR was estimated in H&E sections semi-quantitatively using conventional microscopy, and stereologically on scanned slides, using the newCAST stereology platform. TB was scored across 10 high power fields at the invasive front in cytokeratin AE1/AE3 stained sections.

Results

Subjective, semi-quantitative estimates of TSR significantly correlated to the stereological estimates, with the best correlation found for sections with the deepest invasive tumour penetration (σ = 0.621, p < 0.001). Inter-observer agreement was moderate to substantial for both TB (Κappa = 0.46–0.73) and TSR (Κappa = 0.70–0.75).

The Intraclass correlation coefficient (ICC) for TSR varied from 0.322 based on stereological hotspot estimation to 0.648 for the semi-quantitative evaluation. For TB, ICC varied from 0.646 based on continuous data to 0.698 based on categorical data (cut-off: 10 buds). Thus, the intra-tumoural heterogeneity for both TB and the semi-quantitative estimation of TSR was low.

Conclusion

We recommend using only one tissue section representing the deepest invasive tumour area for estimation of TSR. For TB we recommend using one tissue section; however due to low representation of high-budding tumours, results must be considered with caution.

Electronic supplementary material

The online version of this article (10.1186/s13000-018-0697-9) contains supplementary material, which is available to authorized users.

The prognostic value of tumour stroma ratio and tumour budding in stage II colon cancer. A nationwide population-based study

PURPOSE

High-risk patients with stage II colon cancer (CC) may benefit from adjuvant chemotherapy, but additional prognostic markers are needed for better stratification. We investigated the prognostic value of tumour stroma ratio (TSR) and tumour budding (TB).

METHODS

A nationwide population-based cohort of 573 patients with stage II CC was included. TSR was scored on hematoxylin and eosin sections as low TSR (> 50% stroma) and high TSR (≤ 50% stroma). TB was evaluated in hotspots on pan-cytokeratin stained sections in 10 high power fields (HPF) at the invasive front and classified by the mean number of buds per HPF as high grade budding (≥ 10 buds) or low-grade budding (< 10 buds). The prognostic value was investigated in Cox proportional hazard models for recurrence-free survival (RFS) and overall survival (OS).

RESULTS

Low TSR was associated with worse RFS (HR = 1.342 (95% CI 1.006-1.791), p = 0.045) and OS (HR = 1.376 (95% CI 1.016-1.862), p = 0.039). Furthermore, an association was found between low TSR and microsatellite stabile tumours (p < 0.001). The mean number of buds per HPF was associated to TSR with increasing number of buds related to a lower TSR (p = 0.026). No statistically significant prognostic impact of TB regarding OS or RFS was detected.

CONCLUSIONS

TSR provided valuable prognostic information, and adding TSR to the current risk stratification may contribute to better patient selection. The estimates of TSR and TB were found to be associated, but no prognostic value of TB was documented.