Simple Blood Markers May Predict Which Elderly Colon Cancer Patients Benefit from Chemotherapy

A routine blood test taken a few weeks after surgery could help oncologists decide which patients over 70 with stage III colorectal cancer are truly likely to benefit from adjuvant chemotherapy, according to a retrospective study conducted at Japan’s National Cancer Center Hospital and published in Annals of Gastroenterological Surgery. The research focused on two inexpensive immune and inflammatory measures, the lymphocyte-to-monocyte ratio (LMR) and the C-reactive protein-to-albumin ratio (CAR), and found that only patients with higher postoperative values of these markers showed significant survival gains from chemotherapy, while those with lower values derived little to no benefit.

Colorectal cancer remains one of the most common malignancies worldwide, and while radical surgery is highly effective when the disease has not spread to distant organs, stage III disease, defined by lymph node involvement, carries a recurrence rate of 20 to 30 percent. Adjuvant chemotherapy after surgery has been proven in randomized controlled trials to reduce this risk and improve survival. However, the picture becomes murkier in patients aged 70 and older. As people age, comorbidities accumulate and organ function declines, making chemotherapy harder to tolerate and raising the risk of serious adverse events. Notably, there is no consistent evidence that adding oxaliplatin provides additional benefit in this age group, suggesting that the therapeutic effect of adjuvant chemotherapy may be limited for many elderly patients.

This uncertainty creates a real clinical dilemma. Physicians must weigh the possibility of a survival benefit against the substantial burden chemotherapy can impose on an older body. The Japanese research team, led by Tomoya Tago and Yasuyuki Takamizawa, set out to determine whether simple blood-derived markers, calculated from tests already ordered in routine care, could identify which elderly patients are most likely to benefit from postoperative chemotherapy and which might safely avoid it.

The study included patients aged 70 or older who underwent radical resection of pathologically confirmed stage III colorectal adenocarcinoma at the National Cancer Center Hospital between January 2000 and December 2017. After excluding those with other primary cancers, prior neoadjuvant therapy, or incomplete data, 308 patients remained, of whom 177 received adjuvant chemotherapy and 131 did not. Because patients selected for chemotherapy were significantly younger and likely healthier than those who were not, the researchers used propensity score matching to balance the two groups on sex, age, body mass index, comorbidities, tumor location and stage, histology, and preoperative tumor marker levels. This produced 78 matched pairs with well-balanced baseline characteristics.

The survival benefit of adjuvant chemotherapy held up after matching. The five-year recurrence-free survival rate was 76.6 percent in the chemotherapy group versus 62.8 percent in the non-treatment group, with a hazard ratio of 0.537. Five-year overall survival was 84.1 percent versus 73.9 percent, with a hazard ratio of 0.495. Both differences were statistically significant, confirming that adjuvant chemotherapy remains worthwhile for properly selected elderly patients overall.

The most striking findings emerged when the researchers stratified the matched cohort by nine preoperative and postoperative immuno-nutritional and inflammatory markers, including the neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, prognostic nutritional index, geriatric nutritional risk index, controlling nutritional status score, Glasgow Prognostic Score, and modified Glasgow Prognostic Score. Two postoperative markers showed significant interactions with chemotherapy benefit: the lymphocyte-to-monocyte ratio and the C-reactive protein-to-albumin ratio.

In patients with a high postoperative LMR, defined by the study’s cut-off of 5.27, adjuvant chemotherapy produced a dramatic improvement. Five-year recurrence-free survival reached 84.4 percent in the treated group versus just 53.0 percent in the untreated group, a hazard ratio of 0.27. Overall survival showed an even starker contrast: 92.1 percent versus 68.0 percent, with a hazard ratio of 0.16. Yet in patients with a low postoperative LMR, chemotherapy provided essentially no advantage, with five-year recurrence-free survival of 69.2 percent versus 72.9 percent, and overall survival of 76.9 percent versus 80.4 percent, both comparisons statistically indistinguishable.

The CAR told a similar story. Patients with a high postoperative CAR, above the cut-off of 0.026, derived marked benefit from chemotherapy, with five-year recurrence-free survival of 79.0 percent versus 47.8 percent and overall survival of 88.0 percent versus 62.4 percent. In those with a low CAR, the survival curves of treated and untreated patients were nearly superimposable. The biological rationale is rooted in tumor-host interactions: lymphocytes mount anti-tumor immune responses and their preservation is associated with better drug responsiveness, whereas systemic inflammation, marked by elevated C-reactive protein relative to albumin, reflects a cytokine-driven state regulated by interleukin-1, interleukin-6, and tumor necrosis factor-alpha that generally portends poorer outcomes. Because postoperative samples in this study were collected uniformly four to eight weeks after surgery, once acute inflammatory responses from the operation had subsided, the markers likely captured the patient’s intrinsic baseline immunity at the moment chemotherapy would begin, rather than residual tumor-driven inflammation.

The clinical appeal of these markers lies in their simplicity and cost. Unlike circulating tumor DNA, which shows promise for predicting treatment efficacy but remains expensive and not yet widely implementable, LMR and CAR can be calculated from standard complete blood counts and chemistry panels already obtained in routine follow-up. The authors suggest that these values could serve as supplementary information alongside age, performance status, and comorbidities when the indication for adjuvant chemotherapy is being considered, helping individualize decisions rather than uniformly determine them.

The researchers acknowledge important limitations. The study was retrospective and single-center, so selection bias and institution-specific treatment practices cannot be fully excluded, and the derived cut-off values may not generalize elsewhere. Standardized comorbidity assessment tools such as the Charlson Comorbidity Index and Geriatric-8 were not consistently available, data on chemotherapy completion rates and adverse events were incomplete, and molecular information on RAS, BRAF, and microsatellite instability status was lacking for much of the study period. Even so, because the cohort included elderly patients with common comorbidities, it reflects a population closer to real-world practice than the highly selected patients enrolled in clinical trials. The authors conclude that postoperative LMR and CAR are promising predictors of adjuvant chemotherapy efficacy in this growing patient population and hope the work will spur development of novel biomarkers for guiding treatment decisions in elderly cancer care.

Subject of Research: Predicting adjuvant chemotherapy efficacy in elderly stage III colorectal cancer patients using immuno-nutritional and inflammatory blood markers

Article Title: Predicting the Efficacy of Adjuvant Chemotherapy Using Immuno‐Nutritional and Inflammatory Markers in Elderly Patients With Stage III Colorectal Cancer

Article References: Tago, T., Takamizawa, Y., Kato, T., Nagata, H., Moritani, K., Tsukamoto, S., & Kanemitsu, Y. (2026). Predicting the Efficacy of Adjuvant Chemotherapy Using Immuno‐Nutritional and Inflammatory Markers in Elderly Patients With Stage III Colorectal Cancer. Annals of Gastroenterological Surgery, 10(5), 1575-1585. https://doi.org/10.1002/ags3.70235

Image Credits: AI Generated

DOI: 10.1002/ags3.70235

Keywords: colorectal cancer, adjuvant chemotherapy, elderly patients, lymphocyte-to-monocyte ratio, C-reactive protein-to-albumin ratio, immuno-nutritional markers, inflammatory markers, propensity score matching, recurrence-free survival, biomarkers, National Cancer Center Hospital, Annals of Gastroenterological Surgery