[Cancer] Adding herbal medicine to capecitabine chemotherapy for colorectal cancer: higher tumor response, fewer side effects — a paper review from Sandol Korean Medicine (Sejong)

"While I'm on chemotherapy, is it better to take herbal medicine, or to hold off for a while?" This is the question colorectal cancer (CRC) patients facing chemotherapy ask most often. The short answer is that, according to recent evidence, adding herbal-medicine treatment to standard chemotherapy raises the treatment effect and lowers side effects. Let's look at the actual evidence.

39 randomized controlled trials, 1,384 patients gathered in one place

Published in 2023 in the international journal Cancer Medicine, this study is a meta-analysis that systematically gathered only randomized controlled trials (RCTs) in which herbal medicine was added to capecitabine-based regimens — capecitabine being an oral chemotherapy drug widely used in colorectal cancer. Searching eight databases including the Cochrane Library, PubMed, and Embase for studies up to March 2021, it ultimately pooled data from 39 clinical trials totaling 1,384 patients. Rather than testimonials from individual hospitals, it drew the big picture only from trials that reduced bias through randomization.

Through the Sandol Korean Medicine blog and website columns, we have been introducing a range of herbal cancer-care studies covering gastric, liver, colorectal, lung, breast, pancreatic, and other cancers. What we confirm again and again is that individual studies from different countries, different cancer types, and different research teams arrive, as if by agreement, at the same conclusion. They slow the onset of cancer (a preventive effect), lower mortality, raise survival and quality of life, and reduce the side effects that inevitably accompany standard treatment. This colorectal cancer study traces the same trajectory within that larger picture.

Tumor response went up, and quality of life rose sharply

First, the effect. Compared with the capecitabine-only group, the group that added herbal medicine had a higher rate of actual tumor shrinkage — that is, the objective response rate (ORR) was 35% higher (relative risk RR 1.35, 95% confidence interval 1.17–1.55, heterogeneity I²=0%). The disease control rate (DCR) — the proportion whose tumors were kept from growing further — was 22% higher (RR 1.22, 1.12–1.32), and the proportion of patients whose quality of life (QOL, by Karnofsky performance status) improved was a striking 71% higher (RR 1.71, 1.44–2.03). The 1-year survival rate was likewise 18% higher (RR 1.18, 1.04–1.35).

Every figure points the same way. The conclusion is that taking herbal medicine is decidedly beneficial. Even when the same chemotherapy drug was used, patients who added herbal medicine had their tumors shrink better and were able to spend their time in treatment in a more humane way.

Side effects were cut by 20–40% — the real story is here

In fact, the more striking part of this study is the side effects. Capecitabine carries burdens such as diarrhea, tingling in the hands and feet, and myelosuppression, but when herbal medicine was added, most of the toxicities decreased significantly. Diarrhea fell by 39% (RR 0.61, 0.49–0.74), liver and renal function abnormalities by 36% (RR 0.64), and myelosuppression, neutropenia, nausea and vomiting each by 33% (RR 0.67), anemia by 31% (RR 0.69), leukopenia by 30% (RR 0.70), thrombocytopenia by 24% (RR 0.76), and neurotoxicity by 21% (RR 0.79).

On top of this, the herbal medicine combination group saw their T-lymphocytes — central to immunity — improve as well. In particular, helper T cells (CD4+) and the CD4+/CD8+ ratio improved significantly (CD4+ RR 1.70, 1.27–2.13). In effect, herbal medicine both suppressed side effects so that treatment could be carried through to the end and preserved the body's baseline capacity to fight the tumor.

Which medicines worked — the power of tonics

The researchers performed a sensitivity analysis to see which herbs contributed to these results, and among formulas traditionally classed as tonics, the qi-tonifying (Bu Qi) formulas that replenish energy played an important role.

What is notable is that these medicines are not drugs that directly "attack" the tumor. Rather than targeting the cancer itself, Korean medicine protects the "soil" — digestion, energy, and immunity — that is easily eroded by chemotherapy. Just as crops survive only when the field holds up, the patient's strength must hold up for standard treatment to be completed at the planned dose and schedule, and that completion ultimately leads to response and survival. Reducing side effects so that treatment is not discontinued — this is the most important effect of all, even if it is hard to see.

In closing

This study, too, reaches the same conclusion as those introduced earlier. Combining herbal-medicine treatment with standard treatment is beneficial in many ways.

If you are undergoing cancer treatment or are about to begin, we close by encouraging you to discuss combining herbal medicine with a Korean-medicine specialist experienced in integrative cancer care.