Colorectal cancer

Positive results have been obtained from randomised controlled single or multicentre trials in patients with advanced colorectal cancer including those with stage II/III diseases9, 17-20. A summary of results from randomised controlled trials for both disease response and survival outcome in patients with colorectal or colon cancer receiving chemotherapy or radiation therapy with PSK is shown in (Table 1). The results showed that PSK immunotherapy significantly improved overall survival and disease-free survival rates. For example, as shown by the survival curves (Figs. 1A and 1B), patients with Stage II/III or Stage III colorectal cancer significantly benefited from PSK immunotherapy following surgery18.

Table 1. Selected Randomised Controlled Trials for Colorectal Cancer

955 cases
56 controls
1. Surgery + placebo
2. Surgery + PSK
(3gm/day for 2 months;
2g/day for 24 months;
1 gm/day thereafter)
8-yrs survival rate significant in the PSK group( p<0.05);
Disease-free interval

221 cases
227 controls
2.Chemo+ PSK
(3g/day for 3 years)
Disease-free interval and survival
significantly better for PSK in the colon group (p<0.05 in both)
18Total 207
134 cases
67 controls
6 withdrew
1. Chemo
2.Chemo+ PSK (3g per day for >2 yrs)
Overall survival rate higher in the PSK group but not significant (p=0.21).
3-year disease-free survival rate
significantly higher in the PSK group
Stage III. Patients 3-year overall and disease-free survival rates in the PSK significant (p=0.02; p =0.01)
19Total 205
137 cases
68 controls
All patients received
Mitomycin-C post-surgery.
1. Chemo
2. Chemo + PSK (3g/ day)
Both treatments for 2 yrs
5-year disease-free survival and
5-year overall survival rate
significantly higher in the PSK group
(p<0.016, p <0.056 respectively).

Stage III patients: Overall and
5-year disease-free survival in PSK group (p <0.003; p<0.002).
20Colon cancer
with lymph

Total 441
220 cases
221 controls
All patients received
chemo after surgery
for 3-4 weeks, then
10 courses of treatment.
1. PSK 4 weeks then 4weeks
2. 4 weeks rest then 4 weeks
Seven- year survival rate
Significantly higher in the PSK group (p=0.019).
Overall survival or disease-free
rates not significant.

Fig 1AFig 1B

A meta-analysis has been performed to evaluate the combined data from three centrally randomised clinical trials for a comparison of the effect of adjuvant immunotherapy using PSK and chemotherapy (n=578) with that of chemotherapy alone (n=516) for 1,094 patients with curatively resected colorectal cancer21. All trials had a follow-up for 5-years after surgery and the end-points were overall survival and disease-free survival (Figs. 2A and 2B). The overall survival risk ratio was 0.71 (95% CI: 0.55-0.95, p <0.006) and the disease-free survival risk ratio was 0.72 (95% CI:58-0.90; p <0.003)21.  The results demonstrated that adjuvant immunotherapy with PSK is effective with respect to improved survival and disease-free survival of patients with curatively resected colorectal cancer.

fig 2afig 2b