PSK has also been shown to be effective in adjuvant therapy for breast cancer (Table 4). The trials showed a trend towards an improvement in patients treated with chemotherapy plus PSK than those treated with chemotherapy alone although the differences were short of significance(p=0.099)56,57.
Overall disease survival was also better in the chemotherapy plus PSK group but it also did not reach significance (p=0.0739). However, when the patients were stratified according to HLA-B40 antigen, the results showed that patients positive for HLA-B40 had a better survival rate than patients who were HLA-B40 negative (100% (9/9) vs 55% (7/13), p <0.05) at 5 yrs.58 It was concluded that HLA-B40-positive patients may benefit most from adjuvant immunotherapy with PSK.
Table 4. Randomised controlled trials for breast cancer
Standard or Radical mastectomy
|11A, 11B, 111||1. Patients (ER + tumours)|
chemo + / - tamoxifen
2 patients (ER – tumour)
Chemo + / - PSK
|Longer overall survival for patients in Stage 11A T2N1 cancer ER and node-negative treated with chemo + PSK compared with other ER subgroups without PSK|
|57||227 cases operable breast cancer with v+ and/or n+ involvement||Chemo (n=77)|
Chemo +LMS (n=76)
Chemo + PSK (n=74)
|Risk ratio lower in the chemo+ PSK group. Overall and disease-free survival rates not significant for all groups.
** See later published analysis of the HLA-status of these Patients below (ref 58)
Typed as HLA-A, HLA-B and HLA-C
|Operable with v+ and/or nv+||Previously randomised into two groups (ref 54)|
2. Chemo +PSK
each group stratified by HLA type B40+ or B40-
|Disease-free survival at 4 and 10 years for chemo + PSK group.
HLA-B40+ : 100%
HLA-B40- : 76% and 55% respectively. Significant difference at p=0.05