Gamma linolenic acid with tamoxifen as primary therapy in breast cancer.
Gamma linolenic acid (GLA) has been proposed as a valuable new cancer therapy having selective anti-tumour properties with negligible systemic toxicity. Proposed mechanisms of action include modulation of steroid hormone receptors. We have investigated the effects of GLA with primary hormone therapy in an endocrine-sensitive cancer. Thirty-eight breast cancer patients (20 elderly Stage I-II, 14 locally advanced, 4 metastatic) took 8 capsules of oral GLA/day (total = 2.8 g) in addition to tamoxifen 20 mg od (T+GLA). Quality and duration of response were compared with matched controls receiving tamoxifen 20 mg od alone (n = 47). Serial tumour biopsies were taken to assess changes in oestrogen receptor (ER) and bcl-2 expression during treatment. GLA was well tolerated with no major side effects. T+GLA cases achieved a significantly faster clinical response (objective response vs. static disease) than tamoxifen controls, evident by 6 weeks on treatment (p = 0.010). There was significant reduction in ER expression in both treatment arms with T+GLA objective responders sustaining greater ER fall than tamoxifen counterparts (6-week biopsy p = 0.026; 6-month biopsy p = 0.019). We propose GLA as a useful adjunct to primary tamoxifen in endocrine-sensitive breast cancer. The effects of GLA on ER function and the apparent enhancement of tamoxifen-induced ER down-regulation by GLA require further investigation.
Kenny
F S
FS
Professorial Unit of Surgery, City Hospital, Nottingham, UK.
Pinder
S E
SE
Ellis
I O
IO
Gee
J M
JM
Nicholson
R I
RI
Bryce
R P
RP
Robertson
J F
JF
D000284:Administration, Oral; D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000009:adverse effects / Q000627:therapeutic use*; D001706:Biopsy; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D013629:Tamoxifen / Q000009:adverse effects / Q000627:therapeutic use*; D017965:gamma-Linolenic Acid / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*
D018931:Antineoplastic Agents, Hormonal; D019253:Proto-Oncogene Proteins c-bcl-2; D011960:Receptors, Estrogen; D013629:Tamoxifen; D017965:gamma-Linolenic Acid