The effects of Vitamin C on neighbouring non-tumor cells and their tumor related secretions are now emerging. I feel blessed that I personally combined high dose Vitamin C with my first line treatments. (a keto-diet, radiation to the spine and oestrogen blocking -my cancer was diagnosed as an ER+ type).

Vitamin C targets the metastatic tumor microenvironment (TME)

“Many studies have focused on the role of Vit C in targeting tumor cells in isolation. As the effects on neighbouring non-tumor cells and their secretions emerge, studies on the mechanisms underlying the specialised tumor microenvironment contribute to a deeper understanding of the impact of Vit C in the complex microenvironment” It has been proven that Vitamin C can inhibit the degradation and remodelling of the extra cellular matrix (ECM) and can prevent bone metastasis of cancer cells..”
www.sciencedirect.com/science/article/pii/S0753332220307812

“During bone metastases, cellular compounds produced by the primary tumor enter the bloodstream and act at distant sites, stimulating angiogenesis and infiltration of Tregs, MDSCs, and other immune cells to generate a pre-metastatic niche. The colonised tumor cells then continuously interact with micro-environments to promote skeletal remodelling and immunosuppression, culminating in overt bone metastases.”
www.nature.com/articles/s41571-021-00499-9

Hypoxia and ECM remodelling are engaged in the metastatic process. By epigenetic mechanisms, Vitamin C significantly improves bone metabolism and bone formation. Vit C modulates stromal cell differentiation, promoting osteoblast development while suppressing osteoclasts, possibly alleviating tumor-induced aggressive osteolysis.
www.mdpi.com/2072-6643/11/3/506

The synthesis of type I collagen is enhanced by Vitamin C, which not only improves the stability of the bone matrix but also contributes to osteoblasts differentiation
journals.plos.org/plosone/article?id=10.1371/journal.pone.0220653.

Higher doses of Vit C (100 μM) alter miRNA expression to up- or down-regulate signalling pathways associated with cell adhesion, differentiation, and cell steaminess in BMSCs.
www.mdpi.com/2072-6643/10/2/186

RANKL/NFκB in osteoclasts is an essential signalling pathway that accelerates bone metastasis. A Vit C deficiency status up-regulates RANK expression in vitro and in vivo, suggesting a negative regulation of RANK. These findings indicate that Vit C may inhibit tumor growth by acting on metastases, as well as the main location.
www.sciencedirect.com/science/article/abs/pii/S0955286310000355

The existing research on the effects of Vitamin C on the bone microenvironment focuses mostly on preventing osteolysis and bone loss. Further research into this function for certain osteogenic metastases is warranted. Vitamin C may help patients with advanced cancers avoid complications like osteoporosis and fractures by acting as a supportive treatment. www.mdpi.com/2072-6694/14/11/2608.

My high-dose Vitamin C recipe is here.

"Since my diagnosis of bone mets in 2017 I have been making and taking loads of Liposomal Vitamin C. My cancer damaged bones just soaked it up in huge quantities the first couple of years of my healing. You too, may very soon be making your own Vitamin C, as it's not cheap to buy and often comes with extras we don't need. And as you are coming to learn, it is so beneficial to healing and preventing cancer from returning and metastasising."