[Mtngrl]

Here's what one of the reports says about the two competing theories about resecting the original tumor. On the one hand, it might exacerbate the mets (although they might then be easy to eliminate with chemo because they're growing so fast). On the other hand, the main tumor might have an overall immune-suppressing effect that goes away if it's removed.

Other theories have been proposed regarding the effect of surgical removal of the primary tumor on the growth kinetics of micrometastases. Retsky et al. found that surgical removal of the primary tumor accelerated relapse in premenopausal node-positive patients, which may have resulted from the removal of angiogenic inhibitors with resection of the primary tumor. In contrast, others have shown that a surge of angiogenesis in distant metastatic disease sites may allow for a highly chemosensitive state in the rapidly growing metastases and account for the prolonged survival seen in patients with metastatic cancers who underwent adjuvant chemotherapy soon after surgery.

Another theory focuses on the primary tumor's modulation of the immune system. Danna et al. demonstrated that a primary tumor may influence metastatic disease progression through the release of immunosuppressive factors. The restoration of immunocompetence after removal of the primary tumor may be due to a quantitative decrease in the production of immunosuppressive cytokines or due to a qualitatively less efficient immunosuppressive cytokine production by metastatic colonies. Nonetheless, removal of the primary tumor seems to restore immune competence by removing a potentially dependent relationship between the primary tumor and its metastases.