Methods for treating a human patient diagnosed with cancer with therapeutic neuromodulation and associated systems are disclosed herein. Sympathetic nerve activity can contribute to several cellular and physiological processes associated with the progression of cancer. One aspect of the present technology is directed to methods that attenuate neural traffic along target sympathetic nerves innervating tissue proximate a primary malignant tumor. Other aspects are directed to methods that at least partially inhibit sympathetic neural activity in a renal nerve of a patient diagnosed with cancer or who has a high risk of developing cancer. Targeted sympathetic nerve activity can be attenuated to improve a measurable physiological parameter corresponding to the progression of cancer in the patient. The attenuation can be achieved, for example, using an intravascularly positioned catheter carrying a therapeutic assembly, e.g., a therapeutic assembly configured to use electrically-induced, thermally-induced, and/or chemically-induced approaches to modulate the target sympathetic nerve.