No, chemo is not 'deadlier than cancer.' The whole point of chemo is to treat the cancer. (Which depending on type of cancer and stage, might mean a cure [even stage 4 cancer is curable if you are talking about some types of lymphoma] or a remission, or gaining the patient more time.
But chemo is tough, and for a few patients (especially if they are elderly or frail or have underlying conditions] the side effects of the chemo may be too much. All patients ARE, of course, informed and advised on the risks and benefits, and make an educated decision about whether the proceed with treatment.