Should I continue my cancer treatment?

I've had a number of different cancers including addenocarcinoma of the colon,carcinomas of the tonsil with METS to a few lymph nodes. The adenocardinoma of the colom was treated with resection and has presented no futher problems. But unfortunately the tumor of soft palate metastasized to the lung which has always been treated with resection and chemo with a good result. It is now back in the soft palate with a recommendation for further radiation and chemo. At this point is there a point in pusuing treatment other than a desire to prolong life long enouh to see my granddaughter born in April? I already have a trach and a feeding tube. I realize this is very sketchy info and am not looking for a reasonable long term prognosis, just an opinion about continuing treatment on what appears to be a hopeless crusade.