Agree w/ @gamaryanne completely. You need to know your mutations to determine eligibility and best fit for clinical trials. Two basic categories of mutations are germline (inherited from parents) and somatic (caused by environment or something other than inheritance).

I my case, I've been told the ATM mutation responds well to platinum agents. Although I didn't have a great response to the Folfirinox (which contains oxaliplatin) before Whipple, I've had a much better response (post-Whipple) to a cocktail which includes cisplatin.

After my recurrence, the local oncologist offered me Gem+Abrax w/o the cisplatin (he thought that would be too rough for me) or a clinical trial targeting ATM that didn't include cisplatin (and had 50% chance of containing placebo rather than the trial drug).

I'm now driving 2.5 hours each way for chemo (Gem+Abrax+cisplatin) that I'm responding very well to, while my care teams have time to look into newer trials more specific to ATM. There's a new maintenance therapy targeting BRCA1/2 and PALB2, which are similar to ATM, so drugs used on those might be my next option as well.

I look at genetic testing the same as any other data: It doesn't hurt anyone (at least not me) to know it, but it might hurt me to not know it.

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As far as delay in resuming chemo after a Whipple... hard to say. I had an open Whipple w/ 22 lymph nodes removed at age 59. I was pretty miserable (digestion and fatigue) for a solid month after surgery. It was 7 months post-op before I returned to work, mostly from home, on a slightly reduced schedule that allowed time for some naps.

Depending on what else I had going on (work and family responsibilities), I think I could have handled more chemo beginning 10-12 weeks after Whipple. That also depends on which chemo you're getting -- maybe more time if you're getting Folfirinox again, less time if you're getting something milder. If necessary to resume sooner, you could always ask the oncologists if they can ramp you up from a lower starting dose as you're able to tolerate it, or just omit certain drugs from the cocktail at first, then add them later as you are able to tolerate.