spread to 1 lymph node

my 70 years old mom was diagnosed with bc , surgery , masectomy on both breast, cancer on 1 only, tumor 2cm , hormonal pos, clean margin, 6 nodes removed (only 1 with cancer).  grade 3 stage 2 , she have not seen her oncologist yet but surgeon said chemo for sure. She so scared and does not want chemo because of her age.
My question to you are :
With the 1 lymph node affected , does this means cancer has spread throughout the system and could be all over.
I have read that there are millions of tiny cancer cells within a tumor and when you cut it you risk spreading those cancer cells too, then why do some people don't need chemo when their lump is removed. what happen to those tiny cancer cell then why don't they need to be kill, why is the cancer in the lymph node more urgent.
It seems that neoadjuvent chemo does help shrink tumor alot, then why is it that it only helps a little bit with the small cancer cell after surgery. For my mom age group, 10years studies only increase her chances by 3-4%
Her surgeon told me that sometimes when he operate he can see the cancer is bad (but not the case with my mom), he only remove 6 lymph nodes (i've heard others has 10+ remove), does this means he already know hers is not bad and don't need to remove so much nodes??? (he cannot tell whether the lymph node is cancerous right? he made the number decision based on his instinct right?),does a big person has more node than others

I live far from my mom , so sitting down together with her oncologist is not possible, and she so much want my help in making her chemo decision

[CCF-RN,MSN-rf]

Dear vigilant:  In most cases, tumors can be removed without disruption so tiny cells spilling all over does not happen.  The concern when a lymph node is involved is that it indicates that cancer cells have already traveled outside the primary tumor.  The lymph nodes are the usual first site of metastasis since this represents that natural drainage system.  It does not mean that it has spread throughout the body but it does indicate that the possibility is higher.  We cannot compare neoadjuvant to adjuvant chemotherapy.  These techniques are used for separate situations that cannot be compared.  The number of lymph nodes removed is usually what is contained in the "fat pad."  This number varies from person to person.

[surgeon]

When cancer has spread to a lymph node, it raises the possibility that it could also be somewhere else. However, it's also possible that it has only spread there and no further. In fact, when only one node is involved the cure rate is nearly as good as when none are. In general when there has been any spread at all, it's recommended to use some form of chemotherapy, because it gets into the bloodstream and gets anywhere the tumor might be. However, in older women, often the best choice is hormone therapy, which has quite minimal side effects and has comparable results to the more toxic and difficult medications. I'd bet her oncologist will propose that to her, unless the tumor tests show it's not sensitive to hormone treatments. At her age the odds are very high that it will be, and that would be a good choice. If she were to choose no further treatment at all, she'd still have pretty good odds for long-term survival; they'd be increased some by treatment.

[vigilant]

thank you for your answers