The difference between Carcinosinum and carcinosinum-cum-cuprum is the more controlling state of this last remedy. It is only mentionned in Tinus Smits.

My feeling is that in carcinosinum you feel a strong sensitiveness and also story of familial or parental control and fastidiousness. In cuprum you may feel more about mineral or structure. The controling is more material. This is only feeling but i had two cases of Carcinosinum cum cuprum where i started with carcinosinum but after a time i had to go to cuprum (according repertory symptoms)... but cuprum helped for some time but did not stay longer time. Several times i had to switch and there was no other remedy coming in. So this two people need sometimes their carcinosinum cum cuprum. This was also the feeling of Tinus Smits when mixing this remedies.

(Tinus Smits limits his remedies to 9 in his inspiring homeopathy; personally i use sometimes his remedies and his way of thinking is very interesting but it is not totally my system of working)

In some cases carcinosinum helps as a turning-point remedy and helps people react or come up for their rights. There is a lot of suppression, coping with situations and not have the chance to react (chaotic, controlling, guilty feelings, some feeling of beïng incarcerated in situation). From Grandgeorges didier is coming the idea of keeping secret (you have not to tell this things...) and suppression of feelings. I can really confirm that this remedy , like he says, is a turning-point. It helps you to say 'NO' and react.

The fear of the use of carcinosinum is not substanciated.
Otherwise it can help us to find the connection to other so known Cancer-remedies (not in the way of producing cancer, but in the way of overcontrolling, guilty feelings, history of suppression).
In this view we must look for Cancer-miasm of Sankaran. (Ignatia, Staphysagria, Conium, Anacardium, Asarum...)


The question about the differential of Lac caninum and Carcinosinum is interesting because i have also the feeling that there is a strong connection but not in the direction of the source of the remedy (breastcancer and lactation). Both have strong suppression but the way of reacting is differential. Lac caninum will curs after reprimands and react strongly; Carcinosinum will suppress and hide themself .
Problem is that you need a feeling of the person in Carcinosinum and that repertorising will not give the result.