When you say "community nursing" can you be more specific? Where I work we have a support program for women with breast cancer - it offers lymphedema evaluation and prevention protocols. You could do something related to those that utilize a prevention program for lymphedema (or other side effect of cancer treatment) vs. those that do not? Or something related to family support for those with a new dx of cancer?
why not find out about diet of patients undergoing radiotherapy or something relevant to public health nursing which is necessary to reach out to these patients.