Yes. Surgery is the only curative treatment for colorectal cancer.  Chemotherapy and radiotherapy are used together with surgery, either before (neoadjuvant) or after (adjuvant) the surgery to further increase the rate of overall and/or disease-free survival. 

In your wife’s case, chemotherapy and RT is used before surgery, as a form of neoadjuvant treatment, with the intention of decreasing the chance of local recurrence which means to decrease the chance of the cancer coming back at the same place. Occasionally, repeat imaging after chemo- and radiotherapy shows a marked improvement of the tumour size. However, even an apparent complete resolution of the tumour does not equate to a pathological complete response as microscopic tumour cells would still be present. 

This means that in 35 percent of patients receiving neoadjuvant chemotherapy and radiotherapy, no residual tumour is seen on imaging but 65 percent of these patients will still have tumour present microscopically when surgery is performed and the specimen is taken for analysis.  As such, your wife would still need to undergo surgery on top of the chemo- and radiation therapy as surgery would remove the entire tumour and is the only curative modality of colorectal cancer. 

Many forms of alternative therapy are associated with minimal or no risk.  However, there is no compelling evidence that alternative medicine will help to enhance the quality of life or improve the overall survival of a patient. In addition, there are potential toxicities, both direct and indirect, that are related to such therapy. 

Firstly, a variety of herbal medications may produce direct side effects such as diarrhea, headache, hypertension, insomnia, nausea and in more severe cases, renal failure.  Such alternative therapy may also interact with chemotherapeutic agents and hence should not be used during the course of chemotherapy. Such alternative therapy should also be avoided before surgery as its effect on immunity, bleeding or coagulopathy remain largely unknown.