Short- and Long-Term Side Effects from Adjuvant and Neoadjuvant Treatment of Rectal Cancer

Adjuvant therapy in rectal cancer patients involves most often chemotherapy or in rare cases radiotherapy after the tumour has been removed surgically without any signs of remnant macroscopic or microscopic disease. Neoadjuvant treatment means radiotherapy, chemotherapy, or chemoradiation before the tumour has been removed surgically. As chemotherapy inhibits and kills cancer cells as well as normal cells, some side effects are often unavoidable. Ideally benefits and side effects should be balanced, but at present, it is not possible to individualise the treatment with respect to differences in pharmacodynamics and pharmacokinetics. Not only the frequency but also the severity of the side effects must be evaluated, and scoring systems like the Common Toxicity Criteria can be used. Nausea and vomiting may be prevented to some extent by various measures. Both early and late side effects of radiotherapy are dependent on irradiated volume, total dose, fractionation, and total time for treatment. Early toxicity is more frequent after chemoradiation than after radiotherapy alone. Ageing involves a reduction of physiologic reserves, absorption, metabolism, and elimination which may be associated with increased toxicity. However, performance status and functional status should be more important than age alone for recommending adjuvant or neoadjuvant therapy.