Introduction
Writing in 2006 and leveraging a background as an oncology nursing practitioner and professor attached to a Department of Physiological Nursing, Viale assembled critical updates on adjuvant therapies to manage the long-term remission of colon cancer. Colon cancer remains the third most prevalent for both genders in both Europe and the U.S.A. and causes around 200,000 deaths annually.
At the time of writing, however, survival rates had improved markedly owing to better knowledge about pathogenesis, more widespread screening, and what seems a more effective repertoire of adjuvant chemo- and biological therapy.
Three Key Points
Opting to focus on areas of adjuvant therapy that Viale covers, the three critical themes in the article consist of: a) Oxaliplatin showing promise in raising the odds of long-term survival; b) nurses needing to be attentive to the toxicities involved; and, c) biologic agents also had a role to play in adjuvant therapy.
Post-surgical resection, adjuvant therapy had traditionally been concerned with forestalling any micro-metastasis. The old standbys were radiation and chemotherapy, the latter relying on 5-fluorouracil (5-FU). Within the last decade, it was discovered that the combination of 5-FU and leucovorin worked well even for stage II and III metastatic colon cancer. Adjuvant therapy took another step forward in 2003 when it was discovered that adding oxaliplatin to 5-FU and leucovorin improved survival measurably for stage III patients. Hence, current National Comprehensive Cancer Network (NCCN) guidelines for stage III colon cancer calls for administration of 5-FU, leucovorin, and oxaliplatin (or capecitabine to replace the last).
Distinct from the mucositis, hand-foot syndrome, and diarrhea that are the toxicities to be expected with 5-FU and leucovorin or capecitabine, oxaliplatin is more likely to induce such side-effects as neurotoxicity, nausea, and hypersensitivity. Neurotoxicity or peripheral neuropathy is especially likely to occur after multiple cycles. Though not strictly classed as a vesicant, oxaliplatin can also trigger tissue necrosis. Both venlafaxine and calcium-magnesium seem helpful in mitigating neurotoxicity. Keeping patients warm also helps. In any case, the majority of patients seem to leave neurotoxicity behind when the course of treatment with oxaliplatin is complete.
Beginning in 2004, two biologic agents received approval for adjuvant therapy in colon cancer. These are cetuximab and bevacizumab, both monoclonal antibodies. The former promotes antiangiogenesis with an affinity for the epidermal growth factor receptor. cetuximab mitigates malignant cell proliferation by damping down signaling from the growth factor. In turn, bevacizumab acts on the vascular endothelial growth factor; targeting VEGF and effectively reducing blood supply to the tumor. The official FDA stance is for fortnightly administration of bevacizumab for first-line treatment, given every two weeks in combination with chemotherapy treatment involving 5-FU. The approved use of cetuximab, singly or together with irinotecan, is as a second-line treatment for metastatic cancer of the colon.
Benefit and Practical Application to Nursing
Oncology nurses can exude a more optimistic bedside and post-operative manner given the availability of FDA-approved oxaliplatin, capecitabine, and irinotecan for adjuvant therapy. Such knowledge is critical because the odds are greater than 50% that colon cancer patients who have been operated on and no longer show macroscopic signs of the disease still succumb to a recurrence or a remote metastasis. Moreover, well-informed oncology practitioners are in an excellent position to offer reassurance about the increasingly wider range of beneficial agents, the toxicities trade-off to which increasingly-older colon cancer patients are especially sensitive, and to give vigilant care when prolonged infusion seems appropriate for the individual. Certainly, nurses can make a difference in improving survival rates for stage III and IV patients by remaining up to date about treatment options offered by new adjuvant agents and being frank about the improved odds of surviving provided treatment is initiated in short order. Such roles are especially important when patients put a higher priority on survival and are willing to tolerate adverse side-effects or low to moderate toxicity.
References
Viale, P. (2006). Expanded treatment options in the adjuvant therapy of colon cancer: Implications for Oncology nurses. Oncology Nursing Forum, 33 (1): 81-90.