___________________________________________________________________________ Colorectal Cancer
Oxaliplatin-Associated Hepatotoxicity Elevations in serum liver enzymes are common during treatment with oxaliplatin. Oxaliplatin-induced sinusoidal obstruction syndrome (SOS) (formerly known as hepatic veno-occlusive disease) has become a key concern for patients receiving the agent for colorectal cancer [345]. Chemotherapy-Associated Gastrointestinal Toxicity Diarrhea, nausea, vomiting, and/or abdominal pain com- monly occur with chemotherapeutic agents. Management is symptomatic, with loperamide for diarrhea, antiemetics for nausea and vomiting, and analgesia for pain [174]. Chemotherapy-Associated Alopecia Alopecia is a short-term adverse effect of certain chemothera- pies. This effect will resolve with cessation of treatment, but in the interim, management is largely cosmetic. Cetuximab-Associated Rash Acneiform rash is very common in patients being treated with cetuximab. It primarily occurs on the face and upper torso, often improves with continued treatment, and is reversible. This complication is associated with improved chance of treat- ment response independent of KRAS status [174]. Radiation Therapy-Associated Fecal Incontinence Loose stool, urgency, and fecal incontinence are common after radiation therapy for rectal cancer [174]. Patients should be prepared for this long-term complication. Bladder Dysfunction after Rectal Excision Bladder dysfunction can result from damage to the pelvic nerves during rectal cancer surgery. Symptoms can include urinary urgency, incontinence, and retention. Urinary cath- eterization may be required to relieve retention [174]. Erectile Dysfunction after Rectal Excision Erectile dysfunction can also occur due to pelvic nerve dam- age. In one study of 28 men treated for colorectal cancer, 24 reported experiencing erectile dysfunction after treatment (i.e., chemotherapy, radiation, and/or surgery) [346]. Almost none of the men in the study received adequate care and education related to this complication. Oxaliplatin-Associated Pulmonary Fibrosis Pulmonary fibrosis occurs in less than 1% of patients being treated for colorectal cancer [174]. This generally presents as dry cough, dyspnea, basal crepitations, and pulmonary infil- trates on chest x-ray or CT. Oxaliplatin-Associated Neuropathy Neurotoxicity is a common adverse effect of oxaliplatin, usu- ally presenting as acute or chronic peripheral neuropathy. The acute form develops in more than 90% of patients, with usual onset during or shortly after the first few infusions.
Symptoms include paresthesias and dysesthesias in the hands, feet, and perioral region, and may be exacerbated by cold. It is self-limiting [174]. The chronic form is a cumulative axonal sensory neuropathy and may be dose limiting. The neuropathy is reversible in most patients after halting treatment. No intervention has shown definitive prevention of neurotoxicity. Adverse Effects of Anti-EGFR Agents Anti-EGFR agents have a specific adverse effect profile primar- ily involving skin toxicities. Electrolyte abnormalities also occur with these agents, especially magnesium-wasting syndrome. Cetuximab is associated with an infusion reaction caused by the immunogenicity of the chimeric antibody. The most prominent adverse effects of anti-EGFR agents are skin lesions (e.g., acneiform eruption, paronychial inflammation) and hair abnormalities (including a marked increase in the length of eyelashes). These are sometimes dose-limiting complications that, while not fatal, can greatly interfere with patients’ quality of life. The development of skin toxicities (particularly more intense reactions) has actually been associated with better out- comes of cetuximab and panitumumab. Preliminary evidence shows benefit with use of a pre-emptive prophylactic skin treat- ment regimen of skin moisturizers, sunscreen, topical steroids, and doxycycline [237; 347]. The risk of high-grade skin toxicity tends to be elevated for patients in which treatment duration is longer [348]. POST-TREATMENT FOLLOW-UP After patients with colorectal cancer finish their treatment, they are often discharged from specialist care, with follow- up performed by community-based family physicians or institution-based, nurse-coordinated care. As there is a transfer of responsibilities, it is important to have guidelines for the follow-up of these patients. A treatment plan from the special- ist should be sent to the patient’s other providers, particularly primary care providers, and it should include clear directions on appropriate follow-up [349]. Postoperative surveillance of colorectal cancer is essential, and the objectives are to assess initial treatment efficacy, detect synchronous or metachronous malignancies, and identify potentially curable recurrent or metastatic cancers [350]. The benefits from routine, periodic assessments following colorectal cancer treatment include earlier identification and management of recurrent disease. Clinical trials have shown a significant survival advantage with more intensive follow-up protocols [350; 351]. Several guidelines for surveillance of patients following resec- tion of stage II/III colorectal cancer have been published. Due to minimal available and current data, few surveillance guidelines have been published for patients with stage I or resected metastatic disease [349].
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