Risk of unplanned visits for colorectal cancer outpatients receiving chemotherapy: a case-crossover study

This study was conducted to evaluate the impact of chemotherapy on the risk of unplanned visit in a cohort of colorectal cancer outpatients. Chief complaints for unplanned visits and risk factors for hospital admission were also analyzed.

Clinical data of 229 consecutive colorectal cancer patients who were unexpectedly presented to our acute oncology clinic between 2006 and 2009 were reviewed. A case-crossover statistical analysis was applied to study the association between exposure to chemotherapy (trigger event) and the occurrence of unplanned visit (acute outcome) in three time windows (7, 15, and 21 days from the closest previous chemotherapy treatment). Cox model was used to assess the risk factors for hospitalization.

There were 469 unplanned visits registered. Most of the patients had Eastern Cooperative Oncology Group performance status (ECOG PS) 0-1 (80 %) and advanced cancer stage (78 %). The majority of unplanned visits (72 %) occurred within 30 days since last chemotherapy. The most frequent presenting complaints were pain, fatigue, and anorexia. The two time windows associated with higher risk of visit were 15 and 21 days from last treatment, both for early (odds ratio [OR] 3.8, CI 1.4-10.2 and OR 3.8, CI 1.4-10.2) and advanced disease stage (OR 1.71, CI 1-2.9 and OR 3, CI 1.5-5.9). Of the unplanned visits, 10 % resulted in hospital admission. Presenting with multiple symptoms and with deteriorated PS were both predictors for hospitalization.

Chemotherapy exposition triggers the need for unplanned visits over the second and third week after treatment. The prompt and effective management of unexpected events may be cost- and time-saving and reduce pressure on oncology services.