Resected colorectal cancer among Medicare beneficiaries:adoption of FDG PET

Reliability of Contrast CT and Positron Emission Tomography in Post-Surgical Colorectal Cancer and Its Association with Obesity

BACKGROUND

Post-surgical recurrence of cancer colon occurs in one-third of patients within the first two years, so early detection is important. The assessment of the therapeutic response is important to change protocol strategy. Positron emission tomography/computed tomography PET/CT, a valuable tool gives both metabolic and anatomic information for whole-body regions. Obesity is an important risk factor for colorectal cancer.

AIM

To evaluate post-surgical and therapeutic colorectal cancer by PET/CT and study obesity association to its prognosis.

METHODS

This was a prospective study involved 93 patients with, post-surgical colorectal cancer examined by PET/CT, then follow up after 4-6 months.

RESULTS

There was a statistically significant difference between PET/CT and contrast CT. The sensitivity& the specificity were (96.4%-100% & 92.3%-98.2%) for PET/CT and (84.2%-90.2% & 76.5%-85.4%) for contrast CT respectively. Post-therapeutic follow up showed; progressive course (24.5%), stationary course (26.4%), partial regression (28.3%) and complete regression course (20.8%). Obesity is a risk factor for progression with highly statistically significant to treatment response. Obese patients had a progressive or stationary course of the disease. Also, there was a highly statistically significant association between total abdominal fat & visceral abdominal fat areas with good response of treatment.

CONCLUSION

PET/CT is the most appropriate imaging technique to detect any recurrence or metastases in post-surgical colorectal cancer with high sensitivity and specificity comparing to CT. Obesity is a predictor risk factor for prognosis of the disease, as generally and abdominally (total & visceral fat) had an association with therapeutic response.

Trends in the Use of (18)F-Fluorodeoxyglucose PET Imaging in Surveillance of Non-Small-Cell Lung and Colorectal Cancer

PURPOSE

Surveillance PET after curative-intent treatment of non-small-cell lung cancer (NSCLC) or colorectal cancer (CRC) is not clearly supported by available evidence or the Choosing Wisely campaign. However, the frequency of PET imaging during the surveillance period is relatively unknown.

METHODS

Using Surveillance, Epidemiology, and End Results-Medicare data, 65,748 patients aged 66 years or older who were diagnosed with stage I to IIIA NSCLC or stage I to III CRC from 2001 through 2009 and who underwent surgical resection were identified. Trends in "any PET" or "PET-only" use 6 to 18 months postoperatively were assessed.

RESULTS

Any PET use more than doubled over the study period. Eleven percent of patients with NSCLC and 4% of those with CRC diagnosed in 2001 received any PET, compared with 25% of patients with NSCLC and 13% of those with CRC in 2009 (P < .001 for both). Higher stage disease was correlated with higher PET utilization and faster growth in use over the study period. PET-only use also increased over the study period, especially in higher stage disease. Fewer than 2% of patients diagnosed with stage IIIA NSCLC in 2001 received PET only, compared with 15% of patients diagnosed in 2009 (P = .014). Similarly, 1% of patients diagnosed with stage III CRC in 2001 received PET only, compared with 8% of patients diagnosed in 2009 (P < .001).

CONCLUSIONS

PET utilization during the surveillance period increased between 2001 and 2009. Further research is needed to determine the factors driving use of surveillance PET and to examine relationships between PET and patient outcomes.

Variation in positron emission tomography use after colon cancer resection

PURPOSE

Colon cancer surveillance guidelines do not routinely include positron emission tomography (PET) imaging; however, its use after surgical resection has been increasing. We evaluated the secular patterns of PET use after surgical resection of colon cancer among elderly patients and identified factors associated with its increasing use.

PATIENTS AND METHODS

We used the SEER-linked Medicare database (July 2001 through December 2009) to establish a retrospective cohort of patients age ≥ 66 years who had undergone surgical resection for colon cancer. Postoperative PET use was assessed with the test for trends. Patient, tumor, and treatment characteristics were analyzed using univariable and multivariable logistic regression analyses.

RESULTS

Of the 39,221 patients with colon cancer, 6,326 (16.1%) had undergone a PET scan within 2 years after surgery. The use rate steadily increased over time. The majority of PET scans had been performed within 2 months after surgery. Among patients who had undergone a PET scan, 3,644 (57.6%) had also undergone preoperative imaging, and 1,977 (54.3%) of these patients had undergone reimaging with PET within 2 months after surgery. Marriage, year of diagnosis, tumor stage, preoperative imaging, postoperative visit to a medical oncologist, and adjuvant chemotherapy were significantly associated with increased PET use.

CONCLUSION

PET use after colon cancer resection is steadily increasing, and further study is needed to understand the clinical value and effectiveness of PET scans and the reasons for this departure from guideline-concordant care.

Associations between cancer-related information seeking and receiving PET imaging for routine cancer surveillance--an analysis of longitudinal survey data

BACKGROUND

Routine cancer surveillance with positron emission tomography (PET) is not recommended for most patients who have completed curative treatment for cancer. Yet, recent trends suggest that PET is increasingly used for follow-up among patients with cancer. This study investigates whether information-seeking behaviors predicted self-reported utilization of PET for routine surveillance in patients with colorectal, breast, and prostate cancer.

METHODS

We conducted annual surveys for 3 years in a cohort of Pennsylvania cancer survivors diagnosed with colorectal, breast, or prostate cancer in 2005. The outcome was self-reported PET receipt for routine surveillance among 944 patients diagnosed with nonmetastatic disease (stages 0-III). Predictors included cancer-related information seeking from nonmedical sources and providers. Weighted multiple logistic regression analyses were performed.

RESULTS

In this population, 11% of patients reported receiving at least one PET scan for routine follow-up in a 12-month period several years after diagnosis. Seeking cancer-related information from nonmedical sources was associated with higher odds of subsequent reported PET use [OR, 3.7; 95% confidence interval (CI), 1.1-12.1; P = 0.032], after adjusting for potential confounders. Patient engagement with physicians about cancer-related information was not a significant predictor.

CONCLUSIONS

Overall reported PET utilization for routine surveillance of colorectal, breast, and prostate cancer is low. However, we found a significant association with information seeking from nonmedical sources but not from providers.

IMPACT

Exposure to cancer-related information through mass media and lay interpersonal sources may be driving inappropriate utilization of high-cost advanced imaging procedures. These findings have important implications for cancer survivors, healthcare providers, and health policy.

Predictors of initial 18F-fluorodeoxyglucose-positron emission tomography indication among patients with colorectal cancer

OBJECTIVES

To evaluate the determinants of initial F-fluorodeoxyglucose (F-FDG)-PET indication following primary colorectal cancer diagnosis among patients who underwent surgery between January 2000 and December 2007 and who were observed at a single institution for at least 2 years after diagnosis.

METHODS

Of the 530 patients who underwent colorectal cancer resection, 113 patients received at least one F-FDG-PET following diagnosis. Outcome variables included indication and time of the first F-FDG-PET following diagnosis. Potential predictors included disease-level and patient-level characteristics. Univariate and multivariate regression analyses were performed.

RESULTS

Patients diagnosed later in the study period and patients with higher-stage disease were more likely to receive their first F-FDG-PET for initial staging (P<0.001 and P=0.016, respectively). Patients with lower-stage disease were more likely to receive their initial F-FDG-PET for suspected recurrence on conventional imaging. When performed more than 2 years after diagnosis, F-FDG-PET was more likely to be ordered for suspected recurrence either on the basis of conventional imaging or on the basis of patient symptoms/tumor markers (P=0.003 and 0.031, respectively). F-FDG-PET demonstrated disease progression in at least 50% of patients referred for each indication (P=0.037).

CONCLUSION

Higher utilization of F-FDG-PET may be appropriate among patients referred for a number of indications including: initial staging, particularly among those with higher-stage disease; suspected recurrence on conventional imaging among patients with lower-stage disease; and suspected recurrence more than 2 years after diagnosis. Further research is needed to verify these findings.