Incidental detection on imaging performed during the work-up via MDTs of patients with kidney cancer – lucky find or poisoned chalice?
Incidental detection on imaging performed during the work-up via MDTs of patients with kidney cancer – lucky find or poisoned chalice?
Tan HW, Patel R, Hague AG, Staton CA, Bala SB
Incidental detection on imaging is a common problem. This problem is becoming more challenging with the ever-increasing amount of imaging that is being performed. Patients with cancer often undergo imaging, sometimes in several different modalities, to stage their disease and guide treatment. Incidental detection on imaging during cancer work up is a burden and has the potential to delay cancer treatment. The purpose of this study was to investigate incidental detection on imaging during kidney cancer work up and its potential to delay cancer treatment.
Patients with a new diagnosis of cancer over a 5-year period (2015-2019) in Sheffield Teaching Hospitals were identified from the cancer database. From this dataset, kidney cancers were identified. Scans of each patient at the time of their cancer diagnosis were identified and the reports of those scans were examined. Incidental detection was recorded. Incidental findings were defined using Young’s definition.
(Under materials and methods) Figure 1: Flow diagram of the methodology 555 patients were identified to have kidney cancers and amongst these, 358 patients had scans identified and 197 patients had no available imaging/no scans ordered.
(under results) Table 1: Summary of number of imaging performed and incidental findings found. The majority of patients underwent CT scan and an ultrasound. Certain patients had more than one scan of the same type but of different parts of the body due to various indications. Most incidental findings were found from CT scans and ultrasound.
(under results) Figure 2: Pie chart of categories of incidental findings. Most incidental findings were located in the urogenital, hepatobiliary and lung regions. Urogenital findings were mainly renal cysts and calculi. Hepatobiliary were mainly liver cysts, NAFLD and gallstones. Respiratory were mainly benign lung nodules, granuloma and emphysema.
A total of 555 patient were identified. 705 scans were performed. The majority were CT (67%). 347 scans had incidental detection, 63% of these were on CT. A total of 535 incidental detections were identified. 149 of these were urogenital, 139 were hepatobiliary, 85 were respiratory, 46 were gastrointestinal, 34 were MSK, 33 were endocrine, 20 were cardiovascular and 29 were under others. 533 of the 535 incidentalomas were benign. There were 2 new, unrelated malignancies identified. These included lung cancer and chronic lymphocytic leukaemia. After the incidental detection, there were 55 recommendations of additional imaging, endoscopies, biopsies, tumour markers and other blood tests. Median time from first MDT discussion to treatment was 35 days for patients with and without incidental detection. Time from first MDT discussion to treatment was 93 days and 197 days for patients who had isolated incidental lung cancer and chronic lymphocytic leukaemia respectively. There were examples of incidental detection of benign pathology that ultimately delayed cancer treatment. These included a colonic polyp on CT colonoscopy, pancreatic pseudocyst on CT and benign lung nodules on CT where the time from first MDT discussion to treatment was 440, 215 and 167 days respectively.
(under results) Figure 3: Flow diagram of incidental detection with recommendations made. After the initial 55 recommendations, only 37 patients had the recommendations acted upon. From these patients, additional tests were ordered and 35 patients had incidental findings proven to be benign and 2 proven to be malignant.
(under results) Table 2: Summary of additional tests ordered and incidental findings confirmed. Chronic lymphocytic leukaemia and squamous lung cancer were primarily identified from a CT scan after findings of a splenomegaly and a nodule in the right apex respectively. Further tests ordered were a full set of blood tests for malignancy screening and biopsy + histology for the malignancies respectively, which resulted in the diagnosis.
(under results) Table 3: Summary of median days and MDT discussions from 1st MDT meeting date to treatment of kidney cancer. 25 patients were excluded due to unavailability of treatment dates and 197 patients were excluded due to not having any imagings done. There was no difference in median time of MDT discussions and median days to treatment date for patients with and without incidental findings.
Incidental detection on imaging of patients with a new cancer diagnosis is a significant problem. The nature of vast majority of incidental detection is benign but can cause delay to cancer treatment. Common incidental findings include renal cysts, lung nodules, liver cysts and gallstones. 2 out of 555 patients had an isolated malignancy of lung cancer and chronic lymphocytic leukaemia found. Through this research, patients with incidental findings and no incidental findings were found to have no difference in their median number of MDT discussions (1) and median time to treatment (35 days).
