Approach to the Solitary Pulmonary Nodule

1. Approach to the Solitary Pulmonary Nodule Hrach Ike Kasaryan

3. Definition SPN � is an intraparenchymal lung lesion that is < 3 cm in diameter and is NOT associated with atelectasis or adenopathy Lesions greater the 3 cm are defined as MASSES

10. Why is it concerning? SPN are concerning for what they could represent The absolute #1 concern is if the SPN is the harbinger of a malignancy What is more critical is the fact that the earlier you diagnose the malignancy the better the survival rate will be

11. Why is it concerning Chest. 1997 Jun;111(6):1486-7 Patients with the best prognosis are those found to have stage IA (T1N0M0) disease. These patients have a 61 to 75% 5-year survival following surgical resection Radiol Clin North Am 2000; 38:1�9 � Unfortunately they showed that almost 50% of patients have extrathoracic spread by the time of diagnosis these patients only had a 15% 5 year survival

12. Why is it concerning? With these numbers in mind, it is absolutely critical to give the SPN the attention it deserves If it is not worked up properly we will effectively push our patients who do carry a malignancy with in the SPN from the 75% survival into the 15% survival That is just unacceptable

13. Differential Diagnosis

16. Assessing Growth There are three categories to place the patient in assessing growth No change in two years / or Growth Rate of benign nature Indeterminate because of no old studies Growth Rate of possible malignancy

17. No change in two years Radiologic stability is the best predictor of a benign etiology. Since the 1950�s it has been well established that if the SPN has not grown in 2 years it is benign. (JAMA 1958; 166:210�215 ) If you have old radiographs and can show no change in two years, no further work up is needed

18. Benign vs. Malignant Doubling Time The time it takes for the apparent volume to double is referred to as the doubling time one doubling in volume is equivalent to the nodule diameter increasing by only 26% to 28% Benign nodules representing acute inflammatory changes have a doubling time of less than 20 days In contrast, stable granulomas and hamartomas may enlarge slowly and have a doubling time of more than 500 days

19. Benign vs. Malignant Doubling Time If the SPN has a doubling time of <20 days or >500 days the patient is in the clear and can be followed If however the SPN doubling time falls in between 20 and 500 days the SPN must be assumed malignant until proven otherwise and surgical intervention is now recommended.

20. Malignant Doubling Time With the numbers crunch, biopsy in this case is not worth the risks because a malignant diagnosis would not change resection therapy So in this case, surgical resection is highly recommended If the patient is reluctant or the risk of surgery is really high and you would like to be sure of diagnosis before going to the OR, than biopsy can be undertaken.

22. Indeterminate Growth Rate This is where the real dilemma is created and every radiological and clinical clue must be taken into consideration to make a decision. First step is to look at all patterns of the SPN and determine if a �typically benign or malignant pattern can be found�

23. Spiral CT with IV contrast Enhancement (SCTIE) SCTIE the imaging modality of choice for the SPN and should be obtained on all newly diagnosed SPNs A number of benign etiologies for SPNs have a characteristic appearance on CT

24. Fat Fat on CT can be diagnosed benign hamartoma with confidence

25. Solid or Central Calcification A solid calcified SPN is found in association with prior granulomatous infection, most commonly histoplasmosis or tuberculosis

26. Popcorn Calcification Popcorn calcification or Chondroid Calcification pattern typical of hamartomas

27. Speckled or Punctate Calcification Speckled or Punctate calcifications represent malignant calcification and should not be taken as benign

28. Eccentric Calcification Eccentric Calcification is also a sign of malignant potential

30. Radiological Findings If you have definitive findings suggestive of benign pattern than no further work up is needed. If still no answer after SCTIE or other radiologic finding further work up is needed

32. No Specific Pattern Found With no specific finding, all risk factors must be taken into account. Trying to milk the SPN for as much information you can may help stratify the risk in the patient

33. Size Size of the SPN can also help out at this point to help make a decision In general, smaller nodules are more likely to be benign and larger lesions 80% of benign SPNs are less than 2 cm in diameter However, small size is not necessarily reliable evidence of benignity because 15% of malignant nodules are less than 1 cm in diameter approximately 42% are less than 2 cm in diameter

34. Cavitation Although cavitation can occur in necrotic malignant SPNs, inflammatory lesions can also cavitate. The thickness of the cavity wall can be helpful in distinguishing benign from malignant lesions. Cavities with a greatest wall thickness less than 5 mm are almost always benign whereas most of those with a maximal wall thickness greater than 15 mm are malignant

35. Cavitation

36. Margins Smooth, well-defined margins most often indicate a benign nodule However 21% of malignant nodules have a smooth well-defined margin a lobulated margin may reflect uneven growth of a SPN and can indicate malignancy although 25% of benign nodules, particularly hamartomas, are lobulated

37. Indeterminate SPN After milking the SPN for all its characteristics it is now important to milk the patient for all relevant information Key points include: smoking history; symptoms; comorbid conditions (particularly severe emphysema); history and type of prior malignancy; prior infections and environmental exposures.

39. Odds Ratios Age 20-29 0.05 x 30-39 0.24 40-49 0.94 50-59 1.90 60-69 2.64 Nonsmoker 0.15 < 30 pk-yrs 0.74

41. Clinical Decision Now after evaluating the entire clinical picture and clinically identifiable risks its time to determine where they fall into Low, Moderate or High risk

42. Low risk indeterminate SPN 30 year old male, never smoked, nodule is <1cm with no previous studies, no environmental exposure, found on CT not seen on CXR and no specific pattern found Can follow for two years �OH DOC, I FORGOT TO TELL YOU I HAVE SARCOID!!�

43. Moderate Risk Now you have a patient who isnt clearly low risk. Maybe older age, questionable smoke or environmental history but not quite screaming high risk, what to do? PET SCAN is now recommended

44. PET SCAN Positron emission tomography (PET) with 18-fluorodeoxyglucose (FDG) has proven to be an excellent mode of tumor imaging Increased activity is demonstrated in cells with high metabolic rates, as is seen in tumors and areas of inflammation It can also tell us about if any metastatic disease is present thus altering treatment However the spatial resolution of PET is currently 7 to 8 mm, and so the imaging of SPNs < 1 cm is unreliable $1,912 !!!!

45. Pet Scan Gould et al performed a meta-analysis of the literature on pulmonary nodules and masses and PET scanning and found an overall sensitivity of 96.8% and specificity of 77.8% for detecting malignancy. PET scans also have a 96% sensitivity and 88% specificity with 94% accuracy in the diagnosis of benign nodules

46. Pet Scan So depending on the PET Scan result you can base your treatment If PET is positive than you can refer the patient to CT Surgery for resection options If PET is negative than can follow

47. High Risk Patient 68 year old male, 100 pack years of smoking, used to work with asbestos, and coughing up blood RIGHT TO THE OR for resection.

48. Conclusion The main point is to make sure you give the SPN the respect it deserves. With timely diagnosis we can effectively prevent morbidity and mortality for our patients There is just no excuse for a patient to die because we did not work up the patient in a timely fashion.