{"id":1301,"date":"2017-05-10T10:38:11","date_gmt":"2017-05-10T10:38:11","guid":{"rendered":"http:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/?p=1301"},"modified":"2017-08-22T10:16:19","modified_gmt":"2017-08-22T10:16:19","slug":"primary-care-corner-with-geoffrey-modest-md-management-of-incidental-pulmonary-nodules","status":"publish","type":"post","link":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/2017\/05\/10\/primary-care-corner-with-geoffrey-modest-md-management-of-incidental-pulmonary-nodules\/","title":{"rendered":"Primary Care Corner with Geoffrey Modest MD: Management of incidental pulmonary nodules"},"content":{"rendered":"

by Dr Geoffrey Modest<\/strong><\/p>\n

\u200bThe\u00a0Fleischner\u00a0Society guidelines for the management of incidental pulmonary nodules found on CT scans was just updated, involving\u00a0international input\u00a0from radiologists, pulmonologists, surgeons, pathologists\u00a0(see\u00a0doi:10.1148\/radiol.2017161659\u200b).<\/p>\n

 <\/p>\n

Details:<\/strong><\/p>\n

–the guidelines refer to incidental pulmonary\u00a0nodules found by CT scan in those >35yo, not for patients at high risk (eg\u00a0in those with cancer who might have\u00a0mets,\u00a0or those getting CTs\u00a0for screening purposes)<\/p>\n

–the minimum threshold size leading to\u00a0 recommendation for\u00a0nodule\u00a0follow-up is if the estimated cancer risk is >1% (arbitrarily chosen)<\/p>\n

–follow-up CTs should use low-radiation techniques, no more than 3\u00a0mGy\u00a0in a standard sized person, in order to reduce radiation exposure,\u00a0esp\u00a0in patients likely to receive many of them.<\/p>\n

 <\/p>\n

—Single solid nodules<\/strong><\/p>\n

— <6 mm (a\u00a0larger size\u00a0than prior guidelines):\u00a0no further follow-up studies (grade 1C, strong recommendation, low- or very-low quality of evidence). Those at higher risk (see below), such as\u00a0suspicious morphology or\u00a0upper lobe location\u00a0has optional\u00a0recommendation to\u00a0repeat CT but\u00a0not before\u00a012 months (small risk by waiting this long\u00a0and earlier study might provide false reassurance)<\/p>\n

— 6-8mm and low clinical risk (see below): follow-up 6-12 months, depending on size, morphology and patient preference (grade 1C, strong recommendation, low- or very-low quality of evidence\u200b). usually one follow-up exam is sufficient, though optional one at 18-24 months. For those at higher risk, this additional 18-24 month follow-up is recommended.\u00a0\u00a0(strong recommendation,\u00a0moderate\u00a0quality of evidence\u200b)\u200b. average risk of cancer 0.5-2%<\/p>\n

— >8mm: same recommendation independent of risk: CT at 3 months, PET\/CT, or tissue sampling\u00a0(grade 1A, strong recommendation, high quality of evidence). average risk of cancer 3%<\/p>\n

—Multiple solid nodules<\/strong><\/p>\n

–dominant nodule <6mm: same as with single\u00a0(Grade 2B, weak recommendation,\u00a0moderate\u00a0quality of evidence\u200b)\u200b.<\/p>\n

–6-8 mm: same as with single, but initial follow-up CT at 3-6 months (optional follow-up at 18-24 months if low risk, recommended if high risk).\u00a0Grade 1B, strong recommendation,\u00a0moderate\u00a0quality of evidence\u200b\u200b.<\/p>\n

–>8 mm: same as 6-8mm<\/p>\n

—Single\u00a0subsolid\u00a0nodules<\/strong><\/p>\n

–ground glass nodule: <6mm,\u00a0no routine follow-up; >6mm, CT at 6-12 months to confirm persistence, then every 2 years for 5 years\u200b.\u00a0(grade 1B; strong recommendation, moderate-quality evidence). Approximately 10% grow and\u00a01% progress to adenocarcinoma, in a study done in\u00a0Asian population.<\/p>\n

–part solid nodule: <6mm, no routine follow-up; >6mm, CT at 3-6 months to confirm persistence (could be infectious and resolve). If solid component remains <6mm, annual CT for 5 years\u00a0\u00a0(grade 1C; strong recommendation, low- or very-low-quality evidence). If solid component\u00a0>6mm, highly suspicious for cancer\u00a0(grade 1B; strong recommendation, moderate quality evidence.)<\/p>\n

—Multiple\u00a0subsolid\u00a0nodules<\/strong><\/p>\n

–<6mm: CT at 3-6 months. If stable, consider repeat at 2 and 4 years (grade 1C; strong recommendation, low- or very-low-quality evidence)<\/p>\n

–>6mm: CT at 3-6 months. if persistent, consider diagnosis of\u00a0multiple primary adenocarcinomas (grade 1C; strong recommendation, low- or very-low-quality evidence).\u00a0subsequent management depends on most suspicious nodule.<\/p>\n

 <\/p>\n

—risk factors for malignancy<\/strong>:<\/p>\n

–nodule size is the dominant risk factor<\/p>\n

–nodules are classified as\u00a0solid, pure ground glass, and part-solid. BUT huge inter- and intra-observer disagreements (correct classification of nodules as solid or sub-solid was found in only 58% of cases!!<\/strong>). Those with marginal spiculation are more likely to be malignant (OR 2.2-2.5), though this is not really a binary finding, and no threshold of the degree of spiculation\u00a0has been defined<\/p>\n

–nodule location: upper lobes, and\u00a0esp\u00a0right upper lobe, more likely to be cancer, with odds ratio of about 2.0 \u00a0Adenocarcinomas and\u00a0mets\u00a0are more likely peripheral, and squamous cell cancers are more near the\u00a0hila. Small nodules in\u00a0perifussural\u00a0or subpleural areas often are lymph\u00a0nodes<\/p>\n

–nodule multiplicity: increased risk of cancer as number of nodules increases from 1 to 4, but decreases with >4 (more likely\u00a0prior granulomatous infection)<\/p>\n

–nodule growth rate: solid cancers double their volume (a 26% increase in diameter) in 100-400 days;\u00a0subsolid\u00a0nodules (eg,\u00a0primary adenocarcinomas) have average doubling times of 3-5 years: hence the longer follow-up time for those with\u00a0subsolid\u00a0nodules<\/p>\n

–emphysema\/fibrosis: emphysema is independent risk factor for cancer. Old studies found about 3x increase. NLST \u00a0(National\u00a0Lung\u00a0Screening Trial, which led to current screening recommendations for smokers)\u00a0found incidence of 25 cancers\/1000 screened in those with emphysema and 7.5\/1000 in those without. Both emphysema-predominant COPD and\u00a0increasing severity of centrilobular emphysema increase the risk of cancer. As does pulmonary fibrosis (esp\u00a0idiopathic pulmonary fibrosis, with\u00a0HR 4.2)<\/p>\n

\u200b–age\/demographics:\u00a0rare <40yo, and increases each decade of life. Women may be at higher risk in a few studies:\u00a0esp\u00a0if lower BMI and lower educational level, but also a higher cancer risk in\u00a0women with nonsolid nodules. Family history\u00a0\u00a0is a risk factor both in smokers and never-smokers, with\u00a0RR 1.5-1.8 if an affected sibling. Also higher in black men\u00a0and native Hawaiian men at lower levels of smoking.<\/p>\n

–tobacco\/exposures. 10- to 35-fold increased risk in smokers. passive smokers also\u00a0with increased risk, but less so.\u00a0smoking mostly associated with\u00a0squamous cell cancers. incidence of adenocarcinomas is increasing over time,\u00a0esp\u00a0for female nonsmokers, but unclear effect of smoking on this and smoking\u00a0not included as a\u00a0risk factor for\u00a0adenocarcinomas. other inhaled carcinogens noted\u00a0as cancer risk factors include asbestos, uranium and radon. [silicosis may be, but\u00a0not shown conclusively, per my reading. similar with beryllium exposure. and, no doubt, others]<\/p>\n

–the categories of risk used in this guideline are\u00a0from the American College of Chest Physicians\u00a0(these are spelled out, with a mathematical equation<\/a> including the variety of risk factors:<\/p>\n

–low-risk: estimated cancer risk (<5%), found typically in those of young age, less smoking, smaller nodule size, regular margins, and location other than upper lobe<\/p>\n

–high\u00a0risk (>5%), more often if older age, heavy smoking, larger nodule size, irregular or spiculated margins, and upper lobe location<\/p>\n

–one not-so-uncommon clinical situation is the patient who has an abdominal CT, where the CT finds\u00a0a small lung\u00a0nodule (<6mm), but only the lower part of the lungs is visualized. If\u00a0patient is low risk, no further follow-up recommended. If intermediate size (6-8mm), follow-up CT of the complete chest after 3-12 months depending on clinical risk. \u00a0If larger nodule or suspicious characteristics, full chest CT right away\u00a0for further evaluation<\/p>\n

 <\/p>\n

Commentary:<\/strong><\/p>\n

–with increasing use of CT scans, lots of lung nodules are found. in US\u00a0adults between 2006-14, more than 4.8 million had at least one chest CT, with >1.5 million nodules identified, and 63K lung cancers diagnosed within 2 years.<\/p>\n

–I\u00a0would personally include as higher risk any\u00a0patients with\u00a0industrial exposures\u00a0esp\u00a0if there is evidence of distorted lung parenchyma (eg\u00a0fibrosis, as by silicosis), especially since other causes of fibrosis are higher risk (emphysema, idiopathic\u00a0pulmonary\u00a0fibrosis). and I\u00a0would be more inclined to follow them more closely, as well as caution them about avoiding\u00a0any other exposures more aggressively (smoking, etc).<\/p>\n

–they do not mention HIV in this guideline (they refer to immunocompromise as creating higher likelihood of infection, no mention of cancer), but there are observational studies of 2- to 4-fold\u00a0increased risk of lung cancer\u00a0at younger age and lower smoking exposure: I\u00a0had a patient who was an elite controller, who\u00a0had an\u00a0undetectable viral load, high CD4 count off any antiretroviral\u00a0meds, minimal smoking history, but\u00a0who died in his late 40s from lung cancer. My\u00a0review of the literature found this phenomenon not so uncommon, even in patients with good immunologic response to antiretrovirals.\u00a0\u00a0so I\u00a0would add HIV, controlled or not, as potential risk factor<\/p>\n

–I\u00a0am very concerned about radiation exposure (as per many prior blogs<\/a>). Above they mention that the repeat CT scans done should produce only\u00a03 mGy of radiation exposure.\u00a0LDCT, low-dose CT used for screening smokers, is 1.5\u00a0mSv, which from my search is the same as 1.5\u00a0mGy, whereas a diagnostic chest CT is about 7-8\u00a0mGy, and\u00a0a chest xray about 0.1\u00a0mGy. So the recommended radiation dose for the\u00a0follow-up repeat\u00a0CT\u00a0is less than 1\/2 that of a\u00a0regular diagnostic CT. I’m\u00a0not sure exactly\u00a0what that means. Is the follow-up CT different from a diagnostic CT?? Or are they recommending new\u00a0CT scanners which deliver less radiation, but may not be available in many places (and might limit the generalizability or utility of their algorithm, since more cancers may be created by the\u00a0higher radiation exposure)? There was an article about a new Toshiba CT scanner which delivers around 4\u00a0mGY:\u00a0see\u00a0https:\/\/www.technologyreview.com\/s\/510861\/ct-scanner-delivers-less-radiation\/<\/a>\u200b , which may be what they are referring to….<\/p>\n

–BUT,\u00a0one concern I have\u00a0is that the additional radiation exposure from multiple CTs (even from\u00a0lower radiation ones)\u00a0might have an\u00a0even higher\u00a0risk of causing cancer in patients with baseline abnormal lungs. The data on radiation exposure and cancer, from what I can find, is largely mathematical\u00a0modeling based on people with normal lungs (eg\u00a0Einstein AJ JAMA 2007; 298: 317, as well as here <\/a>, here<\/a>\u00a0,\u00a0and here<\/a>). My guess, though not addressed in anything I\u00a0have seen, is that those with diseased lungs are at higher risk of radiation-related lung cancer, and\u00a0that\u00a0risk may be much higher than estimates from the current mathematical models of people with normal lungs (eg, maybe the underlying lung pathology is associated with inflammation and fibrosis which is associated with\u00a0significant chromosomal damage, etc, which puts the lungs at higher cancer risk from further damage by radiation??? sort of a multiple-hit theory??)<\/p>\n

 <\/p>\n

So, I think this guideline is helpful for us in primary care. Given the rather low bar to get CT scans these days\u00a0and the frequent finding of difficult-to-interpret incidental \u201cabnormalities\u201d found, it is useful to have some sense of how to interpret and follow the findings, and why. of course, there are real concerns about the radiation exposure, but at least these guidelines are more lenient than prior ones (larger size cutpoint of when to do followup CTs, and less aggressive followup than before)\u200b<\/p>\n

\u00a0<\/strong><\/p>\n

 <\/p>\n

<\/div>\n","protected":false},"excerpt":{"rendered":"

Management of incidental pulmonary nodules […]<\/p>\n

Read More…<\/a><\/p>\n","protected":false},"author":318,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[14283],"tags":[],"class_list":["post-1301","post","type-post","status-publish","format-standard","hentry","category-archive"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/posts\/1301","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/users\/318"}],"replies":[{"embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/comments?post=1301"}],"version-history":[{"count":0,"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/posts\/1301\/revisions"}],"wp:attachment":[{"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/media?parent=1301"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/categories?post=1301"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/wp-json\/wp\/v2\/tags?post=1301"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}