Bronchioloalveolar carcinoma
Synonyms and keywords: Synonym 1; Synonym 2; Synonym 3
| Bronchioloalveolar carcinoma | |
| MeSH | D002282 |
|---|---|
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Manpreet Kaur, MD [2]
Overview
- Bronchioloalveolar carcinoma (BAC) is a rare type of lung cancer which more frequently among never-smokers, women and Asians( particularly Eastern-Asian).[1]
- According to the new WHO classification, Bronchioloalveloar Carcinoma (BAC) is now classified as a subtype of lung adenoacarcinoma and the term BAC is no longer in use[2].
- It is also known as "lepidic predominant adenocarcinoma" due to its progression along the alveolar walls without invading stromal, pleural or vascular tissue[3]
- By definition, BAC is not an invasive tumor. Therefore, pathologists classify it as a form of carcinoma in situ (CIS). However, unlike other forms of CIS, its behavior is malignant, often lethal. Major surgery, either a lobectomy or a pneumonectomy, is needed to control it, and recurrences are frequent. For this reason, oncologists classify it among the other malignant tumors, which are invasive tumors.
Historical prespective
- Bronchioloalveolar carcinoma was first discovered by Dr. Averill Liebow, in the year of 1960.
- In 1999, the World Health Organization has given the term 'Pure BAC' as a subtype of adenocarcinoma that doesn’t Invade.
- In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
- In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].
Classification
According to the current criteria, bronchioloalveolar carcinoma is Pas a sub-type of lung adenocarcinoma and the lesions are now described under categories adenocarcinoma in Situ (AIS) and minimally invasive adenocarcinoma (MIA)[4].
However it is distinct from other lung adenocarcinomas by different clinical features, prognosis and response to treatment.[5]
IASLC/ATS/ERS Classification of Lung Adenocarcinoma in Resection Specimens describes BAC in following subheadings[6];
Adenocarcinoma in situ (AIS) - Previously Known as solitary BAC
- Less than or equal to 3 cm
- Can be either mucinous or serous
- No stromal, lymphatic, or pleural invasion
- No necrosis
- no other growth pattern other than along the airways (lepidic)
Minimally invasive adenocarcinoma (MIA)
- Less than or equal to 3 cm
- Less than or equal to 5 mm area of stromal invasion or other type of growth patterns (in comparison with lepidic pattern of growth)
- Can be mucinous, non mucinous or mixed
Invasive adenocarcinoma
- Presence of stromal invasion or patterns of growth other than lepidic
- Lepidic predominant - Type of invasive adenocarcinoma with more than 5 mm invasion (Previously known as Non Mucinous BAC with invasion)
- Invasive mucinous adenocarcinoma - Previously known as mucinous BAC
The two different sub-types of BAC depending on the cellular cytology are described as follows[7];
Mucinous BAC:
- Less common
- More often seen in non-smokers
- Develop from bronchiolar epithelial metaplasia
- Present oftenly as pneumonia like inflitrate
- Frequently associated with a K-Ras mutation
Non-Mucinous BAC:
- More common
- More often seen in smokers
- Originate from the terminal respiratory cells, type II pneumocytes and clara cells
- Presents usually as a ground glass opacity
- Frequently associated with EFGR mutations
Pathophysiology
Bronchioloalveloar carcinoma or lepidic predominant adenocarcinoma develops in the cells near the alveoli (including type II pnemocytes and clara cells) in the terminal or outer portion of the lungs.
Microscopic Pathology
Causes
Smoking:
- Smoking has not been thought to be associated with BAC generally
- Almost 30 percent patients of BAC are never smokers as compared to adenocarcinoma's (15 percent are never smokers) and squamous cell cancers (only 5 percent are never smokers)[8]
- However some recent pooled studies have shown a two-fold increased risk of BAC in smokers as compared to never-smokers and higher risk with increasing and prolonged consumption with risk decreasing in years following the smoking cessation[9]
- Still, the magnitude of relationship between smoking and adenocarcinoma in situ (BAC) is much smaller than other lung cancers and further studies are needed on this
Genetics:
- Mucinous BAC are frequently associated with K-ras mutations
- Non-mucinous BAC are frequently associated with EFGR mutations
Hypothesis regarding JSRV[10]:
- Jaagsiekte Sheep Retrovirus (JSRV) is a highly infectious retrovirus in sheep that causes low grade tumors in sheep resembling BAC
- This led to the hypothesis that same virus might be responsible for the similar cancer in humans
- However, no molecular study has confirmed this hypothesis so far
Differentiating [disease name] from other Diseases
- [Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
- [Differential dx1]
- [Differential dx2]
- [Differential dx3]
Epidemiology and Demographics
- The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
- In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].
Age
- Patients of all age groups may develop [disease name].
- [Disease name] is more commonly observed among patients aged [age range] years old.
- [Disease name] is more commonly observed among [elderly patients/young patients/children].
Gender
- Women are more commonly affected with BAC than males.
Race
- BAC usually affects individuals of the Asians( particularly Eastern-Asian) ethnicity.
- White individuals are less likely to develop BAC or AIS.
Risk Factors
- Common risk factors in the development of [disease name] are [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].
Natural History, Complications and Prognosis
- The majority of patients with [disease name] remain asymptomatic for [duration/years].
- Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
- If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
- Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
- Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].
Diagnosis
Diagnostic Criteria
- The diagnosis of [disease name] is made when at least [number] of the following [number] diagnostic criteria are met:
- [criterion 1]
- [criterion 2]
- [criterion 3]
- [criterion 4]
Symptoms
- [Disease name] is usually asymptomatic.
- Symptoms of [disease name] may include the following:
- [symptom 1]
- [symptom 2]
- [symptom 3]
- [symptom 4]
- [symptom 5]
- [symptom 6]
Physical Examination
- Patients with [disease name] usually appear [general appearance].
- Physical examination may be remarkable for:
- [finding 1]
- [finding 2]
- [finding 3]
- [finding 4]
- [finding 5]
- [finding 6]
Laboratory Findings
- There are no specific laboratory findings associated with [disease name].
- A [positive/negative] [test name] is diagnostic of [disease name].
- An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
- Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].
Imaging Findings
- There are no [imaging study] findings associated with [disease name].
- [Imaging study 1] is the imaging modality of choice for [disease name].
- On [imaging study 1], [disease name] is characterized by [finding 1], [finding 2], and [finding 3].
- [Imaging study 2] may demonstrate [finding 1], [finding 2], and [finding 3].
Other Diagnostic Studies
- [Disease name] may also be diagnosed using [diagnostic study name].
- Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].
Treatment
Medical Therapy
- There is no treatment for [disease name]; the mainstay of therapy is supportive care.
- The mainstay of therapy for [disease name] is [medical therapy 1] and [medical therapy 2].
- [Medical therapy 1] acts by [mechanism of action 1].
- Response to [medical therapy 1] can be monitored with [test/physical finding/imaging] every [frequency/duration].
Surgery
- Surgery is the mainstay of therapy for [disease name].
- [Surgical procedure] in conjunction with [chemotherapy/radiation] is the most common approach to the treatment of [disease name].
- [Surgical procedure] can only be performed for patients with [disease stage] [disease name].
Prevention
- There are no primary preventive measures available for [disease name].
- Once diagnosed and successfully treated, patients with [disease name] are followed-up every [duration]. Follow-up testing includes [test 1], [test 2], and [test 3]. Effective measures for the primary prevention of [disease name] include [measure1], [measure2], and [measure3].
References
- ↑ Raz, DJ (Mar 2006). "Bronchioloalveolar carcinoma: a review". Clinical Lung Cancer. Cancer Information Group. 7 (5): 313–322. Unknown parameter
|coauthors=ignored (help) - ↑ Butt YM, Allen TC (2015). "The Demise of the Term Bronchioloalveolar Carcinoma". Arch Pathol Lab Med. 139 (8): 981–3. doi:10.5858/arpa.2013-0385-RA. PMID 26230592.
- ↑ Garfield DH, Cadranel J, West HL (2008). "Bronchioloalveolar carcinoma: the case for two diseases". Clin Lung Cancer. 9 (1): 24–9. doi:10.3816/CLC.2008.n.004. PMID 18282354.
- ↑ Travis, William D.; Brambilla, Elisabeth; Nicholson, Andrew G.; Yatabe, Yasushi; Austin, John H.M.; Beasley, Mary Beth; Chirieac, Lucian. R.; Dacic, Sanja; Duhig, Edwina; Flieder, Douglas B.; Geisinger, Kim; Hirsch, Fred R.; Ishikawa, Yuichi; Kerr, Keith M.; Noguchi, Masayuki; Pelosi, Giuseppe; Powell, Charles A.; Tsao, Ming Sound; Wistuba, Ignacio (2015). "The 2015 World Health Organization Classification of Lung Tumors". Journal of Thoracic Oncology. 10 (9): 1243–1260. doi:10.1097/JTO.0000000000000630. ISSN 1556-0864.
- ↑ Lee, KS (Nov–Dec 1997). "Bronchioloalveolar carcinoma: clinical, histopathologic, and radiologic findings" (PDF). RadioGraphics. 17 (6): 1345–1357. PMID 9397450. Retrieved 2007-12-03. Unknown parameter
|coauthors=ignored (help) - ↑ New Pathologic Classification of Lung Cancer: Relevance for Clinical Practice and Clinical Trials William D. Travis, Elisabeth Brambilla, and Gregory J. Riely Journal of Clinical Oncology 2013 31:8, 992-1001
- ↑ Garfield DH, Cadranel J, West HL (2008). "Bronchioloalveolar carcinoma: the case for two diseases". Clin Lung Cancer. 9 (1): 24–9. doi:10.3816/CLC.2008.n.004. PMID 18282354.
- ↑ Bracci PM, Sison J, Hansen H, Walsh KM, Quesenberry CP, Raz DJ; et al. (2012). "Cigarette smoking associated with lung adenocarcinoma in situ in a large case-control study (SFBALCS)". J Thorac Oncol. 7 (9): 1352–60. doi:10.1097/JTO.0b013e31825aba47. PMC 3421052. PMID 22814813.
- ↑ Boffetta P, Jayaprakash V, Yang P, Asomaning K, Muscat JE, Schwartz AG; et al. (2011). "Tobacco smoking as a risk factor of bronchioloalveolar carcinoma of the lung: pooled analysis of seven case-control studies in the International Lung Cancer Consortium (ILCCO)". Cancer Causes Control. 22 (1): 73–9. doi:10.1007/s10552-010-9676-5. PMC 3002160. PMID 21072579.
- ↑ Mornex JF, Thivolet F, De las Heras M, Leroux C (2003). "Pathology of human bronchioloalveolar carcinoma and its relationship to the ovine disease". Curr Top Microbiol Immunol. 275: 225–48. PMID 12596901.
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