Breast thermography review—and author response

The terms of reference for the thermography review (Fitzgerald and Berentson-Shaw.Thermography as a screening and diagnostic tool: a systematic review. NZMJ 9 March 2012) resulted in a specifically narrow "silo" of acceptable studies relating to breast cancer screening that eliminated most of the thermography literature. However, thermal imaging potentially identifies abnormal breast metabolism prior to oncogenesis. Sequential imaging of hyperthermia and vascular patterns can then show any responses to hormonal, lifestyle or other interventions.Historically, abnormal thermograms have been associated with developing cancer. 1416 patients with persistently abnormal breast thermograms for 8 years had an actuarial breast cancer risk of 26% at 5 years.2 In the 165 patients with non-palpable cancers, thermography was the only test that was positive when compared to mammography and ultrasound in 53% of these patients at initial evaluation. The authors concluded that a persistently abnormal thermogram, even in the absence of any other sign of malignancy, was associated with a high risk of developing interval cancer.2Similarly, 1527 patients with abnormal thermograms were followed for 12 years and 40% developed malignancies within 5 years.3 These so-called "false" positives gained further significance after an abnormal thermogram was associated with more rapidly growing tumours with a shorter disease-free interval.4 Patients with hot tumours have significantly worse disease-free and specific survival than those with cold tumours;5 as do younger women6,7 where 367 of the 2654 breast cancer cases occurred in those ineligible for State-subsidised mammography (NZ National Statistics 2009).Mammography is less specific with fibrocystic breasts with the cancer detection rate falling to 55% in Grade IV breast density.8 Boyd discussing dense fibrocystic breasts concluded "Annual screening in women with extensive mammographic density is not likely to increase cancer detection rate (due to masking).... Attention should therefore be directed to the development and evaluation of alternative imaging techniques for such women".9 In this regard, thermography found 58 of 60 biopsy-proven breast cancers for a 97% sensitivity, 44% specificity, and a 82% negative predictive value in 92 women with dense breasts recommended for breast biopsy based on mammography or ultrasound evaluations.10To quote Kennedy8 "No single tool provides excellent predictability; however, a combination that incorporates thermography may boost both sensitivity and specificity. In light of technological advances and maturation of the thermographic industry, additional research is required to confirm the potential of this technology to provide an effective non-invasive, low risk adjunctive tool for the early detection of breast cancer."The writer imported an American thermography system in 2002 and since 2009 has used the German InfraTec/InfraMedic computerised system registered as a medical device in the EU1and with MedSafe (WAND). The following results demonstrate clinical relevance: A 48-year-old woman with fibrocystic breasts and a normal mammogram and ultrasound (U/S) at age 44 requested a thermogram that revealed a large vascular complex in the upper right breast. Repeated mammography and U/S reported benign fibrocystic breasts. A year later the thermogram had deteriorated with higher contralateral temperatures. Mammography and U/S again reported benign fibrocystic breasts. A surgical opinion was sought and a guided core biopsy performed in some upper outer quadrant thickening. Histology confirmed a Grade 11 lobular carcinoma. A 53-year-old woman requested thermography. Mammography and U/S performed 2 weeks previously had identified fibrocystic changes and indeterminate micro-calcifications deemed inconclusive. The left breast revealed an abnormal vascular complex. Three months later, the thermal image had deteriorated. A repeated mammography and U/S were again reported as only consistent with fibrocystic changes with less obvious micro-calcifications. The thermal abnormality persisted with comparative imaging 6 months and a year later. After further discussion with the radiologist, the patient had magnetic resonance imaging following which an 8mm tumour was identified and confirmed as an infiltrating ductal carcinoma after excision. A 57-year-old woman developed a diffuse, bulky and mobile mass in the upper outer right breast. The mammogram (March 2007) stated: Both breasts show relatively dense stromal appearance with bilateral benign vascular calcification. In the area of clinical concern, there is a focal area of somewhat increased density with reasonably well defined margins. Ultrasound was performed and reported: A 1 ×1.5cm relatively well defined area which is predominantly hypo to anechoic. Internal echoes are seen with good posterior enhancement suggestive of a probable benign cyst. A fine-needle biopsy was reported as benign. The patient requested thermal imaging before making a decision whether to have surgery. Thermography showed heat over the mass and abnormal vascularity. Surgical excision confirmed an infiltrating ductal carcinoma (T2NoMo).Whilst much remains to internationally standardise thermographic technology and protocol, 10 years of breast thermal imaging at the primary health-care level have confirmed clinical usefulness with a unique ability to monitor breast health. It warrants wider support.Michael E Godfrey Retired GP Tauranga, New Zealand