Application of nuclear medicine methods in patients with breast cancer

Sammanfattning: While physical examination, mammography and aspiration cytology or core biopsy form the basis in the diagnosis of breast cancer, additional examinations are sometimes required in the evaluation of unclear breast masses. The study deals with the application and evaluation of different nuclear medicine techniques in the diagnosis and treatment of breast cancer. Study I evaluates the addition of mammoscintigraphy with 99mTc-MIBI to the standard diagnostic techniques. Adding mammoscintigraphy in 96 women with unclear breast lesions increased the sensitivity of palpable cancers from 96% to 100%, and from 89% to 97% for nonpalpable cancers. This, on the other hand, reduced the specificity. Study II It has been reported that 99mTC-MDP, an agent for bone scintigraphy, may be used also to depict breast cancers. Combining this would represent a rationalization. Since no robust comparisons are reported, the uptake of 99mTC-MDP and 99mTC-MIBI was compared in 20 women with large breast cancers. 99mTc-MDP depicts the tumour with the same uptake versus the background as 99mTc-MIBI in post-menopausal women not on hormonal replacement therapy. Otherwise, 99mTc-MIBI gives a higher contrast. Study III evaluates the possibility to assess the effect of neoadjuvant chemotherapy (5-FU, epirubicin and cyclophosphamide) of large breast cancer with mammoscintigraphy using 99mTcMIBI and SPECT. After finished chemotherapy there was a strong reduction of the tumour uptake, while after one therapy course no effect was detected. Study IV In order to localise the sentinel node(s) at surgery of breast cancer, a gammacamera examination is often made after injection of the radiocolloid. To improve the anatomical orientation by visualizing the soft tissue background at this examination, 25 MBq of pertechnetate was administered iv. also in 41 consecutive patients. As this activity may obscure the lymph node uptake, the number of visualised nodes was compared with that of 47 patients not given pertechnetate. There was no difference in the number of detected nodes between the patient groups. Hence, administration of pertechnetate does not reduce this detectability, while the orientation is improved. Study V 99mTC-HMPAO is an agent for examination the regional brain blood flow. The uptake of 99mTc-HMPAO was compared with that of 99mTc-MIBI in 21 consecutive women with breast cancer (>= 1 cm). In the entire patient group, the sensitivity of the agents was the same, while in the individual patients there was a restricted agreement. This may be used to evaluate tumour characteristics in vivo since the uptake mechanism of both agents are involved in resistance to anti-neoplastic drugs. Nuclear medicine examinations are complementary to other methods for the diagnosis and the evaluation of breast cancer. New nuclear medicine techniques have to be evaluated and used if found valuable, or rejected if they do not add any information.