Axillary lymphoscintigraphy: current status in the treatment of breast cancer

Scintigraphic investigations of the superficial lymphatic system: quantitative differences between intradermal and subcutaneous injections

RATIONALE AND OBJECTIVES

Both subcutaneous and intradermal injections are used for the scintigraphic investigations of the superficial lymphatic system. The qualitative differences between these types of injections are well known. This study quantified their differences in a group of volunteers.

METHODS

With the limbs at rest, activities in the axillary nodes (AxN) were recorded at 1, 20, 40, 60, 80 and 100 min after subcutaneous or intradermal injection of TC-labelled human serum albumin nanocolloids in the ventral middle part of each forearm of nine young, healthy, male volunteers and the results were compared.

RESULTS

Expressed as per 10,000 of injected activity, activities recorded in the AxN were significantly higher (32.5 times as a mean value, ranging from 8.4 to 130.7 times) after intradermal injections than after subcutaneous injections (P<0.001 by using two-tailed Wilcoxon's signed-rank test). The mean AxN activity after intradermal injections was also apparently higher for the right limbs than for the left limbs, but when the paired t-test was used to compare the right with the left values of the nine volunteers, the comparison did not reach statistical significance (at T+100, 2P=0.087). When their handedness is taken into account, however, a level of statistical significance is reached (at T+100, 2P=0.025).

CONCLUSION

This study quantifies the differences between subcutaneous and intradermal injections, but also shows, although on a limited number of volunteers, that handedness influences the results of the intradermal injections.

Effects of age and lateralization on lymphoscintigraphic interpretation

The present study was undertaken to find out if ageing and lateralization might influence the results of lymphoscintigraphic investigations. Axillary lymphoscintigrams obtained in 756 women after subcutaneous intercostal (IC) injection of 99mTc-labelled colloids at the level of the chest wall were reviewed and analysed according to age (<41 years, 41-50 years, 51-60 years, 61-70 years, 71-80 years, >80 years) and the side injected (right or left). No axillary nodes were visualized (IC-) in 34% of the population, and IC- cases were somewhat, but not significantly (0.10<P<0.05) more frequent after injections in the left side (37%) than after injections in the right side (31%). The frequency of IC - cases increased with age (<41 years, 26%; 41-50 years, 29%; 51-60 years, 36%; 61-70 years, 39%; 71-80 years, 40%; >80 years, four out of seven), and the absence of drainage was more common in patients over 50 years old (overall, 38.2%; right, 36%; left, 40.2%) than in younger cases (overall, 27.9%; right, 24.1%; left, 30.3%). From a statistical point of view, the differences between these two age-discriminated populations were significant both when considering the series of injections as a whole (0.01>2P>0.001) and injections in the right side only (0.01<2P<0.02). In conclusion, ageing and lateralization influence lymphoscintigraphic investigations and have to be taken into account when analysing results.