OBSERVATIONS ON THE COMPARATIVE ANATOMY OF BLOOD

forms, such as X and y rays, on the cells of a malignant tissue, there is the equally important indirect or biologicalactionalwaysto be considered. By this, as a result partly of the actualdestruction of the neoplastic tissue (not necessarilyof all of it, however) and partly of the hyperremia and probableextravasationof blood from the very small vessels in the tumour bed, there is induced that wonderful series of biological changeswhich constitute the fibroblastic or healing reaction and which end ideally in perfecthealing of the diseased tissues. This is what Cramercalls the "macrophage reaction", that monocyte-fibroblast-fibrocyte-fibrous tissue sequencewhich is of such great importance in the healing processof any malignant neoplasm. The absenceof superaddedinfection is important also for a good result; it is a radiotherapeutic commonplacenow that an infected or septic lesion takesmuch longer to heal (if it heals at all) than a clean, non-infectedone. Good, adequate irrigation and drainage are, finally, of great importancein radiotherapy. They are bound up to someextent with the state of the tumour bed, for there must be good blood supply and lymphatic drainageif the biological action and effects of irradiation are to operateto the greatest advantage. This hasbeenproved time and againby radiotherapists (and sometimes, but less consciously, by surgeons)in carcinotherapy. Now if, consideringthe commonestor epidermoid type of eesophageal carcinoma,we run throughthese essentialcriteria, we find that half of them, or at least a third, remain unsatisfied. The ordinary squamous-celled carcinomata of the gullet are relatively radio-sensitive (mostly Grade III or GradeIV) and they havea fairly good blood supply and a rich lymphatic drainage (the last-mentioned is really too good from the viewpoint of early nodal extension); so, from these aspects alone, such tumours should respondwell to irradiation. But, on the otherhand,they arein almostevery casewell advancedwhen first seen (either in StageII with definite nodal involvement, or Stage III with distant metastases);seldom if ever do we seean early or StageI caseof oesophageal carcinoma.Also, they must often, becauseof their advancedstage, exhibit evidenceof superaddedinfection, and, lastly andperhapsmostimportantof all, they havea poor, thin and miserable tumour bed to support them. They havenot the good, substantialand comfortable tumour bed of, let us say, a carcinomaof the lip; and so, like the carcinomataof the pharyItx and rectum (all in the wall of a comparatively thin hollow tube), they are not radio-responsive. One need only mention by comparison the radioresponsivenessof the squamous-celledcarcinomata of the lip, of the tongue and of the cervix uteri, similar in type and so in actual radio-sensitivity, but with such different and excellent tumour beds. These, then, are the three necessary conditions which oesophageal growths fail as a rule to satisfy. And when we add to these the three anatomical or structural reasonsalready mentioned, namely, their relative inaccessibility, their early extension through a rich lymphatic drainage system to the regional lymph nodes,and their proximity to vital organs like the lungs, I think we might say that we have a reasonableexplanationof just why carcinomataof the gullet are difficult to treat by irradiation, and why they fail in so many casesto show anything more than a merely palliative responseto the application of radiant energy in whatever form it is administeredto them.