Insights into tumour deposit pathology

Correspondence to: Antonio Manenti (e-mail: antonio.manenti_2024@libero.it)

Department of Surgery

Polyclynic Hospital

41124

Modena, Italy

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BJS, https://doi.org/10.1093/bjs/znae309, published 30 December 2024

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The interesting results reported by Lundström et al. about tumour deposits in colon-rectal cancers merit deepened consideration also from a pathophysiological point of view, regarding their possible development1. First, in a tumour the high neoplastic cells proliferative index correlates with its preponderance over other components, such as vessels and interstitial and inflammatory cells. Second, this is often associated with an absent immune and desmoplastic stromal reaction, typically where the tumour cells contact with surrounding adipose cells, whose abundant cytoplasmic fatty components can become nutrients. Similarly, an intra-tumoural presence of irregular zones of fibrous stromal tissue indicates the neoplastic cells overstepping their territorial boundaries, leaving larger spaces available for easier interstitial tissue development. Third, the different condition of ‘stroma reactive invasion front’ indicates a free escape of the neoplastic cells out of their native territories, lack of suitable barriers by the native tissue2. Finally, these neoplastic cells, no longer included in the territory of origin, have to adapt to the new environment. From this moment on, the tumour deposits begin their ‘clandestine’ life, the further steps of which can only be hypothesized. In fact, we don't know whether they will reach blood or lymphatic microvessels and transform into neoplastic emboli, causing distant metastases, or whether they will be eliminated by immunocompetent cells that are subsequently activated, or whether, through a process of progressive aggregation, they will form secondary neoplastic grafts on a serosa, peritoneum or pleura, or by direct contact on a proximal organ, typically the ovary3. In every way, it is clear that the presence of tumour deposits, given also their poor responsivity to adjuvant treatment is a clinically negative prognostic sign4. Given their current possible visibility and diagnosis also by radiomics analysis, their detection is essential in tumour staging5.