Multiple myeloma is a cancer of plasma cells, the antibody-producing white blood cells that reside in the bone marrow. Despite remarkable therapeutic advances over the past two decades, including proteasome inhibitors, immunomodulatory drugs and, more recently, antibody-based and cellular therapies, the disease remains incurable, and outcomes vary dramatically between individual patients. Accurate risk stratification at diagnosis is therefore a central goal in myeloma care. The Revised International Staging System, or R-ISS, which combines serum markers such as beta-2 microglobulin and albumin with chromosomal abnormalities detected by interphase fluorescence in situ hybridization and lactate dehydrogenase levels, is the current standard for grouping patients into risk categories. Yet even this framework leaves substantial heterogeneity unexplained, and the authors of the new study argue that systemic inflammation and nutritional impairment, both of which are increasingly recognized as modulators of cancer progression and treatment tolerance, may complement established staging in clinically meaningful ways.

The systemic immune-inflammation index is calculated from a standard complete blood count as the product of the peripheral platelet and neutrophil counts divided by the lymphocyte count. Elevated values reflect a state of heightened systemic inflammation, characterized by increased neutrophil activity and relative lymphopenia, patterns that have been linked to tumor-promoting immune microenvironments in a range of malignancies. The prognostic nutritional index, by contrast, incorporates the absolute lymphocyte count together with serum albumin concentration, integrating immunological competence with visceral protein status. Malnutrition and immune depletion are common in multiple myeloma, driven by the disease itself through factors such as renal impairment, chronic inflammation and cytokine-mediated catabolism, and both are known to compromise the ability of patients to tolerate intensive chemotherapy regimens. The rationale for combining the two indices rests on the idea that inflammation and nutritional decline represent distinct but interacting biological axes, and that patients in whom both are deranged simultaneously should face the greatest risk.

To test this hypothesis, the investigators assembled a retrospective cohort of 164 patients with newly diagnosed multiple myeloma treated at their institution between 2017 and 2024. All patients had pretreatment blood counts and albumin measurements available before the initiation of first-line therapy. Rather than adopting arbitrary cutoffs for the two indices, the team derived thresholds from receiver operating characteristic curves targeting progression-free survival at 36 months, employing both cumulative and dynamic approaches and applying inverse probability of censoring weighting, a statistical technique that corrects for the bias introduced when patients are lost to follow-up. This yielded a cutoff of 382.34 for the SII and 35.40 for the PNI. From these thresholds the researchers constructed a simple 0-to-2-point SII-PNI score, in which points were assigned for elevated inflammation and for impaired nutritional status respectively.

The results were striking. Both progression-free survival and overall survival differed significantly across the score groups, with P values below 0.001 in each case. Patients with higher combined scores, indicating concurrent systemic inflammation and nutritional impairment, experienced markedly shorter times to disease progression and death. The association with progression-free survival was strongest in the early period after diagnosis and attenuated over time, a pattern the authors characterized through time-varying effect analyses, suggesting that the biological state captured by the score is most consequential during the initial phase of disease control when frontline therapy is working to establish remission.

Perhaps the most compelling findings emerged when the researchers dissected the four phenotypes defined by the two indices. Taking patients with low SII and high PNI, the most favorable combination, as the reference group, they calculated adjusted hazard ratios for progression-free survival of 1.997 for patients with high SII alone, 2.052 for those with low PNI alone, and 11.416 for patients with concurrent high SII and low PNI. The corresponding hazard ratios for overall survival were 2.986, 2.998 and 10.292. In other words, while either derangement alone roughly doubled the risk of progression or death, the simultaneous presence of both increased the risk of progression more than elevenfold and the risk of death more than tenfold. This multiplicative pattern supports the central premise of the study: inflammation and nutritional decline are not redundant markers of the same underlying process, but complementary signals whose concordance identifies a uniquely vulnerable patient population.

Importantly, the team did not stop at demonstrating associations. They subjected their score to a battery of validation procedures designed to guard against the optimism that plagues many prognostic models. Bootstrap internal validation confirmed the stability of the model’s performance, and calibration analyses assessed how closely predicted survival probabilities matched observed outcomes. Crucially, the investigators evaluated the incremental value of the SII-PNI score beyond age and the R-ISS, the two most important established predictors available at diagnosis. In a temporal validation cohort consisting of patients treated between 2022 and 2024, a cohort entirely separate from the patients used to derive the model, the Harrell concordance index for progression-free survival was a modest 0.519 when based on age plus R-ISS alone, barely better than a coin flip. When the development-derived SII-PNI score was added, the C-index rose to 0.777, a dramatic improvement in discriminatory capacity that persisted when the analyses were adjusted for treatment modality and other clinical factors.

The implications of these findings extend beyond the statistics. Because the SII and PNI are computed from a complete blood count and a serum albumin measurement, tests performed routinely in virtually every cancer patient worldwide, the combined score costs essentially nothing to obtain and requires no specialized equipment, genetic testing or central laboratory review. In health systems where R-ISS components such as interphase FISH are unavailable or delayed, the SII-PNI score could provide an immediately actionable first-pass risk assessment. Even in well-resourced centers, the score may identify high-risk patients within conventional staging categories, informing decisions about treatment intensification, early consideration of autologous stem cell transplantation, closer surveillance and proactive nutritional support. The authors caution, however, that the score is intended to provide complementary prognostic information rather than to replace established staging frameworks.

As with any single-center retrospective study, limitations warrant consideration. The cohort of 164 patients, while adequate for the analyses performed, is modest in size, and the cutoffs derived from this population will require confirmation in larger, multicenter and ideally prospective cohorts before the score can be recommended for widespread clinical use. Temporal validation within the same institution, though methodologically valuable, does not fully substitute for external validation across populations with different demographics, disease biology and treatment standards. The retrospective design also means that the score’s utility for guiding therapeutic decisions, rather than merely predicting outcomes, remains to be demonstrated in interventional studies. Nevertheless, the magnitude of the observed effects, the rigorous statistical methodology, including inverse probability of censoring weighting and bootstrap validation, and the striking improvement in predictive performance over conventional staging together make a persuasive case that the humble complete blood count, interpreted through the lens of inflammation and nutrition, still has much to teach oncologists about the trajectory of multiple myeloma.

The work was supported by the Fuyang Key Research and Development Program and the Scientific Research Project of the Fuyang Municipal Health Commission, with no funder involvement in study design, data analysis or the decision to publish. The study protocol was approved by the Ethics Committee of Fuyang People’s Hospital, which waived the requirement for informed consent owing to the retrospective nature of the research, and the study was conducted in accordance with the Declaration of Helsinki. The authors declare no competing interests, and the article is published open access under a Creative Commons license. If future studies confirm these results, a two-point score calculated from blood tests ordered on day one of care could become a routine companion to the R-ISS, helping ensure that the patients who need the most aggressive and attentive treatment are identified from the outset of their myeloma journey.

Subject of Research: A retrospective cohort study evaluating a combined systemic immune-inflammation index and prognostic nutritional index score for survival risk stratification in newly diagnosed multiple myeloma.

Article Title: Prognostic value of a combined systemic immune-inflammation index and prognostic nutritional index score for risk stratification in newly diagnosed multiple myeloma: a retrospective cohort study

Article References: Prognostic value of a combined systemic immune-inflammation index and prognostic nutritional index score for risk stratification in newly diagnosed multiple myeloma: a retrospective cohort study. (n.d.). https://doi.org/10.1007/s00277-026-07267-8

Image Credits: AI Generated

DOI: 10.1007/s00277-026-07267-8

Keywords: multiple myeloma, systemic immune-inflammation index, prognostic nutritional index, risk stratification, progression-free survival, overall survival, R-ISS, prognostic markers, retrospective cohort study, hematology, biomarkers, survival prediction